Anna Carrera

Male urethral injury during rectal cancer surgery is rare but significant. Scant information is available about the distances between the rectourethral space and neighboring structures. The aim of this study is to describe the anatomical relations of the male urethra. This three-pronged study included cadaveric dissection, retrospective MRI analysis, and clinical cases. Measurements included the R-Mu distance (shortest distance between the rectum and the membranous urethra), R-Am distance (distance from the anterior rectal wall to anal margin nearest to the membranous urethra), and the anal canal–rectum axis angle. The clinical study analyzed the incidence of urethral injury and associated factors among 244 consecutive men from January 2016 to January 2023. The overall incidence of urethral injury in our series was low (0.73%), but in men with tumors < 10 cm from the anal margin, it was 4% in abdominoperineal resection and 3.2% in TaTME. On preoperative MRI, the median R-Mu distance was 1 cm (IQR, range, 0.2–2.3), the median R-Am distance was 4.3 cm (range, 2–7.3), and the median anorectal angle was 128° (range, 87–160). In the cadaveric study (nine adult male pelvises), the mean R-Mu distance was 1.18 cm (range 0.8–2), and the mean R-Am distance was 2.64 cm (range 2.1–3). Avoiding urethral injury is crucial. The critical point for injury lies 2–7.3 cm from the anal margin, with a 0.2–2.3 cm distance between the rectum and the membranous urethra. Collaborating with anatomists and radiologists improves surgeons’ anatomy knowledge.

To describe the anatomical characteristics and vascularization of the biaxial hair free scrotal flap (BAES-flap) and to detail its surgical application to reconstruction of the more complex urethral strictures. We performed macro and micro anatomical dissections of the scrotum in 15 cryopreserved cadavers for the study of the arterial microvascularization of the BAES flap, and this anatomical knowledge has been implemented with the aim to improve the anterior and posterior urethra reconstructive surgical technique. For scrotal skin conditioning we performed definitive hair removal with the alexandrite laser. The BAES flap, thanks to its rich biaxial vascularization, its anatomical disposition over the urethral axis, and the suitable characteristics of hair free scrotal skin, has allowed us to perform successful one-step urethral reconstruction in complex cases such as panurethral disease, multioperated hypospadias, failed urethroplasties and obliterative stenosis. Detailed study of scrotal skin arterial vascularization is essential to design reliable and versatile genital skin flaps that result appropriate for the most complex reconstructive urethral surgery. The BAES scrotal flap complies with these requirements offering the patient a one step reconstructive option with a very satisfactory surgical experience over more than 20 years.

OBJECTIVE: To study scrotal microvascularization and apply the findings to the design of reliable skin flaps for reconstructive surgery of complex urethral or panurethral stenoses. MATERIALS AND METHODS: In 15 cryopreserved male cadavers, scrotal skin vascularization was explored using macro‐ and microdissections, and the scrotal sac made transparent using the Spalteholtz method. A meticulous descriptive analysis of the arterial network was conducted out in all cases to evaluate the number, distribution and anastomosis of the cutaneous arteries of the scrotum. RESULTS: Scrotal skin is irrigated by two main vascular systems, through the inferior external pudendal arteries and the perineal arteries, which branch into multiple scrotal arteries. These arteries are distributed in three cutaneous territories, two lateral and one central, which are widely inter‐anastomosed. Each lateral territory receives an inferior external pudendal artery which accesses at the midpoint of the scrotal root and fans out to cover the entire corresponding hemiscrotum. The central cutaneous territory is vascularized through the branches of two main scrotal arteries which are a continuation of the perineal arteries and which access via the posterior face, running deeply on both sides of the septum. CONCLUSIONS: The special anatomical distribution of scrotal branches stemming from perineal arteries enables the construction of adequate reliable longitudinal median island scrotal flaps for the reconstructive surgery of panurethral stenosis, as profuse axial vascularization is ensured.