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Background: CaO-SiO2-P2O5-B2O3 bioactive glass-ceramics7 (BGS-7) are known for their strong integration with bone and stability and are commonly used in spinal fusions. Purpose: This study aimed to compare fusion rates and radiological and clinical outcomes between BGS-7 and allograft spacers with iliac bone grafts (IBG) in multilevel anterior cervical discectomy and fusion (ACDF) surgeries. Study design/setting: This retrospective study was conducted at BRM Medical Center. Patient sample: We included patients who underwent multilevel ACDF at BRM Medical Center between January 2012 and December 2023. The patients had symptoms such as cervical radiculopathy and myelopathy due to cervical disc herniation, stenosis, and spondylosis. Outcome measures: We evaluated the preoperative and postoperative Japanese Orthopedic Association (JOA) scores, neck disability index (NDI), functional rating index (FRI), and visual analog scale (VAS) scores for the neck, shoulder, and upper extremities at 6 months and 1 year after surgery. Methods: Fusion rates were assessed using dynamic radiography and computed tomography (CT) scans at 1 year postoperatively. Radiological measurements were obtained from preoperative and postoperative plain radiographs. Results: At the 1-year follow-up, the fusion rates were 89.5% for BGS-7 and 92.2% for the allograft cage on dynamic radiographs (p=0.156) and 93.4% and 90.4%, respectively, on CT scans (p=0.319), confirming both internal and external osseointegration. Subsidence rates were 4% for BGS-7 and 10% for the allograft spacer group. Both groups showed increased cervical lordosis (CL), segmental lordosis (SL), and segmental height postoperatively, with maintained lower segmental height (LSH) in the BGS-7 group than in the allograft spacer group at postoperatively 1 year. No adjacent segmental disease (ASD) occurred in either group. The JOA, NDI, and FRI showed significant improvements in both groups. The VAS scores decreased significantly in both groups, indicating improved clinical outcomes. Conclusions: In multilevel ACDF, BGS-7 demonstrated fusion rates comparable to those of the allograft spacer with IBG, experiencing fewer instances of subsidence and cage fracture. Therefore, BGS-7 spacer can be safely utilized in multilevel ACDF as a substitute for traditional allograft spacers, without the need for additional IBG. [ABSTRACT FROM AUTHOR]

Background: Degenerative lumbar spondylolisthesis (DLS) with lumbar spinal stenosis (LSS) is a common condition resulting in substantial lower back pain and disability. Surgical intervention is recommended only when conservative treatment fails. This study compared UBE-TLIF and MIS-TLIF regarding clinical outcomes and fusion rates in patients with single-segment DLS with LSS. Methods: A total of 85 patients who underwent either UBE-TLIF (n = 40) or MIS-TLIF (n = 45) were examined retrospectively. Clinical results were evaluated by the Visual Analog Scale (VAS) for pain and the Oswestry Disability Index (ODI) for functional outcomes. Radiographs and CT were utilized to assess radiological outcomes such as disc height (DH), lumbar lordosis (LL), and interbody fusion rates. The two groups were also compared in terms of perioperative data (operation time, blood loss, hospital stay, and fluoroscopy exposure). Results: Both surgical techniques showed similar statistically significant improvements in VAS and ODI scores. Fusion rates at 2 years postoperatively were identical, including 95% for the UBE-TLIF group and 97.7% for the MIS-TLIF group. However, compared with MIS-TLIF, the operative time and fluoroscopy exposure were longer for UBE-TLIF, but intraoperative blood loss and length of hospital stay were reduced. Conclusions: UBE-TLIF and MIS-TLIF can successfully treat single-segment DLS in the presence of LSS, achieving similar clinical and radiological outcomes with low complication rates. Although UBE-TLIF has certain advantages regarding perioperative outcomes (less blood loss and shorter hospital stay), MIS-TLIF is associated with shorter operative times and lower fluoroscopy exposure. [ABSTRACT FROM AUTHOR]

Objective: Anterior cervical discectomy and fusion (ACDF) with anterior plating is a commonly performed procedure for cervical disc diseases. While the clinical outcomes of most reported multilevel ACDF cases are excellent, symptomatic pseudarthrosis remains a challenge, often requiring revision surgeries. This study aims to present the radiological characteristics of multilevel ACDF constructs, which can be considered during intraoperative management to prevent pseudarthrosis. Methods: This retrospective cohort study included patients who underwent multilevel (3 or 4 levels) ACDF with anterior plating between June 2010 and August 2022. Patients were regularly followed at 4 months, 12 months, and then annually postoperation. Fusion rates and characteristic radiological patterns, such as the formation of bony buttresses underneath the anterior plate, were graded and evaluated. Results: A total of 163 patients were included in the study. Overall fusion rates were 26.38%, 64.34%, and 81.58% at 4-month, 1-year, and the final follow-up, respectively. Nonunions at 4-month follow-up with tightly engaged anterior plate with bony buttress formation were more likely to fuse in the later period (Buttress grade 0 vs. 1; p=0.01, odds ratio [OR], 5.70, Buttress grade 1 vs. >2; p<0.01, OR, 12.00). Conclusion: This study emphasizes the significance of pseudarthrosis following multilevel ACDF. Pseudarthrosis predominantly occurs in the caudal-most segment of the construct, particularly when it terminates at C7. Constructs that are not tightly engaged and lack bony buttress formation in the caudal part of multilevel ACDF are more likely to develop pseudarthrosis. [ABSTRACT FROM AUTHOR]

Objective Biportal endoscopic transforaminal lumbar interbody fusion (BE-TLIF) is an emerging, minimally invasive technique performed under biportal endoscopic guidance. However, concerns regarding cage subsidence and sufficient fusion during BE-TLIF necessitate careful selection of an appropriate interbody cage to improve surgical outcomes. This study compared the fusion rate, subsidence, and other radiographic parameters according to the material and size of the cages used in BE-TLIF. Methods In this retrospective cohort study, patients who underwent single-segment BE-TLIF between April 2019 and February 2023 were divided into 3 groups: group A, regular-sized three-dimensionally (3D)-printed titanium cages; group B, regular-sized polyetheretherketone cages; and group C, large-sized 3D-printed titanium cages. Radiographic parameters, including lumbar lordosis, segmental lordosis, anterior and posterior disc heights, disc angle, and foraminal height, were measured before and after surgery. The fusion rate and severity of cage subsidence were compared between the groups. Results No significant differences were noted in the demographic data or radiographic parameters between the groups. The fusion rate on 1-year postoperative computed tomography was comparable between the groups. The cage subsidence rate was significantly lower in group C than in group A (41.9% vs. 16.7%, p=0.044). The severity of cage subsidence was significantly lower in group C (0.93±0.83) than in groups A (2.20±1.84, p=0.004) and B (1.79±1.47, p=0.048). Conclusion Cage materials did not affect the 1-year postoperative outcomes of BE-TLIF; however, subsidence was markedly reduced in large cages. Larger cages may provide more stable postoperative segments.

Taking E690 marine steel as the research object, a new technology of laser forging coupled arc welding is developed. The influence of arc current and arc voltage on arc welding porosity morphology and the influence of arc current and arc voltage on arc welding fusion ratio are studied. The effect of different filament spacing, laser defocusing amount and groove width on pore morphology was studied. The arc shape and droplet characteristics of laser forging coupled arc welding are analysed. Optimal processing parameters were an arc current of 165 A, arc voltage of 28 V and welding speed of 550 mm/min. With these the weld bead shape of arc welding is good, the splash is less and the weld bead is sound. Also, the fusion ratio is the highest at 38.891% and the fusion area is also high at 19.028 mm2. at the same time, stress concentration and porosity defects are caused. When laser impact forging is added, the fusion ratio of the weld seam at the position of 6 to 8 mm is the highest, which is 39.247 and 39.168%, respectively. The fusion area is the largest, with the fusion area of 20.340 and 19.373 mm2, respectively. With the increase of arc current and arc voltage the arc profile gradually increases, the arc stability decreases, the heat is dissipated and the temperature difference is large. With laser forging coupled arc welding, the heat is relatively concentrated, and the arc profile decreases with the increase of distance between laser and arc. The laser impact forging can gather the arc energy, attract the arc and improve the forming quality of the weld. [ABSTRACT FROM AUTHOR]

Background: Biportal endoscopic transforaminal lumbar interbody fusion (BE-TLIF) is a minimally invasive surgical technique for treating degenerative lumbar spine conditions. It offers advantages such as reduced soft tissue trauma and lower infection rates, but certain technical aspects may be challenging. The current study aims to identify strategies to enhance the fusion rate in BE-TLIF by addressing these specific challenges. Methods: A literature review was conducted on techniques to improve fusion rates in BE-TLIF. Results: The review suggests that lateral-based portals supplemented with medial portals allowed for safe insertion of interbody cages with large footprint. Direct visualization of the disc space with a 30° endoscope assisted with better disc space preparation. Facetectomies performed with osteotomes, rather than burrs, ensured maximum retrieval of autologous bone graft. Utilizing bone morphogenetic proteins with sustained release carriers such as hydroxyapatite can be useful to increase fusion rates of BE-TLIF. Conclusions: To our knowledge, the current literature is the first comprehensive review of strategies to enhance fusion rates in BE-TLIF. The proposed techniques and biological adjuncts are effective means to address key challenges associated with the procedure, and such strategies would potentially shorten the learning curve and improve clinical outcomes. Further clinical studies are required to validate these findings and establish standardized protocols. Clinical Relevance: These findings provide practical solutions to overcome common challenges in BE-TLIF. The suggested techniques would reduce the incidence of pseudarthrosis, improve patient outcomes, and ultimately offer a safer and more reliable option for lumbar interbody fusion patients. Level of Evidence: 5. [ABSTRACT FROM AUTHOR]

