Unintentional injection of contrast agent into the subdural space during an epidural blood patch procedure identified the site of cerebrospinal fluid leak: a case report

Background CT myelography is a definitive diagnostic tool for cerebrospinal fluid leakage. We report a case in which the site of a cerebrospinal fluid leak that had been difficult to identify on CT myelography was fortuitously localized owing to incidental injection of a contrast agent into the subdural space. Case presentation A 37-year-old man developed headache and neck pain following a massage. He was diagnosed with intracranial hypotension, but the exact site of cerebrospinal fluid leakage could not be identified by CT myelography. An epidural blood patch was performed at the Th11/12 level, during which a contrast agent was inadvertently injected into the subdural space, revealing cerebrospinal fluid leakage from the Th2/3 level into the epidural space. Conclusions An unintentional subdural injection of contrast agent resulted in extensive distribution, facilitating the precise identification of the cerebrospinal fluid leakage site.