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The purpose of the study is to examine presentation, injury patterns, and clinical course, for COVID-19-related peripheral nerve injury following mechanical ventilation.A multicenter retrospective study of patients with COVID-19 complicated by acute respiratory distress syndrome (ARDS) that required mechanical ventilation was undertaken. Patient records were reviewed for intensive care unit and intubation characteristics, prone or lateral decubitus positioning, and the onset of neuropathy diagnosis.Between September 2020 and January 2022, 11 patients were diagnosed with peripheral neuropathy, including 9 with brachial plexopathy following COVID-19 infection. Each patient developed ARDS requiring mechanical ventilation for a median of 39 days. Six patients (54.5%) underwent prone positioning and 1 lateral decubitus. Neuropathies involved 5 brachial pan-plexopathies, 2 incomplete brachial plexopathies, 2 lower trunk plexopathies, 1 radial neuropathy, and 1 bilateral ulnar neuropathy. At a mean follow-up of 10.2 months, patients with brachial pan-plexopathies demonstrated signs of reinnervation proximally, and 1 resolved to a radial mononeuropathy; however, the majority have demonstrated minimal clinical improvements.Our series demonstrates that peripheral neuropathies and especially brachial plexopathies have occurred following mechanical ventilation for ARDS-related COVID-19 infections. Contrary to prior COVID-19 studies, only 54.5% of these patients underwent prone positioning. Aside from a traumatic disturbance of prone positioning, the increased incidence of neuropathy may involve an atraumatic effect of COVID-19 via direct invasion of nerves, autoantibody targeting of nervous tissue, or hypercoagulation-induced microthrombotic angiopathy.

We sought to identify predictors of failed triceps motor branch transfer to the anterior division of the axillary nerve (AN) for shoulder abduction reconstruction after a brachial plexus injury (BPI).A case-control study of adult AN or brachial plexus patients treated with a triceps motor branch transfer to the anterior division of the AN with a minimum 18 months of follow-up was performed. The failure group (case group) was defined as modified British Medical Research Council muscle scale (mBMRC) postoperative deltoid grade ≤2 and was compared to the successful outcome group (control group), defined as mBMRC postoperative deltoid grade ≥3. Clinical variables, injury mechanism, time from injury to surgery, root avulsion status, electrodiagnostic studies, rotator cuff injuries, scapula fracture, Disabilities of the Arm Shoulder and Hand scores, and preoperative triceps strength were analyzed. Subgroup analysis was performed for patients with isolated AN injuries and those with BPI.A total of 69 patients met inclusion/exclusion criteria, of whom 23 regained ≥M3 deltoid muscle strength and 52° ± 69° of shoulder abduction (successful outcome group) and 46 regained ≤M2 deltoid muscle strength and 27° ± 30° of shoulder abduction (failure group). Preoperative triceps weakness (M ≤4) was significantly more common in the failure group (63% vs. 30%, P = 0.032); preoperative triceps muscle fibrillations were significantly more common in the failure group (61% vs. 30%, P = 0.02). Isolated AN injuries presented better preoperative motion and postoperative outcomes results compared to BPI.Use of triceps motor branch associated with fibrillations or weakness resulted in statistically poorer outcomes compared to the use of a normal triceps motor branch in the restoration of anterior AN function after nerve transfer.