Electrical stimulation is an important adjuvant therapy for spinal surgery, but whether receiving electrical stimulation can improve the fusion rate after spinal surgery is still controversial. The purpose of this study was to analyse and evaluate the effect of electrical stimulation on the fusion rate after spinal surgery. We systematically searched for related articles published in the PubMed, Embase and Cochrane Library databases on or before September 30, 2023. The odds ratio (OR) with 95% confidence interval (CI) and the fusion rates of the experimental group and the control group were calculated by a random-effects meta-analysis model. The analysis showed that receiving electrical stimulation significantly increased the probability of successful spinal fusion (OR 2.66 [95% CI 1.79–3.97]), and the average fusion rate of the electrical stimulation group (86.8%) was significantly greater than that of the control group (73.7%). The fusion rate in the direct current (DC) stimulation group was 2.33 times greater than that in the control group (OR 2.33 [95% CI 1.37–3.96]), and that in the pulsed electromagnetic field (PEMF) group was 2.60 times greater than that in the control group (OR 2.60 [95% CI 1.29–5.27]). Similarly, the fusion rate in the capacitive coupling (CC) electrical stimulation group was 3.44 times greater than that in the control group (OR 3.44 [95% CI 1.75–6.75]), indicating that regardless of the type of electrical stimulation, the fusion rate after spinal surgery improved to a certain extent. Electrical stimulation as an adjuvant therapy seems to improve the fusion rate after spinal surgery to a certain extent, but the specific effectiveness of this therapy needs to be further studied. [ABSTRACT FROM AUTHOR]

Objective: Biportal endoscopic transforaminal lumbar interbody fusion (BE-TLIF) is an emerging, minimally invasive technique performed under biportal endoscopic guidance. However, concerns regarding cage subsidence and sufficient fusion during BE-TLIF necessitate careful selection of an appropriate interbody cage to improve surgical outcomes. This study compared the fusion rate, subsidence, and other radiographic parameters according to the material and size of the cages used in BE-TLIF. Methods: In this retrospective cohort study, patients who underwent single-segment BE-TLIF between April 2019 and February 2023 were divided into 3 groups: group A, regular-sized three-dimensionally (3D)-printed titanium cages; group B, regular-sized polyetheretherketone cages; and group C, large-sized 3D-printed titanium cages. Radiographic parameters, including lumbar lordosis, segmental lordosis, anterior and posterior disc heights, disc angle, and foraminal height, were measured before and after surgery. The fusion rate and severity of cage subsidence were compared between the groups. Results: No significant differences were noted in the demographic data or radiographic parameters between the groups. The fusion rate on 1-year postoperative computed tomography was comparable between the groups. The cage subsidence rate was significantly lower in group C than in group A (41.9% vs. 16.7%, p=0.044). The severity of cage subsidence was significantly lower in group C (0.93±0.83) than in groups A (2.20±1.84, p=0.004) and B (1.79±1.47, p=0.048). Conclusion: Cage materials did not affect the 1-year postoperative outcomes of BE-TLIF; however, subsidence was markedly reduced in large cages. Larger cages may provide more stable postoperative segments. [ABSTRACT FROM AUTHOR]

The exact evaluation of the fusion rate of virgin and aged asphalt is essential to optimize the performance of the recycled asphalt mixture. The fusion rate index was developed by tracing the distribution of tracer asphalt, which contains nano-ferrous ferric oxide (nano-Fe3O4) tracer. Laboratory fusion simulation tests were performed on three types of asphalt to obtain different fusion states, and fatigue tests were performed to evaluate the influence of the fusion rate on the fatigue life of the recycled asphalt. It was found that the tracer asphalt containing 4% nano-Fe3O4 shows the optimal trace effect, and the developed fusion rate index can quantitatively characterize the influence of different factors on the fusion state of the recycled asphalt. The fusion state is closely related to the fatigue performance of recycled asphalt, and the fusion rate index can fairly evaluate its fatigue performance. The relationship between the fusion rate and the fatigue life of recycled asphalt depends on the factors that cause the fusion rate variation. Under the influence of the amount of rejuvenator, the fatigue life of recycled asphalt grows exponentially with increasing fusion rate due to enhancement of molecular motion as well as a supplement of lightweight components. Under the influence of heat preservation treatment, fatigue life increases linearly with increasing fusion rate. The proposed fusion rate index can be utilized to quantitatively characterize the fusion state of virgin and aged asphalt, thus providing a simple way to guide the practical application of recycled asphalt.

Abstract Objective Autologous iliac bone is commonly used as a bone graft material to achieve solid fusion in craniocervical junction (CVJ) surgery. However, the developing iliac bone of children is less than ideal as a bone graft material. The matured rib bone of children presents a potential substitute material for iliac bone. The aim of this study was to evaluate the efficacy of autologous rib grafts for craniocervical junction surgery in children. Methods The outcomes of 10 children with abnormalities of the craniocervical junction who underwent craniocervical junction surgery between January 2020 and December 2022 were retrospectively reviewed. All patients underwent posterior fusion and internal fixation surgery with autologous rib grafts. Pre- and post-operative images were obtained and clinical follow-ups were conducted to evaluate neurological function, pain level, donor site complications, and bone fusion rates. Results All surgeries were successful. During the 8- to 24-month follow-up period, all patients achieved satisfactory clinical results. Computed tomography at 3–6 months confirmed successful bone fusion and regeneration of the rib defect in all patients with no neurological or donor site complications. Conclusion Autologous rib bone is a safe and effective material for bone grafting in craniocervical junction fusion surgery for children that can reduce the risks of donor site complications and increase the amount of bone graft, thereby achieving a higher bone fusion rate.

Study designRetrospective cohort study.ObjectiveTo compare the outcomes of patients with adult spinal deformity (ASD) following spinal fusion with the lowest instrumented vertebra (LIV) at L4/L5 versus S1/ilium.MethodsA multicenter ASD database was evaluated. Patients were categorized into 2 groups based on LIV levels-groups L (fusion to L4/L5) and S (fusion to S1/ilium). Both groups were propensity matched by age and preoperative radiographic alignments. Patient demographics, operative details, radiographic parameters, revision rates, and health-related quality of life (HRQOL) scores were compared.ResultsOverall, 349 patients had complete data, with a mean follow-up of 46 months. Patients in group S (n = 311) were older and had larger sagittal and coronal plane deformities than those in group L (n = 38). After matching, 28 patients were allocated to each group with similar demographic, radiographic, and clinical parameters. Sagittal alignment restoration at postoperative week 6 was significantly better in group S than in group L, but it was similar in both groups at the 2-year follow-up. Fusion to S1/ilium involved a longer operating time, higher PJK rates, and greater PJK angles than that to L4/L5. There were no significant differences in the complication and revision rates between the groups. Both groups showed significant improvements in HRQOL scores.ConclusionsFusion to S1/ilium had better sagittal alignment restoration at postoperative week 6 and involved higher PJK rates and greater PJK angles than that to L4/L5. The clinical outcomes and rates of revision surgery and complications were similar between the groups.

Bone graft fusion is a major concern among surgeons after Anterior Cervical Discectomy and Fusion (ACDF) surgery as non-fusion may lead to further physical and drug therapies. The related risk elements of non-fusion of bone graft in ACDF surgery were retrospectively assessed. Patients receiving ACDF operation in our hospital from January 2015 to December 2019 were retrospectively analyzed. According to the criteria, 107 study subjects were recruited with a total of 164 surgical segments. The general information of patients, bone graft materials, imaging parameters, and clinical efficacy was recorded. T-test, chi-square test and binary logistic regression evaluation were employed to explore the risk factors of bone graft nonunion. Low housefield unit (HU) value, diabetes, allogeneic bone, and hydroxyapatite (HA) artificial bone could be risk factors for bone graft fusion in ACDF surgery. Further multivariate analysis was performed and confirmed those related factors of bone graft non-fusion including low HU value (non-fusion rate: 32.53% [27/83], OR = 5.024, p = 0.025), diabetes (non-fusion rate: 53.33% [8/15], OR = 4.776, p = 0.031), allogeneic bone (18.57% [13/70], OR = 3.964, p = 0.046), and artificial bone (68.29% [28/41], OR = 50.550, p < 0.01). By looking at bone graft fusion, selecting autologous iliac bone is an ideal selection to avoid non-fusion of bone graft in ACDF. Diabetes was more important predictor of bone graft nonunion than low HU value. Larger sample size and longer follow-up are required to further confirm these findings in the future. [ABSTRACT FROM AUTHOR]

• Cortical bone trajectory screws and pedicle screws for facet fusion were compared. • Facet fusion rate was >90% with either screw trajectory. • Clinical outcomes were excellent regardless of screw trajectories. • Revision surgery rate was extremely low at the average follow-up of 5 years. • Intraoperative blood loss was significantly less than with pedicle screws. Cortical bone trajectory (CBT) screws have been introduced as an alternative technique for pedicle screw (PS) insertion because they have greater contact with the cortex and a greater uniaxial pullout load than traditional PS. CBT screwing can also minimize muscle dissection. However, CBT screws and traditional PSs have not yet been compared in terms of fusion rates and clinical outcomes for particular operative procedures. This study aimed to assess the fusion rate and clinical outcomes of facet fusion (FF) fixed with CBT screws (CBT-FF) and to compare them with those of FF fixed with percutaneous PS (PPS-FF). Retrospective study. Records of 68 patients who underwent CBT-FF for single-level degenerative lumbar spondylolisthesis (DLS) with at least 1 year of follow-up were retrospectively reviewed. The control group comprised 143 patients who underwent PPS-FF under the same conditions. Computed tomography was performed to confirm fusion. Therapeutic effectiveness was assessed as a clinical outcome using the Japanese Orthopaedic Association Back Pain Evaluation Questionnaire (JOABPEQ), Roland-Morris Disability Questionnaire (RMDQ), and visual analog scale (VAS) preoperatively and 1 year postoperatively. The rate of revision surgery was also calculated. Intraoperative blood loss was measured. Fusion rate, clinical outcomes, revision surgery rate, and intraoperative blood loss of CBT-FF and PPS-FF were compared. The CBT-FF and PPS-FF fusion rates were 91.2% and 90.1%, respectively. The JOABPEQ category scores demonstrated therapeutic effectiveness in 74.5% and 77.1% of the patients for low back pain; the corresponding proportions for walking ability were 84.7% and 89.3%, respectively. No significant differences in therapeutic effectiveness were observed for any category, including the RMDQ and VAS scores for buttock and lower limb pain. Three patients required revision surgery for adjacent segment disease between 6 months and 3.5 years after CBT-FF (revision surgery rate, 4.4%), whereas the revision surgery rate for PPS-FF was 6.3% (9/143 cases). Average intraoperative blood loss was significantly less in the CBT-FF group than in the PPS-FF group. Both procedures were equally useful in terms of fusion rate and clinical outcomes for DLS management. [ABSTRACT FROM AUTHOR]

