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Choosing between screw-retained and cement-retained restorations in the esthetic zone may significantly impact the restorative contour. This study analyzes the effect of facial-palatal implant positioning on the facial emergence angle of implant restorations in the anterior maxilla. A total of 133 maxillary anterior implant cases were captured with intraoral scans and used to create digital prosthetic designs. The restoration facial emergence angle and the implant depth were determined using images at the midfacial cross section. Simple logistic and linear regression models were used to analyze the interrelation between the emergence angle, depth, and retention methods. The average facial emergence angle for all restorations in this study was 34.4 degrees. A significant difference in emergence angle was found between screw-retained and cement-retained groups, with averages of 37.3 degrees and 27.9 degrees, respectively. There was no difference in the mean depth between the two groups. A strong negative linear relationship between depth and emergence angle was seen for the screw-retained group. Overall, implant positioning in the anterior maxilla has a significant influence on emergence angle. Facial emergence angle is significantly greater for implants in a screw-retained position. This may be partially alleviated by deeper implant placement. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the effects of sinus membrane stabilization (via suturing) and dental implant placement on the endo-sinus bone formation in lateral sinus elevations performed without grafting. Materials and Methods: Maxillary sinus elevation surgery using the lateral approach was performed bilaterally on 30 New Zealand white rabbits. The maxillary sinus areas were divided into control and test groups. In the control group, a titanium screw was placed after sinus membrane elevation; in the test group, the sinus membrane was sutured to the lateral walls, and a titanium screw was placed in the center of the alveolar crest. The subjects were sacrificed at 4 and 8 weeks. Then samples were collected, and a microcomputed tomography (micro-CT) analysis was performed. In addition, the volume of newly formed bone, percentage of osseointegration, sinus volume, residual bone height, and implant protrusion length were measured using micro-CT analysis. Results: The sinus volume, volume of newly formed bone, and percentage of osseointegration in the test group were significantly higher than in the control group at 4 weeks (P = .01, P = .04, P = .02, respectively). While the volume of newly formed bone was 17.1 ± 3.08 mm3 in the control group, it was 26.9 ± 14.26 mm3 in the test group at 4 weeks. The volume of newly formed bone significantly decreased from 26.9 ± 14.26 mm3 to 17 ± 3.66 mm3 at 8 weeks (P = .02). No significant difference in residual bone height was found at 4 and 8 weeks (P = .07). No significant difference in implant protrusion length was found between the control and test groups (P = .18). Protrusion length and new bone formation in the sinus showed a negative relationship (P = .01). Conclusions: Suturing the sinus membrane to the lateral sinus wall is an effective approach for increasing osseointegration, bone volume, and sinus volume in the short term. A slow-absorbing suture material can be used to maintain sinus and bone volumes in the long term. [ABSTRACT FROM AUTHOR]

Dental implants are commonly used to replace missing single teeth. However, esthetic rehabilitation of an adjacent tooth may also be required due to diastemas, crowding, or existing large direct restorations to improve the final esthetic outcome. With the advancements in ceramics and bonding techniques, minimally invasive esthetic approaches have become viable for compromised spacing issues. This case report describes a dental technique for the esthetic rehabilitation of compromised anterior spacing with a customized zirconia implant abutment at a maxillary central incisor site and a partial ceramic veneer bonded to the adjacent central incisor. [ABSTRACT FROM AUTHOR]

Despite the various treatments proposed with barrier membranes, one of the main challenges for guided bone regeneration (GBR) is maintaining space for large defects and ensuring an adequate blood supply. The presented feasibility case series aims to introduce an original titanium frame (TF) design, customized for each defect, as a modification of well-known principles and materials for GBR to achieve an enhanced and more predictable horizontal and vertical bone augmentation. Three patients with significant horizontal defects were treated with pre-trimmed TFs to create needed space, and then a 50/50 mixture of autograft and bovine xenograft was placed and covered with a collagen membrane. After 8 months of healing, the sites were reopened, and the titanium screws were removed with the frame. An average of 8.0 ± 1.0 mm of horizontal and 3.0 ± 0.0 mm of vertical bone gain were achieved at the time of reentry and implant placement surgery. Bone core biopsy sample was obtained during the implant placement. Histomorphometric analysis revealed that 42.8% of the sample was new vital bone, 18.8% was residual bone graft particles, and 38.4% was bone marrow-like structures. After 3 to 4 months from implant placement, the implants were restored with provisional crowns and then finalized with zirconia screw-retained crowns. This case series suggests that GBR utilizing TFs with or without collagen membranes can be considered a suitable approach for horizontal and vertical bone augmentation. However, based on only three reported cases, the results should be carefully interpreted. [ABSTRACT FROM AUTHOR]

Objectives: This case series aimed to assess the efficacy of a novel horizontal ridge augmentation modality using histology. Combinations of "sticky bone" and tenting screws without autologous bone were used as augmentative materials. Method and materials: Five individuals presenting healed, atrophic, partially edentulous sites that required horizontal bone augmentation before implant placement were enrolled. Patients underwent the same augmentation type and 5 months of postoperative reentry procedures. The first surgery served as implant site development, whereas the biopsy and corresponding implant placement were performed during reentry. The bone was qualitatively analyzed using histology and histomorphometry and quantitatively evaluated using CBCT. Results: Four individuals healed uneventfully. Early wound dehiscence occurred in one case. Histology showed favorable bone substitute incorporation into the newly formed bone and intimate contact between de novo bone and graft material in most cases. Histomorphometry revealed an average of 48 ± 28% newly formed bone, 19 ± 13% graft material, and 33 ± 26% soft tissue components. The CBCTbased mean alveolar ridge horizontal increase was 3.9 ± 0.6 mm at 5 months postoperatively. Conclusions: The described augmentation method appears suitable for implant site development resulting in favorable bone quality according to histology. However, clinicians must accommodate 1 to 2 mm of resorption in augmentative material width at the buccal aspect. [ABSTRACT FROM AUTHOR]

Purpose: To retrospectively determine the cumulative survival rate (CSR) and marginal bone level change (ΔMBL) around novel hybrid design tissue-level (TL) dental implants that support multiple-screw-retained restorations. Materials and Methods: Implant CSRs were analyzed at the implant and patient level using Kaplan-Meier estimates. ΔMBL was measured by comparing the periapical loading and follow-up visit radiographs using an improved standardized digital methodology based on image gray levels. ΔMBL outcomes were subject to linear mixed regression to identify potential risk factors. Results: A total of 301 TL implants in 69 patients with an average age of 62.6 ± 11.7 years (range: 36 to 87 years) at the time of implant placement were considered for the analysis. All 301 implants were successfully restored and loaded. The 54-month CSRs at the implant and patient levels were 98.9% (95% CI: 96.7 to 99.6) and 95.3% (95% CI: 86.1 to 98.5), respectively. ΔMBL after a mean follow-up of 22 ± 10.7 months after loading was 0.00 ± 0.57 mm. None of the implant sites showed marginal bone loss exceeding 1.5 mm. Multivariate regression analysis revealed a significant association between ΔMBL and the loading protocol (P = .027) but not between ΔMBL and age or transgingival height. Conclusions: The high CSRs and stable peri-implant marginal bone levels support the use of recent TL implants, which have a hybrid design inherited from the bone-level implant-abutment connection, as a suitable treatment option for restoring partially or fully edentulous patients with a good mid-term prognosis. These results should be complemented by further prospective studies in a real-world multicenter private practice setup that represents the daily realities of implant treatment. [ABSTRACT FROM AUTHOR]

Objectives: The consecutive case series accesses the results and experiences of ridge augmentation using an umbrella screw tenting technique. Method and materials: In total, 279 patients were treated between 26 May 2015 and 16 June 2021, including horizontal and vertical ridge defects. Sex, age, smoking behavior, jaw, graft material, soft tissue thickness, extent of horizontal/vertical augmentation, resorption rate, and occurrence of early/late exposure were evaluated. Bone gain was determined by resorption at the screw head. Only cases without premature screw removal were evaluated metrically (n = 201). All other augmentations were evaluated according to whether implantation was possible with or without further augmentation (n = 27). A target performance index was calculated, which should enable evidence-based comparability of different augmentation methods in future. Results: In total, 54 wound dehiscences (39 early, 15 late exposures) occurred, which corresponds to 24.08% of the augmented sites; 42 umbrella screws were removed prematurely. In all cases an implantation was possible at the desired position afterwards. Cases with a vertical augmentation component showed a higher prevalence of exposure (early, P = .000; late, P = .024). The extent of the vertical augmentation was only relevant for early exposure (P = .048). Mean bone gain of 4.23 ± 1.69 mm horizontally and 4.11 ± 1.99 mm vertically could be achieved. Regression analysis showed that there was no limit in horizontal/vertical direction. Mean percentage target performance index was 75.90 ± 20.54 for vertical and 82.25 ± 16.67 for horizontal portions. Conclusion: The umbrella technique is an effective augmentation method, which can be applied to any defect morphology. [ABSTRACT FROM AUTHOR]

The purpose of this study was to quantify the buccal bone thickness, area, and perimeter following guided bone regeneration (GBR) using stabilizing periosteal sutures. The loss in hard tissue volume may impair proper implant placement. GBR has been used to regenerate the lost alveolar ridge prior to or at the same time as dental implant placement. The most important factor for GBR success is graft stability. The periosteal mattress suture (PMS) stabilizing technique is an alternative to pins and screws to stabilize bone grafting material and has the advantage of not requiring the removal of the fixing devices. CBCT scan was acquired before and 6 months after surgery from six patients who underwent GBR with the PMS stabilizing technique. Images were analyzed for buccal bone thickness, area, and perimeter. The mean change in buccal bone thickness was 3.42 ± 1.31 mm and proved statistically significant (P = .005). The mean change in bone crest area also proved statistically significant (P = .001). No significant difference was found in bone perimeter (P = .12). The PMS technique delivered optimal results without clinical complications. This study shows the potential of this technique as an alternative to pins or screws for graft stabilization in the esthetic zone. [ABSTRACT FROM AUTHOR]

