Comparing the results of leaving a 15-mm nerve gap with those of interposition graft in the sciatic nerves of rats, Scherman et al of Sweden found no difference. We carried out a similar study on 10 blue monkeys to see if equivalent results were obtained in primates.

We resected 15 mm of the radial nerve in the left brachium through an anterolateral approach. In five monkeys the nerve gap was bridged with an interposition nerve graft sutured with 8/0 Prolene(. In the other five, the gap was traversed by six longitudinal sutures of 6/0 Vicryl(, resulting in 12 strands. The upper limbs were immobilised in fibreglass casts for six weeks. After six months we killed the monkeys and harvested the nerve, which was evaluated histologically in terms of organisation at the repair site, fibrotic reaction at the repair site, and the ratio of number of axons proximal and distal to the repair site.

With both techniques, axonal growth across the gap averaged about 70%. The longitudinal gap sutures had slightly poorer organisation, with more tissue reaction.

Our results agree with Scherman et al’s findings that there is little difference in the results of the two methods, and suggest that a simple substrate will support nerve regeneration.