Spinal cord herniation into a congenital extradural arachnoid cyst causing Brown-Séquard syndrome. Case report

A case of conservatively managed idiopathic spinal cord herniation presenting with low-pressure headache

Idiopathic spinal cord herniation presenting with low-pressure headache is extremely rare. We present a case of thoracic ventral spinal cord herniation in a 35-year-old lady who presented with low-pressure headaches. To our knowledge, this is only the fourth case described in the literature of spontaneous ventral cord herniation presenting in this way. The patient was managed conservatively with no manifestation of focal neurological symptoms at 12-month follow-up. The proposed aetiology of spontaneous ventral cord herniation is an initial CSF leak via a dural defect, through which the cord subsequently also enters blocking the CSF leak. We endorse a conservative approach for patients who present similarly, secondary to the above pathophysiology.

Pathogenesis, management strategies, and outcome of non-communicating extradural spinal arachnoid cyst (NEAC): a systematic review

OBJECTIVE

Non-communicating extradural spinal arachnoid cysts (NEACs) are extremely rare aetiology of symptomatic spinal cord compression. The aim of this study was to address their pathogenesis, optimum management strategy and outcome through systematic review of existing published studies.

MATERIALS AND METHOD

We have found 13 eligible publications by searching through PubMed, ScienceDirect, and Google Scholar databases, published from inception to December 2020. We have analysed the data of 21 patients extracted from those 13 publications by IBM SPSS version 23.

RESULTS

According to our analysis congenital predisposition, trauma, and previous surgery history are the aetiology of NEAC. Clinical presentation of cyst depends upon the location and extent of compression or involvement of the neurovascular structures. Paraparesis with variable degree of sensory disturbance was seen among patients. Based on neuroimaging findings, NEACs are most commonly found at dorsal and dorsolumbar region. Magnetic resonance imaging (MRI) is the diagnostic modalities of choice and CT myelography can demonstrate the communication with the subarachnoid space. Recurrence rate of cyst after surgery is very low as only one out of twenty patients showed recurrence. If dural defect is not accurately addressed, the recurrence rate increased significantly.

CONCLUSIONS

Our study has highlighted aetiology, treatment strategies, and neurological outcome of NEAC. These findings may help neurosurgeons to manage this rare surgical entity for favourable outcome.

Surgical management of idiopathic thoracal ventral spinal cord herniation: a case report

Introduction

Idiopathic spinal cord herniation is a rare entity that is characterized by the displacement of the spinal cord through a defect in the dural layer and presents with symptoms of myelopathy. Surgical management usually results in good outcomes.

Case presentation

A 58-year-old female patient presented with weakness of both legs since four months. Her neurological examination showed paraplegia in the lower extremities, and ventral herniation was detected in the T9 vertebral level. The patient underwent surgery. Left T9 hemilaminectomy was followed by the reduction in the herniated spinal cord into its physiological location and the covering the anteriorly located dural defect via circumferentially covering the dural surface of the corresponding vertebral level. Postoperatively, the patient’s neurological status improved gradually and radiological scans showed a total reduction in the herniation.

Conclusion

Despite the rarity of the pathology, spinal cord herniation should be included in the differential diagnosis of the patients presenting with myelopathy or Brown–Séquard syndrome.

Case Report: Idiopathic Spinal Cord Herniation: An Overlooked and Frequently Misdiagnosed Entity

Background

Idiopathic spinal cord herniation is an extremely rare entity that is characterized by protrusion of the spinal cord through a defect in the ventral dura. Due to the paucity of enough clinical evidence, the treatment and prognosis of idiopathic spinal cord herniation are still elusive. Herein, we reported a case of idiopathic spinal cord herniation occurring at the C7–T1 levels that was treated by surgical reduction.

Case description

A 44-year-old Chinese woman presented with a 5-year history of numbness and weakness in the bilateral lower limbs. Spinal magnetic resonance imaging demonstrated ventral displacement of the spinal cord at the C7–T1 levels, and there seemed to be a cuneiform space-occupying lesion dorsal to the spinal cord. A diagnosis of the spinal intradural extramedullary tumor was suspected. An exploratory operation was performed via a posterior midline approach. Intraoperatively, we found a defect in the ventral dura through which the spinal cord herniated to the epidural space. After the herniated parenchyma was returned, an artificial dura matter was used to repair the defect. The postoperative course was uneventful. After a 3-month follow-up, the lower-extremity weakness was significantly improved, and there was no recurrence of the spinal cord herniation.

Conclusion

Preoperative diagnosis of idiopathic spinal cord herniation is exceedingly challenging. Surgical reduction of the herniated spinal cord with the repair of the dural defect is an effective approach for the treatment of this rare disorder, and the surgical outcome is favorable.

Idiopathic herniation of the thoracic spinal cord

Since 1974, when Wortzman et al were the first to describe a case of idiopathic spinal cord herniation (ISCH), the number of reported cases has increased owing to magnetic resonance imaging (MRI) now is routinely available for patients with myelopathy and spinal surgeons are becoming more familiar with this clinical entity. This extremely rare herniation occurs exclusively in the thoracic spine, causing slowly progressive myelopathy. Diagnosis is based on ventral displacement of the spinal cord in the thoracic spine. MRI is the technique of choice to exclude a posterior arachnoid cyst, the most common mistaken diagnosis, and to recognize a spinal cord herniation when an anterior dural defect is present. A case of ISCH is reported and a Literature review of this clinical entity often mis-diagnosed has been obtained.

Novel Strategy of Ventral Dural Repair for Idiopathic Thoracic Spinal Cord Herniation: Report of Outcomes and Review of Techniques

BACKGROUND

Idiopathic ventral thoracic spinal cord herniation is a rare condition that usually presents with progressive myelopathy or Brown-Séquard syndrome. More than 100 cases have been reported with significant variance in surgical treatment strategies and likewise, significant variance in patient outcomes. Although laminectomy has often been used, to date, there is no consensus regarding the optimal surgical approach or strategy for ventral dural repair.