Purpose: To examine the stresses caused by different All-on-4 surgical techniques—conventional, a combination of monocortical and bicortical, bicortical, and nasal floor elevation—on the implant and the surrounding bone using 3D finite element analysis (FEA). Materials and Methods: A 3D bone model of the atrophic maxilla was created based on CT imaging of the fully edentulous adult patient. All implants used in the models were 4 mm in diameter, and the length was 13 mm in the anterior and 15 mm in the posterior. Implants were applied to four different atrophic maxillary models with the All-on-4 technique: anterior and posterior monocortical implants in the first model, anterior monocortical and posterior bicortical in the second model, anterior and posterior bicortical in the third model, and anterior and posterior bicortical with nasal floor elevation in the fourth model. Eight linear analyses were performed by applying force from both vertical and 45-degree oblique directions to the four models prepared in our study. Results: When the cortical and cancellous bone around the anterior implants was examined, it was observed that the oblique and vertical loading conditions and the stresses around the implant were similar in all models. When the posterior implants were examined, model 1 (ie, anterior and posterior monocortical implants) showed the greatest oblique compression, vertical compression, and vertical tension forces. According to the Von Mises stress (VMS) analysis results for anterior and posterior implants, higher values were observed in model 1 compared to models 3 and 4 under oblique and vertical forces. It was observed that bicortical placement of the implants reduced the stresses on the bone and implant-abutment system but had no significant effect on the stress on the bar. Conclusions: According to the results of our study, in the All-on-4 technique, bicortical placement of the implants reduced the stresses on the bone and implant when the anatomical limitations allowed. In addition, nasal floor elevation can be applied in the atrophic maxilla in appropriate indications. [ABSTRACT FROM AUTHOR]

Background: Calcaneal fractures are the most common type of tarsal fractures. The sustentaculum tali (ST) offers anatomical stability in calcaneal fractures, and recently, ST screws have been widely used in their treatment. This study aimed to investigate the clinical efficacy and value of ST screw fixation via a modified sinus tarsi approach (MSTA) for treating displaced intraarticular calcaneal fractures (DIACFs). Methods: This study enrolled 64 patients (64 feet): 32 patients in the calcaneal locking plate combined with the ST screw group (CLP-STS Group) and 32 patients in the simple calcaneal locking plate internal fixation group (CLP Group). The minimum follow-up duration was 18 months. Ankle function was evaluated using VAS, AOFAS, and Short Form-36 scores. Imaging evaluation included the Böhler angle, Gissane angle, length, height, and width of the calcaneus, and the Böhler angle in both groups 1 year after surgery. Results: Functional evaluation revealed that postoperative AOFAS and VAS scores in the CLP-STS Group were significantly better than those in the CLP Group. After surgery, the Böhler angle, Gissane angle, and length, height, and width of the calcaneus were significantly corrected compared to the preoperative values; however, the difference in these indicators between the two groups was not significant. Nevertheless, at the 1-year postoperative follow-up, the calcaneal Böhler angle loss in the CLP-STS Group was significantly better than that in the CLP Group. Conclusion: Compared to simple calcaneal locking plate internal fixation, combining the plate with the additionally free ST screw can resolve the limited intraoperative exposure of MSTA, reduce postoperative foot pain in patients, and improve clinical efficacy. [ABSTRACT FROM AUTHOR]

Background: Orthopedic surgeries often involve the insertion of bone screws for various fixation systems. The risk of postoperative screw loosening is usually assessed through experimental or finite element (FE) evaluations of the screw pull-out strength. FE simulations are based on either personalized complex but accurate heterogeneous modeling or non-personalized simple but relatively less accurate homogeneous modeling. This study aimed to develop and validate a novel personalized computed tomography (CT)-based homogeneous FE simulation approach to predict the pull-out force of cancellous bone screws. Methods: Twenty FE simulations of L1-L5 vertebral screw pull-out tests were conducted, i.e., 10 heterogeneous and 10 homogenous models. Screws were inserted into the lower-middle region of vertebrae. In our novel homogeneous model, the region around approximately twice the diameter of the screw was used as a bone material reference volume. Subsequently, the overall material property of this region was homogeneously attributed to the entire vertebra, and pull-out simulations were conducted. Results: The mean error of the predicted pull-out forces by our novel homogenous simulations was ~ 7.9% with respect to our heterogeneous model. When solely the cancellous bone was involved during the pull-out process (i.e., for L1, L2, and L3 vertebral bodies whose cortical bone in the inferior region is thin), the novel homogenous model yielded small mean error of < 6.0%. This error, however, increased to ~ 11% when the screw got involved to the cortical bone (for L4 and L5 vertebrae whose cortical bone in the inferior region is thick). Conclusion: The proposed personalized CT-based homogenous model was highly accurate in estimating the pull-out force especially when only the cancellous bone was involved with the screw. [ABSTRACT FROM AUTHOR]

Background: The purpose of this study is to explore the feasibility and accuracy of a robot-assisted technique in four-corner fusion compared with traditional freehand operation. Methods: Twenty cadaver specimens were randomly assigned to the robot-assisted group and freehand groups. Three screws were placed percutaneously to fix the capitate-lunate joint, lunate-triquetrum joint, and triquetrum-hamate-capitate joint in each specimen by robot-assisted or freehand technique. The offset between the actual and planned screw positions was determined by merging the images of intraoperative and postoperative CT scans in the robot-assisted group. The centrality of the screw, time-consuming, drilling attempts, and radiation exposure were compared between the two groups. Results: The mean offset between the actual and planned screw position was 1.09 (SD: 0.56) mm. The offset at the start point of the screw was significantly lower than that at the endpoint. There was no significant difference in the centrality of the screws, surgical time between the two groups. The number of drilling attempts and the radiation dose received by surgeons were significantly lower in the robot-assisted group. Conclusions: Although there was no significant difference in screw centrality between the two groups, the slight offset between the actual and planned screw positions confirmed the feasibility of the robot-assisted technique in four-corner fusion. The robot-assisted technique has advantages in reducing the difficulty of surgery and protecting the surgeon from exposure to large doses of radiation. [ABSTRACT FROM AUTHOR]

Background: While the benefits of sonication for improving periprosthetic joint infection (PJI) are well-documented, its potential therapeutic effect against bacterial biofilm remains unstudied. This study aimed to investigate the safety and efficacy of a novel nanoparticle ultrasonication process on methicillin-resistant Staphylococcus aureus (MRSA) bacterial biofilm formation in a PJI rat model. Methods: This novel ultrasonication process was designed to remove attached bacterial biofilm from implant and peri-articular tissues, without damaging native tissues or compromising implant integrity. Twenty-five adult Sprague–Dawley rats underwent a surgical procedure and were colonized with intra-articular MRSA, followed by the insertion of a titanium screw. Three weeks after the index surgery, the animals received a second procedure during which the screws were explanted, and soft tissue was sampled. The intraoperative use of the nanoparticle sonication treatment was employed to assess the device's safety, while ex vivo treatment on the retrieved tissue and implants was used to evaluate its efficacy. Results: Clinical and histological assessments did not indicate any macro- or micro-damage to the host tissue. Sonication of the retrieved tissues demonstrated an average bacterial removal of 2 × 103 CFU/mL and 1 × 104 CFU/gram of tissue. Compared to the standard-of-care group (n = 10), implants treated with sonication (n = 15) had significantly lower remaining bacteria, as indicated by crystal violet absorbance measurements (P = 0.012). Conclusions: This study suggests that nanoparticle sonication technology can successfully remove attached bacterial biofilms from explanted orthopedic hardware and the joint capsule, without negatively affecting native tissue. The study provides initial results supporting the potential of nanoparticle sonication as an adjuvant treatment option during a DAIR (debridement, antibiotics, and implant retention) procedure for PJI, paving the way for future clinical trials. [ABSTRACT FROM AUTHOR]

Objective: The cortical bone trajectory (CBT) technology is an effective substitute for traditional pedicle screw (PS) technology. However, there is still controversy about the CBT screw technology placement strategy. The objective of this study was to simulate cortical screw placement with the help of three‐dimensional (3D) software, to discuss the differences in screws between genders and vertebral segments, and to explore a safer and more efficient strategy for cortical screw placement. Methods: Mimics Medical software was used to construct a 3D model of the lumbar spine, and the placement of CBT screws was simulated. The volume of each vertebral body from L1 to L5, the pedicle isthmus height (IH), the pedicle isthmus width (IW), and the sagittal vertebral distance (SAVD) were measured. The transverse distance (TD) and the longitudinal distance (LD) between the ideal starting point (SP) and the clinical SP (the intersection Q of the midline of the superior articular process and the horizontal line 1 mm below the transverse process) were measured. The cephalad angle (CA), lateral angle (LA), maximum screw diameter (MSD), maximum screw length (MSL) of each trajectory of the L1 to L5 vertebral bodies, and the percentage of the screw insertion depth (PSID) into the vertebral body were measured. Data were statistically analyzed using Student's t‐test, one‐way analysis of variance (ANOVA), and Tukey's test. Results: Vertebral anatomical parameters and CBT screw parameters differed between males and females. Female patients had lower IH, IW, SAVD, CA, LA, MSD, and MSL than males. IH was greatest in L1 (male, 17.81 mm; female, 16.12 mm) and the smallest in L5 (male, 14.11 mm; female, 13.05 mm). IW was smallest in L1 (male, 8.89 mm; female, 7.37 mm) and greatest in L5 (male, 16.59 mm; female, 15.43 mm). The MSD of males was smallest in L1 (6.05 mm) and greatest in L3 (7.06 mm); the MSD of females was smallest in L1 (5.13 mm) and greatest in L4 (6.64 mm). MSL was greatest at L3 (male, 33.63 mm; female, 32.28 mm) and smallest at L5 (male, 31.25 mm; female, 29.97 mm). CA was smallest in L1 (male, 22.80°; female, 21.92°) and greatest in L3 (male, 25.29°; female, 24.33°). LA was smallest in L1 (male 12.37°, female 11.27°) and greatest in L5 (male 13.56°, female 12.96°). Among the males, TD was smallest at L1 (−0.51 mm) and greatest at L5 (1.37 mm), while LD was greatest at L2 (3.46 mm) and smallest at L5 (2.40 mm). In females, TD was greatest at L1 (0.12 mm) and smallest at L3 (−0.51 mm), while LD was greatest at L1 (3.69 mm) and smallest at L5 (2.08 mm). In the overall sample, the incidence of SAVD and PSID gradually increased from L1 to L5. Conclusion: The optimal screw placement strategy for CBT screws varies significantly according to sex and vertebral body segments, particularly noting the specificity of screw placement at L5. The optimal screw placement strategy should be selected based on the patient's sex and segment characteristics before surgery to maximize the safety and accuracy of CBT screw placement. [ABSTRACT FROM AUTHOR]

