Morphometric measurements for potential dangers of anterior intra-pelvic approach in women: A cadaveric study.

Objective: This study aimed to improve the surgical anatomical knowledge of pelvic/acetabular trauma surgeons by providing detailed morphometric data on some of the most vulnerable arteries and nerves due to constant bony landmarks during anterior intra-pelvic approach fixation of acetabular fractures in women.

Methods: Ten hemipelvis were dissected from 5 female cadavers. The following measurements relative to the symphysis were performed: (1) the distance of the corona mortis anastomosis and (2) the bisection of the external iliac vein with the pubic ramus. In addition, dis- tance to the pelvic brim at the level of pectineal convexity of the following structures was measured: (3) depth of obturatory neurovascu- lar bundle, (4) superior vesical artery, and (5) vaginal artery. Also, the clock position of the (6) gluteal superior and inferior vessels due to sciatic notch in the supine position. Due to antero-superior corner of sacroiliac joint (7) location of the common iliac artery bifurcation, (8) location of the bifurcation of internal iliac vessels to truncuses, (9) bifurcation of superior gluteal artery and lateral sacral artery, and (10) L5 nerve were measured. The descriptive statistics were given as medians and ranges as this is a descriptive anatomical study without comparisons.

Results: The median distance of corona mortis to symphysis pubis was 59.5 mm (range = 58-61). The external iliac vein bisected the pubic arm 68.5 mm (range=65-70) lateral to the symphysis pubis. At the level of pectineal convexity (about the middle of the pelvic brim), obturatory neurovascular bundle, superior vesical artery, and vaginal artery were 15 mm (range=13-16), 24 mm (range=23-25), and 36 mm (range=34-38) inferior to the pelvic brim, respectively. The superior gluteal vessels leave the sciatic notch at 12 o'clock position in supine position. Inferior gluteal vessels leave the sciatic notch at 31⁄2 o'clock position (given for left side). Common iliac artery bifurcation bisects the SI joint 5 mm (4-7) superior to antero-superior corner of the Sacro-iliac (SI) joint. The internal iliac artery gives its posterior trunk 18 mm (range=15-20) straightly anterior to antero-superior corner of the SI joint. Bifurcation of superior gluteal artery and lateral sacral artery was 11 mm (range = 10-12) away from the beginning of the posterior truncus. L5 root's medial margin was 9 mm (range = 7-10) medial to this landmark, where its lateral margin was on the SI joint (2 mm medial to 2 mm lateral).

Conclusion: The majority of the bleeding complications of the major branches of the internal and external iliac arteries and neurologic palsies due to obturatory nerve and L5 nerve root damage within the operative field of the anterior intra-pelvic approach can be avoided or managed by utilizing morphometric data provided from this study.

Level of evidence: N/A.