OBJECTIVE

To report and illustrate a novel approach to repair the ventral dural defect with more than 2 yr of clinical follow-up. The specific approach and graft used are both detailed.

METHODS

A retrospective chart review of all known cases of idiopathic spinal cord herniation at the Cleveland Clinic over the last 15 yr was performed. Postoperative outcome scores (including the Japanese Orthopedic Association score, European Myelopathy score, and Nurick) were calculated preoperatively and postoperatively.

RESULTS

A total of 5 patients were identified. Four of five patients improved clinically after surgery and 1 patient remained unchanged at last follow-up (average 23.2 mo, range 12-60 mo). There were no complications. All patients had postoperative magnetic resonance imaging demonstrating realignment of the spinal cord and no recurrence of tethering.

CONCLUSION

A unilateral dorsolateral, transpedicular approach combined with laminectomy provides excellent exposure for ventral or ventrolateral dural defects associated with idiopathic spinal cord herniation and minimizes spinal cord manipulation. A collagen matrix graft used as an onlay between the spinal cord and ventral dural defect is a safe and effective option for ventral dural repair.

Idiopathic Spinal Cord Herniation Associated With a Thoracic Disc Herniation: Case Report, Surgical Video, and Literature Review

PURPOSE

The aim of this publication is to present a case of idiopathic spinal cord herniation (ISCH) associated with a transdural disk herniation, demonstrate an operative technique used to treat this condition and provide an updated review the literature.

BACKGROUND CONTEXT

ISCH is an infrequent condition that can cause progressive myelopathy leading to severe neurological dysfunction. This condition is characterized by ventral displacement of the spinal cord across a defect in the dura, either congenital or acquired, resulting in vascular compromise and adhesion that subsequently causes injury to the spinal cord. We present the management of such a patient, in addition to a review of the literature regarding management of ISCH.

METHODS

This patient underwent surgery using the dural graft sling technique for repair of the dural defect and restoration of normal spinal cord position within the thecal sac. A review of the literature revealed a total of 171 patients supplemented by our 1 patient, which were then analyzed.

RESULTS

The majority of patients, treated with a variety of surgical techniques, experienced improvements in symptomatology. Our patient experienced significant improvement in symptomatology.

CONCLUSIONS

Although ISCH is a rare clinical condition that causes myelopathy, patients managed with surgery generally, though not universally, have a favorable neurological outcome. The associated surgical technique video demonstrates the dural sling technique for the treatment of this rare disorder.

Pathogenesis of Idiopathic Ventral Herniation of Spinal Cord: Neuropathologic Analysis

BACKGROUND

Idiopathic ventral herniation of the spinal cord is rarely seen as a cause of gradually increasing neurologic deficit. Its cause has never been clarified. It could be the result of a developmental disorder at 30- to 60-day gestational age. Neuropathologic analysis of herniated spinal cord tissue could probably support this hypothesis.

CASE DESCRIPTION

In a patient suffering from idiopathic ventral herniation of the spinal cord, a biopsy was performed in order to reduce the space-occupying effect. The biopsy was taken while intraoperative neuromonitoring was used. The patient recovered uneventfully without any additional deficit. Tissue analysis included histopathologic, immunohistochemical, and molecular examination (methylation profiling). The tissue did not appear as a normally functioning spinal cord; instead, a non-neoplastic glio-(neuronal) proliferation was found.

CONCLUSION

These findings support a developmental disorder as a cause for idiopathic ventral spinal cord herniation.

Transdural Spinal Cord Herniation: Tips and Tricks

Recognition of transdural spinal cord herniation has increased over the past decade. This condition remains little known, particularly outside the specialized fields of spinal surgery and neuroradiology, leading to a significant delay in clinical diagnosis and treatment. It should be considered among the differential diagnoses in patients with gradual-onset lower-limb weakness of presumed spinal origin. Reaching a diagnosis using magnetic resonance imaging is essential to refer patients for surgery before their myelopathy worsens. We describe our surgical experience to untether the spinal cord by wrapping a dura graft around the spinal cord. Three case reports and a review of the literature are discussed.

The Pathogenesis of Ventral Idiopathic Herniation of the Spinal Cord: A Hypothesis Based on the Review of the Literature

Idiopathic ventral herniation of the spinal cord (SC) is not often encountered in daily practice. Its clinical prevalence, however, will increase through increasing awareness and more frequent use of MRI. A clear explanation of its pathophysiology has never been formulated. It was hypothesized that the findings during surgery might indicate the real causative mechanism. An extensive literature search was performed, using Embase, PubMed, and Google Scholar. Titles and abstracts were screened by two investigators, using strict inclusion and exclusion criteria. Reference lists of the full paper versions of each included article were checked. The following data were registered for the articles included: age, gender, level of herniation, relation to intervertebral disk, duration of symptoms, findings from surgery, and outcomes. Nine cases treated at our department were added. A total of 117 articles reporting on 259 patients were included. Including our cases, 268 patients were reviewed. Females outnumbered males (160/100). The mean age was 51.3 ± 12.0 years. In 236 patients, the duration of symptoms was reported: 55.5 ± 55.6 months. In 178 patients, the intraoperative findings for the herniated part of the SC were not mentioned. In 59 patients, a tumor-like extrusion was seen, without any alteration to the SC. Deformation of the SC itself was never observed. Biopsies of these structures were without clinical consequence. Based on the intraoperative findings reported in literature and the cases presented, acquired causes, such as trauma and erosion of the dura due to a herniated disk, were not plausible. We hypothesize that a non-functioning appendix to the SC can only develop during an early embryologic phase, in which several layers separate. We propose renaming this entity as congenital transdural appendix of the SC.

