Relationship of the Exiting Nerve Root and Superior Articular Process in Kambin's Triangle: Assessment of Lumbar Anatomy Using Cadavers and Computed Tomography Imaging

Percutaneous transforaminal endoscopic diskectomy has been a major treatment for lumbar disk herniation. However, damage to exiting nerve roots is one of the most severe complications in this surgery. In this paper, the relationship of the exiting nerve root and the superior articular process in Kambin's triangle of the lumbar intervertebral foramen was assessed using cadavers and computed tomography (CT) imaging.The anatomic relationship between the exiting nerve root and the superior articular process in Kambin's triangle of the intervertebral foramen was investigated on 6 cadavers. The distance between the exiting nerve and the superior articular process of the L1-2 to L5-S1 intervertebral foramina was measured using multiplane reconstruction.The bone-nerve space between the exiting nerve root and the superior articular process in Kambin's triangle was quite narrow both in cadaver and CT imaging study. The distance of the L5-S1 intervertebral foramen was the greatest, which was no more than 5.77 ± 0.56 mm. The distances increased gradually from the tip to the root, and the distances between the root and the tip were 0.91 ± 0.31 to 1.86 ± 0.57 mm, which took on a trapezoid shape that was relatively narrow at the proximal end and wider at the distal end.The bone-nerve space between the exiting nerve root and the superior articular process in Kambin's triangle of the lumbar intervertebral foramen was exceedingly narrow. It is necessary to perform a foraminoplasty to enlarge the working space and decrease the possibility of injury to the exiting nerve root.