Dorsal arachnoid web and scalpel sign: a diagnostic imaging entity

Ruschel, Leonardo Gilmone; Agnoletto, Guilherme José; Aurich, Lucas Alves; Vosgerau, Ronaldo

doi:10.5137/1019-5149.jtn.18394-16.1

Cited by 11 publications

(12 citation statements)

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“…6) Thus, most of preoperative diagnoses of DAW were made based on the scalpel sign with or without syringomyelia on MRI and/or CT myelograms. 2,[7][8][9][10][11][12][13] In contrast, the identification of an extra-medullary transverse band of arachnoid tissue connecting between the ventral surface of the arachnoid membrane and the dorsal surface of the spinal cord is pathognomonic for DAW, but is impossible on preoperative MRI and CT myelograms in most of the cases, possibly because DAW is a continuously fluttering thin membrane. 3) As far as we know, the arachnoid band indicating DAW was identified on preoperative images only in two cases.…”

Section: Discussionmentioning

confidence: 99%

“…In the literature, the location of DAW was described in 37 cases. [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21] In all the cases, the location of the lesion was in a thoracic segment: T1 in two cases, 16,17) T1/2 in one case, 5) T2 in one case, 14) T3 in six cases, 2,4,6,7,10) T3/4 in two cases, 6,17) T4 in six cases, 2,3,6,12,15) T4/5 in one case, 19) T5 in three cases, 2,5,19) T5/6 in one case, 20) T6 in four cases, 2,16,18) T7 in five cases, 2,6,13,21) T7/8 in two cases, 9,11) T8 in...…”

Section: Discussionmentioning

confidence: 99%

“…7,15) It is notable that most of the patients with DAW had neurological improvement immediately after the operation and before discharge, even if preoperative symptoms lasted for 1 year or longer. 19) The treatment for 37 cases described above was laminectomy with excision of DAW in 30 cases, 2,[4][5][6][7][8][9][10][11][12]14,15,[17][18][19][20][21] laminectomy with shunt placement in 4 cases, 3,16) and unknown in 3 cases: 6,13) 35 cases showed improvement in a neurological status following surgery, [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21] while only 2 cases had no improvement. 16,17) The information of follow-ups was provided in 24 of 37 cases, and the average duration was 12.8 months.…”

Section: Discussionmentioning

confidence: 99%

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A Dorsal Arachnoid Web of the Cervical Spine: A Case Report

Yamamoto

Fujimoto

Aoki

et al. 2021

NMC Case Report Journal

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Dorsal arachnoid web (DAW) is a rare entity, which has been reported only in the thoracic spine. The authors report the first case of DAW developing in the cervical spine. A 78-year-old man with several-year progressive gait disturbance and bilateral lower-extremity numbness was referred to our hospital on the suspicion of a non-enhancing cystic cervical spinal tumor. Magnetic resonance imaging (MRI) showed a focal indentation along the dorsal surface of the spinal cord at C7 associated with widened cerebrospinal fluid (CSF) space and increased T2-weighted signals in the cord at C5-C7. DAW was suspected, but because of the atypical location for DAW, computed tomography (CT) myelogram was performed and demonstrated an incomplete blockage of the CSF flow at C7 with neither visible abnormal membranes nor a cyst formation. Intraoperative ultrasonography and operative findings revealed that two fluttering membranes disturbed the CSF flow. The pathology of the excised membranes was arachnoid tissues. DAW should be suspected based on the characteristic MRI findings even if the location is in the lower cervical spine. This case seems to support the theory that DAW may be an incomplete or disrupted formation of an arachnoid cyst.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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A Dorsal Arachnoid Web of the Cervical Spine: A Case Report

Yamamoto

Fujimoto

Aoki

et al. 2021

NMC Case Report Journal

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“…Most arachnoid webs are associated with syringomyelia, the precise mechanism of which is uncertain. 2 , 19 Several theories have been discussed including forceful CSF flow resulting in arachnoid herniation into congenital, post-traumatic, post-infectious and post-operative dural defect. 3 Heiss et al.…”

