Spinner, Robert J.

Lipomatosis of nerve (LN) is a rare disorder of peripheral nerves that produces proliferation of interfascicular adipose tissue. It may be associated with soft-tissue and bony overgrowth within the affected nerve territory. LN has been almost exclusively reported in appendicular peripheral nerves; the median nerve at the wrist and palm is among the most common locations. The authors present a new pattern of LN that shows circumferential proliferation of fat around the epineurium of the nerve. They believe that this case and the two other documented examples in the literature (also affecting cervical and thoracic spinal nerves) share the same new pattern of LN. Defining the full spectrum of adipose lesions of the nerve and establishing a cause-effect relationship with nerve-territory overgrowth disorders may offer options for future management through targeted nerve lesioning.

OBJECTIVE The etiology of intraneural ganglion cysts has been controversial. In recent years, substantial evidence has been presented to support the articular (synovial) theory for their pathogenesis. The authors sought to 1) perform a systematic review of the world's literature on intraneural cysts, and 2) reinterpret available published MR images in articles by other authors to identify unrecognized joint connections. METHODS In Part 1, all cases were analyzed for demographic data, duration of symptoms, the presence of a history of trauma, whether electromyography or nerve conduction studies were performed, the type of imaging, surgical treatment, presence of a joint connection, intraneural cyst recurrence, and postoperative imaging. Two univariate analyses were completed: 1) to compare the proportion of intraneural ganglion cyst publications per decade and 2) to assess the number of recurrences from 1914 to 2003 compared with the years 2004–2015. Three multivariate regression models were used to identify risk factors for intraneural cyst recurrence. In Part 2, the authors analyzed all available published MR images and obtained MR images from selected cases in which joint connections were not identified by the original authors, specifically looking for unrecognized joint connections. Two univariate analyses were done: 1) to determine a possible association between the identification of a joint connection and obtaining an MRI and 2) to assess the number of joint connections reported from 1914 to 2003 compared with 2004 to 2015. RESULTS In Part 1, 417 articles (645 patients) were selected for analysis. Joint connections were identified in 313 intraneural cysts (48%). Both intraneural ganglion cyst cases and cyst recurrences were more frequently reported since 2004 (statistically significant difference for both). There was a statistically significant association between cyst recurrence and percutaneous aspiration as well as failure to disconnect the articular branch or address the joint. In Part 2, the authors identified 43 examples of joint connections that initially went unrecognized: 27 based on their retrospective MR image reinterpretation of published cases and 16 of 16 cases from their sampling of original MR images from published cases. Overall, joint connections were more commonly found in patients who received an MRI examination and were more frequently reported during the years 2004 to 2015 (statistically significant difference for both). CONCLUSIONS This comprehensive review of the world's literature and the MR images further supports the articular (synovial) theory and provides baseline data for future investigators.

Background: The adductor magnus (AM) has historically been a potential source of confusion in patients with suspected proximal hamstring avulsion injuries. Purpose: To investigate the anatomic characteristics of the AM, including its osseous origin, anatomic dimensions, and relationship to the proximal hamstring tendons. Study Design: Descriptive laboratory study. Methods: Dissection of the AM origin was performed in 11 (8 cadavers) fresh-frozen hip-to-foot cadaveric hemipelvis specimens. The gross anatomy and architecture of the proximal hamstring and AM tendons were studied. After dissecting the hamstring tendons away from their origin, the dimension, shape, and orientation of the tendon footprints on the ischial tuberosity were determined. Results: The AM was identified in all cadaveric specimens. The mean tendon thickness (anterior to posterior [AP]) was 5.7 ± 2.9 mm. The mean tendon width (medial to lateral [ML]) was 7.1 ± 2.2 mm. The mean tendon length was 13.1 ± 8.7 cm. The mean footprint height (AP dimension) was 12.1 ± 2.9 mm, and mean footprint width (ML dimension) was 17.3 ± 7.1 mm. The mean distance between the AM footprint and the most medial aspect of the conjoint tendon footprint was 8.5 ± 4.2 mm. Tendon measurements demonstrated a considerable degree of both intra- and interspecimen variability. Conclusion: The AM tendon is consistently present just medial to the conjoint tendon at the ischial tuberosity, representing the lateral-most portion of the AM muscle. This study found wide variation in the dimensional characteristics of the AM tendon between specimens. Its shape and location can mimic the appearance of an intact hamstring (conjoint or semimembranosus) tendon intraoperatively or on diagnostic imaging, potentially misleading surgeons and radiologists. Therefore, detailed knowledge of the AM tendon anatomy, footprint anatomy, and its relationship to the hamstring muscle complex is paramount when planning surgical approach and technique. Clinical Relevance: The reported data may aid surgeons in more accurate recognition, diagnosis, and repair of proximal hamstring avulsion injuries.

