Optimizing donor fascicle selection in Oberlin's procedure: A retrospective review of anatomical variability using intraoperative neuromonitoring.

BACKGROUND: Transfer of the fascicle carrying the flexor carpi ulnaris (FCU) branch of the ulnar nerve (UN) to the biceps/brachialis muscle branch of the musculocutaneous nerve (Oberlin's procedure), is a mainstay technique for elbow flexion restoration in patients with upper brachial plexus injury. Despite its widespread use, there are few studies regarding the anatomic location of the donor fascicle for Oberlin's procedure. Our report aims to analyze the anatomical variability of this fascicle within the UN, while obtaining quantifiable, objective data with intraoperative neuromonitoring (IONM) for donor fascicle selection. METHODS: We performed a retrospective review of patients at our institution who underwent an Oberlin's procedure from September 2019 to July 2023. We used IONM for donor fascicle selection (greatest FCU muscle and least intrinsic hand muscle activation). We prospectively obtained demographic and electrophysiological data, as well as anatomical location of donor fascicles and post-surgical morbidities. Surgeon's perception of FCU/intrinsic muscle contraction was compared to objective muscle amplitude during IONM. RESULTS: Eight patients were included, with a mean age of 30.5 years and an injury-to-surgery interval of 4 months. Donor fascicle was located anterior in two cases, posterior in two, radial in two and ulnar in two patients. Correlation between surgeon's perception and IONM findings were consistent in six (75%) cases. No long term motor or sensory deficits were registered. CONCLUSIONS: Fascicle anatomy within the UN at the proximal arm is highly variable. The use of IONM can aid in optimizing donor fascicle selection for Oberlin's procedure.

Delayed Tetraplegia After Thoracolumbar Scoliosis Surgery in Stuve-Wiedemann Syndrome.

OBJECTIVE: We present 2 patients with Stuve-Wiedemann syndrome (SWS) who suffered delayed tetraparesis following posterior spinal surgery for scoliosis. BACKGROUND SUMMARY: Delayed tetraparesis after a syndromic thoracic scoliosis correction has never been reported. A cord injury distant from the surgical site is rare, and intraoperative neuromonitoring should be used to detect and prevent neurologic impairment. METHODS: Review of medical charts. RESULTS: Two patients with SWS suffered delayed tetraparesis 20 and 40 hours respectively after thoracolumbar posterior surgery. In one patient distal motor evoked potentials fell and recovered partially during surgery. In both patients, early postoperative neurologic examination was normal (in one of them except for the extensor hallucis 2/5). CT scan showed correct instrumentation placement and no compressive haematoma. MRI ruled out cord anomalies, but revealed in both patients identical cervical edema that was most likely secondary to ischemia. Angiogram revealed an absence of anterior cord vascular supply. CONCLUSIONS: Correction of severe deformities in syndromic patients may lead to stretch injuries of the spinal cord and its vascular supply. This in turn may lead to a neurological deficit extending beyond the limits of the spinal instrumentation. Abrupt postoperative neck pain may be an alert to this impending development. Close surveillance in the early postoperative period should be maintained in patients with SWS because a delayed neurological deficit can be present even hours afterwards and may be cranial to the surgical level.