Semitendinosus Tendon Augmentation for Prevention of Proximal Junctional Failure.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: The aim of this study was to compare the incidence of proximal junctional kyphosis (PJK), proximal junctional failure (PJF), and clinical outcomes of patients who did and did not receive posterior ligament complex (PLC) augmentation using a semitendinosus allograft when undergoing long-segment posterior spinal fusion for adult spinal deformity. SUMMARY OF BACKGROUND DATA: Clinical research on the augmentation of the PLC to prevent PJK and PJF has been limited to small case series without a comparable control group. METHODS: From 2014 to 2019, a consecutive series of patients with adult spinal deformity who underwent posterior long-segment spinal fusion with semitendinosus allograft to augment the PLC (allograft) or without PLC augmentation (control) were identified. Preoperative and postoperative spinopelvic parameters were measured. PJK, PJF, and Oswestry Disability Index (ODI) scores were recorded and compared between the two groups. Univariate and multivariate analysis was performed. P ≤ 0.05 was considered significant. RESULTS: Forty-nine patients in the allograft group and 34 patients in the control group were identified. There were no significant differences in demographic variables or operative characteristics between the allograft and control group. Preoperative and postoperative spinopelvic parameters were also similar between the two groups. PJK was present in 33% of patients in the allograft group and 32% of patients in the control group (P = 0.31). PJF did not occur in the allograft group, whereas six patients (18%) in the control group developed PJF (P = 0.01). Postoperative absolute ODI was significantly better in the allograft group (P = 0.007). CONCLUSION: The utilization of semitendinosus allograft tendon to augment the PLC at the upper instrumented vertebrae in patients undergoing long-segment posterior spinal fusion for adult deformity resulted in a significant decrease in PJF incidence and improved functional outcomes when compared to a cohort with similar risk of developing PJK and PJFLevel of Evidence: 3.

Use of a Reverse Bohlman Technique for Low-Grade Spondylolisthesis.

BACKGROUND: Treatment of spondylolisthesis can be difficult with regard to patients with high sacral slopes that may prohibit placement of interbody grafts for fusions across that segment. Here, we describe placement of a reverse Bohlman technique from an anterior approach to obtain fusion across a low-grade spondylolisthesis with a high sacral slope to obtain anterior fusion. METHODS: A chart review was conducted on this single patient regarding his clinical course and outcome. RESULTS: A 54-year-old male presented with low-back pain associated with bilateral leg pain dating back several years. Plain films demonstrated a Grade II isthmic spondylolisthesis at L5-S1 with spinopelvic measurements of 73° sacral slope, 82° lumbar lordosis, 12° pelvic tilt, and 94° pelvic incidence. Magnetic resonance imaging showed bilateral L5 pars defects with diffuse degenerative disease from L4 through S1 and significant ligamentous and facet hypertrophy. He underwent an L4-5 anterior lumbar interbody fusion and an L5-S1 reverse Bohlman placement of a transvertebral transsacral titanium mesh cage. This was supplemented with a posterior decompression and instrumentation from L4-ilium. He had resolution of his radiculopathy and has maintained a good clinical outcome at 3 years follow up. CONCLUSIONS: We present here a patient with low-grade spondylolisthesis and a steep sacral slope who underwent a successful reverse Bohlman approach with long-term follow up. This report highlights the potential utility of this method as a viable alternative for patients with low-grade spondylolisthesis. LEVEL OF EVIDENCE: IV. CLINICAL RELEVANCE: Technical description of surgical technique.

The DOWN Questionnaire: A Novel Screening Tool for Cervical Spondylotic Myelopathy.

STUDY DESIGN: Case-control study. OBJECTIVES: Cervical spondylotic myelopathy (CSM) is the most common cause of spinal cord injury in adults aged over 55 years. However, since the onset is typically insidious, accurately diagnosing CSM can be challenging, often requiring referral to a subspecialist and advanced imaging. To help identify patients at risk for CSM, this case-control study compared responses to a series of 4 questions (DOWN questionnaire) in myelopathic and non-myelopathic patients. METHODS: Ninety-two patients, 46 with and 46 without myelopathy, were recruited for the study. Each patient answered 4 questions encompassing common symptoms associated with CSM. Responses between patient groups were compared, and Cohen's κ was used to assess for agreement between responses and the diagnosis of myelopathy. RESULTS: We found a sensitivity of 91% and a κ of 0.54 to 3 positive responses and a sensitivity of 72% and a κ of 0.61 to 4 positive responses. CONCLUSIONS: Positive responses to 3 or more DOWN questions has high sensitivity and moderate agreement with the diagnosis of myelopathy based on history, physical exam, and review of advanced imaging by an orthopedic or neurological surgeon. The DOWN questionnaire is a potentially useful screening tool to identify patients at risk for CSM.

