Clinical Characteristics, Outcomes, and Pathology Analysis in Patients With Dorsal Arachnoid Web

Surgical Management of Thoracic Dorsal Arachnoid Webs: A 10-Year Single-Institution Experience

OBJECTIVE

Thoracic dorsal arachnoid webs are intradural membranes that may cause obstruction of cerebrospinal fluid flow and spinal cord compression. Although well recognized, they are rare and there is a paucity of long-term data on their natural history and prognosis. We reviewed radiographic features, surgical indications, and pathologic specimens of patients diagnosed with focal thoracic dorsal arachnoid webs.

METHODS

A radiology database and surgical case logs were queried for thoracic arachnoid webs at a single hospital system for a 10-year period. A retrospective chart review was performed on identified cases.

RESULTS

We identified 127 patients with dorsal thoracic arachnoid webs. Arachnoid webs were radiographically classified into 3 morphologic types: type 1 (54%) causing spinal cord deformity only, type 2 (32%) producing cord deformity with myelomalacia, and type 3 (14%) with cord deformity, myelomalacia, and syringomyelia. These arachnoid webs were commonly centered at the upper thoracic T4 segmental level. Forty-one cases (32%) required surgery, generally for thoracic myelopathy with gait instability (46%) and lower extremity numbness and pain (39%). In patients who underwent surgery, 79% experienced symptomatic improvement and 21% remained stable, after an average of 21 months follow-up evaluation. Surgical pathology revealed fibrous connective tissue (100%) with calcifications (26%) or inflammation (7%).

CONCLUSIONS

Most patients in a large series of patients with dorsal arachnoid webs did not undergo surgical intervention, but those with myelomalacia and syrinx experienced radiographic and clinical deterioration without surgery. Surgery to treat symptomatic arachnoid webs results in significant clinical improvement with low surgical morbidity.

Atypical presentation of arachnoid web causing paraparesis with absence of sensory symptoms

We present a man in his 60s with a dorsal thoracic arachnoid web spanning levels T6-T8. The patient presented with gait abnormalities, severe neuropathic lower back pain and mild urinary incontinence without sensory deficits. He underwent laminectomy with arachnoid web fenestration. At the 6-week postoperative follow-up appointment, he had increased muscle strength in his lower extremities and was able to walk without shuffling his feet, with a straight back and standing upright. This is a marked improvement from his previous hunched and shuffling gait. He has had partial resolution of his neuropathic low back pain. Arachnoid webs are often confused with other neurological disorders, most commonly idiopathic ventral cord herniation, which prolongs the time to surgical intervention. Eventual fenestration of our patient's web led to significant improvement in gait and partial relief of his neuropathic low back pain.

Spinal arachnoid web: a systematic review of a rare entity, with two illustrative case reports

Background

Spinal arachnoid web (AW) is a very rare entity, with a limited number of cases documented in the literature. Our manuscript represented a comprehensive general review, encompassing various aspects of the subject matter without focusing on any single element. The objective of this systematic review was to describe and analyze reported cases of surgically proven spinal arachnoid webs (AWs) to elucidate their imaging and clinical features, pathophysiology, and optimal management strategies, and to determine the total number of documented cases in the literature. Patterns and commonalities across reported cases were identified to provide a clearer framework for diagnosing and treating this elusive condition. A search of Web of Science, PubMed, and Scopus, respecting PRISMA guidelines, was conducted to include reported cases of surgically proven spinal AW. Our surgically proven case was included as well.

Main body of the abstract

The search yielded 196 cases of surgically confirmed spinal AWs in the literature. Adding our case, the total is 197. They are seen commonly in middle-aged patients, slightly more prevalent in males, and often without an evident cause. Sensation disturbances were the most frequently found clinical signs, followed by gait difficulties, weakness, and pain. Symptoms were predominantly located in the lower limbs and trunk. On imaging, an indentation to the rear aspect of the spinal cord was most frequently found at the mid-thorax followed by the upper thorax, often associated with a syrinx or a hyperintense T2 cord signal, usually extending rostrally. Excision was the most efficient treatment.

Short conclusion

The assessment found that AW cases are rare in the literature, indicating the disease's scarcity. It manifests insidiously, with the shortest latency reported being 2 weeks. Upper limb symptoms occur in a quarter of cases regardless of the AW's thoracic location, likely due to rostral syrinx and cerebrospinal fluid flow disturbances. Most pathology results revealed fibrous connective tissue, similar to findings in arachnoid cysts, suggesting that AW may result from a ruptured arachnoid cyst or its precursor. Using 3D SPACE STIR and CISS MRI sequences is recommended to visualize the arachnoid band directly.

Arachnoid webs with spinal cord compression: insights from three cases

Spinal arachnoid webs are intradural bands of abnormally formed arachnoid tissue, located within the subarachnoid space and causing compression of the dorsal aspect of the spinal cord. Arachnoid webs are uncommon and can be difficult to treat. We report 3 patients presenting with a spinal arachnoid web within a 6-month period. All of them exhibited signs of thoracic myelopathy and the MRI showed the pathognomonic 'scalpel sign'. Two of the patients underwent surgery for removal of their spinal arachnoid web, whereas the third patient case is currently being managed conservatively. We also present our 2D intraoperative video for arachnoid web removal and spinal cord decompression.

Spinal arachnoid webs in adults: Clinical and imaging features in a multicenter study

BACKGROUND AND PURPOSE

Spinal arachnoid webs (SAWs) are rare and can present with myelopathic symptoms. This study aims to add 85 more cases of SAWs to the literature so we can continue to analyze clinical and imaging trends of SAWs to better understand this entity and its natural history.

METHODS

An institutional review board-approved retrospective review of SAW cases between 2016 and 2022 within a metropolitan, multihospital network was performed, searching for MR and CT reports that included "arachnoid web." Of 108 identified reports, 85 patients had imaging and/or pathologically proven arachnoid webs. Demographic and clinical data were collected. Images were analyzed for SAW level, point of maximum kyphosis, presence of cord expansion, and signal intensity. The electronic medical record (EMR) was reviewed for age, sex, symptom presentation and duration, management, and outcomes.

RESULTS

Of 85 cases, the most common presenting chief complaint was back pain and weakness. All (100%) SAWs were in the dorsal thoracic subarachnoid space, with 87% (74/85) located from thoracic (T) 2 to T6. Spinal cord expansion and signal abnormality were present in 54.1% and 23.5%, respectively. Twenty-six underwent surgical resection with 20 showing improvement of at least one symptom.

CONCLUSION

We present 85 additional cases of SAWs to the existing literature. Our cases all occurred in the dorsal thoracic subarachnoid space, predominantly from T2 to T6. Patients present with symptoms like other causes of cord compression, and spinal MR studies should be evaluated routinely for the findings of SAWs. Further research could focus on understanding SAW prevalence, risk factors, and pathophysiology.