Ruptured Anterior Inferior Cerebellar Artery Aneurysm From a Persistent Trigeminal Artery: A Case Report.

Persistent trigeminal artery (PTA) is the most common remnant of the primitive carotid-vertebrobasilar anastomoses, which typically form and obliterate during the early stages of human embryonic development. While PTA can be non-pathologic and is usually an incidental finding, it is also associated with various other vascular abnormalities, such as arteriovenous malformations and fistulae, but most commonly cerebral aneurysms. In these cases, aneurysms are usually reported in the anterior cerebral circulation or in the PTA trunk itself; to date, only one report exists of an associated aneurysm in the posterior circulation (basilar artery). These associated vascular pathologies are not only a source of morbidity and mortality but can also complicate subsequent endovascular treatment due to different flow patterns and increased vessel tortuosity. In this case report, we present the first reported case of PTA-associated aneurysm in the anterior inferior cerebellar artery and its resulting impact on the endovascular treatment of this aneurysm.

The FDA Reclassification of Cervical Pedicle and Lateral Mass Screws: A Case Study in Regulatory History.

The classification of medical devices by the Food and Drug Administration (FDA) involves rigorous scrutiny from specialized panels that designate devices as Class I, II, or III depending on their levels of relative risk to patient health. Posterior rigid pedicle screw systems were first classified by the FDA in 1984 and have since revolutionized the treatment of many spine pathologies. Despite this early classification by the FDA, posterior cervical pedicle and lateral mass screws were not reclassified from unclassified to Class III and then to Class II until 2019, nearly 35 years after their initial classification. This reclassification process involved a decades-long interplay between the FDA, formal panels, manufacturers, academic leaders, practicing physicians, and patients. It was delayed by lawsuits and a paucity of data demonstrating the ability to improve outcomes for cervical spinal pathologies. The off-label use of thoracolumbar pedicle screw rigid fixation systems by early adopters assisted manufacturers and professional organizations in providing the necessary data for the reclassification process. This case study highlights the collaboration between physicians and professional organizations in facilitating FDA reclassification and underscores changes to the current classification process that could avoid the prolonged dichotomy between common medical practice and FDA guidelines.

Comparison of Staged vs Same-Day Circumferential Spinal Fusions for Adult Spinal Deformity.

BACKGROUND: Patients often undergo circumferential (anterior and posterior) spinal fusions to maximize adult spinal deformity (ASD) correction and achieve adequate fusion. Currently, such procedures are performed in staged (ST) or same-day (SD) procedures with limited evidence to support either strategy. This study aims to compare perioperative outcomes and costs of ST vs SD circumferential ASD corrective surgeries. METHODS: This is a retrospective review of patients undergoing circumferential ASD surgeries between 2013 and 2018 in a single institution. Patient characteristics, preoperative comorbidities, surgical details, perioperative complications, readmissions, total hospital admission costs, and 90-day postoperative care costs were identified. All variables were tested for differences between ST and SD groups unadjusted and after applying inverse probability weighting (IPW), and the results before and after IPW were compared. RESULTS: The entire cohort included a total of 211 (ST = 50, SD = 161) patients, 100 of whom (ST = 44, SD = 56) underwent more than 4 levels fused posteriorly and anterior lumbar interbody fusion (ALIF). Although patient characteristics and comorbidities were not dissimilar between the ST and SD groups, both the number of levels fused in ALIF and posterior spinal fusion (PSF) were significantly different. Thus, using IPW, we were able to minimize the cohort incongruities in the number of levels fused in ALIF and PSF while maintaining comparable patient characteristics. In both the whole cohort and the long segment fusions, postoperative pulmonary embolism was more common in ST procedures. After adjustment utilizing IPW, both groups were not significantly different in disposition, 30-day readmissions, and reoperations. However, within the whole cohort and the long segment fusion cohort, the ST group continued to show significantly increased rates of pulmonary embolism, longer length of stay, and higher hospital admission costs compared with the SD group. CONCLUSIONS: Adjusted comparisons between ST and SD groups showed staging associated with significantly increased length of stay, risk of pulmonary embolism, and admission costs.

A Randomized Controlled Trial to Assess the Impact of Enhanced Recovery After Surgery on Patients Undergoing Elective Spine Surgery.

