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Objective: Surgical treatment of degenerative lumbar spondylolisthesis (DLS) reliably improves patient-reported quality of life; however, patient population heterogeneity, in addition to other factors, ensures ongoing equipoise in choosing the ideal surgical treatment. Surgeon preference for fusion or decompression alone influences surgical treatment decision-making. Meanwhile, at presentation, patient-reported outcome measures (PROMs) differ considerably between females and males. The aims of this study were to determine whether there exists a difference in the rates of decompression and fusion versus decompression alone based on patient-reported sex, and to determine if widely accepted indications for fusion justify any observed differences or if surgeon preference plays a role., Methods: This study is a retrospective cohort analysis of patients enrolled in the Canadian Spine Outcomes Research Network (CSORN) DLS study, a multicentered Canadian prospective study, investigating the surgical management and outcome of DLS. Decompression and fusion rates, patient characteristics, preoperative PROMs, and radiographic measures were compared between males and females before and after propensity score matching., Results: In the unmatched cohort, female patients were more likely to undergo decompression and fusion than male patients. Females were more likely to have the recognized indications for fusion, including kyphotic disc angle, higher spondylolisthesis grade and slip percentage, and patient-reported back pain. Other radiographic findings associated with the decision to fuse, including facet effusion, facet distraction, or facet angle, were not more prevalent in females. After propensity score matching for demographic and radiographic characteristics, similar proportions of male and female patients underwent decompression and fusion and decompression alone., Conclusions: Although it remains unclear who should or should not undergo fusion, in addition to surgical decompression of DLS, female patients undergo fusion at a higher rate than their male counterparts. After matching baseline radiographic factors indicating fusion, this analysis showed that the decision to fuse was not biased by sex differences. Rather, the higher proportion of females undergoing fusion is largely explained by the radiographic and clinical indications for fusion, suggesting that specific clinical and anatomical features of this condition are indeed different between sexes.

