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Spinal Arachnoid Web - a distinct entity of focal arachnopathy with favorable long-term outcome after surgical resection. Analysis of a multicenter patient population

Stefanos Voglis, Alexander Romagna, Menno R Germans, Isaac Carreno, Martin N. Stienen, Anna Henzi Md, Katrin Frauenknecht, Elisabeth Rushing, Granit Molliqaj, Kayee Tung, Enrico Tessitore, Howard J Ginsberg & David Bellut

abstract

BACKGROUND CONTEXT
Spinal arachnoid web (SAW) is a rare condition characterized by focal thickening of the arachnoid membrane causing displacement and compression of the spinal cord with progressive symptoms and neurological deficits. Recent reports and clinical experience suggest that SAW is a distinct entity with specific radiological findings and treatment strategies distinguishable from other arachnopathies and potential differential diagnoses.

PURPOSE
To better define the diagnostic and clinical features, treatment options and outcomes of surgically treated SAW.

STUDY DESIGN
Multicentric retrospective cohort study.

PATIENT SAMPLE
Twelve cases of SAW surgically treated at three different centers.

OUTCOME MEASURES
Self-reported and neurological outcome measurements (pain, sensory-motor deficits, vegetative dysfunctions) were assessed at follow-up timepoints.

METHODS
Retrospective review of prospectively collected data on all patients surgically treated for SAW from three participating neurosurgical centers between 2014 and 2020. Clinicopathological data, including neurological presentation, radiological and histological findings and outcome data were analyzed.

RESULTS
Twelve radiologically and surgically confirmed cases of SAW were analyzed. Mean patient age was 54.7 [±12.7], 67% were male. All SAWs were located in the posterior thoracic dural sac. On magnetic resonance imaging (MRI), the "scalpel sign" - a characteristic focal dorsal indentation of the spinal cord resembling a scalpel blade - was identified in all patients. A focal intramedullary syrinx was present in 83%. Preoperative clinical symptoms included signs of myelopathy, pain, weakness and sensory loss, most commonly affecting the trunk/upper back or lower extremities. Laminectomy or laminoplasty with intradural excision of the SAW was the surgical treatment of choice in all cases. Intraoperative ultrasound was valuable to visualize the cerebrospinal fluid (CSF) flow obstruction, confirm the SAW location before dura incision and to control adequacy of resection. After surgery, sensory loss and weakness in particular showed significant improvement.

CONCLUSIONS
The present study comprises the largest series of surgically treated SAW, underscoring the unique clinical, radiographic, histopathological and surgical findings. We want to emphasize SAW being a distinct entity of spinal arachnopathy with a favorable long-term outcome if diagnosed correctly and treated surgically. Intraoperative ultrasound aids visualizing the SAW before dural incision, as well as verifying restored CSF flow after resection.
   
citation Voglis S, Romagna A, Germans M R, Carreno I, Stienen M N, Md A H, Frauenknecht K, Rushing E, Molliqaj G, Tung K, Tessitore E, Ginsberg H J, Bellut D. Spinal Arachnoid Web - a distinct entity of focal arachnopathy with favorable long-term outcome after surgical resection. Analysis of a multicenter patient population. Spine J 2021;.
   
type journal paper/review (English)
date of publishing 24-06-2021
journal title Spine J
ISSN electronic 1878-1632
PubMed 34175468
DOI 10.1016/j.spinee.2021.06.018