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Background and Objectives: Awake minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) generates minimal surrounding tissue damage and has been shown to be a safe, time-effective, and cost-reductive technique in single-level procedures. The purpose of this study was to advocate for the utilization of multilevel MIS-TLIF even in challenging cases as it has demonstrated positive outcomes., Methods: Chart review was conducted for consecutive patients undergoing awake multilevel MIS-TLIF from 2020 to 2023. Various demographic, preoperative, and postoperative variables were collected and descriptively analyzed., Results: Sixteen patients underwent multilevel awake MIS-TLIF at our institution during the specified period. Among them, 87.5% underwent a two-level procedure and 12.5% a three-level procedure. The median age ± IQR was 69.5 ± 11 years, with a slight male predominance (56.25%). Common comorbidities included hypertension (56.25%), obesity (37.5%), sleep apnea (25%), and type 2 diabetes (18.75%). The American Society of Anesthesiologists risk was 2 in 43.75% of patients and 3 in 56.25%. All patients presented pain, and 12.5% showed motor deficit. Intraoperative data showed a median of 196 minutes in the operating room where 156 ± 27.75 minutes corresponded to actual procedure time. The median estimated blood loss was 50 ± 70 cc. In the immediate postoperative period, 1 patient had nausea and emesis, and 1 reported fatigue. The median pain score during this period was 4.6 ± 2.03. Pain control medications were required for various patients, with methocarbamol (50%), hydromorphone (37.5%), and oxycodone (25%) being the most commonly prescribed in the postanesthesia care unit. No patient had new neurological deficits after the surgical intervention. The median length of stay was 2 days ±1.25. All patients were discharged with no complications., Conclusion: Multilevel awake MIS-TLIF emerges as a safe and effective technique for complex cases, enhancing patient quality of life with minimal blood loss and postoperative pain., (Copyright © Congress of Neurological Surgeons 2024. All rights reserved.)

Objective: Low- and middle-income countries (LMICs) face many challenges compared to industrialized nations, most notably in regard to the health care system. Patients often have to travel long distances to receive medical care with few reliable transportation mechanisms. In time-critical emergencies, this is a significant disadvantage. One specialty that is particularly affected by this is spine surgery. Within this field, traumatic injuries and acutely compressive pathologies are often time-critical. Increasing global networking capabilities through internet access offers the possibility for telemedical support in remote regions. Recently, high-performance cameras and processors became available in commercially available smartphones. Due to their wide availability and ease of use, this could provide a unique opportunity to offer telemedical support in LMICs. Methods: We conducted a feasibility study with a neurosurgical institution in east Africa. To ensure telemedical support, a commercially available smartphone was selected as the experimental hardware. Preoperatively, resolution, contrast, brightness, and color reproduction were assessed under theoretical conditions using a test chart. Intraoperatively, the image quality was assessed under different conditions. In the first step, the instrumentation table was displayed, and the mentor surgeon marked an instrument that the mentee surgeon should recognize correctly. In the next evaluation step, the surgical field was shown on film and the mentor surgeon marked an anatomical structure, and in the last evaluation step, the screen of the X-ray machine was captured, and the mentor surgeon again marked an anatomical structure. Subjective image quality was rated by two independent reviewers using the similar modified Likert scale as before on a scale of 1-5, with 1 indicating inadequate quality and 5 indicating excellent quality. Results: The image quality during the video calls was rated as sufficient overall. When evaluating the test charts, a quality of 97% ± 5 on average was found for the chart with the white background and a quality of 84% ± 5 on average for the chart with the black background. The color reproduction, the contrast, and the reproduction of brightness were rated excellent. Intraoperatively, the visualization of the instrument table was also rated excellent. Visualization of the operative site was rated 1.5 ± 0.5 on average and it was not possible to recognize relevant anatomical structures with the required confidence for surgical procedures. Image quality of the X-ray screen was rated 1.5 ± 0.9 on average. Conclusion: Current generation smartphones have high imaging performance, high computing power, and excellent connectivity. However, relevant anatomical structures during spine surgery procedures and on the X-ray screen in the operating room could not be identified with reliability to provide adequate surgical support. Nevertheless, our study showed the potential in smartphones supporting surgical procedures in LMICs, which could be helpful in other surgical fields.

Background: Spine surgery is a rapidly evolving specialty with a continuous need to learn new skills. In resource-limited settings such as Africa, the need for training is greater. The use of simulation-based training is important in different stages of skill acquisition, especially for high-stake procedures such as spine surgery. Among the available methods of simulation, the use of synthetic models has gained popularity among trainers., Method: Twenty participants of a neurosurgery training course, most of whom (65%) were neurosurgery residents and fellows, were recruited. They had hands-on training sessions using a high-fidelity lumbar degenerative spine simulation model and hands-on theater experience. After this, they completed a survey to compare their experience and assess the effectiveness of the lumbar spine model in stimulating real patient and surgery experiences., Results: The participants were from four African countries, and the majority were neurosurgery residents. There were varying levels of experience among the participants in minimally invasive spine surgery, with the majority either having no experience or having only observed the procedure. All the participants said that the high-fidelity lumbar spine model effectively simulated real minimally invasive spine setup and real bone haptics and was effective in learning new techniques. Most of the participants agreed that the model effectively simulated real dura and nerve roots (95%), real muscle (90%), real bleeding from bones and muscles (95%), and real cerbrospinal fluid in the subarachnoid space. Among them, 95% agreed that the model is effective in lumbar minimally invasive spine training in resource-limited settings., Conclusion: With the development of new and better surgical techniques, the use of high-fidelity models provides a good opportunity for learning and training, especially in resource-poor settings where there is a paucity of training facilities and personnel., (Copyright © 2023 The Authors. Published by Wolters Kluwer Health, Inc. on behalf of the American Academy of Orthopaedic Surgeons.)

Background: Excess flexion or extension during occipitocervical fusion (OCF) can lead to postoperative complications, such as dysphagia, respiratory problems, line of sight issues, and neck pain, but posterior fossa decompression (PFD) and OCF require different positions that require intraoperative manipulation., Objective: The objective of this study was to describe quantitative fluoroscopic morphometrics in Chiari malformation (CM) patients with symptoms of craniocervical instability (CCI) and demonstrate the intraoperative application of these measurements to achieve neutral craniocervical alignment while leveraging a single axis of motion with the Mayfield head clamp locking mechanism., Methods: A retrospective cohort study of patients with CM 1 and 1.5 and features of CCI who underwent PFD and OCF at a single-center institution from March 2015 to October 2020 was performed. Patient demographics, preoperative presentation, radiographic morphometrics, operative details, complications, and clinical outcomes were analyzed., Results: A total of 39 patients met the inclusion criteria, of which 37 patients (94.9%) did not require additional revision surgery after PFD and OCF. In this nonrevision cohort, preoperative to postoperative occipital to C2 angle (O-C2a) (13.5 ° ± 10.4 ° vs. 17.5 ° ± 10.1 ° , P = 0.047) and narrowest oropharyngeal airway space (nPAS) (10.9 ± 3.4 mm vs. 13.1 ± 4.8 mm, P = 0.007) increased significantly. These measurements were decreased in the two patients who required revision surgery due to postoperative dysphagia (mean difference - 16.6 ° ° in O C2a and 12.8 ° ° in occipital and external acoustic meatus to axis angle). Based on these results, these fluoroscopic morphometrics are intraoperatively assessed, utilizing a locking Mayfield head clamp repositioning maneuver to optimize craniocervical alignment prior to rod placement from the occipital plate to cervical screws., Conclusion: Establishing a preoperative baseline of reliable fluoroscopic morphometrics can guide surgeons intraoperatively in appropriate patient realignment during combined PFD and OCF, and may prevent postoperative complications., Competing Interests: There are no conflicts of interest., (Copyright: © 2023 Journal of Craniovertebral Junction and Spine.)

