Origins, Courses, and Distributions of the Lumbar Arterial Branches in Relation to the Spinal Nerves: An Anatomical Study.

Study Design: Observational, anatomical, cadaveric study.

Objective: To investigate the origins, courses, and distributions of the lumbar arterial branches in relation to the spinal nerves using Japanese cadavers.

Summary Of Background Data: Lumbar arterial branches to the spinal nerves can be damaged during posterior lumbar column osteotomy, leading to neurological complications. Spinal cord ischemia via arterial ligation has been reported to be a major cause of neurological complications in anterior thoracolumbar surgery. Although neurological deficits have been considered the most common complications in lumbar pedicle subtraction osteotomy, there is little information on the possible neurological deficits due to spinal nerve ischemia caused by damage to the lumbar arterial branches.

Methods: In total, 111 lumbar arteries (1 lumbar artery was damaged) from 14 embalmed cadavers (28 sides, L1-L4) were investigated. We examined the branching patterns and measured their diameter and length. Branches to the spinal nerves were classified as follows: radicular branch (Rb), spinal nerve branch (SNb), and plexus branch (Pxb).

Results: The Rb was identified most frequently at L1 (21.4%) and included the main branch to supply the spinal cord. The SNb diverged from the dorsal branch (59.4%) and was mainly detected at L2 (85.7%) and L3 (85.2%). The Pxb originated from the lumbar artery (56.1%) and was found most frequently at L4 (75%). The Pxb had a larger diameter and a longer length at L3 and L4 than the SNb. Both the L3 and L4 Pxbs were the main blood suppliers to the femoral nerve.

Conclusion: The L3 and L4 Pxbs mainly supplied the femoral nerve. The Pxb is likely to exist in the medial side of the spinal nerve in the extraforaminal region. Thus, the Pxb should be recognized as a very important arterial branch during operation procedures.

Level Of Evidence: 5.