Related Experiment Video
Updated: Jan 15, 2026
Intrathecal Application of a Fluorescent Dye for the Identification of Cerebrospinal Fluid Leaks in Cochlear Malformation
Published on: February 29, 2020
Temporal Characteristics of Type 2 Lateral Spinal CSF Leaks on Digital Subtraction Myelography: Fast, Medium, or Slow
Niklas Lützen1, Horst Urbach2, Florian Volz3
1From the Department of Neuroradiology (N.L., H.U., C.Z.), Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Germany niklas.luetzen@uniklinik-freiburg.de.
Background And Purpose:
Type 2 leaks occur in up to 20% of spontaneous intracranial hypotension (SIH) due to a spinal lateral dural tear, typically accompanied by an arachnoid hernia. Their CSF-outflow dynamics are unclear, but could have implications for performing myelography for the best possible detection. This cross-sectional study analyzed temporal characteristics of type 2 leaks using digital subtraction myelography (DSM).
Materials And Methods:
Between February 2020 and April 2025, 63 consecutive patients with type 2 leaks were retrospectively identified. Patients undergoing sufficient decubitus DSM (comprising additional fluoroscopy and x-ray images) were included. We assessed the time for the contrast agent to first appear in the epidural space after reaching the level of the leak intrathecally at 1-2 frames-per-second (fps) and categorized them as fast (0-9 seconds), medium (10-90 seconds), and slow (>90 seconds) leaks. Furthermore, effects of intrathecal pressurization, arachnoid hernia size, opening pressure, and symptom duration on CSF-outflow were studied.
Results:
Forty-five patients (36 women) were included. Mean age was 39.0 years (SD ±11.4 years), mean body mass index 23.2 (SD ±3.9), and median Bern score 6 (interquartile range 5). Type 2 leaks most commonly occurred at the T10/11 level (12/45; 26.7%), ranging between T7/8-L1/2. During DSM, contrast appeared in the epidural space within 0-9 seconds in 3 of 45 (6.7%), 10-90 seconds in 24/45 (53.3%), and >90 seconds in 5 of 45 (11.1%) of cases (range: 4 to 473 seconds). If DSM (or fluoroscopy/x-ray) missed the leak, subsequent conebeam or CT myelography detected it (13/45; 28.9%); total slow leaks were 18 of 45 (40%). All patients undergoing surgery (40/45) had the leak confirmed intraoperatively. In a subgroup of patients undergoing pressurization during DSM (12/45), there were significantly more leaks detected within 90 seconds (P = .22), while arachnoid hernia size, opening pressure, and symptom duration did not affect CSF-outflow significantly.
Conclusions:
Type 2 leaks show a wide range of CSF-outflow characteristics, with most being medium and slow. For DSM, we propose using a 90-second run with intrathecal pressurization and conebeam CT standby for effective leak detection, whereas less than 1 fps (eg, 0.5 fps) seems feasible to minimize radiation. Alternatively, dynamic CT myelography can be considered, though the timing of CT scans has yet to be evaluated.
