TOPOGRAFÍA INTRANEURAL DE LA RAMA PROFUNDA DEL NERVIO ULNAR EN EL ANTEBRAZO DISTAL: ESTUDIO CADAVÉRICO. Intraneural topography of the deep branch of the ulnar nerve in the distal forearm: cadaveric study.

Objetivo: estudiar la topografia intraneural de la rama profunda del nervio ulnar (RPNU) en el antebrazo distal en vistas a su identificacion mediante diseccion intraneural minima durante la transferencia del nervio del pronador cuadrado (NPC) a la RPNU. Materiales y metodos: En 15 antebrazos cadavericos se fijo el paquete vasculonervioso ulnar a los planos musculares profundos cada un centimetro tomando como referencia el hueso pisiforme. Se diseco en sentido proximal la RPNU bajo microscopio quirurgico (Olympus OME, 4-20x) y se registro su posicion intraneural en base a una division en cuadrantes. Se midio la distancia desde el origen de la rama cutanea dorsal (RCD) del nervio ulnar al pisiforme y se registro su relacion intraneural con la RPNU. Resultados: La RPNU se individualizo hasta 69mm (41-94) proximal al hueso pisiforme, ubicandose en el cuadrante posteromedial del nervio ulnar en el 78% (67-87), el 93% (92-93) y el 100% de los casos entre los 0-2, 3-6 y 7-9 centimetros, respectivamente. La distancia pisiforme-RCD fue de 63mm (52-83). En 11 miembros la diseccion de la RPNU se extendio proximalmente al origen de la RCD, ubicandose siempre entre esta ultima y la rama superficial del nervio ulnar. Conclusiones: La topografia intraneural de la RPNU en el sitio optimo para su seccion en vistas a su anastomosis con el NPC es predecible en la mayoria de los casos, lo que confirma la viabilidad de su identificacion precisa mediante diseccion intraneural minima.  Objective: to assess the intraneural anatomy of the deep branch of the ulnar nerve (DBUN) in the distal forearm in reference to its identification by means of minimal intraneural dissection during pronator quadratus nerve to DBUN transfers. Materials and methods: In 15 cadaveric forearms the ulnar neurovascular bundle was identified and attached to the subjacent muscles every one centimeter. Pisiform bone was used as reference. Intraneural proximal dissection of the deep branch of the ulnar nerve was performed under magnification (Olympus OME, 4-20x) and its intraneural position was registered using a quadrants scheme. Distance from pisiform to the origin of the dorsal cutaneous branch of the ulnar nerve (DCB) was measured and its intraneural position relative to DBUN was identified. Results: The DBUN could be identified up to 69mm (41-94) proximal to the pisiform and occupied the posteromedial quadrant of the ulnar nerve in 78% (67-87), 93% (92-93) and 100% of the cases in the 0-2, 3-6 and 7-9cm ranges, respectively. Distance from pisiform to the origin of the DCB was 63mm (52-83). The DBUN could be identified proximal to the origin of the DCB in 11 forearms, being located between the latter and the superficial branch of the ulnar nerve in all this cases.  Conclusions: Intraneural topography of the DBUN in the most appropriate site for its identification during its anastomosis to the PQN is predictable in the majority of cases, which supports the viability of safe identification of the de DBUN by means of minimal intraneural dissection.