Study Design: Prospective comparative study., Objective: To quantify the educational benefit to surgical trainees of using a high-fidelity simulator to perform minimally invasive (MIS) unilateral laminotomy for bilateral decompression (ULBD) for lumbar stenosis., Methods: Twelve orthopedic and neurologic surgery residents performed three MIS ULBD procedures over 2 weeks on a simulator guided by established AO Spine metrics. Video recording of each surgery was rated by three blinded, independent experts using a global rating scale. The learning curve was evaluated with attention to technical skills, skipped steps, occurrence of errors, and timing. A knowledge gap analysis evaluating participants' current vs desired ability was performed after each trial., Results: From trial 1 to 3, there was a decrease in average procedural time by 31.7 minutes. The cumulative number of skipped steps and surgical errors decreased from 25 to 6 and 24 to 6, respectively. Overall surgical proficiency improved as indicated by video rating of efficiency and smoothness of surgical maneuvers, most notably with knowledge and handling of instruments. The greatest changes were noted in junior rather than senior residents. Average knowledge gap analysis significantly decreased by 30% from the first to last trial (P = .001), signifying trainees performed closer to their desired technical goal., Conclusion: Procedural metrics for minimally invasive ULBD in combination with a realistic surgical simulator can be used to improve the skills and confidence of trainees. Surgical simulation may offer an important educational complement to traditional methods of skill acquisition and should be explored further with other MIS techniques.

Background: Low back pain is a global health problem directly related to intervertebral disc (IVD) degeneration. Senolytic drugs (RG-7112 and o-Vanillin) target and remove senescent cells from IVDs in vitro, improving tissue homeostasis. One drawback of using a single senolytic agent is the failure to target multiple senescent antiapoptotic pathways. This study aimed to determine if combining the two senolytic drugs, o-Vanillin and RG-7112, could more efficiently remove senescent cells and reduce the release of inflammatory factors and pain mediators in cells from degenerating human IVDs than either drug alone., Methods: Preliminary data evaluating multiple concentrations of o-Vanillin and RG-7112 led to the selection of four treatment groups. Monolayer and pellet cultures of cells from painful degenerate IVDs were exposed to TLR-2/6 agonist. They were then treated with the senolytics o-Vanillin and RG7112 alone or combined. p16 ink4a , Ki-67, caspase-3, inflammatory mediators, and neuronal sprouting were assessed., Results: Compared to the single treatments, the combination of o-Vanillin and RG-7112 significantly reduced the amount of senescent IVD cells, proinflammatory cytokines, and neurotrophic factors. Moreover, both single and combination treatments significantly reduced neuronal sprouting in rat adrenal pheochromocytoma (PC-12 cells)., Conclusions: Combining o-Vanillin and RG-7112 greatly enhanced the effect of either senolytic alone. Together, these results support the potential of senolytics as a promising treatment for IVD-related low back pain.

Introduction: Surgical decompression is standard care in the treatment of degenerative spondylolisthesis in patients with symptomatic lumbar spinal stenosis, but there remains controversy over the benefits of adding fusion. The persistent lack of consensus on this matter and the availability of new data warrants a contemporary systematic review and meta-analysis of the literature., Methods: Multiple online databases were systematically searched up to October 2022 for randomized controlled trials (RCTs) and prospective studies comparing outcomes of decompression alone versus decompression with fusion for lumbar spinal stenosis in patients with degenerative spondylolisthesis. Primary outcome was the Oswestry Disability Index. Secondary outcomes included leg and back pain, surgical outcomes, and radiological outcomes. Pooled effect estimates were calculated and presented as mean differences (MD) with their 95% confidence intervals (CI) at two-year follow-up., Results: Of the identified 2403 studies, eventually five RCTs and two prospective studies were included. Overall, most studies had a low or unclear risk of selection bias and most studies were focused on low grade degenerative spondylolisthesis. All patient-reported outcomes showed low statistical heterogeneity. Overall, there was high-quality evidence suggesting no difference in functionality at two years of follow-up (MD - 0.31, 95% CI - 3.81 to 3.19). Furthermore, there was high-quality evidence of no difference in leg pain (MD - 1.79, 95% CI - 5.08 to 1.50) or back pain (MD - 2.54, 95% CI - 6.76 to 1.67) between patients undergoing decompression vs. decompression with fusion. Pooled surgical outcomes showed less blood loss after decompression only, shorter length of hospital stay, and a similar reoperation rate compared to decompression with fusion., Conclusion: Based on the current literature, there is high-quality evidence of no difference in functionality after decompression alone compared to decompression with fusion in patients with degenerative lumbar spondylolisthesis at 2 years of follow-up. Further studies should focus on long-term comparative outcomes, health economic evaluations, and identifying those patients that may benefit more from decompression with fusion instead of decompression alone. This review was registered at Prospero (CRD42021291603)., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: Safe posterior cervical spine surgery requires in-depth understanding of the surgical anatomy and common variations. The cervical pedicle attachment site to the vertebral body (VB) affects the location of exiting nerve roots and warrants preoperative evaluation. The relative site of attachment of the cervical pedicle has not been previously described., Objective: To describe the site of the pedicle attachment to the VB in the subaxial cervical spine., Methods: Cervical spine computed tomography scans without any structural, degenerative, or traumatic pathology as read by a board-certified neuroradiologist during 2021 were reviewed. Multiplanar reconstructions were created and cross-registered. The pedicle's attachment to the VB was measured relative to the VB height using a novel calculation system., Results: Fifty computed tomography scans met inclusion criteria yielding 600 total pedicles between C3-T1 (100 per level). The average patient age was 26 ± 5.3 years, and 21/50 (42%) were female. 468/600 (78%) pedicles attached in the cranial third of the VB, 132/600 (22%) attached in the middle third, and 0 attached to the caudal third. The highest prevalence of variant anatomy occurred at C3 (36/100 C3 pedicles; 36%)., Conclusion: In the subaxial cervical spine, pedicles frequently attach to the top third of the VB, but significant variation is observed. The rate of variation is highest at C3 and decreases linearly with caudal progression down the subaxial cervical spine to T1. This is the first report investigating this morphological phenomenon., (Copyright © Congress of Neurological Surgeons 2022. All rights reserved.)

Background: Single-stage lateral lumbar interbody fusion is a safe and effective procedure that relies on indirect decompression and fusion to treat various lumbar pathologies. This technique, however, has an overall 9% rate of indirect decompression failure, which may require additional surgery to achieve adequate direct decompression. To address this concern, we modified this technique by adding a minimally invasive, direct tubular decompression in lateral position when indicated. No study has described the technical nuances of incorporating a microtubular decompression into the single-stage lateral lumbar interbody fusion workflow (SSLLIF+)., Objective: To report on the procedural steps and clinical outcomes of the SSLLIF+., Methods: In this retrospective case series of prospectively collected data, we present the detailed surgical approach of the SSLLIF+ with a single-center case series over a 5-year period. Surgical and clinical outcomes are presented., Results: A total of 7 patients underwent a SSLLIF+ with a total of 18 levels fused and 7 levels decompressed. The SSLLIF+ was successfully performed in all cases without the occurrence of intraoperative complications in this case series. There was 1 revision after 20 months of follow-up because of adjacent segment disease. There was no need for further direct decompression in a delayed fashion., Conclusion: SSLLIF with direct microtubular decompression in lateral position is a safe and effective procedure in patients where indirect decompression alone may not achieve the surgical goal. Adherence to minimally invasive spine surgery principles and thoughtful patient selection facilitate the successful management of these patients while demonstrating short hospital stay and low-risk of perioperative complications., (Copyright © Congress of Neurological Surgeons 2022. All rights reserved.)