Symptomatic spinal extradural arachnoid cyst with cord compression in a family: case report

A family with familial spinal extradural arachnoid cyst is presented. A 14-year-old boy had an extensive T-8 through L-2 dorsal extradural arachnoid cyst with spinal cord compression and slowly progressive myelopathy. His mother had presented 4 years earlier with acute excruciating back pain due to the combination of a lumbar extradural arachnoid cyst at L2–4 and an extruded disc at L3–4. The literature is reviewed in light of the pathogenesis, imaging, and surgical technique required for treatment.

Idiopathic spinal cord herniation of the cervical cord: unusual cause of proximal muscle weakness in upper limbs

Idiopathic spinal cord herniation (ISCH) is a recognised rare cause of progressive and potentially curable myelopathy. Around 170 cases have been described in the literature, all to be found between the T2 and T8 vertebrae. We report a case of ISCH in the cervical region. A 23-year-old man with no history of trauma presented with a 6-year history of bilateral mild resting hand tremor and left scapular pain radiating to the left arm for a duration of 8 months. Nerve conduction studies showed some denervation changes of the upper limbs and bulbar regions. MRI of the spine showed anterior midline herniation of the spinal cord at the level of C7 vertebra with an associated collection of cerebrospinal fluid in the extradural space in the cervical region. Owing to the non-progressive nature of symptoms, currently the patient is managed conservatively.

Idiopathic spinal cord herniation: an imaging diagnosis with a significant delay

BACKGROUND CONTEXT

Idiopathic spinal cord herniation (ISCH) is an underrecognized entity that is often underappreciated by the neurosurgery and neuroradiologic communities. This leads to delayed diagnosis, multiple imaging studies, other diagnostic tests, inappropriate surgeries, and repeat office visits.

PURPOSE

To evaluate common associations between ISCH and patient demographics/clinical presentation and to analyze the potential for delayed diagnosis.

PATIENT SAMPLE

Patient sample included those diagnosed with ISCH on imaging at our institution from June 20, 2005 to December 3, 2012.

OUTCOME MEASURES

These were based on the patient improvement/stability/decline based on the patients' most recent clinic/office visit when compared with initial presentation.

METHODS

A retrospective search of radiology reports was performed using Illuminate software from June 20, 2005 to December 3, 2012, using the search term "idiopathic spinal cord herniation." Clinical data were reviewed including patient's age, sex, presenting clinical symptoms, number and type of imaging studies performed as part of the workup, other diagnostic tests, pain procedures, surgeries, and time between original presentation and diagnosis of ISCH on imaging.

RESULTS

A total of 55 patients had the search term "idiopathic spinal cord herniation" included in their radiology report, of which 37 patients were found to meet the imaging and clinical diagnosis of ISCH. The median time from presentation to imaging diagnosis was 20 months in patients younger than 60 years and 5 months in those 60 years or older (p=.02). Of the 37 patients evaluated, 27 (73%) had no change in symptoms, 5 patients (14%) experienced worsening of symptoms, and 5 (14%) experienced symptom improvement from original presentation to most recent office visit. Among all patients evaluated, three underwent repair of the ventral dural defect in ISCH, resulting in clinical improvement. There was a median of nine outpatient office visits, three magnetic resonance images (MRIs), and one electromyography (EMG) per patient presenting with ISCH. The most frequent complaints were neck/upper back pain in 70%, upper/lower extremity numbness/paresthesias/weakness in 49%, hyperreflexia in 22%, and burning chest pain in 22%.

CONCLUSIONS

Prolonged time to diagnosis and subsequent treatment of ISCH protracts patient symptoms and is associated with redundant diagnostic tests and patient visits. Earlier use of MRI in younger patients (younger than 60 years) may be warranted in those with a clinical presentation suggestive of Brown-Sequard symptomatology. Increasing recognition of ISCH in imaging and surgical communities would lead to improved patient care.

Spinal cord herniation after resection of cervical spinal neurofibroma with a unique presentation

BACKGROUND CONTEXT

Spinal cord herniation (SCH) is a very rare condition. It was first reported in the lumbar spine in 1974. Thereafter, cases were reported in the thoracic and cervical spine occurring either spontaneously or after vertebral fracture, nerve root avulsion, and trauma surgery.

PURPOSE

There is only one recorded case of SCH after tumor surgery. In this article, we reported the second case.

STUDY DESIGN

We described the original surgical procedure, the clinical presentation, the operative repair, and the postoperative course.

METHODS

No funding was required for this case report.

RESULTS

The patient was a 56-years-old man, who presented with SCH 5 years after subtotal excision of a cervical neurofibroma. He presented with right upper monoparesis.

CONCLUSIONS

To our knowledge, this presentation has not been reported previously in literature.

Idiopathic spinal cord herniation: Clinical review and report of three cases

Idiopathic spinal cord herniation (ISCH) is a rare condition, of unknown pathogenesis, that primarily affects the thoracic spinal cord. It is characterized by ventral displacement of the spinal cord through a dural defect. The aim of this study was to review the literature and to present a retrospective single center experience with three cases of ISCH. The literature review analyzed a total of 78 relevant publications on ISCH, which included a total of 171 patients, supplemented with 3 patients treated at our institution. Numerous case reports have demonstrated improvement in clinical outcomes after surgery; however, follow-up is predominantly short, data are incomplete, the condition is frequently misdiagnosed, and it is difficult to predict which patients will benefit from surgery. We identified 159 cases treated with surgical management. The mean symptom duration was 54 months, and the mean follow-up 33 months. The result at follow-up was improved neurological outcome in 74%, unchanged result in 18%, and worse outcome in 8%. There were 15 cases of conservative management, with mean symptom duration 52 months and mean follow-up 33 months. The neurological outcome was unchanged in 100%. ISCH is a rare condition causing progressive thoracic myelopathy, and the natural history is unknown. There is a lack of evidence-based treatment strategies, and the majority of cases are treated with surgical management at diagnosis. Management of ISCH needs to be individualized for each patient, and clinicians should be encouraged to report new cases, standardize case reports, and ensure long-term follow-up.

