Diagnosis and Treatment Strategies for Arachnoiditis Ossificans Following Subarachnoid Hemorrhage: A Case Report

Abstract

Arachnoiditis ossificans (AO) is a rare disease, wherein ossified lesions in the subarachnoid space ob- struct the flow of spinal fluid or compress the spinal cord, thereby causing myelopathy. Here we de- scribe a rare case of AO and discuss the diagnosis and treatment strategies for this disease. A 66-year- old man with a history of subarachnoid hemorrhage presented with gait disturbance and dysuria for 7 months. Spinal magnetic resonance imaging and computed tomography (CT) myelography showed syr- ingomyelia at the T5-T8 level and dorsally tethered spinal cord at the T8-T10 level. Preoperative non- contrast CT was not performed. The patient was diagnosed with adhesive arachnoiditis and under- went arachnoidolysis. However, intraoperative findings showed the presence of ossification lesions on the dorsal surface of the spinal cord, and intraoperative ultrasound (IOU) showed a hyperintense le- sion with acoustic shadowing on the dorsal surface of the spinal cord, with limited visibility of the spinal cord. After removal of the lesions, IOU showed untethered and well-decompressed spinal cord and restoration of cerebrospinal fluid pulsation. Based on these findings, the patient was finally diag- nosed with AO, which is an extremely rare disease, with an unknown frequency of occurrence. There- fore, all patients with adhesive spinal arachnoiditis require a preoperative noncontrast CT scan to evaluate for ossification lesions. In this case, we were fortunate to be able to treat AO with IOU, which demonstrated specific findings. Keywords: