A Rapid Protocol for Intraoperative Assessment of Peripheral Nerve Myelinated Axon Count and Its Application to Cross-Facial Nerve Grafting. Issue 3 (March 2019)

• Record Type: Journal Article
• Authors: Wang, Wenjin; Kang, Sung; Coto Hernández, Iván; Jowett, Nate
• Is Part Of: Plastic and reconstructive surgery. Volume 143:Issue 3(2019:Mar.)
• Publication Date: 2019-03
• Subjects: Surgery, Plastic -- Periodicals; 617.95205
• DOI: 10.1097/PRS.0000000000005338
• Languages: English
• ISSNs: 0032-1052

Abstract

Abstract : Background: Donor nerve myelinated axon counts correlate with functional outcomes in reanimation procedures; however, there exists no reliable means for their intraoperative quantification. In this article, the authors report a novel protocol for rapid quantification of myelinated axons from frozen sections, and demonstrate its applicability to surgical practice. Methods: The impact of various fixation and FluoroMyelin Red staining strategies on resolved myelin sheath morphology from cryosections of rat and rabbit femoral and sciatic nerves was assessed. A protocol comprising fresh cryosection and rapid staining was developed, and histomorphometric results were compared against conventional osmium-postfixed, resin-embedded, toluidine blue–stained sections of rat sciatic nerve. The rapid protocol was applied for intraoperative quantification of donor nerve myelinated axon count in a cross-facial nerve grafting procedure. Results: Resolution of myelinated axon morphology suitable for counting was realized within 10 minutes of tissue harvest. Although mean myelinated axon diameter appeared larger using the rapid fresh-frozen as compared to conventional nerve processing techniques (mean ± SD; rapid, 9.25 ± 0.62 μm; conventional, 6.05 ± 0.71 μm; p < 0.001), no difference in axon counts was observed on high-power fields (rapid, 429.42 ± 49.32; conventional, 460.32 ± 69.96; p = 0.277). Whole nerve myelinated axon counts using the rapid protocol herein (8435.12 ± 1329.72) were similar to prior reports using conventional osmium processing of rat sciatic nerve. Conclusions: A rapid protocol for quantification of myelinated axon counts from peripheral nerves using widely available equipment and techniques has been described, rendering possible intraoperative assessment of donor nerve suitability for reanimation.