• This was the first meta-analysis comparing fusion rate of different MCs; • MCs decreased the fusion rate at the 3- and 6-month follow-ups; • MCs-2 and MCs-3 decrease the fusion rate in PLIF. To compare the fusion rates of spinal interbody fusion in patients with modic changes (MCs). This meta-analysis was registered at PROSPERO, and the project number was CRD42024538023. This network meta-analysis was conducted according to the PRISMA 2020 statement. The PubMed, Embase, Web of Science Core Collection, ClinicalTrials.gov and Cochrane Library databases were searched from inception to March 28, 2024 for potential studies. STATA 13.0 and Review Manager 5.3 were used to perform the meta-analysis. Seven studies with a total of 1162 patients or segments assigned to four groups according to MCs grade were identified. The fusion rate in the non-modic changes (NMCs) was significantly greater than that in the MCs at the 3-month (p = 0.0001) and 6-month (p = 0.002) follow-ups. No significant difference was detected in the fusion rate at 12-month (p = 0.34) and final follow-ups (p = 0.41). No significant difference was found in cervical fusion (p = 0.88) or transforaminal lumbar interbody fusion (TLIF) (p = 0.51). The fusion rate of NMCs was significantly greater than that of MCs in posterior lumbar interbody fusion (PLIF) (p < 0.00001). No significant differences were identified among the four groups in the overall comparison, cervical fusion or TLIF subgroups. The fusion rate in the NMCs was significantly greater than that in the MCs-2 and MCs-3 in the PLIF. MCs decreased the fusion rate at the 3- and 6-month follow-ups. MCs-2 and MCs-3 decrease the fusion rate in PLIF. [ABSTRACT FROM AUTHOR]

Objective: Autologous iliac bone is commonly used as a bone graft material to achieve solid fusion in craniocervical junction (CVJ) surgery. However, the developing iliac bone of children is less than ideal as a bone graft material. The matured rib bone of children presents a potential substitute material for iliac bone. The aim of this study was to evaluate the efficacy of autologous rib grafts for craniocervical junction surgery in children. Methods: The outcomes of 10 children with abnormalities of the craniocervical junction who underwent craniocervical junction surgery between January 2020 and December 2022 were retrospectively reviewed. All patients underwent posterior fusion and internal fixation surgery with autologous rib grafts. Pre- and post-operative images were obtained and clinical follow-ups were conducted to evaluate neurological function, pain level, donor site complications, and bone fusion rates. Results: All surgeries were successful. During the 8- to 24-month follow-up period, all patients achieved satisfactory clinical results. Computed tomography at 3–6 months confirmed successful bone fusion and regeneration of the rib defect in all patients with no neurological or donor site complications. Conclusion: Autologous rib bone is a safe and effective material for bone grafting in craniocervical junction fusion surgery for children that can reduce the risks of donor site complications and increase the amount of bone graft, thereby achieving a higher bone fusion rate. [ABSTRACT FROM AUTHOR]

The aim of this systematic review was to investigate the outcomes of knee arthrodesis (KA) after periprosthetic joint infection (PJI) of the knee. Differences in clinical outcomes and complication rates among the intramedullary nailing (IMN), external fixation (EF), and compression plating (CP) procedures were compared. A total of 23 studies were included. Demographics, microbiological data, types of implants, surgical techniques with complications, reoperations, fusion, and amputation rates were reported. A total of 787 patients were evaluated, of whom 601 (76.4%), 166 (21%), and 19 (2.4%) underwent IMN, EF, and CP, respectively. The most common causative pathogen was coagulase-negative Staphylococcus (CNS). Fusion occurred in 71.9%, 78.8%, and 92.3% of the patients after IMN, EF, and CP, respectively, and no statistically significant difference was found. Reinfection rates were 14.6%, 15.1%, and 10.5% after IMN, EF, and CP, respectively, and no statistically significant difference was found. Conversion to amputation occurred in 4.3%, 5%, and 15.8% of patients after IMN, EF, and CP, respectively; there was a higher rate after CP than after EF. The IMN technique is the most common option used for managing PJI with KA. No differences in terms of fusion, reinfection, or conversion-to-amputation rates were reported between IMN and EF. CP is rarely used, and the high amputation rate represents an important limitation of this technique. [ABSTRACT FROM AUTHOR]

Background: Few studies have documented the viability of E. coli-derived recombinant human bone morphogenetic protein-2 (rhBMP-2) in transforaminal lumbar interbody fusion (TLIF). This study aimed to assess the safety and fusion rate of rhBMP-2 in TLIF. Methods: The study was conducted as a prospective, multicenter, single-arm trial, and 30 patients needing one- or two-level TLIF were enrolled. Fusion rate was assessed using the 12-month interbody fusion rate on CT. Postoperative problems, including seroma, radiculitis, and ectopic bone formation, which have been documented as risks associated with rhBMP-2 in prior studies, were recorded. Results: The study demonstrated fusion outcomes in all instances at 52 and 104 weeks post-surgery. Significant improvements were observed in clinical outcomes, with ODI, SF-36, and VAS scores, all achieving statistical significance (p < 0.0001). No perioperative adverse events requiring reoperation were reported, and there were no incidences of seroma, radiculitis, cage migration, grafted bone extrusion, postoperative neurologic deficit, or deep wound infection. Conclusions: The study demonstrates the high safety and efficacy in inducing bone fusion of E. coli-derived rhBMP-2 in TLIF, with a notable absence of adverse postoperative complications. Trial registration: This study protocol was registered at Korea Clinical Research Information Service (number identifier: KCT0004738) on July 2020. [ABSTRACT FROM AUTHOR]

To compare the safety and radiological effectiveness of lumbar interbody fusion with a 3D-printed porous titanium (3D-PPT) cage versus a polyetheretherketone (PEEK) cage for the treatment of lumbar degenerative disease. This study was registered at PROSPERO (CRD42023461511). We systematically searched the PubMed, Embase, and Web of Science databases for related studies from inception to September 3, 2023. Review Manager 5.3 was used to conduct this meta-analysis. The reoperation rate, complication rate, fusion rate, and subsidence rate were assessed using relative risk and 95% confidence intervals. Ten articles reporting 9 studies comparing lumbar interbody fusion with 3D-PPT cages versus PEEK cages for the treatment of lumbar degenerative disease were included. The subsidence rate at the 1-year follow-up in the 3D-PPT cage was significantly lower than that in the PEEK cage. The fusion rate in the 3D-PPT cage was significantly higher than that in the PEEK cage at the 6-month follow-up. No significant difference was identified between the 2 groups at the 12-month follow-up. No significant difference was identified between the 2 groups in terms of the complication rate and reoperation rate. There was a trend toward a lower complication rate and reoperation rate with the 3D-PPT cage. Compared with the PEEK cage, the 3D-PPT cage may be a safer implant. The 3D-PPT cage was associated with a higher fusion rate and lower subsidence rate. The 3D-PPT cage may accelerate the intervertebral fusion process, improve the quality of fusion and prevent the occurrence of subsidence. [ABSTRACT FROM AUTHOR]

Objective: The cortical iliac crest autograft (CICA)/structural allograft (SA) has still been recognized as the gold standard for the ACDF technique for its high degree of histocompatibility and osteoinduction ability though the flourishing and evolving cage development. However, there was no further indication for using CICA/SA in ACDF based on basic information of inpatients. Our operative experience implied that applying CICA/SA has an advantage on faster fusion but not the long-term fusion rate. Therefore, our study aimed to compare the fusion rates between CICA and cage, between SA and cage, and between CICA/CA and cage. Methods: Based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA), a comprehensive literature search of electronic databases including PubMed, Embase, Cochrane Library and Web of Science was conducted to identify these clinical trials that investigated the postoperative 3, 6, 12 and 24 months fusion rates of CICA/structural SA versus cage. Assessment of risk of bias, data extraction and statistical analysis were then carried out by two independent authors with the resolve-by-consensus method. The primary outcome was fusion rate at 3, 6, 12 and 24 months postoperatively. The secondary outcomes were also meta-analyzed such as hardware complications, operative duration and hospitalization time. Our meta-analysis was registered with PROSPERO (Identifier: CRD42022345247). Result: A total of 3451 segments (2398 patients) derived from 34 studies were included after the screening of 3366 articles. The segmental fusion rates of CICA were higher than cages at 3 (P = 0.184, I2 = 40.9%) and 6 (P = 0.147, I2 = 38.8%) months postoperatively, but not 12 (P = 0.988, I2 = 0.0%) and 24 (P = 0.055, I2 = 65.6%) months postoperatively. And there was no significant difference in segmental fusion rates between SA and cage at none of 3 (P = 0.047, I2 = 62.2%), 6 (P = 0.179, I2 = 41.9%) and 12 (P = 0.049, I2 = 58.0%) months after operations. As for secondary outcomes, the CICA was inferior to cages in terms of hardware complications, operative time, blood loss, hospitalization time, interbody height, disk height and Odom rating. The hardware complication of using SA was significantly higher than the cage, but not the hospitalization time, disk height, NDI and Odom rating. Conclusion: Applying CICA has an advantage on faster fusion than using a cage but not the long-term fusion rate in ACDF. Future high-quality RCTs regarding the hardware complications between CICA and cage in younger patients are warranted for the deduced indication. [ABSTRACT FROM AUTHOR]

