Atypical radiographic case of arachnoid web without scalpel sign

Resection of an incidentally discovered spinal arachnoid web: illustrative case

BACKGROUND

Spinal arachnoid webs (SAWs) are rare pathologies of the spinal meninges often associated with syringomyelia and the radiographic "scalpel sign." Patients can experience pain, numbness, gait disturbances, or no symptoms at all. They are typically diagnosed via magnetic resonance imaging and treated with laminectomy and excision.

OBSERVATIONS

A 61-year-old male presented after a mechanical fall and had an incidentally discovered SAW on imaging. He was initially asymptomatic and was therefore conservatively managed. Several years later, however, the patient experienced new-onset back pain, paresthesia, and balance problems, with interval imaging demonstrating worsening of the edema surrounding his SAW. The patient subsequently underwent resection of the SAW, which led to significant resolution of his symptoms.

LESSONS

An SAW can be asymptomatic or can manifest with a wide variety of symptoms. When this condition is incidentally discovered in asymptomatic patients, neurosurgeons should guide these patients to follow-up urgently if they develop any neurological symptoms. At that time, further imaging can be performed to determine if surgical treatment is indicated. Although SAW is rare, clinicians should be aware of the signs and symptoms, because prompt surgical intervention can significantly improve neurological symptoms.

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

Arachnoiditis ossificans (AO) is a rare disease, wherein ossified lesions in the subarachnoid space obstruct the flow of spinal fluid or compress the spinal cord, thereby causing myelopathy. Here we describe 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 syringomyelia at the T5-T8 level and dorsally tethered spinal cord at the T8-T10 level. Preoperative noncontrast CT was not performed. The patient was diagnosed with adhesive arachnoiditis and underwent 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 lesion 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 diagnosed with AO, which is an extremely rare disease, with an unknown frequency of occurrence. Therefore, 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.