Lumbar Endoscopic Unilateral Laminectomy for Bilateral Decompression in Degenerative Spondylolisthesis.

INTRODUCTION: Degenerative spondylolisthesis is an important cause of chronic low-back and radiculopathy in the adult US population. Open decompression with or without fusion is considered the standard for management, yet optimal treatment remains controversial. Full endoscopic spine surgery offers an alternative surgical approach with possible advantages. There is a paucity of data on the use of FESS in degenerative spondylolisthesis. Therefore, we present the clinical and radiographic outcomes of 73 patients with low-grade degenerative spondylolisthesis with severe stenosis, who underwent lumbar endoscopic unilateral laminectomy for bilateral decompression. METHODS: Patients with low-grade degenerative spondylolisthesis who underwent a lumbar endoscopic ULBD at six spine centers in North America were included in this study. Patients were followed up at 3, 9, and 12 months. Static and dynamic imaging was performed and evaluated routinely before surgery to identify the pathology and grade of spondylolisthesis. Patient reported outcomes were prospectively collected. RESULTS: This study included 73 patients from six spine centers. Sixty-two patients were diagnosed with grade 1 spondylolisthesis while 11 were diagnosed with grade 2 spondylolisthesis. Postoperatively 70 patients reported improved symptoms and pain resolution while three patients reported worse pain. Mean VAS back, VAS leg, and ODI scores showed a statistically significant improvement at 3, 9, and 12-months when compared to the preoperative period. Radiographically, no patient in our study had progression of grade of spondylolisthesis. CONCLUSION: Patients with low-grade degenerative spondylolisthesis causing severe stenosis can safely be treated with lumbar endoscopic unilateral laminectomy for bilateral decompression. Head-to-head trial should be undertaken to provide higher level of clinical evidence.

Ambulatory discharge of patients undergoing sleeve gastrectomy results in significantly more adverse outcomes.

BACKGROUND: Same-day discharge after sleeve gastrectomy (SDSG) has become more common during the COVID pandemic. Several payers have suggested that they would no longer reimburse for planned inpatient hospital stay for patients undergoing SG. The goal of our study was to determine which, if any, patient groups could safely undergo SDSG. METHODS: A retrospective analysis of the Metabolic and Bariatric Surgery Accreditation and Quality Improvement Project (MBSAQIP) from 2015-2021 was performed. Multivariable logistic regression analysis was performed using demographics, comorbid disease, and participant use data file (PUF) year to determine the risk of adverse events within 30 days of SG by postoperative discharge day. RESULTS: A total of 702,622 SGs were performed during the study period: 31,308 (4.46%) patients were SDSGs and 409,622 (58.3%) on postoperative day (POD) 1. From 2015 to 2019, the mean percentage of cases that were SDSG was 2.9%. The proportion of SDSG increased to 6.3% in 2020 and 9.6% in 2021. Compared with those discharged on POD 1, SDSG patients were at increased risk for any complication (OR 1.22, 95% CI 1.1-1.36), minor complications (OR 1.17, 95% CI 1.03-1.32), major complications (OR 1.36, 95% CI 1.15-1.61), readmission (OR 1.09, 95% CI 1.00-1.18), and reoperation (OR 1.37, 95% CI 1.16-1.62). Other interventions within 30 days were not statistically significant. CONCLUSION: Compared with those discharged on POD 1, SDSG patients are at significantly increased risk for all adverse events analyzed. With growing pressure to shorten or eliminate the use of hospital beds, identification of appropriate candidates for safe SDSG is crucial.

Core outcomes in nerve surgery: development of a core outcome set for common peroneal (fibular) neuropathy.