BackgroundAnterior cervical discectomy and fusion (ACDF) is a common surgery to treat cervical degenerative disc disease. Use of an anterior spacer and plate system (ASPS) results in increased disc height, higher fusion rate, lower subsidence rate, and lower complication rate than a spacer alone.1,2 However, anterior cervical plating is associated with complications, such as dysphagia, plate-screw dislodgment, soft tissue injury, neural injury, and esophageal perforation.3-9 To potentially reduce these drawbacks, integrated spacer and plate (ISP) systems have gained popularity.MethodsFrom November 2009 to October 2013, a total of 84 consecutive patients who underwent 2-level ACDF using ISP or ASPS were reviewed for clinical and radiographic outcomes. Patient-reported visual analog scale (VAS) and Neck Disability Index (NDI) scores, fusion rates, and hardware failure were determined at 1, 3, 6, 12, and 24 months after surgery.ResultsForty-three patients received ISP and 41 patients received ASPS. There were no significant differences in patient demographics between the 2 groups. Perioperative characteristics were similar, except for operative time. Postoperatively, no significant differences in VAS or NDI scores or fusion status were found. At the proximal surgical level only, there was a trend toward an earlier observed radiographic fusion rate in ASPS vs ISP, but this finding was not statistically significant (P = 0.092). One case of long-term dysphagia was reported in each group. Neither group had implant failures up to 2 years.ConclusionsThe ISP system for 2-level ACDF compared to traditional ASPS has comparable clinical and radiographic outcomes up to 2 years postoperatively. There may be a trend toward an earlier observed radiographic fusion in the ASPS group, but there was no difference in long-term dysphagia rate.Clinical relavanceIntegrated spacer and traditional anterior spacer for 2-level ACDF has similar clinical and radiographical outcome.Level of evidence: 4

Abstract Purpose To compare the clinical efficacy of oblique lateral interbody fusion (OLIF) combined with unilateral (UPSF) and bilateral pedicle screw internal fixation (BPSF) in patients with osteoporosis. Methods Clinical data of 57 patients who underwent single-segment OLIF surgery with a clear diagnosis of osteoporosis from December 2018 to May 2021 were retrospectively analyzed, of which 27 patients underwent OLIF + UPSF and 30 patients underwent OLIF + BPSF. Surgical technique-related indexes were recorded, including operative time, operative blood loss and postoperative hospital stay; clinical outcome-related indexes included postoperative complications, Visual analogue scale (VAS) and Oswestry disability index (ODI) at preoperative, 1 week, 1 month, 3 months, and 12 months postoperative follow-up; and imaging outcome-related indexes included the measurement of preoperative and postoperative segmental lordosis (SL), and observation of the degree of cage subsidence and bone graft fusion. Results The surgery was successfully performed in 57 patients, and there was no statistical difference in operative blood loss and postoperative hospital stay between UPSF group and BPSF group (P > 0.05). In terms of operative time, there was a significant difference (UPSF group: 92.30 ± 11.03 min, BPSF group: 119.67 ± 16.41, P 0.05). At 1 year postoperatively, the rate and degree of cage subsidence was higher in the UPSF group than in the BPSF group (P

BackgroundThere currently exists some controversy about the efficacy of oblique lumbar interbody fusion (OLIF) and transforaminal lumbar interbody fusion (TLIF) in the treatment of lumbar degenerative diseases.AimThis study compares the application effects of OLIF and TLIF in lumbar degenerative diseases by reviewing the literature and using meta-analysis.MethodsWe included randomized controlled trials and cohort studies comparing TLIF and OLIF in the treatment of lumbar degenerative diseases. We searched for words such as “intervertebral disc degeneration,” “spinal fusion,” and “lumbar vertebrae” in the PubMed, Embase, and Cochrane Library databases. The search date was set from the establishment date of the database to October 2023. Two authors independently conducted document screening, data abstraction, and qualitative assessment. A meta-analysis was performed and adapted to RevMan5.3 software. The odds ratio (OR), weighted mean difference (WMD), and 95% CI were calculated by adopting a fixed-effect model (FEM) or a random-effect model (REM).ResultsA total of 18 cohort studies were included with 1,550 patients, of whom 806 patients underwent TLIF (TLIF group) and 744 patients underwent OLIF (OLIF group). There were no significant differences found in the fusion rate [OR = 1.58 (0.95, 2.64), P = 0.08], complication rate [OR = 1.25 (0.93, 1.68), P = 0.14], and visual analog scale for back pain (VAS-BP) [WMD = 0.00 (−0.13, 0.14), P = 0.96] between the two groups. Compared with the TLIF group, the OLIF group had a lower Oswestry disability index (ODI) [WMD = −0.62 (−1.03, −0.20), P = 0.003], a higher foramen height (FH) [WMD = 2.03 (1.42, 2.46), P

A variety of different lumbar spinal fusion techniques have been developed. In this study, we review published medical literature highlighting the differences between lumbar interbody fusion techniques with regard to their surgical technique, clinical outcomes, and complications. PubMed, ScienceDirect, and Google Scholar searches were performed for studies published between January 1990 to April 2018 reporting spinal fusion surgery clinical outcomes of at least one fusion technique. Clinical outcomes were extracted and pooled by surgical technique. Chi-squared analyses and Fisher Exact Tests were used to determine differences in rates between groups. PLIF had the highest rate of successful fusion (97% [155/159]) and the lowest rate of complications (4% [6/131]). A chi square analysis revealed a significant difference in fusion success in PLIF compared to PLF (84% [278/330], p <.001). PLIF also had significantly fewer complications compared to PSF (14.7% [251/1709], p =.001), PLF (13.4% [47/351], p =.008), ALIF (14.2% [22/155], p =.008), and LIC (13.9% [47/339], p =.005). Additionally, there were significant differences in the rate of successful fusion when comparing lateral interbody cage (LIC) techniques (p =.041), which include OLIF (100% [63/63]), DLIF (92% [24/26]), and XLIF (87% [67/77]). LIC techniques overall had higher fusion success rates (93.0% [154/166] compared to PLF (p =.01), but a higher rate of complications (14% [47/339]) compared to PLIF (p =.005) and TLIF (6% [17/259], p =.005). Overall, PLF and XLIF have the lowest fusion success rates, and OLIF demonstrated a trend of higher fusion rates among LIC. Techniques that utilized interbody fusion tended to increase the rate of fusion. While interbody fusion techniques offer higher rates of fusion, complication rates also tend to rise with the increase in complexity of the surgical technique, as with OLIF which notably has the highest fusion rate and complication rate. [ABSTRACT FROM AUTHOR]

• The clinical role of crosslink augmentation in PLIF with facetectomy is unclear. • Propensity score-matched comparison with/without a crosslink of 200 patients. • Crosslink augmentation in PLIF with facetectomy provided no observable benefit. We investigated the clinical role of crosslink augmentation during PLIF with total facetectomy. We retrospectively reviewed 376 patients who underwent one- or two-segment PLIF with unilateral or bilateral total facetectomy between January 2017 and March 2022. The patients were categorized into two groups based on whether a crosslink was instrumented or not. Radiological outcome measurements included fusion status and implant failure rates on 12-month postoperative computed tomography. Patient-reported outcome measures included the Numerical Rating Scale for lower back pain, Oswestry Disability Index, and Short Form-12 Physical Component Summary scores, which were assessed preoperatively and at 12 months postoperatively. Surgery-related complications included surgical site infection, symptomatic implant failure, and epidural hematoma. Propensity score matching was performed to compare both groups after adjusting for confounding factors, including baseline and surgical procedural characteristics. A total of 200 cases were included in the propensity score calculation, and one-to-one matching was performed, resulting in 56 pairs with and without a crosslink. The fusion status (88.7 % vs. 85.5 %), screw loosening (14.3 % vs. 14.3 %), cage subsidence (17.9 % vs. 16.1 %), and cage dislodgement (5.4 % vs. 0 %) showed no significant difference between those with and without a crosslink, respectively. No significant differences were observed in the patient-reported outcomes or surgery-related complication rates between the groups. Crosslink augmentation during PLIF with total facetectomy is not recommended because it does not provide any radiological or clinical benefit and is associated with avoidable expenses. [ABSTRACT FROM AUTHOR]

Background and Objectives: Posterior lumbar interbody fusion (PLIF) plays a crucial role in addressing various spinal disorders. The success of PLIF is contingent upon achieving bone fusion, as failure can lead to adverse clinical outcomes. Demineralized bone matrix (DBM) has emerged as a promising solution for promoting fusion due to its unique combination of osteoinductive and osteoconductive properties. This study aims to compare the effectiveness of three distinct DBMs (Exfuse®, Bongener®, and Bonfuse®) in achieving fusion rates in PLIF surgery. Materials and Methods: A retrospective review was conducted on 236 consecutive patients undergoing PLIF between September 2016 and February 2019. Patients over 50 years old with degenerative lumbar disease, receiving DBM, and following up for more than 12 months after surgery were included. Fusion was evaluated using the Bridwell grading system. Bridwell grades 1 and 2 were defined as 'fusion', while grades 3 and 4 were considered 'non-fusion.' Clinical outcomes were assessed using visual analog scale (VAS) scores for pain, the Oswestry disability index (ODI), and the European quality of life-5 (EQ-5D). Results: Fusion rates were 88.3% for Exfuse, 94.3% for Bongener, and 87.7% for Bonfuse, with no significant differences. All groups exhibited significant improvement in clinical outcomes at 12 months after surgery, but no significant differences were observed among the three groups. Conclusions: There were no significant differences in fusion rates and clinical outcomes among Exfuse, Bongener, and Bonfuse in PLIF surgery. [ABSTRACT FROM AUTHOR]