Peripheral nerve injuries associated with reverse total shoulder arthroplasty (rTSA) are rarely reported and are often dismissed as neuropraxias, particularly in the setting of perioperative nerve blocks. The purpose of this study was to evaluate nerve injuries following rTSA to determine if there is a pattern of injury and to evaluate outcomes of patients who sustain an intraoperative nerve injury.A retrospective review was performed identifying patients who underwent rTSA and had a concomitant major nerve injury who were referred to a multidisciplinary peripheral nerve injury clinic. Demographic data, preoperative nerve block use, physical examination, electrodiagnostic studies, injury pattern, and time from injury to referral was collected. Radiographs, Quick Disabilities of the Arm, Shoulder and Hand questionnaire (QuickDASH) score, and outcomes surveys were obtained at final follow-up.Twenty-two patients were identified with postoperative nerve injuries. Average time from injury to referral was 9.0 months, with 18.8 months' follow-up. Eight patients had undergone prior shoulder surgery, and 11 patients had prior shoulder trauma. Injury patterns were variable and involved diffuse pan-plexopathies with severity localized to the posterior and medial cords (11), the upper trunk (5), lateral cord (2), and axillary nerve (4). The average postoperative acromiohumeral distance (AHD) was 3.7 cm, with an average change of 2.9 cm. The average postoperative lateral humeral offset (LHO) was 1.1 cm, with an average change of 0.2 cm. Seventeen patients were confirmed to have undergone preoperative nerve blocks, which were initially attributed as the etiology of nerve injury. Eighteen patients were initially treated with observation: 11 experienced residual debilitating neuropathic pain and/or disability, and 7 had substantial improvement. One patient underwent nerve transfers, whereas the others underwent procedures for hand dysfunction improvement. The average QuickDASH score was 53.5 at average of 4 years post rTSA.Although uncommon, permanent peripheral nerve injuries following rTSA do occur with debilitating effects. Preoperative regional blocks were used in most cases, but none of the blocks could be directly attributed to the nerve injuries. Nerve injuries were likely secondary to traction at the time of arthroplasty and/or substantial distalization and lateralization of the implants. Patients with medial cord injuries had the most debilitating loss of hand function. Surgeons should be cognizant of these injuries and make a timely referral to a peripheral nerve specialist.

During spine surgery, surgeons are exposed to vibrations from surgical drills. Increased exposure to vibration can result in neurologic, vascular, and musculoskeletal impairments. To reduce these risks, occupational health standards have been implemented to limit exposure levels. The purpose of this study was to quantify human exposure to hand-arm vibration from a surgical drill during a simulation of a common spine procedure.Vibration measurements were collected during three 30-second surgical trials on a fresh frozen cadaver torso specimen using a standard surgical drill. The daily vibration exposure A(8) was evaluated on the basis of International Organization for Standardization 5349-1, and the occupational health standards, exposure action value, and exposure limit value were calculated.On the basis of vibration exposure, surgeons in this study reached their exposure limits in 8 minutes to monitor tool usage and 32 minutes to terminate equipment usage.The results demonstrate that a common surgical drill transmits hand-arm vibration levels approaching the exposure action value and exposure limit value over short periods of use. Further investigation is needed to determine the total vibration exposure over an entire workday, specifically in surgeons who perform multiple surgeries within a single day.

A multidisciplinary brachial plexus clinic has been a relatively new concept, offering different surgical speciality perspectives on the treatment of brachial plexus injuries. The resulting collaborative effort has proven to be greater than the sum of its parts. In this review, the history, philosophy of care, development/implementation and impact of a creation of a multidisciplinary brachial plexus team at the Mayo Clinic are detailed.

BACKGROUND Myofibromas are benign mesenchymal tumors, classically presenting in infants and young children in the head and neck region. Perineural involvement, especially in peripheral nerves within the upper extremity, is extremely rare in myofibromas. OBSERVATIONS The authors present the case of a 16-year-old male with a 4-month history of an enlarging forearm mass and rapidly progressive dense motor weakness in wrist, finger, and thumb extension. Preoperative imaging and fine needle biopsy confirmed the diagnosis of a benign isolated myofibroma. Given the dense paralysis, operative management was indicated, and intraoperative exploration showed extensive involvement of tumor within the radial nerve. The infiltrated nerve segment was excised along with the tumor, and the resulting 5-cm nerve gap was reconstructed using autologous cabled grafts. LESSONS Perineural pseudoinvasion can be an extremely rare and atypical feature of nonmalignancies, resulting in dense motor weakness. Extensive nerve involvement may still necessitate nerve resection and reconstruction, despite the benign etiology of the lesion.