OBJECTIVE: Common peroneal (fibular) neuropathy is the most common mononeuropathy of the lower extremity. Despite this, there are surprisingly few studies on the topic, and a knowledge gap remains in the literature. As one attempts to address this knowledge gap, a core outcome set (COS) is needed to guide the planning phases of future studies to allow synthesis and comparability of these studies. The objective of this study was to develop the COS-common peroneal neuropathy (CoPe) using a modified Delphi approach. METHODS: A 5-stage approach was used to develop the COS-CoPe: 1) stage 1, consortium development; 2) stage 2, a literature review to identify potential outcome measures; 3) stage 3, a Delphi survey to develop consensus on outcomes for inclusion; 4) stage 4, a Delphi survey to develop definitions; and 5) stage 5, a consensus meeting to finalize COS and definitions. The study followed the COS-STAndards for Development (COS-STAD) recommendations. RESULTS: The Core Outcomes in Nerve Surgery (COINS) Consortium comprised 23 participants, all neurological surgeons, representing 13 countries. The final COS-CoPe consisted of 31 data points/outcomes covering domains of demographics, diagnostics, patient-reported outcomes, motor/sensory outcomes, and complications. Appropriate instruments, methods of testing, and definitions were set. The consensus minimum duration of follow-up was 12 months. The consensus optimal time points for assessment were preoperatively and 3, 6, 12, and 24 months postoperatively. CONCLUSIONS: The COINS Consortium developed a consensus COS and provided definitions, methods of implementation, and time points for assessment. The COS-CoPe should serve as a minimum set of data that should be collected in all future neurosurgical studies on common peroneal neuropathy. Incorporation of this COS should help improve consistency in reporting, data synthesis, and comparability, and should minimize outcome reporting bias.

Spinal cord metrics derived from diffusion MRI: improvement in prognostication in cervical spondylotic myelopathy compared with conventional MRI.

OBJECTIVE: A major shortcoming in optimizing care for patients with cervical spondylotic myelopathy (CSM) is the lack of robust quantitative imaging tools offered by conventional MRI. Advanced MRI modalities, such as diffusion MRI (dMRI), including diffusion tensor imaging (DTI) and diffusion basis spectrum imaging (DBSI), may help address this limitation by providing granular evaluations of spinal cord microstructure. METHODS: Forty-seven patients with CSM underwent comprehensive clinical assessments and dMRI, followed by DTI and DBSI modeling. Conventional MRI metrics included 10 total qualitative and quantitative assessments of spinal cord compression in both the sagittal and axial planes. The dMRI metrics included 12 unique measures including anisotropic tensors, reflecting axonal diffusion, and isotropic tensors, describing extraaxonal diffusion. The primary outcome was the modified Japanese Orthopaedic Association (mJOA) score measured at 2 years postoperatively. Extreme gradient boosting-supervised classification algorithms were used to classify patients into disease groups and to prognosticate surgical outcomes at 2-year follow-up. RESULTS: Forty-seven patients with CSM, including 24 (51%) with a mild mJOA score, 12 (26%) with a moderate mJOA score, and 11 (23%) with a severe mJOA score, as well as 21 control subjects were included. In the classification task, the traditional MRI metrics correctly assigned patients to healthy control versus mild CSM versus moderate/severe CSM cohorts, with an accuracy of 0.647 (95% CI 0.64-0.65). In comparison, the DTI model performed with an accuracy of 0.52 (95% CI 0.51-0.52) and the DBSI model's accuracy was 0.81 (95% CI 0.808-0.814). In the prognostication task, the traditional MRI metrics correctly predicted patients with CSM who improved at 2-year follow-up on the basis of change in mJOA, with an accuracy of 0.58 (95% CI 0.57-0.58). In comparison, the DTI model performed with an accuracy of 0.62 (95% CI 0.61-0.62) and the DBSI model had an accuracy of 0.72 (95% CI 0.718-0.73). CONCLUSIONS: Conventional MRI is a powerful tool to assess structural abnormality in CSM but is inherently limited in its ability to characterize spinal cord tissue injury. The results of this study demonstrate that advanced imaging techniques, namely DBSI-derived metrics from dMRI, provide granular assessments of spinal cord microstructure that can offer better diagnostic and prognostic utility.

Percutaneous Screw Distraction for Anatomic Restoration: Case Series.

