Post-op lumbar subdural hygroma: a case report.

Lumbar spinal decompression surgery is commonly performed to relieve radicular symptoms to good effect. The formation of post-operative spinal subdural hygroma, or spinal subdural extra-arachnoid hygromas (SSEH) following incidental intra-operative durotomies, have been described in previous literatures. We report a case of a 63 years old lady who had initially underwent an uneventful posterior lumbar decompression for lower limb radiculopathy, without intraoperative durotomy, with development of concurrent SSEH and spinal subarachnoid hygroma (SSSH) during the early post-operative period with cauda equina compression. Urgent surgical intervention was performed with limited durotomy to decompress the cyst through wide fenestration of the arachnoid layers and decompress the cauda equina nerve roots, with immediate recovery of her symptoms. To our knowledge, this is the first case reporting a concurrent post-operative SSEH and SSSH, without intra-operative durotomy. Both of which causing cauda equina nerve root compression which required surgical intervention. When a patient develops early post-operative recurrence of lower limb or cauda equina neurological symptoms after spinal decompression surgery, the rare entities of SSEH and/or SSSH should be considered as one of the differentials even without intraoperative durotomy as in our case. If diagnosis is suspected, surgical exploration should be performed to decompress the hygroma, as the signs and symptoms are readily reversible with prompt and early surgical treatment.