Nerve-Targeted Surgical Treatments for Spasticity: A Narrative Review.

Spasticity is a potentially debilitating symptom of various acquired and congenital neurologic pathologies that, without adequate treatment, may lead to long-term disability, compromise functional independence, and negatively impact mental health. Several conservative as well as non-nerve targeted surgical strategies have been developed for the treatment of spasticity, but these may be associated with significant drawbacks, such as adverse side effects to medication, device dependence on intrathecal baclofen pumps, and inadequate relief with tendon-based procedures. In these circumstances, patients may benefit from nerve-targeted surgical interventions such as (i) selective dorsal rhizotomy, (ii) hyperselective neurectomy, and (iii) nerve transfer. When selecting the appropriate surgical approach, preoperative patient characteristics, as well as the risks and benefits of nerve-targeted surgical intervention, must be carefully evaluated. Here, we review the current evidence on the efficacy of these nerve-targeted surgical approaches for treating spasticity across various congenital and acquired neurologic pathologies.

Surgical Technique: Brachioradialis to Extensor Carpi Radialis Longus and Brevis Nerve Transfers for Tetraplegia.

Improving upper extremity function in high cervical spinal cord injury (SCI) patients with tetraplegia is a challenging task owing to the limited expendable donor muscles and nerves that are available. Restoring active wrist extension for these patients is critical because it allows for tenodesis grasp. This is classically achieved with brachioradialis (BR) to extensor carpi radialis brevis (ECRB) tendon transfer, but outcomes are suboptimal because BR excursion is insufficient and its origin proximal to the elbow further limits the functionality of the tendon transfer, particularly in the absence of elbow extension. As an alternative approach to restore wrist extension in patients with ICSHT group 1 SCI, we present the first clinical report of the BR to extensor carpi radialis longus (ECRL) and BR to ECRB nerve transfers.

Nerve Transfer Surgery in Acute Flaccid Myelitis: Prognostic Factors, Long-Term Outcomes, Comparison With Natural History.

BACKGROUND: Nerve transfer surgery is sometimes offered to patients with acute flaccid myelitis (AFM). The objectives of this study were to evaluate surgical efficacy, assess which clinical and neurophysiological data are valuable for preoperative planning, and report long-term outcomes. METHODS: This is a single-center, retrospective case series of patients with AFM who received nerve transfer surgery. All patients had preoperative electromyography and nerve conduction studies (EMG/NCS). Matched control muscles that did not receive nerve transfer surgery were defined in the same cohort. RESULTS: Ten patients meeting inclusion criteria received a total of 23 nerve transfers (19 upper extremity, four lower extremity). The mean age at symptom onset was 3.8 years, surgery was 0.5 to 1.25 years after diagnosis, and mean follow-up was 2.3 years (range 1.3 to 4.5 years). Among muscles with preoperative strength Medical Research Council (MRC) grade 0, muscles receiving nerve transfers performed significantly better than those that did not (MRC grade 2.17 ± 0.42 vs 0 ± 0, respectively, P = 0.0001). Preoperative EMG/NCS predicted worse outcomes in recipient muscles with more abundant acute denervation potentials (P = 0.0098). Donor nerves found to be partially denervated performed equally well as unaffected nerves. Limited data suggested functional improvement accompanying strength recovery. CONCLUSIONS: Nerve transfer surgery is an effective strategy to restore strength for patients with AFM with persistent, severe motor deficits. Postoperative outcomes in patients with complete paralysis are better than the natural history of disease. This study demonstrates the utility of preoperative clinical and electrophysiological data in guiding patient selection for nerve transfer surgery.

Treatment decisions and the use of MEK inhibitors for children with neurofibromatosis type 1-related plexiform neurofibromas.