BACKGROUND Perineuriomas are peripheral nerve sheath tumors that are composed of benign, localized proliferations of perineural cells and further subclassified as intraneural or extraneural (soft tissue) based on their relationship to the histological boundaries of the nerve. Multiple histological variants have been described, and herein the authors present the first known case of a pseudolipoblastic perineurioma affecting the nerve. OBSERVATIONS A 52-year-old woman presented with a 5-year history of progressive, severe left buttock pain radiating down to the top of her foot and ankle, without any associated weakness, with a large mass in her sciatic nerve noted on magnetic resonance imaging (MRI). She underwent resection, which demonstrated a pseudolipoblastic perineurioma of the sciatic nerve, an unusual histological subtype composed of perineurial cells with an abundant clear intracytoplasmic background. Postoperatively, her pain resolved, and follow-up MRI showed no tumor persistence or recurrence. LESSONS On imaging, this lesion had a benign appearance, with areas suggestive of subacute hemorrhage, and was associated with a nerve. Although the distinctive morphological features of this lesion may suggest liposarcoma, careful morphological evaluation and appropriate immunohistochemical studies allow its correct classification.

Introduction: Sacral and presacral schwannomas are rare and account for a minority of spinal schwannomas. We aim to present our institution’s experience surgically treating sacral schwannomas over twenty-one years. Additionally, we assess the literature for surgical cases of sacral schwannomas to compare tumor characteristics and outcomes following resection.Methods: Data on demographics, presenting symptoms, lesion characteristics, surgical management, and outcomes were collected for 27 patients treated surgically for sacral or presacral schwannoma between 1997 and 2018 at all Mayo Clinic locations and compared to those of patients found in the literature. Results: We identified 31 studies in the literature containing 93 patients with sacral schwannoma treated surgically. Our patients and those in the literature experienced similar symptoms, with the most common symptom being pain and the least common being sexual dysfunction, and age at diagnosis. Most of our patients (59.3%) reported full recovery from preoperative symptoms, while a minority reported a partial recovery (33.3%) and no recovery (11.1%). A smaller percentage of patients found in the literature experienced full recovery (31.9%) and partial recovery (29.8%) but also no recovery (1.1%). Our patients experienced fewer complications (14.8% versus 25.5%).Conclusion: Outcomes of patients with sacral or presacral schwannomas vary based on patient demographics, tumor characteristics, symptoms, and surgical treatment. Among the range of symptoms experienced by these patients, the most common is pain. Prognosis improves and overall survival rate is high when the surgical approach towards sacral schwannomas is prepared and executed appropriately.

OBJECTIVE Malignant peripheral nerve sheath tumors (MPNSTs) are rare tumors found throughout the body, with their clinical course in children still not completely understood. Correspondingly, this study aimed to determine survival outcomes and specific clinical predictors of survival in this population from a large national database. METHODS All patients with MPNSTs aged ≤ 18 years in the US National Cancer Database (NCDB) between 2005 and 2016 were retrospectively reviewed. Data were summarized, and overall survival was modeled using Kaplan-Meier and Cox regression analyses. RESULTS A total of 251 pediatric patients with MPNSTs (132 [53%] females and 119 [47%] males) were identified; the mean age at diagnosis was 13.1 years (range 1–18 years). There were 84 (33%) MPNSTs located in the extremities, 127 (51%) were smaller than 1 cm, and 22 (9%) had metastasis at the time of diagnosis. In terms of treatment, surgery was pursued in 187 patients (74%), chemotherapy in 116 patients (46%), and radiation therapy in 129 patients (61%). The 5-year overall survival rate was estimated at 52% (95% CI 45%–59%), with a median survival of 64 months (range 36–136 months). Multivariate regression revealed that older age (HR 1.10, p < 0.01), metastases at the time of diagnosis (HR 2.14, p = 0.01), and undergoing biopsy only (HR 2.98, p < 0.01) significantly and independently predicted a shorter overall survival. Chemotherapy and radiation therapy were not statistically significant. CONCLUSIONS In this study, the authors found that older patient age, tumor metastases at the time of diagnosis, and undergoing only biopsy significantly and independently predicted poorer outcomes. Only approximately half of patients survived to 5 years. These results have shown a clear survival benefit in pursuing maximal safe resection in pediatric patients with MPNSTs. As such, judicious workup with meticulous resection by an expert team should be considered the standard of care for these tumors in children.