Background Preoperative segmental instability maybe a predictor of postoperative outcomes when treated with lateral lumbar interbody fusion (LLIF). An abnormal collection of fluid within the facet joint has been described as a sign of segmental instability. The potential relationship between this radiological sign and its prognostic relevance for indirect decompression (ID) has not been investigated. Methods Clinical and radiologic results from patients undergoing LLIF in a single institution between 2007 and 2014 were evaluated retrospectively. Patients were divided into two groups: those presenting with excessive fluid (EF) in the facet joints on T2-MRI and those with a normal amount of facet fluid with less than 1mm, which were controls. Radiological parameters were foraminal height, disc height, Cobb angle, and lumbar lordosis. Results A total of 21 patients (43 operated levels) were evaluated pre- and postoperatively. Mean disc height, mean foraminal height, and coronal Cobb angles were statistically significantly improved after LLIF. Only the EF group showed significant improvement in radiological markers after ID; the mean disc height improved from 5.5±2 to 8.8±1mm (p=0.001), mean foraminal height improved from 16.88±3 to 20.53±3mm (p=0.002), and the mean Cobb angle improved from 27.7±16 to 14±13 (p=0.018). Conclusions Patients undergoing LLIF with the radiological findings of EF in the facet joints demonstrated significant improvement in radiological outcomes of ID. Further studies should validate these findings in larger data sets., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2022, Angel Roldan et al.)

Competing Interests: Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://atm.amegroups.com/article/view/10.21037/atm-22-3732/coif). The authors have no conflicts of interest to declare.

Objective: Surgical resection of benign intradural extramedullary tumors (BIETs) is effective for appropriately selected patients. Minimally invasive surgical (MIS) techniques have been described for successful resection of BIET while minimizing soft tissue injury. Augmented reality (AR) is a promising new technology that can accurately allow for intraoperative localization from skin through the intradural compartment. We present a case series evaluating the timing, steps, and accuracy at which this technology is able to enhance BIET resection., Methods: A protocol for MIS and open AR-guided BIET resection was developed and applied to determine the feasibility. The tumor is marked on diagnostic magnetic resonance imaging (MRI) using AR software. Intraoperatively, the planning MRI is fused with the intraoperative computed tomography. The position and size of the tumor is projected into the surgical microscope and directly into the surgeon's field of view. Intraoperative orientation is performed exclusively via navigation and AR projection. Demographic and perioperative factors were collected., Results: Eight patients were enrolled. The average operative time for MIS cases was 128 ± 8 minutes and for open cases 206 ± 55 minutes. The estimated intraoperative blood loss was 97 ± 77 mL in MIS and 240 ± 206 mL in open procedures. AR tumor location and margins were considered sufficiently precise by the surgeon in every case. Neither correction of the approach trajectory nor ultrasound assistance to localize the tumor were necessary in any case. No intraoperative complications were observed., Conclusion: Current findings suggest that AR may be a feasible technique for tumor localization in the MIS and open resection of benign spinal extramedullary tumors.

Objective: Minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) is a highly reproducible procedure for the fusion of spinal segments. We recently introduced the concept of "total navigation" to improve workflow and eliminate fluoroscopy. Imageguided surgery incorporating augmented reality (AR) may further facilitate workflow. In this study, we developed and evaluated a protocol to integrate AR into the workflow of MISTLIF., Methods: A case series of 10 patients was the basis for the evaluation of a protocol to facilitate tubular MIS-TLIF by the application of AR. Surgical TLIF landmarks were marked on a preoperative computed tomography (CT)-scan using dedicated software. This marked CT scan was fused intraoperatively with the low-dose navigation CT scan using elastic image fusion, and the markers were transferred to the intraoperative scan. Our experience with this workflow and the surgical outcomes were collected., Results: Our AR protocol was safely implemented in all cases. The TLIF landmarks could be preoperatively planned and transferred to the intraoperative imaging. Of the 10 cases, 1 case had additionally a synovial cyst resection and in 2 cases an additional bony decompression was performed due to central stenosis. The average procedure time was 160.6 ± 31.9 minutes. The AR implementation added 1.72 ± 0.37 minutes to the overall procedure time. No complications occurred., Conclusion: Our findings support the idea that total navigation with AR may further facilitate the workflow, especially in cases with more complex anatomy and for teaching and training purposes. More work is needed to simplify the software and make AR integration more user-friendly.

Study Design: Prospective case series., Objective: SSPSS (single step pedicle screw system) was developed for minimally invasive spine surgery. We performed this study to report on safety, workflow, and our initial clinical experience with this novel technique., Methods: The prospective study was conducted on patients who underwent pedicle screw fixation between October 2017 and April 2018 using a novel single step 3D navigated pedicle screw system for MIS. Outcome measurements were obtained from intraoperative computerized tomography. The images were evaluated to determine pedicle wall penetration. We used a grading system to assess the severity of the pedicle wall penetration. Breaches were classified as grade 1 (<2 mm), grade 2 (2-4 mm), or grade 3 (<4 mm), 1 and as cranial, caudal, medial, and lateral., Results: Our study includes 135 screws in 24 patients. SSPSS eliminated K-wires and multiple steps traditionally necessary for MIS pedicle screw insertion. The median time per screw was 2.45 minutes. 3 screws were corrected intraoperatively. Pedicle wall penetration occurred in 14 screws (10%). Grade 1 breaches occurred in 4 screws (3%) and grade 2 breaches occurred in 10 screws (7%). Lateral breaches were observed more often than medial breaches. The accuracy rate in our study was 90% (Grade 0 breach). No revision surgeries were needed and no complications occurred., Conclusions: Our study suggests that SSPSS could be a safe, accurate, and efficient tool. Our accuracy rate is comparable to that found in the literature.

Background: Spinal fractures are among the most common traumatic injuries in elderly patients, with the odontoid process being frequently affected. As this patient group usually has high rates of comorbidity and chronic diseases, a nonoperative approach may offer a reasonable solution for a favorable fracture pattern., Objective: We modified the procedure by implanting a bilateral atlantoaxial joint spacer (model DTRAX) into the joint space and review our experience utilizing this technique for the treatment of patients with a fracture of the odontoid process., Methods: A retrospective evaluation was performed on patients treated surgically for unstable traumatic fractures of the odontoid process. The stabilization was performed using a dorsal rod and screw instrumentation of the lateral mass of the atlas and the pars interarticularis of the axis. The procedure was further modified by implanting a bilateral atlantoaxial joint spacer (DTRAX) into the joint space bilaterally after the removal of the articular cartilage. Patients older than 70 years with a traumatic fracture of the odontoid process were included. Pain was assessed pre- and postoperatively using the visual analog scale (VAS). To verify fusion during follow-up, either x-ray imaging of the cervical spine or magnetic resonance imaging or computed tomography were performed., Results: A total of 5 patients were included in our study. Four patients had an American Society of Anesthesiology score of 3 and 1 had a score of 4. The average duration of surgery was 187 ± 38.1 minutes. The average blood loss during the procedure was 340 ± 270 mL. The average radiological follow-up period was 21.2 ± 17.5 months. Preoperatively, the average VAS pain score was 2.3 ± 3.3. Postoperatively, the mean VAS decreased to 0.6 ± 0.9. The average follow-up period for pain was 27.2 ± 19 months. No patient showed neurological deficits before or after surgery. Follow-up demonstrated solid fusion in all cases., Conclusion: The fusion of the atlantoaxial joint with bilateral atlantoaxial joint spacers represents a suitable and feasible option for achieving high fusion rates in elderly patients with odontoid fractures., Clinical Relevance: A significant percentage of patients who are treated non-operatively will experience nonunion, which may cause instability of the atlantoaxial joint. Posterior fixation with screws and rods is a treatment option, but it leaves the cartilaginous joint surface in place, which can be an impediment to the fusion process. In other cases, degenerative collapse of the C1/C2 joint can cause compression of the C2 nerve root., Competing Interests: Declaration of Conflicting Interests: The authors report no conflicts of interest in this work., (This manuscript is generously published free of charge by ISASS, the International Society for the Advancement of Spine Surgery. Copyright © 2022 ISASS. To see more or order reprints or permissions, see http://ijssurgery.com.)