Neurofibromatosis type 1 (NF1), the most common tumor predisposition syndrome, occurs when NF1 gene variants result in loss of neurofibromin, a negative regulator of RAS activity. Plexiform neurofibromas (PN) are peripheral nerve sheath tumors that develop in patients with NF1 and are associated with substantial morbidity and for which, until recently, the only treatment was surgical resection. However, surgery carries several risks and a proportion of PN are considered inoperable. Understanding the genetic underpinnings of PN led to the investigation of targeted therapies as medical treatment options, and the MEK1/2 inhibitor selumetinib has shown promising efficacy in pediatric patients with NF1 and symptomatic, inoperable PN. In a phase I/II trial, most children (approximately 70%) achieved reduction in tumor volume accompanied by improvements in patient-reported outcomes (decreased tumor-related pain and improvements in quality of life, strength, and range of motion). Selumetinib is currently the only licensed medical therapy indicated for use in pediatric patients with symptomatic, inoperable NF1-PN, with approval based on the results of this pivotal clinical study. Several other MEK inhibitors (binimetinib, mirdametinib, trametinib) and the tyrosine kinase inhibitor cabozantinib are also being investigated as medical therapies for NF1-PN. Careful consideration of multiple aspects of both disease and treatments is vital to reduce morbidity and improve outcomes in patients with this complex and heterogeneous disease, and clinicians should be fully aware of the risks and benefits of available treatments. There is no single treatment pathway for patients with NF1-PN; surgery, watchful waiting, and/or medical treatment are options. Treatment should be individualized based on recommendations from a multidisciplinary team, considering the size and location of PN, effects on adjacent tissues, and patient and family preferences. This review outlines the treatment strategies currently available for patients with NF1-PN and the evidence supporting the use of MEK inhibitors, and discusses key considerations in clinical decision-making.

Consensus-Based Best Practice Guidelines for the Management of Spinal Deformity and Associated Tumors in Pediatric Neurofibromatosis Type 1: Screening and Surveillance, Surgical Intervention, and Medical Therapy.

BACKGROUND: Spinal conditions, such as scoliosis and spinal tumors, are prevalent in neurofibromatosis type 1 (NF1). Despite the recognized importance of their early detection and treatment, there remain knowledge gaps in how to approach these manifestations. The purpose of this study was to utilize the experience of a multidisciplinary committee of experts to establish consensus-based best practice guidelines (BPGs) for spinal screening and surveillance, surgical intervention, and medical therapy in pediatric patients with NF1. METHODS: Using the results of a prior systematic review, 10 key questions that required further assessment were first identified. A committee of 20 experts across medical specialties was then chosen based on their clinical experience with spinal deformity and tumors in NF1. These were 9 orthopaedic surgeons, 4 neuro-oncologists/oncologists, 3 neurosurgeons, 2 neurologists, 1 pulmonologist, and 1 clinical geneticist. An initial online survey on current practices and opinions was conducted, followed by 2 additional surveys via a formal consensus-based modified Delphi method. The final survey involved voting on agreement or disagreement with 35 recommendations. Items reaching consensus (≥70% agreement or disagreement) were included in the final BPGs. RESULTS: Consensus was reached for 30 total recommendations on the management of spinal deformity and tumors in NF1. These were 11 recommendations on screening and surveillance, 16 on surgical intervention, and 3 on medical therapy. Five recommendations did not achieve consensus and were excluded from the BPGs. CONCLUSION: We present a set of consensus-based BPGs comprised of 30 recommendations for spinal screening and surveillance, surgical intervention, and medical therapy in pediatric NF1.

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.

Treatment of C5 Palsy: An International Survey of Peripheral Nerve Surgeons.