Purpose: To compare the clinical efficacy of oblique lateral interbody fusion (OLIF) combined with unilateral (UPSF) and bilateral pedicle screw internal fixation (BPSF) in patients with osteoporosis. Methods: Clinical data of 57 patients who underwent single-segment OLIF surgery with a clear diagnosis of osteoporosis from December 2018 to May 2021 were retrospectively analyzed, of which 27 patients underwent OLIF + UPSF and 30 patients underwent OLIF + BPSF. Surgical technique-related indexes were recorded, including operative time, operative blood loss and postoperative hospital stay; clinical outcome-related indexes included postoperative complications, Visual analogue scale (VAS) and Oswestry disability index (ODI) at preoperative, 1 week, 1 month, 3 months, and 12 months postoperative follow-up; and imaging outcome-related indexes included the measurement of preoperative and postoperative segmental lordosis (SL), and observation of the degree of cage subsidence and bone graft fusion. Results: The surgery was successfully performed in 57 patients, and there was no statistical difference in operative blood loss and postoperative hospital stay between UPSF group and BPSF group (P > 0.05). In terms of operative time, there was a significant difference (UPSF group: 92.30 ± 11.03 min, BPSF group: 119.67 ± 16.41, P < 0.05). Postoperative VAS and ODI scores exhibited significant improvement (P < 0.05). At the 12 months postoperative follow-up, the VAS and ODI scores in the BPSF group were significantly better than those in the UPS group (P < 0.05). Compared with the preoperative images, the SL was significantly improved in both groups after surgery (P < 0.05). At 6 months postoperatively, the fusion rate in the UPSF group was significantly lower than that in the BPSF group (P < 0.05). At 1 year postoperatively, the fusion rate in the UPSF group was not significantly different from that in the BPSF group (P > 0.05). At 1 year postoperatively, the rate and degree of cage subsidence was higher in the UPSF group than in the BPSF group (P < 0.05). Conclusion: In the long term, OLIF combined with bilateral posterior fixation applied to the osteoporosis patients is superior to OLIF surgery combined with unilateral posterior fixation in terms of clinical and imaging outcomes. It is effective in improving pain relief and functional improvement, accelerating bone graft fusion, and reducing cage subsidence compared with UPSF. [ABSTRACT FROM AUTHOR]

Several minimally invasive lumbar interbody fusion techniques may be used as a treatment for spondylolisthesis to alleviate back and leg pain, improve function and provide stability to the spine. Surgeons may choose an anterolateral or posterior approach for the surgery however, there remains a lack of real-world evidence from comparative, prospective studies on effectiveness and safety with relatively large, geographically diverse samples and involving multiple surgical approaches. To test the hypothesis that anterolateral and posterior minimally invasive approaches are equally effective in treating patients with spondylolisthesis affecting one or two segments at 3-months follow-up and to report and compare patient reported outcomes and safety profiles between patients at 12-months post-surgery. Prospective, multicenter, international, observational cohort study. Patients with degenerative or isthmic spondylolisthesis who underwent 1- or 2-level minimally invasive lumbar interbody fusion. Patient reported outcomes assessing disability (ODI), back pain (VAS), leg pain (VAS) and quality of life (EuroQol 5D-3L) at 4-weeks, 3-months and 12-months follow-up; adverse events up to 12-months; and fusion status at 12-months post-surgery using X-ray and/or CT-scan. The primary study outcome is improvement in ODI score at 3-months. Eligible patients from 26 sites across Europe, Latin America and Asia were consecutively enrolled. Surgeons with experience in minimally invasive lumbar interbody fusion procedures used, according to clinical judgement, either an anterolateral (ie, ALIF, DLIF, OLIF) or posterior (MIDLF, PLIF, TLIF) approach. Mean improvement in disability (ODI) was compared between groups using ANCOVA with baseline ODI score used as a covariate. Paired t -tests were used to examine change from baseline in PRO for both surgical approaches at each timepoint after surgery. A secondary ANCOVA using a propensity score as a covariate was used to test the robustness of conclusions drawn from the between group comparison. Participants receiving an anterolateral approach (n=114) compared to those receiving a posterior approach (n=112) were younger (56.9 vs 62.0 years, p <.001), more likely to be employed (49.1% vs 25.0%, p<.001), have isthmic spondylolisthesis (38.6% vs 16.1%, p<.001) and less likely to only have central or lateral recess stenosis (44.9% vs 68.4%, p=.004). There were no statistically significant differences between the groups for gender, BMI, tobacco use, duration of conservative care, grade of spondylolisthesis, or the presence of stenosis. At 3-months follow-up there was no difference in the amount of improvement in ODI between the anterolateral and posterior groups (23.2 ± 21.3 vs 25.8 ± 19.5, p=.521). There were no clinically meaningful differences between the groups on mean improvement for back- and leg-pain, disability, or quality of life until the 12-months follow-up. Fusion rates of those assessed (n=158; 70% of the sample), were equivalent between groups (anterolateral, 72/88 [81.8%] fused vs posterior, 61/70 [87.1%] fused; p=.390). Patients with degenerative lumbar disease and spondylolisthesis who underwent minimally invasive lumbar interbody fusion presented statistically significant and clinically meaningful improvements from baseline up to 12-months follow-up. There were no clinically relevant differences between patients operated on using an anterolateral or posterior approach. • Real world data from a large global sample of patients with spondylolisthesis. • Clinically significant improvement up to 12-months after minimally invasive fusion. • No clinically relevant differences between anterolateral and posterior approaches. [ABSTRACT FROM AUTHOR]

Interbody cages for spinal fusions are primarily constructed from polyetheretherketone or titanium compositions. However, these crude macroscopic materials pose limitations for improving the rates of bony fusions. The authors aimed to compare the fusion rates and postoperative complications in patients who underwent 2-level or 3-or 4-level anterior cervical discectomy and fusion (ACDF) performed with the use of a novel biomimetic surface titanium cage. A retrospective multicenter study was conducted that included all patients who underwent multilevel ACDF with this cage between January 2017 and April 2021. Patient demographics and procedure-related, radiographic, and postoperative complication data were collected. A total of 124 patients were identified; 69 (55.6%) had a 3-or 4-level fusion and 55 (44.4%) had a 2-level fusion. The demographics of the 2 groups differed significantly only in terms of age (P = 0.01). At 3 months, a significantly higher solid fusion rate was found for 2-level fusions than 3-or 4-level fusions (83.7% vs. 56.3%, P = 0.004); however, significance was lost at 6-months (98.2% vs. 88.4%, respectively; P = 0.08). No patients required posterior supplemental fixation. Transient dysphagia was the only postoperative complication that was significantly increased in the 3-or 4-level fusion group compared to the 2-level group (27.5% vs. 9.1%, P = 0.02). Radiographic and clinical outcomes were equivalent in 3-or 4-level and 2-level ACDFs in which these biomimetic surface titanium cages were used. Furthermore, the use of this technology led to high fusion rates with no requirement for posterior supplemental fusions. [ABSTRACT FROM AUTHOR]

Abstract Background To obtain the complication rate, fusion rate, and revision rate of the lumbar cortical bone trajectory technique and pedicle screw fixation technique in lumbar interbody fusion surgery by single-arm meta-analysis and lay a basis for orthopedic surgeons to select the fixation techniques and perioperative management. Methods PubMed, Ovid Medline, Web of Science, CNKI, and Wanfang databases were searched comprehensively. Data extraction, content analysis, and quality assessment of the literature were performed by two independent reviewers according to the Cochrane Collaboration guidelines using R and STATA software for single-arm meta-analysis. Results The total complication rate of the lumbar cortical bone trajectory technique was 6%, including a hardware complication rate of 2%, ASD (adjacent segment degeneration) rate of 1%, wound infection rate of 1%, dural damage rate of 1%, hematoma rate tending to 0%, fusion rate of 94%, and revision rate of 1%. Lumbar pedicle screw fixation techniques had a total complication rate of 9%, with a hardware complication rate of 2%, ASD rate of 3%, wound infection rate of 2%, dural damage rate of 1%, hematoma rate tending to 0%, fusion rate of 94%, and revision rate of 5%. This study was registered with PROSPERO, CRD42022354550. Conclusion Lumbar cortical bone trajectory was associated with a lower total complication rate, ASD rate, wound infection rate, and revision rate than pedicle screw fixation. The cortical bone trajectory technique reduces the incidence of intraoperative and postoperative complications and can be an alternative in lumbar interbody fusion surgery.

Abstract Background The objective of this prospective randomized monocentric study is to compare the speed and quality of interbody fusion of implanted porous Al2O3 (aluminium oxide) cages with PEEK (polyetheretherketone) cages in ACDF (anterior cervical discectomy and fusion). Materials and methods A total of 111 patients were enrolled in the study, which was carried out between 2015 and 2021. The 18-month follow-up (FU) was completed in 68 patients with an Al2O3 cage and 35 patients with a PEEK cage in one-level ACDF. Initially, the first evidence (initialization) of fusion was evaluated on computed tomography. Subsequently, interbody fusion was evaluated according to the fusion quality scale, fusion rate and incidence of subsidence. Results Signs of incipient fusion at 3 months were detected in 22% of cases with the Al2O3 cage and 37.1% with the PEEK cage. At 12-month FU, the fusion rate was 88.2% for Al2O3 and 97.1% for PEEK cages, and at the final FU at 18 months, 92.6% and 100%, respectively. The incidence of subsidence was observed to be 11.8% and 22.9% of cases with Al2O3 and PEEK cages, respectively. Conclusions Porous Al2O3 cages demonstrated a lower speed and quality of fusion in comparison with PEEK cages. However, the fusion rate of Al2O3 cages was within the range of published results for various cages. The incidence of subsidence of Al2O3 cages was lower compared to published results. We consider the porous Al2O3 cage as safe for a stand-alone disc replacement in ACDF.

Abstract Background As an important part of spinal fusion procedure, the selection of fusion cage size is closely related to the curative effect of the surgery. It mainly depends on the clinical experience of surgeons, and there is still a lack of objective standards. The purpose of this study is to propose the concept of relative intervertebral tension (RIT) for the first time and its grading standards to improve the surgical procedures of lumbar interbody fusion. Methods This retrospective study was conducted from January 2018 to July 2019. A total of 83 eligible patients including 45 men and 38 women with lumbar degenerative disease underwent transforaminal lumbar interbody fusion (TLIF) were included in this study. A total of 151 fusion segments were divided into group A, group B and group C according to the grading standards of RIT. In addition, parameters of intervertebral space angle (ISA), intervertebral space height (ISH), intervertebral space foramen (IFH), fusion rates, cage-related complications and cage heights were also compared among the three groups. Results The ISA in group A was the smallest among three groups in contrast with group C with largest ISA at the final follow-up(P 0.05), and a certain correlation between ISH and RIT was also observed. Conclusions The concept of RIT and the application of its clinical grading standards could simplify the surgical procedures of spinal fusion and reduce cage-related complications.