BACKGROUND AND OBJECTIVES: Percutaneous pedicle screw fixation with distraction reduces morbidity after traumatic thoracolumbar burst fractures; however, there are substantial limitations, particularly for correction of kyphosis. The use of fixed-angle screws may offer improved anatomic restoration, facilitating greater postdistraction vertebral height restoration and spinal canal fragment reduction. We examined the radiographic results of distraction across fixed-angle screws immediately after surgery and in long-term follow-up. METHODS: Demographic and clinical characteristics were captured for patients with traumatic thoracolumbar fractures undergoing percutaneous pedicle screw fixation by a single surgeon. Radiographic measurements were collected at predistraction, postdistraction, and long-term follow-up time points. Paired t-tests, Student's t-tests, Mann-Whitney U tests, and χ2 tests were used to assess data where appropriate. RESULTS: The case series included 22 patients (77.3% male; mean age 42.0 ± 18.4 years). Hounsfield density consistent with osteopenia was seen in 13.6% of patients at the time of injury. Sporting injuries and motor vehicle accidents were common (both 31.8%). Most injuries occurred at L1 (45.5%). Upon long-term follow-up, the mean injured-level predistraction cross-sectional area improved from 2.1 to 2.9 cm2 (P < .01). Compared with the superadjacent level, the injured-level cross-sectional canal area improved by 28.6% (P < .01). Vertebral body index also improved significantly (18.8° mean change, P < .01). The mean bisegmental Cobb angle improved by 6.2° (P = .01), and injured vertebral body compression decreased by 22.4% (P < .01). Significant improvement in correction was achieved with experience, with final technique yielding superior cross-sectional area (P = .04) and compression ratios (P = .03). CONCLUSION: Distraction across fixed-angle percutaneous screw instrumentation systems stabilizes traumatic thoracolumbar burst fractures, corrects deformity, and decompresses the spinal canal. Further comparative research is necessary to demonstrate whether outcomes are different between percutaneous instrumentation vs open fusion for thoracolumbar trauma.

Diffusion MRI Metrics Characterize Postoperative Clinical Outcomes After Surgery for Cervical Spondylotic Myelopathy.

BACKGROUND AND OBJECTIVES: Advanced diffusion-weighted MRI (DWI) modeling, such as diffusion tensor imaging (DTI) and diffusion basis spectrum imaging (DBSI), may help guide rehabilitation strategies after surgical decompression for cervical spondylotic myelopathy (CSM). Currently, however, postoperative DWI is difficult to interpret, owing to signal distortions from spinal instrumentation. Therefore, we examined the relationship between postoperative DTI/DBSI-extracted from the rostral C3 spinal level-and clinical outcome measures at 2-year follow-up after decompressive surgery for CSM. METHODS: Fifty patients with CSM underwent complete clinical and DWI evaluation-followed by DTI/DBSI analysis-at baseline and 2-year follow-up. Clinical outcomes included the modified Japanese Orthopedic Association score and comprehensive patient-reported outcomes. DTI metrics included apparent diffusion coefficient, fractional anisotropy, axial diffusivity, and radial diffusivity. DBSI metrics evaluated white matter tracts through fractional anisotropy, fiber fraction, axial diffusivity, and radial diffusivity as well as extra-axonal pathology through restricted and nonrestricted fraction. Cross-sectional Spearman's correlations were used to compare postoperative DTI/DBSI metrics with clinical outcomes. RESULTS: Twenty-seven patients with CSM, including 15, 7, and 5 with mild, moderate, and severe disease, respectively, possessed complete baseline and postoperative DWI scans. At 2-year follow-up, there were 10 significant correlations among postoperative DBSI metrics and postoperative clinical outcomes compared with 3 among postoperative DTI metrics. Of the 13 significant correlations, 7 involved the neck disability index (NDI). The strongest relationships were between DBSI axial diffusivity and NDI (r = 0.60, P < .001), DBSI fiber fraction and NDI (rs = -0.58, P < .001), and DBSI restricted fraction and NDI (rs = 0.56, P < .001). The weakest correlation was between DTI apparent diffusion coefficient and NDI (r = 0.35, P = .02). CONCLUSION: Quantitative measures of spinal cord microstructure after surgery correlate with postoperative neurofunctional status, quality of life, and pain/disability at 2 years after decompressive surgery for CSM. In particular, DBSI metrics may serve as meaningful biomarkers for postoperative disease severity for patients with CSM.