OBJECTIVE: To conduct a prospective, randomized controlled trial (RCT) of an enhanced recovery after surgery (ERAS) protocol in an elective spine surgery population. BACKGROUND: Surgical outcomes such as length of stay (LOS), discharge disposition, and opioid utilization greatly contribute to patient satisfaction and societal healthcare costs. ERAS protocols are multimodal, patient-centered care pathways shown to reduce postoperative opioid use, reduced LOS, and improved ambulation; however, prospective ERAS data are limited in spine surgery. METHODS: This single-center, institutional review board-approved, prospective RCT-enrolled adult patients undergoing elective spine surgery between March 2019 and October 2020. Primary outcomes were perioperative and 1-month postoperative opioid use. Patients were randomized to ERAS (n=142) or standard-of-care (SOC; n=142) based on power analyses to detect a difference in postoperative opioid use. RESULTS: Opioid use during hospitalization and the first postoperative month was not significantly different between groups (ERAS 112.2 vs SOC 117.6 morphine milligram equivalent, P =0.76; ERAS 38.7% vs SOC 39.4%, P =1.00, respectively). However, patients randomized to ERAS were less likely to use opioids at 6 months postoperatively (ERAS 11.4% vs SOC 20.6%, P =0.046) and more likely to be discharged to home after surgery (ERAS 91.5% vs SOC 81.0%, P =0.015). CONCLUSION: Here, we present a novel ERAS prospective RCT in the elective spine surgery population. Although we do not detect a difference in the primary outcome of short-term opioid use, we observe significantly reduced opioid use at 6-month follow-up as well as an increased likelihood of home disposition after surgery in the ERAS group.

Preoperative Predictors of Survival in Patients With Spinal Metastatic Disease.

BACKGROUND: There remains a number of factors thought to be associated with survival in spinal metastatic disease, but evidence of these associations is lacking. In this study, we examined factors associated with survival among patients undergoing surgery for spinal metastatic disease. METHODS: We retrospectively examined 104 patients who underwent surgery for spinal metastatic disease at an academic medical center. Of those patients, 33 received local preoperative radiation (PR) and 71 had no PR (NPR). Disease-related variables and surrogate markers of preoperative health were identified, including age, pathology, timing of radiation and chemotherapy, mechanical instability by spine instability neoplastic score, American Society of Anesthesiologists (ASA) classification, Karnofsky performance status (KPS), and body mass index (BMI). We performed survival analyses using a combination of univariate and multivariate Cox proportional hazards models to assess significant predictors of time to death. RESULTS: Local PR (Hazard Ratio [HR] = 1.84, P = 0.034), mechanical instability (HR = 1.11, P = 0.024), and melanoma (HR = 3.60, P = 0.010) were significant predictors of survival on multivariate analysis when controlling for confounders. PR vs NPR cohorts exhibited no statistically significant differences in preoperative age (P = 0.22), KPS (P = 0.29), BMI (P = 0.28), or ASA classification (P = 0.12). NPR patients had more reoperations for postoperative wound complications (11.3% vs 0%, P < 0.001). CONCLUSIONS: In this small sample, PR and mechanical instability were significant predictors of postoperative survival, independent of age, BMI, ASA classification, and KPS and in spite of fewer wound complications in the PR group. It is possible that PR was a surrogate of more advanced disease or poor response to systemic therapy, independently portending a worse prognosis. Future studies in larger, more diverse populations are crucial for understanding the relationship between PR and postoperative outcomes to determine the optimal timing for surgical intervention. CLINICAL RELEVANCE: These findings are clinically relevent as they provide insight into factors associated with survival in metastatic spinal disease.

A Prospective Cohort Study of Radiation Exposure to a Spine Surgeon's Exposed Body Parts During Utilization of Intraoperative Radiation-based Imaging.

STUDY DESIGN: Prospective cohort study. SUMMARY OF BACKGROUND DATA: C-arm fluoroscopy and O-arm navigation are vital tools in modern spine surgeries, but their repeated usage can endanger spine surgeons. Although a surgeon's chest and abdomen are protected by lead aprons, the eyes and extremities generally receive less protection. OBJECTIVE: In this study, we compare differences in intraoperative radiation exposure across the protected and unprotected regions of a surgeon's body. METHODS: Sixty-five consecutive spine surgeries were performed by a single spine-focused neurosurgeon over 9 months. Radiation exposure to the primary surgeon was measured through dosimeters worn over the lead apron, under the lead apron, on surgical loupes, and as a ring on the dominant hand. Differences were assessed with rigorous statistical testing and radiation exposure per surgical case was extrapolated. RESULTS: During the study, the measured radiation exposure over the apron, 176 mrem, was significantly greater than that under the apron, 8 mrem (P = 0.0020), demonstrating a shielding protective effect. The surgeon's dominant hand was exposed to 329 mrem whereas the eyes were exposed to 152.5 mrem of radiation. Compared with the surgeon's protected abdominal area, the hands (P = 0.0002) and eyes (P = 0.0002) received significantly greater exposure. Calculated exposure per case was 2.8 mrem for the eyes and 5.1 mrem for the hands. It was determined that a spine-focused neurosurgeon operating 400 cases annually will incur a radiation exposure of 60,750 mrem to the hands and 33,900 mrem to the eyes over a 30-year career. CONCLUSIONS: Our study found that spine surgeons encounter significantly more radiation exposure to the eyes and the extremities compared with protected body regions. Lifetime exposure exceeds the annual limits set by the International Commission on Radiologic Protection for the extremities (50,000 mrem/y) and the eyes (15,000 mrem/y), calling for increased awareness about the dangerous levels of radiation exposure that a spine surgeon incurs over one's career.

