Atypical anatomy associated with a lumbar far lateral disc herniation

Abstract

Far lateral disc herniation is an uncommon but potentially significant cause of intractable leg pain associated with compression of the exiting nerve root and associated dorsal root ganglion. Since far lateral disc herniations are located outside the spinal canal, several minimally invasive paraspinal muscle-splitting techniques have been developed that allow for neural decompression with reduced soft tissue and bony trauma compared with conventional midline approaches. However, minimally invasive approaches require familiarity with the microsurgical anatomy of the extra-foraminal compartment because of the limited exposure. We report a case of an atypical anatomic relationship identified during far lateral discectomy involving a disc fragment located in a superolateral location relative to the exiting nerve root rather than the more common inferomedial location. This report highlights that familiarity with atypical locations of an extra-foraminal disc herniation and careful exploration of all quadrants in the surgical field is important during minimally invasive far lateral discectomy.