Background Context: Degenerative lumbar spondylolisthesis (DLS) is a debilitating condition associated with poor preoperative functional status. Surgical intervention has been shown to improve functional outcomes in this population though the optimal surgical procedure remains controversial. The importance of maintaining and/or improving sagittal and pelvic spinal balance parameters has received increasing interest in the recent DLS literature. However, little is known about the radiographic parameters most associated with improved functional outcomes among patients undergoing surgery for DLS., Purpose: To identify the effect of postoperative sagittal spinal alignment on functional outcome after DLS surgery., Study Design: Retrospective cohort study., Patient Sample: Two-hundred forty-three patients in the Canadian Spine Outcomes and Research Network (CSORN) prospective DLS study database., Outcome Measures: Baseline and 1-year postoperative leg and back pain on the 10-point Numeric Rating Scale and baseline and 1-year postoperative disability on the Oswestry Disability Index (ODI)., Methods: All enrolled study patients had a DLS diagnosis and underwent decompression in isolation or with posterolateral or interbody fusion. Global and regional radiographic alignment parameters were measured at baseline and 1-year postoperatively including sagittal vertical axis (SVA), pelvic incidence and lumbar lordosis (LL). Both univariate and multiple linear regression was used to assess for the association between radiographic parameters and patient-reported functional outcomes with adjustment for possible confounding baseline patient factors., Results: Two-hundred forty-three patients were available for analysis. Among participants, the mean age was 66 with 63% (153/243) female with the primary surgical indication of neurogenic claudication in 197/243 (81%) of patients. Worse pelvic incidence-LL mismatch was correlated with more severe disability [ODI, 0.134, p<.05), worse leg pain (0.143, p<.05) and worse back pain (0.189, p<.001) 1-year postoperatively. These associations were maintained after adjusting for age, BMI, gender, and preoperative presence of depression (ODI, R 2 0.179, β, 0.25, 95% CI 0.08, 0.42, p=.004; back pain R 2 0.152 (β, 0.05, 95% CI 0.022, 0.07, p<.001; leg pain score R 2 0.059, β, 0.04, 95% CI 0.008, 0.07, p=.014). Likewise, reduction of LL was associated with worse disability (ODI, R 2 0.168, β, 0.04, 95% CI -0.39, -0.02, p=.027) and worse back pain (R 2 0.135, β, -0.04, 95% CI -0.06, -0.01, p=.007). Worsened SVA correlated with worse patient reported functional outcomes (ODI, R 2 0.236, β, 0.12, 95% CI 0.05, 0.20, p=.001). Similarly, an increase (worsening) in SVA resulted in a worse NRS back pain (R 2 0.136, β, 0.01, 95% CI .001, 0.02, p=.029) and worse NRS leg pain (R 2 0.065, β, 0.02, 95% CI 0.002, 0.02, p=.018) scores regardless of surgery type., Conclusions: Preoperative emphasis on regional and global spinal alignment parameters should be considered in order to optimize functional outcome in lumbar degenerative spondylolisthesis treatment., Competing Interests: Declarations of competing interests One or more of the authors declare financial or professional relationships on ICMJE-TSJ disclosure forms., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Background Context: Preoperative expectations influence postoperative outcomes. Patients with lumbar degenerative spondylolisthesis have especially high expectations of pain relief and overall functional well-being compared to patients with lumbar stenosis., Purpose: The primary objective was to analyze preoperative expectations of lumbar DS patients with respect to the type of surgery proposed (decompression vs decompression and fusion). Secondarily, we aimed to assess the associations between preoperative expectations and patient and clinical factors as well as postoperative expectations fulfillment., Study Design/setting: Patients were prospectively enrolled in a multicenter, prospective cohort study evaluating the assessment and management of degenerative spondylolisthesis utilizing the infrastructure of the Canadian Spine Outcomes and Research Network (CSORN) surgical registry., Patient Sample: Patients with a diagnosis of degenerative spondylolisthesis with symptoms of neurogenic claudication or radiculopathy with or without back pain, unresponsive to nonoperative management over at least 3 months were included. Patients who underwent decompression, decompression and posterolateral fusion or decompression and interbody fusion at Canadian spine centers between January 2015 and September 2021 were included., Outcome Measures: The North American Spine Society Lumbar Spine Questionnaire was utilized for expectations measurement. The expectation questionnaire was completed following consent and before surgery and at 1 year., Methods: Expectations for pain relief and improvements in overall functional well-being were rated on a scale of 0 to 100. Preoperative expectation in terms of pain relief and functional well-being score were calculated. Multivariate linear regression was used to evaluate the association between expected preoperative patient factors and pain relief and functional well-being. The factors associated with the most important expectation were evaluated using multivariable multinomial logistic regression., Results: Three hundred fifty-two patients were included with 100 patients undergoing decompression and 252 patients also undergoing fusion. The seven items of preoperative expectations did not differ between the procedure groups nor did expected change. The mean pain relief and overall functional well-being expectation scores did not significantly differ between procedures. Higher expectations were associated with having more comorbidities [β=-2.0 (SE 0.8), p=.020], being physically active [β=8.4 (SE 3.2), p=.010] and having more leg pain [β=1.6 (SE 0.7), p=.015]. Better perceived physical health measured by SF12 PCS was associated with lower expectation of pain relief [β= -0.4 (SE 0.2), p=.039] and functional well-being [β=-0.84 (SE 0.2), p=.001]. Better perceived mental health measured by SF12 MCS was associated with lower expectation of functional well-being [β=-0.8 (SE 0.2), p=.001]. Postoperative expectations fulfillment did not differ between procedures., Conclusion: Preoperative expectations in terms of pain relief and functional well-being were similar between the two most common procedures performed, decompression ± fusion. Secondarily, higher preoperative expectations were associated with greater pain, disability and being physically active. Expectations fulfillment did not differ between procedures., (Copyright © 2023 Elsevier Inc. All rights reserved.)

