Spinal cord compression secondary to a thoracic meningeal cyst after subarachnoid haemorrhage: a case report

Unexplained paraparesis following subarachnoid haemorrhage

Spinal arachnoid cysts (SAC) are rare in isolation and the exact aetiology is still debated. Primary (congenital) cysts are caused by structural abnormalities in the arachnoid layer and largely affect the thoracic region. Secondary cysts are induced by a multitude of factors, infection, trauma or iatrogenic response, and can affect any level of the spinal cord. While subarachnoid haemorrhage (SAH) is a relatively common condition with significant repercussions, it is extremely uncommonly associated with SAC. When present, it may develop in the months and years after the original bleed, giving rise to new neurological symptoms. Prompt treatment is needed to halt or reverse the worsening of symptoms and questions are still being asked about how best to approach this condition. A 42-year-old man presented with chronic back pain, severe worsening ataxia and numbness below the umbilicus, 7 months after treatment for a World Federation of Neurosurgical Societies grade five (WFNS V) SAH. Imaging revealed a SAC extending from T12 to L4 and causing thecal compression. This was treated with a L3 laminectomy andmarsupialisation. An improvement in neurological function was observed at 6 months. Aetiology of the SAC and its association with SAH are discussed and a review of the relevant literature is provided.

Spinal arachnoid cyst related to a nonaneurysmal perimesencephalic subarachnoid hemorrhage: case report

OBJECTIVE AND IMPORTANCE

We report the first case of a delayed symptomatic spinal arachnoid cyst related to a nonaneurysmal perimesencephalic hemorrhage. We review the literature concerning posthemorrhagic spinal arachnoid cysts.

CLINICAL PRESENTATION

A 64-year-old woman presented with progressive spinal cord compression symptoms 10 months after a nonaneurysmal perimesencephalic hemorrhage. Magnetic resonance imaging of the spine disclosed a dorsal and intradural cystic lesion producing posterior spinal cord compression.

INTERVENTION

A thoracic laminectomy allowed complete resection of the cyst. Surgical and histological findings disclosed an intradural arachnoid cyst. On postoperative follow-up, spinal magnetic resonance imaging confirmed satisfactory decompression of the spinal cord. Because of extensive arachnoiditis, the patient experienced only partial recovery from neurological deficits.

CONCLUSION

This extremely rare complication should be kept in mind when delayed lower-limb neurological deficits appear after subarachnoid hemorrhage, even in a perimesencephalic form.

Spinal cord herniation into an extradural arachnoid cyst

A herniation of the thoracic spinal cord into the mouth of an extradural arachnoid cyst is reported in a 37 year old man. This is the 20th case, but the first posterior herniation; all the others were anterior. He presented with progressive paraparesis and the magnetic resonance imaging (MRI) showed kinking of the cord into the cyst. Surgical release of the neck of the hernia was successful.