Should patients with lumbar stenosis and grade I spondylolisthesis be treated differently based on spinopelvic alignment? A retrospective, two-year, propensity matched, comparison of patient-reported outcome measures and clinical outcomes from multiple sites within a single health system.

BACKGROUND: Degenerative lumbar spondylolisthesis is one of the most common pathologies addressed by surgeons. Recently, data demonstrated improved outcomes with fusion in conjunction with laminectomy compared to laminectomy alone. However, given not all degenerative spondylolistheses are clinically comparable, the best treatment option may depend on multiple parameters. Specifically, the impact of spinopelvic alignment on patient reported and clinical outcomes following fusion versus decompression for grade I spondylolisthesis has yet to be explored. PURPOSE: This study assessed two-year clinical outcomes and one-year patient reported outcomes following laminectomy with concomitant fusion versus laminectomy alone for management of grade I degenerative spondylolisthesis and stenosis. The present study is the first to examine the effect of spinopelvic alignment on patient-reported and clinical outcomes following decompression alone versus decompression with fusion. STUDY DESIGN/SETTING: Retrospective sub-group analysis of observational, prospectively collected cohort study. PATIENT SAMPLE: 679 patients treated with laminectomy with fusion or laminectomy alone for grade I degenerative spondylolisthesis and comorbid spinal stenosis performed by orthopaedic and neurosurgeons at three medical centers affiliated with a single, tertiary care center. OUTCOME MEASURES: The primary outcome was the change in Patient-Reported Outcome Measurement Information System (PROMIS), Global Physical Health (GPH), and Global Mental Health (GMH) scores at baseline and post-operatively at 4-6 and 10-12 months postoperatively. Secondary outcomes included operative parameters (estimated blood loss and operative time), and two-year clinical outcomes including reoperations, duration of postoperative physical therapy, and discharge disposition. METHODS: Radiographs/MRIs assessed stenosis, spondylolisthesis, pelvic incidence, lumbar lordosis, sacral slope, and pelvic tilt; from this data, two cohorts were created based on pelvic incidence minus lumbar lordosis (PILL), denoted as "high" and "low" mismatch. Patients underwent either decompression or decompression with fusion; propensity score matching (PSM) and coarsened exact matching (CEM) were used to create matched cohorts of "cases" (fusion) and "controls" (decompression). Binary comparisons used McNemar test; continuous outcomes used Wilcoxon rank-sum test. Between-group comparisons of changes in PROMIS GPH and GMH scores were analyzed using mixed-effects models; analyses were conducted separately for patients with high and low pelvic incidence-lumbar lordosis (PILL) mismatch. RESULTS: 49.9% of patients (339) underwent lumbar decompression with fusion, while 50.1% (340) received decompression. In the high PLL mismatch cohort at 10-12 months postoperatively, fusion-treated patients reported improved PROs, including GMH (26.61 vs. 20.75, p<0.0001) and GPH (23.61 vs. 18.13, p<0.0001). They also required fewer months of outpatient physical therapy (1.61 vs. 3.65, p<0.0001) and had lower 2-year reoperation rates (12.63% vs. 17.89%, p=0.0442) compared to decompression-only patients. In contrast, in the low PLL mismatch cohort, fusion-treated patients demonstrated worse endpoint PROs (GMH: 18.67 vs. 21.52, p<0.0001; GPH: 16.08 vs. 20.74, p<0.0001). They were also more likely to require skilled nursing/rehabilitation centers (6.86% vs. 0.98%, p=0.0412) and extended outpatient physical therapy (2.47 vs. 1.34 months, p<0.0001) and had higher 2-year reoperation rates (25.49% vs. 14.71%,p=0.0152). CONCLUSIONS: Lumbar laminectomy with fusion was superior to laminectomy in health-related quality of life and reoperation rate at two years postoperatively only for patients with sagittal malalignment, represented by high PILL mismatch. In contrast, the addition of fusion for patients with low-grade spondylolisthesis, spinal stenosis, and spinopelvic harmony (low PILL mismatch) resulted in worse quality of life outcomes and reoperation rates.