STUDY DESIGN: International survey. OBJECTIVES: C5 palsy (C5P) is a neurological complication affecting 5-10% of patients after cervical decompression surgery. Most cases improve with conservative treatment; however, nearly 20% of patients may be left with residual deficits. Guidelines are lacking on C5P management and timing of surgical intervention. Therefore, we sought to survey peripheral nerve surgeons on their management of C5P. METHODS: An online survey was distributed centered around a patient with C5P after posterior cervical decompression and fusion. Questions included surgeon demographics, diagnostic modalities, and timing and choice of operation. Responses were summarized and the chi-squared and Kruskal-Wallis H tests were used to examine differences across specialties. RESULTS: A total of 154 surgeons responded to the survey, of which 59 (38%) indicated that they manage C5P cases. Average time prior to operating was 4.5 ± 2.2 months for complete injuries and 6.6 ± 3.2 months for partial injuries, with neurosurgeons significantly more likely to wait longer periods for complete (P = .01) and partial injuries (P = .03). Foraminotomies were selected by 19% of surgeons, while 92% selected nerve transfers. Transfer of the ulnar nerve to the musculocutaneous nerve was the most common choice (81%), followed by transfer of the radial nerve to the axillary nerve (58%). CONCLUSION: Consensus exists among peripheral nerve surgeons on the use of nerve transfers for surgical treatment in cases with severe motor weakness failing to improve. Most surgeons advocate for early intervention in complete injuries. Disagreement concerns the type of nerve transfer employed, timing of surgery, and efficacy of foraminotomy.

Is dorsal root entry zone lesioning effective and safe for managing continuous versus paroxysmal pains post-brachial plexus avulsion?

OBJECTIVE: Patients with brachial plexus avulsion (BPA) experience chronic deafferentation pain characterized by two patterns: continuous background pain and electrical shooting paroxysmal attacks. The authors' aim was to report the effectiveness and safety of dorsal root entry zone (DREZ) lesioning in relieving the two forms of pain over short and long periods. METHODS: All patients who underwent DREZ lesioning performed by the senior author for medically refractory BPA-related pain between July 1, 2016, and June 30, 2020, in Johns Hopkins Hospital were followed up. The intensity levels for continuous and paroxysmal pains were evaluated using the numeric rating scale (NRS) preoperatively and at 4 time points postsurgery, including the day of discharge, with a mean hospital stay of 5.6 ± 1.8 days; first postoperative clinic visit (33.0 ± 15.7 days); short-term follow-up (4.0 ± 1.4 months); and long-term follow-up (3.1 ± 1.3 years). The percent of pain relief according to the NRS was categorized into excellent (≥ 75%), fair (25%-74%), and poor (< 25%). RESULTS: A total of 19 patients were included, with 4 (21.1%) lost to long-term follow-up. The mean age was 52.7 ± 13.6 years; 16 (84.2%) were men, and 10 (52.6%) had left-sided injuries. A motor vehicle accident was the most common etiology of BPA (n = 16, 84.2%). Preoperatively, all patients had motor deficits, and 8 (42.1%) experienced somatosensory deficits. The greatest pain relief was observed at the first postoperative and short-term follow-up visits, with the lowest proportions of patients having continuous pain (26.3% and 23.5%, respectively) and paroxysmal pain (5.3% and 5.9%, respectively). Also, the highest reductions in mean NRS scores were observed for first postoperative and short-term follow-up visits (continuous 1.1 ± 2.1 and 1.1 ± 2.3; paroxysms 0.4 ± 1.4 and 0.5 ± 1.7, respectively) compared to the preoperative symptomatology (continuous 6.7 ± 3.0; paroxysms 7.9 ± 4.3) (p < 0.001). Most patients had excellent relief of continuous pain (82.4% and 81.3%) and of paroxysms (90.9% and 90.0%) at the first postoperative visit and short-term follow-up visit, respectively. The pain relief benefits had diminished by 3 years after surgery but remained significantly better than in the preoperative assessment. At the last evaluation, the proportion of patients achieving excellent relief of paroxysmal pain (66.7%) was double that for continuous pain (35.7%) (p < 0.001). New sensory phenomena were observed among 10 patients (52.6%), and 1 patient developed a motor deficit. CONCLUSIONS: DREZ lesioning is an effective and safe option for relieving BPA-associated pain, with good long-term outcomes and better benefits for paroxysmal pain than for the continuous pain component.

