Unilateral spinal motion segment rotational deformity causing foraminal stenosis

The objective of this article is to describe for the first time a case of unilateral spinal motion segment rotational deformity causing foraminal stenosis. In this report we present the case of a 43 year old male with multilevel lumbar degeneration who progressively developed an isolated L3/4 rotational deformity leading to symptomatic neural compression from foraminal stenosis. He first presented to our clinic in 2015 and was followed up over the course of four years. The patient failed non-operative treatment and developed increasing L3 radiculopathy and neurological dysfunction for which he had temporary improvement of symptoms after a foraminal epidural steroid injection. He therefore underwent a decompression with no resolution of symptoms and subsequently a lateral interbody fusion that restored foraminal height but not antero-posterior (AP) compression. Subsequent derotation with pedicle screws resulted in an increase in the antero-posterior size and resolution of his symptoms. Unilateral mono-segmental rotational deformity is a cause of foraminal stenosis that should be considered when patients present with radiculopathy. Surgical management should involve restoration of the antero-posterior dimension, which can be achieved with derotation.