Frailty Syndrome and the Use of Frailty Indices as a Preoperative Risk Stratification Tool in Spine Surgery: A Review.

This comprehensive narrative literature review aims to extract studies related to frailty indices and their use in elective spine procedures, as limited studies regarding frailty exist in the spine literature. Most studies are retrospective analyses of prospectively collected databases. Evidence suggests a positive correlation between frailty level and mortality rate, postoperative complication rate, length of stay, and the possibility of discharge to a skilled nursing facility; these correlations have been illustrated across various spine procedures. The leading index is the modified frailty index, which measures 11 deficits. The development of more comprehensive frailty indices, such as the Adult Spinal Deformity Frailty Index, are promising and have high predictive value regarding postoperative complication rate in patients with spinal deformity. However, a frailty index that combines clinical, radiographic, and laboratory measures awaits development. Perhaps, the use of a frailty index in preoperative risk stratification for elective spine procedures could serve multiple purposes, including screening for high-risk patients, enhancement of operative decision making, approximation of complication rate for informed decision making, and refinement of perioperative care. Further prospective studies are warranted to determine clinically meaningful interventions in frail individuals.

Addition of Intrathecal Morphine for Postoperative Pain Management in Pediatric Spine Surgery: A Meta-analysis.

STUDY DESIGN: Meta-analysis. OBJECTIVE: The objective of this study was to determine whether adjunctive intrathecal morphine (ITM) reduces postoperative analgesic consumption following pediatric spine surgery. SUMMARY OF BACKGROUND DATA: Previous studies that have tested supplemental ITM to manage pain after pediatric spine surgery have been limited by small sample sizes. METHODS: A comprehensive search of PubMed, Web of Science, Clinicaltrials.gov, and the Cochrane Central Register of Controlled Trials was performed for clinical trials and observational studies. Time to first analgesic demand, postoperative analgesic use, pain scores, and complication data were abstracted from each study. Mean difference (MD) and 95% confidence interval (CI) were used to compare continuous outcomes and odds ratios (OR) and 95% CI were used for dichotomous outcomes. RESULTS: A total of 5 studies, including 3 randomized controlled trials and 2 retrospective chart reviews, containing 636 subjects, were incorporated into meta-analysis. Subjects that were administered ITM in addition to postoperative analgesics (ITM group) were compared with those receiving postoperative analgesics only (control group). In the ITM group, time to first analgesic demand was longer (MD, 8.79; 95% CI, 4.20-13.37; P<0.001), cumulative analgesic consumption was reduced at 24 hours (MD, -0.40; 95% CI, -0.56 to -0.24; P<0.001), and cumulative analgesic consumption was reduced at 48 hours (MD, -0.43; 95% CI, -0.59 to -0.27; P<0.001). Neither postoperative pain scores at 24 hours (P=0.16) nor 48 hours (P=0.18) were significantly different between ITM and control groups. Rates of respiratory depression, nausea, vomiting, and pruritus were not different between groups (all Ps>0.05). CONCLUSIONS: Addition of ITM in pediatric spine surgery produced a potent analgesic effect in the immediate postoperative period. Patients administered ITM did not request opiates as early as control and consumed fewer opiates by the second postoperative day. Furthermore, use of ITM did not increase complications such as respiratory depression, nausea, vomiting, or pruritus.

Attitudes of Spine Surgeons Regarding Management of Preoperative Anxiety: A Cross-sectional Study.