Study Design Retrospective study. Objective This study reviews 1,768 consecutive cervical decompressions with or without instrumented fusion to identify patient-specific and procedural risk factors significantly correlated with the development of delayed cervical palsy (DCP). Methods Baseline demographic and procedural information was collected from the electronic medical record. Particular attention was devoted to reviewing each chart for recognized risk factors of postsurgical inflammatory neuropathy: autoimmune disease, blood transfusions, diabetes, and smoking. Results Of 1,669 patients, 56 (3.4%) developed a DCP. Although 71% of the palsies involved C5, 55% of palsies were multimyotomal and 18% were bilateral. Significant risk factors on univariate analysis included age ( p = 0.0061, odds ratio [OR] = 1.07, 95% confidence interval [CI] 1.008 to 1.050), posterior instrumented fusion ( p < 0.0001, OR = 3.30, 95% CI 1.920 to 5.653), prone versus semisitting/sitting position ( p = 0.0036, OR = 3.58, 95% CI 1.451 to 11.881), number of operative levels ( p < 0.0001, OR = 1.42, 95% CI 1.247 to 1.605), intraoperative transfusions ( p = 0.0231, OR = 2.57, 95% CI 1.152 to 5.132), and nonspecific autoimmune disease ( p = 0.0107, OR = 3.83, 95% CI 1.418 to 8.730). On multivariate analysis, number of operative levels ( p = 0.0053, OR = 1.27, 95% CI 1.075 to 1.496) and nonspecific autoimmune disease ( p = 0.0416, OR 2.95, 95% CI 1.047 to 7.092) remained significant. Conclusions Although this study partially supports a mechanical etiology in the pathogenesis of a DCP, we also describe a notable correlation with autoimmune risk factors. Bilateral and multimyotomal involvement provides additional support that some DCPs may result from an inflammatory response and thus an underlying multifactorial etiology for this complication.

Over the last decade, the mechanism of formation of intraneural ganglion cysts has been established through a meticulous review of clinical findings and correlation with patterns produced on magnetic resonance imaging (MRI). Pathognomonic imaging patterns distinguish these rare lesions from the more common extraneural variants in almost all cases. In this report, we present a new pattern of cyst occurrence in the subparaneurial compartment of the nerve and provide potential anatomic explanations for its pathogenesis. Using an anatomic framework of connective tissue compartments of the nerve, we reviewed 63 (56 fibular and seven tibial) intraneural ganglion cysts in the knee region evaluated at our institution and all reports with MRI in the world's literature for evidence of cyst occurrence in the subparaneurial compartment. We identified six cases (five in the common fibular nerve and one in the tibial nerve) at our institution that had MR evidence of cyst in the subparaneurial compartment with a new complex lobulated pattern. All cases had articular branch connections to the superior tibiofibular joint, which at operation were resected along with the joints. Follow‐up revealed complete recovery in all instances and no clinical or radiological signs of recurrence. Three cases out of 80 in the literature exhibited the new complex lobulated MRI pattern. We present a new pattern of intraneural ganglion cyst occurrence in a potential space that surrounds peripheral nerves‐ the subparaneurial compartment. We believe that the unifying articular theory applies to the pathogenesis and management of these rare variants. Clin. Anat. 29:530–537, 2016. © 2015 Wiley Periodicals, Inc.

Background Noonan syndrome with multiple lentigines (NSML), formerly known as LEOPARD syndrome, is an autosomal-dominant disorder characterised by lentigines, EKG abnormalities, ocular hypertelorism, pulmonic stenosis, abnormal genitalia, growth retardation and deafness. There is significant clinical overlap between NSML and other disorders that result from dysregulated rat sarcoma/mitogen-activated protein kinase pathway (RASopathies). Except for neurofibromatosis type 1, other RASopathies are not known to be typically associated with neurogenic tumours. Methods and results We evaluated patients from three families with pigmentary skin lesions, progressive neuropathy, enlarged nerves, massive burden of paraspinal tumours (neurofibroma was confirmed in one patient) and a clinical diagnosis of NSML. All patients had a mutation in the protein tyrosine phosphatase catalytic domain of the PTPN11 gene; two unrelated patients had the p.Thr468Met mutation, while the family consisting of two affected individuals harboured the p.Thr279Cys mutation. Molecular analysis performed on hypertrophic nerve tissue did not disclose a second somatic hit in NF1, PTPN11, NF2 or SMARCB1 genes. Conclusions Neurogenic tumours and hypertrophic neuropathy are unusual complications of NSML and may be an under-recognised manifestation that would warrant surveillance. Our observation may also have implications for other disorders caused by RAS-pathway dysregulation.