Reinnervation of Free Nipple Grafts Associated With Improved Erection Function

Abstract

Background: Most patients undergoing breast surgery with free nipple grafts lose nipple erection (NE) function. This study aimed to evaluate the effect of nerve preservation and reconstruction with targeted nipple-areola complex reinnervation (TNR) on NE following gender-affirming mastectomy with free nipple grafting.

Methods: Patients undergoing gender-affirming mastectomy with free nipple grafts were prospectively enrolled. Subjects who underwent TNR were compared with controls who did not undergo TNR. Postoperative patient-reported NE function was scored using a 4-point Likert scale. Objective NE evaluation consisted of the change in areola circumference and nipple height following cold application using a thermal device and 3-dimensional imaging.

Results: Twenty patients (11 subjects and 9 controls) with comparable age, body mass index, and mastectomy weight were included. At an average follow-up of 16.8 (±7.0) months, significantly more subjects reported NE than controls (72.8% versus 38.9%, P = 0.03), with a higher median NE score (3 [range 1-4] versus 1 [range 1-2], P = 0.0005). Following cold application, subjects had a greater mean reduction in areola circumference (-4.16 ± 3.3 versus -1.67 ± 1.9 mm, P = 0.02) and a greater mean increase in nipple height (+0.86 ± 0.8 versus +0.37±0.3 mm, P = 0.04) compared with controls. Improved patient-reported NE function correlated with better cold detection thresholds (P = 0.01).

Conclusions: TNR was associated with improved patient-reported and objective NE following gender-affirming mastectomy. Improved NE correlated with improved cold detection, suggesting the role of both sensory and autonomic innervation in mediating NE.

Fig. 1.

The NAC and its sensory and autonomic innervation. Sensory innervation is governed by large, myelinated fibers (type Aβ) for mechanoception, as well as small, thinly myelinated or unmyelinated fibers (type Aδ and type C) for temperature and nociception. Autonomic functions are governed by unmyelinated sympathetic nerve fibers that innervate smooth muscle cells and glands.

Fig. 2.

TNR during double incision gender-affirming mastectomy with free nipple grafting. Branches of the third through fifth lateral intercostal nerves are preserved to their distal length. If the nerves cannot directly reach the NAC, a nerve allograft or autograft is used. The distal nerve ends are passed through the superior skin flap into the deepithelialized area of the new NAC. The nerve fascicles are split, fanned out, and sutured over the dermis of the new NAC. The free nipple graft is then placed over the new NAC and nerve fascicles.

Fig. 3.

Patient-reported NE function was scored using a 4-point Likert scale (1= none, 2 = a little, 3 = quite a bit, 4 = a lot). Significantly more subjects who underwent TNR reported any NE function as compared with control patients who did not undergo TNR (72.8% vs 38.9%, P < 0.01).

Fig. 4.

This is a case of a 21-year-old trans male patient 22 months status post double incision gender-affirming mastectomy with free nipple grafting. The patient reported “quite a bit” (score 3 of 4) of NE function. Following cold application to the right free nipple graft, the areola circumference reduced from 81.76 to 74.07 mm (−7.69 mm), as shown in (A) and (B), whereas the nipple height increased from 2.46 to 5.32 mm (+2.86 mm), as shown in (C) and (D).

Fig. 5.

Improved patient-reported NE function was significantly correlated with improved mean cold detection threshold (P = 0.01). Patient-reported NE was scored using a 4-point Likert scale (1= none, 2 = a little, 3 = quite a bit, 4 = a lot).