Objective: Telemedicine technology has been developed to allow surgeons in countries with limited resources to access expert technical guidance during surgical procedures. The authors report their initial experience using state-of-the-art wearable smart glasses with wireless capability to transmit intraoperative video content during spine surgery from sub-Saharan Africa to experts in the US., Methods: A novel smart glasses system with integrated camera and microphone was worn by a spine surgeon in Dar es Salaam, Tanzania, during 3 scoliosis correction surgeries. The images were transmitted wirelessly through a compatible software system to a computer viewed by a group of fellowship-trained spine surgeons in New York City. Visual clarity was determined using a modified Snellen chart, and a percentage score was determined on the smallest line that could be read from the 8-line chart on white and black backgrounds. A 1- to 5-point scale (from 1 = unrecognizable to 5 = optimal clarity) was used to score other visual metrics assessed using a color test card including hue, contrast, and brightness. The same scoring system was used by the group to reach a consensus on visual quality of 3 intraoperative points including instruments, radiographs (ability to see pedicle screws relative to bony anatomy), and intraoperative surgical field (ability to identify bony landmarks such as transverse processes, pedicle screw starting point, laminar edge)., Results: All surgeries accomplished the defined goals safely with no intraoperative complications. The average download and upload connection speeds achieved in Dar es Salaam were 45.21 and 58.89 Mbps, respectively. Visual clarity with the modified white and black Snellen chart was 70.8% and 62.5%, respectively. The average scores for hue, contrast, and brightness were 2.67, 3.33, and 2.67, respectively. Visualization quality of instruments, radiographs, and intraoperative surgical field were 3.67, 1, and 1, respectively., Conclusions: Application of smart glasses for telemedicine offers a promising tool for surgical education and remote training, especially in low- and middle-income countries. However, this study highlights some limitations of this technology, including optical resolution, intraoperative lighting, and internet connection challenges. With continued collaboration between clinicians and industry, future iterations of smart glasses technology will need to address these issues to stimulate robust clinical utilization.

Objective: Degenerative cervical myelopathy (DCM) is an important public health issue. Surgery is the mainstay of treatment for moderate and severe DCM. Delayed discharge of patients after DCM surgery is associated with increased healthcare costs. There is a paucity of data regarding predictive factors for discharge destination after scheduled surgery for patients with DCM. The purpose of this study was to identify factors predictive of home versus nonhome discharge after DCM surgery., Methods: Patients undergoing scheduled DCM surgery who had been enrolled in a prospective DCM substudy of the Canadian Spine Outcomes and Research Network registry between January 2015 and October 2020 were included in this retrospective analysis. Patient data were evaluated to identify potential factors predictive of home discharge after surgery. Logistic regression was used to identify independent factors predictive of home discharge. A multivariable model was then used as a final model., Results: Overall, 639 patients were included in the initial analysis, 543 (85%) of whom were discharged home. The mean age of the entire cohort was 60 years (SD 11.8 years), with a BMI of 28.9 (SD 5.7). Overall, 61.7% of the patients were female. The mean length of stay was 2.72 days (SD 1.7 days). The final internally validated bootstrapped multivariable model revealed that younger age, higher 9-Item Patient Health Questionnaire score, lower Neck Disability Index scores, fewer operated levels, mJOA scores indicating mild disease, anterior cervical discectomy and fusion procedure, and no perioperative adverse effects were predictive of home discharge., Conclusions: Younger age, less neck-related disability, fewer operated levels, more significant depression, less severe myelopathy, anterior cervical discectomy and fusion procedure, and no perioperative adverse effects are predictive of home discharge after surgery for DCM. These factors can help to guide clinical decision-making and optimize postoperative care pathways.

Background: To identify, analyze, and report the patient- and procedure-related factors associated with surgical site infection (SSI) after spinal fusion (SF) surgery., Methods: We included any SSI-SF from January 2013 to September 2015. A total of 989 spine surgeries that required instrumentation were performed., Results: Twenty-four out of 989 (2.43%) patients presented with SSI. More than half of the SSI cases (54%) got infected with either exclusively gram-negative bacteria or a combination of gram-negative and gram-positive bacteria; 9.1% of the surgeries involved the sacral spine (90 out of 989 patients). SSI in long constructs (more than 3 levels) was performed in 66.7% compared with 33.3% with short constructs; 87.5 % of the reported SSI (21 patients) were done through a posterior approach. Of patients who had SSI, 87.5% received prophylactic antibiotics, 92% were operated on during the daytime shift, 50% required blood transfusion, and 79% required surgical debridement. Four patients out of 24 patients died (17%) due to unrelated SSI complications., Conclusions: The overall incidence of gram-negative infections after long SFs remains low in our study population. Despite this low overall incidence, our results demonstrate a relative higher incidence of gram-negative SSIs in surgeries involving more than 3 spinal levels and for all those involving the sacral spine. We propose that there may be a potential benefit of gram-negative prophylactic antibiotic coverage in patients falling in either 1 of these categories. Further multivariate analysis and/or randomized studies may be necessary to confirm our results., Level of Evidence: 3., (This manuscript is generously published free of charge by ISASS, the International Society for the Advancement of Spine Surgery. Copyright © 2021 ISASS.)

Objective: The objective of this study was to determine the publication rate of abstracts presented at the annual meetings of the AANS/CNS Section on Disorders of the Spine and Peripheral Nerves (Spine Summit)., Methods: The authors used a search algorithm in PubMed to determine the publication rate of abstracts presented at the Spine Summit from 2007 to 2012. The variables assessed were presentation modality, topic, meeting year, publication year, destiny journal and its 5-year impact factor (IF), country, and citation count (retrieved from the Scopus database)., Results: One thousand four hundred thirty-six abstracts were analyzed; 502 were oral presentations and 934 were digital poster presentations. The publication rate was 53.97% (775/1436). The mean time from presentation to publication was 1.35 ± 1.97 years (95% CI 1.21-1.49 years). The mean citation count of published articles was 40.55 ± 55.21 (95% CI 36.66-44.44). Oral presentations had a higher publication rate (71.51%, 359/502) than digital posters (44.54%, 416/934; OR 3.13, 95% CI 2.48-3.95, p < 0.001). Oral presentations had a higher number of citations (55.51 ± 69.00, 95% CI 48.35-62.67) than digital posters (27.64 ± 34.88, 95% CI 24.28-31.00, p < 0.001). The mean IF of published articles was 3.48 ± 2.91 (95% CI 3.27-3.70). JNS: Spine (191/775, 24.64%), Spine (103/775, 13.29%), and Neurosurgery (56/775, 7.23%) had the greatest number of published articles. The US represented the highest number of published articles (616/775, 79.48%)., Conclusions: The publication rate of the Spine Summit is among the highest compared to other spine meetings. Many of the abstracts initially presented at the meeting are further published in high-IF journals and had a high citation count. Therefore, the Spine Summit maintains its high standards of scientific papers, which reflects the high quality of the research performed in the spine surgery field in North America.