We conducted a systematic review with meta-analysis and qualitative synthesis. This study aims to characterize pseudarthrosis after long-segment fusion in spinal deformity by identifying incidence rates by etiology, risk factors for its development, and common features. Pseudarthrosis can be a painful and debilitating complication of spinal fusion that may require reoperation. It is poorly characterized in the setting of spinal deformity. The MEDLINE, EMBASE, and Cochrane databases were searched for clinical research including spinal deformity patients treated with long-segment fusions reporting pseudarthrosis as a complication. Meta-analysis was performed on etiologic subsets of the studies to calculate incidence rates for pseudarthrosis. Qualitative synthesis was performed to identify characteristics of and risk factors for pseudarthrosis. The review found 162 articles reporting outcomes for 16,938 patients which met inclusion criteria. In general, the included studies were of medium to low quality according to recommended reporting standards and study design. Meta-analysis calculated an incidence of 1.4% (95% CI 0.9-1.8%) for pseudarthrosis in adolescent idiopathic scoliosis, 2.2% (95% CI 1.3-3.2%) in neuromuscular scoliosis, and 6.3% (95% CI 4.3-8.2%) in adult spinal deformity. Risk factors for pseudarthrosis include age over 55, construct length greater than 12 segments, smoking, thoracolumbar kyphosis greater than 20°, and fusion to the sacrum. Choice of graft material, pre-operative coronal alignment, post-operative analgesics, and sex have no significant impact on fusion rates. Older patients with greater deformity requiring more extensive instrumentation are at higher risk for pseudarthrosis. Overall incidence of pseudarthrosis requiring reoperation is low in adult populations and very low in adolescent populations.

Background Context: Transforaminal lumbar interbody fusion (TLIF) is a widely accepted surgical procedure, but cage migration (CM) and cage retropulsion (CR) are associated with poor outcomes., Purpose: This study seeks to identify risk factors associated with these serious events., Study Design: A prospective observational longitudinal study., Patient Sample: Over a 5-year period, 881 lumbar levels in 784 patients were treated using TLIF at three spinal surgery centers., Outcome Measures: We evaluated the odds ratio of the risk factors for CM with and without subsidence and CR in multivariate analysis., Methods: Our study classified CM into two subgroups: CM without subsidence and CM with subsidence. Cases of spinal canal and/or foramen intrusion of the cage was defined separately as CR. Patient records, operative notes, and radiographs were analyzed for factors potentially related to CM with subsidence, CM without subsidence, and CR., Results: Of 881 lumbar levels treated with TLIFs, CM without subsidence was observed in 20 (2.3%) and CM with subsidence was observed in 36 (4.1%) patients. Among the CM cases, CR was observed in 17 (17/56, 30.4%). The risk factors of CM without subsidence were osteoporosis (OR 8.73, p < .001) and use of a unilateral single cage (OR 3.57, p < .001). Osteoporosis (OR 5.77, p < .001) and endplate injury (OR 26.87, p < .001) were found to be significant risk factors for CM with subsidence. Risk factors of CR were osteoporosis (OR 7.86, p < .001), pear-shaped disc (OR 8.28, p = .001), endplate injury (OR 18.70, p < .001), unilateral single cage use (OR 4.40, p = .03), and posterior cage position (OR 6.45, p = .04). A difference in overall fusion rates was identified, with a rate of 97.1% (801 of 825) for no CM, 55.0% (11 of 20) for CM without subsidence, 41.7% (15 of 36) for CM with subsidence, and 17.6% (3 of 17) for CR at 1.5 years postoperatively., Conclusions: Our results suggest that osteoporosis is a significant risk factor for both CM and CR. In addition, a pear-shaped disc, posterior positioning of the cage, the presence of endplate injury and the use of a single cage were correlated with the CM with and without subsidence and CR., (Copyright © 2018 Elsevier Inc. All rights reserved.)