Background Although partial cystic degeneration is commonly observed in schwannoma, cases of totally cystic forms have also been reported. A literature review of cases describing totally cystic schwannoma was performed to assess their imaging characteristics. Methods PubMed was queried with the phrases “totally cystic schwannoma,” “purely cystic schwannoma,” and “completely cystic schwannoma.” A total of 19 papers encompassing 22 cases of reported totally cystic schwannoma were included. Patient characteristics, clinical presentation, and reported imaging characteristics were recorded. Computed tomography and magnetic resonance images from the papers were collected and reviewed by a senior musculoskeletal radiologist. Results The most frequent presenting location of these lesions was in spinal nerve roots. The interpretations of imaging reported in the papers described a homogeneous lesion that was isointense to slightly hyperintense to cerebrospinal fluid (CSF) on T1-weighted images. On contrast administration, the studies described a thin rim of “ring-like” enhancement around the lesion. Our reinterpretation of the imaging revealed heterogeneous lesions that were hyperintense to CSF on T1-weighted images. Post-contrast images typically demonstrated an irregularly thickened enhancing rim. Most images showed evidence of solid components in the lesion, with many containing enhancing soft tissue elements. The observed imaging features were not consistent with simple cystic lesions. Conclusions Review of the imaging studies of the reported cases of completely cystic schwannoma did not produce any convincing examples of purely cystic lesions. The description of these lesions as “totally cystic” appears to be a misnomer and has diagnostic and therapeutic implications.

BACKGROUND The articular (synovial) theory describes the formation of intraneural ganglion cysts through defects in the capsule of synovial joints. While the articular theory is gaining significant traction in the literature, it is not universally accepted. Therefore, the authors present a case of a plainly visible peroneal intraneural cyst, although the subtle joint connection was not identified specifically at the time of surgery, with subsequent rapid extraneural cyst recurrence. The joint connection was not immediately evident on review of the magnetic resonance imaging, even to the authors who have a large experience with this clinical entity. The authors report this case to demonstrate that all intraneural ganglion cysts have joint connections, although they may be difficult to identify. OBSERVATIONS An occult joint connection in the intraneural ganglion poses a unique diagnostic and management dilemma. High-resolution imaging is a valuable tool used to identify the articular branch joint connection as part of the surgical planning. LESSONS Based on the articular theory, all intraneural ganglion cysts will have a joint connection through an articular branch, although this may be small or nearly invisible. Failure to appreciate this connection can lead to cyst recurrence. A high index of suspicion of the articular branch is needed for surgical planning.

BACKGROUND Neuromuscular choristoma (NMC) is a rare congenital lesion in which muscle tissue is admixed with nerve fascicles within a peripheral nerve. Patients commonly present in early childhood with neuropathy, plexopathy, or chronic undergrowth in the distribution of the affected nerve. OBSERVATIONS The authors present the case of a 35-year-old man with unrecognized neuromuscular NMC of the sciatic nerve, which resulted in recurrent, multicentric NMC-associated desmoid-type fibromatosis (NMC-DTF) within the nerve territory in association with a Marjolin ulcer, a cutaneous malignancy. LESSONS Based on anatomical and pathophysiological findings described in this case report, the authors support the association between NMC-DTF and Marjolin ulcer.

BACKGROUND Macrodystrophia lipomatosa (MDL) is characterized by progressive overgrowth affecting soft tissues and bony structures and is part of lipomatous overgrowth syndromes. MDL has been associated with lipomatosis of the nerve (LN), an adipose lesion of nerve that has a pathognomonic magnetic resonance imaging (MRI) appearance as well as a mutation in the PIK3CA gene. The authors present a case of occult LN in the setting of MDL. OBSERVATIONS A 2-year-old boy with progressive soft tissue overgrowth of his proximal right lower extremity was initially diagnosed with neurofibromatosis type 1 (NF1). At our institution, NF1 as well as other overgrowth syndromes including PTEN hamartoma tumor syndrome were excluded. He was diagnosed as having so-called MDL. Upon reinterpretation of the patient’s MRI studies, short-segment LN involving the proximal sciatic nerve and part of lumbosacral plexus was identified. He underwent 2 debulking/liposuction procedures for soft tissue overgrowth. Genetic testing of tissue revealed a mutation in PIK3CA. LESSONS Thorough clinical examination (for signs of overgrowth) as well as an MRI study of the entire neural pathway is a critical part of the diagnostic workup to evaluate for LN. The authors believe that an increasing association of LN, even when occult, will emerge that will explain many cases with marked nerve-territory overgrowth.