Differences in the surgical treatment of adult and pediatric brachial plexus injuries among peripheral nerve surgeons.

OBJECTIVES: Peripheral nerve surgeons disagree on the optimal timing and treatment of brachial plexus injuries (BPI). This study aims to survey peripheral nerve surgeons on their management of BPI, including disagreement. METHODS: Surgeons responded to a case-based survey involving traumatic and birth injuries leading to BPI involving the upper and lower trunks, and pre- and post-ganglionic injuries. RESULTS: Out of 255 invited surgeons, 154 participated, with specialties of Neurosurgery (33.7%), Plastic surgery (32.5%), and Orthopedics (32.5%). For the adult C5-6 avulsion injury, 97.4% agreed they would operate. There was 46.2% disagreement regarding the pediatric upper trunk neuroma-in-continuity case, and similar disagreement (50.0%) was recorded on exploring the brachial plexus for a pediatric lower trunk injury case. High percentages of surgeons were more likely to explore the plexus, such as at upper BPI. Also, most participants reported nerve transfer for the upper and lower trunk avulsion injuries, but there was 55.6% disagreement regarding nerve transfer for the infant with the upper trunk neuroma-in-continuity. Among those elected to perform nerve transfer, most (70.0%-84.5%) would perform an accessory-to-suprascapular nerve transfer for upper BPI, while brachialis-to-anterior interosseous and supinator branch of the radial nerve-to-posterior interosseous were preferred for lower BPI (30.0%-55.9%). CONCLUSIONS: Substantial disagreement exists among peripheral nerve surgeons in managing adult and pediatric BPI. In adult BPI, most prefer to operate at the time of the presentation and perform extensive nerve transfers. The accessory-suprascapular transfer was recommended for upper BPI, while brachialis and radial nerves were preferred for lower BPI. The most significant disagreements exist in operation and nerve transfer for pediatric upper BPI and brachial plexus explorations. Geography, specialty, and operative volume contribute to the differences seen.

Novel Approach of Femur Shortening With Insertion of Expandable Rod to Achieve End-to-End Repair of Sciatic Nerve Laceration.

BACKGROUND: Sciatic nerve injuries are challenging for diagnosis and treatment. Particularly in proximally located high-grade injuries, neurorrhaphy often has poor outcomes. Most advocate autologous grafting and some more recently have suggested the value of knee flexion braces to facilitate end-to-end repair. OBJECTIVE: To describe a case of femur shortening to facilitate tension-free, end-to-end sciatic nerve neurorrhaphy. METHODS: The patient was a 17-year-old man who was injured by the propeller of a motor boat and suffered a series of lacerations to both lower extremities including transection of his right sciatic nerve in the proximal thigh. After extensive mobilization of the nerve, a greater than 7-cm gap was still present. The patient was treated with femur shortening to facilitate end-to-end coaptation. He subsequently had an expandable rod placed which was lengthened 1 mm per day until his leg length was symmetric. RESULTS: Within 7 months postoperatively, the patient had an advancing Tinel sign and paresthesias to the dorsum of his foot. Nine months postoperatively, he had early mobility in his plantarflexion. CONCLUSION: We present a novel method of femur shortening with insertion of an expandable rod to facilitate direct end-to-end and tension-free sciatic nerve neurorrhaphy in a proximally located injury. Furthermore, larger scale and comparative studies are warranted to further explore this and other techniques.

Development and validation of a prediction model for outcomes after transaxillary first rib resection for neurogenic thoracic outlet syndrome following strict Society for Vascular Surgery diagnostic criteria.