OBJECTIVE The study aimed to determine if the intraoperative segmental lordosis (as calculated on a cross-table lateral radiograph following a single-level transforaminal lumbar interbody fusion [TLIF] for degenerative spondylolisthesis/low-grade isthmic spondylolisthesis) is maintained at discharge and at 6 months postsurgery. METHODS The authors reviewed images and medical records of patients ≥ 16 years of age with a diagnosis of an isolated single-level, low-grade spondylolisthesis (degenerative or isthmic) with symptomatic spinal stenosis treated between January 2008 and April 2014. Age, sex, surgical level, surgical approach, and facetectomy (unilateral vs bilateral) were recorded. Upright standardized preoperative, early, and 6-month postoperative radiographs, as well as intraoperative lateral radiographs, were analyzed for the pelvic incidence, segmental lumbar lordosis (SLL) at the TILF level, and total LL (TLL). In addition, the anteroposterior position of the cage in the disc space was documented. Data are presented as the mean ± SD; a p value < 0.05 was considered significant. RESULTS Eighty-four patients were included in the study. The mean age of patients was 56.8 ± 13.7 years, and 46 patients (55%) were men. The mean pelvic incidence was 59.7° ± 11.9°, and a posterior midline approach was used in 47 cases (56%). All TLIF procedures were single level using a bullet-shaped cage. A bilateral facetectomy was performed in 17 patients (20.2%), and 89.3% of procedures were done at the L4-5 and L5-S1 segments. SLL significantly improved intraoperatively from 15.8° ± 7.5° to 20.9° ± 7.7°, but the correction was lost after ambulation. Compared with preoperative values, at 6 months the change in SLL was modest at 1.8° ± 6.7° (p = 0.025), whereas TLL increased by 4.3° ± 9.6° (p < 0.001). The anteroposterior position of the cage, approach, level of surgery, and use of a bilateral facetectomy did not significantly affect postoperative LL. CONCLUSIONS Following a single-level TLIF procedure using a bullet-shaped cage, the intraoperative improvement in SLL is largely lost after ambulation. The improvement in TLL over time is probably due to the decompression part of the procedure. The approach, level of surgery, bilateral facetectomy, and position of the cage do not seem to have a significant effect on LL achieved postoperatively.

Facet injuries are common in the cervical spine. Many classification systems over the years have characterized the heterogeneity of these injuries. For unilateral facet fractures with minimal displacement and no neurological deficit, there is mounting evidence that better radiographic and clinical outcomes may be achieved with surgical treatment. Anterior and posterior approaches can both be utilized successfully for the surgical management of facet injuries. The anterior approach is well tolerated, allows one to address a disc herniation, and provides a high union rate with good sagittal alignment. The posterior approach allows for easier open reduction and biomechanically superior fixation., (Copyright © 2016 Elsevier Inc. All rights reserved.)

OBJECTIVE The objective of this study was to determine if there is a significant difference in surgical site infection (SSI) when comparing the Wiltse and midline approaches for posterior instrumented interbody fusions of the lumbar spine and, secondarily, to evaluate if the reoperation rates and specific causes for reoperation were similar for both approaches. METHODS A total of 358 patients who underwent 1- or 2-level posterior instrumented interbody fusions for degenerative lumbar spinal pathology through either a midline or Wiltse approach were prospectively followed between March 2005 and January 2011 at a single tertiary care facility. A retrospective analysis was performed primarily to evaluate the incidence of SSI and the incidence and causes for reoperation. Secondary outcome measures included intraoperative complications, blood loss, and length of stay. A matched analysis was performed using the Fisher's exact test and a logistic regression model. The matched analysis controlled for age, sex, comorbidities, number of index levels addressed surgically, number of levels fused, and the use of bone grafting. RESULTS All patients returned for follow-up at 1 year, and adverse events were followed for 2 years. The rate of SSI was greater in the midline group (8 of 103 patients; 7.8%) versus the Wiltse group (1 of 103 patients; 1.0%) (p = 0.018). Fewer additional surgical procedures were performed in the Wiltse group (p = 0.025; OR 0.47; 95% CI 0.23-0.95). Proximal adjacent segment failure requiring reoperation occurred more frequently in the midline group (15 of 103 patients; 14.6%) versus the Wiltse group (6 of 103 patients; 5.8%) (p = 0.048). Blood loss was significantly lower in the Wiltse group (436 ml) versus the midline group (703 ml); however, there was no significant difference between the 2 groups in intraoperative complications or length of stay. CONCLUSIONS The patients who underwent the Wiltse approach had a decreased risk of wound breakdown and infection, less blood loss, and fewer reoperations than the midline patients. The risk of adjacent segment failure in short posterior constructs is lower with a Wiltse approach.