Background: Sagittal alignment is an important consideration in spine surgery. The literature is conflicted regarding the effect of minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) on sagittal parameters and the role of expandable cage technology., Objective: To compare lordosis generated by static and expandable cages and to determine what factors affect postoperative sagittal parameters., Methods: Preoperative regional lordosis (RL), segmental lordosis (SL), and posterior disc height (PDH) were compared to postoperative values in single-level MI-TLIF performed using expandable or static cages. Patients were stratified based on preoperative SL: low lordosis (<15 degrees), moderate lordosis (15-25 degrees), and high lordosis (>25 degrees). Regression analyses were conducted to determine factors associated with postoperative SL and PDH., Results: Of the 171 patients included, 111 were in the static and 60 in the expandable cohorts. Patients with low preoperative lordosis experienced an increase in SL and maintained RL regardless of cage type. Those with moderate to high preoperative lordosis experienced a decrease in SL and RL with the static cage, but maintained SL and RL with the expandable cage. Although both cohorts showed an increase in PDH, the increase in the expandable cohort was greater. Preoperative SL was predictive of postoperative SL; preoperative SL, preoperative PDH, and cage type were predictive of postoperative PDH., Conclusion: Expandable cages showed favorable results in restoring disc height and maintaining lordosis in the immediate postoperative period. Preoperative SL was the most significant predictor of postoperative SL. Thus, preoperative radiographic parameters and goals of surgery should be important considerations in surgical planning., (Copyright © 2019 by the Congress of Neurological Surgeons.)

Degenerative lumbar spine disease (DLSD) is a heterogenous group of conditions that can significantly affect patients' quality of life. Lateral lumbar interbody fusion (LLIF) is one of the treatment modalities for DLSD that has been increasing in popularity over the past decade. The treatment of DLSD should be individualized based on patients' symptoms and characteristics to maximize outcomes., Methods: Literature review, invited review., Results: In this article, we will (1) review the use of the LLIF technique in the treatment of degenerative lumbar spine disease, (2) review the current concepts of LLIF, and (3) explore the evidence to date that will allow the reader to maximize the benefits of this technique., Conclusions: LLIF is an alternative for the treatment of degenerative pathologies of the lumbar spine via indirect decompression., Competing Interests: Declaration of Conflicting Interests: The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article., (© The Author(s) 2020.)

Study Design: Systematic review., Objective: To date there is no consensus among surgeons as to what defines an MIS-TLIF (transforaminal lumbar interbody fusion using minimally invasive spine surgery) compared to an open or mini-open TLIF. This systematic review aimed to examine the MIS-TLIF techniques reported in the recent body of literature to help provide a definition of what constitutes the MIS-TLIF, based on the consensus of the majority of surgeons., Methods: We created a database of articles published about MIS-TLIF between 2010 and 2018. We evaluated the technical components of the MIS-TLIF including instruments and incisions used as well the order in which key steps are performed., Results: We could identify several patterns for MIS-TLIF performance that seemed agreed upon by the majority of MIS surgeons: use of paramedian incisions; use of a tubular retractor to perform a total facetectomy, decompression, and interbody cage implantation; and percutaneous insertion of the pedicle-screw rod constructs with intraoperative imaging., Conclusion: Based on this review of the literature, the key features used by surgeons performing MIS TLIF include the use of nonexpandable or expandable tubular retractors, a paramedian or lateral incision, and the use of a microscope or endoscope for visualization. Approaches using expandable nontubular retractors, those that require extensive subperiosteal dissection from the midline laterally, or specular-based retractors with wide pedicle to pedicle exposure are far less likely to be promoted as an MIS-based approach. A definition is necessary to improve the communication among spine surgeons in research as well as patient education., Competing Interests: Declaration of Conflicting Interests: The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: RH has received funding from AOSpine, Brainlab, DePuy Synthes, Lanx, and the Carol and Grace Hansen Spinal Research Foundation. The other authors have no personal, financial, or institutional interest in any of the drugs, materials, or devices described in this article., (© The Author(s) 2019.)

Background: In patients with symptomatic lumbar stenosis undergoing lateral transpsoas approach for lumbar interbody fusion (LLIF) surgery, it is not always clear when indirect decompression is sufficient in order to achieve symptom resolution. Indirect decompression failure (IDF), defined as "postoperative persistent symptoms of nerve compression with or without a second direct decompression surgery to reach adequate symptom resolution," is not widely reported. This information, however, is critical to better understand the indications, the potential, and the limitations of indirect decompression., Objective: The purpose of this study was to systematically review the current literature on IDF after LLIF., Methods: A literature search was performed on PubMed. We included randomized controlled trials and prospective, retrospective, case-control studies, and case reports. Information on sample size, demographics, procedure, number and location of involved levels, follow-up time, and complications were extracted., Results: After applying the exclusion criteria, we included 9 of the 268 screened articles that reported failure. A total of 632 patients were screened in these articles and detailed information was provided. Average follow-up time was 21 months. Overall reported incidence of IDF was 9%., Conclusion: Failures of decompression via LLIF are inconsistently reported and the incidence is approximately 9%. IDF failure in LLIF may be underreported or misinterpreted as a complication. We propose to include the term "IDF" as described in this article to differentiate them from complications for future studies. A better understanding of why IDF occurs will allow surgeons to better plan surgical intervention and will avoid revision surgery., Competing Interests: Declaration of Conflicting Interests: The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: Roger Härtl is a consultant for Ulrich, Brainlab, DePuy-Synthes, and he has royalties from Zimmer. The other authors have no conflicts of interest to disclose., (© The Author(s) 2019.)

Study Design: Technical note, retrospective case series., Objective: Lumbar stenosis can be effectively treated using tubular unilateral laminotomy for bilateral decompression (ULBD). For multilevel stenosis, a multilevel ULBD through separate, alternating crossover approaches has been described as the "slalom technique." To increase efficacy, we introduced this approach with 2 microscopes simultaneously., Methods: We collected data on 13 patients, with multilevel lumbar stenosis, operated at our institution between 2015 and 2016 by the aforementioned technique. We assessed surgical time (ST), estimated blood loss (EBL), complications, and revision surgeries. Furthermore, we provide a stepwise instruction for performing the tandem microscopic slalom technique in a safe and efficient manner., Results: The mean age of the patients was 68 ± 8 years. The ST per level was 68 ± 19 minutes with an EBL per level of 39 ± 30 mL. We had no intraoperative complications and none of our patients required a revision surgery during a mean follow-up of 12 months., Conclusions: We have shown that this technique is feasible and can be performed safely for multisegmental lumbar spinal stenosis with minimal tissue trauma and low EBL. Furthermore, randomized controlled studies with a larger sample size may be necessary to drive any final conclusions., Competing Interests: Declaration of Conflicting Interests: The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: Roger Härtl receives consultant fees from DePuy Synthes, Brainlab, and Ulrich and royalties from Zimmer Biomet., (© The Author(s) 2019.)

Tissue-engineered approaches for the treatment of early-stage intervertebral disc degeneration have shown promise in preclinical studies. However, none of these therapies has been approved for clinical use, in part because each therapy targets only one aspect of the intervertebral disc's composite structure. At present, there is no reliable method to prevent intervertebral disc degeneration after herniation and subsequent discectomy. Here, we demonstrate the prevention of degeneration and maintenance of mechanical function in the ovine lumbar spine after discectomy by combining strategies for nucleus pulposus augmentation using hyaluronic acid injection and repair of the annulus fibrosus using a photocrosslinked collagen patch. This combined approach healed annulus fibrosus defects, restored nucleus pulposus hydration, and maintained native torsional and compressive stiffness up to 6 weeks after injury. These data demonstrate the necessity of a combined strategy for arresting intervertebral disc degeneration and support further translation of combinatorial interventions to treat herniations in the human spine., (Copyright © 2020 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.)