Examining emergency department utilization following bariatric surgery.

BACKGROUND: Emergency department (ED) utilization following surgery is poorly understood and places immense strain on the healthcare system, being responsible for up to $38 billion in wasteful spending annually. The aim of this study was to quantify ED utilization following bariatric procedures to identify causes and areas of improvement. MATERIALS AND METHODS: A retrospective review of a prospectively maintained database was conducted for all patients who underwent metabolic bariatric surgery (MBS) between November 2006 and June 2019. The study includes 4703 patients across 8 hospitals in a single health system. Patients who returned to the ED within 30 and 90 days were analyzed for relation to surgery and preventability. RESULTS: Of the 4703 patients that underwent MBS, 907 (19.3%) visited the ED at least once within 90 days and 350 (7.4%) required hospital readmission. The most common bariatric procedure performed was the Roux-en-Y Gastric Bypass (RYGB) (3716/4703) with an average BMI of 43.8. The median length between discharge and ED visit was 19 days. Under 50% of patients called prior to ED presentation and 61% of these ED visits resulted in discharge. CONCLUSION: While hospital readmissions following MBS have been scrutinized in literature, investigation of ED utilization remains scarce. Our study is one of few to investigate postoperative ED utilization up to 90 days following bariatric intervention. A clear opportunity exists to improve discharge education and early post-discharge communication. This would additionally alleviate burden to allow focus on the acutely ill.

Botulinum toxin injections for the treatment of neurogenic thoracic outlet syndrome: A systematic review.

Botulinum toxin (BTX) injections into the musculature surrounding the brachial plexus have been examined as a potential treatment for neurogenic thoracic outlet syndrome (nTOS). This systematic review identified 15 publications, of which one was a randomized controlled trial. BTX injections performed with ultrasound or electromyographic guidance, and with the inclusion of the pectoralis minor muscle, in addition to the anterior and/or middle scalenes, tended to provide greater symptom improvement and may predict response to first rib resection. Importantly, most studies were of low quality; thus, the results should be interpreted with caution. Further high-quality studies are needed to confirm these findings.

Core outcomes in nerve surgery: development of a core outcome set for brachial plexus and upper extremity nerve injuries.

OBJECTIVE: When considering traumatic brachial plexus and upper extremity nerve injuries, iatrogenic nerve injuries, and nontraumatic nerve injuries, brachial plexus and upper extremity nerve injuries are commonly encountered in clinical practice. Despite this, data synthesis and comparison of available studies are difficult. This is at least in part due to the lack of standardization in reporting and a lack of a core outcome set (COS). Thus, there is a need for a COS for adult brachial plexus and upper extremity nerve injuries (COS-BPUE). The objective of this study was to develop a COS-BPUE using a modified Delphi approach. METHODS: A 5-stage approach was used to develop the COS-BPUE: 1) consortium development, 2) literature review to identify potential outcome measures, 3) Delphi survey to develop consensus on outcomes for inclusion, 4) Delphi survey to develop definitions, and 5) consensus meeting to finalize the COS and definitions. The study followed the Core Outcome Set-STAndards for Development (COS-STAD) recommendations. RESULTS: The Core Outcomes in Nerve Surgery (COINS) Consortium comprised 23 participants, all neurological surgeons, representing 13 countries. The final COS-BPUE consisted of 36 data points/outcomes covering demographic, diagnostic, patient-reported outcome, motor/sensory outcome, and complication domains. Appropriate instruments, methods of testing, and definitions were set. The consensus minimum duration of follow-up was 24 months, with the consensus optimal time points for assessment being preoperatively and 3, 6, 12, and 24 months postoperatively. CONCLUSIONS: The COINS Consortium developed a consensus COS and provided definitions, methods of implementation, and time points for assessment. The COS-BPUE should serve as a minimum set of data that should be collected in all future neurosurgical studies on adult brachial plexus and upper extremity nerve injuries. Incorporation of this COS should help improve consistency in reporting, data synthesis, and comparability, and should minimize outcome reporting bias.

