Targeted NAC Reinnervation (TNR) in Gender Affirming Double Incision Mastectomy with Free Nipple Grafting
Lisa Gfrerer, MD PhD, Ashley Ehret, MD, Kathryn Packowski, Ian Valerio, MD
1Massachusetts General Hospital, Boston, MA
Background: Restoration of breast sensation has become an important goal in autologous and implant-based breast reconstruction after cancer related mastectomy. Although gender affirming mastectomy with free nipple grafting (FNG) results in similar sensory deficits, chest reinnervation concepts have not been applied to this procedure.
Methods: We describe Targeted NAC Reinnervation (TNR), a novel technique to reinnervate the FNG in patients undergoing double incision gender mastectomy with FNG. Our technique differs from previously described reinnervation techniques in several aspects: 1) the donor axon count is maximized by preserving the 3rd to 5th lateral cutaneous nerves for anastomosis to the nipple areola complex (NAC)(Fig. 1 2) the reinnervation approach varies and is based on patient anatomy (Fig.2) 3) the distal graft or donor nerve is split into fascicles to increase the reinnervation zone (Fig.3) and 3) the split fascicles are coapted to dermal sensory units (Fig. 3). Nine patients were prospectively enrolled in this study. Semmes- Weinstein filament testing (2.83, 3.61, 4.31, 4.56, 6.65) was performed mid- nipple and in the superior, inferior, medial and lateral quadrant of the NAC preoperatively, at 2 weeks, as well as at 3 months postoperatively. Subjects were asked to answer questionnaires regarding sensation at the same timepoints.
Results: Preoperatively, all patients were moderately to very concerned about nipple sensation. Average nerve allograft length was 3.5cm. The mean preoperative sensation was 3.49 mid nipple, and 3.9 in all NAC quadrants. At two weeks postoperatively, average sensation was 6.65 or insensate in all tested areas. At three months postoperatively, all patients had a positive Tinel sign. Sensation was 3.98 mid nipple, 4.16 in the superior NAC, 4.12 in the medial NAC, 3.65 at the inferior NAC and 4.17 at the lateral NAC. One patient reported return of erogenous sensation.
Conclusion: Chest reinnervation is technically feasible in patients undergoing double incision gender mastectomy with FNG. Early results show improving sensation at three months with positive Tinel sign indicating nerve regeneration across the grafted sites. Longer follow up and a control group is needed to validate these findings.
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