OBJECTIVE: Neurogenic thoracic outlet syndrome (NTOS) is the most common form of thoracic outlet syndrome. However, NTOS has remained difficult to diagnose and treat successfully. The purpose of the present study was to generate a predictive clinical calculator for postoperative outcomes after first rib resection (FRR) for NTOS. METHODS: We performed a retrospective review of patients who had undergone FRR for NTOS at a single tertiary care institution between 2016 and 2020. A multivariate stepwise logistic regression analysis was performed to assess the association of the percentage of improvement after FRR with the patient baseline characteristics, pertinent clinical characteristics, and diagnostic criteria set by the Society for Vascular Surgery. The primary outcome was subjective patient improvement after FRR. A prediction risk calculator was developed using backward stepwise multivariate logistic regression coefficients. Bootstrapping was used for internal validation. RESULTS: A total of 208 patients (22.2% male; mean age, 35.8 ± 12.8 years; median follow-up, 44.9 months) had undergone 243 FRRs. Of the 208 patients, 94.7% had had symptoms localized to the supraclavicular area, and 97.6% had had symptoms in the hand. All the patients had had positive symptoms reproduced by the elevated arm stress test and upper limb tension test. Another reasonably likely diagnosis was absent for all the patients. Of the 196 patients who had received a lidocaine injection, 180 (93.3%) had experienced improvement of NTOS symptoms. Of the 95 patients who had received a Botox injection, 82 (74.6%) had experienced improvement of NTOS symptoms. Receiver operating characteristic curve analysis was used to assess the model. The area under the curve for the backward stepwise multivariate logistic regression model was 0.8. The multivariate logistic regression analyses revealed that the significant predictors of worsened clinical outcomes included hand weakness (adjusted odds ratio [aOR], 4.28; 95% confidence interval [CI], 1.04-17.74), increasing age (aOR, 0.93; 95% CI, 0.88-0.99), workers' compensation or litigation case (aOR, 0.09; 95% CI, 0.01-0.82), and symptoms in the dominant hand (aOR, 0.20; 95% CI, 0.05-0.88). CONCLUSIONS: Using retrospective data from a single-institution database, we have developed a prediction calculator with moderate to high predictive ability, as demonstrated by an area under the curve of 0.8. The tool (available at: https://jhhntosriskcalculator.shinyapps.io/NTOS_calc/) is an important adjunct to clinical decision-making that can offer patients and providers realistic and personalized expectations of the postoperative outcome after FRR for NTOS. The findings from the present study have reinforced the diagnostic criteria set by the Society for Vascular Surgery. The calculator could aid physicians in surgical planning, referrals, and counseling patients on whether to proceed with surgery.

Natural History of Brachial Plexus, Peripheral Nerve, and Spinal Schwannomas.

BACKGROUND: Management of sporadic schwannomas is often dictated by a patient's clinical presentation and the tumor's behavior. For patients who are managed nonsurgically, there are little data available about the expected natural history. OBJECTIVE: To evaluate the natural history and growth patterns of extracranial schwannomas including tumors of the distal peripheral nerves, spine, and brachial plexus. METHODS: A retrospective review was performed to identify patients with nonsyndromic extracranial schwannomas at a single tertiary care institution diagnosed between 2002 and 2019. Patient data and tumor characteristics including volume were recorded. RESULTS: Two hundred twenty-seven patients were identified (mean age 51 years, 42% male, average of 27.8-month follow-up). Tumor location was distal peripheral nerve in 82, brachial plexus in 36, and paraspinal in 109. At the time of diagnosis, peripheral lesions were significantly larger than spinal (59 m 3 vs 13 cm 3 ) and brachial plexus lesions (15 cm 3 ). Distinct growth patterns were seen with both distal peripheral nerve and spinal lesions; 34/82 peripheral nerve lesions had fast growth (ß = 0.176%/day), and 48 had slow growth (ß = 0.021%/day; P < .01). Spinal schwannomas similarly had 30 fast-growing (ß = 0.229%/day), 16 moderate-growing (ß = 0.071%/day), and 63 slow-growing (ß = 0.022%/day; P = .03) subtypes. The brachial plexus had relatively homogeneous growth patterns (ß = 0.065%/day). Females had 2.9 times greater odds of having the fast-growing subtype. CONCLUSION: Distinct growth patterns were seen in extracranial sporadic schwannomas based on tumor location and patient demographics. Fast (>80% volume change per year) vs slow (5%-10% per year) tumor growth can often be ascertained within 2 follow-up images. Awareness of these patterns might have implications for patient counseling and therapeutic decision-making.