This study reviews the outcomes and revision rates of degenerative lumbar fusion surgery using cortical trajectory pedicle screws in lieu of traditional pedicle screw instrumentation. Pedicle screw fixation can be a challenge in patients with low bone mineral density. Wide posterior approaches to the lumbar spine exposing lateral to the facet joints and onto transverse processes causes an additional degree of muscular damage and blood loss not present with a simple laminectomy. A cortical bone trajectory pedicle screw has been proposed as an alternative to prevent screw pullout and decrease the morbidity associated with the wide posterior approach to the spine. We present a series of eight consecutive patients using a cortical bone trajectory instead of traditional pedicle screw fixation for degenerative conditions of the lumbar spine. A retrospective review of our institutional registry data identified eight patients who had cortical screws placed with the assistance of O-arm Stealth navigation (Medtronic Sofamor Danek, Memphis, TN, USA) from 2010-2013. We analyzed the need for revision, the maintenance of reduction and the incidence of screw pullout or breakage. Our review demonstrated that two of eight patients were revised at an average of 12months. The reasons for these revisions were pseudarthrosis and caudal adjacent segment failure. All patients who were revised had frank screw loosening. We present early clinical results of a new technique that has been shown to have a better fixation profile in laboratory testing. Our less than favorable early clinical results should be interpreted with caution and highlight important technical issues which should be considered., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Object: Unilateral facet injuries can be treated with either anterior or posterior fixation techniques with reportedly good outcomes. The two approaches have not been directly compared, however, and consensus is lacking as to which is the optimal method. The primary objective of this study was to determine whether acute postoperative morbidity differed between anteriorly and posteriorly treated patients with unilateral facet injuries., Methods: Forty-two patients were prospectively randomized to undergo either anterior cervical discectomy and fusion or posterior fixation. The primary outcome measure was the postoperative time required to achieve a predefined set of discharge criteria. Secondary outcome measures included postoperative pain, wound infections, radiographically demonstrated fusion and alignment, and patient-reported outcome measures., Results: The median time to achieve the discharge criteria was 2.75 and 3.5 days for anterior and posterior groups, respectively, a difference that did not reach statistical significance (p = 0.096). Compared with those treated using posterior fixation, anteriorly treated patients exhibited somewhat less postoperative pain, a lower rate of wound infection, a higher rate of radiographically demonstrated union, and better radiographically proven alignment. Nonetheless, the anterior approach was accompanied by a risk of swallowing difficulty in the early postoperative period. Patient-reported outcome measures did not reveal a difference between anterior and posterior fixation procedures., Conclusions: This prospective randomized controlled trial provided level 1 evidence that both the anterior and posterior fixation approaches appear to be valid treatment options. Although statistical significance was not reached in the primary outcome measure, some secondary outcome measures favored anterior fixation and others favored posterior treatment for unilateral facet injuries.

Study Design: Clinical case series., Objective: To describe a series of patients with progressive sagittal decompensation caused by failure at the caudal end of an instrumented lumbar fusion., Summary of Background Data: Lumbar kyphosis in association with global sagittal decompensation can be a disabling problem, particularly as a late complication of distraction instrumentation. Although kyphosis at the rostral end of instrumented fusions secondary to adjacent segment degeneration has been well described, substantially less has been documented about failure and kyphosis at the caudal end., Methods: Patients who have a progressive lumbar kyphosis and sagittal decompensation requiring operative revision were retrospectively reviewed, and radiographic measurements of lumbar lordosis and sagittal balance were performed to study this problem., Results: There were 13 patients identified. The most common mode of caudal junctional decompensation was related to failure of the most distal fixation. Sagittal decompensation occurred even in the presence of satisfactory lumbar lordosis. Revision surgery and improved sagittal balance were achieved typically using the technique of pedicle subtraction osteotomy and extension of the instrumentation to the sacrum. Osteoporosis, hip osteoarthritis, and substance abuse were commonly observed associations., Conclusions: Fixation failure at the caudal end of lumbar-instrumented fusion should be considered in patients with progressive sagittal decompensation. The high potential for failure of L5 pedicle screws after the index surgery warrants serious consideration of extending such fusions into the sacrum/ilium.