Objectives: Although numerous surgical techniques and fixation methods have been described for the treatment of hallux rigidus (HR) with arthrodesis, consensus on the gold standard treatment has not been reached. The aim of this study is to retrospectively compare the clinical and radiological outcomes of compression screw fixation and plate fixation in the treatment of HR with arthrodesis. Methods: Patients who underwent arthrodesis surgery due to HR between January 2021 and December 2023 at a single center were retrospectively reviewed. Patients who met the inclusion criteria were divided into two groups: those who underwent arthrodesis with plate fixation (PLATE) and those who underwent arthrodesis with compression screw fixation (SCREW). Demographic data including age, gender, affected side, operative time, hallux valgus angle (HVA), dorsiflexion angle, AOFAS scores, and implant irritation data were compared among patients with at least 3 months of follow-up. Results: It was observed that all patients included in the study had successful bone union without any complications. There were no significant differences between the two groups in terms of age, gender, affected side, preoperative HVA, and preoperative AOFAS scores (P= 0.970, P= 0.426, P= 0.694, P= 0.216, and P= 0.905, respectively). The mean operation time and postoperative AOFAS score were lower in the PLATE group compared to the SCREW group (P=0.006 and P=0.004, respectively). However, in the SCREW group, the dorsiflexion angle and the rate of implant irritation were lower compared to the PLATE group (P=0.016 and P=0.01, respectively). Conclusions: In the surgical treatment of HR, both plate fixation arthrodesis and compression screw arthrodesis are reliable surgical techniques. While plate fixation arthrodesis is a faster and more practical method, arthrodesis with a compression screw results in fewer complaints related to the implant and provides a more functional recovery. [ABSTRACT FROM AUTHOR]

In orthopedic surgery, precise bone screw insertion is crucial for stabilizing fractures, necessitating a preliminary cortical bone drilling procedure. However, this process can induce temperatures exceeding 70 °C due to the low thermal conductivity of cortical bone, potentially leading to thermal osteonecrosis. Furthermore, significant cutting forces and torque pose risks of tool breakage and bone damage, underlining the need for high precision and optimal processing parameters. Traditionally, drilling relies on the surgeon's experience and often results in imprecise outcomes due to inconsistent feed rates. Therefore, this study proposes the use of a 6-axis robot for controlled drilling, offering precise control over angular velocities and consistent feed rates. Additionally, explore the use of cryogenic liquid nitrogen (LN2) as a novel cooling method compared to conventional saline solutions, examining its efficacy under various cutting conditions. The results demonstrate that LN2 cooling conditions lead to a reduction in thrust and torque under specific processing conditions, and facilitate smoother chip evacuation. Additionally, LN2 significantly lowers the peak temperature around the drilling site, thus minimizing the risk of thermal osteonecrosis. Consequently, the use of a 6-axis robot provides consistent feed rates, and LN2 cooling achieves optimal processing conditions, enabling a more controlled and effective drilling process. [ABSTRACT FROM AUTHOR]

Study Design: Retrospective comparative study. Objective: To compare the accuracy of intra-operative navigation-assisted percutaneous pedicle screw insertion between bone fixed and skin fixed dynamic reference frame (DRF) in Minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF). Methods: Between October 2018 and September 2022, patients who underwent MIS-TLIF were included in this study with DRF fixed either on bone (group B) or skin (group S). Pedicle screws were inserted under the guidance of intra-operative Cone bean Computed tomography (cbCT) based navigation. Accuracy of pedicle screw placement was immediately checked by a final intra-operative cbCT Spin. Results: Among 170 patients, group B included 91 patients and group S included 79 patients. Out of total 680 screws, 364 screws (group B) and 316 screws (group S) were placed. Patient's demographic data and distribution of screws showed no statistically significant difference. The accuracy showed no significant difference between both the groups (94.5% in group B and 94.3% in group S). Conclusion: Skin fixed DRF can serve as an alternate way for placement and avoids extra incision with similar accuracy in pedicle screw insertions with bone fixed DRF using intra-operative CT guided navigation in MIS TLIF. [ABSTRACT FROM AUTHOR]

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Background: This study aimed to investigate the impact of three-dimensional (3D)-printed guide plate-assisted percutaneous pedicle screw implantation on minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) surgery. Methods: Overall, 162 patients who underwent MIS-TLIF at Tai'an City Central Hospital were retrospectively reviewed. The studied variables included operative time, volume of intraoperative blood loss, fluoroscopy time, postoperative drainage volume, visual analogue scale (VAS) score, Oswestry disability Index (ODI) score (preoperatively and at 2 weeks, 3 months, 6 months, and 12 months after surgery), and intervertebral fusion rate at 6 months after surgery. Results: The conventional group included 99 patients who underwent a conventional procedure, while the 3D printing group included 63 patients who underwent 3D-printed guide plate-assisted percutaneous pedicle screw implantation. The conventional group required more times of positioning needle punctures than the 3D printing group (22.2 ± 5.9 vs. 16.1 ± 4.9). The operation and fluoroscopy time were also longer in the former group (183.5 ± 51.1 min vs. 148.8 ± 40.3 min and 30.2 ± 5.9 s vs. 24.1 ± 4.9 s, respectively). In 3D printing group, lower back pain VAS scores and ODI scores at 2 weeks and 3 months after surgery were observed. There were no significant differences in terms of the volumes of intraoperative blood loss; postoperative lower limb pain VAS scores; and interbody fusion rate (P > 0.05). Conclusion: The novel 3D-printed guide plate-assisted percutaneous pedicle screw implantation can achieve better amelioration of back pain and recovery of function. It also reduced the times of positioning needle puncture and fluoroscopy time during percutaneous screw placement surgery and reduced the duration of surgery. [ABSTRACT FROM AUTHOR]

Background: To evaluate the feasibility and safety of the superficial circumflex iliac perforator flap (SCIP) for maxillary reconstruction with intraoral anastomosis, pedicle elongation, and super-microsurgery techniques to overcome its anatomical shortcomings due to the attractive merits of the flap. Methods: Patients who underwent reconstruction of maxillary defects with SCIPs from July 2020 to December 2022 were included. Intraoral anastomosis, pedicle elongation, and super-microsurgery were performed during surgery with or without a neck incision. The sizes, pedicle lengths, inner calibres of vessels, complications and flap survival statuses were recorded. Results: A total of 12 patients were included, with 3 males and 9 females, and the median age was 45 years, ranging from 14 to 74 years. There were 5 class IIa and 7 class IIb defects, 6 cases underwent maxillary defect reconstruction via SCIPs with intraoral anastomosis, and the other 6 cases with distally design and/or de-epidermis pedicle elongation. Super-microsurgery interventions were needed in 5 patients. The size ranged from 3 cm×4 cm to 6 cm×8 cm. The pedicle length ranged from 4 cm to 12 cm, with a median of 6 cm. The inner caliber of the arteries ranged from 0.7 mm to 2 mm, with a median of 1 mm, and the veins ranged from 1.5 mm to 4 mm, with a median of 2.5 mm. All the flaps survived, and no donor site complications occurred. Conclusion: Superficial circumflex iliac perforator flaps can be regarded as feasible and safe choices for maxillary defects with the support of intraoral anastomosis, pedicle elongation and super-microsurgery. [ABSTRACT FROM AUTHOR]

Purpose: The goal of this retrospective study was to perform a CT imaging assessment of thoracic pedicles to provide a representative understanding of pedicle morphology for pedicle-based fixation systems commonly used in orthopedics, trauma and neurosurgery. This study aimed to better understand the morphology of the spine and give spine surgeons a better understanding of thoracic spine anatomy. Methods: In this study, we retrospectively measured the thoracic spine pedicles of a total of 16 males and 16 females, totaling in 768 individual pedicles. For the measurements, we used standardized planes in computed tomography imaging with a maximum slice thickness of 1 mm. Results: In brief, we identified significant differences in various measurements of male and female pedicle morphology. The medial cortical wall of the pedicles was significantly thicker than the lateral wall, and, in both sexes, the thoracic vertebral body number four was the vertebra with the least amount of cortical bone in the pedicle. Conclusions: Surgeons performing operations involving pedicle screw placement should be aware of the sex-specific differences in thoracic spine pedicle morphology noted in this research. [ABSTRACT FROM AUTHOR]