Spinal extradural arachnoid cysts

OBJECTIVE: Extradural arachnoid cysts (EACs) are rare causes of spinal cord compression and cauda equina. These benign lesions appear in the literature mainly as single case reports. In this article, we present the largest series found in literature, with four new cases of spinal extradural arachnoid cysts. The characteristic imaging features, details of surgical steps and strategies to prevent postoperative kyphosis in this cystic pathology will be discussed.

Spinal cord herniation: management and outcome in a series of 12 consecutive patients and review of the literature

BACKGROUND

Spinal cord herniation is a rare entity that has been recognized and described with increasing frequency in the past few years. It is characterized by herniation of the spinal cord through an anterior dural defect. In their study of 12 cases, the authors attempt to develop management and treatment guidelines for patients suffering from this condition.

METHODS

A retrospective analysis of the medical files was carried out in a series of 12 consecutive patients treated at our Institution between 1998 and 2011 for spinal cord herniation. The clinical, radiological and surgical findings, management and outcome were reviewed.

RESULTS

The male:female ratio was 5:7, with a mean age of 47 years (range 26–71 years). All patients presented a progressively worsening symptomatology. Symptoms at presentation included progressive myelopathy, corticospinal tract sign, algoparesthesia and sphincter dysfunction. The radiological appearance was uniform. All the lesions were located between the T2 and T8 vertebrae. One patient was initially managed conservatively. All patients underwent surgical correction via a posterior approach, with reduction of the herniated spinal cord, the positioning of a muscular autograft to fill the anterior cavity and closure of the dural defect with an artificial dural patch. Six patients showed improvement of preoperative symptomatology at follow-up, while the others remained free from symptom progression.

CONCLUSIONS

The authors present one of the largest studies to date regarding patients with spinal cord herniation and emphasize that the possibility of this condition must be kept in mind when addressing all patients with progressive myelopathy.

Idiopathic thoracic spinal cord herniation: retrospective analysis supporting a mechanism of diskogenic dural injury and subsequent tamponade

BACKGROUND AND PURPOSE

tSCH in the absence of spinal trauma or surgery is a rare disorder for which numerous mechanisms have been proposed. Here, we have conducted an analysis of images in all published reports of idiopathic tSCH and identified evidence supporting a pathogenesis in which anterior dural erosion at thoracic levels generates a CSF leak that pushes adjacent spinal tissue to tamponade the dural defect, causing progressive myelopathy. Additionally, we describe a case of tSCH in which postural headache was a significant symptom before myelopathy. This finding suggests that tSCH pathogenesis may be related to spontaneous intracranial hypotension.

MATERIALS AND METHODS

Published imaging from all available prior case reports in the scientific literature was reviewed to determine whether tSCH occurred at the disk or bone level. The presence of EDF, HNP, or an osteophyte in the spinal canal was determined from review of published images. Additionally, 3 previously unreported cases from the teaching files of our department were assessed by using these criteria.

RESULTS

In greater than two-thirds (47 of 67) of identified cases with published images, tSCH occurred at a disk level. When assessment was possible, EDF, HNP, and osteophytes were present in 26.8%, 30.7%, and 26.2% of cases, respectively. Overall, 52.3% of cases with published images demonstrated evidence of these abnormalities.

CONCLUSIONS

Our analysis of published imaging indicates that tSCH occurs preferentially at spinal levels and with imaging findings consistent with dural injury that support the proposed etiology of this disorder.

The value of intraoperative motor evoked potential monitoring during surgical intervention for thoracic idiopathic spinal cord herniation

OBJECT

Thoracic idiopathic spinal cord herniation (TISCH) is a rare neurological disorder characterized by an incarceration of the spinal cord at the site of a ventral dural defect. The disorder is associated with clinical signs of progressive thoracic myelopathy. Surgery can withhold the natural clinical course, but surgical repair of the dural defect bears a significant risk of additional postoperative motor deficits, including permanent paraplegia. Intraoperative online information about the functional integrity of the spinal cord and warning signs about acute functional impairment of motor pathways could contribute to a lower risk of permanent postoperative motor deficit. Motor evoked potential (MEP) monitoring can instantly and reliably detect dysfunction of motor pathways in the spinal cord. The authors have applied MEPs during intraoperative neurophysiological monitoring (IOM) for surgical repair of TISCH and have correlated the results of IOM with its influence on the surgical procedure and with the functional postoperative outcome.

METHODS

The authors retrospectively reviewed the intraoperative neurophysiological data and clinical records of 4 patients who underwent surgical treatment for TISCH in 3 institutions where IOM, including somatosensory evoked potentials and MEPs, is routinely used for spinal cord surgery. In all 4 patients the spinal cord was reduced from a posterior approach and the dural defect was repaired using a dural graft.

RESULTS

Motor evoked potential monitoring was feasible in all patients. Significant intraoperative changes of MEPs were observed in 2 patients. The changes were detected within seconds after manipulation of the spinal cord. Monitoring of MEPs led to immediate revision of the placement of the dural graft in one case and to temporary cessation of the release of the incarcerated spinal cord in the other. Changes occurred selectively in MEPs and were reversible. In both patients, transient changes in intraoperative MEPs correlated with a reversible postoperative motor deficit. Patients without significant changes in somatosensory evoked potentials and MEPs demonstrated no additional neurological deficit postoperatively and showed improvement of motor function during follow-up.

CONCLUSIONS

Surgical repair of the dural defect is effected by release and reduction of the spinal cord and insertion of dural substitute over the dural defect. Careful monitoring of the functional integrity of spinal cord long tracts during surgical manipulation of the cord can detect surgically induced impairment. The authors' documentation of acute loss of MEPs that correlated with reversible postoperative motor deficit substantiates the necessity of IOM including continuous monitoring of MEPs for the surgical treatment of TISCH.

