Frequency and Characteristics of Postoperative Neuropathy in Individuals on Gender-Affirming Hormone Therapy Undergoing Gender Affirmation Surgery: A Retrospective Cohort Study.

Introduction Gender affirmation surgery includes procedures of the face, larynx, chest, reproductive system, external genitalia, and adipose tissue performed to ameliorate incongruence between gender identity and phenotype. The annual number of gender affirmation surgeries performed in the United States has increased significantly. There have been no investigations into the frequency of peripheral neuropathy after gender affirmation surgery, which is an important topic, given transgender individuals are at increased risk for delaying necessary medical care. After appreciating a number of cases of postoperative neuropathy in our clinical practice, we hypothesized that gender affirmation surgery is a high-risk procedure for postoperative neuropathy.  Methods We conducted a one-year, monocentric, retrospective cohort study utilizing clinical data of individuals on gender-affirming hormone therapy undergoing gender-affirmation surgery under general anesthesia. The study included transgender women, assigned male at birth, receiving antiandrogen, progesterone, or estrogen therapy (target range plasma estradiol concentration 90-200 pg/ml) and transgender men, assigned female at birth, receiving antiestrogen or testosterone therapy (target range plasma testosterone concentration 320-1000 ng/dl). The primary objective was to estimate the incidence of postoperative peripheral neuropathy, defined as new numbness, paresthesia, neuropathic pain, or muscle weakness occurring in a peripheral innervation territory. Secondary objectives were to summarize the clinical presentation of neuropathy and investigate for associations between procedure characteristics and neuropathy. Results We identified nine cases of postoperative peripheral nerve injury in 232 consecutive gender affirmation procedures establishing an incidence of 3.9%. All injuries were associated with surgery longer than six hours and were characterized by sensory deficits including numbness 89% (8/9) and tingling 56% (5/9), which were diagnosed by postoperative day one. Conclusions Our results suggest that gender affirmation surgery is a high-risk procedure for postoperative neuropathy, with an incidence similar to other high-risk procedures, and an incidence that is higher than the general surgical population. However, given this has not been previously reported and our study includes a heterogenous population from a single institution, our results should be considered hypothesis generating. Additional studies that include multiple institutions are needed to confirm our findings and identify modifiable risk factors for postoperative neuropathy.