Imaging Findings in Dorsal Thoracic Arachnoid Web and the Differential Diagnosis of “Scalpel Sign”

Neurographics ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 96-102
Author(s):  
P.M. Brasil ◽  
L.P. Pereira ◽  
D.G.F. Távora ◽  
A.C.F. Camara ◽  
C.L. Macedo Filho ◽  
...  

A dorsal thoracic arachnoid web represents an intradural extramedullary transverse band of arachnoid tissue that causes mass effect and dorsal cord indentation, and can or cannot be associated with spinal cord altered signal. On sagittal MR imaging, this focal dorsal indentation of the thoracic spinal cord resembles a scalpel with its blade pointing posteriorly (called a “scalpel sign”). Although very suggestive of dorsal thoracic arachnoid web, this sign is not specific and should be differentiated from other ventral cord displacement causes (eg, idiopathic spinal cord herniation and spinal arachnoid cyst). In idiopathic spinal cord herniation, cord tissue protrudes through a ventral dural defect, and the focal deformity can be seen along the ventral aspect of the cord on spinal axial MR imaging and with a characteristic “C sign” on sagittal MR imaging; in spinal arachnoid cysts, the marginated walls and the presence of smooth, wide scalloping of the cord surface can be identified. Recognition of these imaging findings, especially the scalpel sign, can help radiologists and clinicians make a correct diagnosis of ventral cord displacement causes and allow subsequent prompt treatment for the patient.

2012 ◽  
Vol 312 (1-2) ◽  
pp. 170-172 ◽  
Author(s):  
Giorgio B. Boncoraglio ◽  
Elena Ballabio ◽  
Alessandra Erbetta ◽  
Francesco Prada ◽  
Mario Savoiardo ◽  
...  

1998 ◽  
Vol 88 (2) ◽  
pp. 331-335 ◽  
Author(s):  
Shigeru Miyake ◽  
Norihiko Tamaki ◽  
Tatsuya Nagashima ◽  
Hiromitsu Kurata ◽  
Takahiro Eguchi ◽  
...  

✓ The authors describe two occurrences of idiopathic spinal cord herniation, an entity that has been reported previously in only 11 cases. The patients described in this report presented in midlife with Brown—Séquard syndrome. Computerized tomography myelography and magnetic resonance (MR) imaging showed ventral displacement of the spinal cord with no apparent dorsal mass. Intraspinal cerebrospinal fluid (CSF) flow studies in which phase-contrast pulse sequence cine MR imaging was used displayed a normal pattern dorsal to the spinal cord. Percutaneous intrathecal endoscopic observation did not disclose dorsal intradural cysts, but ventral adhesions were seen between the spinal cord and the dura. Microsurgical intradural exploration revealed ventrolateral herniation of the cord and a ventral root through a dural defect into an epidural arachnoid cyst. The adhesions were released, the cord was repositioned intradurally, and the dural defect was patched. The patients showed gradual improvement postsurgery, as did most of the patients in the previously reported cases. The CSF flow and endoscopic studies were found to be particularly informative, and dural patching with surgical membrane is recommended.


2014 ◽  
Vol 6 ◽  
pp. JCNSD.S16180 ◽  
Author(s):  
Jon Berg-Johnsen ◽  
Eivind Ilstad ◽  
Frode Kolstad ◽  
Mark Züchner ◽  
Jarle Sundseth

Idiopathic spinal cord herniation (ISCH), where a segment of the spinal cord has herniated through a ventral defect in the dura, is a rarely encountered cause of thoracic myelopathy. The purpose of our study was to increase the clinical awareness of this condition by presenting our experience with seven consecutive cases treated in our department since 2005. All the patients developed pronounced spastic paraparesis or Brown-Séquard syndrome for several years (mean, 4.7 years) prior to diagnosis. MRI was consistent with a transdural spinal cord herniation in the mid-thoracic region in all the cases. The patients underwent surgical reduction of the herniated spinal cord and closure of the dural defect using an artificial dural patch. At follow-up, three patients experienced considerable clinical improvement, one had slight improvement, one had transient improvement, and two were unchanged. Two of the four patients with sphincter dysfunction regained sphincter control. MRI showed realignment of the spinal cord in all the patients. ISCH is probably a more common cause of thoracic myelopathy than previously recognized. The patients usually develop progressive myelopathy for several years before the correct diagnosis is made. Early diagnosis is important in order to treat the patients before the myelopathy has become advanced.