Although superior gluteal nerve (SGN) injury can have significant morbidity, to date, surgical strategies for its repair are scant in the literature. Specifically, neurotization options have not been explored. To address this deficiency in the literature, the current cadaveric feasibility study was performed. Via a transgluteal approach on 16 cadaveric sides, the proximal sciatic nerve and the entrance of the SGN into the gluteus medius and minimus were identified. Additionally, branches from the sciatic nerve to the hamstring muscles were traced proximally to confirm their position in relation to the sciatic nerve as a whole. These branches were cut at the level of the ischial tuberosity and teased away from the sciatic nerve proximally to the greater sciatic foramen and transferred superolateral to the SGN. The diameter of each nerve branch was measured as well as its available length for reaching the SGN. All branches of the sciatic nerve to the hamstring muscles arose from the anteromedial part of the nerve. The mean diameters of the branches to the semimembranosus, semitendinosus, and biceps femoris muscles were 2.1, 1.9, and 1.5 mm, respectively. The mean diameter of the SGN was 3.1 mm and the mean distance from this entrance point to the ischial spine was 7.2 cm. The mean length of the donor nerve was 8.5 cm. Based on our study, use of a tibial-innervated hamstring branch as a donor for nerve transfer to the SGN is feasible.

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.

OBJECTIVE Spinal procedures are increasingly conducted as outpatient procedures, with a growing proportion conducted in ambulatory surgery centers (ASCs). To date, studies reporting outcomes and cost analyses for outpatient spinal procedures in the US have not distinguished the various outpatient settings from each other. In this study, the authors used a state-level administrative database to compare rates of overnight stays and nonroutine discharges as well as index admission charges and cumulative 7-, 30-, and 90-day charges for patients undergoing outpatient lumbar decompression in freestanding ASCs and hospital outpatient (HO) settings. METHODS For this project, the authors used the Florida State Ambulatory Surgery Database (SASD), offered by the Healthcare Cost and Utilization Project (HCUP), for the years 2013 and 2014. Patients undergoing outpatient lumbar decompression for degenerative diseases were identified using CPT (Current Procedural Terminology) and ICD-9 codes. Outcomes of interest included rates of overnight stays, rate of nonroutine discharges, index admission charges, and subsequent admission cumulative charges at 7, 30, and 90 days. Multivariable analysis was performed to assess the impact of outpatient type on index admission charges. Marginal effect analysis was employed to study the difference in predicted dollar margins between ASCs and HOs for each insurance type. RESULTS A total of 25,486 patients were identified; of these, 7067 patients (27.7%) underwent lumbar decompression in a freestanding ASC and 18,419 (72.3%) in an HO. No patient in the ASC group required an overnight stay compared to 9.2% (n = 1691) in the HO group (p < 0.001). No clinically significant difference in the rate of nonroutine discharge was observed between the two groups. The mean index admission charge for the ASC group was found to be significantly higher than that for the HO group ($35,017.28 ± $14,335.60 vs $33,881.50 ± $15,023.70; p < 0.001). Patients in ASCs were also found to have higher mean 7-day (p < 0.001), 30-day (p < 0.001), and 90-day (p = 0.001) readmission charges. ASC procedures were associated with increased charges compared to HO procedures for patients on Medicare or Medicaid (mean index admission charge increase $4049.27, 95% CI $2577.87–$5520.67, p < 0.001) and for patients on private insurance ($4775.72, 95% CI $4171.06–$5380.38, p < 0.001). For patients on self-pay or no charge, a lumbar decompression procedure at an ASC was associated with a decrease in index admission charge of −$10,995.38 (95% CI −$12124.76 to −$9866.01, p < 0.001) compared to a lumbar decompression procedure at an HO. CONCLUSIONS These “real-world” results from an all-payer statewide database indicate that for outpatient spine surgery, ASCs may be associated with higher index admission and subsequent 7-, 30-, and 90-day charges. Given that ASCs are touted to have lower overall costs for patients and better profit margins for physicians, these analyses warrant further investigation into whether this cost benefit is applicable to outpatient spine procedures.