STUDY DESIGN: This is a cross-sectional study. OBJECTIVE: To investigate spine surgeons' attitudes regarding preoperative anxiety measurement, management, and responsibility. SUMMARY OF BACKGROUND DATA: The vast majority of patients scheduled for spine surgery experience preoperative anxiety. However, there are currently no consensus guidelines for measure or management of preoperative anxiety in spinal operations. MATERIALS AND METHODS: An anonymous questionnaire was sent online to spine surgeons of AO Spine North America to capture their views regarding preoperative anxiety. RESULTS: Of 69 complete responses, most respondents were male (n=66, 95.7%), orthopedic surgeons (n=52, 75.4%), and practicing at an academic setting (n=39, 56.5%). Most spine surgeons practiced for at least 20 years (n=52, 75.4%), operated on 100-300 patients per year (n=48, 69.6%), and were attending physicians (n=61, 88.4%). Most did not measure preoperative anxiety (n=46, 66.7%) and would not use a rating scale to measure it (n=38, 55.1%). However, most would discuss it if mentioned by the patient (n=40, 58.0%). Other spine surgeons measured anxiety verbally (n=22, 31.9%) or with a rating scale or survey (n=6, 8.7%). Although preferences for preoperative anxiety management varied, most respondents used patient education (n=54, 78.3%) and permitting family members' presence (n=36, 52.2%) to reduce patient anxieties. Spine surgeons held themselves, anesthesiologists, and patients most responsible to manage preoperative anxiety. CONCLUSIONS: The majority of spine surgeons surveyed did not regularly measure preoperative anxiety, but would discuss its management if the subject was broached by the patient. Spine surgeons relied on a variety of methods to manage a patient's anxiety, but most preferred preoperative education and permitting the presence of family members. Responsibility for controlling preoperative anxiety was chiefly allocated to surgeons, anesthesiologists, and patients. Future avenues for research may include developing a preoperative anxiety measurement scale and management protocol specific to spine surgery. LEVEL OF EVIDENCE: Level IV.

Complications associated with intrathecal morphine in spine surgery: a retrospective study.

BACKGROUND: Supplemental intrathecal morphine (ITM) represents an option to manage postoperative pain after spine surgery due to ease of administration and ability to confer effective short-term analgesia at low dosages. However, whether ITM increases risk of surgical site infections (SSI), cerebrospinal fluid (CSF) leak, and incidental dural tears (IDT) has not been investigated. Therefore, this study was performed to determine the rates of SSI, CSF leak, and IDT in patients that received ITM. METHODS: Patients that underwent posterior instrumented fusion from January 2010 to 2016 that received ITM were compared to controls with respect to demographic, medical, surgical, and outcome data. Fisher's exact test was used to compare rates of SSI, CSF leak, and IDT between groups. Poisson regression was used to analyze complication rates after adjusting for the influence of covariates and potential confounders. RESULTS: A total of 512 records were analyzed. ITM was administered to 78 patients prior to wound closure. The remaining 434 patients compromised the control group. IDT was significantly more common among patients receiving ITM (P=0.009). Differences in rates of CSF leak and SSI were not statistically significant (P=0.373 and P=0.564, respectively). After compensating for additional variables, Poisson regression revealed a significant increase in rates of IDT (P=0.007) according to ITM injection and advanced age (P=0.014). There was no significant difference in rates of CSF leak or SSI after accounting for the additional variables (P>0.05). CONCLUSIONS: ITM for pain control in posterior instrumented spinal fusion surgery was linked to increased likelihood of IDT but not CSF leaks or SSI. Age was also noted to be a significant predictor of IDT. Spine surgeons should weigh potential risks against benefits when deciding whether to administer ITM for postoperative pain management following spine surgery.

Preferences of Spine Surgeons With Regard to Management of Intraoperative Durotomy: A Survey of Current Management.

STUDY DESIGN: This was a cross-sectional study. OBJECTIVE: The objective of this study was to determine spine surgeons' preferences for the intraoperative and postoperative management of intraoperative durotomy (IDT) in decompression and spinal fusion surgeries. SUMMARY OF BACKGROUND DATA: Management guidelines for IDT remain elusive. Traditionally, management consists of intraoperative suturing and postoperative bed rest. However, preferences of North American spine surgeons may vary, particularly according to type of surgery. MATERIALS AND METHODS: Spine surgeons of AO Spine North America (AOSNA) were surveyed online anonymously to determine which techniques they preferred to manage IDT in decompression and fusion. Differences in preferences according to surgery type were compared using the Fisher exact test. A series of linear regressions were conducted to identify demographic predictors of spine surgeons' preferences. RESULTS: Of 217 respondents, most were male (95%), orthopedic surgeons (70%), practiced at an academic center (50%), were in practice 0-19 years (71%) and operated on 100-300 patients per year (70%). The majority of surgeons applied sutures (93%-96%) and sealant (82%-84%). Surgeons also used grafts (26%-27%), drains (18%), other techniques (4%-5%), blood patch (2%-3%), or no intraoperative management (1%-2%). Postoperatively, most surgeons recommended bed rest (74%-75%). Antibiotics (22%), immediate mobilization (18%-20%), reoperation (14%-16%), other techniques (6%), or no postoperative management (5%) were also preferred. Management preferences did not vary significantly between decompression and fusion surgeries (all P-values>0.05). Specialty, practice facility, years in practice, and patients per year were identified as independent predictors of IDT management preferences (P<0.05). CONCLUSIONS: Although North American spine surgeons preferred to manage IDT with sutures augmented by sealant followed by bed rest after surgery, less common techniques were also preferred during the intraoperative and postoperative periods. Notably, intraoperative and postoperative IDT management preferences did not change in accordance to the type of surgery being conducted. LEVEL OF EVIDENCE: Level V.

