The Cutting Edge: Surface Texture Analysis following Resection of Nerve Stumps Using Various Instruments

Preparation of nerve ends is an essential part of nerve repair surgery. Multiple instruments have been described for this purpose; however, no consensus exists regarding which is the least traumatic for tissue handling. We believe that various instruments used for nerve-end excision will lead to different surface roughness.

Median and ulnar nerves from fresh frozen cadavers were dissected, and 1-2 cm lengths were excised using a No. 11 blade, a razor blade, or a pair of scissors. Using electron microscopy, 3-dimensional surface analysis of roughness (Sa) for each specimen was performed using ZeeScan optical hardware and GetPhase software (PhaseView, Buisson, France). An ANOVA or Kruskal-Wallis test compared roughness measures among cutting techniques.

Forty nerves were included. Of these, 13 (32.5%) were cut using scissors, 15 (37.5%) using a razor blade, and 12 (30%) using a No. 11 blade. An ANOVA test showed statistical differences in Sa among the cutting techniques (P = 0.002), with the lowest mean Sa noted in the scissors group (7.2 µM, 95% CI: 5.34-9.06), followed by No. 11 blade (7.29 µM, 95% CI: 5.22-9.35), and razor blade (11.03 µM, 95% CI: 9.43-12.62). Median Ra (surface profile roughness) was 4.58 (IQR: 2.62-5.46). A Kruskal-Wallis test demonstrated statistical difference in Ra among techniques (P = 0.003), with the lowest by No. 11 blade (3 µM, IQR: 1.87-4.38), followed by scissors (3.29 µM, IQR: 1.56-4.96), and razor (5.41 µM, IQR: 4.95-6.21).

This novel technique of 3-dimensional surface analysis found razor blade use demonstrated poor roughness, whereas a No. 11 blade or nerve-specific scissors led to equivocally smooth nerve ends.