The steps of the operation are practically as follows: Incision is made along the anterior margin of the mastoid and the sternomastoid muscle, and the parotid gland is retracted forward and the posterior belly of the digastric is exposed. It should then be pulled downward and backward and divided if necessary. The styloid process is identified, and the facial nerve which emerges from the stylomastoid foramen near its base is then sought and isolated. It should be separated as high as possible and divided close to its exit, so that one-half inch of its free trunk may be secured before it enters the gland. Two fine silk sutures are then passed, one on either side, through the peripheral end of its sheath and tied, the ends remaining long, to be subsequently used. This nerve end should be trimmed to a wedge shape. Next the transverse process of the atlas is identified and the deep cervical fascia divided. This will expose the internal jugular, which should be separated and held out of the way. There will now be seen the spinal accessory nerve, which runs obliquely downward and outward, sometimes in front of and sometimes behind the jugular ([Fig. 403]). When the vein is held forward and the fascia well retracted both the hypoglossal ([Fig. 404]) and the pneumogastric nerves are seen, with the internal carotid to their inner sides. The former may be identified either by the electric current, which will cause contractions in the muscles supplied by it, or it may be followed down to where it turns forward around the occipital artery and gives off the descendens noni. Here it should be separated until its trunk is sufficiently free, so that the facial stump can be inserted into it without tension. The nerve being elevated by a hook a slit is made in it, about ³⁄₄ inch long. Into this the wedge-shaped end of the facial trunk is introduced, and held there by utilizing the sutures which have already been passed through its sheath. When the nerve is thus firmly held in the cleft, with its end turned toward the direction of nerve supply, a little cargile membrane may be wrapped around the junction and the wound closed.[46]
[46] Taylor and Clark, New York Medical Record, February 27, 1904, p. 321.
Nerve regeneration has been known to follow this procedure in a number of cases, and it has given encouraging results. Considerable time, however, is required, and the patients should be warned that results are not to be quickly expected.
Fig. 403
Fig. 404
Exposure required for anastomosis of facial and spinal accessory nerves: a, facial nerve; b, sp. acces.; c, int. jug.; d, digastric muscle; e, atlas, trans. proc. (Marion.)
Exposure required for anastomosis of facial and hypoglossal nerves: a, facial nerve; b, sternomastoid; c, digastric; d, parotid; e, hypoglossal. (Marion.)