An in Vitro Biomechanical Model of Differing Pedicle Screw Configurations for Long Construct Segmental Thoracic Fixation.

BACKGROUND: The optimum pattern of pedicle screw (PS) fixation during long-segment thoracic fixation has not been determined. OBJECTIVE: To evaluate rod stress and construct stability with minimal, alternating, skipped, and bilateral PS constructs in the iatrogenically destabilized thoracic spine. METHODS: Eight cadaveric thoracic specimens (T3-T12) were initially tested intact to ±5 Nm using a custom 6 degree-of-freedom spine testing apparatus in flexion-extension (FE), lateral bending (LB), and axial rotation. Specimens were instrumented with T4-T10 bilateral PS, with Ponte osteotomies to introduce instability. Rods were bent to fit the PS and then spines were tested with the minimal, alternating, skipped, and bilateral fixation patterns. Range of motion (ROM) was calculated from T4-T10 and segmentally. In addition, strain gauges fixed to the spinal rods measured rod stress under FE and LB. Results were compared using ANOVA and post hoc Holm Sidak tests. RESULTS: All fixation patterns provided significant reductions in ROM with respect to the intact spine. In all motion planes, minimal provided the least amount of rigidity, while bilateral provide the greatest; however, no statistically significant differences were detected in FE. In LB and axial rotation, skipped, alternating, and bilateral were all significantly more rigid than minimal (P < .01). Rod strains were greatest under LB and correlated with overall construct ROM, where bilateral had significantly lower strain than the other patterns (P < .05). CONCLUSION: All constructs effectively decreased thoracic ROM. There was significant improvement in stabilization and decreased rod stress when more fixation points beyond the minimal construct were included.

A Novel Lumbar Motion Segment Classification to Predict Changes in Segmental Sagittal Alignment After Lateral Interbody Fixation.

STUDY DESIGN: Retrospective cohort study. OBJECTIVES: Lateral interbody fixation is being increasingly used for the correction of segmental sagittal parameters. One factor that affects postoperative correction is the resistance afforded by posterior hypertrophic facet joints in the degenerative lumbar spine. In this article, we describe a novel preoperative motion segment classification system to predict postoperative correction of segmental sagittal alignment after lateral lumbar interbody fusion. METHODS: Preoperative computed tomography scans were analyzed for segmental facet osseous anatomy for all patients undergoing lateral lumbar interbody fusion at 3 institutions. Each facet was assigned a facet grade (min = 0, max = 2), and the sum of the bilateral facet grades was the final motion segment grade (MSG; min = 0, max = 4). Preoperative and postoperative segmental lordosis was measured on standing lateral radiographs. Postoperative segmental lordosis was also conveyed as a percentage of the implanted graft lordosis (%GL). Simple linear regression was conducted to predict the postoperative segmental %GL according to MSG. RESULTS: A total of 36 patients with 59 operated levels were identified. There were 19 levels with MSG 0, 14 levels with MSG 1, 13 levels with MSG 2, 8 levels with MSG 3, and 5 levels with MSG 4. Mean %GL was 115%, 90%, 77%, 43%, and 5% for MSG 0 to 4, respectively. MSG significantly predicted postoperative %GL (P < .01). Each increase in MSG was associated with a 28% decrease in %GL. CONCLUSIONS: We propose a novel facet-based motion segment classification system that significantly predicted postoperative segmental lordosis after lateral lumbar interbody fusion.

Transpedicular Corpectomy and Cage Placement in the Treatment of Traumatic Lumbar Burst Fractures.

