Spinner, Robert J.

OBJECTIVELipomatosis of nerve (LN) is a massive enlargement of a nerve due to abundant proliferation of adipose and fibrotic tissue within the epineurium—part of the spectrum of adipose lesions of nerves, including intra- and extraneural lipomas. LN has been frequently associated with soft-tissue and/or osseous overgrowth. Unfortunately, much confusion exists since many names have been used for LN (e.g., fibrolipomatous hamartoma, macrodystrophia lipomatosa, and so on). To better understand this condition and to evaluate its association with nerve-territory overgrowth, the authors attempted to compile the world’s literature on published LN cases.METHODSPubMed and Google Scholar databases were searched to identify published articles on LN cases, using a variety of terms. Publications in all languages were assessed. All publications with cases determined likely to be LN were read. Cases that provided clear clinicopathological and/or radiological evidence of LN were labeled as “definite” and cases that demonstrated features of LN (e.g., nerve-territory overgrowth) but lacked definite proof of nerve involvement were labeled as “probable.”RESULTSInitial screening revealed a total of 2465 papers. After exclusions, 281 publications reported cases with a definite diagnosis of LN and 120 articles reported cases with a probable diagnosis of LN. The authors identified 618 definite and 407 probable cases of LN. Sex distribution was balanced (51% female). Early diagnosis was common, with two-thirds of patients having symptoms in the 1st decade of life. The most commonly affected nerve was the median nerve (n = 391). Nerve-territory overgrowth was common (62% definite LN; 78% combined cases); overgrowth was exclusive to the territory of the affected nerve in all cases but 5.CONCLUSIONSThe authors present a comprehensive review and analysis of the literature of LN cases. One of the main findings was the nerve-territory overgrowth was associated with LN, especially when present earlier in life. The authors believe that all cases of LN associated with overgrowth can be explained on anatomical grounds, even in the few reported cases in which this is not immediately obvious.

Background: The objective of the study was to evaluate and compare the clinical outcomes of in situ decompression with subcutaneous and submuscular transpositions for surgical management of advanced (McGowan stage III) cubital tunnel syndrome (CuTS). Methods: A retrospective review of patients in our institution undergoing primary surgery for CuTS from February 1989 to May 2009 was performed. Patients with advanced CuTS with a minimum of 12 months of follow-up without any previous bony or soft tissue procedures around the elbow were included. Seventy-four patients underwent 80 primary ulnar nerve surgeries. Patients’ demographics, presenting symptoms, physical examination, electrodiagnostic findings, and perioperative complications were recorded. Primary surgical techniques were compared and the risk factors for revision surgery were assessed. Results: Of the 80 surgical procedures, there were 17 decompressions (21%), 47 subcutaneous transpositions (59%), and 16 submuscular transpositions (20%). Fifty-two percent of patients had resolution of their symptoms after primary surgery. The overall complication rate after primary surgery was 12.5%. Nineteen patients (24%) had revision surgery at a median of 30 months after their primary procedure. Eight patients (42%) had symptomatic improvement after revision surgery. Patients with their dominant extremity affected, static 2-point discrimination (S2PD) greater than 10 mm, and age less than 50 years at presentation had a higher rate of revision surgery. Three patients had a second revision surgery and neurolysis for persistent symptoms. Conclusions: The overall revision rate in advanced CuTS was 24%. Forty-two percent of patients had reported subjective symptomatic improvement after revision surgery. Younger age at presentation and a greater S2PD were associated with a higher rate of revision surgery.

Abstract BACKGROUND Intraneural dissection is a useful technique for achieving gross total resection and preserving functional fascicles for peripheral nerve tumors. Finding the correct tissue plane is the critical step for safe successful enucleation. The authors hypothesized that the yellow color of benign nerve tumors can be used to identify surgical planes. OBJECTIVE To describe a technique to find the correct intraneural dissection plane based on a quantified yellow appearance during resection of benign peripheral nerve sheath tumors. METHODS Intraoperative photographs were reviewed to determine the percentage of yellow that tumors appeared at different phases of surgery. A technique was developed to quantitatively measure the amount of yellow using Photoshop. Previously published journal articles containing color images of peripheral nerve tumor resections were also analyzed for yellow tumor color. RESULTS There were 24 patients with suitable images to permit measurement of color for 3 steps of the procedure. The average percentages of yellow for tumor exposure, tumor resection, and removed specimen were 36.5%, 59.1%, and 80.4%, respectively ( P < .001). Three publications were found that contained high-quality images of at least 2 phases of the surgery with average yellow content of 47.4% and 84% ( P < .01). CONCLUSION The simple observation that a benign nerve sheath tumor is yellow in color can be used to guide surgical resection and achieve excellent outcomes. Intraneural dissection through the pseudocapsule should be pursued layer by layer until a yellow true capsule is found. By sparing functional nervous tissue within the pseudocapsule, this technique may lead to improved neurological outcomes.