OBJECTIVE Sustained postoperative opioid use after elective surgery is a matter of growing concern. Herein, the authors investigated incidence and predictors of long-term opioid use among patients undergoing elective lumbar spine surgery, especially as a function of opioid prescribing practices at postoperative discharge (dose in morphine milligram equivalents [MMEs] and type of opioid). METHODS The OptumLabs Data Warehouse (OLDW) was queried for postdischarge opioid prescriptions for patients undergoing elective lumbar decompression and discectomy (LDD) or posterior lumbar fusion (PLF) for degenerative spine disease. Only patients who received an opioid prescription at postoperative discharge and those who had a minimum of 180 days of insurance coverage prior to surgery and 180 days after surgery were included. Opioid-naive patients were defined as those who had no opioid fills in 180 days prior to surgery. The following patterns of long-term postoperative use were investigated: additional fills (at least one opioid fill 90–180 days after surgery), persistent fills (any span of opioid use starting in the 180 days after surgery and lasting at least 90 days), and Consortium to Study Opioid Risks and Trends (CONSORT) criteria for persistent use (episodes of opioid prescribing lasting longer than 90 days and 120 or more total days’ supply or 10 or more prescriptions in 180 days after the index fill). Multivariable logistic regression was performed to identify predictors of long-term use. RESULTS A total of 25,587 patients were included, of whom 52.7% underwent PLF (n = 13,486) and 32.5% (n = 8312) were opioid-naive prior to surgery. The rates of additional fills, persistent fills, and CONSORT use were 47%, 30%, and 23%, respectively, after PLF and 35.4%, 19%, and 14.2%, respectively, after LDD. The rates among opioid-naive patients were 18.9%, 5.6%, and 2.5% respectively, after PLF and 13.3%, 2.0%, and 0.8%, respectively, after LDD. Using multivariable logistic regression, the following were identified to be significantly associated with higher risk of long-term opioid use following PLF: discharge opioid prescription ≥ 500 MMEs, prescription of a long-acting opioid, female sex, multilevel surgery, and comorbidities such as depression and drug abuse (all p < 0.05). Elderly (age ≥ 65 years) and opioid-naive patients were found to be at lower risk (all p < 0.05). Similar results were obtained on analysis for LDD with the following significant additional risk factors identified: discharge opioid prescription ≥ 400 MMEs, prescription of tramadol alone at discharge, and inpatient surgery (all p < 0.05). CONCLUSIONS In an analysis of pharmacy claims from a national insurance database, the authors identified incidence and predictors of long-term opioid use after elective lumbar spine surgery.

OBJECTIVE To determine the accuracy of preoperative ultrasound and MRI in surgically confirmed spinal accessory nerve injuries and present the benefits of a multimodality image review. MATERIALS AND METHODS A retrospective review of 38 consecutive patients referred to a peripheral nerve surgical practice at an academic teaching hospital with surgically confirmed spinal accessory nerve injuries. All cases were reviewed for patient demographics, date and cause of injury, preoperative EMG, and surgical diagnosis and management. Additionally, prospective interpretation of preoperative ultrasound and MRI reports were reviewed for concordance or discordance with the surgical diagnosis. RESULTS Iatrogenic injury was present in 37 (97%) cases and most commonly a result of an excisional lymph node biopsy (68%). Surgically confirmed spinal accessory nerve injury diagnoses consisted of 25 (66%) stump neuromas and 13 (34%) incomplete nerve injuries. Nine months was the average time from injury to surgery. Twenty-nine patients underwent preoperative ultrasound and/or MRI evaluation: 12 ultrasound only, 10 MRI only, and seven with both ultrasound and MRI. Eighteen (95%) preoperative ultrasound reports compared to four (24%) preoperative MRI reports were concordant with the surgical diagnosis. In the seven cases with both preoperative ultrasound and MRI, six had discordant ultrasound and MRI imaging diagnoses for which the ultrasound was concordant with the surgical diagnoses in all cases. CONCLUSION Preoperative ultrasound more accurately characterizes spinal accessory nerve injuries compared to MRI and should serve as the modality of choice when a spinal accessory nerve injury is suspected.