Exuberant circumferential fibroproliferative neuromas in lipomatosis of nerve: a unifying theory. Illustrative case.

BACKGROUND: Lipomatosis of nerve (LN) is a rare disorder characterized by the massive enlargement of peripheral nerves, frequently accompanied by generalized fibroadipose proliferation and skeletal overgrowth. OBSERVATIONS: The authors have been routinely following a 20-year-old male for lipomatosis of median nerve at the wrist noted shortly after birth. He had undergone resection of the lesion accompanied by sural nerve grafting at another institution. Clinically, although his neurological loss of function has been stable, he has had continued soft tissue growth. Serial magnetic resonance imaging has revealed persistent LN proximal to the repair sites with evidence of fatty proliferation in the sural grafts and continued LN and fatty proliferation distally. There has been a progressive circumferential pattern of fibrosis around the proximal and distal suture lines, which has a similar radiological pattern to desmoid type fibromatosis (a pattern recently described in neuromuscular choristoma [NMC] desmoid-type fibromatosis). LESSONS: Considering the similar reaction of nerve in both LN and NMC despite differing genetic cascades, the authors believe a unifying process occurs in both lesions. The pattern of circumferential fibroproliferation would be most consistent with neuron-mediated growth from unspecified trophic factors, supporting a previously reported a nerve-derived "inside-out mechanism." The clinical consequences of this unifying process are presented.

Exoscope for revision of right lateral femoral cutaneous nerve decompression.

The exoscope serves as a valuable addition or alternative to traditional microscope systems in surgery, offering 3D visualization and magnification with enhanced maneuverability. In lateral femoral cutaneous nerve decompression for meralgia paresthetica, the exoscope is effective in identifying strictures of neural compression and minimizing iatrogenic nerve damage that may lead to improved pain management outcomes for patients. In this report, the specific case presented showcases how the exoscope aided in surgical decompression of the lateral femoral cutaneous nerve of a patient with refractory meralgia paresthetica with remote previous decompression and resultant scarring. The video can be found here: https://stream.cadmore.media/r10.3171/2023.10.FOCVID23162.

Hospital cost differences between open and endoscopic lumbar spine decompression surgery.

OBJECTIVE: In recent years, fully endoscopic decompression surgery for degenerative spine disease has become increasingly popular in the US. Although an endoscopic approach has demonstrated some benefits compared with open procedures in randomized controlled trials, the cost of advanced technologies remains contested. The authors evaluated the differences in costs and cost drivers between open and endoscopic decompression surgical procedures performed at a single institution. METHODS: Using associated Current Procedural Terminology codes, the authors identified all open and endoscopic decompression lumbar surgical procedures performed from January 1, 2016, through December 31, 2022. Preoperative comorbidities, surgical characteristics, and postoperative outcomes were captured. The costs of index surgery-related readmission for revision, washout, or other complications were included in the index surgery expenses. Associated in-hospital costs were collected; these were reported in comparative percentages with open surgical procedures as the baseline because of an institutional agreement. Univariate and multivariate analyses were performed. RESULTS: The retrospective search identified 633 open surgical procedures and 195 endoscopic surgical procedures for inclusion. The two patient cohorts were similar, with clinically nonrelevant but statistically significant differences in mean age (open 55.7 years vs endoscopic 59.4 years, p = 0.01) and mean American Society of Anesthesiologists physical status class (open 2.3 vs endoscopic 2.4, p = 0.03). Postoperatively, patients who underwent open surgical procedures had significantly longer mean hospital stays (open 1.4 days vs endoscopic 0.7, p < 0.01) and more perioperative complications (open 7.9% of patients vs endoscopic 3.1%, p = 0.02), and they required washout surgical procedures in some cases (open 1.3% vs endoscopic 0%, p = 0.12). The largest cost difference between open and endoscopic surgical procedures was the significantly greater cost of disposable supplies for endoscopic cases (10.1% vs 31.7% of the total cost of open procedures, p < 0.01), and open surgical procedures were generally less costly in total (100.0% vs 115.1%, p < 0.01). In multivariate linear regression, endoscopic surgery was independently associated with greater total costs (standardized beta 15.9%, p < 0.01), although length of hospital stay (standardized beta 34.0%) and readmissions (standardized beta 30.0%, p < 0.01) had larger effects on cost. CONCLUSIONS: The endoscopic approach was associated with greater total in-hospital costs compared with open procedures. The findings of further cost evaluations, including those of patient-reported outcomes, social cost, and capital costs per procedure type, need to be included in operational and clinical decisions.

