Refinements in the technique of ‘awake’ electrical nerve stimulation in the management of chronic low ulnar nerve injuries

Abstract

The standard technique in the management of chronic low ulnar nerve injuries includes excision of the neuroma and reconstruction using sural nerve grafts in the fully anaesthetised patient. It has been shown that using this standard technique, disappointing results may be observed and that significant improvement in results could be obtained if intra-operative matching of sensory and motor fascicles is performed. This study reports on eight patients with chronic ulnar nerve injuries managed using the technique of electrical fascicular orientation and sural nerve grafting. In all patients, intra-operative electrical stimulation of the fascicles in the proximal stump was done in the awake state. Several refinements in technique are described including detailing pre-operative patient education, anaesthetic considerations and in the technique of nerve dissection. Assessment was done using a sensory grading system mainly based on static two-point discrimination and a motor grading system based on intrinsic muscle function and key pinch power. At final follow up satisfactory sensory (S3+ or S4) and motor (M3 or M4) recovery was obtained in almost all cases. It was concluded that intra-operative electrical fascicular orientation was reliable and that our refinements in the technique ensured better communication with the patient during surgery, resulted in a smoother awakening without apprehension, and provided an easier nerve dissection with preservation of the blood supply of the distal nerve segment.