Far lateral disc herniation with compression of the nerve root occurs in about 10% of all symptomatic herniated discs. They can be decompressed through a paraspinal muscle splitting approach, as first described by Watkins and modified by Wiltse. “Safe corridors” have been described for transforaminal access to the lumbar spine but they don´t always correlate to the anatomy of the patient and can sometimes be confusing, as mixed terminology is used interchangeably throughout the literature.
The authors believe that a more clinically-relevant anatomical review can be useful to surgeons, especially those unexperienced with the paraspinal approach. We describe a triangle-shape structure medial to the Intertransverse Ligament (ITL), through which, access to the nerve root, accompanying vessels and disc space can be easily obtained. A step by step description of the procedure along with some pearls for the adequate visualization of said structures with this approach, particularly when using an operating microscope are presented.
We describe 9 consecutive cases of far lateral disc herniations decompressed through a paraspinal muscle splitting approach. The finding of the above-mentioned triangle was consistent in all cases. The median size of the structure was 5mm x 4 mm x 3 mm (lateral x medial x inferior). The relationship between this triangle and it´s neural and vascular structures was also consistent in all cases.