A CaO-SiO2-P2O5-B2O3 bioactive glass-ceramic (BGS-7) spacer provides high mechanical stability, produces a chemical bond to the adjacent endplate, and facilitates fusion after spine surgery. This prospective, randomized, single-blind, non-inferiority trial aimed to evaluate the radiographic outcomes and clinical efficacy of anterior cervical discectomy and fusion (ACDF) using a BGS-7 spacer for treating cervical degenerative disorders. Thirty-six patients underwent ACDF using a BGS-7 spacer (Group N), and 40 patients underwent ACDF using polyetheretherketone (PEEK) cages filled with a mixture of hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP) for the treatment of cervical degenerative disorders. The spinal fusion rate was assessed 12 months postoperatively using three-dimensional computed tomography (CT) and dynamic radiographs. Clinical outcomes included patient-reported outcome measures, visual analog scale scores for neck and arm pain, and scores from the neck disability index (NDI), European Quality of Life-5 Dimensions (EQ-5D), and 12-item Short Form Survey (SF-12v2). All participants were randomly assigned to undergo ACDF using either a BGS-7 spacer or PEEK cage filled with HA and β-TCP. The primary outcome was the fusion rate on CT scan image at 12 months after ACDF surgery based on a per-protocol strategy. Clinical outcomes and adverse events were also assessed. The 12-month fusion rates for the BGS-7 and PEEK groups based on CT scans were 81.8% and 74.4%, respectively, while those based on dynamic radiographs were 78.1% and 73.7%, respectively, with no significant difference between the groups. There were no significant differences in the clinical outcomes between the two groups. Neck pain, arm pain, NDI, EQ-5D, and SF-12v2 scores significantly improved postoperatively, with no significant differences between the groups. No adverse events were observed in either group. In ACDF surgery, the BGS-7 spacer showed similar fusion rates and clinical outcomes as PEEK cages filled with HA and β-TCP. [ABSTRACT FROM AUTHOR]

Abstract Background The use of platelet-rich plasma has been increasing in spinal fusion surgery. However, the efficacy of platelet-rich plasma in lateral lumbar interbody fusion is unclear. In Japan, Affinos,® (Kuraray Co., Tokyo, Japan), a β-tricalcium phosphate artificial bone, has been increasingly used for spinal fusion. The purpose of this trial is to demonstrate whether Affinos® impregnated with platelet-rich plasma can achieve a higher fusion rate and better clinical outcomes than Affinos® alone. Methods The current study is a prospective randomized controlled trial. This trial will include consecutive patients scheduled for lateral lumbar interbody fusion. An intervertebral cage for lateral lumbar interbody fusion has two spaces for bone grafts. As a consequence, two bone grafts are inserted at each intervertebral level. In this study, an artificial bone with platelet-rich plasma will be inserted into one space, and an artificial bone without platelet-rich plasma will be inserted into the other space. We will compare the fusion rates between the bone grafts with and without platelet-rich plasma. Our primary endpoint will be the interbody fusion rate at 1 year after surgery. Discussion This trial will verify the efficacy of platelet-rich plasma with Affinos® for bony fusion in lateral lumbar interbody fusion. It will also provide substantial evidence for the effectiveness and safety of platelet-rich plasma in spinal fusion surgery. Trial registration Japan Registry of Clinical Trials (jRCT) jRCTb032200199 . First registered on 13 November 2020. jRCT is approved as a member of the Primary Registry Network of WHO ICTRP.

Objective Three-dimensional (3D)-printed titanium implants have been developed recently, but the utility is not yet proven. The aim of this study was to compare 3D-printed titanium and polyetheretherketone (PEEK) implants after minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF). Methods Between October 2018 and September 2021, we retrospectively analyzed 83 patients who underwent single-level MIS-TLIF (3D-printed titanium, 40; PEEK, 43). Radiologic parameters were assessed with x-ray and computed tomography (CT) at postoperative 1 week, 6 months, and 1 year. Clinical status was evaluated using Oswestry Disability Index, visual analogue scale score, and Bridwell fusion grading was assessed on 6-month and 1-year postoperative CT. Results There were no differences between the 2 groups in demographics and clinical outcomes. At 1-year of follow-up, the reported 3D-printed titanium fusion grades were grade I: 77.5% (31 patients), grade II: 17.5% (7 patients), and grade III: 5% (2 patients). The PEEK fusion grades were grade I: 51.2% (22 patients), grade II: 41.9% (18 patients), and grade III: 7.0% (3 patients). For overall fusion rate (grade I + II), there was no difference between the 2 cages (95.0% vs. 93.0%, p=0.705), but grade I was reported at a higher incidence in 3D-printed titanium than PEEK (77.5% vs. 51.2%, p=0.013). There was no difference between cages based on subsidence and complications. Conclusion There were no significant differences in the overall fusion rate for MIS-TLIF surgery between 3D-printed titanium and PEEK, but the fusion grade was better in 3D-printed titanium than in PEEK. Long-term follow-up is required to verify the effectiveness.

BackgroundOdontoid fractures account for 15%–20% of cervical injuries. Although the operation methods vary in different types, the superiority of overall outcomes of the anterior approach (AA) and posterior approach (PA) in treating odontoid fractures still remains controversial. Thus, a meta-analysis was performed comparing AA and PA for these fractures.MethodsThe relevant studies were searched in PubMed/MEDLINE, Cochrane Library, EMBASE, China Biological Medicine (CBM), and Wanfang Database from the onset of conception to June 2022. Prospective or retrospective comparative studies on AA and PA for odontoid fractures were screened, referring to fusion rates (primary outcomes), complications, and postoperative mortality rates. A meta-analysis of the primary outcomes and a systematic review of other outcomes were performed; the procedure was conducted with Review Manager 5.3.ResultsTwelve articles comrising 452 patients were included, and all publications were retrospective cohort studies. The average postoperative fusion rate was 77.5 ± 17.9% and 91.4 ± 13.5% in AA and PA, respectively, with statistical significance [OR = 0.42 (0.22, 0.80), P = 0.009]. Subgroup analysis showed a difference in fusion rates between AA and PA in the elderly group [OR = 0.16 (0.05, 0.49), P = 0.001]. Five articles referred to postoperative mortality, and the mortality rates of AA (5.0%) and PA (2.3%) showed no statistical difference (P = 0.148). Nine studies referred to complications, with a rate of 9.7%. The incidence of complications in AA and PA groups was comparable (P = 0.338), and the incidence of nonfusion and complications was irrelevant. The prevalent cause of death was myocardial infarction. The time and segmental movement retention of AA were possibly superior to those of PA.ConclusionAA may be superior in regard to operation time and motion retention. There was no difference in complications and mortality rates between the two approaches. The posterior approach would be preferred in consideration of the fusion rate.

Background: To obtain the complication rate, fusion rate, and revision rate of the lumbar cortical bone trajectory technique and pedicle screw fixation technique in lumbar interbody fusion surgery by single-arm meta-analysis and lay a basis for orthopedic surgeons to select the fixation techniques and perioperative management. Methods: PubMed, Ovid Medline, Web of Science, CNKI, and Wanfang databases were searched comprehensively. Data extraction, content analysis, and quality assessment of the literature were performed by two independent reviewers according to the Cochrane Collaboration guidelines using R and STATA software for single-arm meta-analysis. Results: The total complication rate of the lumbar cortical bone trajectory technique was 6%, including a hardware complication rate of 2%, ASD (adjacent segment degeneration) rate of 1%, wound infection rate of 1%, dural damage rate of 1%, hematoma rate tending to 0%, fusion rate of 94%, and revision rate of 1%. Lumbar pedicle screw fixation techniques had a total complication rate of 9%, with a hardware complication rate of 2%, ASD rate of 3%, wound infection rate of 2%, dural damage rate of 1%, hematoma rate tending to 0%, fusion rate of 94%, and revision rate of 5%. This study was registered with PROSPERO, CRD42022354550. Conclusion: Lumbar cortical bone trajectory was associated with a lower total complication rate, ASD rate, wound infection rate, and revision rate than pedicle screw fixation. The cortical bone trajectory technique reduces the incidence of intraoperative and postoperative complications and can be an alternative in lumbar interbody fusion surgery. [ABSTRACT FROM AUTHOR]

Purpose: This paper sets out to analyse mobility changes in segments adjacent to the operated segment. Additionally, it investigates the relationship between the degree of fusion in the operated disc space and mobility changes in the adjacent segments. Methods: In total, 170 disc spaces were operated on in 104 consecutive patients qualified for one- or two-level surgery. The degree of mobility of segments directly above and below the implant insertion site was calculated. Measurements were performed the day before the surgery and 12 months post-surgery. Functional (flexion and extension) radiographs of the cervical spine and CT scans obtained 12 months post-surgery were used to evaluate the fusion status. The results were subjected to statistical analysis. Results: Statistically significant increase in mobility was recorded for the segments situated immediately below the operative site, with a mean change in mobility of 1.7 mm. Complete fusion was demonstrated in 101 cases (71.1%), and partial fusion in 43 cases (29.9%). In the complete fusion subgroup, the ranges of both flexion and extension in the segments directly below the operative site were significantly greater than those in the partial fusion (pseudoarthrosis) subgroup. Conclusion: The mobility of the adjacent segment below the implant insertion site was significantly increased at 12 months post-ACDF surgery. The range of this compensatory hypermobility was significantly greater in patients with complete fusion at the ACDF site than in cases of pseudoarthrosis. Implant subsidence was not associated with mobility changes in the segments directly above or directly below the site of ACDF surgery. [ABSTRACT FROM AUTHOR]

