QS4: Genital Neurosensory Outcomes After Innervated Radial Forearm Phalloplasty

PURPOSE: Radial free forearm flap (RFFF) phalloplasty is the most commonly-used technique for gender-affirming phalloplasty procedures. Microsurgical coaptation of the free flap nerves to branches of the genital nerves aims to provide patients with a sensate neophallus. Return of sensation in the neophallus is poorly understood and has yet to be well characterized in the literature. This study serves to describe sensation in the neophallus, which will assist in setting patient expectations for recovery and improving operative technique and planning, especially in selection of nerves for coaptation. METHODS: A total of 14 patients undergoing RFFF were tested for pressure sensation in the neophallus postoperatively. Testing was conducted via 1-point static (1PS) testing using the Pressure Specified Sensory Device (PSSD). A 100g monofilament was used to screen the neophallus for sensation beginning at 3 cm distal to the base and advancing distally by 1 cm until the patient reported no sensation; the PSSD was then applied at the last point the patient reported sensation for precise pressure measurements. These measurements were taken on the right and left ventral and dorsal shaft 1 cm from the ventral and dorsal midlines, respectively. The right and left urethral meatus was also measured for sensation (representing the ulnar-most skin of the RFFF). Measurements were taken at intervals beginning as early as 1 week postoperatively; the longest patient follow-up thus far has been 17 months. RESULTS: Of the 14 patients, 13 had tactile pressure sensation at their most recent measurement (range 1-17mos). The remaining patient did not have a measurement beyond one month postoperatively. Of the 14 patients, consistent long-term follow-up measurements were currently available for 7. Among these patients, return of any sensation was measured at an average of 69 days (12-160 days) postoperatively. The earliest time point at which a patient had any sensation was two weeks postoperatively while another patient had sensation through the full length of the neophallus measured at 2.5 months postoperatively; subsequent measurements of this patient showed a decreased threshold (increased sensitivity) for pressure sensation over time. CONCLUSIONS: Preliminary data suggests that innervation of the RFFF neophallus can be accomplished via microsurgical nerve coaptation and that recovery of sensation may occur much faster in some patients than previously thought possible. Further follow-up and a larger patient cohort is necessary to fully characterize nerve recovery and regeneration in gender-affirming phalloplasty patients.