Intracranial extension of temporomandibular joint (TMJ) ganglion cysts is very rare. Two previously reported cases presented clinically due to effects on cranial nerves and had obvious association with the TMJ on imaging. To the authors’ knowledge, intracranial extension of a TMJ ganglion cyst presenting with seizures and mimicking a primary brain tumor has not been previously reported. The patient underwent resection of a presumptive primary cystic temporal lobe tumor, but the lesion had histopathological features of a nonneoplastic cyst with a myxoid content. He was followed with serial imaging for 5 years before regrowth of the lesion caused new episodes of seizures requiring a repeat operation, during which the transdural defect was repaired after the adjacent segment of the TMJ was curetted. A thorough review of all imaging studies and the histopathological findings from the repeat operation led to the correct diagnosis of a TMJ ganglion cyst. This case highlights an unusual presentation of this rare lesion, as well as its potential for recurrence. TMJ ganglion cysts should be included in the differential diagnosis of cystic tumors involving the anterior temporal lobe, presenting with or without seizures. Focused imaging evaluation of the TMJ can be helpful to rule out the possible role of associated TMJ lesions.

The authors present the cases of 3 patients with severe injuries affecting the peroneal nerve combined with loss of tibialis posterior function (inversion) despite preservation of other tibial nerve function. Loss of tibialis posterior function is problematic, since transfer of the tibialis posterior tendon is arguably the best reconstructive option for foot drop, when available. Analysis of preoperative imaging studies correlated with operative findings and showed that the injuries, while predominantly to the common peroneal nerve, also affected the lateral portion of the tibial nerve/division near the sciatic nerve bifurcation. Sunderland’s fascicular topographic maps demonstrate the localization of the fascicular bundle subserving the tibialis posterior to the area that corresponds to the injury. This has clinical significance in predicting injury patterns and potentially for treatment of these injuries. The lateral fibers of the tibial division/nerve may be vulnerable with long stretch injuries. Due to the importance of tibialis posterior function, it may be important to perform internal neurolysis of the tibial division/nerve in order to facilitate nerve action potential testing of these fascicles, ultimately performing split nerve graft repair when nerve action potentials are absent in this important portion of the tibial nerve.

Restoration of shoulder lateral rotation remains a significant challenge following brachial plexus injury. Transfer of the accessory nerve to suprascapular nerve (SSN) has been widely performed, although with generally poor outcomes for lateral rotation. A recent report suggested a selective infraspinatus reinnervation technique using a radial nerve branch for SSN transfer. This cadaveric study was performed in 7 specimens (14 shoulders). We present technical modifications to achieve additional length to the recipient nerve (suprascapular) that would facilitate direct repair. Key elements of the technique are (1) isolation of the SSN immediately distal to its motor branch to supraspinatus near the superior transverse scapular ligament; and (2) delivery of the transected SSN through the spinoglenoid notch and deep to the infraspinatus for emergence in the infraspinatus‐teres minor interval. Nerve overlap of at least 21 mm was observed in all 14 dissected shoulders between the harvested SSN and radial nerve branches. The mean nerve overlap between harvested branches was 26 mm (range 21–32 mm). The mean harvested SSN length was 59 mm (range 46–80 mm). The mean length of the harvested radial nerve branch was 72 mm (range 65–85 mm). No measurements were significantly different between left and right shoulders or between males and females (smallest P value = 0.1249). Nerve diameter of the two harvested branches was judged to be appropriately compatible for surgical coaptation in all 14 dissected shoulders. We present a variation on a described technique to increase recipient suprascapular nerve length. Additional length of the recipient nerve is achieved through utilization of a more proximal dissection of the suprascapular nerve near the level of the superior transverse scapular ligament and delivering the nerve through the teres minor‐infraspinatus interval. These surgical modifications are of clinical interest when selective reinnervation of the infraspinatus muscle is considered. We believe such a targeted approach can potentially increase shoulder lateral rotation function. Clin. Anat. 32:131–136, 2019. © 2018 Wiley Periodicals, Inc.

