Iatrogenic Spinal Subdural Extra-Arachnoid Hygroma Following Uncomplicated Lumbar Decompression

Spontaneous epidural and subdural hematomas of the spine: Review of anatomy and imaging findings

Spontaneous epidural (SEH) and subdural hematomas (SSH) of the spine are a rare cause of spinal injury and morbidity. They often present in the emergency setting, though magnetic resonance imaging is the gold-standard for diagnosis. Knowledge of anatomy, and in particular of the dural layers of the spine, is crucial to understand the location of SEH and SSH and their relationship with spinal structure. In this pictorial review, we aim to explain imaging features of the SEH and SSH, and to rule out their main differential diagnosis.

Subdural hygroma as a rare complication after revision spine surgery

Spinal fusion surgery is the most commonly performed orthopaedic surgical procedure. However, subdural hygroma occurrence is a very rare complication after revision spinal fusion surgery. Here, we report a case of revision lumbar fusion surgery at the L3-4 level. The patient developed acute conus medullaris syndrome at 10 days postoperatively. MRI showed a subdural, extra-arachnoid area fluid collection following the T12-L2, cephalad to the area of revision spinal fusion. When patients have a decreased motor grade, difficulty in voiding urine and neurological abnormalities after lumbar spine surgery, conus medullaris syndrome with a possible occurrence of subdural hygroma should be considered. In this situation, immediate imaging investigations and emergency surgery might be necessary to reduce the pressure on the spinal cord.

A Case of Dural Herniation of the Cauda Equina Caused by Enlarged Spinal Subdural Extra-arachnoid Hygroma Following Lumbar Microsurgical Decompression: Case Report

We experienced a rare case of transdural herniation of cauda equina caused by increased pressure with spinal subdural extra-arachnoid hygroma (SSEH) following lumbar microsurgical decompression. A 68-year-old woman presented with complaints of right leg pain and intermittent claudication. By the diagnosis of L2/3 lumbar spinal stenosis, microsurgical decompression was performed. The surgery was successful with no issues arising such as damage to the dura mater. Lumbar magnetic resonance imaging (MRI) performed 8 days after the surgery confirmed asymptomatic SSEH on the ventral side of the cauda equina. However, posterior cervical pain and lower back pain developed 32 days after the surgery. Lumbar MRI demonstrated that SSEH had markedly increased and advanced from the lumbar spine to the cranium, compressing the spinal cord posteriorly. In addition, herniation of the cauda equina was confirmed in the dura. An emergency surgery was performed. The herniated cauda equina was fully positioned in the dural sac, and the arachnoid membrane with accumulation of spinal fluid on the ventral side was fenestrated. Immediately after the surgery, the patient’s symptoms disappeared. Sufficient caution is required regarding the possibility of SSEH associated with spinal failed back surgery syndrome as it can become excessively enlarged, leading to a poor prognosis.

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.