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.

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.

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.

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.

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.

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.

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.

Masseter-to-facial nerve transfer for facial nerve reanimation.

Smooth symmetric facial muscle function is important for social interactions. When lesions of the facial nerve occur, achieving complete restoration of balanced and spontaneous facial function can be challenging. In this video, the authors demonstrate the surgical details and long-term follow-up of a masseter-to-facial nerve transfer in a 3-year-old girl who had insidious onset of a left facial palsy due to a facial nerve schwannoma. After resection, she underwent distal nerve repair with a masseter-to-zygomatic branch transfer. She demonstrated decreased lagophthalmos and good activation and excursion on the left side with near symmetry to the right side, but lacked left frontalis function. The video can be found here: https://stream.cadmore.media/r10.3171/2022.9.FOCVID22107.

Neurectomies for treatment of stroke-related upper extremity spasticity.

Limb spasticity due to central nervous system lesions can lead to substantial functional impairment. This is particularly challenging when the patient retains control of limb movements. This intraoperative video demonstrates selective neurectomies to improve spasticity. The case of a patient with left spastic hemiplegia after stroke who requested peripheral neurectomies for durable treatment of left elbow flexion spasticity is shown. The patient had substantial improvement in resting tone and achieving a relaxed, near-full extension at rest. He retains elbow flexion, which has improved in subsequent clinical follow-up evaluation. Highly selective partial denervation surgery can successfully reduce spasticity. The video can be found here: https://stream.cadmore.media/r10.3171/2022.9.FOCVID22106.

Identification of an Operative Time Threshold for Substantially Increased Postoperative Complications Among Elderly Spine Surgery Patients.

STUDY DESIGN: Retrospective cohort study. OBJECTIVES: To identify whether thresholds exist beyond which operative duration or age increases risks for complications among patients ≥65 years undergoing elective spine surgery. METHODS: Elective inpatient spine procedures unrelated to infection/trauma/tumor diagnoses in patients <65 years recorded in the 2006-2019 American College of Surgeons National Surgical Quality Improvement database were identified. Univariate analyses was used to compare 30 day complication rates among 5 operative duration and age-stratified groups. To quantify the risk of prolonged operative duration on complications, multivariate analyses were performed controlling for confounders. A generalized linear model was used to assess the individual and combined effect strength of age and operative duration on complication rates. RESULTS: Among 87,705 patients stratified by operative duration, 30 day complication rates rose nonlinearly as operative duration increased, with a sharp rise after 4.0-4.9 hours (28.3% at 4.0-4.9 hours, 51.7% at ≥5 hours, P < .001). Multivariate analysis found operative duration was independently associated with increased risk of overall complications (odds ratio 1.10→1.69, P < .001) and medical complications (odds ratio 1.19→1.98, P < .001). Although complication rates rose by age (all P < .001), age was not independently predictive of overall complications within any operative duration group on multivariate analysis. Operative duration had a greater effect (η2P = .067) than age (η2P = .003) on overall complication rates. CONCLUSIONS: Increased operative duration was strongly associated with 30 day complication rates, particularly beyond a threshold of 5 hours. Furthermore, operative duration had a notably larger effect on overall complication rates than age.

Full-endoscopic spine surgery diminishes surgical site infections - a propensity score-matched analysis.