STUDY DESIGN: Retrospective review. OBJECTIVE: To review the feasibility of a posterior-only approach for instrumented reconstruction in lumbar burst fractures. BACKGROUND: Burst fractures of the lumbar spine have been treated through a variety of techniques, including anterior, posterior, or combined approaches. Here we review series of patients undergoing posterior-only transpedicular corpectomy with instrumented fusion for traumatic lumbar burst fracture. METHODS: All patients treated at the Los Angeles County+University of Southern California (LAC+USC) Medical Center who had sustained traumatic lumbar burst fractures from February 2005 to February 2014 were reviewed. RESULTS: A total of 178 traumatic lumbar burst fractures were identified of which 89 required operative intervention. Of those 89 operations, 7 patients underwent posterior-only approach for transpedicular corpectomy. Levels operated on were at L1 (4 patients), L2 (1 patient), and L4 (2 patients). The mean age was 35 years of age (range, 21-56 y), and mechanism of injury was either motor vehicle accident (5 patients) or fall (2 patients). Initial neurological examination was American Spinal Injury Association (ASIA) B in 3 patients, ASIA D in 3 patients, and 1 patient was neurologically intact. Mean thoracolumbar injury classification and severity score on presentation was 6.4 (range, 5-8), whereas the mean load sharing classification score was 7.4 (range, 7-9). Of patients who were not immediately lost to follow-up on hospital discharge, mean clinical follow-up was 45.3 months (range, 18.8-68.6 mo), whereas mean radiographic follow-up was 28.8 months (range, 1.3-63.6 mo). At the last known radiographic follow-up, no patient had gross hardware fracture, pseudoarthrosis, or adjacent segment disease. One patient with the longest radiographic follow-up of 63.6 months was noted to have some minimal subsidence of his cage with no other change in his other hardware. CONCLUSION: A posterior-only approach for transpedicular corpectomy and instrumented fusion is a viable treatment option for lumbar burst fracture which allows for reconstruction of the anterior column while avoiding many of the risks and complications associated with an anterior or combined approach.

The Clinical Correlations between Diabetes, Cigarette Smoking and Obesity on Intervertebral Degenerative Disc Disease of the Lumbar Spine.

STUDY DESIGN: Retrospective analysis of a nationwide private insurance database. Chi-square analysis and linear regression models were utilized for outcome measures. PURPOSE: The purpose of this study was to investigate any relationship between lumbar degenerative disc disease, diabetes, obesity and smoking tobacco. OVERVIEW OF LITERATURE: Diabetes, obesity, and smoking tobacco are comorbid conditions known to individually have effect on degenerative disc disease. Most studies have only been on a small populous scale. No study has yet to investigate the combination of these conditions within a large patient cohort nor have they reviewed the combination of these conditions on degenerative disc disease. METHODS: A retrospective analysis of insurance billing codes within the nationwide Humana insurance database was performed, using PearlDiver software (PearlDiver, Inc., Fort Wayne, IN, USA), to identify trends among patients diagnosed with lumbar disc degenerative disease with and without the associated comorbidities of obesity, diabetes, and/or smoking tobacco. Patients billed for a comorbidity diagnosis on the same patient record as the lumbar disc degenerative disease diagnosis were compared over time to patients billed for lumbar disc degenerative disease without a comorbidity. There were no sources of funding for this manuscript and no conflicts of interest. RESULTS: The total number and prevalence of patients (per 10,000) within the database diagnosed with lumbar disc degenerative disease increased by 241.4% and 130.3%, respectively. The subsets of patients within this population who were concurrently diagnosed with either obesity, diabetes, tobacco use, or a combination thereof, was significantly higher than patients diagnosed with lumbar disc degenerative disease alone (p <0.05 for all). The number of patients diagnosed with lumbar disc degenerative disease and smoking rose significantly more than patients diagnosed with lumbar disc degenerative disease and either diabetes or obesity (p <0.05). The number of patients diagnosed with lumbar disc degenerative disease, smoking and obesity rose significantly more than the number of patients diagnosed with lumbar disc degenerative disease and any other comorbidity alone or combination of comorbidities (p <0.05). CONCLUSIONS: Diabetes, obesity and cigarette smoking each are significantly associated with an increased diagnosis of lumbar degenerative disc disease. The combination of smoking and obesity had a synergistic effect on increased rates of lumbar degenerative disc disease. Patient education and preventative care is a vital goal in prevention of degenerative disc disease within the general population.

Bisphosphonate's and Intermittent Parathyroid Hormone's Effect on Human Spinal Fusion: A Systematic Review of the Literature.