Objective Neurosurgical patients are at a higher risk of having a severe course of coronavirus disease 2019 (COVID-19). The objective of this study was to determine morbidity, hospital course, and mortality of neurosurgical patients during the coronavirus disease 2019 (COVID-19) pandemic in a multicenter health care system. Methods A retrospective observational study was conducted to identify all hospitalized neurosurgical patients positive for COVID-19 from March 11, 2020 to November 2, 2020 at Mayo Clinic and the Mayo Clinic Health System. Results Eleven hospitalized neurosurgical patients (0.68%) were positive for COVID-19. Four patients (36.6%) were men and 7 (63.3%) were women. The mean age was 65.7 years (range, 35–81 years). All patients had comorbidities. The mean length of stay was 13.4 days (range, 4–30 days). Seven patients had a central nervous system malignancy (4 metastases, 1 meningioma, 1 glioblastoma, and 1 schwannoma). Three patients presented with cerebrovascular complications, comprising 2 spontaneous intraparenchymal hemorrhages and 1 ischemic large-vessel stroke. One patient presented with an unstable traumatic spinal burst fracture. Four patients underwent neurosurgical/neuroendovascular interventions. Discharge disposition was to home in 5 patients, rehabilitation facility in 3, and hospice in 3. Five patients had died at follow-up, 3 within 30 days from COVID-19 complications and 2 from progression of their metastatic cancer. Conclusions COVID-19 is rare among the inpatient neurosurgical population. In all cases, patients had multiple comorbidities. All symptomatic patients from the respiratory standpoint had complications during their hospitalization. Deaths of 3 patients who died within 30 days of hospitalization were all related to COVID-19 complications. Neurosurgical procedures were performed only if deemed emergent.

OBJECTIVEThe aim of this study was to examine the role of intraoperative neuromonitoring (IONM) during resection of benign peripheral nerve sheath tumors in achieving gross-total resection (GTR) and in reducing postoperative neurological complications.METHODSData from consecutive adult patients who underwent resection of a benign peripheral nerve sheath tumor at 7 participating institutions were combined. Propensity score matching was used to balance covariates. The primary outcomes of interest were the association between IONM and GTR and the association of IONM and the development of a permanent postoperative neurological complication. The secondary outcomes of interest were the association between IONM and GTR and the association between IONM and the development of a permanent postoperative neurological complication in the subgroup of patients with tumors involving a motor or mixed nerve. Univariate and multivariate logistic regression were then performed on the propensity score–matched samples to assess the ability of the independent variables to predict the outcomes of interest.RESULTSA total of 337 patients who underwent resection of benign nerve sheath tumors were included. In multivariate analysis, the use of IONM (OR 0.460, 95% CI 0.199–0.978; p = 0.047) was a significant negative predictor of GTR, whereas none of the variables, including IONM, were associated with the occurrence of a permanent postoperative neurological complication. Within the subgroup of motor/mixed nerve tumors, in the multivariate analysis, IONM (OR 0.263, 95% CI 0.096–0.723; p = 0.010) was a significant negative predictor of a GTR, whereas IONM (OR 3.800, 95% CI 1.925–7.502; p < 0.001) was a significant positive predictor of a permanent postoperative motor deficit.CONCLUSIONSOverall, 12% of the cohort had a permanent neurological complication, with new or worsened paresthesias most common, followed by pain and then weakness. The authors found that formal IONM was associated with a reduced likelihood of GTR and had no association with neurological complications. The authors believe that these data argue against IONM being considered standard of care but do not believe that these data should be used to universally argue against IONM during resection of benign nerve sheath tumors.