Background: Traditional fixation methods for posterior wall acetabular fractures (PWAFs) typically require the utilization of multiple plates and intraoperative plate contouring, which are technically demanding and carry the risk of intra-articular screw penetration. A novel posterior anatomical integrated locking compression plate (PAILCP) has been designed to optimize these shortcomings. This study aims to evaluate the feasibility and effectiveness of the PAILCP fixation method for the surgical management of PWAFs. Methods: A total of 48 patients with PWAFs who were treated surgically in our department between January 2018 and December 2022 were selected for retrospective analysis. The 48 patients were classified into groups A (PAILCP fixation, n = 25) and B (traditional fixation, n = 23) according to different fixation methods. Fracture reduction quality, number of utilized plates, blood loss, surgical time, instrumentation time, hip function, and complications were compared between the two groups. Results: A total of 25 PAILCPs were used in group A, while 34 mini-T plates and 29 reconstruction plates were employed in group B. Compared to the patients in group B, those in group A had significantly shorter instrumentation time (− 16 min) and surgical time (− 23 min) as well as lower blood loss (− 123 ml). However, no significant differences were observed in fracture reduction quality and hip function between the two groups. Additionally, the complication rate was slightly lower in group A (3/25 patients) than in group B (6/23); however, this difference was not statistically significant. Finally, follow-up examination revealed no main plate breakage, miniplate displacement, screw loosening, or intra-articular screw penetration in all patients. Conclusion: The surgical treatment of PWAFs using the PAILCP fixation method results in shorter instrumentation and surgical time and lower blood loss than the traditional fixation method. Thus, the PAILCP fixation method is a promising alternative for PWAFs management, offering enhanced surgical ease and safety. [ABSTRACT FROM AUTHOR]

Purpose: We aim to compare interfragmentary compression with the position osteosynthesis in the fixation of different femoral neck fractures (FN) in synthetic bones subjected to vertical load. Methods: Forty-two synthetic femurs were subjected to neck fractures and separated into 3 groups according to the Pauwels classification: Pauwels I had 6 units (PI); Pauwels II, 24 units, with and without comminution (PII); and Pauwels III, 12 units, with and without comminution (PIII). After, they were fixed with 2 different ways: three 7, 0 mm cannulated lag screws (CSs) versus three 6, 5 mm solid fully threaded screws (SSs). Screws positioning was oriented by the Pauwels classification: inverted triangle or crossed screws. All specimens were submitted to vertical loading until failure. Results: The average force was 79.4 ± 22.6 Kgf. The greatest one was recorded in model 1 (135.6 Kgf), and the lowest in model 41 (39.6 Kgf). CSs and SSs had similar resistance until failure (p = 0.2). PI showed heightened resistance and PIII showed a worse response (p < 0,01). CSs had better performance in PIII (p = 0.048). Comminution and screws orientation caused no difference on peak force (p = 0.918 and p = 0.340, respectively). Conclusions: In synthetic bones, the resistance of a femoral neck fracture osteosynthesis using a 7, 0 mm cannulated lag screw or 6, 5 mm solid fully threaded screw are similar. There was no loss of efficiency with comminution in the femoral neck. Osteosynthesis resistance decreased with the verticalization of the fracture line and, in the more vertical ones, interfragmentary compression with CSs was more resistant than positional osteosynthesis with SSs. [ABSTRACT FROM AUTHOR]

Background: In recent years, the medical community has witnessed a notable increase in high-energy traumatic injuries, leading to a surge in complex fracture patterns that challenge existing treatment methodologies. Among these, the posterior approach to acetabular fractures stands out for offering direct visualization of the retro-acetabular surface, with current fixation methods relying on 3.5 mm low-profile reconstruction plates and various other implants. Despite the effectiveness of these methods, there is a burgeoning demand for a singular, adaptable implant that not only streamlines the surgical process but also optimizes patient outcomes. Methods: In an innovative approach to address this need, three-dimensional (3D) models of the posterior acetabular wall were meticulously crafted using AutoCAD® software. The chosen material for the implant was 316L surgical steel for its durability and strength. The design of the implant featured a low-profile mesh structure, which was instrumental in facilitating osteosynthesis. This design allowed for the placement of screws of varying lengths in multiple directions, ensuring the initial reconstruction of the joint in an anatomical position without hindering the placement of the definitive implant. The primary objective was to secure the fixation and stabilization of the fracture by specifically targeting the smaller bone fragments. A comparative analysis was then conducted between this novel plate and a conventional 316L surgical steel, seven-hole, 3.5 mm reconstruction plate through finite element analysis. Results: The comparative analysis unveiled that both plates demonstrated comparable deformation capacities, with no significant differences in load-bearing capabilities observed. This finding suggests that the innovative plate can match the performance of traditional plates used in such surgeries. Conclusions: The finite element analysis revealed that the newly developed anatomical plate for posterior wall acetabular fractures meets the necessary physical and mechanical criteria for permanent implementation in patients with these fractures. This breakthrough represents a promising advancement that could simplify surgical procedures and potentially elevate patient outcomes. Level of Evidence II: This study is classified as a Level II, diagnostic study. [ABSTRACT FROM AUTHOR]

Purpose: To review surgical complications after fixation of stress-positive minimally displaced (< 1 cm) lateral compression type 1 (LC1) pelvic ring injuries. Methods: A retrospective study at a level one trauma center identified patients who received surgical fixation of isolated LC1 pelvic ring injuries. Surgical complications and additional procedures were reviewed. Results: Sixty patients were included. The median age was 61 years (Interquartile range 40–70), 65% (n = 39) were women, and 57% (n = 34) had high-energy mechanisms. Anterior–posterior, posterior-only, and anterior-only fixation constructs were used in 77% (n = 46), 15% (n = 9), and 8% (n = 5) of patients. Anterior fixation was performed with rami screw fixation in 82% (49/60), external fixation in 2% (1/60), and open reduction and plate fixation in 2% (1/60). There were 15 surgical complications in 23% (14/60), and 12 additional procedures in 17% (10/60). Complications included loss of reduction ≥ 1 cm (8%), symptomatic hematomas (8%), symptomatic backout of unicortical retrograde rami screws (5%), deep infection of the pelvic space after a retrograde rami screw (1.6%), and iatrogenic L5 nerve injury (1.6%). All losses of reduction involved geriatric females with distal rami fractures sustained in ground-level falls. Loss of reduction was found to be more likely in patients with low energy mechanisms (proportional difference (PD) 62%, 95% confidence interval (CI) 18% to 76%; p = 0.01) and 2 versus 1 posterior pelvic screws (PD 36%; CI 0.4% to 75%; p = 0.03). Conclusions: Surgical complications and additional procedures routinely occurred after fixation of LC1 injuries. Patients should be appropriately counseled on the risks of surgical fixation of these controversial injuries. Level of Evidence: Diagnostic, Level III. [ABSTRACT FROM AUTHOR]

Purpose: To determine union and displacement metrics following percutaneous screw fixation (antegrade or retrograde) of superior pubic rami fractures. Methods: This is a retrospective cohort study from a single level 1 trauma center. Skeletally mature patients with at least one superior pubic ramus fracture present as part of a lateral compression-type pelvic ring injury were included. Results: Eighty-five (85) patients with 95 superior pubic rami fractures met the study's inclusion criteria. LC1, LC2, and LC3 injuries occurred in 76.5%, 15.3%, and 8.2% of patients, respectively. The majority of patients underwent concurrent posterior pelvic ring fixation (94.1%). Superior ramus screw placement occurred predominantly via retrograde technique (81.1%) with cannulated screws of size 6.5 mm or larger (93.7%). Of the 95 eligible fractures, 90 (94.7%) achieved union at a mean of 14.0 weeks (7–40 weeks). Of these united fractures, 69 (76.7%) healed with no measurable displacement, while the remaining 23.3% healed with residual mean displacement of 3.9 mm (range: 0.5–9.0 mm). Multivariable analysis demonstrated a positive association between age (p = 0.04) and initial displacement (p = 0.04) on the final degree of residual displacement at union. A Kaplan–Meier survival analysis identified increased age to be significantly related to increased time to union (X2 (2) = 21.034, p < 0.001). Conclusions: Union rates following percutaneous screw fixation of superior pubic rami fractures associated with lateral compression-type pelvic ring injuries approach 95%. Though minimal in an absolute sense, increasing age and a greater degree of initial displacement may influence the final degree of residual displacement at union. Level of evidence: IV. [ABSTRACT FROM AUTHOR]

Purpose: To describe U-type sacral fracture characteristics amenable to percutaneous sacral screw fixation. Methods: U-type sacral fractures were identified from a trauma registry at a level 1 trauma center from 2014 to 2020. Patient demographics, injury mechanism, fracture characteristics, and fixation construct were retrospectively retrieved. Associations between fracture pattern and surgical fixation were identified. Results: 82 U-type sacral fractures were reviewed. Six treated with lumbopelvic fixation (LPF) and 76 were treated with percutaneous sacral screws (PSS) alone. Patients receiving LBF had greater sacral fracture displacement in coronal, sagittal, and axial planes compared to patients receiving PSS alone (P < 0.05), negating osseous fixation pathways. All patients went onto sacral union and there were no implant failures or unplanned reoperations for either group. Conclusion: If osseous fixation pathways are present, U-type sacral fractures can be successfully treated with percutaneous sacral screws. LPF may be indicated in more displaced fractures with loss of spinopelvic alignment. Both techniques for U-type sacral fractures result in reliable fixation and healing without reoperations. [ABSTRACT FROM AUTHOR]