Incidental Durotomy Repair in Lumbar Spine Surgery: Institutional Experience and Review of Literature.

STUDY DESIGN: : Retrospective Chart Review. OBJECTIVES: Incidental durotomies (IDs) are common spine surgery complications. In this study, we present a review on the most commonly utilized management strategies, report our institutional experience with case examples, and describe a stepwise management algorithm. METHODS: A retrospective review was performed of the electronic medical records of all patients who underwent a thoracolumbar or lumbar spine surgery between March 2017 and September 2019. Additionally, a literature review of the current management approaches to treat IDs and persistent postoperative CSF leaks following lumbar spine surgeries was performed. RESULTS: We looked at 1133 patients that underwent posterior thoracolumbar spine surgery. There was intraoperative evidence of ID in 116 cases. Based on our cohort and the current literature, we developed a progressive treatment algorithm for IDs that begins with a primary repair, which can be bolstered by dural sealants or a muscle patch. If this fails, the primary repair can be followed by a paraspinal muscle flap, as well as a lumbar drain. If the patient cannot be weaned from temporary CSF diversion, the final step in controlling postoperative leak is longterm CSF diversion via a lumboperitoneal shunt. In our experience, these shunts can be weaned once the patient has no further clinical or radiographic signs of CSF leak. CONCLUSIONS: There is no standardized management approach of IDs and CSF leaks in the literature. This article intends to provide a progressive treatment algorithm and contribute to the development process of a treatment consensus.

The Differences Between Same-Day and Staged (Circumferential) Fusion Surgery in Adult Spinal Deformity: Protocol for a Systematic Review.

BACKGROUND: Adult spinal deformity (ASD) is a deformity in the curvature of the adult spine. ASD includes a range of pathology that leads to decreased quality of life for patients as well as debilitating morbidities. Treatment can range from nonoperative management to long-segment surgical corrections and depends greatly on the deformity and patient profiles. If surgical treatment is indicated, circumferential (a combined anterior and posterior approach) fusion is one of the tools in the spine surgeon's armamentarium. Depending on the complexity, the procedure is either completed on the same day or staged. Determining whether to perform a circumferential surgery in a staged fashion is based largely on the surgeon's preference and perception of the individual case complexity; at present, there is no high-quality evidence that can be used to support that decision. OBJECTIVE: This paper presents the protocol for a systematic review that aims to investigate the differences between same-day versus staged circumferential fusion surgery in ASD both in patient selection and in outcomes. METHODS: Searches will be performed on MEDLINE, Embase, the Cochrane Central Register of Controlled Trials, Web of Science, and Scopus. Gray literature and the reference lists of articles included in the full-text screening will also be screened for inclusion. Results will be exported to Covidence. Data will be collected on demographics, type of procedures performed, surgery levels, blood loss, total operation time, length of stay, disposition, readmissions (30 days and 90 days), and perioperative complications. Patient-reported outcomes will also be assessed. Data quality assessment of randomized controlled trials will be performed using the Cochrane Collaboration's tool for assessing risk of bias in randomized trials, and nonrandomized studies will be assessed with the ROBINS-I (Risk of Bias in Non-randomized Studies of Interventions) tool. All screening, quality assessment, and data extraction will be done by 2 independent reviewers. A descriptive synthesis will be performed, and data will be evaluated for further analysis. RESULTS: This study is currently in the screening phase. There are no results yet. The search strategy has been developed and documented. Information has been exported to Covidence. Upon conclusion of the critical appraisal stage, screening and extraction, as well as a synthesis of the results, will be performed. CONCLUSIONS: The intended review will summarize the differences in perioperative outcomes and complications between same-day and staged (circumferential) fusion surgery in adult spinal deformity. It will also describe the patients selected for such procedures based on their demographics and pathology. Identified gaps in knowledge will provide insight into current limitations and guide further studies on this topic. TRIAL REGISTRATION: PROSPERO CRD42022339764; https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=339764. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): PRR1-10.2196/42331.

A hidden infection: Racemose neurocysticercosis causing hydrocephalus; a case report.

