Microsurgery: Transplantation and Replantation by Harry J. Buncke, MD, et al.
  Table of Contents / Chapter 45:
Direct Surgery of Traumatic Lesions of the Brachial Plexus
 
  First, the brachial plexus is dissected and the lesions are precisely identified, keeping in mind that supraclavicular lesions often are in continuity; then plexus root trunks are sharply cut back to healthy neural tissue with the guillotine knife of Meyer. Nerve grafting is done according to the technique of Millesi.9,11 In the past few years, this technique has been modified by the use of biologic glues (Biocol and Tissucol).37 Formerly we used two or three stitches of 9.0 and 10.0 polypropylene monofilament to suture each fascicular group. This procedure was time-consuming and somewhat damaging to perineural and neural tissue.

Our experience of gluing nerve grafts showed that results thus obtained are significantly superior to those observed after conventional suturing; gluing facilitates abutment of the nerve substance; it also minimizes handling of the nerve ends, thereby reducing unwanted mushrooming.

Short grafts, 5 to 7 cm long, are used to repair the upper trunk; surrounding tissues have a favorable influence on graft revascularization, which is obtained in a few days. Conversely, extensive lesions necessitate long grafts, 10 to 15 cm, and the tissue environment is less favorable. In these cases, we prefer to use vascularized nerve grafts. The principle of vascularized graft was developed by Taylor for the repair of large losses of substance in peripheral nerves.38 Later, Comtet16 put into use the principle of vascularized transfer of the cutaneous antebrachii medialis nerve. Birch presented a large series of plexus brachial grafts using the vascularized ulnar nerve of the forearm.39 In our protocol, we use the ulnar nerve vascularized by the collateral proximal ulnar artery originating at the brachial artery. This donor site has the advantage of not interrupting the continuity of the principal vascular axis, as is the case when the forearm ulnar nerve is used. According to the work of Lebreton, the collateral proximal ulnar artery exists in 94% of the cases.40 The vascularized graft can be used as a free graft as well as a transposed local graft. The vascularization of the graft facilitates axonal progression. Within the first 6 months after vascularized grafting, progression of the Tinel sign averages 2 mm per day. Contractions of the biceps muscle appear about the ninth month. With conventional grafts, equivalent results are not seen before the twelfth month. We have observed, however, that results obtained with conventional grafts and with vascularized grafts tended to be similar in the long run. Nevertheless, we believe that results are more consistent after vascularized grafts, as long as there is no embolization of the anastomosis. In our series of 13 cases of vascularized grafts on the brachial plexus, seven were free grafts with arteriovenous anastomosis and six were pediculized grafts. The length of the free grafts varied from 12 to 18 cm; that of the pedicled grafts varied from 23 to 26 cm. We have observed three results at M4, six at M3+, two at M3-, and two at M2.

 

This technique, however, is of limited use because it implies the intradural avulsion of the C8 and T1 roots. Besides, in the event of thrombosis of the vascular anastomosis, results will be inferior to those of conventional grafts because the central part of the grafts will undergo necrosis.

Vascularized allografting is a way of getting around the problem of donor site scarcity but makes indispensable the use of immunosuppressant treatment. Studies made by Bour41 have shown that nerve regeneration is possible through vascularized allografts as long as cyclosporine is administered; interruption of the immunosuppressive treatment, however, brings about a deterioration of the graft and, consequently, of the functional condition. In the present state of experimental studies, use of these vascularized allografts is not justified because continuous postoperative immunosuppressive treatment is unacceptable in reconstructive surgery.

NEUROTIZATIONS

next page...

 
  2002 © This page, and all contents, are Copyright by The Buncke Clinic