The use of vein or muscle grafts to bridge nerve defects longer than 1-1.5 cm gives poor results. Veins collapse and in muscle grafts axons may regrow outside the graft. We used veins (to guide regeneration) filled with muscle (to avoid vein collapse). Nerve regeneration through 1 and 2 cm grafts made of vein plus muscle was compared with similarly long traditional nerve grafts, free fresh muscle grafts, and empty vein grafts. Regeneration was assessed clinically and histologically (qualitative and quantitative evaluation) in the graft and distal nerve stumps. Vein plus muscle grafts were superior to vein and fresh muscle grafts both functionally and histologically. Functional results were similar to those found in traditional nerve grafts, but axon number was superior in the veins filled with muscle. This suggests that vein filled with muscle might serve as a grafting conduit for the repair of peripheral nerve injuries and could give better results than traditional nerve grafting.

A considerable amount of research is being undertaken regarding the possibility of bridging loss of nerve substance with different guiding tubes, in order to improve functional outcome, reduce the surgical time, and reduce damage at donor nerve sites. A review of the literature and personal research allows us to state that: for short gaps, biological tubes (autologous veins) may give good results and also allow chemotactic attraction with selective arrangements of motor and sensory axons. Gaps longer than 1 cm do not allow tropism and are associated with failure to support axonal regrowth. Artificial biodegradable conduits still show results that are controversial; they may give good results provided that the material of which they are made is perfectly tolerated. Empty tubes, longer than 8-10 mm, besides being deprived of the chemotactic attraction, may collapse or be partially reabsorbed and replaced by scar. Probably in the near future biological or biodegradable tubes, containing laminin-like substances or muscle scaffold, will allow us to bridge increasingly large defects in nerves.

Common peroneal nerve palsy has been reported to be the most frequent lower extremity palsy characterized by a supinated equinovarus foot deformity and foot drop. Dynamic tendon transposition represents the gold standard for surgical restoration of dorsiflexion of a permanently paralyzed foot. Between 1998 and 2005, we operated on a selected series of 16 patients with traumatic complete common peroneal nerve palsy. In all cases, we performed a double tendon transfer through the interosseous membrane. The posterior tibialis tendon was transferred to the tibialis anterior rerouted through a new insertion on the third cuneiform and the flexor digitorum longus was transferred to the extensor digitorum longus and extensor hallucis longus tendons. All 16 patients were reviewed at a minimum followup of 24 months (mean, 65 months; range, 24-114 months). The results were assessed using the Stanmore system questionnaire and were classified as excellent in eight, good in five, fair in two, and poor in one. Postoperative static and dynamic baropodometric evaluations also were performed. The proposed procedure, which provides an appropriate direction of pull with adequate length and fixation, is a reliable new method to restore balanced foot dorsiflexion correcting the foot and digit drop and producing a normal gait without the use of orthoses.

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