INTRODUCTION AND IMPORTANCE: Neurocysticercosis (NCC) is the most common helminthic central nervous system infection (CNS) in the Western hemisphere and the most common cause of acquired epilepsy worldwide. Due to its relatively prolonged latent period and clinical similarity to other infectious diseases - including bacterial or viral meningitis and other helminthic infections - NCC may be difficult to diagnose, especially for clinicians who rarely encounter it. CASE PRESENTATION: This case report discusses a patient with obstructive hydrocephalus and eosinophilic meningitis secondary to racemose NCC. The diagnosis process was initially complicated by the patient's history of pork allergy and absence of radiographic evidence of helminthic CNS infection. Further investigation showed a 4th ventricle multi-cystic lesion causing hydrocephalus which prompted a surgical intervention with a ventriculoperitoneal shunt (VPS) in conjunction with anti-helminthic medical treatment. At 1-year follow-up, the patient has reported recurrence of VPS related complications. CLINICAL DISCUSSION: Larval cysts typically deposit within the brain parenchyma, making them easily detected on head computed tomography (CT) scans and leading to neurologic sequelae such as epilepsy. In this case, the absence of CT evidence of NCC and the patient's lifelong history of pork allergy slowed the diagnosis process. CONCLUSION: Racemose NCC is a rare subset of the disease in which cyst clusters occupy the extra parenchymal space, thereby changing the symptomatic profile and making the cysts more difficult to visualize in imaging studies. In this case, magnetic resonance imaging (MRI) was the best imaging modality to diagnosis extra parenchymal NCC and guide its surgical management.

Etiologies, incidence, and demographics of lumbar vertebral fractures in U.S. emergency departments.

Background: Lumbar vertebral fractures are debilitating injuries widely associated with significant patient deformity, disability, pain, and potentially neurological deficit. This cross-sectional database study investigates the most frequent annual etiologies of lumbar vertebral fractures presented to emergency departments throughout the United States (U.S.) from 2010-2018. Methods: The National Electronic Injury Surveillance System (NEISS) database was used to identify all patients who visited participating emergency departments between 2010-2018 and were diagnosed with a lumbar spine fracture. Population estimates by age (18+) were obtained from annual U.S. Census estimates and used to calculate annual incidence rates of lumbar fractures per 100,000 people. Results: The annual incidence rate of total lumbar fractures in the U.S. increased from 14.6 to 22.5 per 100,000 people from 2010-2018 (54%). From 2010-2018, there were 382,914 [95% confidence interval (CI): 382,855-382,973] lumbar fractures in the U.S. This increased from 34,328 (95% CI: 34,277-34,379) in 2010 to 57,098 (95% CI: 57,044-57,152) in 2018 (66.3%). Men composed 40.2% and women made up 59.8% of patients. Mean patient age increased by 2.96 years from 65.5 (95% CI: 65.38-65.62) years in 2010 to 68.4 (95% CI: 68.32-68.48) years in 2018 (4.5%). From 2010-2018, floors, stairs/steps, and ladders were the most common etiologies of lumbar fractures. Estimated sum of floor-related fractures was 80,054 (95% CI: 79,986-80,122), stair/step-related fractures was 48,274 (95% CI: 48,209-48,339), and ladder-related fractures was 31,053 (95% CI: 30,987-31,119). The increase in these three etiologies accounted for 48% of the total increase of all-cause lumbar fractures between 2010 and 2018. Conclusions: The volume of lumbar vertebral fracture has increased over the last near decade (66.3%), and approximately half (48%) of these fractures can be attributed to accidents caused by flooring, stairs/steps, and ladder-related injuries. The increasing mean patient age, as well as accidents involving ladders, were found to be statistically correlated with the rise in total lumbar fracture volume.

Robot-assisted ventral sacral Tarlov cystectomy; A case report.

INTRODUCTION AND IMPORTANCE: Although asymptomatic Tarlov cysts (TCs) are reported in up to 13% of the population, symptomatic TCs are rare (less than 1%), making the management of the symptomatic cysts controversial. The most common location of symptomatic TCs is sacral nerve roots where they can cause pelvic, perineal chronic discomfort and pain, and lower extremity sensory and motor changes. Ventral (intrapelvic retroperitoneal) sacral TCs are extremely rare with no management recommendations. Available surgical options include cyst resection, and inlet-obliteration, however, these methods are often considered invasive and not definitive. CASE PRESENTATION: A 39-year-old woman presented with debilitating low back pain (LBP) radiating to her pelvis and the right lower extremity for 4 years. Magnetic Resonance Imaging (MRI) showed multiple sacral nerve root TCs including a large retroperitoneal right S3 TC. Surgical resection of the right S3 cyst was achieved utilizing a robot-assisted anterior approach which provided excellent visualization and maneuverability in the targeted retroperitoneal space. Postoperatively, the patient experienced significant pain relief, and she was able to perform activities of daily life and return to work. CLINICAL DISCUSSION: Robotic-assisted pelvic surgery has gained widespread popularity in the last two decades due to its many potential benefits. Utilizing robotic systems in sacral nerve sheath lesions shows a promise to deliver effective minimally invasive surgical management without sacrificing good visualization or instrument maneuverability. CONCLUSION: Robot-assisted resection of sacral nerve roots TCs represents a minimally invasive and safe surgical option to manage cysts located anterior to the sacrum in the pelvic retroperitoneal space.