Dorsal Root Entry Zone Lesioning for the Treatment of Pain After Brachial Plexus Avulsion Injury: 2-Dimensional Operative Video and Technical Report.

BACKGROUND: Neuropathic pain after nerve root or plexus avulsion injury is disabling and often refractory to medical therapy. Dorsal root entry zone (DREZ) lesioning is a neurosurgical procedure that disrupts the pathological generation and transmission of nociceptive signaling through the selective lesioning of culprit neurons within the dorsal horn of the spinal cord. OBJECTIVE: To present a case report and describe the operative technique for cervical spinal cord DREZ lesioning using radiofrequency thermocoagulation. METHODS: We present the case of a 29-year-old man who experienced a traumatic right-sided brachial plexus avulsion injury. The patient experienced severe neuropathic pain in his distal right upper extremity. He underwent cervical spinal DREZ lesioning. Postoperatively, he reported immediate and total pain relief that was sustained on follow-up at 3 months. We describe the operative technique for DREZ lesioning, including preoperative considerations, patient position, incision, approach, exposure, microsurgical dissection, DREZ lesioning, fixation, and closure. RESULTS: The goal of DREZ lesioning is the selective destruction of nociceptive fibers within the lateral bundle of the dorsal rootlet and superficial layers of the dorsal horn gray matter, while preserving the medial inhibitory fibers. DREZ lesioning targets the putative pain generator and ascending pain pathways that mediate the characteristic neuropathic pain after avulsion injury. Neurological complications include worsening pain or motor and sensory deficits of the ipsilateral lower extremity. CONCLUSION: DREZ lesioning provides an effective and durable treatment for neuropathic pain after nerve root or plexus avulsion injury.

Management of neurofibromatosis type 1-associated plexiform neurofibromas.

Plexiform Neurofibromas (PN) are a common manifestation of the genetic disorder neurofibromatosis type 1 (NF1). These benign nerve sheath tumors often cause significant morbidity, with treatment options limited historically to surgery. There have been tremendous advances over the past two decades in our understanding of PN, and the recent regulatory approvals of the MEK inhibitor selumetinib are reshaping the landscape for PN management. At present, there is no agreed upon PN definition, diagnostic evaluation, surveillance strategy, or clear indications for when to initiate treatment and selection of treatment modality. In this review, we address these questions via consensus recommendations from a panel of multidisciplinary NF1 experts.

Nerve Transfers After Cervical Spine Surgery: Multi-Institutional Case Series and Review of the Literature.

BACKGROUND: Up to 10% of cervical spine surgeries are complicated by postoperative weakness. Although many patients recover with nonoperative management, some require surgery for restoration of function. OBJECTIVE: To present the indications and outcomes of patients undergoing nerve transfers after developing weakness secondary to cervical spine decompression. METHODS: A retrospective review of patients from 2 academic medical centers who underwent nerve transfer for C5-6 root injury after cervical spine surgery was performed. RESULTS: Of the 10 treated patients, 9 experienced recovery at last follow-up, demonstrating improvements in strength and motion in the affected muscles. Successful nerve transfers occurred between 3 and 8 months after the index spinal surgery and included spinal accessory nerve to suprascapular nerve, triceps branch to anterior division of the axillary nerve, and/or ulnar or median fascicles to motor branches of the musculocutaneous nerve. The unsuccessful patient underwent nerve transfer surgery approximately 11 months after the index operation and failed to obtain functional recovery. CONCLUSIONS: Patients who experience C5-6 weakness after cervical spine surgery should be evaluated and considered for nerve transfer surgery if they have continued severe functional deficits at 6 months postoperatively. Earlier referral for nerve transfer is associated with improved functional outcomes in this cohort.