Section: Discussionmentioning

confidence: 99%

Multi-modality imaging evaluation of the dorsal arachnoid web

et al. 2020

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Purpose Dorsal arachnoid web (DAW) is a rare intradural abnormality which is associated with progressive myelopathy. Our objective was to review multi-modality imaging techniques demonstrating the scalpel sign appearance in evaluation of DAW. Methods We retrospectively reviewed various imaging modalities of patients found to have DAW at our institution during January 2015 to February 2020. Five patients underwent surgical decompression with pathological correlation. The remaining patients were presumptively diagnosed based on the characteristic finding of scalpel sign. Clinical data were evaluated and correlated to imaging findings. All imaging modalities demonstrated the characteristic scalpel sign. Results Sixteen patients (10 females, and six males) with multi-imaging modalities were evaluated. Their mean age was 52 year (range 23–74 years). Fifteen patients underwent conventional spine MRI. Further high-resolution MR imaging techniques, e.g. 3D T2 myelographic sequence, were utilized with two patients. MRI spine CSF flow study was performed to evaluate the flow dynamic across the arachnoid web in one patient. Eight patients were evaluated with CT myelogram. Syrinx formation was discovered in seven (44%) patients; five (71%) of them underwent surgical resection and decompression. Two patients underwent successful catheter-directed fenestration of the web with clinical improvement. We found a statically significant positive correlation between the degree of cord displacement and compression with syrinx formation (r = 0.55 and 0.65 with p-value of 0.03 and 0.009, respectively). Conclusion DAW has characteristic scalpel sign independent of imaging modality. Multi-modality imaging evaluation of DAW is helpful for evaluation and surgical planning.

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“…Most of those uncommon and probably underreported lesions occur in the upper thoracic region. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] The lower cervical and upper thoracic posterior subarachnoid space contains numerous arachnoid strands and fibrils 21 that coalesce to form a partition (the posterior septum or septum posticum) and haphazardly arranged arachnoid trabeculae that have been dubbed "rogue strands" (Fig. 5).…”

Section: Observationsmentioning

confidence: 99%

Neuroimaging findings and pathophysiology of dorsal spinal arachnoid webs: illustrative case

Pham

Ebinu²,

Karnati³

et al. 2021

Journal of Neurosurgery: Case Lessons

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BACKGROUND Spinal arachnoid webs are uncommon and difficult to diagnose, especially because causative intradural transverse bands of arachnoid tissue are radiographically occult. Left untreated, arachnoid webs may cause progressive, debilitating, and permanent neurological dysfunction. Conversely, more than 90% of patients may experience rapid neurological recovery after resection, even with a prolonged duration of presenting symptoms. Indirect imaging signs such as spinal cord indentation and compression with cerebrospinal fluid (CSF) flow alteration provide crucial diagnostic clues that are critical in guiding appropriate management of such patients. OBSERVATIONS The authors reported a patient with no significant medical history who presented with back pain, progressive lower extremity weakness, gait ataxia, and bowel and bladder incontinence. They discussed multimodality imaging for determining the presence of arachnoid webs, including magnetic resonance imaging, phase-contrast CSF flow study, computed tomography myelography, and intraoperative ultrasound. They also discussed the detailed anatomy of the spinal subarachnoid space and a plausible pathophysiological mechanism for dorsal arachnoid webs. LESSONS The authors report on a patient who underwent comprehensive imaging evaluation detailing the arachnoid web and whose subsequent anatomical localization and surgical treatment resulted in a full neurological recovery.

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Dorsal arachnoid web and scalpel sign: a diagnostic imaging entity

Cited by 11 publications

References 1 publication

A Dorsal Arachnoid Web of the Cervical Spine: A Case Report

A Dorsal Arachnoid Web of the Cervical Spine: A Case Report

Multi-modality imaging evaluation of the dorsal arachnoid web

Neuroimaging findings and pathophysiology of dorsal spinal arachnoid webs: illustrative case

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