Compression of the lumbosacral trunk and S1 nerve root by calcific posterior branches of the internal iliac artery: A potential source of sciatic pain.

Abstract

The purpose of this study is to describe how lumbosacral nerve roots in the pelvis can be compressed by calcific branches of the internal iliac artery. Sciatic pain caused by nerve root compression can be painful and debilitating. Compression of nerve roots comprising the sciatic nerve can occur at their immediate exit from the spinal cord or anywhere along their length. Identifying the precise location of nerve root compression is critical for effective treatment of clinical signs and symptoms. This study of 38 cadaveric hemipelvis dissections provides evidence to support that calcific branches of the internal iliac artery may compress and deform underlying nerve roots. This deformation suggests nerve compression. Specificially, when the posterior division of the internal iliac artery or superior gluteal artery contains calcific plaque, they form a visible impression on the nerves they course over in approximately 85.7% of the time. In this study, the lumbosacral trunk is the most commonly compressed nerve root in the pelvis, but the S1 nerve root can be affected as well. When the blood vessels lacked calcific plaque, they did not produce visible deformation of the underlying nerves. Understanding this potential mechanism of nerve compression in the pelvis has clinical significance for patients with sciatic pain.