There has been a conscious effort to address osteoporosis in the aging population. As bisphosphonate and intermittent parathyroid hormone (PTH) therapy become more widely prescribed to treat osteoporosis, it is important to understand their effects on other physiologic processes, particularly the impact on spinal fusion. Despite early animal model studies and more recent clinical studies, the impact of these medications on spinal fusion is not fully understood. Previous animal studies suggest that bisphosphonate therapy resulted in inhibition of fusion mass with impeded maturity and an unknown effect on biomechanical strength. Prior animal studies demonstrate an improved fusion rate and fusion mass microstructure with the use of intermittent PTH. The purpose of this study was to determine if bisphosphonates and intermittent PTH treatment have impact on human spinal fusion. A systematic review of the literature published between 1980 and 2015 was conducted using major electronic databases. Studies reporting outcomes of human subjects undergoing 1, 2, or 3-level spinal fusion while receiving bisphosphonates and/or intermittent PTH treatment were included. The results of relevant human studies were analyzed for consensus on the effects of these medications in regards to spinal fusion. There were nine human studies evaluating the impact of these medications on spinal fusion. Improved fusion rates were noted in patients receiving bisphosphonates compared to control groups, and greater fusion rates in patients receiving PTH compared to control groups. Prior studies involving animal models found an improved fusion rate and fusion mass microstructure with the use of intermittent PTH. No significant complications were demonstrated in any study included in the analysis. Bisphosphonate use in humans may not be a deterrent to spinal fusion. Intermittent parathyroid use has shown early promise to increase fusion mass in both animal and human studies but further studies are needed to support routine use.

Intrathecal Morphine in Spine Surgery: A Meta-analysis of Randomized Controlled Trials.

STUDY DESIGN: Meta-analysis of randomized controlled trials (RCTs). OBJECTIVE: The aim of this study was to evaluate the effectiveness of intrathecal morphine (ITM) in reducing postoperative pain and opioid analgesic consumption following spine surgery. SUMMARY OF BACKGROUND DATA: The use of ITM following adult spine surgery is of particular interest because of the ease of access to the thecal sac and the potential to provide adequate analgesia at low doses. However, previous studies of ITM have been limited by small sample sizes and conflicting results. METHODS: A comprehensive search of PubMed, Web of Science, Clinicaltrials.gov, and the Cochrane Central Register of Controlled Trials for prospective RCTs was performed by two independent reviewers. Postoperative opioid consumption, pain scores, and complications were documented from the identified studies. Standard mean differences (SMDs) were applied to continuous outcomes and odds ratios were determined for dichotomous outcomes. RESULTS: Eight RCTs involving 393 subjects met inclusion criteria and were included in this meta-analysis. Patients receiving ITM (ITM group) as an adjunct to postoperative opioid analgesic were compared to patients receiving postoperative opioids only (control group). Postoperative morphine equivalent consumption was significantly lower during the first 24 hours postoperative in the ITM group (P < 0.001). Pain scores were similarly lower in the first 24 hours following spine surgery in those who received ITM (P < 0.001). In patients administered ITM, a greater percentage experienced pruritus (P < 0.001). Respiratory depression was solely encountered in the ITM group (P = 0.25). There were no significant differences between the ITM and control groups in terms of sedation (P = 0.18), nausea (P = 0.67), vomiting (P = 0.62), or length of stay (P = 0.13). CONCLUSION: In patients undergoing spine surgery, use of ITM significantly reduced opioid analgesic consumption and Visual Analogue Schores pain scores compared to controls within the first 24 hours postoperatively. High-quality, follow-up RCTs with large sample sizes are recommended to determine the potential of supplementary ITM in spine surgery and complete the side effects profile. LEVEL OF EVIDENCE: 1.

Bow Hunter's Syndrome: Surgical Management (Video) and Review of the Literature.

BACKGROUND: Bow Hunter's syndrome (BHS) is a rare condition characterized by vertebrobasilar insufficiency associated with rotational vertebral artery occlusion during head movement. Many existing reports describe surgical management, although no single technique has proven superior. OBJECTIVE: To review all reported cases of BHS with focus on outcomes of individual techniques as well as to present a video report of a posterior decompression without fusion performed at the authors' institution. METHODS: We searched PubMed for all relevant articles of BHS available in the English language. Pertinent studies were further characterized into surgical technique performed and associated outcomes. RESULTS: We included 27 studies in our review, excluding the case presented, for a total of 65 cases of BHS. These cases discuss anterior versus posterior decompressions, the need for fusion, coil embolization techniques, the efficacy of intraoperative dynamic angiography, and success rate with symptom resolution being the primary endpoint. A total of 53 cases underwent decompression without fusion, with an overall success rate of 90.6% (n = 48/53). Similarly, eleven cases underwent decompression with fusion, with a success rate of 91% (n = 10/11). Two additional cases opted for coil embolization, one of which reported resolution of symptoms. Furthermore, we present a video case of a posterior decompression without fusion with resolution of symptoms. CONCLUSIONS: BHS remains a rare clinical condition with no clear superior method of treatment. Rates of symptom resolution are similar among cases undergoing decompression with or without fusion. Coil embolization has been reported with limited success in 2 cases.

