Maldonado, Andrés A.

Despite advances in imaging, instrumentation, surgical techniques, and postoperative care, outcomes for certain peripheral nerve procedures remain consistently disappointing. In this article, we describe five surgical scenarios--adult pan-brachial plexus injuries, peroneal nerve injury after knee dislocation, sciatic nerve injury after total hip arthroplasty, radiation-induced brachial plexopathy, and lower trunk injury after cardiac surgery--that, in our experience and review of the literature, frequently lead to limited and consistently poor functional recovery after nerve surgery. These challenging cases reflect not only technical and anatomical complexity but the profound biological limitations of nerve regeneration in specific contexts. By critically analyzing these five procedures, we aim to promote more realistic patient counseling, support timely and individualized decision-making, and foster a more nuanced understanding of when and what type of surgical intervention may or may not be beneficial.

ABSTRACT Iatrogenic spinal accessory nerve (SAN) injuries can occur as complications of posterior triangle of the neck surgery, resulting in lateral scapular winging and a shoulder droop. Rarely has this complication been described after a cosmetic rhytidectomy (face‐lift procedure). Here, we present two cases of iatrogenic SAN injuries that occurred after cosmetic rhytidectomies. The use of electrodiagnostic and ultrasound examinations provides invaluable information to assess peripheral nerve injuries. Electrodiagnostic testing can confirm the presence and severity of the injury, while ultrasound can provide additional anatomical information and direct visualization to confirm the continuity of the nerve and assess muscle denervation changes.

ABSTRACTPrimary lymphedema (i.e., a chronic condition characterized by the accumulation of protein‐rich fluid in the interstitial spaces due to impaired lymphatic drainage) and lipomatosis of nerve (LN) (i.e., a congenital lesion characterized by the presence of fat interspersed within nerve) can involve a significant overgrowth of the affected limb, but their pathophysiology and treatment are totally different. This report addresses the misdiagnosis of both entities. The purpose is to highlight how both entities can be differentiated through two case reports. The first patient, a 69‐year‐old man, presented in our lymphedema clinic with multiple debulking operations; he was diagnosed with right upper extremity lymphedema during childhood. The thumb, index, and middle fingers had previously been amputated due to sequelae from the bony overgrowth. MRI of the right upper extremity showed pathognomonic features of LN affecting the median nerve associated with soft tissue fatty overgrowth. He had a 3 months follow‐up for this condition in our institution during which his symptoms remained stable. The second patient, an 81‐year‐old man, presented in our lymphedema clinic. He carried a long time diagnosis of primary left lower extremity lymphedema and had been followed at our institution for more than 25 years. Physical examination revealed overgrowth (increased volume) affecting the entire leg and foot. MRI showed pathognomonic features of LN of the left sciatic nerve. No surgical interventions were performed. At the last follow‐up, his extremity showed slightly worsened diameter measurements. Based on our 2 cases presented and 2 additional cases identified in the literature, we believe that primary lymphedema and LN are two different entities that could be confused. Plastic surgeons treating patients with lymphedema should be aware of LN and rule out this condition clinically and with imaging (US or MRI).

BACKGROUND The articular origin of intraneural ganglion cysts has been previously described and well supported, except for the median nerve at the level of the elbow. OBSERVATIONS The authors present a patient with a median intraneural ganglion cyst at the elbow region and magnetic resonance imaging (MRI) evidence of a joint connection to the proximal radioulnar joint. A 63-year-old man presented with thumb flexion weakness and dysesthesias in the thumb, index, and middle fingers. Electromyography confirmed a median nerve lesion at the elbow. MRI demonstrated a median intraneural cyst as well as an extraneural cyst, both arising from the proximal radioulnar joint. The articular branch between the cyst and the proximal radioulnar joint was identified preoperatively on MRI and intraoperatively using indocyanine green. Following disconnection of the articular branch and pedicle and decompression of the intra- and extraneural cysts, the patient recovered grade M4 motor function after 6 months, with resolution of neuropathic pain immediately after surgery. LESSONS The authors present the first case of a median intraneural cyst with a joint connection to the proximal radioulnar joint. The authors believe that this report along with other historical data strengthens the articular theory for intraneural ganglion cysts not only at this site but at all sites. https://thejns.org/doi/10.3171/CASE24564

BACKGROUND The articular origin of intraneural cysts has been previously described and well supported. Intraneural ganglion cysts most commonly occur in adults and in the common peroneal nerve arising from the anterior aspect of the superior tibiofibular joint (STFJ). OBSERVATIONS The authors report a pediatric patient who developed a tibial intraneural cyst arising from the posterior aspect of the STFJ within months after surgical treatment of a peroneal intraneural cyst from the anterior aspect of the same joint. Surgery consisted of disconnecting the articular branch of the peroneal nerve and decompression of the cyst. Three-month postoperative magnetic resonance imaging showed resolution of the peroneal intraneural cyst and anterior compartment denervation but demonstrated a clinically occult small tibial intraneural ganglion cyst arising from the STFJ with popliteus muscle atrophy. LESSONS This case underscores the importance of addressing the underlying etiology (articular synovitis) or the communication pathways (articular branches) whenever feasible to mitigate intraneural cyst recurrence. Furthermore, this report reinforces the validity of the articular theory. https://thejns.org/doi/10.3171/CASE24277