Screw loosening is a common complication of pedicle screw internal fixation surgery. This study aimed to investigate whether the application of a porous scaffold structure can increase the contact area between screws and bone tissue by comparing the bone ingrowth and screw-bone interface of porous scaffold core pedicle screws (PSCPSs) and hollow lateral hole pedicle screws (HLHPSs) in the lumbar spine of Bama pigs. Sixteen pedicle screws of both types were implanted into the bilateral pedicles of the L1–4 vertebrae of 2 Bama pigs. All Bama pigs were sacrificed and the lumbar spine was freed into individual vertebrae at 16 weeks postoperatively. After the vertebrae were made into screw-centered specimens, micro-computed tomography analysis and histological observation were performed to assess the screw-bone interface and bone growth around and within the screws. We found that the bone condition around PSCPSs and HLHPSs did not show significant differences on micro-computed tomography three-dimensional reconstruction images. CT transverse views showed different bone growth inside the 2 screws. In PSCPSs, bone tissue was seen to fill the internal pores and was evenly distributed around each strut. Inside HLHPSs, bone growth was confined to 1 side of the screw and did not fill the entire cavity. Osteometric analysis showed that bone volume fraction and trabecular number, the parameters representing bone mass, were higher in PSCPSs than in HLHPSs. These differences were not statistically significant (P > 0.05). Histological observations visualized that the osseointegration within PSCPSs was superior to that of HLHPSs, and the tight integration of bone tissue with the porous scaffold resulted in a larger screw-bone integration area in PSCPSs than in HLHPSs. Compared with HLHPSs, PSCPSs possessing a porous scaffold core could promote bone ingrowth and osseointegration, resulting in an effective enhancement of the combined area of the screw-bone interface. [ABSTRACT FROM AUTHOR]

Objectives: To assess navigation accuracy for complete‐arch implant placement with immediate loading of digitally prefabricated provisional. Materials and Methods: Consecutive edentulous and terminal dentition patients requiring at least one complete‐arch FDP were treated between December 2020 and January 2022. Accuracy was evaluated by superimposing pre‐operative and post‐operative cone beam computed tomography (CBCT), recording linear (mm) and angular (degrees) deviations. T‐tests were performed to investigate the potential effect of the registration algorithm (fiducial‐based vs. fiducial‐free), type of references for the fiducial‐free algorithm (teeth vs. bone screws), site characteristic (healed vs. post‐extractive), implant angulation (axial vs. tilted), type of arch (maxilla vs. mandible) on the accuracy with p‐value <0.05. Results: Twenty‐five patients, 36 complete‐arches, and 161 implants were placed. The overall mean angular deviation was 2.19° (SD 1.26°). The global platform and apex mean deviations were 1.17 mm (SD 0.57 mm), and 1.30 mm (SD 0.62 mm). Meaningful global platform (p = 0.0009) and apical (p = 0.0109) deviations were experienced only between healed and post‐extraction sites. None of the analyzed variables significantly influenced angular deviation. Minor single‐axis deviations were reported for the type of jaw (y‐axis at implant platform and apex), registration algorithm (y‐axis platform and z‐axis deviations), and type of references for the fiducial‐free algorithm. No statistically significant differences were found in relation to implant angulation. Conclusions: Within the study limitations navigation was reliable for complete‐arch implant placement with immediate loading digitally pre‐fabricated FDP. AI‐driven surface anatomy identification and calibration protocol made fiducial‐free registration as accurate as fiducial‐based, teeth and bone screws equal as references. Implant site characteristics were the only statistically significant variable with healed sites reporting higher accuracy compared to post‐extractive. Live‐tracked navigation surgery enhanced operator performance and accuracy regardless of implant angulation and type of jaw. A mean safety room of about 1 mm and 2° should be considered. [ABSTRACT FROM AUTHOR]

Objective: Dental implants placed in adolescent patients pose a challenge to restore and maintain an esthetic outcome over longer period of follow‐up. Maxillomandibular changes throughout adulthood may lead to complications such as implant infraocclusion and interproximal contact loss. This case report describes an alternate prosthetic treatment strategy for maxillary single implant placed in an adolescent patient in the esthetic zone with inappropriate implant axis and screw hole placement. Clinical considerations: With temporary restorations, the gingiva and soft tissues were shaped to imitate the emerging profile of the contralateral side. A zirconia screw‐retained abutment was customized as a copy‐mirror from the contralateral prepared tooth to mimic the exact shape and to avoid labiolingual over contour by computer‐aided design/computer‐assisted manufacture (CAD/CAM). The porcelain laminate veneer was bonded to the zirconia abutment. Porcelain adhesive approach was used instead of traditional principles of retention and resistance form of the abutment. Conclusions: A functional and esthetic outcome was achieved and maintained, while a minimally invasive procedure was implemented to use the malplaced implant instead of explanting it. Clinical significance: The present report illustrates the prosthetic management of a malpositioned dental implant placed 20 years ago, utilizing a minimally invasive digital protocol. [ABSTRACT FROM AUTHOR]

Summary: Pedicle screw loosening after posterior lumbar fusion is associated with poor bone quality, which often determines screw pull‐out strength, insertion torque, and vertebral body loading characteristics. Magnetic resonance imaging (MRI)‐based vertebral bone quality (VBQ) score were associated with poor bone quality. Current evidence suggests that pedicle bone quality (PBQ) has a greater impact on screw stability. However, the correlation between MRI‐based PBQ score and screw loosening has not been reported. Purpose: To introduce and evaluate an MRI‐based PBQ score to determine its effectiveness in predicting pedicle screw loosening following lumbar fusion surgery. Methods: The retrospective study analyzed 244 patients who underwent posterior lumbar interbody fusion (PLIF) with pedicle screws between December 2017 and December 2021, with CT and MRI imaging before surgery. Data collected included patient demographics and preoperative radiological data. Radiographic screw loosening was measured at 12 months postoperatively. Clinical assessments included pain visual analog scale (VAS) and Oswestry Disability Index (ODI) scores. The PBQ score was measured using MRI scans. We use univariate analysis for preliminary screening of the risk factors of screw loosening. Subsequent analysis involved multivariate logistic regression to identify independent predictive factors for screw loosening. We constructed the receiver operating characteristic (ROC) curve to ascertain the discriminative capacity of the PBQ score. The area under the curve (AUC) quantified its predictive accuracy. Additionally, we evaluated the association between PBQ score and screw loosening using Spearman's correlation analysis. Results: Overall, 244 patients who underwent PLIF with pedicle screw fixation participated in this study, including 35 in the loosening group and 209 in the non‐loosening group. PBQ score in the loosening group was significantly higher than that in the non‐loosening group. On multivariate logistic regression, the higher PBQ score (OR = 8.481, 95% CI: 3.158–22.774; p < 0.001) and the lower mean Hounsfield unit (HU) value of L1‐4 (OR = 0.967, 95% CI 0.951–0.984; p < 0.001) were the variables that significantly predicted screw loosening. The AUC for the PBQ score and HU value were 0.751 (95% CI: 0.673–0.828) and 0.702 (95% CI: 0.612–0.791). The PBQ score optimal cutoff to differentiate patients with loosening and with non‐loosening was calculated as 3.045 with a sensitivity of 85.7% and specificity of 76.9%, while the optimal cutoff of the HU value was 151.5 with a sensitivity of 64.6% and specificity of 89.5%. Conclusions: The association between the PBQ score and the propensity for lumbar pedicle screw loosening was found to be substantial. As a predictive measure, the PBQ score outperformed the HU value in forecasting the likelihood of screw loosening post‐posterior lumbar fusion. [ABSTRACT FROM AUTHOR]

A corrosion study is performed on six variations of titanium grade 5 (Ti6Al4V) samples. Samples are prepared in different conditions by variation of preanodization, postanodization, and picosecond‐laser (ps‐laser) surface treatment, while polished and anodized samples serve as reference. Microcones and nanosized periodic surface features are successfully produced on Ti6Al4V samples. The morphology and topography of the structures are visualized by scanning electron microscopy and white light interference microscopy. Furthermore, the relative electrochemically active surface area (ECSA) is determined for the ps‐laser‐treated samples. It is determined that the preanodized and laser‐treated sample has 3.5 times larger ECSA than a polished sample, and that the laser‐treated sample has 4.1 times larger area. Moreover, Tafel analysis is performed to determine the corrosion properties of the samples. It is shown that the corrosion resistance improves for both laser‐structured samples after the anodization. To further study the surface of the samples, electrochemical impedance spectroscopy measurements are conducted. The study indicates that the ps‐laser‐treated and anodized Ti6Al4V is suitable to be used for the fabrication of bone screws and plates due to its improved corrosion resistance as compared to nonanodized samples. [ABSTRACT FROM AUTHOR]

OBJECTIVE The objective of this study was to determine the effects of repeated steam sterilization cycles on the biomechanical properties of surgical screws. METHODS 42 3.5-mm and 42 2.0-mm self-tapping, cortical screws were divided into 3 groups per size and underwent autoclave sterilization for 1 (G1), 50 (G50), or 100 (G100) cycles and testing from August 2018 through June 2021. Sixty screws were then inserted into canine cadaver femurs, and biomechanical properties were measured, including peak insertional torque, torque to failure, and pullout strength, each normalized to cortical thickness. Scanning electron micrographs were taken from 24 screws, and images were blindly analyzed by 5 trained examiners. RESULTS The mean normalized insertion torque for 3.5-mm screws was significantly different between G1 and both G50 and G100. The mean normalized torque to failure for 3.5-mm screws was significantly different between G1 and both G50 and G100. Axial pullout testing was found to be significantly different for 2.0-mm screws between G1 and G100. Scanning electron micrographs surface scoring identified a significant difference in 3.5-mm screws at the screw tip. CONCLUSIONS The results indicate that biomechanical changes occur with repeated steam sterilizations. Specifically, peak insertional torque and torque to failure are decreased with increased sterilizations for 3.5-mm screws, whereas 2.0-mm screws were altered in pullout testing after 100 sterilizations. It is suspected that numerous sterilizations negatively alter the physical-mechanical properties of certain screw sizes. CLINICAL RELEVANCE The biomechanical properties of the bone-implant interface could negatively be affected by multiple steam sterilizations during clinical setting. [ABSTRACT FROM AUTHOR]