Background: As an important part of spinal fusion procedure, the selection of fusion cage size is closely related to the curative effect of the surgery. It mainly depends on the clinical experience of surgeons, and there is still a lack of objective standards. The purpose of this study is to propose the concept of relative intervertebral tension (RIT) for the first time and its grading standards to improve the surgical procedures of lumbar interbody fusion. Methods: This retrospective study was conducted from January 2018 to July 2019. A total of 83 eligible patients including 45 men and 38 women with lumbar degenerative disease underwent transforaminal lumbar interbody fusion (TLIF) were included in this study. A total of 151 fusion segments were divided into group A, group B and group C according to the grading standards of RIT. In addition, parameters of intervertebral space angle (ISA), intervertebral space height (ISH), intervertebral space foramen (IFH), fusion rates, cage-related complications and cage heights were also compared among the three groups. Results: The ISA in group A was the smallest among three groups in contrast with group C with largest ISA at the final follow-up(P < 0.05). The group A presented the smallest ISH and IFH values(P < 0.05), compared with group B with the largest ISH and IFH values(P < 0.05). These two parameters in the group C were in-between. The fusion rates of group A, group B and group C were 100%, 96.3% and 98.8% at the final follow-up, respectively. No statistical difference in fusion rates and cage-related complications occurred among the three groups(P > 0.05), and a certain correlation between ISH and RIT was also observed. Conclusions: The concept of RIT and the application of its clinical grading standards could simplify the surgical procedures of spinal fusion and reduce cage-related complications. [ABSTRACT FROM AUTHOR]

Background: The objective of this prospective randomized monocentric study is to compare the speed and quality of interbody fusion of implanted porous Al2O3 (aluminium oxide) cages with PEEK (polyetheretherketone) cages in ACDF (anterior cervical discectomy and fusion). Materials and methods: A total of 111 patients were enrolled in the study, which was carried out between 2015 and 2021. The 18-month follow-up (FU) was completed in 68 patients with an Al2O3 cage and 35 patients with a PEEK cage in one-level ACDF. Initially, the first evidence (initialization) of fusion was evaluated on computed tomography. Subsequently, interbody fusion was evaluated according to the fusion quality scale, fusion rate and incidence of subsidence. Results: Signs of incipient fusion at 3 months were detected in 22% of cases with the Al2O3 cage and 37.1% with the PEEK cage. At 12-month FU, the fusion rate was 88.2% for Al2O3 and 97.1% for PEEK cages, and at the final FU at 18 months, 92.6% and 100%, respectively. The incidence of subsidence was observed to be 11.8% and 22.9% of cases with Al2O3 and PEEK cages, respectively. Conclusions: Porous Al2O3 cages demonstrated a lower speed and quality of fusion in comparison with PEEK cages. However, the fusion rate of Al2O3 cages was within the range of published results for various cages. The incidence of subsidence of Al2O3 cages was lower compared to published results. We consider the porous Al2O3 cage as safe for a stand-alone disc replacement in ACDF. [ABSTRACT FROM AUTHOR]

Objective: Anterior bone loss (ABL) was considered as a non-progressive process secondary only to motion-preserving implant and has been noticed recently in cervical disk replacement (CDR) let alone patients with anterior cervical diskectomy and fusion (ACDF). Our purpose is to reveal this unnoticed phenomenon in ACDF and further explore its clinical and radiological outcomes. Methods: A total of 77 patients underwent ACDF with a minimum follow-up of at least one year were retrospectively reviewed. The average follow-up time was 22.51 ± 16.31 months. There were 50 patients in group A with ABL, while there were 27 patients in group B without ABL. ABL was measured and classified into four grades according to Kieser's methods. Clinical evaluation, radiological parameters and fusion rate were recorded. Results: The incidence of bone ABL was 64.9% of Zero-P and 55.2% of endplates. The incidence of upper and lower endplates was 61% and 49%, respectively, and such difference was not significant. Mild ABL occurred in 22%, moderate ABL in 38% and severe ABL of 40% patients underwent ACDF with ABL. ABL would not affect both clinical outcomes and fusion rate. However, ABL would result in a higher incidence of subsidence. Conclusion: ABL should be considered as a common phenomenon that both CDR and ACDF owned a non-progressive process which confined in one year. ABL would result in a higher incidence of subsidence. Luckily, this phenomenon does not have an effect on postoperative clinical and fusion rate. [ABSTRACT FROM AUTHOR]

Study Design: Retrospective case-control study. Objectives: This study aims to present the clinical and radiographical outcomes of the titanium-polyetheretherketone (Ti/PEEK) composite cage compared to those of the standard PEEK cage in patients receiving minimally invasive transforaminal lumbar interbody fusion (MI-TLIF). Methods: Patients receiving 1 level MI-TLIF between October 2015 and October 2017 were included with a minimum of 2-year follow-up. The patients were segregated into 2 groups; Ti/PEEK group and PEEK group. Each patient was propensity-matched using preoperative age, sex, and body mass index. Early fusion rate was evaluated by computed tomography at postoperative 6 months. Clinical outcomes were assessed using the visual analog scale (VAS) and Oswestry Disability Index (ODI) scores. Results: After matching, there were 27 patients included in each group. The demographics, diagnosis, and surgical details were not significantly different between the 2 groups. The 6-month rate was 88.9% in Ti/PEEK group. The fusion rate and cage subsidence rate had no difference between the 2 groups. The complication rate in the Ti/PEEK group was comparable to that in the PEEK group. There was no difference in VAS and ODI scores during a 2-year follow-up period. Conclusions: The use of Ti/PEEK composite cage was as safe and effective as the use of PEEK cage in MI-TLIF. The 6-month fusion rate was 88.9%. Our finding revealed comparable clinical results for surgeons using Ti/PEEK composite cages in MI-TLIF compared to those using the PEEK cage. [ABSTRACT FROM AUTHOR]

Background and Objectives: Posterior lumbar interbody fusion (PLIF) plays a crucial role in addressing various spinal disorders. The success of PLIF is contingent upon achieving bone fusion, as failure can lead to adverse clinical outcomes. Demineralized bone matrix (DBM) has emerged as a promising solution for promoting fusion due to its unique combination of osteoinductive and osteoconductive properties. This study aims to compare the effectiveness of three distinct DBMs (Exfuse®, Bongener®, and Bonfuse®) in achieving fusion rates in PLIF surgery. Materials and Methods: A retrospective review was conducted on 236 consecutive patients undergoing PLIF between September 2016 and February 2019. Patients over 50 years old with degenerative lumbar disease, receiving DBM, and following up for more than 12 months after surgery were included. Fusion was evaluated using the Bridwell grading system. Bridwell grades 1 and 2 were defined as ‘fusion’, while grades 3 and 4 were considered ‘non-fusion.’ Clinical outcomes were assessed using visual analog scale (VAS) scores for pain, the Oswestry disability index (ODI), and the European quality of life-5 (EQ-5D). Results: Fusion rates were 88.3% for Exfuse, 94.3% for Bongener, and 87.7% for Bonfuse, with no significant differences. All groups exhibited significant improvement in clinical outcomes at 12 months after surgery, but no significant differences were observed among the three groups. Conclusions: There were no significant differences in fusion rates and clinical outcomes among Exfuse, Bongener, and Bonfuse in PLIF surgery.

Objective. To analyze significance of the influence of various factors on the fusion rate in patients with isthmic spondylolisthesis. Material and Methods. A retrospective monocenter study included data from 41 patients aged 18 years and older with isthmic spondylolisthesis who underwent transforaminal interbody fusion with cage using a four-screw rigid transpedicular fixation system. The influence of potential risk factors on the fusion rate was studied. Results. A univariate analysis showed that obesity (p = 0.037) and the use of non-steroidal anti-inflammatory drugs (NSAIDs) for more than three months (p = 0.007) significantly affect the formation of a bone block. When compiling a logistic regression model, it was found that a combination of obesity, smoking, and the use of NSAIDs for more than three months significantly worsens the prognosis of bone block formation (p = 0.007; R2N = 0.405; AUC = 0.850). Conclusion. The study showed that the absence of bone block formation in patients with isthmic spondylolisthesis may be associated with smoking, obesity, and the use of NSAIDs for more than three months. Keeping these factors in mind and trying to minimize their presence can help ensure better radiographic outcomes after surgery.

Spondylolisthesis changes the pelvic morphology and sagittal spinopelvic alignment with abnormality compared to individuals with similar pelvic morphology. There are many treatment options including a combination of decompression and fusion. In spondylolisthesis patients with high-grade spondylolisthesis, bone to bone contact (closed intradiscal space), and high-grade disc degeneration with disc collapse, fusion is challenging. From 2011 through 2020, an analysis of L5-S1 spondylolisthesis patients who had L5-S1 transdiscal screw fixation with a minimum follow-up of 2 years was performed. Radiological evaluation and clinical measures were compared preoperatively and postoperatively. Postoperative complications were analyzed. Also, L5-S1 degree fusion was analyzed using a computed tomography scan. Eight patients of L5-S1 spondylolisthesis with a mean follow-up of 69 (25–122) months. All patients were female; the average age was 58 (43–78) years. 4 patients presented with high-grade spondylolisthesis (Meyerding grade III). Among the patients, 3 patients were undergoing revision surgery. Only 5 patients had interbody fusion for their adjacent levels. In the postoperative follow-up, none of the patients had neurological deficits. Radiological evaluations of L5-S1 level showed fusion in all patients. Only 1 patient had rod failure and was advised for revision surgery. L5-S1 transdiscal screw fixation may provide a satisfactory rigid fixation and fusion at the L5-S1 level in cases of spondylolisthesis. This technique requires a surgeon's experience. Despite the challenge of this technique, it can provide a safe option for acquiring rigid stabilization. [ABSTRACT FROM AUTHOR]