BACKGROUND CONTEXT: Surgical site infections (SSI) are one the most frequent and costly complications following spinal surgery. The SSI rates of different surgical approaches need to be analyzed to successfully minimize SSI occurrence. PURPOSE: The purpose of this study was to define the rate of SSIs in patients undergoing full-endoscopic spine surgery (FESS) and then to compare this rate against a propensity score-matched cohort from the National Surgical Quality Improvement Program (NSQIP) database. DESIGN: This is a retrospective multicenter cohort study using a propensity score-matched analysis of prospectively maintained databases. PATIENT SAMPLE: A total of 1277 noninstrumented FESS cases between 2015 and 2021 were selected for analysis. In the nonendoscopic NSQIP cohort we selected data of 55,882 patients. OUTCOME MEASURES: The occurrence of any SSI was the primary outcome. We also collected any other perioperative complications, demographic data, comorbidities, operative details, history of smoking, and chronic steroid intake. METHODS: All FESS cases from a multi-institutional group that underwent surgery from 2015 to 2021 were identified for analysis. A cohort of cases for comparison was identified from the NSQIP database using Current Procedural Terminology of nonendoscopic cervical, thoracic, and lumbar procedures from 2015 to 2019. Trauma cases as well as arthrodesis procedures, surgeries to treat pathologies affecting more than 4 levels or spine tumors that required surgical treatment were excluded. In addition, nonelective cases, and patients with wounds worse than class 1 were also not included. Patient demographics, comorbidities, and operative details were analyzed for propensity matching. RESULTS: In the nonpropensity-matched dataset, the endoscopic cohort had a significantly higher incidence of medical comorbidities. The SSI rates for nonendoscopic and endoscopic patients were 1.2% and 0.001%, respectively, in the nonpropensity match cohort (p-value <.011). Propensity score matching yielded 5936 nonendoscopic patients with excellent matching (standard mean difference of 0.007). The SSI rate in the matched population was 1.1%, compared to 0.001% in endoscopic patients with an odds ratio 0.063 (95% confidence interval (CI) 0.009-0.461, p=.006) favoring FESS. CONCLUSIONS: FESS compares favorably for risk reduction in SSI following spinal decompression surgeries with similar operative characteristics. As a consequence, FESS may be considered the optimal strategy for minimizing SSI morbidity.

Endoscopic Techniques for Spinal Oncology: A Systematic Literature Review.

BACKGROUND: Due to its ultraminimally invasive nature, endoscopic spinal surgery is an attractive tool in spinal oncologic care. To date, there has been no comprehensive review of this topic. The authors therefore present a thorough search of the medical literature on endoscopic techniques for spinal oncology. METHODS: A systematic review using PubMed was conducted using the following keywords: endoscopic spine surgery, spinal oncology, and spinal tumors. RESULTS: Collectively, 19 cases described endoscopic spine surgery for spinal oncologic care. Endoscopic spine surgery has been employed for the care of patients with spinal tumors under the following 4 circumstances: (1) to obtain a reliable tissue diagnosis; (2) to serve as an adjunct during traditional open surgery; (3) to achieve targeted debulking; or (4) to perform definitive resection. These cases employing endoscopic techniques highlight the versatility of this approach and its utility when applied to the right patient and with an experienced surgeon. CONCLUSIONS: Our systematic review suggests that, given the right patient and an experienced surgeon, endoscopic spine surgery should be considered in the armamentarium for spinal oncologic care for both staging and definitive resection. CLINICAL RELEVANCE: This systematic literature review showed that endoscopic techniques have been successfully applied across the spectrum of care in spinal oncology, from diagnosis to definitive treatment.

Retrograde labeling correlates with motor unit number estimation in rapid-stretch nerve injury.

INTRODUCTION/AIMS: Rapid-stretch nerve injuries represent a substantial treatment challenge. No study has examined motor neuron connection after rapid-stretch injury. Our objective in this study was to characterize the electrophysiological properties of graded rapid-stretch nerve injury and assess motor neuron health using retrograde labeling and muscle adenosine triphosphatase (ATPase) histology. METHODS: Male C57BL/6 mice (n = 6 per group) were rapid-stretch injured at four levels of severity: sham injury, stretch within elastic modulus, inelastic deformation, and stretch rupture. Serial compound muscle action potential (CMAP) and motor unit number estimation (MUNE) measurements were made for 48 days, followed by retrograde labeling and muscle ATPase histology. RESULTS: Elastic injuries showed no durable abnormalities. Inelastic injury demonstrated profound initial reduction in CMAP and MUNE (P < .036) on day 2, with partial recovery by day 14 after injury (CMAP: 40% baseline, P = .003; MUNE: 55% baseline, P = .033). However, at the experimental endpoint, CMAP had recovered to baseline with only limited improvement in MUNE. Inelastic injury led to reduced retrograde-labeled neurons and grouped fiber type histology. Rupture injury had severe and nonrecovering electrophysiological impairment, dramatically reducing labeled neurons (P = .005), and atrophic or type 1 muscle fibers. There was an excellent correlation between MUNE and retrograde-labeled tibial motor neurons across injury severities (R2  = 0.96). DISCUSSION: There was no significant electrophysiological derangement in low-severity injuries but there was recoverable conduction block in inelastic injury with slow recovery, potentially due to collateral sprouting. Rupture injuries yielded permanent failure of injured axons to reinnervate. These results provide insight into the pathophysiology of clinical injuries and recovery.

