Spontaneous intracranial hypotension syndrome: a novel speculative physiopathological hypothesis and a novel patch method in a series of 28 consecutive patients.

OBJECT Spontaneous intracranial hypotension (SIH) is a potentially serious pathological syndrome consisting of specific symptoms and neuroradiological signs that can sometimes be used to assess the efficacy of the treatment. In this paper the authors report a series of 28 patients with this syndrome who were all treated with an epidural blood patch at the authors' institution. The authors propose a novel physiopathological theory of SIH based on some anatomical considerations about the spinal venous drainage system. METHODS Between January 1993 and January 2007, the authors treated 28 patients in whom SIH had been diagnosed. Twenty-seven of the 28 patients presented with the typical findings of SIH on brain MR imaging (dural enhancement and thickening subdural collections, caudal displacement of cerebellar tonsils, and reduction in height of suprachiasmatic cisterns). The sites of the patients' neuroradiologically suspected CSF leakage were different, but the blood patch procedure was performed at the lumbar level in all patients. The patients were then assessed at 3-month and 1- and 3-year follow-up visits. At the last visit (although only available for 11 patients) 83.3% of patients were completely free from clinical symptoms and 8.3% complained of sporadic orthostatic headache. RESULTS The authors think that in the so-called SIH syndrome, the dural leak, even in those cases in which it can be clearly identified on neuroradiological examinations, is not the cause of the disease but the effect of the epidural hypotension maintained by the inferior cava vein outflow to the heart. The goal of their blood patch procedure (a sort of epidural block obtained using autologous blood and fibrin glue at the L1-2 level) is not to seal CSF leaks, but instead to help in reversing the CSF-blood gradient within the epidural space along the entire cord. CONCLUSIONS The authors' procedure seems to lead to good and long-lasting clinical results.