BACKGROUND Delayed facial palsy (DFP) after vestibular schwannoma resection is a well-documented, yet poorly understood condition. The exact pathophysiological mechanisms of DFP are unknown, although diminished intraoperative nerve response has been shown to be a prognostic factor. To date, no such condition has been described in regard to peripheral nerve schwannomas. OBSERVATIONS Here the authors present the first reported cases of delayed motor weakness (DMW) after peripheral schwannoma resection of the ulnar nerve at the elbow and peroneal nerve in the popliteal fossa. Both patients presented with a mass lesion and radiating paresthesias and had normal motor function preoperatively. Immediately after surgical resection, the patients had full strength. Within 24 hours, both patients exhibited marked weakness that gradually resolved over the course of several weeks. LESSONS DMW after peripheral schwannoma resection is a rare condition likely akin to delayed facial nerve palsy after VS resection. The mechanism of this phenomenon remains unknown, although symptoms appear to self-resolve with time. A better understanding of the processes driving this condition may allow for therapies that can expedite and improve long-term outcomes.

BACKGROUND Schwannomas of the peripheral nerves are benign tumors that can very rarely undergo malignant transformation. These lesions are particularly challenging to diagnose via noninvasive techniques but can have significant implications for treatment. OBSERVATIONS This is a case of a 70-year-old female with a prior history of a right sciatic notch tumor that was diagnosed as a conventional schwannoma via histology from an initial biopsy and subsequent surgical debulking. Unfortunately, she experienced significant worsening of her motor deficit, whereby her postoperative foot weakness progressed to complete foot drop in less than 2 years. In addition, she demonstrated significant radiological progression, with more than 1 to 2 cm of growth in each dimension at her subsequent evaluation, along with intractable right leg pain. An additional operation was performed to completely remove the 7 × 8 cm tumor, and histology demonstrated angiosarcoma within a schwannoma. There was no evidence of recurrence at 15 months, and the patient had significant improvement in her pain. LESSONS Rapidly worsening function and radiological progression are not typically seen with conventional benign nerve sheath tumors and should prompt consideration of other lesions. Angiosarcoma within schwannoma is a rare pathology and optimal therapies for these tumors in terms of surgical timing and adjuvant therapy are still unknown.

A variety of approaches have been described to obtain rudimentary grasp after traumatic pan-brachial plexus injury in adults. The aim of this study is to evaluate hand prehension after a gracilis single-stage free functioning muscle transfer.Twenty-seven patients who underwent gracilis single-stage free functioning muscle transfer for elbow flexion and hand prehension after a pan-plexus injury were included. All patients presented with a minimum of 2 years of follow-up. Postoperative finger flexion, elbow flexion strength, preoperative and postoperative Disability of the Arm, Shoulder, and Hand questionnaire scores, secondary hand procedures, complications, and demographic characteristics were analyzed.Twenty patients (74%) demonstrated active finger pull-through. Only six patients (25%) considered their hand function useful for daily activities. Disability of the Arm, Shoulder, and Hand score improved by 13.1 ± 13.7 ( P0.005). All patients were expected to require one secondary procedure (wrist fusion, thumb carpometacarpal fusion, and/or thumb interphalangeal fusion) because no extensor reconstruction was performed. These were performed in 89%, 78%, and 74% of patients, respectively. Four postoperative complications (hematoma, seroma, wound dehiscence, and skin paddle loss) occurred. No flap loss occurred.In pan-plexus injuries, the use of a gracilis single-stage free functioning muscle transfer is an alternative to the double free functioning muscle transfer procedure and contralateral C7 transfer, especially for patients who are unable to undergo two to three important operations in a short period of time. Further research and studies are required to improve hand function in these patients.Therapeutic, IV.

BACKGROUND Foot drop is a common complaint with a broad differential diagnosis making imaging a key part of the diagnostic workup. The authors present a patient with an occult peroneal intraneural ganglion cyst who underwent imaging with high-frequency ultrasound (US) and high-resolution magnetic resonance imaging (MRI) to highlight the role of such techniques in cases of peroneal neuropathy. OBSERVATIONS Intraneural ganglion cysts are emerging as a common cause of common peroneal neuropathy. Imaging with US and MRI is a valuable tool used to illustrate the pertinent anatomy and identify the articular branch joint connection and cyst as part of the surgical planning and definitive management. LESSONS Intraneural ganglion cysts can be small or nearly invisible and failure to appreciate the intraneural cyst can lead to symptom or cyst persistence or recurrence. High-resolution modalities can be useful in the diagnosis and surgical planning of difficult cases.

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