The use of a novel perfusion-based cadaveric simulation model with cerebrospinal fluid reconstitution comparing dural repair techniques: a pilot study.

BACKGROUND CONTEXT: Watertight dural repair is crucial for both incidental durotomy and closure after intradural surgery. PURPOSE: The study aimed to describe a perfusion-based cadaveric simulation model with cerebrospinal fluid (CSF) reconstitution and to compare spine dural repair techniques. STUDY DESIGN/SETTING: The study is set in a fresh tissue dissection laboratory. SAMPLE SIZE: The sample includes eight fresh human cadavers. OUTCOME MEASURES: A watertight closure was achieved when pressurized saline up to 40 mm Hg did not cause further CSF leakage beyond the suture lines. METHODS: Fresh human cadaveric specimens underwent cannulation of the intradural cervical spine for intrathecal reconstitution of the CSF system. The cervicothoracic dura was then exposed from C7-T12 via laminectomy. The entire dura was then opened in six cadavers (ALLSPINE) and closed with 6-0 Prolene (n=3) or 4-0 Nurolon (n=3), and pressurized with saline via a perfusion system to 60 mm Hg to check for leakage. In two cadavers (INCISION), six separate 2-cm incisions were made and closed with either 6-0 Prolene or 4-0 Nurolon, and then pressurized. A hydrogel sealant was then added and the closure was pressurized again to check for further leakage. RESULTS: Spinal laminectomy with repair of intentional durotomy was successfully performed in eight cadavers. The operative microscope was used in all cases, and the model provided a realistic experience of spinal durotomy repair. For ALLSPINE cadavers (mean: 240 mm dura/cadaver repaired), the mean pressure threshold for CSF leakage was observed at 66.7 (±2.9) mm Hg in the 6-0 Prolene group and at 43.3 (±14.4) mm Hg in the 4-0 Nurolon group (p>.05). For INCISION cadavers, the mean pressure threshold for CSF leakage without hydrogel sealant was significantly higher in 6-0 Prolene group than in the 4-0 Nurolon group (6-0 Prolene: 80.0±4.5 mm Hg vs. 4-0 Nurolon: 32.5±2.7 mm Hg; p<.01). The mean pressure threshold for CSF leakage with the hydrogel sealants was not significantly different (6-0 Prolene: 100.0±0.0 mm Hg vs. 4-0 Nurolon: 70.0±33.1 mm Hg). The use of a hydrogel sealant significantly increased the pressure thresholds for possible CSF leakage in both the 6-0 Prolene group (p=.01) and the 4-0 Nurolon group (p<.01) when compared with mean pressures without the hydrogel sealant. CONCLUSIONS: We described the feasibility of using a novel cadaveric model for both the study and training of watertight dural closure techniques. 6-0 Prolene was observed to be superior to 4-0 Nurolon for watertight dural closure without a hydrogel sealant. The use of a hydrogel sealant significantly improved watertight dural closures for both 6-0 Prolene and 4-0 Nurolon groups in the cadaveric model.

Biomechanical analysis of lateral interbody fusion strategies for adjacent segment degeneration in the lumbar spine.