Sciatic-to-Femoral Nerve End-to-End Coaptation for Proximal Lower Extremity Function in Patients With Acute Flaccid Myelitis: Technical Note and Review of the Literature.

BACKGROUND: Acute flaccid myelitis (AFM) is an acute-onset anterior horn disease resulting in flaccid paralysis of extremities, trunk, facial, and cervical musculature in children following upper respiratory or gastrointestinal viral illness. Nerve transfer procedures have been shown to restore function. OBJECTIVE: To present a technical description of sciatic-to-femoral nerve transfers in 4 children with AFM. METHODS: Retrospective review of relevant cases was performed. RESULTS: A total of 4 cases are presented of young children with persistent quadriparesis in the setting of AFM, presenting between 4 and 15 mo following initial diagnosis. Electromyography showed denervation of muscles innervated by the femoral nerve, with sparing of the sciatic distribution. The obturator nerve was also denervated in all patients. We therefore elected to pursue sciatic-to-femoral transfers to restore active knee extension. These transfers involved end-to-end coaptation of a sciatic nerve fascicle to the femoral nerve motor branches supplying quadriceps muscles. CONCLUSION: We present technical descriptions of bilateral sciatic-to-femoral nerve neurotization for the restoration of quadriceps function in 4 patients with AFM. The sciatic nerve fascicles are a reasonable alternative donor nerve for patients with proximal muscle paralysis and limited donor options in the lower extremity.

Use of electromyography to predict likelihood of recovery following C5 palsy after posterior cervical spine surgery.

BACKGROUND: C5 palsy affects approximately 5% to 10% of patients undergoing cervical spine surgery. It has a significant negative impact on patient quality-of-life outcomes and healthcare costs. Although >80% of patients improve, some are left with persistent, debilitating deficits. Our objective was to examine if electrodiagnostic testing could be used to successfully identify patients likely to experience complete, partial, and no recovery. METHODS: Patients undergoing posterior cervical decompression and fusion at a single institution over a 10-year period were identified. Those experiencing postoperative C5 palsy were included. Outcomes examined included motor recovery of the affected deltoid as a function of time, and changes in electrodiagnostic testing as a function of time since injury. Electrodiagnostic testing included electromyography and was sub-analyzed by time of acquisition postinjury. Deltoid strength was graded on manual motor testing using the 5-point medical research council grading system. RESULTS: Of 77 patients experiencing C5 palsy, 29 had postoperative electrodiagnostic testing. Patients experiencing complete recovery on average achieved functional (4/5) strength by 6-weeks post injury and 4+ per 5 strength by 6-months. Those experiencing partial recovery only achieved antigravity strength (3/5) by 6-weeks and low-function (4-/5) strength by 6-months. Electrodiagnostic testing performed 6-weeks to 6-months postinjury demonstrated that those experiencing complete recovery were more likely to have normal motor unit (MU) recruitment than those experiencing partial (p<.001) or no recovery (p=.008). The presence of ≥2+ fibrillation on tests acquired ≤6-weeks of injury identified patients unlikely to experience any recovery with a positive predictive value (PPV) of 88.9%. The presence of normal MU recruitment on tests acquired 6-weeks to 6-months postinjury identified patients likely to experience complete recovery with a PPV of 87.5%. CONCLUSIONS: Electrodiagnostic testing may be a valuable means of differentiating between patients with C5 palsy likely to experience complete, partial, or no recovery. Testing between 6-weeks and 6-months post onset may aid in identifying those least likely to have a complete recovery. No MUs at 4 to 6-months, or reduced units with strength that is not improving, portends a poor long-term outcome. In this population, peripheral nerve transfers may be considered sooner.

Cryoanalgesia of the anterior femoral cutaneous nerve (AFCN) for the treatment of neuropathy-mediated anterior thigh pain: anatomy and technical description.