Background: There is controversy regarding the effectiveness of brachial plexus reconstruction for elbow function in older patients, as reported outcomes are generally poor. The purpose of this study was to evaluate elbow function outcomes in patients older than 50. Methods: Fifty-eight patients older than 50 years underwent nerve grafting, transfers, or free functioning muscle transfer to improve elbow function after traumatic brachial plexus injury. Patients were evaluated preoperatively and postoperatively for elbow flexion strength and range of motion; Disabilities of the Arm, Shoulder and Hand scores; pain; concomitant trauma; severity of trauma; and type of reconstruction. Results: The average age of the patients was 57.8 years, and the average follow-up was 24.0 months. The average modified British Medical Research Council elbow flexion grade improved significantly from 0.26 to 2.63. Thirty-three patients (60 percent) achieved functional flexion greater than or equal to M3 postoperatively, compared to zero patients preoperatively. There was no correlation between age and modified British Medical Research Council grade. Active elbow range of motion improved significantly postoperatively, with no effect of age on flexion motion. More patients achieved greater than or equal to M3 flexion with nerve transfers (69 percent) compared to free functioning muscle transfer (43 percent). Patients had worse outcomes with high-energy injuries. The mean Disabilities of the Arm, Shoulder and Hand score decreased from 51.5 to 49.6 postoperatively, and the average pain score decreased from 5.0 to 4.3. Conclusion: Brachial plexus reconstruction for elbow function in patients older than 50 can yield useful flexion. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.

Perineuriomas are rare nerve sheath tumors, divided into intraneural and extraneural (soft tissue) types. Intraneural perineuriomas frequently contain TRAF7 mutations, and rarely, chr22q12 deletions. While chr22q losses can occur in soft tissue perineuriomas, comprehensive high-resolution molecular profiling has not been reported in these tumors and TRAF7 status is unknown. We used whole-exome sequencing and OncoScan single nucleotide polymorphism (SNP) array to evaluate 14 soft tissue perineuriomas. Thirteen cases showed 2 or more chromosomal abnormalities, composed primarily of large deletions. Recurrent chr22q deletions, containing the NF2 locus (n=6) and the previously unreported finding of chr17q deletions, with the NF1 locus (n=4) were frequent events and were mutually exclusive in all but1 case. In addition, 5 cases had varying chr2 deletions; and 4 cases had chr6 deletions. A chr10 deletion (previously reported in the sclerosing variant of soft tissue perineurioma) was observed in one case and another case had chr7 chromothripsis as the sole chromosomal abnormality. No TRAF7 mutations or alterations were identified in any case and no other evaluated gene (MAF<0.0001) had recurrent, deleterious mutations in >2 cases. The molecular genetic profiles showed no association with patient sex, age, tumoral histology or anatomic site. OncoScan SNP array analysis was performed on 10 cases and showed high concordance with the whole exome data, validating the large-scale deletions, duplications, and chr7 chromothripsis findings. In soft tissue perineuriomas, recurrent 22q12 deletions (with NF2) and 17q11 deletions (with NF1) appear to be mutually exclusive events, and alterations in NF1 or NF2 likely contribute to perineurioma pathogenesis, similar to other nerve sheath tumors. Moreover, the lack of TRAF7 mutations in soft tissue perineuriomas indicates divergent pathogenetic mechanisms from those of intraneural perineuriomas.

Ulnar neuropathy at the cubital tunnel is common. However, a rare form of ulnar neuropathy here is due to compression from an accessory muscle, the anconeus epitrochlearis. Reports in the literature regarding the details of this muscle's innervation are vague, so the aim of the present study was to characterize this anatomy more clearly. This was a combined review of magnetic resonance imaging (MRI) from patients with an anconeus epitrochlearis and ulnar neuropathy and cadaveric dissections to characterize the innervation of this variant muscle. A review of 11 patients and three reports of ulnar neuropathy and an anconeus epitrochlearis in the literature revealed no MRI changes consistent with acute denervation of this muscle. However, in two cases, there were signs of chronic denervation of the muscle. Dissection of five cadavers revealed that the nerve supply to the anconeus epitrochlearis originated proximal to the medial epicondyle, traveled parallel to the ulnar nerve, terminated on the deep aspect of this muscle, and had a mean length of 60 mm. This clinicoanatomical study provides evidence that the innervation of the anconeus epitrochlearis is proximal to the muscle and on its deep aspect. Clin. Anat. 32:218–223, 2019. © 2018 Wiley Periodicals, Inc.