Transitional lumbosacral segment with unilateral transverse process anomaly (Castellvi type 2A) resulting in extraforaminal impingement of the spinal nerve A pathoanatomical study of four specimens and report of two clinical cases: Commentary

摘要

The paper contains a useful, if partial, review of the literature on the far-out syndrome. But, the lumbar imaging of the two cases and the description of the surgical finding of the first case are quite confusing.Case 1: The first description of the surgical finding: "The main entrapment was outside the foramen, between the large transverse process and sacral ala" is contradicted by the following report that the main radicular encroachment was due to a "bony spur at the entrance of the foramen". The entrance into the foramen is the lower part of the lateral recess inside the spinal canal, and it does not belong to the lateral compartment. The imaging shows a severe degenerative foraminal narrowing at L5S1, which alone explains the radicular compression without a further lateral compression of the spinal nerve. I have a lot of difficulties in identifying an impingement of the nerve root, i.e., of the spinal nerve, between the transverse process and the ala of sacrum. The fifth lumbar nerve turns downward along the ventral face of the sacrum lateral to the foramen. Therefore, a far lateral pathology of the lateral process cannot cause any encroachment of the spinal nerve.