Study Design: An aneurysmal bone cyst in the neural arch of the fourth cervical vertebra of a 10-year-old girl is reported, along with a brief review of the literature on the topic., Objective: To report the presentation and diagnosis of this disorder along with a discussion of the major pitfalls of treatment., Summary of Background Data: An aneurysmal bone cyst occurs commonly in the second decade, with a predilection for the lumbar spine. With occurrence in the neural arch of a cervical vertebra, the potential for instability following surgical excision is high., Methods: A 10-year-old white female presented with neck pain of 3 months' duration. Diagnostic imaging revealed an expansile lytic lesion in the spinous process and lamina of the fourth cervical vertebra. Surgical treatment consisted of excisional biopsy and a segmental instrumented posterior fusion from C3-C5. The histopathology was consistent with an aneurysmal bone cyst., Results: Surgical excision consisting of laminectomy and instrumented segmental fusion provided a good clinical result, and minimized the risk and degree of the 2 most common complications: recurrence of the tumor; and postlaminectomy kyphosis, a frequent occurrence in the pediatric population., Conclusions: In pediatric patients who develop a bone tumor of the posterior elements of the cervical spine, careful clinical and radiologic evaluation is necessary to narrow the differential diagnosis. In most cases, a complete excision should be performed if possible. The risk of postlaminectomy kyphosis is high in the pediatric age population. As such, a fusion should be considered whenever a laminectomy is performed in the immature cervical spine. Risk factors for kyphosis include a high cervical level, multiple laminectomy levels, and postoperative irradiation.

Objective: A systematic review of the radiographic and clinical outcomes of adult patients undergoing surgery for low-grade isthmic spondylolisthesis was performed to determine whether conclusions could be made regarding the optimal choice of surgically managing adult low-grade isthmic spondylolisthesis., Methods: We tabulated the radiographic and clinical outcomes of patients who underwent a posterior procedure alone, an anterior procedure alone, or a combined anterior and posterior procedure. We also evaluated the influence of covariates such as laminectomy, spinal internal fixation, smoking, and secondary gain issues on these outcomes. Patients were pooled, and a chi analysis was performed to determine the relationship between surgical approach and patient outcome. A covariate analysis was performed to determine the influence of a laminectomy, spinal fixation, smoking, and secondary gain issues on these outcomes., Results: The available literature consisted primarily of retrospective case series, with only 4 of 34 reports being prospective randomized controlled studies. Patients with combined anterior and posterior procedures were most likely to achieve a solid fusion and a successful clinical outcome. The use of spinal fixation also increased the chance of fusion and successful clinical outcome., Conclusions: A pooling of the surgical literature on adult low-grade spondylolisthesis indicates that a combined anterior and posterior procedure most reliably achieves fusion and a successful clinical outcome. The literature, however, is primarily retrospective and heterogeneous with respect to indications for surgery and methods of evaluating outcome, providing a compelling rationale for a prospective randomized controlled trial of the various surgical approaches to this problem.

Study Design: Posterolateral lumbar fusions were performed in nicotine-exposed, New Zealand white rabbits. Animals that developed a pseudarthrosis were then regrafted with no graft, autograft, or osteogenic protein-1 (OP-1)., Objectives: To establish a model of pseudarthrosis repair and to evaluate the ability of OP-1 to induce fusion in this model., Summary of Background Data: OP-1 has been shown to have a 100% fusion rate in an established rabbit fusion model, even in the presence of nicotine, which is known to inhibit fusion., Methods: Forty-four New Zealand white rabbits underwent posterolateral lumbar fusion with iliac crest autograft. To maximize the incidence of pseudarthroses, nicotine was administered to all rabbits. At 5 weeks, the spines were explored, and all pseudarthroses were redecorticated and grafted with no graft, autograft, or OP-1. At 10 weeks, the rabbits were killed and fusions masses were assessed with manual palpation, radiography, computed tomography, and/or histology., Results: Nine rabbits (20%) were lost to complications. Thirty-four (94%) had pseudarthroses on exploration at 5 weeks. By manual palpation at 10 weeks, 1 of 10 (10%) pseudarthroses that received no graft fused, 5 of 12 (42%) pseudarthroses that received autograft fused, and 9 of 11 (82%) pseudarthroses that received OP-1 fused. Computed tomography and histology further characterized the fusion masses., Conclusions: This study establishes a model for treatment of pseudarthroses. OP-1, which has previously been shown to have 100% fusion rate in animal models, outperformed autograft and induced fusion in 82% of rabbits.

