Sensory recovery after forearm median and ulnar nerve grafting

Median and ulnar nerve injuries are common, whether isolated or combined injury of both nerve. A nerve graft, if performed in a tensionless manner, has been shown to generally have better results than an end-to-end approximation performed under tension.

The aim of this study is to analyze the long-term results of sensory recovery after secondary reconstruction median and ulnar nerve by autograft in patients who were treated on Clinic for Plastic and Reconstructive Surgery in the period from January 1st 1993 to December 31st 2005. We analyzed the influence of the patients age, level of injury, the size of the graft and the period between the injury and operation on the late results.

Evaluation was performed in 55 patients with adequate follow-up. The mean follow-up period was 3.9 years. Reconstructions were applied on the median nerve in 31 patients and ulnar nerve in 24 patients. Criteria for inclusion in the study was median and ulnar nerve grafting in the forearm region. Patients were divided by age in two groups, below 25 and over 25 years, by injury level in the distal and proximal forearm injuries, by the length of autograft up to 5 cm and other group with graft length over 5 cm, by the period between injury and operation in group with denervation time up to 6 months and the group with denervation time over 6 months. Rating of sensibility was presented on the Highet Scale as modified by Dellon and more precise rating of sensibility was presented by Moberg's rating scale of sensibility. Calculation of frequencies and percentual values was performed for all included variables. For establishment of differences between the frequencies the /2-test was used (Chi square test) at the level of statistical importance (p < 0.05) with contingency tables.

We analyzed the results of reconstruction of median and ulnar nerves with respect to factors affecting functionally the result of operation, which are age, injury level, graft length and denervation time. We had 31 patients with median nerve grafting and we achieved sensory recovery S4 in 3 (10%) patients, S3+ in 9 (29%) patients, S3 in 8 (25.5%) patients, 52 in 9 (29%) patients and S2 in 2 (6.5%) patients. We had 24 patients with ulnar nerve grafting and we achieved S4 sensory recovery in 2 (8.5%) patients, S3+ in 6 (25%) patients, 53 in 5 (21%) patients, S2 in 10 (41%) patients and S2 in 1 (4%) patient. There was not significant difference in sensory recovery of median and ulnar nerve (chi-square = 1.00; df = 4; p = 0.909). There was not statistically significant difference by age and level of injury. The results were significantly better in patients with short grafts than in long ones (chi-square = 12.6; df = 4; p = 0.014) and in patients who had undergone surgical repair within 6 months (chi-square = 10; 2 df = 4; p = 0.038).

There was not significant difference in sensory recovery of median and ulnar nerves. The graft length and denervation time significantly influenced the functional outcome in sensory recovery. Mechanism of injury impacted on the results. Two point discrimination testing using a paperclip is a cheap, easily and quickly performed reproducible test of tactile gnosis, and should be included in nerve assessment protocols. We recommended using Moberg's rating scale for further research.