Thread shape is regarded as an important factor influencing the fixation strength and osseointegration of bone screws. However, commercial pedicle screws with a V-shaped thread are prone to generating stress concentration at the bone-screw interface, thereby increasing the risk of screw loosening. Thus, modification of the pedicle-screw thread is imperative. This study aimed to investigate the fixation stability of pedicle screws with the new undercut thread design in comparison to pedicle screws with a V-shaped thread. In vitro cadaveric biomechanical test and finite element analysis (FEA). Pedicle screws with the undercut thread (characterized by a flat crest feature and a tip-facing undercut feature) were custom-manufactured, whereas those with the V-shaped thread were procured from a commercial supplier. Fixation stability was assessed by the cyclic nonpullout compressive biomechanical testing on cadaveric female osteoporotic vertebrae. The vertical displacement and rotation angle of the 2 types of pedicle screws were calculated every 100 cycles to evaluate their resistance to migration and rotation. FEA was conducted to investigate the stress distribution and bone damage at the bone-screw interface for both types of pedicle screws. Biomechanical testing revealed that the pedicle screws with the undercut thread exhibited significantly lower vertical displacement and rotation angles than the pedicle screws with the V-shape thread (p <0.05). FEA results demonstrated a more uniform stress distribution in the bone surrounding the thread in the undercut design than in the V-shape design. Additionally, bone damage resulting from the pedicle screw was lower in the undercut design than in the V-shape design. Pedicle screws with an undercut thread are less prone to migration and rotation and thus more stable in the bone than those with a V-shape thread. The undercut thread design may reduce the incidence of pedicle-screw loosening. [ABSTRACT FROM AUTHOR]

There are two main surgical fixation methods for the posterior malleolar fractures (PMFs), the anterior-to-posterior (AP) screws or via the posterolateral (PL) approach utilizing a buttress plate. This review aims to compare the clinical outcome between the AP screw fixation and the PL plate fixation for treating PMFs. We searched all relevant publications about PMFs treated with AP screws or PL plates through electronic databases including the PubMed, the Cochrane Library, the Embase, the Wiley online library and the Web of Science. The meta-analysis was conducted to evaluated clinical outcomes including reduction quality, post-operative function and complications. Six studies (one single randomized controlled trial and five retrospective cohort studies) were enrolled. 172 patients underwent AP screw fixation and 214 patients underwent PL plate fixation with a total of 386 patients (169 males and 217 females). The PL plating group yielded better AOFAS scores(MD = 6.97, 95 % CI=[4.68, 9.27], P ＜0.00001, I2 =0 %) and was more likely to achieve excellent anatomical reduction(OR=5.49, 95 % CI=[1.06, 28.42], P = 0.04, I2 =80 %). No differences were found in the bad reduction quality, incidences of complications (arthritis, neuralgia, superficial wound healing problems and implant failure), the walking VAS scores and the dorsiflexion restriction degrees. We suggest that the PL plate fixation method has the clinical benefit of achieving anatomical reduction and better AOFAS scores over the AP screw fixation for treating PMFs. No differences were found in the incidences of complications (arthritis, neuralgia, superficial wound healing problems and implant failure), the walking VAS scores and the dorsiflexion restriction degrees. The posterior approach and the direct reduction are recommended for the treatment of the PMFs. Ⅱb [ABSTRACT FROM AUTHOR]

Background: Biocomposite screws reportedly provide equivalent graft fixation in anterior cruciate ligament reconstruction (ACLR) to metallic screws while simplifying subsequent imaging and surgery. One purported complication of biocomposite screws is paradoxical tunnel widening. Previous studies on beta-tricalcium phosphate screws have only reported outcomes at short- and midterm follow-up. Purpose: To radiographically assess the tibial tunnel 10 years after ACLR using hamstring tendon autografts and biocomposite interference screws in anatomic single-bundle (SB) and double-bundle (DB) methods. Study Design: Case series; Level of evidence, 4. Methods: Of the 105 initially recruited patients, 61 (58%) completed all follow-up evaluations for inclusion in this long-term study. A total of 26 patients received anatomic SB ACLR and 35 patients received DB ACLR with biocomposite interference screws containing beta-tricalcium phosphate in the tibia. Weightbearing anteroposterior and lateral radiographs of the index knee were taken in the early postoperative period and at 2, 5, and 10 years postoperatively; computed tomography (CT) imaging was performed at 10-year follow-up. Subjective and objective clinical assessments were recorded preoperatively and at 10-year follow-up. Results: The mean follow-up period was 122 months. In 76% of radiographs in the SB group, the width of the tibial tunnel had not increased at 10 years compared with the early postoperative period. The mean tibial tunnel volume on CT in the SB group was 2.04 cm3 (± 0.85 cm3). In the DB group, the posterolateral tunnel width had not increased in 69% of radiographs; the same was found in 63% of radiographs for the anteromedial tunnel at 10-year follow-up. The mean posterolateral tunnel volume on CT was 2.04 cm3 (±1.92 cm3) and the mean anteromedial tunnel volume was 1.38 cm3 (±0.54 cm3). There was no correlation between tunnel widths and KT-1000 arthrometer assessments. There was a moderate but statistically significant correlation between SB tibial tunnel volume on CT imaging and KT-1000 arthrometer anterior 134 N side-to-side difference (r = 0.45; P =.039). Conclusion: Most patients' tibial tunnels had not increased on 1 or both radiographic views at 10-year follow-up compared with the early postoperative period after ACLR using biocomposite interference screws, with no obvious negative effect on outcomes. However, the tunnels were still visible in most patients at 10 years on standard radiographs and CT imaging. [ABSTRACT FROM AUTHOR]

Background: Tibial bone tunnel widening (TW) is a common postoperative phenomenon after anterior cruciate ligament reconstruction (ACLR). Purpose: To compare the physical, biomechanical, osteoinductive, and histological characteristics of 2 fabricated bioabsorbable interference screws: (1) a modified poly(l -lactide- co - d, l -lactide) and hydroxyapatite (mPLA/HA) screw and (2) a poly(l -lactide- co -glycolide) and β-tricalcium phosphate (PLGA/β-TCP) screw; and to evaluate the effect of the PLA/HA screw on ameliorating postoperative TW in a canine ACLR model. Study Design: Controlled laboratory study. Methods: In vitro, the physical and biomechanical properties of the mPLA/HA and PLGA/β-TCP screws were tested. The osteoinductive activity of the screws was studied by cell experiments. In vivo, ACLR was performed on 48 beagle dogs, divided into the mPLA/HA group and the PLGA/β-TCP group. The femoral and tibial ends of the graft were both fixed with screws. Six animals in each group were sacrificed after live computed tomography (CT) scanning at 1, 3, 6, and 12 months postoperatively. For six knee samples of each group, three knee samples underwent biomechanical testing, and 1 of them, along with the other 3 samples, underwent micro-CT and histological examination to evaluate tibial TW. Results: The mPLA/HA screw exhibited better particle dispersion, bending strength, desirable self-locking effect, and optimized degradation behavior both in vivo and in vitro. Histologically, the mPLA/HA screw had comparative osteoinductive activity. There was good screw-bone integration using the mPLA/HA screw, while most fibrous scar healing was in the PLGA/β-TCP group. There were significant differences between the mPLA/HA and PLGA/β-TCP groups in tibial bone tunnel diameter at the screw body (6 months postoperatively: 5.09 ± 0.44 vs 7.12 ± 0.67; 12 months postoperatively: 4.83 ± 0.27 vs 6.23 ± 0.56; P <.01 for both) and the screw tail (6 months postoperatively: 4.84 ± 0.28 vs 5.97 ± 0.73; 12 months postoperatively: 4.77 ± 0.29 vs 5.92 ± 0.56; P <.01 for both). Conclusion: Compared with the PLGA/β-TCP screw commonly used in clinics at present, the mPLA/HA screw had comparative biosafety and mechanical properties, satisfactory biomechanical properties, and osteoinductive activity in vivo and in vitro. It effectively ameliorated the postoperative tibial TW in a canine ACLR model and increased the quality of screw-bone integration. Clinical Relevance: The good mechanical and biological properties of the mPLA/HA screws may provide an option to reduce the incidence of complications after ACLR. [ABSTRACT FROM AUTHOR]

Purpose: To comprehensively analyze the palatal thickness of soft tissues and determine optimal regions for the placement of palatal orthodontic miniscrews. Methods: Cone-beam computed tomography (CBCT) images on the coronal plane were obtained from 60 patients (30 female, 30 male; age range 19–45; mean age 32 ± 11), with 3-mm intervals in the regions of the canine (Ca), first premolar (Pr1), second premolar (Pr2), midpoint between the first and second molars (M1-M2), first molar (M1), second molar (M2) and midpalate. Results: The mucosal thickness measurements between the teeth showed significantly greater thickness in the Ca region at the 3 mm point, in the Pr1 region at the 6 mm point, and in the Pr2 region at the 9 and 12 mm points. At the 9 mm point, the Pr1 region demonstrated greater thickness than the M1-M2 whereas the Pr2 region was thicker than the M1 and M1-M2 regions. At the 12 and 15 mm points, the thickness increased from anterior to posterior: the Pr1 region was thinner than the Pr2, M1, and M2 regions and the Pr2 region was thinner than the M2 region. A schematization was devised for the optimal areas recommended for miniscrews in the palatal region. Conclusion: The mucosal thickness in the palatal region increases from anterior to posterior except the midpalatal region. Based on the results, in terms of soft tissue, the most suitable place for miniscrew placement is 6 mm from the gingival margin of the teeth and in the median portion of the palate. The findings may guide clinicians in choosing the optimal sites for palatal mini-implants. [ABSTRACT FROM AUTHOR]