Implantation of Engineered Axon Tracts to Bridge Spinal Cord Injury Beyond the Glial Scar in Rats.

Regeneration after spinal cord injury (SCI) is limited by the presence of a glial scar and inhibitory cell signaling pathways that favor scar formation over regrowth of endogenous neurons. Tissue engineering techniques, including the use of allografted neural networks, have shown promise for nervous system repair in prior studies. Through the use of a minimally invasive injury model in rats, we describe the implantation of micro-tissue engineered neural networks (micro-TENNs) across a region of SCI, spanning the glial scar to promote axonal regeneration. Forty-three female Sprague-Dawley rats were included in this study. Micro-TENNs were preformed in vitro before implant, and comprised rat sensory dorsal root ganglion (DRG) neurons projecting long bundled axonal tracts within the lumen of a biocompatible hydrogel columnar encasement (1.2 cm long; 701 µm outer diameter × 300 µm inner diameter). Animals were injured using a 2F embolectomy catheter inflated within the epidural space. After a 2-week recovery period, micro-TENNs were stereotactically implanted across the injury. Animals were euthanized at 1 week and 1 month after implantation, and the tissue was interrogated for the survival of graft DRG neurons and outgrowth of axons. No intraoperative deaths were noted with implantation of the micro-TENNs to span the injury cavity. Graft DRG axons were found to survive at 1 week postimplant within the hydrogel encasement. Graft-derived axonal outgrowth was observed within the spinal cord up to 4.5 mm from the implant site at 1 month postinjury. Limited astroglial response was noted within the host, suggesting minimal trauma and scar formation in response to the graft. Micro-TENN sensory neurons survive and extend axons into the host spinal cord following a minimally invasive SCI in rats. This work serves as the foundation for future studies investigating the use of micro-TENNs as a living bridge to promote recovery following SCI. Impact statement As spinal cord injury pathology develops, the establishment of a glial scar puts an end to the hope of regeneration and recovery from the consequent neurological deficits. Therefore, growing attention is given to bioengineered scaffolds that can bridge the lesions bordered by this scar tissue. The utilization of longitudinally aligned preformed neural networks-referred to as micro-tissue engineered neural networks (TENNs)-presents a promising opportunity to provide a multipurpose bridging strategy that may take advantage of several potential mechanisms of host regeneration. In addition to providing physical support for regenerating spinal cord axons, micro-TENNs may serve as a functional "cable" that restores lost connections within the spinal cord.

Postoperative Sagittal Spinal Alignment Changes Following Corrective Surgery in Adult Spinal Deformity.

BACKGROUND: There is a paucity of literature covering the spinal alignment changes following adult spinal deformities (ASD) corrective surgeries. In theory, patients' posture and overall alignment may vary with postoperative pain, bracing, and other external variables requiring further radiographic follow-up. The purpose of the study is to investigate changes in sagittal alignment in the first 3 months postoperatively. METHODS: This is a retrospective case series of ASD patients who underwent deformity surgeries from October 2015 to June 2018. Patients < 40 years old, had < 6 levels fused, had acute proximal junctional kyphosis (PJK) or failure, or lacked imaging were excluded. Physiologic measures, spine alignment changes measured in whole-spine radiographs. Lumbar lordosis (LL), thoracic kyphosis (TK), and sagittal vertical axis (SVA) at immediate and 3-month postoperative time points were measured, then compared via 2-sample Student t tests. Furthermore, TK after upper thoracic to pelvis (UT-P) fusions was compared with lower thoracic to pelvis (LT-P) fusions via paired t test. RESULTS: Thirty-six patients (24 females, 67%) with a mean age of 61.5 years (range, 40-75 years) were included. Spinal alignment comparisons showed a significant increase in TK at the 3-month time point (P = 0.006). Additionally, wide variations in SVA (range, 47-144 mm) were noted, yet not statistically significant, likely due to the changes being in both positive and negative directions (P = 0.18). No significant difference was found when TK was compared in the UT-P vs LT-P groups. CONCLUSIONS: Our results suggest that as postoperative pain subsides and the body settles into its new alignment, significant changes occur in spine sagittal parameters in the subacute period following surgery. LEVEL OF EVIDENCE: 4.

Candidates for Percutaneous Screw Fixation Without Fusion in Thoracolumbar Fractures: A Retrospective Matched Cohort Study.