Purpose: The CaO-SiO2-P2O5-B2O3 glass–ceramic (BGS-7) spacer is a recently developed spacer that shows chemical bonding to bone with high mechanical stability. Further, this spacer achieves similar results to those of titanium cages. However, evidence regarding the advantages of the BGS-7 spacer is weak compared to polyetheretherketone (PEEK) cage. A randomized controlled trial is therefore warranted. The purpose of this study was to compare the radiographic and clinical efficacies and safety of the BGS-7 spacer compared to those of the PEEK cage in patients who underwent posterior lumbar interbody fusion (PLIF). Methods: The 54 participants who required one- or two-level PLIF due to lumbar degenerative disorders were randomly assigned to receive a BGS-7 spacer or PEEK cage. Visual analog scale (VAS), Oswestry Disability Index (ODI), European Quality of Life-5 Dimensions (EQ-5D), and painDETECT score were evaluated before surgery and at 3, 6, and 12 months after surgery. The fusion rate, degree of osteolysis, cage migration, and subsidence around the cage (spacer) were evaluated on computer tomography (CT) images at 12 months after surgery. Results: The 12-month fusion rates were 77.8% in the BGS-7 spacer group and 81.0% in the PEEK cage group, with no significant difference (p = 0.807). The result regarding the non-inferiority of BGS-7 spacer was inconclusive. The linear mixed model showed no significant intervention effect in VAS, ODI, EQ-5D, and painDETECT score at the 3-, 6-, or 12-month follow-up. In addition, we found no significant between-group differences in the extent of osteolysis, spacer migration. However, the subsidence around the cage was significantly lower in the BGS-7 spacer group. Conclusions: This trial found similar fusion rates, and clinicoradiographic outcomes between the BGS-7 spacer and PEEK cage for PLIF. However, the non-inferiority was inconclusive. Safety concerns regarding fracture and migration of the BGS-7 spacer must be considered. Thus, the BGS-7 spacer design for PLIF surgery should be modified before further clinical use. [ABSTRACT FROM AUTHOR]

Study design: This is a retrospective study. Objective: Implant nonfusion is an important prognostic factor for patients after anterior cervical discectomy and fusion (ACDF). This study aimed to investigate endplate-specific pseudarthrosis after ACDF, to determine if the rate of fusion is inferior in the lower endplate, and to identify any differences in clinical and radiological results. Summary of background data: Research comparing each endplate on which the endplate affects nonfusion is limited. Methods: We analyzed 71 patients with 142 total spinal levels who underwent double-level ACDF (C4-5-6 and C5-6-7) with an allograft and plate at our hospital between January 2012 and December 2018. Fusion grades were assessed using computed tomography and the Bridwell fusion grade system at 1 year postoperatively. Radiological parameters were obtained from lateral cervical radiographs collected preoperatively and at 1 month and 1 year after surgery. Results: There was no difference in fusion between the C4-5-6 and C5-6-7 ACDF procedures, but the fusion rate and Bridwell fusion grade at the caudal surgery level were lower than those at the cranial surgery level (93 vs. 79%, p < 0.001). The lower endplate of the caudal fusion level showed the most common pseudarthrosis (18 of 71 [25%]). There was no difference in radiological parameters and clinical outcomes between the fusion and pseudarthrosis groups. Conclusion: In double-level ACDF procedures, the nonfusion rate was higher at the caudal fusion levels, especially at the lower endplates of the caudal fusion levels. [ABSTRACT FROM AUTHOR]

Objective This study aimed to compare the fusion rate of polyetheretherketone (PEEK) and titanium-coated PEEK (Ti-PEEK) cages in transforaminal lumbar interbody fusion (TLIF). Methods The patient groups that underwent TLIF using PEEK and Ti-PEEK cages were identified and matched for age, sex, and whether the lumbar spine surgery was performed more than once using propensity scores. The rate of three-month postoperative vertebral endplate cyst sign (VECS), which was reported as a predictor of pseudoarthrosis at one year postoperatively, and the one-year and two-year postoperative fusions between the two groups were statistically compared. Results There were 34 patients (12 men and 22 women) in the PEEK group with a mean age of 69.8 ± 8.2 years and 36 intervertebral discs; there were 30 patients (11 men and 19 women) in the Ti-PEEK group with a mean age of 70.3 ± 9.6 years and 36 intervertebral discs. The operated levels were two discs (5.6%) in L2/3, four (11.1%) in L3/4, 21 (58.3%) in L4/5, and nine (25.0%) in L5/S in the PEEK group and were one (2.8%) in L3/4, 24 (66.7%) in L4/5, and 11 (30.6%) in L5/S in the Ti-PEEK group (P = 0.31). The frequencies of positive VECS at three months postoperatively were four discs (11.1%) in the PEEK group and five (13.9%) in the Ti-PEEK group, with no significant difference (P = 0.72). Bone fusion rates at one year and two years postoperatively were 26 (72.2%) and 28 (77.8%), respectively, in the PEEK group, and 28 (77.8%) and 32 (88.9%), respectively, in the Ti-PEEK group, with no statistically significant difference (P = 0.59 at one year and P = 0.21 at two years). Among the five cases of positive VECS in the Ti-PEEK group, two cases (40%) had bone fusion at one year postoperatively around the cage but not through the cage. Conclusion There was no significant difference in the rate of bone fusion or VECS after TLIF between the PEEK and Ti-PEEK groups. Positive VECS is more appropriate for a finding of no bone fusion through the cage at one year postoperatively than for a finding that predicts pseudoarthrosis., Competing Interests: Human subjects: Consent for treatment and open access publication was obtained or waived by all participants in this study. Institutional Review Board (IRB) of Shiga General Hospital issued approval 220512-01. Animal subjects: All authors have confirmed that this study did not involve animal subjects or tissue. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work., (Copyright © 2025, Masamoto et al.)

Background: The use of platelet-rich plasma has been increasing in spinal fusion surgery. However, the efficacy of platelet-rich plasma in lateral lumbar interbody fusion is unclear. In Japan, Affinos,® (Kuraray Co., Tokyo, Japan), a β-tricalcium phosphate artificial bone, has been increasingly used for spinal fusion. The purpose of this trial is to demonstrate whether Affinos® impregnated with platelet-rich plasma can achieve a higher fusion rate and better clinical outcomes than Affinos® alone.Methods: The current study is a prospective randomized controlled trial. This trial will include consecutive patients scheduled for lateral lumbar interbody fusion. An intervertebral cage for lateral lumbar interbody fusion has two spaces for bone grafts. As a consequence, two bone grafts are inserted at each intervertebral level. In this study, an artificial bone with platelet-rich plasma will be inserted into one space, and an artificial bone without platelet-rich plasma will be inserted into the other space. We will compare the fusion rates between the bone grafts with and without platelet-rich plasma. Our primary endpoint will be the interbody fusion rate at 1 year after surgery.Discussion: This trial will verify the efficacy of platelet-rich plasma with Affinos® for bony fusion in lateral lumbar interbody fusion. It will also provide substantial evidence for the effectiveness and safety of platelet-rich plasma in spinal fusion surgery.Trial Registration: Japan Registry of Clinical Trials (jRCT) jRCTb032200199 . First registered on 13 November 2020. jRCT is approved as a member of the Primary Registry Network of WHO ICTRP. [ABSTRACT FROM AUTHOR]

Several viruses have the ability to form large multinucleated cells known as syncytia. Many properties of syncytia and the role they play in the evolution of a viral infection are not well understood. One basic question that has not yet been answered is how quickly syncytia form. We use a novel mathematical model of cell-cell fusion assays and apply it to experimental data from SARS-CoV-2 fusion assays to provide the first estimates of virus-mediated cell fusion rate. We find that for SARS-CoV2, the fusion rate is in the range of 6 × 10−4–12×10−4/h. We also use our model to compare fusion rates when the protease TMPRSS2 is overexpressed (2–4 times larger fusion rate), when the protease furin is removed (one third the original fusion rate), and when the spike protein is altered (1/10th the original fusion rate). The use of mathematical models allows us to provide additional quantitative information about syncytia formation. • A mathematical model is used to analyze SARS-CoV-2 cell-cell fusion assays. • This allows us to estimate the virus-mediated fusion rate for the first time. • Estimates are used to quantify the effect of TMPRSS2 and furin on cell fusion. • Removal of the spike cleavage site causes a ten-fold reduction in fusion rate. [ABSTRACT FROM AUTHOR]

Abstract Background Autologous bone has been used for posterior lumbar intervertebral fusion (PLIF). However, harvesting autologous bone graft is associated with donor site complications. We previously developed a hydroxyapatite/collagen (HAp/Col) composite as an osteoconductive artificial bone, characterized by having a highly porous structure with sponge‐like elasticity. This study aims to investigate the effectiveness of HAp/Col composite with bone marrow aspirate (BMA) as a graft substitute in PLIF for the treatment of lumbar spinal diseases. Methods This study prospectively investigated patients who received one-level PLIF. For the interbody fusion, two titanium cages were inserted. On the one side of interbody space, HAp/Col composite incorporated with BMA filling the titanium cage was grafted. On the other side, local bone graft (LBG) harvested during decompressive laminotomy was grafted and then one-level instrumentation using pedicle screws was performed. The target levels were at L2/3 in 2 cases, L3/4 in 3 cases, L4/5 in 36 cases, and L5/S in 5 cases. We evaluated clinical symptoms and radiological outcomes of 46 patients and compared the fusion status of HAp/Col composite with that of LBG. Results The 1-year postoperative CT evaluation demonstrated that, in the HAp/Col, a complete fusion was observed in 38 patients (82.6%), whereas in the LBG, a complete fusion was observed in 35 patients (76.1%). There were no statistical differences between the HAp/Col and LBG. In the HAp/Col, incomplete fusion was observed in five patients (10.9%) and non-fusion in two patients (4.3%), and in the LBG, incomplete fusion was observed in nine patients (19.6%) and non-fusion in two patients (4.3%). At 2 years after the surgery, complete fusion increased to 44 patients (95.7%) in the HAp/Col and 41 patients (89.1%) in the LBG. There were no significant differences in the clinical scores for lumbar spine between patients with fusion and non-fusion. Conclusions The HAp/Col composite with BMA in the titanium cage can be effectively used as an alternative to conventional autologous LBG for intervertebral spinal fusion. Trial registration University hospital Medical Information Network, UMIN000045010, July 30th, 2021, Retrospectively registered, https://www.umin.ac.jp/english/ .