1999 ◽  
Vol 7 (5) ◽  
pp. E8 ◽  
Author(s):  
Shigeru Miyake ◽  
Norihiko Tamaki ◽  
Tatsuya Nagashima ◽  
Hiromitsu Kurata ◽  
Takahiro Eguchi ◽  
...  

The authors describe two occurrences of idiopathic spinal cord herniation, an entity that has been reported previously in only 11 cases. The patients described in this report presented in midlife with Brown-Séquard syndrome. Computerized tomography myelography and magnetic resonance (MR) imaging showed ventral displacement of the spinal cord with no apparent dorsal mass. Intraspinal cerebrospinal fluid (CSF) flow studies in which phase-contrast pulse sequence cine MR imaging was used displayed a normal pattern dorsal to the spinal cord. Percutaneous intrathecal endoscopic observation did not disclose dorsal intradural cysts, but ventral adhesions were seen between the spinal cord and the dura. Microsurgical intradural exploration revealed ventrolateral herniation of the cord and a ventral root through a dural defect into an epidural arachnoid cyst. The adhesions were released, the cord was repositioned intradurally, and the dural defect was patched. The patients showed gradual improvement postsurgery, as did most of the patients in the previously reported cases. The CSF flow and endoscopic studies were found to be particularly informative, and dural patching with surgical membrane is recommended.


2015 ◽  
Vol 23 (3) ◽  
pp. 306-308 ◽  
Author(s):  
Nardin Samuel ◽  
Christina L. Goldstein ◽  
Carlo Santaguida ◽  
Michael G. Fehlings

Spinal cord herniation is a relatively rare but increasingly recognized clinical entity, with fewer than 200 cases reported in the literature to date. The etiology of this condition remains unknown, and surgery is used as the primary treatment to correct the herniation and consequent spinal cord compromise. Some patients without clinical progression have been treated with nonoperative measures, including careful follow-up and symptomatic physical therapy. To date, however, there has been no published report on the resolution of spinal cord herniation without surgical intervention. The patient in the featured case is a 58-year-old man who presented with mild thoracic myelopathy and imaging findings consistent with idiopathic spinal cord herniation. Surprisingly, updated MRI studies, obtained to better delineate the pathology, showed spontaneous resolution of the herniation. Subsequent MRI 6 months later revealed continued resolution of the previous spinal cord herniation. This is the first report of spontaneous resolution of a spinal cord herniation in the literature. At present, the treatment of this disorder is individualized, with microsurgical correction used in patients with progressive neurological impairment. The featured case highlights the potential variability in the natural history of this condition and supports considering an initial trial of nonoperative management for patients with mild, nonprogressive neurological deficits.


Neurosurgery ◽  
2015 ◽  
Vol 77 (3) ◽  
pp. E492-E499 ◽  
Author(s):  
Eduardo Martinez-del-Campo ◽  
Karam Moon ◽  
Samuel Kalb ◽  
Hector Soriano-Baron ◽  
Nicholas Theodore

Abstract BACKGROUND AND IMPORTANCE: Thoracic spinal cord herniation (TSCH) is rare and likely underdiagnosed. It is characterized by ventral herniation of the spinal cord through a dural defect, effacement of the anterior subarachnoid space, and increased posterior subarachnoid space. We present here a case of TSCH diagnosed and surgically treated at Barrow Neurological Institute, along with supplemental intraoperative video. CLINICAL PRESENTATION: A 61-year-old man with a history of progressive myelopathy causing left lower-extremity weakness with associated numbness, impaired gait, foot drop, incontinence, and sexual impotence was referred without any previous treatment. Computed tomographic myelography and magnetic resonance imaging of the thoracic spine showed ventral spinal cord herniation at T3-T4. Neurological monitoring was recorded preoperatively and intraoperatively. The patient underwent left-sided posterolateral exploration via T3-T4 laminectomies and costotransversectomy for intradural cord release/detethering of the spinal cord with additional superior and inferior extension and repair of the dural defect. Arthrodesis was not considered necessary. After cord release, motor evoked potentials showed immediate improvement from baseline. Dural duplication was considered the cause of TSCH in this case. Total reduction of herniation was evident in postoperative images. The postoperative course was uneventful, and at the last follow-up, the patient had regained ambulation and sphincter control. CONCLUSION: Anterior displacement of the thoracic spinal cord should elicit consideration of herniation to prevent misdiagnosis and inadequate surgery. Surgical cord release and enlargement of the dural defect are safe and associated with good clinical outcomes.