STUDY DESIGN: Retrospective matched cohort study. OBJECTIVES: Identifying candidates for isolated percutaneous screw fixation (PSF) in thoracolumbar fractures based on Thoracolumbar Injury Classification and Severity (TLICS) score. METHODS: Patients underwent PSF were split into 3 TLICS-score categories, then matched with groups having similar scores managed either non-operatively or via open screw fixation (OSF). Each category was assessed for corrective power and loss of correction by comparing initial and 1-year Cobb angles as well as Oswestry Disability Index and rates of fracture healing at 1 year. RESULTS: A total of 102 patients (40 females) with age range 19 to 51 years, were admitted 1 to 25 hours following trauma. Each of TLISC categories consisted of matched treatment groups for comparison. In TLICS-3 fractures (2 treatment groups, n = 12 each), PSF showed similar outcomes but longer time to ambulation and length of stay (LOS) compared with nonoperative management. In TLICS-4 fractures (3 treatment groups, n = 18 each), PSF showed comparable corrective power and outcomes as OSF but was better in terms of operative time, blood loss, time to ambulation, LOS, and cosmesis. Despite higher LOS when compared with nonoperative cases, PSF showed superior radiologic and functional outcomes. In TLICS-5 fractures (2 treatment groups, n = 12 each), PSF showed shorter admissions and time to ambulation but lower corrective power, functional recovery, and tendency to lower healing rates. CONCLUSIONS: Isolated PSF is a valid choice in managing TLICS-4 thoracolumbar fractures; however, it did not surpass conventional methods in TLICS-3 or TLICS-5 fracture types. Further studies are needed before the generalization of findings.

Association of spinal instability due to metastatic disease with increased mortality and a proposed clinical pathway for treatment.

OBJECTIVE: Multidisciplinary treatment including medical oncology, radiation oncology, and surgical consultation is necessary to provide comprehensive therapy for patients with spinal metastases. The goal of this study was to review the use of radiation therapy and/or surgical intervention and their impact on patient outcomes. METHODS: In this retrospective series, the authors identified at their institution those patients with spinal metastases who had received radiation therapy alone or had undergone surgery with or without radiation therapy within a 6-year period. Data on patient age, chemotherapy, surgical procedure, radiation therapy, Karnofsky Performance Status (KPS), primary tumor pathology, Spinal Instability Neoplastic Score (SINS), and survival after treatment were collected from the patient electronic medical records. N - 1 chi-square testing was used for comparisons of proportions. The Student t-test was used for comparisons of means. A p value < 0.05 was considered statistically significant. A survival analysis was completed using a multivariate Cox proportional hazards model. RESULTS: Two hundred thirty patients with spinal metastases were identified, 109 of whom had undergone surgery with or without radiation therapy. Among the 104 patients for whom the surgical details were reviewed, 34 (33%) had a history of preoperative radiation to the surgical site but ultimately required surgical intervention. In this surgical group, a significantly increased frequency of death within 30 days was noted for the SINS unstable patients (23.5%) as compared to that for the SINS stable patients (2.3%; p < 0.001). The SINS was a significant predictor of time to death among surgical patients (HR 1.11, p = 0.037). Preoperative KPS was not independently associated with decreased survival (p > 0.5) on univariate analysis. One hundred twenty-six patients met the criteria for inclusion in the radiation-only analysis. Ninety-eight of these patients (78%) met the criteria for potential instability (PI) at the time of treatment, according to the SINS system. Five patients (5%) with PI in the radiation therapy group had a documented neurosurgical or orthopedic surgery consultation prior to radiation therapy. CONCLUSIONS: At the authors' institution, patients with gross mechanical instability per the SINS system had an increased rate of 30-day postoperative mortality, which remained significant when controlling for other factors. Surgical consultation for metastatic spine patients receiving radiation oncology consultation with PI is low. The authors describe an institutional pathway to encourage multidisciplinary treatment from the initial encounter in the emergency department to expedite surgical evaluation and collaboration.

Dorsal root ganglion axons facilitate and guide cortical neural outgrowth: In vitro modeling of spinal cord injury axonal regeneration.