BACKGROUND Lipomatosis of nerve (LN) is a rare disorder characterized by the massive enlargement of peripheral nerves, frequently accompanied by generalized fibroadipose proliferation and skeletal overgrowth. OBSERVATIONS The authors have been routinely following a 20-year-old male for lipomatosis of median nerve at the wrist noted shortly after birth. He had undergone resection of the lesion accompanied by sural nerve grafting at another institution. Clinically, although his neurological loss of function has been stable, he has had continued soft tissue growth. Serial magnetic resonance imaging has revealed persistent LN proximal to the repair sites with evidence of fatty proliferation in the sural grafts and continued LN and fatty proliferation distally. There has been a progressive circumferential pattern of fibrosis around the proximal and distal suture lines, which has a similar radiological pattern to desmoid type fibromatosis (a pattern recently described in neuromuscular choristoma [NMC] desmoid-type fibromatosis). LESSONS Considering the similar reaction of nerve in both LN and NMC despite differing genetic cascades, the authors believe a unifying process occurs in both lesions. The pattern of circumferential fibroproliferation would be most consistent with neuron-mediated growth from unspecified trophic factors, supporting a previously reported a nerve-derived “inside-out mechanism.” The clinical consequences of this unifying process are presented.

OBJECTIVE Neuromuscular choristoma (NMC) is a rare developmental malformation of peripheral nerve that is frequently associated with the development of a desmoid-type fibromatosis (DTF). Both NMC and NMC-DTF typically contain pathogenic CTNNB1 mutations and NMC-DTF develop only within the NMC-affected nerve territory. The authors aimed to determine if there is a nerve-driven mechanism involved in the formation of NMC-DTF from the underlying NMC-affected nerve. METHODS Retrospective review was performed for patients evaluated in the authors’ institution with a diagnosis of NMC-DTF in the sciatic nerve (or lumbosacral plexus). MRI and FDG PET/CT studies were reviewed to determine the specific relationship and configuration of NMC and DTF lesions along the sciatic nerve. RESULTS Ten patients were identified with sciatic nerve NMC and NMC-DTF involving the lumbosacral plexus, sciatic nerve, or sciatic nerve branches. All primary NMC-DTF lesions were located in the sciatic nerve territory. Eight cases of NMC-DTF demonstrated circumferential encasement of the sciatic nerve, and one abutted the sciatic nerve. One patient had a primary DTF remote from the sciatic nerve, but subsequently developed multifocal DTF within the NMC nerve territory, including 2 satellite DTFs that circumferentially encased the parent nerve. Five patients had a total of 8 satellite DTFs, 4 of which abutted the parent nerve and 3 that circumferentially involved the parent nerve. CONCLUSIONS Based on clinical and radiological data, a novel mechanism of NMC-DTF development from soft tissues innervated by NMC-affected nerve segments is proposed, reflecting their shared molecular genetic alteration. The authors believe the DTF develops outward from the NMC in a radial fashion or it arises in the NMC and wraps around it as it grows. In either scenario, NMC-DTF develops directly from the nerve, likely arising from (myo)fibroblasts within the stromal microenvironment of the NMC and grows outward into the surrounding soft tissues. Clinical implications for patient diagnosis and treatment are presented based on the proposed pathogenetic mechanism.

BACKGROUND AND IMPORTANCE: Snapping of the triceps muscle occurs when a portion of the medial head dislocates over the medial epicondyle with elbow flexion. Resection or redirection of a portion of the triceps muscle is the main surgical treatment. The extent of triceps resection/redirection is difficult to evaluate. A novel intraoperative technique, stimulating the musculocutaneous nerve, to simulate active elbow flexion is proposed to help ensure that the snapping triceps has been adequately treated. CLINICAL PRESENTATION: A patient presented with a several year history of bilateral elbow pain, snapping, and ulnar nerve (UN) paresthesias. Previous staged bilateral subcutaneous UN transpositions were performed at another institution for documented UN dislocation and neuritis. Postoperatively symptoms of painful snapping persisted. Bilateral snapping triceps was diagnosed. The left elbow was reoperated. Intraoperative electrical stimulation of the musculocutaneous nerve was performed to reproduce the snapping triceps. Activation of the biceps/brachialis muscles produced powerful elbow flexion, allowed direct visualization of the forceful snapping triceps, and helped assess the adequacy of muscle resection/redirection. CONCLUSION: Intraoperative biceps/brachialis stimulation can potentially help determine how much triceps muscle should be resected/redirected to treat patients with snapping triceps.

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: 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. Methods: 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. Results: 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 (P < 0.005). 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. Conclusions: 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. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.