The Importance of Small Lateral Dural CSF Collections in Spontaneous Intracranial Hypotension: A Radiologic-Anatomic...

Spinal CSF leaks cause spontaneous intracranial hypotension (SIH), characterized by orthostatic headaches, but the detection of these leaks may require specialized and invasive spinal imaging. We have noted the presence of small lateral dural CSF collections of unclear significance on digital subtraction myelography (DSM) in some of these patients suspected of having SIH. The purpose of the present study was to compare radiographic and anatomic intraoperative findings in patients with such small lateral dural CSF collections who underwent surgical exploration.

This retrospective cohort study included a consecutive group of patients suspected of having SIH who 1) did not have a spinal longitudinal extradural collection or CSF-venous fistula on spinal imaging; 2) underwent DSM under general anesthesia in the lateral decubitus position; and 3) underwent surgery for the finding of small lateral dural CSF collections of uncertain significance.

The study group consisted of 27 patients (22 women and 5 men; mean age, 44.6 years; range, 16-72 years). DSM demonstrated a total of 31 small lateral dural CSF collections measuring 0.6-2.4 mm in diameter (mean, 1.3 mm) and 1.3-12.3 mm (mean, 3.5 mm) caudal to the origin of the neve root sleeve. Intraoperative exploration found evidence of a CSF leak in all 27 patients. One or more CSF-venous fistulas were found in 23 patients, and a pedicular type lateral CSF leak, in 4 patients. Radiographic differentiation between these 2 types of spinal CSF leaks could not be made with confidence.

Some patients suspected of having SIH have small lateral dural CSF collections on DSM caudal to the origin of the nerve root sleeve. We have found evidence of a CSF leak in all these patients on surgical exploration. This observation expands their treatment options.