BACKGROUND: Spinal cord injury (SCI) patients represent a heterogeneous group, with injuries ranging from partial compression to complete transection. Patients with complete injuries are unlikely to exhibit recovery and suffer from paralysis as well as the loss of bowel and bladder function. One treatment option is the formation of a bridge through a lesion site, whereby transplanted cells or biocompatible scaffolds guide the regenerating axons across the site of injury. Moreover, the viability of transplanted dorsal root ganglia (DRGs) into rat spinal cord has been previously demonstrated. OBJECTIVE: We aim to demonstrate the feasibility of using DRG axons as a bridging tool to help guide the axonal growth of cortical neurons. METHODS: Cortical neurons were isolated from embryonic rats and two aggregated populations were cultured at increasing distances in isolation and in a co-culture with DRG explants. Growth rates of the sprouting axons and connections between the two populations were observed over a period of twelve days. RESULTS: DRG explants demonstrated the ability to grow robust axonal connections that can connect two explants separated by up to 10 mm, however, CNAs could not achieve connections in distances greater than 2 mm. The co-culture of CNAs with DRG explants facilitated axonal growth between two populations of CNAs at distances they cannot otherwise traverse. CONCLUSIONS: Our findings support the use of DRG axons to facilitate the growth of cortical neurons in a process of axon-facilitated axon regeneration. We believe these results could have implications for the treatment of SCI.

A Strategy Toward Bridging a Complete Spinal Cord Lesion Using Stretch-Grown Axons.

In this study, we evaluated the ability of stretch-grown tissue-engineered nerve grafts (TENGs) to perform as a living scaffold for axonal regeneration across a severed spinal cord lesion. TENGs, consisting of stretch-grown axons spanning two populations of dorsal root ganglia neurons, have proven to be effective in bridging gaps in peripheral nerve injury. A complete transection was performed at the thoracic level in a rodent model and 5 mm of cord was completely removed. TENGs encapsulated in a collagen hydrogel were placed within the cavity and compared against a collagen only transplant. Through hematoxylin and eosin (H&E) staining and immunohistochemistry, we found that TENGs survived up to 6 weeks post-transplant, extending neuronal processes into and through host tissue early on in both the rostral and caudal direction. In several cases, TENG axons penetrated into and through glial scar tissue, appearing to overcome a common obstacle for axonal regeneration in spinal cord injuries (SCIs). H&E staining also provided evidence that animals treated with TENGs resulted in lesion sites with greater tissue infiltration and less compression than animals treated with a collagen hydrogel only, an encouraging finding given the severity of the injury model. We also observed effects the TENGs had on glial scar formation, cyst formation, and immune response at multiple time points as these are common difficulties faced in tissue engineering methods to treat or repair SCI. If able to address these universal challenges associated with SCI, TENGs may offer an alternative option in neural transplantation and may represent a viable tool in the multifaceted treatment of SCI. Impact statement In complete spinal cord injury (SCI), a significant gap forms in the injury sites replacing the neural connections and limiting the link between healthy spinal cord distal to the injury and cerebral cortex. This study aims to demonstrate the potential benefit of hydrogel collagen constructs bearing stretch-grown dorsal root ganglion axons to bridge a complete injury gap, to restore the lost connections and forming a basic infrastructure to support the regrowth of new connection. This application of stretch-grown axons in neural implants offers hope to achieve a highly modifiable and resilient bridging strategy to treat SCI.

Risk of Vertebral Artery Injury and Stroke Following Blunt and Penetrating Cervical Spine Trauma: A Retrospective Review of 729 Patients.

BACKGROUND: Cervical spine trauma (CST) may result in vertebral artery injury (VAI), increasing the risk of developing stroke. Stroke risk following CST is poorly reported. METHODS: In total, 729 patients with CST were retrospectively analyzed, including rates of VAI, age at injury, cause of injury, cardiovascular history, smoking history, substance abuse history, embolization therapy, and antiplatelet or anticoagulant therapy prior or after injury. VAIs were identified and graded following the Modified Denver Criteria for Blunt Cerebrovascular Injury using magnetic resonance angiography and computed tomography angiography. Brain scans were reviewed for stroke rates and statistically significant variations. RESULTS: Thirty-three patients suffered penetrating trauma, whereas 696 patients experienced blunt trauma. In total, 81 patients met the criteria for analysis with confirmed VAI. VAI was more common in penetrating injury group compared with blunt injury group (64% vs. 9%, P < 0.0005). However, low-grade VAI (less than grade III) was more common in blunt injury group versus penetrating group (37% vs. 14%, P < 0.05). The frequency of posterior circulation strokes did not vary significantly between groups (26.3% vs. 13.8%, P = 0.21). Cardiovascular comorbidities were significantly more common in the blunt group (50%, P = 0.0001) compared with the penetrating group (0%). CONCLUSIONS: VAI occurs with a high incidence in penetrating CST. Although stroke risk following penetrating and blunt CST did not vary significantly, they resulted in serious complications in a group of patients. Further study of this patient population is required to provide high-level, evidence-based preventions for VAI complications.