Source of nerve autografts in clinical surgery: Technic for their suture

Abstract

T HERE is ample evidence to show that the most favorable type of graft for the repair of a nerve defect is the autograft. It is true that in the experimental animal good functional recovery may occur following the use of homografts that are fresh, stored in saline solution, Ringer’s solution9 or serum, or even fixed in formalin.r3 But the incidence of failure of such grafts is too great to risk their use in man.r0~12 Satisfactory results have been reported with dehydrated nerve grafts in the experimental animaP4 but results obtained from their clinical use have not yet been published. There is no doubt that autografts are more successful in the experimental animal than homografts.13 Moreover, there is some indication from our experimental work that cable grafts are superior to single thick grafts for the repair of defects in large nerves. The strands of the former are more readily vascularized and necrosis within the graft is less apt to occur. As a matter of fact, single autografts could not be used for the repair of defects in the major nerves in man inasmuch as there is no justification for sacrificing one major nerve for another unless there existed the unusual circumstance in which the nerve to be employed as the graft were from an amputation stump or otherwise of little or no use to the patient. The use of autografts presents two important advantages over homografts. First, one would thereby avoid blood group incompatibility, a possible factor in accounting for the necrosis of homografts. Second, one would eliminate acquired active immunity of host to homograft tissue which may be responsible for the disma1 results obtained with nerve homografts just as it seems to explain the destruction of skin homografts.3 Davis, Perret and Carroll’ have expressed the opinion that cable grafts, in which thin nerves are used to form a cable the caliber of the nerve to be repaired, are “doomed to failure because of the technical difficulties of suture.” It is true that the use of any form of thread (silk, wire, etc.) for the purpose of suturing a cable graft results in considerable damage to the strands of the graft and, all in all, very unsatisfactory unions. However, the recent introduction of plasma clot for the purpose of forming and suturing a cable graft13 makes it possible to circumvent these “technical difficulties of suture” and places the use of cable grafts on the agenda of the day. Davis and his associates consider that “it is the homogenous type of graft which is most applicable in Army general hospitals which are amputation as well as neurosurgical centers.” However, experimental and clinical experience weighs heavily against this recommendation. Granted then that the autograft alone should be employed the question arises as to which nerves should be sacrificed for use as grafts. It has been demonstrated that functional efficiency after regeneration of nerves depends to some extent upon the fibers attaining a size which approximates their normal diameters.’ If the size of the Schwannian tubes of the nerve graft strictly limits the caliber of the downgrowing axis cylinder, one might conclude that grafts taken from sensory nerves would be unsuitabIe for the repair of motor nerves since they contain fewer large nerve fibers and Schwannian tubes than the Iatter. (Figs. I and 2.) It is known, for