The best method to restore continuity of the transected peripheral nerve is the primary end-to-end repair [1]. In cases of direct loss or degeneration of the neural tissue due to blunt, crush, or avulsion injury, a gap is created between the nerve ends. If the gap is relatively small (does not exceed 2.5 cm), both nerve trunks can be mobilized to perform end-to-end coaptation [2]. In larger defects, stretching of the nerve ends can cause ischemia and regeneration failure, therefore the dogma is: to repair nerves without tension [3]. If direct nerve coaptation is impossible, the method of choice for nerve reconstruction is engraftment of the autologous nerve material, to replace the missing fragment.

In 1870 Philipeaux and Vulpian, the pioneers of nerve grafting, reported the first successful experimental approach [4]. Later, in 1885, Albert was the first who used nerve graft in clinic [5]. During the first and the second World War, enthusiasm for the method of nerve repair using grafts gradually decreased, as a consequence of unsatisfactory results attributed to poor surgical technique, high infection rate, and inadequate knowledge of nerve internal and topographical anatomy [6]. The resurrection of the idea of nerve grafting took place in 1947 when Seddon popularized the method of cable grafting [7]. Introduction of microsurgical techniques in 1950s by Millesi [8], compiled with the results of Suderland’s study on intraneural anatomy of the peripheral nerves [9], and revolutionized the approach for peripheral nerve grafting. Free nerve autograft repair technique became the gold standard in gap management. Despite the fact that nerve autograft technique is commonly used for over 50 years, some questions still arise. The questions are about best timing for nerve grafting, and the best method for graft coaptation. The concept of “restitutio ad integrum” was based on the restoration of the “close to normal” nerve architecture with the graft material. The cable graft technique used as a standard provided “enough” of the graft material to cover the cross section area of the severed nerve. The question, however, which has not been clearly answered, is how much of the graft material is “enough” for optimal nerve regeneration? Should the repaired nerve be fully covered with the graft, or maybe only partial coverage of cross-sectional nerve area is sufficient for the propagation of regeneration from the proximal to the distal nerve segment. This question is of great importance if we take under consideration limited sources of neural tissue accessible for harvesting, and the large amount of grafts needed in case of extensive trauma. Intrigued by the reports, that major nerves repaired with “inadequate” diameter of the graft cables resulted with surprisingly good functional recovery – we have raised the following question. Could the single fascicle of the peripheral nerve serve as a functional conduit and provide adequate nerve regeneration during nerve gap repair? This approach might also have the potential to decrease morbidity related to multiple sites of nerve harvest. To test this hypothesis we have developed rat animal model of single fascicle sciatic nerve grafting. This model enables the use of different size fascicles as grafts, covering 50 and 25 % of the total cross sectional area of the nerve stumps during gap reconstruction.