The Quality and Extension of Nerve Fibre Regeneration in the Centrocentral Anastomosis of the Peripheral Nerve

Summary

Centro central anastomosis (CCA) is the connection created by means of a nerve autograft placed between the fascicles of the proximal stump of a sectioned nerve. We have used this technique in the laboratory and in the human to avoid the formation of a terminal neuroma after amputation of a limb. The aim of the present study is to know what is the quality and how long is the progression of the regenerating nerve fibers coming from a fascicle and growing inside the nerve graft and into the other central fascicle.

56 male, adult, Sprague-Dawley rats were operated on. The 4 rats of Group I were used for control: the right sciatic nerve was exposed and dissected in its four branches. One piece of 10 mm was taken of each of the sural and the peroneal branches for hystological and hystomorphometric studies. In the 16 rats of Group II, after the section of the sural and peroneal branches a terminoterminal suture between their proximal stumps was made. In the 16 rats of Group III a CCA with an interposed nerve graft of 7 mm was achieved. 5,5 and 6 rats of Groups II and III were sacrified at 10, 40 and 365 days after the operation and the entire graft was taken for histological analysis. In the 20 rats of Group IV, 60 days after CCA, the graft was sectioned at its center to produce wallerian degeneration of nerve fibers. 10 days after this second operation the animals were sacrified and the nerve specimens were taken for histological study.

The histological and morphometric examination showed that the terminoterminal suture between the central fascicles does not avoid the neuroma. The CCA avoids the neuroma and the interposed graft reaches an almost orthotypic miscroscopic and morphometric structure. In the Group IV we noted that the regenerative sprouting is arrested inside the graft and the wallerian degeneration does not extend beyond the second suture, even though it is permeable.

The axonal regenerative sprouting inside the graft produces an orthotypic reconstruction of the peripheral nerve without a significant neuroma but the nerve fibers do not progress beyond the suture between the graft and the other central nerve stump. The speculative causes of this arrested growth are discussed.