Background: In comparison to titanium screws, novel cortical bone allograft screws may come with advantages in osseointegration and with avoidance of potential material removal surgery after scarf osteotomy. Methods: A scarf osteotomy with allograft bone screws as fixation was performed in 21 patients (30 feet). Clinical and radiological parameters were prospectively collected until one year after surgery. A retrospective control group, consisting of 75 patients (82 feet) after scarf osteotomy using headless compression screws, was used to compare clinical outcomes. Results: After fixation with allograft bone screws, the mean preoperative AOFAS score increased from 51.5 points preoperatively to 93.5 points one year after surgery. In radiological assessments, a continuous osseointegration with the remodeling of the bone screw was observed in all patients that finished follow-up. However, four metatarsal fractures occurred early postoperatively after fixation using allograft bone screws. There were only three material removal surgeries in patients treated with headless compression screws. Conclusions: Allograft bone screws display a safe fixation and are a biological alternative for scarf osteotomy. Enough distance between the screw and the proximal osteotomy should be ensured to avoid fractures. [ABSTRACT FROM AUTHOR]

This article reviews the research and development focus of metallic glasses in the field of biomedical applications. Metallic glasses exhibit a short-range ordered and long-range disordered glassy structure at the microscopic level, devoid of structural defects such as dislocations and grain boundaries. Therefore, they possess advantages such as high strength, toughness, and corrosion resistance, combining characteristics of both metals and glasses. This novel alloy system has found applications in the field of biomedical materials due to its excellent comprehensive performance. This review discusses the applications of Ti-based bulk metallic glasses in load-bearing implants such as bone plates and screws for long-term implantation. On the other hand, Mg-based metallic glasses, owing to their degradability, are primarily used in degradable bone nails, plates, and vascular stents. However, metallic glasses as biomaterials still face certain challenges. The Young's modulus value of Ti-based metallic glasses is higher than that of human bones, leading to stress-shielding effects. Meanwhile, Mg-based metallic glasses degrade too quickly, resulting in the premature loss of mechanical properties and the formation of numerous bubbles, which hinder tissue healing. To address these issues, we propose the following development directions: (1) Introducing porous structures into titanium-based metallic glasses is an important research direction for reducing Young's modulus; (2) To enhance the bioactivity of implant material surfaces, the surface modification of titanium-based metallic glasses is essential. (3) Developing antibacterial coatings and incorporating antibacterial metal elements into the alloys is essential to maintain the long-term effective antibacterial properties of metallic biomaterials. (4) Corrosion resistance must be further improved through the preparation of composite materials, while ensuring biocompatibility and safety, to achieve controllable degradation rates and degradation modes. [ABSTRACT FROM AUTHOR]

Background: Displaced femoral neck fractures are associated with a high revision rate. The new femoral neck system(FNS) offers advantages in fixation stability, potentially reducing the need for revision. The purpose of this study was to compare the revision rate of patients with different reduction quality treated with the FNS and cannulated screws (CS). Methods: This retrospective study included patients with Garden III or IV femoral neck fractures who underwent osteosynthesis in a level 1 trauma center between July 2019 and June 2023. A total of 141 cases met the inclusion criteria and received treatment with either the FNS (N = 65) or CS (N = 76). The quality of fracture reduction, surgical complications (such as femoral neck shortening, avascular necrosis of femoral head, nonunion of fracture, implant failure and withdrawal), revision surgery and the reasons for revision were analyzed. Results: The mean age of the 141 cases was 52.0 years (range 18–65); with sixty-five cases being male (46.1%). Eighty-four fractures (59.6%) were classified as Garden type III. Reduction quality was good in 71 cases (50.4%) and fair in 70 cases. The mean follow-up period was 25.9 months (range 12–46). A total of 26 cases(18.4%) underwent revision surgery. The revision rate in cases with good reduction was 11.3% (8/71 cases), with seven cases (four hardware removal and three arthroplasty) in the CS group and one case (arthroplasty for fracture nonunion and implant failure) in the FNS group, a significant difference was found between the two groups(P = 0.041). Among the 18 cases (25.7%, 18/70) with fair reduction who underwent revision surgery, nine cases (six hardware removal and three arthroplasty) in the CS group, and nine cases (arthroplasty for implant failure and cut-out) in the FNS group, and there was no significant difference between the two groups (P = 0.672). The total revision rate between the FNS group (15.4%, 10/65) and the CS group (21.1%, 16/76) was not significantly different (P = 0.387). Conclusions: The total revision rate between the FNS and CS group showed no difference. However, in cases with good reduction, the revision rate was lower in the FNS group compared to the CS group. [ABSTRACT FROM AUTHOR]

Background: In modern Hybrid ORs, the synergies of navigation and robotics are assumed to contribute to the optimisation of the treatment in trauma, orthopaedic and spine surgery. Despite promising evidence in the area of navigation and robotics, previous publications have not definitively proven the potential benefits. Therefore, the aim of this retrospective study was to evaluate the potential benefit and clinical outcome of patients treated in a fully equipped 3D-Navigation Hybrid OR. Methods: Prospective data was collected (March 2022- March 2024) after implementation of a fully equipped 3D-Navigation Hybrid OR ("Robotic Suite") in the authors level 1 trauma centre. The OR includes a navigation unit, a cone beam CT (CBCT), a robotic arm and mixed reality glasses. Surgeries with different indications of the spine, the pelvis (pelvic ring and acetabulum) and the extremities were performed. Spinal and non-spinal screws were inserted. The collected data was analysed retrospectively. Pedicle screw accuracy was graded according to the Gertzbein and Robbins (GR) classification. Results: A total of n = 210 patients (118 m:92f) were treated in our 3D-Navigation Hybrid OR, with 1171 screws inserted. Among these patients, 23 patients (11.0%) arrived at the hospital via the trauma room with an average Injury Severity Score (ISS) of 25.7. There were 1035 (88.4%) spinal screws inserted at an accuracy rate of 98.7% (CI95%: 98.1-99.4%; 911 GR-A & 111 GR-B screws). The number of non-spinal screws were 136 (11.6%) with an accuracy rate of 99.3% (CI95%: 97.8-100.0%; 135 correctly placed screws). This resulted in an overall accuracy rate of 98.8% (CI95%: 98.2-99.4%). The robotic arm was used in 152 cases (72.4%), minimally invasive surgery (MIS) was performed in 139 cases (66.2%) and wound infection occurred in 4 cases (1,9%). Overall, no revisions were needed. Conclusion: By extending the scope of application, this study showed that interventions in a fully equipped 3D-Navigation Hybrid OR can be successfully performed not only on the spine, but also on the pelvis and extremities. In trauma, orthopaedics and spinal surgery, navigation and robotics can be used to perform operations with a high degree of precision, increased safety, reduced radiation exposure for the OR-team and a very low complication rate. [ABSTRACT FROM AUTHOR]

Spectral Photon Counting Computed Tomography (SPCCT), a ground-breaking development in CT technology, has immense potential to address the persistent problem of metal artefacts in CT images. This study aims to evaluate the potential of Mars photon-counting CT technology in reducing metal artefacts. It focuses on identifying and quantifying clinically significant materials in the presence of metal objects. A multi-material phantom was used, containing inserts of varying concentrations of hydroxyapatite (a mineral present in teeth, bones, and calcified plaque), iodine (used as a contrast agent), CT water (to mimic soft tissue), and adipose (as a fat substitute). Three sets of scans were acquired: with aluminium, with stainless steel, and without a metal insert as a reference dataset. Data acquisition was performed using a Mars SPCCT scanner (Microlab 5×120); operated at 118 kVp and 80 μA. The images were subsequently reconstructed into five energy bins: 7-40, 40-50, 50-60, 60-79, and 79-118 keV. Evaluation metrics including signal-to-noise ratio (SNR), linearity of attenuation profiles, root mean square error (RMSE), and area under the curve (AUC) were employed to assess the energy and material-density images with and without metal inserts. Results show decreased metal artefacts and a better signal-to-noise ratio (up to 25%) with increased energy bins as compared to reference data. The attenuation profile also demonstrated high linearity (R2 >0.95) and lower RMSE across all material concentrations, even in the presence of aluminium and steel. Material identification accuracy for iodine and hydroxyapatite (with and without metal inserts) remained consistent, minimally impacting AUC values. For demonstration purposes, the biological sample was also scanned with the stainless steel volar implant and cortical bone screw, and the images were objectively assessed to indicate the potential effectiveness of SPCCT in replicating real-world clinical scenarios. [ABSTRACT FROM AUTHOR]

Background: In acetabular fracture surgery, understanding the biomechanical behaviour of fractures and implants is beneficial for clinical decision-making about implant selection and postoperative (early) weightbearing protocols. This study outlines a novel approach for creating finite element models (FEA) from actual clinical cases. Our objectives were to (1) create a detailed semi-automatic three-dimensional FEA of a patient with a transverse posterior wall acetabular fracture and (2) biomechanically compare patient-specific implants with manually bent off-the-shelf implants. Methods: A computational study was performed in which we developed three finite element models. The models were derived from clinical imaging data of a 20-year-old male with a transverse posterior wall acetabular fracture treated with a patient-specific implant. This implant was designed to fit the patient's anatomy and fracture configuration, allowing for optimal placement and predetermined screw trajectories. The three FEA models included an intact hemipelvis for baseline comparison, one with a fracture fixated with a patient-specific implant, and another with a conventional implant. Two loading conditions were investigated: standing up and peak walking forces. Von Mises stress and displacement patterns in bone, implants and screws were analysed to assess the biomechanical behaviour of fracture fixation with either a patient-specific versus a conventional implant. Results: The finite element models demonstrated that for a transverse posterior wall type fracture, a patient-specific implant resulted in lower peak stresses in the bone (30 MPa and 56 MPa) in standing-up and peak walking scenario, respectively, compared to the conventional implant model (46 MPa and 90 MPa). The results suggested that patient-specific implant could safely withstand standing-up and walking after surgery, with maximum von Mises stresses in the implant of 156 MPa and 371 MPa, respectively. The results from the conventional implant indicate a likelihood of implant failure, with von Mises stresses in the implant (499 MPa and 1000 MPa) exceeding the yield stress of stainless steel. Conclusion: This study presents a workflow for conducting finite element analysis of real clinical cases in acetabular fracture surgery. This concept of personalized biomechanical fracture and implant assessment can eventually be applied in clinical settings to guide implant selection, compare conventional implants with innovative patient-specific ones, optimizing implant designs (including shape, size, materials, screw positions), and determine whether immediate full weight-bearing can be safely permitted. [ABSTRACT FROM AUTHOR]