OBJECTIVE: To describe and illustrate the magnetic resonance imaging (MRI) anatomy of the anterior femoral cutaneous nerve (AFCN) and a new technique for cryoanalgesia of the AFCN for long-term analgesic treatment of recalcitrant AFCN-mediated neuropathic pain. MATERIALS AND METHODS: Using a procedural high-resolution MRI technique, we describe the MRI anatomy of the AFCN. Three patients (mean age, 48 years; range, 41-67 years) with selective nerve block-verified recalcitrant AFCN-mediated anterior thigh pain were enrolled to undergo cryoanalgesia of the AFCN. Procedures were performed under MRI guidance using clinical wide-bore MR imaging systems and commercially available cryoablation system with MR-conditional probes. Outcome variables included technical success, clinical effectiveness including symptom relief measured on an 11-point visual analog scale, frequency of complications, and procedure time. RESULTS: Procedural MRI allowed to successfully demonstrate the course of the AFCN, accurate cryoprobe placement, and monitoring of the ice ball, which resulted in technically successful iceball growth around the AFCN in all cases. All procedures were clinically effective, with median pain intensity decreasing from 8 (7-9) before the procedure to 1 (0-2) after the procedure. The cryoanalgesia effect persisted during a 12-month follow-up period in all three patients. No major complications occurred. The average total procedure time was 98 min (range, 85-125 min). CONCLUSION: We describe the MRI anatomy of the AFCN and a new technique for cryoanalgesia of the AFCN using MRI guidance, which permits identification of the AFCN, selective targeting, and iceball monitoring to achieve long-term AFCN-mediated neuropathic pain relief.

Trends in Utilization and Cost of Inpatient Spinal Cord Stimulation: Analysis of Data from 2008 to 2014.

OBJECTIVE: In this study, we sought to characterize contemporary trends in cost and utilization of spinal cord stimulation (SCS). METHODS: The Healthcare Cost and Utilization Project-National Inpatient Sample was queried for inpatient admissions from 2008 to 2014 where SCS was performed. We then determined the rates and costs of SCS performed in this time frame to treat diagnoses that we classified as device-related complications, degenerative spine disease, pain syndromes, and neuropathies/neuritis/nerve lesions. Least-squares regression was performed to determine the yearly trends for each indication adjusted by the total number of yearly hospitalizations for that diagnosis. RESULTS: We identified a total of 6876 admissions in whom an SCS was performed. The overall rate of inpatient SCS procedures performed has decreased by 45% from 2008 to 2014 (14.0 to 7.7 procedures per 100,000 admissions). Adjusted analysis for yearly trends also demonstrated a declining trend for all indications; however, this was not found to be statistically significant, except for device-related complications (P = 0.004). The median inflation-adjusted cost of an admission where SCS was performed increased slightly by 7.4% from $26,200 (IQR: $16,700-$33,800) in 2008 to $28,100 (IQR: $19,600-$36,900) in 2014. Billed hospital charges demonstrated a significant increase with median inflation-adjusted admission charge of $66,068 in 2008 to $110,672 in 2014. CONCLUSIONS: Despite a declining contemporary trend in inpatient SCS, an increase was noted in admission costs and hospital charges. A significant declining trend was noted in revision SCS implantations due to device-related complications.

A clinically and genomically annotated nerve sheath tumor biospecimen repository.

Nerve sheath tumors occur as a heterogeneous group of neoplasms in patients with neurofibromatosis type 1 (NF1). The malignant form represents the most common cause of death in people with NF1, and even when benign, these tumors can result in significant disfigurement, neurologic dysfunction, and a range of profound symptoms. Lack of human tissue across the peripheral nerve tumors common in NF1 has been a major limitation in the development of new therapies. To address this unmet need, we have created an annotated collection of patient tumor samples, patient-derived cell lines, and patient-derived xenografts, and carried out high-throughput genomic and transcriptomic characterization to serve as a resource for further biologic and preclinical therapeutic studies. In this work, we release genomic and transcriptomic datasets comprised of 55 tumor samples derived from 23 individuals, complete with clinical annotation. All data are publicly available through the NF Data Portal and at http://synapse.org/jhubiobank.