Impact of Upper Limb Motor Recovery on Functional Independence After Traumatic Low Cervical Spinal Cord Injury.

Cervical spinal cord injury (SCI) causes devastating loss of upper limb function and independence. Restoration of upper limb function can have a profound impact on independence and quality of life. In low-cervical SCI (level C5-C8), upper limb function can be restored via reinnervation strategies such as nerve transfer surgery. The translation of recovered upper limb motor function into functional independence in activities of daily living (ADLs), however, remains unknown in low cervical SCI (i.e., tetraplegia). The objective of this study was to evaluate the association of patterns in upper limb motor recovery with functional independence in ADLs. This will then inform prioritization of reinnervation strategies focused to maximize function in patients with tetraplegia. This retrospective study performed a secondary analysis of patients with low cervical (C5-C8) enrolled in the SCI Model Systems (SCIMS) database. Baseline neurological examinations and their association with functional independence in major ADLs-i.e., eating, bladder management, and transfers (bed/wheelchair/chair)-were evaluated. Motor functional recovery was defined as achieving motor strength, in modified research council (MRC) grade, of ≥ 3 /5 at one year from ≤ 2/5 at baseline. The association of motor function recovery with functional independence at one-year follow-up was compared in patients with recovered elbow flexion (C5), wrist extension (C6), elbow extension (C7), and finger flexion (C8). A multi-variable logistic regression analysis, adjusting for known factors influencing recovery after SCI, was performed to evaluate the impact of motor function at one year on a composite outcome of functional independence in major ADLs. Composite outcome was defined as functional independence measure score of 6 or higher (complete independence) in at least two domains among eating, bladder management, and transfers. Between 1992 and 2016, 1090 patients with low cervical SCI and complete neurological/functional measures were included. At baseline, 67% of patients had complete SCI and 33% had incomplete SCI. The majority of patients were dependent in eating, bladder management, and transfers. At one-year follow-up, the largest proportion of patients who recovered motor function in finger flexion (C8) and elbow extension (C7) gained independence in eating, bladder management, and transfers. In multi-variable analysis, patients who had recovered finger flexion (C8) or elbow extension (C7) had higher odds of gaining independence in a composite of major ADLs (odds ratio [OR] = 3.13 and OR = 2.87, respectively, p < 0.001). Age 60 years (OR = 0.44, p = 0.01), and complete SCI (OR = 0.43, p = 0.002) were associated with reduced odds of gaining independence in ADLs. After cervical SCI, finger flexion (C8) and elbow extension (C7) recovery translate into greater independence in eating, bladder management, and transfers. These results can be used to design individualized reinnervation plans to reanimate upper limb function and maximize independence in patients with low cervical SCI.

Core outcomes in nerve surgery: development of a core outcome set for ulnar neuropathy at the elbow.

