[Nerve Tubes for the Repair of Traumatic Sensory Nerve Lesions of the Hand: Review and Planning Study for a Randomised Controlled Multicentre Trial]. / Nervetubes zur Versorgung von traumatischen sensiblen Nervenläsionen der Hand - Übersicht sowie retrospektive Planungsstudie für eine randomisiert-kontrollierte multizentrische Studie.

ABSTRACT

BACKGROUND: Nerve tubes are used for bridging of short nerve gaps and for coating of primary end-to-end nerve sutures. This article provides an overview of available implants and their application. Also it presents a retrospective planning study aiming to determine the static 2-point discrimination after primary peripheral nerve repair with and without the use of a nerve tube. The results have been used to determine the sample size of a prospective randomised trial. PATIENTS AND METHODS: 54 peripheral nerve injuries of 41 patients were treated by primary end-to-end nerve sutures with or without the additional use of a nerve tube (n=28 and n=26, respectively). 38 digital nerves and 16 median and ulnar nerves were affected. Nerve tubes were used for the repair of 15 digital nerves and 13 median and ulnar nerves. Clinical follow-up was performed 46 months after surgery (patients without nerve tubes) and 18 months after surgery (patients with nerve tubes), respectively. Static 2-point discrimination (2PD) was measured by double-tip compasses (weight 18 g) and patients were examined for clinical signs of neuroma. Further examinations included grip strength as a percentage value compared with the uninjured hand and, in case of finger injuries, the range of motion in the proximal and distal interphalangeal joints, Strickland score, DASH score and implant-associated complications. RESULTS: In patients with primary end-to-end sutures for finger injuries, there were no statistically significant differences between treatment with and without nerve tubes regarding 2PD, grip strength, DASH- or Strickland score. However, 2PD values of patients with nerve tubes had an increased spread. Average 2PD in digital nerves was 4.5 mm (3-15; SD 3.9) without nerve tubes and 5.5 mm (3-15; SD 5) with nerve tubes. Average 2PD after lesions of the median and ulnar nerves was 10 mm (3-15; SD 5.9 and 5.4, respectively) in both groups. CONCLUSION: The additional use of a nerve tube showed no superiority in this planning study. The expected average 2PD is 5 mm after digital nerve injuries and 10 mm after lesions of the median or ulnar nerves.