Ulnar nerve transposition in the hand: a cadaveric study

Abstract

Primary repair of a nerve is preferable over nerve grafting when a tension-free environment can be achieved. The purpose of this cadaveric study was to evaluate the facility of nerve-gap closure gained by removing the hamate hook, eliminating the circuitous path of the motor branch of the ulnar nerve in the hand. Six cadaveric specimens were dissected and the length of the motor branch coursing through Guyon’s canal before and after hamate hook excision and nerve transposition was recorded. Average length was significantly shorter in specimens after transposition, with a mean 21% reduction relative to the nerve’s original course. This knowledge may help guide surgeons on whether excision of the hamate hook will allow for primary repair of the nerve when a segmental defect or retraction and scarring of the nerve stumps is encountered.

Outcomes of radiocarpal pinning to facilitate nerve repair in wrist-level ulnar nerve injuries with defect

“…The ideal scenario for nerve repair is to achieve tension-free end-to-end neurorrhaphy. 8,9,17 However, this could be complicated by soft tissue loss, scarring, and neuroma formation, inevitably creating a nerve defect. The current strategies for managing nerve defects include positional adjustment, nerve transposition or rerouting, nerve grafting with various choices in graft selection, nerve transfer, and perhaps tendon transfer in more chronic cases.…”

“…[3][4][5][6][7] Furthermore, a direct end-to-end nerve repair is preferred over nerve grafting when a tension-free environment can be achieved. 8,9 However, in cases of delayed repair or inadequate primary repair, a neuroma may develop, causing pain, and nerve conduction block. Neuroma excision results in a nerve gap, making end-to-end neurorrhaphy more challenging.…”

Síndrome del canal de Guyon con compresión motora del nervio ulnar

“…Este cuadro clínico, esta causado por la compresión del nervio ulnar durante su paso por el canal de Guyon, puede general síntomas sensitivos y motores en la mayoría de los casos. Es poco habitual que se genere síntomas motores aislados o sensitivos aislados, sin embargo estos se pueden dar dependiendo de la localización de la lesión (7).…”

“…Dos estudios hallaron anomalías musculares entre un 22% a un 53% en el canal de Guyon, respectivamente en la muñeca. Uno de los estudios también encontró hueso Ganchoso hipoplásico en un 2%, múltiples ramas del nervio ulnar en un 30% y aumento del tejido graso dentro del canal de Guyon en un 12% (7,12). (5).…”

“…El cuadro clínico de esta patología puede variar, el diagnostico clínico no siempre es sencillo de realizar, principalmente en casos en los cuales los síntomas sensitivos son atípico o están ausentes (7). El diagnóstico está basado principalmente en una buena historia clínica detallada del paciente, realizar un examen físico minucioso y utilizar los estudios de imágenes complementarios de forma correcta (17).…”