Imaging anatomical research of lumbosacral anterior great vessels for anterior L5/S1 interbody surgery

English Keywords:Vascular anatomy  Anterior lumbar interbody fusion  Computer tomography angiography  L5/S1 intervertebral disc

English Abstract:

  【Abstract】 Objectives: To provide preoperative assessment of vascular anatomy by using 3D reconstruction computer tomography angiography(CTA) for anterior L5/S1 interbody surgery. Methods: 62 adult patients were selected, including 32 males and 30 females. The distribution of iliac vessels, anatomic parameters of interiliac triangle including distance from the included angle vertex of interiliac triangle to the inferior boundary of L5, distance between the left and right iliac vessels on the level of the inferior boundary of L5 and of the superior boundary of S1, distance between the included angle vertex of interiliac triangle and the middle of sagittal plane and the width of L5/S1 intervertebral space were measured. According to the distance between the included angle vertex of interiliac triangle and the inferior boundary of L5(＞1.2cm; 0.6-1.2cm; ＜0.6cm and ＞0; ≤0), type Ⅰ, Ⅱ, Ⅲ and Ⅳ interiliac triangle was defined respectively. The area of the interiliac triangle and the exposure percentage of lumbar L5/S1 disc were measured. Results: 54 cases(87%) had iliac vessels gap constituted by left iliac vein and right iliac artery, 4 cases(6.45%) by bilateral iliac arteries and 2 cases(3.23%) by iliac vein and 2 cases(3.23%) by left iliac artery and right iliac vein respectively. There were 42, 11, 7 and 2 cases of type Ⅰ, Ⅱ, Ⅲ and Ⅳ interiliac triangle, respectively. The differences of anatomical parameters among type Ⅰ, Ⅱ, Ⅲ were statistically significant(P<0.05). The width of L5/S1 intervertebral space was 5.3±0.6cm. The exposure area of type Ⅰ, Ⅱ, Ⅲ iliac vascular triangle was 5.00cm2(1.42-11.90cm2), 1.04cm2(0.49-2.12cm2), 0.33cm2(0.10-0.92cm2), respectively, and the exposure disc percentages was 78.3%, 59.4%, 42.5%, respectively. Conclusions: Lumbosacral computer tomography angiography can clearly display the course and distribution of lumbosacral anterior vessels, which contributes to surgical strategies of anterior L5/S1 interbody surgery.