2017 ◽  
Vol 26 (6) ◽  
pp. 754-759 ◽  
Author(s):  
Randall Schultz ◽  
Andrew Steven ◽  
Aaron Wessell ◽  
Nancy Fischbein ◽  
Charles A. Sansur ◽  
...  

OBJECTIVEDorsal arachnoid webs (DAWs) and spinal cord herniation (SCH) are uncommon abnormalities affecting the thoracic spinal cord that can result in syringomyelia and significant neurological morbidity if left untreated. Differentiating these 2 entities on the basis of clinical presentation and radiological findings remains challenging but is of vital importance in planning a surgical approach. The authors examined the differences between DAWs and idiopathic SCH on MRI and CT myelography to improve diagnostic confidence prior to surgery.METHODSReview of the picture archiving and communication system (PACS) database between 2005 and 2015 identified 6 patients with DAW and 5 with SCH. Clinical data including demographic information, presenting symptoms and neurological signs, and surgical reports were collected from the electronic medical records. Ten of the 11 patients underwent MRI. CT myelography was performed in 3 patients with DAW and in 1 patient with SCH. Imaging studies were analyzed by 2 board-certified neuroradiologists for the following features: 1) location of the deformity; 2) presence or absence of cord signal abnormality or syringomyelia; 3) visible arachnoid web; 4) presence of a dural defect; 5) nature of dorsal cord indentation (abrupt “scalpel sign” vs “C”-shaped); 6) focal ventral cord kink; 7) presence of the nuclear trail sign (endplate irregularity, sclerosis, and/or disc-space calcification that could suggest a migratory path of a herniated disc); and 8) visualization of a complete plane of CSF ventral to the deformity.RESULTSThe scalpel sign was positive in all patients with DAW. The dorsal indentation was C-shaped in 5 of 6 patients with SCH. The ventral subarachnoid space was preserved in all patients with DAW and interrupted in cases of SCH. In no patient was a web or a dural defect identified.CONCLUSIONSDAW and SCH can be reliably distinguished on imaging by scrutinizing the nature of the dorsal indentation and the integrity of the ventral subarachnoid space at the level of the cord deformity.


2019 ◽  
Vol 17 (4) ◽  
pp. E161-E161
Author(s):  
Siri Sahib S Khalsa ◽  
Yamaan S Saadeh ◽  
Brandon W Smith ◽  
Jacob R Joseph ◽  
Mark E Oppenlander

Abstract Spinal cord herniation is an uncommon surgically treatable cause of thoracic myelopathy and progressive paraplegia. The thoracic spinal cord focally protrudes through a defect in the dura, resulting in progressive weakness, numbness, and spasticity affecting the lower extremities, in addition to possible urinary symptoms. In this video, we present the case of a 69-yr-old female who presented with 3 yr of progressive thoracic myelopathy due to a thoracic spinal cord herniation at T4-T5. We demonstrate the surgical steps to lyse arachnoid webs, mobilize the spinal cord, reduce the spinal cord herniation, and repair the dural defect. Appropriate patient consent was obtained.


2004 ◽  
Vol 1 (2) ◽  
pp. 223-227 ◽  
Author(s):  
Ryder Gwinn ◽  
Fraser Henderson

✓ Anterior spinal cord herniation is a well-documented condition in which the thoracic cord becomes tethered within a defect in the anterior dura mater. Typical procedures have involved a posterior approach with direct manipulation of the thoracic cord to expose and blindly release its point of tethering. The authors report three cases in which a novel approach for the treatment of anterior thoracic cord herniation was performed, cord manipulation and traction are minimized, and direct dural repair of the defect is performed.


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