The procedure is done under general anesthesia because two operating fields (one at the upper and one in the lower extremity) exist concomitantly. The standard approach used for the primary operation is used also for the revision surgery with the difference that the incision needs to be extended both proximally and distally because the compressed nerve must be exposed first in an unscarred tissue environment. The median or ulnar nerve is identified and separated from the surrounding scar tissue. This dissection is done under 3.5-loupe magnification. With the use of an operating microscope for better magnification and visualization internal neu-rolysis is performed if severe scarring and compression extends into the fascicles. The nerve fascicles are freed from the scar tissue and unobstructed nerve excursion is obtained.
The greater saphenous vein is harvested from the ipsilateral or the contralateral lower extremity. The incision is made longitudinally 1 cm anterior to medial mal-leolus. Usually a vein length of 25-30 cm is needed and the incision is made accordingly. The required length is three to four times the length of the nerve segment that
is going to be wrapped. Care is taken to avoid injury of small nerves and other vein branches. After the saphenous vein is harvested, it is incised and opened longitudinally (Fig. 3.1). One of the ends of the vein graft is tacked distal to the scarred portion of the nerve, on a tissue that is not mobile, with the intima against the nerve, using a 7-0 or 8-0 nylon stitch. The wrapping proceeds circumferentially as described by Masear at al.1 from distal to proximal (Figs. 3.2 and 3.3). After each complete circle of the vein on the nerve the vein is stabilized with a loose 7-0 or 8-0 nylon stitch to the adjacent ring of vein (Fig. 3.4). The other end of the vein graft is tacked proximal to the scarred segment of the nerve, on unscarred epineurium (Fig. 3.5). It is important to cover completely the scarred segment of the nerve because this may cause scarring again as Masear and Colgin6 reported in their series.
Postoperatively, for the median nerve, the wrist is immobilized for one week, in slight extension. For vein wrapping of the ulnar nerve the elbow is not immobilized.
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