Disclosures: Carley R. Trentman, MD: No financial relationships or conflicts of interest

Case Diagnosis: This is a rare occurrence of a spinal arachnoid web (an abnormal formation of an arachnoid membrane in the subarachnoid space) that was diagnosed during acute rehabilitation.

Case Description: A 38-year-old male with HIV and AIDS and HHV-8 associated lymphoproliferative disease was initially admitted to the hospital with weakness, syncope, and headache with a complicated course including subarachnoid hemorrhage, status epilepticus, hydrocephalus due to VZV meningoencephalitis requiring VP shunt, saddle PE, and tracheostomy. Patient was eventually admitted to acute rehabilitation due to right hemiplegia. He progressed through his rehabilitation course for two and a half weeks until it was noticed his left lower extremity was weaker than his upper left extremity. These new findings could not be explained by his MRI Brain findings of a left medullary lesion.

Setting: Acute rehabilitation

Assessment/Results: Spinal MRI was completed and revealed a new non-enhancing T2 hyperintense spinal subdural collection between C6-C7 levels and S1 causing cord compression and displaced cauda equina nerve roots. Patient was sent to the the OR where neurosurgery performed left T1-T2 and T12 hemilaminectomies with resection of intradural arachnoid webs. Patient returned to acute rehabilitation following the surgery with some gain of strength of his left upper and lower extremities and is planned to discharge home to family.

Discussion: A spinal arachnoid web is an abnormal thickening of the bands of the intradural arachnoid tissue which can be considered a variant, a remnant, or a collapsed/disrupted arachnoid cyst. The category of a non-traumatic arachnoid web has an unknown etiology but is hypothesized to be congenital with an association of a thickened ligamentum flavum. Surgical resection is usually curative.

Conclusion: Spinal arachnoid webs are a rare pathology that require urgent operation for curative treatment. This case demonstrated the importance of clinically correlating when a patient’s deficits cannot be explained by known course and imaging.

Level of Evidence: Level V

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PM&R Meeting Abstracts - https://pmrjabstracts.org/abstract/no-spiderman-here-an-emergence-of-the-arachnoid-web/