Upper Limb Nerve Transfer Surgery in Patients With Tetraplegia.

Importance: Cervical spinal cord injury (SCI) causes devastating loss of upper extremity function and independence. Nerve transfers are a promising approach to reanimate upper limbs; however, there remains a paucity of high-quality evidence supporting a clinical benefit for patients with tetraplegia. Objective: To evaluate the clinical utility of nerve transfers for reanimation of upper limb function in tetraplegia. Design, Setting, and Participants: In this prospective case series, adults with cervical SCI and upper extremity paralysis whose recovery plateaued were enrolled between September 1, 2015, and January 31, 2019. Data analysis was performed from August 2021 to February 2022. Interventions: Nerve transfers to reanimate upper extremity motor function with target reinnervation of elbow extension and hand grasp, pinch, and/or release. Main Outcomes and Measures: The primary outcome was motor strength measured by Medical Research Council (MRC) grades 0 to 5. Secondary outcomes included Sollerman Hand Function Test (SHFT); Michigan Hand Outcome Questionnaire (MHQ); Disabilities of Arm, Shoulder, and Hand (DASH); and 36-Item Short Form Health Survey (SF-36) physical component summary (PCS) and mental component summary (MCS) scores. Outcomes were assessed up to 48 months postoperatively. Results: Twenty-two patients with tetraplegia (median age, 36 years [range, 18-76 years]; 21 male [95%]) underwent 60 nerve transfers on 35 upper limbs at a median time of 21 months (range, 6-142 months) after SCI. At final follow-up, upper limb motor strength improved significantly: median MRC grades were 3 (IQR, 2.5-4; P = .01) for triceps, with 70% of upper limbs gaining an MRC grade of 3 or higher for elbow extension; 4 (IQR, 2-4; P < .001) for finger extensors, with 79% of hands gaining an MRC grade of 3 or higher for finger extension; and 2 (IQR, 1-3; P < .001) for finger flexors, with 52% of hands gaining an MRC grade of 3 or higher for finger flexion. The secondary outcomes of SHFT, MHQ, DASH, and SF36-PCS scores improved beyond the established minimal clinically important difference. Both early (<12 months) and delayed (≥12 months) nerve transfers after SCI achieved comparable motor outcomes. Continual improvement in motor strength was observed in the finger flexors and extensors across the entire duration of follow-up. Conclusions and Relevance: In this prospective case series, nerve transfer surgery was associated with improvement of upper limb motor strength and functional independence in patients with tetraplegia. Nerve transfer is a promising intervention feasible in both subacute and chronic SCI.

Development of an acellular nerve cap xenograft for neuroma prevention.

Neuroma formation following limb amputation is a prevalent and debilitating condition that can deeply affect quality of life and productivity. Several approaches exist to prevent or treat neuromas; however, no approach is either consistently reliable or surgically facile, with high rates of neuroma occurrence and/or recurrence. The present study describes the development and testing of a xenogeneic nerve cap graft made from decellularized porcine nerve. The grafts were tested in vitro for cellular removal, cytotoxicity, mechanical properties, and morphological characteristics. The grafts were then tested in rat sciatic nerve gap reconstruction and nerve amputation models for 8 weeks. Gross morphology, electrophysiology, and histopathology assessments were performed to determine the ability of the grafts to limit pathologic nerve regrowth. In vitro testing showed well decellularized and demyelinated nerve cap graft structures without any cytotoxicity from residual reagents. The grafts had a proximal socket for the proximal nerve stump and longitudinally oriented internal pores. Mechanical and surgical handling properties suggested suitability for implantation as a nerve graft. Following 8 weeks in vivo, the grafts were well integrated with the proximal and distal nerve segments without evidence of fibrotic adhesions to the surrounding tissues or bulbous outgrowth of the nerve. Electrophysiology revealed absence of nerve conduction within the remodeled nerve cap grafts and significant downstream muscle atrophy. Histologic evaluation showed well organized but limited axonal regrowth within the grafts without fibrous overgrowth or neuromatous hypercellularity. These results provide proof of concept for a novel xenograft-based approach to neuroma prevention.

