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Testing of Direct Neurorrhaphy Strain
Brandon S Smetana1, Jue Cao1, Gregory A Merrell1
1Indiana Hand to Shoulder Center, Indianapolis, IN.
The Journal of Hand Surgery
|October 28, 2018
Summary
9-0 nylon sutures are recommended for testing nerve repair strain, failing predictably between 5% and 8%. This offers a more reliable intraoperative measure than other tested sutures for direct nerve repair decisions.
Area of Science:
- Biomaterials Science
- Neurosurgery
- Orthopedic Surgery
Background:
- Nerve repair requires precise tensioning to ensure optimal outcomes.
- Current methods for assessing strain at nerve repair sites lack ideal reliability.
Purpose of the Study:
- To identify the optimal suture material for intraoperative strain testing at nerve repair sites.
- To determine which suture reliably fails within a 5% to 8% strain range.
Main Methods:
- Median nerves from 19 cadavers underwent transection and end-to-end repair with a single epineural suture.
- Strain was measured during tensile testing to failure.
- Eight suture types (nylon and polypropylene in various calibers) were evaluated.
Main Results:
- 9-0 nylon sutures demonstrated an average failure strain closest to 5% (4.9%).
- Sutures failing by breakage (9-0 and 10-0 nylon/polypropylene) showed more predictable results than those failing by pullout.
- 8-0 nylon and polypropylene sutures exceeded the 8% maximum strain threshold and failed by pullout.
Conclusions:
- 9-0 nylon is suggested as a more appropriate suture for testing nerve repair strain due to predictable breakage and failure within the target range.
- While 8-0 nylon and polypropylene are potential options, their failure modes (pullout) and strain levels are less ideal.
- Findings aid surgeons in deciding on direct nerve repair during operations.
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