[Anastomosis of hypoglossal-facial nerves by modified May technique]

Facial palsy is a unpleasant disorder, which handicaps habitual vital movements and the expression of the face. There are many surgical techniques, which use the neighboring nerve fibers to reanimate the face, such as the end to end or side to end anastomosis with hypoglosal, glosopharyngeal, axesorius, or mandibular nerves. The donor fiber can be derived from homolateral or heterolateral side. The reconstruction can be completed by cosmetic surgery using parietal muscle or free muscular flaps. The authors wanted to present the modified May technique described by Darrouzet with the rerouting of the facial nerve in the mastoid portion of the temporal bone. This procedure aimed at elongation of the facial nerve stumps with simultaneous rerouting of the facial nerve. Three temporal bone blocks with adjacent tissues were taken from cadavers. The temporal bones were dissected under operating microscope ZEISS OPM 11. The standard set of instruments for the ear microsurgery was used. As the first step retroauricular incision and large antromastoidectomy were performed. The facial nerve was found and exposed in its mastoid portion, then rerouted out of the temporal bone. The length of the isolated nerve stump was measured. The photos were also taken as documentation. The length of the prolonged nerve stump was 13 mm in each case. After adding to this value the length of the trunk, i.e. the portion between stylomastoid foramen and pes anserinus, the fragments of rerouted nerve were elongated up to 21 mm. This distance allowed for performing the facial-hypoglosal anastomosis using only one neuroraphy without increased tension.