Background: Minimally invasive techniques utilizing tubular retractors have become an increasingly popular approach to the spinal column. The concept of a unilateral laminotomy for bilateral decompression (ULBD), first applied in the lumbar spine, has recently been applied to the cervical spine for the treatment of cervical spondylotic myelopathy (CSM). A better understanding of the indications and surgical techniques is required to effectively educate surgeons on how to appropriately and safely perform tubular cervical laminotomy via ULBD., Objective: To describe a 10-step technique for minimally invasive cervical laminotomy and report our early clinical experience., Methods: A retrospective review identified 15 patients with CSM who were treated with this procedure. Visual analogue scale (VAS), neck disability index (NDI), and modified Japanese Orthopaedic Association (mJOA) scores were obtained pre- and postoperatively., Results: The mean age of the 15 patients was 73.1 ± 6.8 yr. The median number of levels treated was 1 (range 1-3). Mean operative time was 125.3 ± 30.8 or 81.7 ± 19.2 min per level. Mean estimated blood loss was 57.3 ± 24.6 cc. Median postoperative hospital length of stay was 36 h. No complications were encountered. Median follow-up was 18 mo. Mean pre- and postoperative VAS were 6.4 ± 2.4 and 1.0 ± 0.8, respectively (P < .001). Mean pre- and postoperative NDI were 46.4 ± 19.2 and 7.0 ± 6.9, respectively (P < .001). Mean pre- and postoperative Mjoa were 11.3 ± 2.5 and 14.5 ± 0.5, respectively (P < .001)., Conclusion: In our early clinical experience, minimally invasive cervical ULBD is safe and effective. Adherence to the presented 10-step technique will allow surgeons to safely address bilateral cervical pathology while avoiding complications., (Copyright © 2019 by the Congress of Neurological Surgeons.)

This video demonstrates the workflow of a minimally invasive transforaminal interbody fusion (MIS-TLIF) using a portable intraoperative CT (iCT) scanner, (Airo®, Brainlab AG, Feldkirchen, Germany), combined with state-of-the-art total 3D computer navigation. The navigation is used not only for instrumentation but also for intraoperative planning throughout the procedure, inserting the cage, therefore, completely eliminating the need for fluoroscopy. In this video, we present a case of a 72-yr-old female patient with a history of lower back pain, right lower extremity radicular pain and weakness for 2 yr due to L4-L5 spondylolisthesis with instability and severe lumbar spinal stenosis. The patient is treated by a L4-L5 unilateral laminotomy for bilateral decompression (ULBD) and MIS-TLIF. MIS-TLIF using total 3D navigation significantly improves the workflow of the conventional TLIF procedure. The tailored access to the spine is translated into smaller but more efficient surgical corridors. This modification in a "total navigation" modality minimizes the staff radiation exposure to 0 by navigating in real time over iCT obtained images that can be acquired while the surgical staff is protected or outside the OR. Furthermore, this technique makes real-time and virtual intraoperative imaging of screws and their planned trajectory feasible. 3D Navigation eliminates the need for K-Wires, thus decreasing the risk of vascular penetration injury due to K-Wire malpositioning. 3D navigation can also predict the positioning of the interbody cage, thereby, decreasing the risk of malpositioning or subsidence. Patient consent was obtained prior to performing the procedure., (Copyright © 2019 by the Congress of Neurological Surgeons.)

Early-onset scoliosis (EOS) correction techniques have evolved slowly over the past 40 years and still remain a challenge for the spine surgeon. Avoiding spinal fusion in these patients is key to decreasing morbidity and mortality in this population. Current treatments for EOS include both conservative and surgical options. The authors present the modified Luqué technique that has been performed at their institution for the past decade. This modified technique relies on Luqué's principle, but with newer "gliding" implants through a less disruptive approach. The goal of this technique is to delay fusion as long as possible, with the intent to prevent deformity progression while preserving maximal growth. Normally, these patients will have definitive fusion surgery once they have reached skeletal maturity or as close as possible. Out of 23 patients until present (close to 4-year follow-up), the authors have not performed any revision due to implant failure. Three patients have undergone final fusion as the curve progressed (one patient, 4 years out, had final fusion at age 12 years; two other patients had final fusion at 3 years). These implants, which have the CE mark in Europe, are available in Canada via a special access process with Health Canada. The implants have not yet been submitted to the FDA, as they are waiting on clinical data out of Europe and Canada. In the following video the authors describe the modified Luqué technique step-by-step. The video can be found here: https://youtu.be/k0AuFa9lYXY., Competing Interests: Disclosures The authors report no conflict of interest concerning the materials or methods used in this study or the findings specified in this publication., (© 2020, Rodrigo Navarro-Ramirez, Oded Rabau, Alisson Teles, Susan Ge, Abdulaziz Bin Shebreen, Neil Saran, and Jean Ouellet.)

The peculiarity of extreme lateral interbody fusion (LLIF) is the achievement of indirect neural decompression of the spinal canal while distracting the intervertebral disc space using an interbody cage. In this manuscript we will review the potentials and limitations of this technique when treating degenerative disc disease of the lumbar spine. A literature search of the PubMed-National Library of Medicine was performed. Only articles in English were included. The current available literature demonstrates that LLIF is an effective method to decompress foraminal and central canal stenosis. Based on the current available literature LLIF effects on lateral recess stenosis are less consistent. The aim of this review is to provide with a thorough overview of the latest literature available and provide the audience with targeted-oriented published results that will eventually improve the decision-making process when using the LLIF technique.

Background: Our group has previously demonstrated in vivo annulus fibrosus repair in animal models using an acellular, riboflavin crosslinked, high-density collagen (HDC) gel., Objective: To assess if seeding allogenic mesenchymal stem cells (MSCs) into this gel yields improved histological and radiographic benefits in an in vivo sheep model of annular injury., Methods: Fifteen lumbar intervertebral discs (IVDs) were randomized into 4 groups: intact, injury only, injury + acellular gel treatment, or injury + MSC-seeded gel treatment. Sheep were sacrificed at 6 wk. Disc height index (DHI), Pfirrmann grade, nucleus pulposus area, and T2 relaxation time (T2-RT) were calculated for each IVD and standardized to healthy controls from the same sheep. Quantitative histological assessment was also performed using the Han scoring system., Results: All treated IVDs retained gel plugs on gross assessment and there were no adverse perioperative complications. The MSC-seeded gel treatment group demonstrated statistically significant improvement over other experimental groups in DHI (P = .002), Pfirrmann grade (P < .001), and T2-RT (P = .015). There was a trend for greater Han scores in the MSC-seeded gel-treated discs compared with injury only and acellular gel-treated IVDs (P = .246)., Conclusion: MSC-seeded HDC gel can be delivered into injured IVDs and maintained safely in live sheep to 6 wk. Compared with no treatment and acellular HDC gel, our data show that MSC-seeded HDC gel improves outcomes in DHI, Pfirrmann grade, and T2-RT. Histological analysis shows improved annulus fibrosus and nucleus pulposus reconstitution and organization over other experimental groups as well., (Copyright © 2018 by the Congress of Neurological Surgeons.)

