Three-Dimensional Computed Tomographic Anatomy of the Abdominal Great Vessels Pertinent to L4-L5 Anterior Lumbar Interbody Fusion

Abstract

A recent accumulation of surgical and radiological literature has helped spine surgeons to better understand the anatomy and establish surgical trajectories to the anterior L4-L5 disc space. However, the preoperative display of anatomic data in individual subjects in the three-dimensional (3-D) mode has rarely been attempted. The objective of this study was to acquire 3-D images of the abdominal great vessels pertinent to the L4-L5 anterior lumbar interbody fusion (ALIF), and to better define the radiological vascular anatomy. The 3-D images of 100 subjects with non-spinal diseases, generated from abdominal computed tomography angiography (CTA), were analyzed retrospectively. The anatomy of the great vessels pertinent to the L4-L5 ALIF procedure was investigated by measuring the level of the abdominal aorta (AA) bifurcation and that of the inferior vena cava (IVC) confluence in relation to the lumbar vertebral body. These two complexes were segmented into upper or lower parts, or disc level. The visibility of the middle sacral artery (MSA) and the left L4 lumbar artery on the 3-D images was also assessed. The AA bifurcation level was above L4 in 4, at L4 in 55, at L4-L5 in 23, and at L5 in 18 subjects. The IVC confluence level was at L4 in 17, at L4-L5 in 14, at L5 in 68 and below L5 in 1 subject. Levels of the bifurcation of the AA/IVC as combined data showed that the AA bifurcation was usually located 1 - 2 segments above the IVC confluence. The MSA and L4 segmental artery were identified in 79 and 83 subjects, respectively. The 3-D images of the abdominal great vessels together with the lumbar spinal column were reliably depicted. Anatomic data obtained from this study are in accordance with those obtained from conventional 2-D studies, and the 3-D images can serve as a versatile tool for preoperative evaluation for the ALIF candidates and can contribute to the reduction of surgical time and perioperative vascular complications.