Idiopathic spinal cord herniation at two separate zones of the thoracic spine: the first reported case and literature review

BACKGROUND CONTEXT

Idiopathic spinal cord herniation (ISCH) is a rare cause of progressive myelopathy. Preoperative diagnosis can be made with magnetic resonance imaging (MRI). Many surgical techniques have been applied by various authors, and ISCH is usually reversible by surgical treatment.

PURPOSE

To present a case of ISCH in two separate zones at two thoracic levels. To our knowledge, this is the first such case to be published in English literature. We also discuss the clinical findings, surgical procedures, and surgical outcomes for other previously reported cases of ISCH in the literature.

STUDY DESIGN

Case report.

METHODS

A 52-year-old woman with bilateral lower extremity weakness underwent thoracic MRI, which revealed transdural spinal cord herniation at two separate zones, namely, the T4-T5 and T5-T6 intervertebral disc levels.

RESULTS

During surgery, the spinal cord was reduced, the two separate dural defects were connected, and the new single defect was restored then reinforced with a thin layer of fascial graft. The posterior dural defect was then closed with interrupted stitches. The patient's neurologic status was characterized by no changing of the preoperative motor status. Follow-up MRI scans showed that the cord was replaced in the dural sac and showed cord hyperintensity in the herniation levels. The patient could move with a cane at the sixth month postoperatively.

CONCLUSIONS

Idiopathic spinal cord herniation is a rare clinical condition that should be considered in the differential diagnosis of paraplegia. Although progression of neurologic deficits can be very slow, reduction of the spinal cord and repair of the defect are crucial to stop or reverse the deterioration. The outcome for patients who initially have Brown-Séquard syndrome is significantly better than for patients who presented with spastic paralysis. To our knowledge, this case study represents the first reported instance in which two separate anterior dural defects caused two levels of anterior spinal cord herniation.

Symptomatic isolated lumbar interdural arachnoid cyst

A 72-year-old man presented with an extremely rare case of symptomatic isolated lumbosacral interdural arachnoid cyst manifesting as pain and weakness in the right buttock and lower extremity that had aggravated for 2 weeks. Although the surgical strategy for the interdural cyst was not complicated, the origination of the cyst was not clearly understood. Surgery found an isolated membrane of the cyst inside double-layered dura without communication with the intact arachnoid membrane. Cerebrospinal fluid with hemorrhage accumulated within the interdural cyst indicated recent bleeding into the cyst. Our experience suggests that this cyst was congenital based on the surgical results and imaging studies.

Idiopathic ventral spinal cord herniation: a rare presentation of tethered cord

Idiopathic ventral spinal cord herniation is a rare condition that has been increasingly reported in the last decade. The natural history and optimal management have yet to be defined. Therefore, debate exists regarding the pathogenesis and surgical management of this condition. The purpose of this review article is to further educate neurosurgeons about the surgical techniques and outcomes associated with treating this rare and often misdiagnosed condition.

Image classification of idiopathic spinal cord herniation based on symptom severity and surgical outcome: a multicenter study

Object

The purpose of this study was to provide the first evidence for image classification of idiopathic spinal cord herniation (ISCH) in a multicenter study.

Methods

Twelve patients who underwent surgery for ISCH were identified, and preoperative symptoms, severity of paralysis and myelopathy, disease duration, plain radiographs, MR imaging and CT myelography findings, surgical procedure, intraoperative findings, data from spinal cord monitoring, and postoperative recovery were investigated in these patients. Findings on sagittal MR imaging and CT myelography were classified into 3 types: a kink type (Type K), a discontinuous type (Type D), and a protrusion type (Type P). Using axial images, the location of the hiatus was classified as either central (Type C) or lateral (Type L), and the laterality of the herniated spinal cord was classified based on correspondence (same; Type S) or noncorrespondence (opposite; Type O) with the hiatus location. A bone defect at the ISCH site and the laterality of the defect were also noted.

Results

Patients with Type P herniation had a good postoperative recovery, and those with a Type C location had significant severe preoperative lower-extremity paralysis and a significantly poor postoperative recovery. Patients with a bone defect had a significantly severe preoperative myelopathy, but showed no difference in postoperative recovery.

Conclusions

The authors' results showed that a Type C classification and a bone defect have strong relationships with severity of symptoms and surgical outcome and are important imaging and clinical features for ISCH. These findings may allow surgeons to determine the severity of preoperative symptoms and the probable surgical outcome from imaging.

Operative treatment of anterior thoracic spinal cord herniation: three new cases and an individual patient data meta-analysis of 126 case reports

OBJECTIVE

Anterior thoracic spinal cord herniation is a rare cause of progressive myelopathy. Much has been speculated about the best operative treatment. However, no evidence in favor of any of the promoted techniques is available to date. Therefore, we decided to analyze treatment procedures and treatment outcomes of anterior thoracic spinal cord herniation to identify those factors that determine postoperative outcome.

METHODS

An individual patient data meta-analysis was conducted, focusing on age, gender, vertebral segment of herniation, preoperative neurological status, operative interval, operative findings, operative techniques, intraoperative neurophysiological monitoring, postoperative imaging, neurological outcome and follow-up. Three cases from our own institution were added to the material collected. Bivariate analysis tests and multivariate logistic regression tests were used so as to define which variables were associated with outcome after surgical treatment of anterior thoracic spinal cord herniation.

RESULTS

Brown-Séquard syndrome and release of the herniated spinal cord appeared to be strong independent factors, associated with favorable postoperative outcome. Widening of the dura defect is associated with the highest prevalence of postoperative motor function improvement when compared with the application of an anterior dura patch (P < 0.036).