Objective: Spinal trauma is a major cause of disability worldwide. The burden is especially severe in low-income countries, where hospital infrastructure is poor, resources are limited, and the volume of cases is high. Currently, there are no reliable data available on incidence, management, and outcomes of spinal trauma in East Africa. The main objective of this study was to describe, for the first time, the demographics, management, costs of surgery and implants, treatment decision factors, and outcomes of patients with spine trauma in Tanzania., Methods: The authors retrospectively reviewed prospectively collected data on spinal trauma patients in the single surgical referral center in Tanzania (Muhimbili Orthopaedic Institute [MOI]) from October 2016 to December 2017. They collected general demographics and the following information: distance from site of trauma to the center, American Spinal Injury Association Impairment Scale (AIS), time to surgery, steroid use, and mechanism of trauma and AOSpine classification and costs. Surgical details and complications were recorded. Primary outcome was neurological status on discharge. The authors analyzed surgical outcome and determined predicting factors for positive outcome., Results: A total of 180 patients were included and analyzed in this study. The mean distance from site of trauma to MOI was 278.0 km, and the time to admission was on average 5.9 days after trauma. Young males were primarily affected (82.8% males, average age 35.7 years). On admission, 47.2% of patients presented with AIS grade A. Most common mechanisms of injury were motor vehicle accidents (28.9%) and falls from height (32.8%). Forty percent of admitted patients underwent surgery. The mean time to surgery was 33.2 days; 21.4% of patients who underwent surgery improved in AIS grade at discharge (p = 0.030). Overall, the only factor associated with improvement in neurological status was undergoing surgery (p = 0.03) and shorter time to surgery (p = 0.02)., Conclusions: This is the first study to describe the management and outcomes of spinal trauma in East Africa. Due to the lack of referral hospitals, patients are admitted late after trauma, often with severe neurological deficit. Surgery is performed but generally late in the course of hospital stay. The decision to perform surgery and timing are heavily influenced by the availability of implants and economic factors such as insurance status. Patients with incomplete deficits who may benefit most from surgery are not prioritized. The authors' results suggest that surgery may have a positive impact on patient outcome. Further studies with a larger sample size are needed to confirm our results. These results provide strong support to implement evidence-based protocols for the management of spinal trauma.

Background: Bow hunter syndrome describes a mechanical compression of the vertebral artery on head rotation leading to reversible symptomatic vertebrobasilar insufficiency. Patients are commonly presenting with syncope, vertigo, dizziness, and visual disturbances. These symptoms usually resolve when the head is turned back into neutral position. Treatment options involve surgical decompression with or without fusion, bypass surgery, or endovascular intervention., Case Description: We report about a 49-year-old female who presented with vague neck pain and severe vertigo, nausea, and near syncope when her head turned up and right. Computed tomography angiography revealed a pseudoaneurysm at the dominant left V3 and near total occlusion of the left vertebral artery as it exited the C2 foramen when the head was turned to the previously mentioned position. The patient could be successfully treated by computed tomography-navigated posterior instrumentation using bilateral C1 lateral mass screws and C2 translaminar screws. To promote segmental fusion, bilateral intrafacet cages were implanted. Postoperatively, the patient remained without neurologic deficits and experienced no further episodes of the preoperatively reported transient vertebrobasilar insufficiency symptoms., Conclusions: The reported case is unique as the bow hunter syndrome was further complicated by a pseudoaneurysm of the V3 segment. Surgical intervention proved to be an efficient treatment by stabilizing the affected segment in this patient., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Symptomatic lumbar spondylolisthesis is commonly accompanied by spinal stenosis in multiple segments. These pathologies are routinely treated by multilevel decompression and instrumented fusion. However, it was hypothesized that a minimally invasive surgery (MIS) fusion in the unstable segment combined with a unilateral laminotomy for bilateral decompression (ULBD) in the adjacent stenotic segment is a biomechanically feasible alternative to a two-level fusion and superior to open laminectomy adjacent to a fused segment. This concept has demonstrated success in a recently published biomechanical cadaver study performed by our group. The present article offers a detailed step by step technical description for an MIS-TLIF (transforaminal lumbar interbody fusion) with adjacent ULBD., Competing Interests: Conflicts of Interest: R Härtl is a consultant for DePuy-Synthes, Ulrich and Brainlab and receives royalties from Zimmer. The other authors have no conflicts of interest to declare.

Background: Superficial siderosis of the central nervous system is a rare neurologic disorder characterized by the superficial deposition of hemosiderin in the subpial layer resulting in iron-related progressive neurodegeneration., Case Description: In this report, we present a case of superficial siderosis of the central nervous system secondary to an intradural thoracic disk herniation causing a cerebrospinal fluid (CSF) leak., Conclusions: The patient was successfully treated with T6-T8 transpedicular partial corpectomy, as well as diskectomy with decompression followed by watertight closure of the CSF leak. Intraoperative watertight closure of the CSF leak was achieved., (Copyright © 2018. Published by Elsevier Inc.)

Objective: The aim is assessing the in vivo efficacy of annulus fibrosus (AF) cells seeded into collagen by enhancing the reparative process around annular defects and preventing further degeneration in a rat-tail model., Summary of Background Data: Treating disc herniation with discectomy may relieve the related symptoms but does not address the underlying pathology. The persistent annular defect may lead to re-herniation and further degeneration. We recently demonstrated that riboflavin crosslinked high-density collagen gels (HDC) can facilitate annular repair in vivo., Methods: 42 rats, tail disc punctured with an 18-gauge needle, were divided into 3 groups: untreated (n = 6), injected with crosslinked HDC (n = 18), and injected with AF cell-laden crosslinked HDC (n = 18). Ovine AF cells were mixed with HDC gels prior to injection. X-rays and MRIs were conducted over 5 weeks, determining disc height index (DHI), nucleus pulposus (NP) size, and hydration. Histological assessments evaluated the viability of implanted cells and degree of annular repair., Results: Although average DHIs of both HDC gel groups were higher than those of the puncture control group at 5 weeks, the retention of disc height, NP size and hydration at 1 and 5 weeks was significant for the cellular group compared to the punctured, and at 5 weeks to the acellular group. Histological assessment indicated that AF cell-laden HDC gels have accelerated reparative sealing compared to acellular HDC gels., Conclusions: AF cell-laden HDC gels have the ability of better repairing annular defects than acellular gels after needle puncture., Statement of Significance: This project addresses the compelling demand of a sufficient treatment strategy for degenerative disc disease (DDD) perpetuated by annulus fibrosus (AF) injury, a major cause of morbidity and burden to health care systems. Our study is designed to answer the question of whether injectable, photo-crosslinked, high density collagen gels can seal defects in the annulus fibrosus of rats and prevent disc degeneration. Furthermore, we investigated whether the healing of AF defects will be enhanced by the delivery of AF cells (fibrochondrocytes) to these defects. The use of cell-laden collagen gels in spine surgery holds promise for a wide array of applications, from current discectomy procedures to future nucleus pulposus reparative therapies, and our group is excited about this potential., (Copyright © 2018. Published by Elsevier Ltd.)

Total disc replacement using tissue-engineered intervertebral discs (TE-IVDs) may offer a biological alternative to treat radiculopathy caused by disc degeneration. A composite TE-IVD was previously developed and evaluated in rat tail and beagle cervical spine models in vivo. Although cell viability and tissue integration into host tissue were promising, significant implant displacement occurred at multiple spinal levels. The goal of the present study was to assess the effects of a resorbable plating system on the stiffness of motion segments and stability of tissue-engineered implants subjected to axial compression. Canine motion segments from levels C2/C3 to C5/C6 were assessed as intact (CTRL), after discectomy (Dx), with an implanted TE-IVD only (PLATE-), and with a TE-IVD combined with an attached resorbable plate (PLATE+). Segments under PLATE+ conditions fully restored separation between endplates and showed significantly higher compressive stiffness than segments under PLATE- conditions. Plated segments partially restored more than 25% of the CTRL motion segment stiffness. Plate attachment also prevented implant extrusion from the disc space at 50% compressive strain, and this effect was more significant in segments from levels C3/C4 when compared to segments from level C5/C6. These results suggest that stabilization of motion segments via resorbable plating assists TE-IVD retention in the disc space while allowing the opportunity for implants to fully integrate into the host tissue and achieve optimal restoration of spine biomechanics., Competing Interests: L.J.B. is a co‐founder and holds equity in 3DBio Corp. R.H. is a consultant and holds equity in 3DBio Corp. R.H. has the following disclosures: Consulting fees: AOSpine, Brainlab, Depuy‐Synthes, Lanx, and Supported/Contracted research: Baxter.

