ObjectiveTo explore the suitable division of male genitalia subunits and the effectiveness of large-area perineum defect repair under its guidance.MethodsAccording to the anatomical and functional characteristics of male genitalia, the subunit division scheme was proposed: area Ⅰ, glans penis; area Ⅱ, body of penis; area Ⅲ, scrotum; area Ⅳ, scrotum. Between April 2017 and July 2019, 12 patients with large genitalia defects were treated, with an average age of 60.9 years (range, 57-66 years) and an average disease duration of 2.7 years (range, 2-5 years). The defect area involved area Ⅰ in 1 case, area Ⅱ in 7 cases, area Ⅲ in 5 cases, and area Ⅳ in 8 cases; the size of area ranged from 6 cm×4 cm to 23 cm×16 cm. The causes of defect included 3 cases of trauma, 6 cases of Paget disease, 2 cases of squamous cell carcinoma, 1 case of spindle cell tumor. According to the design of the corresponding repair scheme, the main repair methods were to rotate and advance the skin flap and pedicled skin flap in the same area. When the defect was large, the free skin flap transplantation, free skin grafting, and free mucosa transplantation were used to repair the defect.ResultsAll the patients were followed up 6-13 months with an average of 8.6 months. Skin flap, skin graft, and mucosa survived in one stage in 10 patients; infection occurred in 1 case after the scrotal flap of area Ⅲ was transferred to repair the defect in area Ⅱ, 1 case had distal venous crisis at 2 days after repair area Ⅲ defect used free anterolateral thigh flap, and after active treatment, the condition improved. The appearance of the receiving area and the supplying area was good, and the local feeling was recovered satisfactorily. The range of motion of hip joint was good in 10 cases, and 2 cases were slightly stretched but did not affect normal life. All patients had normal urination and defecation function, and were satisfied with the treatment effectiveness.ConclusionThe subunits of male genitalia can be used to guide the repair of the defect, which can better restore the physiological appearance and function, and has positive clinical significance.