Targeted Reinnervation During Gender-Affirming Mastectomy and Restoration of Sensation.

Importance: During gender-affirming mastectomy, nerves are transected, resulting in sensory loss. Nerve preservation using targeted nipple-areola complex (NAC) reinnervation (TNR) may restore sensation.

Objective: To determine the quantitative and patient-reported sensory outcomes of TNR.

Design, setting, and participants: Prospective matched cohort study of patients undergoing gender-affirming mastectomy from August 2021 to December 2022 at Weill Cornell Medicine and Massachusetts General Hospital. Data were analyzed from January to March 2023.

Exposure: Patients who underwent TNR and matched patients who did not.

Main outcomes and measures: Mechanical detection measured with monofilaments and patient-reported outcome questionnaires were completed preoperatively and at 1, 3, 6, 9, and 12 months postoperatively. Additional quantitative sensory testing was performed preoperatively and at 12 months postoperatively. The primary outcome was mechanical detection while secondary outcomes were the additional quantitative sensory testing variables and patient-reported outcomes. Exclusion criteria included peripheral nerve disorders, unmatched patients, and incomplete follow-up.

Results: A total of 25 patients who underwent TNR and 25 matched patients who did not were included. The mean (SD) age was 24.9 (5.5) years, BMI was 26.6 (5.2), and mastectomy weight was 608.9 (326.5) g; 6 patients (12.0%) were Asian, 5 patients (10.0%) were Black or African American, and 33 patients (66.0%) were White. Repeated measures analysis of variance (ANOVA) showed that the outcomes of TNR on improving mechanical detection over time was significant at the NAC (F = 35.2; P < .001) and chest (F = 4.2; P = .045). At 12 months, mean quantitative sensory values in patients who underwent TNR reached baseline and were improved compared with patients who did not undergo TNR for monofilaments (mean [SD] NAC, 3.7 [0.5] vs 4.9 [0.9]; [data]; P < .001; chest, 3.3 [0.4] vs 3.6 [0.6]; [data]; P = .002), vibration (mean [SD] NAC, 7.7 [ 0.4] vs 7.3 [0.4]; t96 = 6.3; P < .001; chest, 7.8 [0.3] vs 7.5 [0.3]; t96 = 5.1; P < .001), 2-point discrimination (NAC, 40% vs 0%; r = 20; P = .02); chest, 4.1 [1.2] cm vs 5.7 [1.8] cm; P < .001), pinprick (mean [SD] NAC, 24.9 [21.2] mN vs 82.6 [96.7] mN; t98 = 4.1; P < .001; chest, 22.5 [25.6] mN vs 54.1 [45.4] mN; t98 = 4.6; P < .001), cold (mean [SD] NAC, 23.1 [4.7] °C vs 12.0 [7.6] °C; t98 = 8.8; P < .001; chest, 23.6 [3.1] °C vs 19.7 [5.6] °C; t98 = 4.4; P < .001), warm (mean [SD] NAC, 39.9 [5.0] °C vs 45.8 [4.2] °C; t98 = 6.3; P < .001; chest, 39.4 [3.1] °C vs 42.9 [4.0] °C; t98 = 4.9; P < .001), and pressure pain detection (mean [SD] NAC, 89.9 [45.6] kPa vs 130.5 [68.9] kPa; t86 = 3.9; P < .001; chest, 128.5 [38.0] kPa vs 175.5 [49.3] kPa; t96 = 4.0; P = .001). ANOVA demonstrated that TNR significantly improved patient-reported nipple sensation (F = 60.5; P < .001), chest light touch (F = 8.1; P = .01) and erogenous sensation (F = 8.3; P = .01). Significantly more patients who underwent TNR than those who did not reported nipple hypersensitivity until 3 months postoperatively (8% vs 4% at 12 months).

Conclusion and relevance: In this prospective matched cohort study, TNR was associated with improved quantitative and patient-reported sensation. Patients should be counseled about the risk of transient NAC hypersensitivity.