Giant schwannomas are defined as intradural extramedullary tumors that span >2 vertebral body lengths. Although uncommon, these lesions can cause significant mass effect on the spinal cord and subsequent neurologic compromise. Gross total resection is the goal of operative intervention, however, is extremely challenging in cases where the tumor occupies a ventral, midline position within the lower cervical thecal sac. Using a representative case presentation, we describe an adult male with insidious progression of upper extremity radicular pain and paresthesias, found to have a ventral, solid/cystic C5-C7 giant schwannoma. We demonstrate the step-by-step surgical technique for an anterior approach 2-level cervical corpectomy, microsurgical resection of an intradural giant schwannoma, watertight dural closure, and lastly 360-degrees instrumented stabilization of the cervicothoracic spine. In addition we incorporate the utilization of a portable intraoperative computed tomography for stereotactic localization and 3-dimensional navigation-guided screw implantation. Finally, we discuss various preoperative, perioperative, and postoperative considerations that can have profound impact on successful outcomes.

Study Design: Ovine in vivo study., Objective: To perform lateral approach lumbar surgery in an ovine model to administer an injectable riboflavin cross-linked high-density collagen (HDC) gel and to assess its ability to mitigate intervertebral disc (IVD) degeneration after induced annulus fibrosus (AF) injury., Summary of Background Data: Biological-based injectable gels have shown efficacy in restoring biomechanical, radiographic, and histological parameters in IVD-injured animal models. Riboflavin cross-linked HDC gel has previously demonstrated retention of nucleus pulposus (NP) tissue, reduced loss of disc height, and prevention of terminal cellular degenerative changes in rat-tail spines. However, this biological therapy has never been tested in large animal models., Methods: Forty lumbar IVDs were accessed from eight sheep via lateral approach surgery. IVDs were randomly assigned to healthy control, injury and HDC treatment, or negative control with injury and no treatment. IVD injury was carried out using a drill-bit through the AF followed by needle puncture of the NP. Sheep were followed for 16 weeks and underwent qualitative/quantitative magnetic resonance imaging, x-ray, and histological analyses of collagen and proteoglycan content., Results: The lateral approach to the ovine lumbar spine to deliver HDC gel proved to be safe and reproducible. IVDs treated with the HDC gel revealed less degenerative changes at the microscopic level based on AF and NP histology. However, mean Pfirrmann grade, T2 relaxation time, NP voxel size, and disc height index were not significantly different between the two injury groups., Conclusion: Injectable HDC gel can be administered safely via lateral approach surgery in an ovine AF injury model. IVDs treated with HDC gel demonstrated less degeneration at the microscopic level though radiographic changes were slight when comparing treated to untreated IVDs. Future studies will need to elucidate the role of injury technique and time frame for follow-up in correlating histological and radiographical outcomes., Level of Evidence: N /A.

Study Design: This is a retrospective single-center study., Objective: The aim of the study was to evaluate the impact of cage characteristics and position toward clinical and radiographic outcome measures in patients undergoing extreme lateral interbody fusion (ELIF)., Summary of Background Data: ELIF is utilized for indirect decompression and minimally invasive surgical treatment for various degenerative spinal disorders. However, evidence regarding the influence of cage characteristics in patient outcome is minimal., Materials and Methods: Patients undergoing ELIF between 2007 and 2011 were included in a retrospective study. Demographic and perioperative data, as well as cage characteristics and side of approach were extracted. Radiographic parameters including lumbar lordosis, foraminal height, and disc height as well as clinical outcome parameters (Oswestry Disability Index and Visual Analog Scale) were measured preoperatively, postoperatively, and at the latest follow-up examination. Cage dimensions, in situ position, and type were correlated with radiographic and clinical outcome parameters., Results: In total, 84 patients with a total of 145 functional spinal units were analyzed. At the last follow-up of 17.7 months, radiographic and clinical outcome measures revealed significant improvement compared with before surgery with both, 18 and 22 mm cage anterior-posterior diameter subgroups (P≤0.05). Among cage characteristics, 22 mm cages presented superior restoration of foraminal and disc heights compared with 18 mm cages (P≤0.05). Neither position of the cage (anterior vs. posterior), nor the type (parallel vs. lordotic) had a significant impact on restoration of foraminal height and lumbar lordosis. Moreover, the side of surgical approach did not influence the amount of foraminal height increase., Conclusions: Cage anterior-posterior diameter is the determining factor in restoration of foraminal height in ELIF. Cage height, type, positioning, and side of approach do not have a determining role in radiographic outcome in the present study. Sustainable foraminal height restoration is achieved by implantation of wider cages., Level of Evidence: Level 3.

Background: Two-dimensional radiographic methods have been proposed to evaluate the radiographic outcome after indirect decompression through extreme lateral interbody fusion (XLIF). However, the assessment of neural decompression in a single plane may underestimate the effect of indirect decompression on central canal and foraminal volumes. The present study aimed to assess the reliability and consistency of a novel 3-dimensional radiographic method that assesses neural decompression by volumetric analysis using a new generation of intraoperative fan-beam computed tomography scanner in patients undergoing XLIF., Methods: Prospectively collected data from 7 patients (9 levels) undergoing XLIF was retrospectively analyzed. Three independent, blind raters using imaging analysis software performed volumetric measurements pre- and postoperatively to determine central canal and foraminal volumes. Intrarater and Interrater reliability tests were performed to assess the reliability of this novel volumetric method., Results: The interrater reliability between the three raters ranged from 0.800 to 0.952, P < 0.0001. The test-retest analysis on a randomly selected subset of three patients showed good to excellent internal reliability (range of 0.78-1.00) for all 3 raters. There was a significant increase in mean volume ≈20% for right foramen, left foramen, and central canal volumes postoperatively (P = 0.0472; P = 0.0066; P = 0.0003, respectively)., Conclusions: Here we demonstrate a new volumetric analysis technique that is feasible, reliable, and reproducible amongst independent raters for central canal and foraminal volumes in the lumbar spine using an intraoperative computed tomography scanner., (Copyright © 2017. Published by Elsevier Inc.)

Background: Minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) is an increasingly popular procedure with several potential advantages over traditional open TLIF., Objective: The current study aimed to compare fusion rates of different graft materials used in MIS-TLIF, via meta-analysis of the published literature., Methods: A Medline search was performed and a database was created including patient's type of graft, clinical outcome, fusion rate, fusion assessment modality, and duration of follow-up. Meta-analysis of the fusion rate was performed using StatsDirect software (StatsDirect Ltd, Cheshire, United Kingdom)., Results: A total of 1533 patients from 40 series were included. Fusion rates were high, ranging from 91.8% to 99%. The imaging modalities used to assess fusion were computed tomography scans (30%) and X-rays (70%). Comparison of all recombinant human bone morphogenetic protein (rhBMP) series with all non-rhBMP series showed fusion rates of 96.6% and 92.5%, respectively. The lowest fusion rate was seen with isolated use of autologous local bone (91.8%). The highest fusion rate was observed with combination of autologous local bone with bone extender and rhBMP (99.1%). The highest fusion rate without the use of BMP was seen with autologous local bone + bone extender (93.1%). The reported complication rate ranged from 0% to 35.71%. Clinical improvement was observed in all studies., Conclusion: Fusion rates are generally high with MIS-TLIF regardless of the graft material used. Given the potential complications of iliac bone harvesting and rhBMP, use of other bone graft options for MIS-TLIF is reasonable. The highest fusion rate without the use of rhBMP was seen with autologous local bone plus bone extender (93.1%)., (Published by Oxford University Press on behalf of Congress of Neurological Surgeons 2017. This work is written by (a) US Government employee(s) and is in the public domain in the US.)