Thoracic dorsal arachnoid web with rapid onset of symptoms: A report of two cases and brief review of the literature

Abstract

Background: Thoracic arachnoid webs are a rare entity and can be challenging to diagnose with sometimes subtle radiographic findings. Arachnoid webs can cause severe cord compression with associated syrinx and resulting myelopathy, weakness, sensory loss, and bowel/bladder dysfunction. There have been a little over 60 cases total reported in the literature with only one systematic review. The cases presented here have unique features including rapid onset of symptoms, symptomatic syrinx extending into the cervical spine, and intraoperative syrinx drainage, all of which are quite rare in the current published literature for arachnoid webs. Case Description: Here, we present two patients, a 73-year-old man and 58-year-old man presenting with different symptoms and timing of symptom progression but both with “scalpel sign” and associated syrinx present on their MRIs. Each patient underwent a laminectomy with resection of arachnoid web with complete resolution of symptoms in the first case and significant improvement in the second case. Postoperative imaging in both cases showed almost complete resolution of the syrinx. Conclusion: Early clinical evaluation and workup followed by early surgical treatment can lead to dramatic improvement in outcomes after surgery. For patients that are symptomatic from an associated syrinx, a midline myelotomy to facilitate drainage can be considered to be done concomitantly with the arachnoid web resection.

Surgical management of spinal arachnoid web in case of syringomyelia: Strategies and outcomes

“…In this patient, we sent tissue of the web for pathological analysis and learned that CD3 + T cells were found in small numbers (similar to Chang et al 6 ), which might support the hypothesis of an underlying in ammatory process resulting in consecutive brosis of connective tissue. 6,13 Another nding is small ossi cations of ligamentum avum at the level corresponding to the location of SAW, 6 which supports the hypothesis of potential infection from the epidural to the subarachnoid space. 6,14 SAW seems to be a speci c form of arachnopathy.…”

“…Nisson et al 21 pointed out that the underlying etiology of SAW remains unknown. Different authors hypothesized that SAW might be a subtype of arachnoid cyst 4,14,21,23 or an arachnoid cyst that ruptured, 13,22 while other authors assumed remnant tissue from embryologic development. 21 Nisson et al 21 concluded that a change in ow dynamics might be a growth-signal activation stimulus, which triggers a process of arachnoid thickening and growth, leading to spinal cord compression and CSF ow obstruction.…”

“…Nisson et al 21 reported in a review of 19 articles that 67% of patients with SAW had weakness, 65% numbness and/or sensory loss, and 19% incontinence. 13,21 In 81% of patients, symptoms predominated in the lower extremities, in 42% back/trunk, and 16% upper extremities. 21 On the day of surgery, half of the patients had symptoms for 1 year or longer.…”

A case of neurosurgical treatment of thoracic dorsal arachnoid web

“…About 10 days after surgery, the incision healed well, and the patient walked with 5/5 muscle strength. e [5] 2/2 73 58…”

“…[9] Outcomes of DAW Several articles report on the effectiveness of surgery for DAW patients. [2,5,9] According to Nisson et al, 91% of patients improved neurologically. [9] Hirai et al [6] showed partial improvement in five cases.…”