OBJECTIVE: Ulnar neuropathy at the elbow (UNE) is common, affecting 1%-6% of the population. Despite this, there remains a lack of consensus regarding optimal treatment. This is primarily due to the difficulty one encounters when trying to assess the literature. Outcomes are inconsistently reported, which makes comparing studies or developing meta-analyses difficult or even impossible. Thus, there is a need for a core outcome set (COS) for UNE (COS-UNE) to help address this problem. The objective of this study was to utilize a modified Delphi method to develop COS-UNE. METHODS: A 5-stage approach was utilized to develop COS-UNE: stage 1, consortium development; 2, literature review to identify potential outcome measures; 3, Delphi survey to develop consensus on outcomes for inclusion; 4, Delphi survey to develop definitions; and 5, consensus meeting to finalize the COS and definitions. The study followed the Core Outcome Set-STAndards for Development (COS-STAD) recommendations. RESULTS: The Core Outcomes in Nerve Surgery (COINS) Consortium comprised 21 participants, all neurological surgeons representing 11 countries. The final COS-UNE consisted of 22 data points/outcomes covering the domains of demographic characteristics, diagnostics, patient-reported outcomes, motor/sensory outcomes, and complications. Appropriate instruments, methods of testing, and definitions were set. The consensus minimum duration of follow-up was 6 months, with the consensus optimal timepoints for assessment identified as preoperatively and 3, 6, and 12 months postoperatively. CONCLUSIONS: The authors identified consensus data points/outcomes and also provided definitions and specific scales to be utilized to help ensure that clinicians are consistent in their reporting across studies on UNE. This COS should serve as a minimum set of data to be collected in all future neurosurgical studies on UNE. The authors hope that clinicians evaluating ulnar neuropathy will incorporate this COS into routine practice and that future studies will consider this COS in the design phase.

Porcine Acellular Nerve-Derived Hydrogel Improves Outcomes of Direct Muscle Neurotization in Rats.

Background: The ability to reinnervate a muscle in the absence of a viable nerve stump is a challenging clinical scenario. Direct muscle neurotization (DMN) is an approach to overcome this obstacle; however, success depends on the formation of new muscle endplates, a process, which is often limited due to lack of appropriate axonal pathfinding cues. Objective: This study explored the use of a porcine nerve extracellular matrix hydrogel as a neuroinductive interface between nerve and muscle in a rat DMN model. The goal of the study was to establish whether such hydrogel can be used to improve neuromuscular function in this model. Materials and Methods: A common peroneal nerve-to-gastrocnemius model of DMN was developed. Animals were survived for 2 or 8 weeks following DMN with or without the addition of the hydrogel at the site of neurotization. Longitudinal postural thrust, terminal electrophysiology, and muscle weight assessments were performed to qualify and quantify neuromuscular function. Histological assessments were made to qualify the host response at the DMN site, and to quantify neuromuscular junctions (NMJs) and muscle fiber diameter. Results: The hydrogel-treated group showed a 132% increase in postural thrust at 8 weeks compared with that of the DMN alone group. This was accompanied by an 80% increase in the number of NMJs at 2 weeks, and 26% increase in mean muscle fiber diameter at 8 weeks. Conclusions: These results suggest that a nerve-derived hydrogel may improve the neuromuscular outcome following DNM.

Highly selective motor nerve block and movement analysis for preoperative evaluation of complex spastic gait.

BACKGROUND: Lower-extremity spasticity and impaired gait control after central nervous system injury are challenging to improve, because spasticity limits residual motor control while providing mechanical support. Highly selective partial neurectomies (HSPNs) can substantially reduce spasticity but may have greater risks in patients with complex lower-extremity spastic gait. OBJECTIVE: To examine the potential of ultrasound- and stimulation-guided highly selective motor nerve blocks (HSMNBs) to assess the potential impact of reduced spasticity on gait. METHODS: In this retrospective series, six patients underwent HSMNBs with movement assessment before and after the block. Range of motion, strength, position angles, surface electromyography, lower limb kinematics, and patient satisfaction were assessed. RESULTS: Pre- and post-HSMNB movement analysis yielded dichotomous gait kinematics, which facilitated surgical decisions. Of the 59 metrics evaluated, 82% demonstrated a positive improvement post-block (62% improved more than one standard deviation (SD) of typically developing means, 49% improved > 2 SD) and 16% demonstrated a negative change (2% worsened > 1 SD). CONCLUSION: HSMNB provided clear efficacy in changing clinical, surface electromyography, and gait parameters. Movement analysis provided clear and robust objective and patient-centered evidence for surgical guidance. This protocol may provide utility in evaluation of patients being considered for HSPNs for complex spastic gait patterns.

