A Comprehensive Review of Surgical Interventions for Arachnoid Web Fenestation

Introduction: Arachnoid webs are rarely described pathologies consisting of thickened arachnoid tissue within the spinal cord that can eventually become painful and produce myelopathic symptoms. This pathology can be mistaken for a vascular or neoplastic lesion and has been only minimally described in previous case reports and small retrospective series. We aimed to characterize all current literature regarding surgical approaches to treatment of arachnoid webs.

Methods: A systematic search was performed utilizing the PubMed, Embase and Cochrane Library databases for all patients undergoing surgical fenestration treatment for an arachnoid web of the spinal cord. Articles were excluded if they did not describe individual patient outcomes.

Results: A total of 20 studies characterizing 41 unique individual patients were identified. The average follow up was 13.76 months (range: 0.00-80.00). There was a wide range of ages affected with a mean age of 54.41 years (range: 29.00-81.00). All arachnoid webs were localized to the thoracic and cervical spinal cord (85% and 15%, respectively). Most were characterized by the presence of syrinx on MRI imaging (78%). The lower extremity was most affected (73%) with most patients having both motor and dorsal column symptoms. All patients experienced gradually progressive symptoms until the date of surgery. A total of 98% of patients underwent open laminectomy for arachnoid cyst fenestration with an overall improvement rate of 73%. Five studies included the use of intraoperative ultrasound and zero studies utilized endoscopic, minimally invasive approaches.

Conclusion : Arachnoid webs are rare causes of myelopathy that appear to be well treated with open laminectomy, durotomy, and microsurgical fenestration of the entangled arachnoid sheath. Endoscopy could potentially be utilized as a tool for performing more precise, complete fenestration and optimizing patient outcomes with reduced surgical morbidity. However, endoscopic fenestration approaches merit further investigation until evidence proving their efficacy accrues.