The radiographs of 35 consecutive adult patients with isthmic spondylolisthesis who underwent a transforaminal lumbar interbody fusion (TLIF) with one or two Brantigan carbon fiber cages and pedicle screw instrumentation were evaluated. Anterolisthesis, disk space height, and slip angle were measured in preoperative and postoperative standing neutral radiographs. Anterolisthesis was reduced and disk space height was increased with the TLIF procedure. Average slip angle, however, was not significantly altered. The restoration of lordosis across the listhetic disk space correlated with a more anterior placement of the interbody cage within the disk space. The TLIF technique, performed with the Brantigan cage and pedicle screw instrumentation, appears to be able to restore disk height and reduce forward translation in patients with isthmic spondylolisthesis, but improvement in sagittal alignment is dependent upon anterior placement of the interbody device.

Bone grafting to achieve fusion is frequently performed in spinal surgery. Autograft is the gold standard bone graft material. However, due to limitations of supply and morbidity associated with the harvest of autograft, alternatives are being considered. Osteoconductive matrices, such as allograft, calcium or ceramic preparations are one such class of potential bone graft alternatives, but generally they lack osteoinductive properties. Recent attention has focused on osteoinductive materials such as demineralised bone matrix, recombinant bone morphogenetic proteins and bone marrow aspirates or blood product concentrates. These products may be combined with osteoconductive carriers and are clearly finding a place in the clinical arena.

Background Context: There are three phases in prophylaxis of surgical site infections (SSI): preoperative, intraoperative and postoperative. There is lack of consensus and paucity of evidence with SSI prophylaxis in the postoperative period.Purpose: To systematically evaluate the literature, and provide evidence-based summaries on postoperative measures for SSI prophylaxis in spine surgery.Study Design: Systematic review, meta-analysis, evidence synthesis.Methods: A systematic review conforming to PRIMSA guidelines was performed utilizing PubMed (MEDLINE), EMBASE, and the Cochrane Database from inception to January 2019. The GRADE approach was used for quality appraisal and synthesis of evidence. Six postoperative care domains with associated key questions were identified. Included studies were extracted into evidence tables, data synthesized quantitatively and qualitatively, and evidence appraised per GRADE approach.Results: Forty-one studies (nine RCT, 32 cohort studies) were included. In the setting of preincisional antimicrobial prophylaxis (AMP) administration, use of postoperative AMP for SSI reduction has not been found to reduce rate of SSI in lumbosacral spine surgery. Prolonged administration of AMP for more than 48 hours postoperatively does not seem to reduce the rate of SSI in decompression-only or lumbar spine fusion surgery. Utilization of wound drainage systems in lumbosacral spine and adolescent idiopathic scoliosis corrective surgery does not seem to alter the overall rate of SSI in spine surgery. Concomitant administration of AMP in the presence of a wound drain does not seem to reduce the overall rate of SSI, deep SSI, or superficial SSI in thoracolumbar fusion performed for degenerative and deformity spine pathologies, and in adolescent idiopathic scoliosis corrective surgery. Enhanced-recovery after surgery clinical pathways and infection-specific protocols do not seem to reduce rate of SSI in spine surgery. Insufficient evidence exists for other types of spine surgery not mentioned above, and also for non-AMP pharmacological measures, dressing type and duration, suture and staple management, and postoperative nutrition for SSI prophylaxis in spine surgery.Conclusions: Despite the postoperative period being key in SSI prophylaxis, the literature is sparse and without consensus on optimum postoperative care for SSI prevention in spine surgery. The current best evidence is presented with its limitations. High quality studies addressing high risk cohorts such as the elderly, obese, and diabetic populations, and for traumatic and oncological indications are urgently required. [ABSTRACT FROM AUTHOR]