The anatomy of midurethral slings and dynamics of neurovascular injury

The aim of this study was to investigate the course of midurethral slings using tension-free vaginal tape. The TVT procedure was performed on six fresh pelves, measurements were obtained, and the structures were cross-referenced in 16 embalmed pelves. The midurethral sling enters the suburethral tissue 2.2–3 cm caudad to the internal urethral meatus, pierces the paraurethral musculature and vascular plexus, and exits 2±0.5 cm from the midline lateral to the point of insertion of the arcus tendineus fasciae pelvis. On the pubic tubercle the sling is 4±0.5 cm, 4±1 cm and 6±1 cm from the accessory obturator, the inferior epigastric and the external iliac vessels, respectively. The critical angle of error resulting in the external iliac vessel injury is 7–15°. A current knowledge of pelvic anatomy may help the surgeon avoid the neural and vascular structures that are in the path of the sling.