CONCLUSION

Most patients with anterior thoracic spinal cord herniation require operative treatment because of progressive myelopathy. Patients with Brown-Séquard syndrome have a better prognosis with respect to postoperative motor function improvement. In this review, spinal cord release and subsequent widening of the dura defect were associated with the highest prevalence of motor function improvement. D-wave recording can be a very useful tool for the surgeon during operative treatment of this disorder.

Idiopathic spinal cord herniation: case report and review of the literature

BACKGROUND

Idiopathic spinal cord herniation (ISCH) is a rare cause of progressive myelopathy frequently present in Brown-Séquard syndrome. Preoperative diagnosis can be made with magnetic resonance imaging (MRI). Many surgical techniques have been applied by various authors and are usually reversible by surgical treatment.

METHODS

Case report and review of the literature.

FINDINGS

A 45-year-old woman with Brown-Séquard syndrome underwent thoracic MRI, which revealed transdural spinal cord herniation at T8 vertebral body level. During surgery the spinal cord was reduced and the ventral dural defect was restorated primarily and reinforced with a thin layer of subdermal fat. The dural defect was then closed with interrupted stitches.

RESULTS

Although neurologic status improved postoperatively, postsurgical MRI demonstrated swelling and abnormal T2-signal intensity in the reduced spinal cord. Review of the English language literature revealed 100 ISCH cases.

CONCLUSIONS

ISCH is a rare clinical entity that should be considered in differential diagnosis of Brown-Séquard syndrome, especially among women in their fifth decade of life. Outcome for patients who initially had Brown-Séquard syndrome was significantly better than for patients who presented with spastic paralysis. Although progression of neurologic deficits can be very slow, reduction of the spinal cord and repair of the defect are crucial in stopping or reversing the deterioration.

Spontaneous herniation of the spinal cord: operative technique and follow-up in 10 cases

Object

The authors report on a series of 10 patients with spontaneous thoracic cord herniation, provide the longterm follow-up, and propose a surgical strategy.

Methods

All 10 patients had a defect in the ventral dura mater. They were all treated surgically with wide excision of the dura around the defect, repositioning of the cord, and reconstruction with a ventral patch. Five patients were followed up for > 4 years.

Results

Surgery improved motor power in 4 patients and pain in 2 patients, although sensory disturbances remained unchanged in all but 1 patient. One patient's condition deteriorated secondarily due to edema and syringomyelia.

Conclusions

Microsurgical treatment may halt the exacerbation of neurological symptoms and should be performed with progressive deficits. Long-term results are good regarding the motor function.

Spinal cord herniation into pseudomeningocele after traumatic nerve root avulsion: case report and review of the literature

We present an extremely rare case of traumatic spinal cord herniation due to a brachial plexus avulsion injury and provide a review of the literature of spinal cord herniation. Spinal cord herniation is an uncommon condition that can occur spontaneously or as a result of surgery or trauma. This condition often presents with symptoms and signs as Brown-Séquard syndrome. Traumatic pseudomeningoceles after a brachial plexus avulsion injury have been reported. But transdural herniation of the spinal cord into this pseudomeningocele is an extremely rare and poorly documented condition. There is only two reports of this condition in a thoracic case. The authors report the case of a 22-year-old man presented with a 2-year history of quadriplegia. He was involved in a motorcycle accident, 3 years prior to his presentation. Four years after the initial right brachial plexus injury, he was not able to walk independently. Magnetic resonance imaging (MRI) and computerized tomography (CT) myelography revealed a lateral pseudomeningocele arising from the right C6-7 and C7-T1 intervetebral foramen and cervical spinal cord herniation into this pseudomeningocele. The patient underwent primary closure of pseudomeningocele to prevent spinal cord reherniation. He can walk with cane and use left arm unrestrictedly at the 2-year follow-up examination. Spinal cord herniation following traumatic nerve root avulsion is extremely rare but it should be considered in the differential diagnosis of patients presenting with delayed myelopathy or Brown-Séquard syndrome.

Diagnosis and treatment of spinal cord herniation: a combined experience

OBJECT

Idiopathic spinal cord herniation (ISCH) is an uncommon clinical entity typically presenting with lower-extremity myelopathy. Despite the existence of 85 ISCH cases in the literature, misdiagnosis and delayed diagnosis remain a major concern.

METHODS

The authors conducted a retrospective review of patients who underwent surgery for ISCH at their institutions between 1993 and 2004. Seven patients were treated for ISCH, five in New York and two in Buenos Aires. The patients' ages ranged from 32 to 72 years. There were three men and four women. The interval between the onset of symptoms and surgery ranged from 12 to 84 months (mean 42.1 months). Preoperatively, spinal cord function in four patients was categorized as American Spinal Injury Association (ASIA) Grade D, and that in the other three patients was ASIA Grade C. In all patients a diagnosis of posterior intradural arachnoid cyst had been rendered at other institutions, and three had undergone surgery for the treatment of this entity. In all cases, the herniation was reduced and the defect repaired with a dural patch. The follow-up period ranged from 10 to 147 months (mean 49.2 months). Clinical recovery following surgery varied; however, there was no functional deterioration compared with baseline status. Syringomyelia, accompanied by neurological deterioration, developed post-operatively in two patients at 2 and 10 years, respectively.

CONCLUSIONS

Patients presenting with a diagnosis of posterior intradural arachnoid cyst should be evaluated carefully for the presence of an anterior spinal cord herniation. Based on the authors' literature review and their own experience, they recommend offering surgery to patients even when neurological compromise is advanced.

Surgical treatment of idiopathic transdural spinal cord herniation: a new technique to untether the spinal cord

Idiopathic transdural spinal cord herniation is a rare but treatable cause of thoracic myelopathy caused by herniation of the spinal cord through a defect in the dura. The diagnosis is frequently missed or delayed, but the latest imaging techniques can document spinal cord herniation through a dural defect. Surgical treatment, consisting of reducing the herniation by closing the dural defect or widening the aperture to prevent spinal cord compression, is rather successful. We describe a new technique to untether the spinal cord by wrapping a dura graft around the myelum to prevent recurrent transdural herniation. Two patients and a review of the literature are discussed. We conclude that high-resolution T2 magnetic resonance imaging is the best imaging modality to detect the entity, and wrapping the myelum is an effective surgical technique to untether the spinal cord.