BACKGROUND CONTEXT: Surgical treatment of symptomatic adjacent segment disease (ASD) typically involves extension of previous instrumentation to include the newly affected level(s). Disruption of the incision site can present challenges and increases the risk of complication. Lateral-based interbody fusion techniques may provide a viable surgical alternative that avoids these risks. This study is the first to analyze the biomechanical effect of adding a lateral-based construct to an existing fusion. PURPOSE: The study aimed to determine whether a minimally invasive lateral interbody device, with and without supplemental instrumentation, can effectively stabilize the rostral segment adjacent to a two-level fusion when compared with a traditional posterior revision approach. STUDY DESIGN/SETTING: This is a cadaveric biomechanical study of lateral-based interbody strategies as add-on techniques to an existing fusion for the treatment of ASD. METHODS: Twelve lumbosacral specimens were non-destructively loaded in flexion, extension, lateral bending, and torsion. Sequentially, the tested conditions were intact, two-level transforaminal lumbar interbody fusion (TLIF) (L3-L5), followed by lateral lumbar interbody fusion procedures at L2-L3 including interbody alone, a supplemental lateral plate, a supplemental spinous process plate, and then either cortical screw or pedicle screw fixation. A three-level TLIF was the final instrumented condition. In all conditions, three-dimensional kinematics were tracked and range of motion (ROM) was calculated for comparisons. Institutional funds (<$50,000) in support of this work were provided by Medtronic Spine. RESULTS: The addition of a lateral interbody device superadjacent to a two-level fusion significantly reduced motion in flexion, extension, and lateral bending (p<.05). Supplementing with a lateral plate further reduced ROM during lateral bending and torsion, whereas a spinous process plate further reduced ROM during flexion and extension. The addition of posterior cortical screws provided the most stable lateral lumbar interbody fusion construct, demonstrating ROM comparable with a traditional three-level TLIF. CONCLUSIONS: The data presented suggest that a lateral-based interbody fusion supplemented with additional minimally invasive instrumentation may provide comparable stability with a traditional posterior revision approach without removal of the existing two-level rod in an ASD revision scenario.

A Portable Shoulder-Mounted Camera System for Surgical Education in Spine Surgery.

The past several years have demonstrated an increased recognition of operative videos as an important adjunct for resident education. Currently lacking, however, are effective methods to record video for the purposes of illustrating the techniques of minimally invasive (MIS) and complex spine surgery. We describe here our experiences developing and using a shoulder-mounted camera system for recording surgical video. Our requirements for an effective camera system included wireless portability to allow for movement around the operating room, camera mount location for comfort and loupes/headlight usage, battery life for long operative days, and sterile control of on/off recording. With this in mind, we created a shoulder-mounted camera system utilizing a GoPro™ HERO3+, its Smart Remote (GoPro, Inc., San Mateo, California), a high-capacity external battery pack, and a commercially available shoulder-mount harness. This shoulder-mounted system was more comfortable to wear for long periods of time in comparison to existing head-mounted and loupe-mounted systems. Without requiring any wired connections, the surgeon was free to move around the room as needed. Over the past several years, we have recorded numerous MIS and complex spine surgeries for the purposes of surgical video creation for resident education. Surgical videos serve as a platform to distribute important operative nuances in rich multimedia. Effective and practical camera system setups are needed to encourage the continued creation of videos to illustrate the surgical maneuvers in minimally invasive and complex spinal surgery. We describe here a novel portable shoulder-mounted camera system setup specifically designed to be worn and used for long periods of time in the operating room.

Low-magnitude mechanical signals and the spine: A review of current and future applications.

Animal and human studies demonstrate the anabolic properties of low-magnitude mechanical stimulation (LMMS) in its ability to improve bone formation by enhancing the proliferation of mesenchymal stem cells and their subsequent commitment down an osteoblastic lineage. Response to mechanical strains as low as 10µÉ› have been seen, illustrating the sensitivity of mechanosensory cells to mechanotransduction pathways. Applications to the spine include treatment of osteoporosis in preparation for instrumented fusion, fracture reduction in spinal cord injury patients to slow bone mineral density loss, and bone tissue engineering and enhancement of bone-implant osseointegration for pseudarthrosis and hardware failure. This review provides an overview of the fundamentals of LMMS, highlights the cellular basis and biomechanics of how mechanical strain is translated into bone formation, and then discusses current and potential applications of these concepts to spinal disorders. Mechanical signals represent a key regulatory mechanism in the maintenance and formation of bone. Developing practical clinical applications of these mechanotransduction pathways continues to be an important area of investigation in its relation to spinal pathology.

Semitendinosus Graft for Interspinous Ligament Reinforcement in Adult Spinal Deformity.

Proximal junctional kyphosis is an increasingly recognized complication following long-segment posterior spinal fusion for adult spinal deformity. The authors describe a novel technique for interspinous ligament reinforcement at the proximal adjacent levels using a cadaveric semitendinosus tendon graft secured with an Ethibond No. 2 double filament (Ethicon, Somerville, New Jersey) via the Krackow suture weave. A retrospective review identified 4 patients who had received this graft. No proximal junctional kyphosis was seen at a mean short-term follow-up of 5.5 months. Interspinous ligament reinforcement at the proximal adjacent level with a cadaveric semitendinosus tendon graft is a feasible strategy for preventing proximal junctional kyphosis. [Orthopedics. 2017; 40(1):e206-e210.].