Objective: To retrospectively analyze and assess the long-term effectiveness of robotic navigation and traditional closed reduction internal fixation in the treatment of Delbet type II femoral neck fracture in children. Methods: A total of fifty-five patients diagnosed with pediatric Delbet type II femoral neck fracture, who were admitted to Foshan Hospital of Traditional Chinese Medicine between January 2018 and June 2022, were included in this study. Among them, 22 cases of nailing under robotic navigation were set as the observation group, and 33 cases of nailing under fluoroscopy of the C-arm machine were set as the control group. All patients had their femoral neck fractures closed and repositioned first. After confirming the satisfactory fracture repositioning under the fluoroscopic view of the C-arm machine, internal fixation was performed by inserting hollow compression screws in the corresponding surgical way.A comparative analysis was conducted between the two groups to assess the disparity in the amount of X-ray exposure during surgery, the number of guide pins inserted, and the duration of the surgical procedure. The quality of comparative fracture reduction was assessed according to the Haidukewych criteria on the first postoperative hip X-ray, and the parallelism and distribution of the comparative screws were measured. The incidence of hip function and postoperative complications according to the Ratliff criteria were evaluated between each of the subgroups at the final follow-up. Results: Comparison of general information, operation duration, and quality of fracture reduction between the two groups failed to reveal statistically significant results (P > 0.05). The observation group had a lower number of X-ray exposures and guide pin placements compared to the control group, and this difference was statistically significant (P < 0.05).At the last follow-up, the observation group exhibited superior screw parallelism and distribution, as well as hip joint function, compared to the control group, and this difference was statistically significant (P < 0.05). The incidence of complications in the observation group was lower than that in the control group; however, the difference was not statistically significant (P > 0.05). Conclusion: Closed reduction and internal fixation under orthopedic robot navigation can achieve better long-term efficacy in treating Delbet type II femoral neck fracture in children. [ABSTRACT FROM AUTHOR]

Background: Thin lateral femoral wall has been investigated as a sign of instability in trochanteric hip fractures, necessitating lateral wall reconstruction or the use of a cephalomedullary nail (CMN). Various cut-off values have been proposed to guide implant choice. This review aims to determine the clinical significance of the lateral femoral wall thickness (LWT) in trochanteric hip fractures and identify an optimal cut-off value for increased risk of lateral wall (LW) fracture when using Dynamic Hip Screw (DHS). Methods: A comprehensive search was conducted in databases including Medline, Embase, and the Cochrane library up to July 2023. A predefined strategy was employed, with 5 eligible studies critically appraised using the methodological index for non-randomized studies (MINORS) criteria. Outcomes assessed encompassed the standardised mean difference (SMD) of LWT between the LW fracture and non LW fracture groups, aggregate LWT mean in LW fracture group, and the relation between AO/OTA fracture type with LW fracture utilising the chi-square test. Results: Among 481 patients from 5 studies, 112 experienced LW fractures, while 369 did not postoperatively. Analysis indicated a significantly lower LWT in the LW fracture group (SMD −1.13, I² = 41.3%, p = 0.146). The mean LWT in the LW fracture group was 18.2 mm, with a 95% confidence interval of 17.29–19.10 mm. Conclusions: A preoperative thin lateral femoral wall is a critical predictor of fixation failure and suboptimal functional outcomes when using a DHS. Thorough evaluation of pre- and intraoperative x-rays is essential. CMN is recommended over DHS in cases with LWT measurements <19 mm. [ABSTRACT FROM AUTHOR]

The present endeavour numerically exploits the use of a phase-field model to simulate and investigate fracture patterns, deformation mechanisms, damage, and mechanical responses in a human vertebra after the incision of pedicle screws under compressive regimes. Moreover, the proposed phase field framework can elucidate scenarios where different damage patterns, such as crack nucleation sites and crack trajectories, play a role after the spine fusion procedure, considering several simulated physiological movements of the vertebral body. Spatially heterogeneous elastic properties and phase field parameters have been computationally derived from bone density estimation. A convergence analysis has been conducted for the vertebra-screws model, considering several mesh refinements, which has demonstrated good agreement with the existing literature on this topic. Consequently, by assuming different angles for the insertion of the pedicle screws and taking into account a few vertebral motion loading regimes, a plethora of numerical results characterizing the damage occurring within the vertebral model has been derived. Overall, the phase field results confirm and enrich the current literature, shed light on the medical community, which will be useful in enhancing clinical interventions and reducing post-surgery bone failure and screw loosening. The proposed computational approach also investigates the effects in terms of fracture and mechanical behaviour of the vertebral-screws body within different metastatic lesions opening towards major life threatening scenarios. [ABSTRACT FROM AUTHOR]

To evaluate the feasibility of a novel method for occipitocervical fixation (OCF) through the endonasal corridor. Thin-cut computed tomography scans were obtained for 5 cadaveric specimens. Image segmentation was used to reconstruct 3D models of each O-C1 joint complex. Using computer-aided design software, plates were custom-designed to span each O-C1 joint, sit flush onto the bony surface, and accommodate screws. The final models were 3D-printed in titanium. For implantation, specimens were held in pin-fixation and registered to neuronavigation. A rigid 0º endoscope was used for endonasal visualization. An inverted U-shaped nasopharyngeal flap was raised to expose the occipital condyles and C1. The plates were introduced and fixed with bone screws. Computed tomography scans were obtained to assess screw accuracy and proximity to critical neurovascular structures. Screw entry points and trajectories were recorded. Endonasal OCF was performed on 5 cadaveric specimens. The mean starting point for occipital condyle screws was 6.17 mm lateral and 5.38 mm rostral to the medial O-C1 joint. Mean axial and sagittal trajectories were 7.98° and 6.71°, respectively. The mean starting point for C1 screws was 16.11 mm lateral to the C1 anterior tubercle and 6.39 mm caudal to the medial O-C1 joint. Mean axial and sagittal trajectories were 10.97° and −9.91°, respectively. Endonasal OCF is technically and anatomically feasible. The application of this technique may allow for same-stage endonasal decompression and fixation, offering a minimally invasive alternative to current methods of fixation and advancing surgeons' ability to treat pathology of the craniovertebral junction. Next steps will focus on biomechanical testing. [ABSTRACT FROM AUTHOR]

This study compares the effectiveness of virtual reality simulators (VRS) and a saw bone model for learning lumbar pedicle screw insertion (LPSI) in neurosurgery. A single-center, cross-sectional, randomized controlled laboratory investigation was conducted involving residents and fellows from a tertiary care referral hospital. Participants were divided into two groups (A and B). Group A performed 3 LPSI tasks: the first on a saw bone model, the second on VRS, and the third on another saw bone model. Group B completed 2 LPSI tasks: the first on a saw bone model and the second on another saw bone model. The accuracy of LPSI was evaluated through noncontrast computed tomography scans for the saw bone models, while the in-built application of VRS was utilized to check for accuracy of screw placement using the simulator. The study included 38 participants (19 in each group). Group A participants showed reduced mean entry point error (0.11 mm, P 0.024), increased mean purchase length (4.66 cm, P 0.007), and no cortical breaches (P 0.031) when placing the second saw bone model screw. Similar improvements were observed among group A participants in PGY 1–3 while placing the second saw bone model screws. Virtual reality simulators (VRS) prove to be an invaluable tool for teaching complex neurosurgical skills, such as LPSI, to trainees. This technology investment can enhance the learning curve while maintaining patient safety. [ABSTRACT FROM AUTHOR]

Hydroxyapatite (HA) reinforced polylactic acid (PLA) composite is the most investigated material for biodegradable implant applications such as screws and plates. The objective of this work is to test hypothesis of distribution of HA in PLA composite influence on the variations in the properties of the composites. Investigation was done for the distribution of HA in PLA injection mould (IM) composites for the various concentrations (2 to 8 wt.%) and their effect on mechanical properties such as flexural and tensile test. Proportionate quantity of HA was introduced at fixed intervals in a twin screw extruder for the preparation of PLA composites pellets containing in various wt.% of HA. The distribution of HA in IM PLA composite specimens was analysed by elemental mapping using scanning electron microscope (SEM) and also by estimation of residue (HA) after burn out test of sampling of specimens. Differential scanning calorimetry (DSC) was used for the study of effect of HA in PLA composites. The value of standard deviations of mechanical properties, taken as a rudimentary measure of reliability of IM PLA-HA composites, was found to have influence from the distributions of HA. Among the composites studied, PLA-HA composite with 4 and 5 HA wt.% found exhibiting reliable mechanical property due to crystallinity of 31.83% and a comparatively better homogenous dispersion of HA in PLA. A case study of distribution of HA in a product, namely, bone screw, promulgated the issues of IM PLA-HA composites for biomedical applications. [ABSTRACT FROM AUTHOR]