Ventral thoracic spinal cord herniation: frequently misdiagnosed entity

STUDY DESIGN

Case report with review of the literature.

OBJECTIVE

Symptomatic spinal cord herniation through ventral aspect of dura is frequently misdiagnosed because this condition is rare. The most frequent misdiagnosis was that of dorsal arachnoid cyst. The purpose of this article is to provide insight on clinical presentation, diagnosis, and surgical treatment of this entity. Results of our cases were compared with that of the reported literature.

SUMMARY OF BACKGROUND DATA

Eighty-six cases reported in the literature were reviewed and data are presented in this article.

METHODS

We had 3 patients diagnosed with spinal cord herniation through the ventral aspect of the dural sac. All 3 cases were misdiagnosed initially and later successfully operated. The dura was repaired primarily with suture in 1 case and with surgical graft in the other 2 cases.

RESULTS

Reduction of spinal cord herniation reverses some of the signs and symptoms that have been present for years. Two of our patients had remarkable recovery in motor strength and bladder function. The third patient improved but remained with residual myelopathy.

CONCLUSION

Ventral herniation of the thoracic spinal cord is a partially treatable cause of myelopathy, when recognized promptly and treated surgically. Recognizing this infrequent cause of myelopathy prevents misdiagnosis. Delay in diagnosis may impair recovery at a later date.

Thoracic ventral dural defect: Idiopathic spinal cord herniation

Thoracic ventral dural defect, and resultant idiopathic spinal cord herniation, is a rare but increasingly recognized cause of a chronic progressive thoracic myelopathy, particularly in middle-aged women. A neurosurgically confirmed case is presented, together with a review of the pathogenesis, clinical presentation, imaging features, treatment options and progress of this entity post-treatment.

Idiopathic spinal cord herniation causing progressive Brown-Séquard syndrome

We report a 59-year-old woman with a 2.5 year history of progressive loss of temperature sensation and dysesthesia in the right and weakness in the contralateral lower limb. Magnetic resonance imaging (MRI) and computed tomography myelography of the spinal cord demonstrated transdural herniation and deformation of the spinal cord in the upper thoracic spine. The herniated part of the spinal cord was untethered and replaced, and the anterior dural defect was closed. At a clinical follow-up 3 months later, the motor and sensory functions were almost restored. MRI at this time showed disentanglement of spinal cord adherence.

Giant cervicothoracic extradural arachnoid cyst: case report

The pathogenesis, etiology, and treatment of the spinal arachnoid cyst have not been well established because of its rarity. A 57-year-old male was presented with spastic quadriparesis predominantly on the left side. His radiological examination showed widening of the cervical spinal canal and left neural foramina due to a cerebrospinal fluid - filled extradural cyst that extended from C2 to T2 level. The cyst was located left anterolaterally, compressing the spinal cord. Through a C4–T2 laminotomy, the cyst was excised totally and the dural defect was repaired. Several features of the reported case, such as cyst size, location, and clinical features make it extremely unusual. The case is discussed in light of the relevant literature.

Type I congenital multiple intraspinal extradural cysts associated with distichiasis and lymphedema syndrome

OBJECTIVE

The hereditary syndrome of multiple congenital intraspinal cysts associated with distichiasis, lymphedema and other congenital deformities is extremely rare. Modern imaging techniques have promoted the non-invasive diagnosis of spinal pathology and paved the way for better surgical planning. We reviewed the clinical data, imaging studies and treatment outcomes of a 12-year-old boy with this syndrome.

CLINICAL PRESENTATION

Progressive spastic paraparesis with signs of spinal cord compression leading to frequent falls. This was associated with bilateral double row of eyelashes and pretibial edema. The MRI of thoracic spine depicted two large elongated extradural lesions extending from D5-D10 with signal intensity compatible with cerebrospinal fluid leading to severe compression of the spinal cord dorsally.

TREATMENT

Laminotomy and complete microsurgical excision of the cysts resulted in a fast and full clinical recovery of his neurological deficit.

CONCLUSION

Type I congenital intraspinal cysts is a rare etiology of cord compression syndrome and may be associated with distichiasis, lymphedema and other congenital deformaties. It has several characteristics, which include the higher incidence in thoracic spine and younger age group, disproportional sever motor deficit as compared with sensory disturbances and the excellent clinical recovery following successful surgical treatment.

Idiopathic spinal cord herniation: diagnostic, surgical, and follow-up data obtained in five cases

✓ Idiopathic spinal cord herniation (ISCH) is a rare, although increasingly recognized, cause of myelopathy. It is the result of an anterior dural defect in the thoracic spine through which the spinal cord herniates. Surgical restoration of the herniated cord to its normal position is usually followed by significant improvement in patients' clinical status. Differing surgical techniques have been used to manage the dural defect.

In this report the authors discuss the cases of five patients (four women and one man) with ISCH treated during a 13-year period. Clinical and imaging findings in each patient are reported. Two different surgical techniques were used to treat this condition: dural defect enlargement in two cases and dural patch secured with stitches in three. The intra-and postoperative findings are discussed in relation to the two surgical techniques.

Based on the results and complications in these five cases, the authors now believe that ISCH should be treated, when feasible, by using a dural patch to close the dural defect at the site of the herniation.