Association of upper-limb neurological recovery with functional outcomes in high cervical spinal cord injury.

OBJECTIVE: High cervical spinal cord injury (SCI) results in complete loss of upper-limb function, resulting in debilitating tetraplegia and permanent disability. Spontaneous motor recovery occurs to varying degrees in some patients, particularly in the 1st year postinjury. However, the impact of this upper-limb motor recovery on long-term functional outcomes remains unknown. The objective of this study was to characterize the impact of upper-limb motor recovery on the degree of long-term functional outcomes in order to inform priorities for research interventions that restore upper-limb function in patients with high cervical SCI. METHODS: A prospective cohort of high cervical SCI (C1-4) patients with American Spinal Injury Association Impairment Scale (AIS) grade A-D injury and enrolled in the Spinal Cord Injury Model Systems Database was included. Baseline neurological examinations and functional independence measures (FIMs) in feeding, bladder management, and transfers (bed/wheelchair/chair) were evaluated. Independence was defined as score ≥ 4 in each of the FIM domains at 1-year follow-up. At 1-year follow-up, functional independence was compared among patients who gained recovery (motor grade ≥ 3) in elbow flexors (C5), wrist extensors (C6), elbow extensors (C7), and finger flexors (C8). Multivariable logistic regression evaluated the impact of motor recovery on functional independence in feeding, bladder management, and transfers. RESULTS: Between 1992 and 2016, 405 high cervical SCI patients were included. At baseline, 97% of patients had impaired upper-limb function with total dependence in eating, bladder management, and transfers. At 1 year of follow-up, the largest proportion of patients who gained independence in eating, bladder management, and transfers had recovery in finger flexion (C8) and wrist extension (C6). Elbow flexion (C5) recovery had the lowest translation to functional independence. Patients who achieved elbow extension (C7) were able to transfer independently. On multivariable analysis, patients who gained elbow extension (C7) and finger flexion (C8) were 11 times more likely to gain functional independence (OR 11, 95% CI 2.8-47, p < 0.001) and patients who gained wrist extension (C6) were 7 times more likely to gain functional independence (OR 7.1, 95% CI 1.2-56, p = 0.04). Older age (≥ 60 years) and motor complete SCI (AIS grade A-B) reduced the likelihood of gaining independence. CONCLUSIONS: After high cervical SCI, patients who gained elbow extension (C7) and finger flexion (C8) had significantly greater independence in feeding, bladder management, and transfers than those with recovery in elbow flexion (C5) and wrist extension (C6). Recovery of elbow extension (C7) also increased the capability for independent transfers. This information can be used to set patient expectations and prioritize interventions that restore these upper-limb functions in patients with high cervical SCI.

Next-generation RNA sequencing elucidates transcriptomic signatures of pathophysiologic nerve regeneration.

The cellular and molecular underpinnings of Wallerian degeneration have been robustly explored in laboratory models of successful nerve regeneration. In contrast, there is limited interrogation of failed regeneration, which is the challenge facing clinical practice. Specifically, we lack insight on the pathophysiologic mechanisms that lead to the formation of neuromas-in-continuity (NIC). To address this knowledge gap, we have developed and validated a novel basic science model of rapid-stretch nerve injury, which provides a biofidelic injury with NIC development and incomplete neurologic recovery. In this study, we applied next-generation RNA sequencing to elucidate the temporal transcriptional landscape of pathophysiologic nerve regeneration. To corroborate genetic analysis, nerves were subject to immunofluorescent staining for transcripts representative of the prominent biological pathways identified. Pathophysiologic nerve regeneration produces substantially altered genetic profiles both temporally and in the mature neuroma microenvironment, in contrast to the coordinated genetic signatures of Wallerian degeneration and successful regeneration. To our knowledge, this study presents as the first transcriptional study of NIC pathophysiology and has identified cellular death, fibrosis, neurodegeneration, metabolism, and unresolved inflammatory signatures that diverge from pathways elaborated by traditional models of successful nerve regeneration.