Incorporating Blood Flow in Nerve Injury and Regeneration Assessment.

Peripheral nerve injury is a significant public health challenge, with limited treatment options and potential lifelong impact on function. More than just an intrinsic part of nerve anatomy, the vascular network of nerves impact regeneration, including perfusion for metabolic demands, appropriate signaling and growth factors, and structural scaffolding for Schwann cell and axonal migration. However, the established nerve injury classification paradigm proposed by Sydney Sunderland in 1951 is based solely on hierarchical disruption to gross anatomical nerve structures and lacks further information regarding the state of cellular, metabolic, or inflammatory processes that are critical in determining regenerative outcomes. This review covers the anatomical structure of nerve-associated vasculature, and describes the biological processes that makes these vessels critical to successful end-organ reinnervation after severe nerve injuries. We then propose a theoretical framework that incorporates measurements of blood vessel perfusion and inflammation to unify perspectives on all mechanisms of nerve injury.

Machine learning approach to differentiation of peripheral schwannomas and neurofibromas: A multi-center study.

BACKGROUND: Non-invasive differentiation between schwannomas and neurofibromas is important for appropriate management, preoperative counseling, and surgical planning, but has proven difficult using conventional imaging. The objective of this study was to develop and evaluate machine learning approaches for differentiating peripheral schwannomas from neurofibromas. METHODS: We assembled a cohort of schwannomas and neurofibromas from 3 independent institutions and extracted high-dimensional radiomic features from gadolinium-enhanced, T1-weighted MRI using the PyRadiomics package on Quantitative Imaging Feature Pipeline. Age, sex, neurogenetic syndrome, spontaneous pain, and motor deficit were recorded. We evaluated the performance of 6 radiomics-based classifier models with and without clinical features and compared model performance against human expert evaluators. RESULTS: One hundred and seven schwannomas and 59 neurofibromas were included. The primary models included both clinical and imaging data. The accuracy of the human evaluators (0.765) did not significantly exceed the no-information rate (NIR), whereas the Support Vector Machine (0.929), Logistic Regression (0.929), and Random Forest (0.905) classifiers exceeded the NIR. Using the method of DeLong, the AUCs for the Logistic Regression (AUC = 0.923) and K Nearest Neighbor (AUC = 0.923) classifiers were significantly greater than the human evaluators (AUC = 0.766; p = 0.041). CONCLUSIONS: The radiomics-based classifiers developed here proved to be more accurate and had a higher AUC on the ROC curve than expert human evaluators. This demonstrates that radiomics using routine MRI sequences and clinical features can aid in differentiation of peripheral schwannomas and neurofibromas.

Highly Selective Partial Neurectomies for Spasticity: A Single-Center Experience.

BACKGROUND: Sedating antispastic medications and focal therapies like botulinum toxin are the most common therapies for spasticity but are temporary and must be performed continuously for a principally static neurological insult. Alternatively, highly selective partial neurectomies (HSPNs) may reduce focal spasticity more permanently. OBJECTIVE: To quantify the change in spasticity after HSPN and assess patient satisfaction. METHODS: We retrospectively reviewed the records of patients with upper- and/or lower-extremity spasticity treated with HSPN from 2014 to 2018. Only cases with a modified Ashworth scale (MAS) score independently determined by a physical therapist were included. Pre- and postoperative MAS, complications, and patient satisfaction were evaluated. RESULTS: The 38 patients identified (24 male, 14 female; mean age 49 yr) underwent a total of 88 procedures for focal spasticity (73% upper extremity, 27% lower extremity). MAS scores were adjusted to a 6-point scale for evaluation. The mean preoperative and final postoperative follow-up adjusted MAS scores were 3.6 and 1.7, respectively (P < .001), which represents average MAS less than 1+. Positive, neutral, and worse results were described by 91%, 6%, and 3% of patients, respectively. Four patients requested revision surgery. No perioperative complications were encountered. CONCLUSION: This is the first North American series to analyze HSPN for spasticity and the only series based on independent evaluation results. HSPN surgery demonstrated objective short- and long-term reduction in spasticity with minimal morbidity and excellent patient satisfaction.