Transdural spinal cord herniation: pre- and postoperative MRI findings

Idiopathic transdural spinal cord herniation (ICSH), a rare condition which may cause progressive myelopathy, can be diagnosed preoperatively by MRI. Surgical treatment usually results in the resolution of symptoms and, thus, familiarity with the imaging findings in this condition impacts patient management. We present the case of a 36-year-old woman in whom the initial MRI findings were thought to be consistent with only an arachnoid cyst compressing the spinal cord. After surgery, her symptoms remained unchanged, and a repeat MRI study was interpreted as being compatible with a transdural spinal cord herniation. Repeated surgery with reduction of the herniation resulted in significant clinical improvement.

Spontaneous Thoracic Spinal Cord Herniation: Three Cases with Long-term Follow-up

OBJECTIVE AND IMPORTANCE

Spontaneous thoracic spinal cord herniation (STSCH) is an uncommon cause of thoracic myelopathy. Fewer than 40 cases have been reported in the English language literature with a mean follow-up of less than 6 months.

CLINICAL PRESENTATION

We have encountered three patients diagnosed with STSCH in the last 6 years at our institution. These patients presented with symptoms and signs localizing to the thoracic spinal cord. Magnetic resonance imaging revealed ventral thoracic spinal cord displacement in each.

INTERVENTION

One patient was treated surgically, two managed expectantly. Two patients have been followed for greater than 5 years, whereas a third has been followed for 15 months.

CONCLUSION

Our experience suggests that patients with neurological symptoms and signs attributable to STSCH may not progress and therefore may be followed with clinical and magnetic resonance imaging surveillance. When surgery is indicated for progressive STSCH, late retethering may occur.

MR imaging features of idiopathic thoracic spinal cord herniations using combined 3D-fiesta and 2D-PC cine techniques

Idiopathic thoracic spinal cord herniation (TISCH) is a rare cause of surgically treatable progressive myelopathy. The authors report 3 cases of TISCH diagnosed based on conventional T1- and T2-weighted Spin-Echo (SE) MR images in one case, and T1- and T2-weighted SE images combined with 3D-FIESTA (Fast Imaging Employing Steady state Acquisition) and 2D-Phase-Contrast Cine MR imaging in 2 cases. Conventional MRI findings usually provided the diagnosis. 3D-FIESTA images confirmed it, showing the herniated cord in the ventral epidural space. Moreover, in combination with 2D-Phase Contrast cine technique, it was a sensitive method to for the detection of associated pre- or postoperative cerebrospinal fluid spaces abnormalities.

Transdural herniation of the thoracic spinal cord: untethering via a posterolateral transpedicular approach. Report of three cases

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.

Idiopathic spinal cord herniation: a new theory of pathogenesis

BACKGROUND

Idiopathic spinal cord herniation is a rare entity that has been described more frequently over the past few years. Its pathophysiology remains obscure, however.

METHODS

We report a case of spinal cord herniation and review the literature extensively. In view of our review, we try to determine the clinical features of the condition and the diagnostic measures used, with emphasis on the role of magnetic resonance (MR) phase-contrast CSF study. The factors affecting the outcome of the condition are also studied including time and type of presentation, as well as the surgical procedure performed. The pathophysiological mechanisms behind spontaneous herniation are discussed, and a new hypothesis is proposed.

RESULTS

Idiopathic spinal cord herniation occurs in the middle-aged adult, with a preponderance of patients being female. Brown-Séquard syndrome is the most common clinical presentation and usually progresses to spastic paraparesis. MRI typically shows a ventral kink in the thoracic cord, with MR phase-contrast imaging proving an important addition to exclude an arachnoid cyst. Better outcomes were noted in the patients treated earlier, and in those with no spasticity. Widening the dural defect seems to afford better results compared to grafting of the defect. The prognosis is favorable after correction, though a vertebral body herniation variant may be associated with worse outcome. In view of the chronology of events and imaging studies in our patient, we hypothesize that herniation occurs as an acquired phenomenon where an inflammatory process results in adherence between the spinal cord and the dura, with erosion, formation of a dural defect, and then later herniation occurring with cerebral spinal fluid (CSF) pulsations.

CONCLUSIONS

Idiopathic herniation of the spinal cord should be recognized and treated early to reach a favorable outcome. It seems to be an acquired condition likely caused by an inflammatory event, the nature of which is to be determined.

Case of idiopathic thoracic spinal cord herniation with a chronic history: a case report and review of the literature

Idiopathic spinal cord herniation is a rare disease that presents with slowly progressive myelopathy. This article describes the clinical findings of a patient with a chronic history. A 68-year-old woman initially presented at the age of 32 years with left leg weakness. After slowly progressive neurological deterioration over 34 years, she became completely paraplegic. At the age of 66 years, magnetic resonance imaging resulted in a diagnosis of idiopathic spinal cord herniation at the T6/7 level. Surgery was performed to reduce aching of the lower extremities. The spinal cord was released from the dural defect through a T5-T8 laminectomy. The dural defect was enlarged by resecting its periphery to prevent reherniation of the spinal cord. After the surgery, pain in the lower extremities resolved and her motor function slightly improved. Although operative treatment is naturally recommended at the early stage of this disease, our case suggests that some symptoms can be resolved by surgical treatment despite prolonged, severe preoperative symptoms.

Upper thoracic spinal cord herniation after traumatic nerve root avulsion

✓ Transdural herniation of the spinal cord, a rare but well-documented entity, has been reported sporadically for more than 25 years as a possible cause for various neurological signs and symptoms ranging from isolated sensory or motor findings to myelopathy and Brown–Séquard syndrome. The authors report, to the best of their knowledge, the first case of upper thoracic spinal cord herniation occurring after traumatic nerve root avulsion.

Upper thoracic spinal cord herniation after traumatic nerve root avulsion

✓ Transdural herniation of the spinal cord, a rare but well-documented entity, has been reported sporadically for more than 25 years as a possible cause for various neurological signs and symptoms ranging from isolated sensory or motor findings to myelopathy and Brown—Séquard syndrome. The authors report, to the best of their knowledge, the first case of upper thoracic spinal cord herniation occurring after traumatic nerve root avulsion.