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

Unveiling the Current Understanding of Idiopathic Spinal Cord Herniation: A Systematic Review

Background

Idiopathic spinal cord herniation (ISCH) is a rare condition that is characterized by ventral herniation of the spinal cord through a defect in the dura mater into the epidural space, with no identifiable cause. ISCH is frequently underdiagnosed, and the information available in case reports is limited. To provide an overview of the clinical manifestations and diagnosis of this condition, this study aims to conduct a review of reported cases of ISCH.

Methods

A literature review was carried out using seven databases. The search was conducted using the keywords "Idiopathic spinal cord herniation" OR "Idiopathic Ventral Spinal Cord Herniation" AND "Case report" OR "case series."

Results

A total of 92 relevant papers reporting 224 cases, besides the index case, were determined. Of the cases, 58.5% were females and the mean age was 50.7 (SD 13.2) years. Symptoms, diagnoses, and outcomes were similar between genders. The most common clinical signs included motor symptoms (82.6%), instability (61.3%), hypoesthesia (59.2%), and disturbance of thermal sensitivity (47.3%). Brown-Séquard syndrome was observed in 27.2% of the cases, and surgical treatment was employed in 89.7% of the cases.

Conclusions

ISCH is a pathology that is principally treated with surgical approach. This study provides valuable insights into the clinical manifestations and diagnosis of ISCH, which can aid in the early recognition and treatment of this rare condition.

Natural history and surgical outcomes of idiopathic spinal cord herniation

STUDY DESIGN

Retrospective multicenter study.

OBJECTIVES

Although surgery is frequently selected for the treatment of idiopathic spinal cord herniation (ISCH), its impact on functional outcomes has yet to be fully understood given the limited number of patients in previous studies. This study aims to evaluate the symptomatic history and surgical outcomes of ISCH.

SETTING

Three institutions in Japan.

METHODS

A total of 34 subjects with ISCH were retrospectively enrolled and followed up for at least 2 years. Demographic information, imaging findings, and clinical outcomes were collected. Functional status was assessed using the JOA score.

RESULTS

The types of neurologic deficit were monoparesis, Brown-Sequard, and paraparesis in 5, 17, and 12 cases, with their mean disease duration being 1.2, 4.2, and 5.8 years, respectively. Significant differences in disease duration were observed between the monoparesis and Brown-Sequard groups (p < 0.01) and between the monoparesis and paraparesis groups (p = 0.04). Surgery promoted significantly better recovery rates from baseline. Correlations were observed between age at surgery and recovery rate (p < 0.01) and between disease duration and recovery rate (p = 0.04). The mean recovery rates were 82.6%, 51.6%, and 29.1% in the monoparesis, Brown-Sequard, and paraparesis groups, respectively. The monoparesis group had a significantly higher recovery rate than did the Brown-Sequard (p = 0.045) and paraparesis groups (p < 0.01).

CONCLUSIONS

Longer disease duration was correlated with the progression of neurologic deficit. Older age, and worse preoperative neurologic status hindered postoperative functional recovery. These results highlight the need to consider surgical timing before neurologic symptoms deteriorate.

Symptomatic interdural cerebrospinal fluid collections after surgery for idiopathic spinal cord herniation: illustrative case

BACKGROUND

Idiopathic spinal cord herniation (ISCH) is very rare. Some reports have described postoperative ventral cerebrospinal fluid (CSF) collections in patients with ISCH; however, such collections are asymptomatic in most patients, and there is no consensus regarding whether they are part of the natural history or a complication.

OBSERVATIONS

A 30-year-old man with ISCH underwent direct closure of a duplicated dura mater. Eight months postoperatively, he developed reworsening of right lower limb paresis and new severe right arm pain and paresis. Three-dimensional magnetic resonance imaging revealed ventral CSF collections, which the authors judged as the responsible lesions. The authors initially considered these collections to be present in the epidural space, extradurally compressing the dural sac and resulting in myelopathy. An epidural blood patch failed; however, a CSF drainage test resulted in dramatic improvement. The authors therefore determined that the CSF collections were located in the interdural space, not the epidural space. A lumboperitoneal (LP) shunt was performed to reduce the CSF pressure. The patient’s symptoms improved immediately postoperatively. He had developed no recurrence of symptoms 6 months after surgery.

LESSONS

Ventral interdural CSF collections after ISCH surgery can cause reworsening of myelopathy and may be cured by a LP shunt to control CSF pressure.

Operative versus Nonoperative Management of Idiopathic Spinal Cord Herniation: Effect on Symptomatology and Disease Progression

BACKGROUND

Idiopathic spinal cord herniation (ISCH) is a rare pathology characterized by extravasation of the spinal cord through a dural defect. The optimal algorithm for choosing operative or nonoperative management is not well elucidated, partially because of the rarity of this pathology. We present the largest single-center series of ISCH and compare operative treatment to conservative management.

METHODS

A retrospective case series of all patients evaluated for treatment of ISCH at our institution between 2010 and 2019 was conducted. Demographic variables, presenting symptoms, and imaging characteristics were assessed for all patients. For patients who underwent operative treatment, surgical approach, postoperative course, and discharge outcomes were recorded. Follow-up notes were reviewed for status of symptoms and functional capabilities, which were synthesized into Odom's criteria score.

RESULTS

Sixteen patients met the inclusion criteria for this study, 8 of whom underwent operative treatment. No significant differences were found between operative and nonoperative groups with regard to demographic variables or pathology characteristics. Odom's criteria scores for the operative cohort were 12.5% (1 of 8) Excellent, 62.5% (5 of 8) Good, 12.5% (1 of 8) Fair, and 12.5% (1 of 8) Poor. Odom's criteria scores for the nonoperative cohort were 16.7% (1 of 6) Excellent, 33.3% (2 of 6) Good, 16.7% (1 of 6) Fair, and 33.3% (2 of 6) Poor. There was no significant difference between Odom's criteria score distribution between the operative and nonoperative groups at latest follow up (P = 0.715).

CONCLUSIONS

Conservative management of spinal cord herniation is an option that does not preclude symptomatic improvement in patients with idiopathic spinal cord herniation.

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.

Single-centre study comparing surgically and conservatively treated patients with spinal cord herniation and review of the literature

Introduction

Spinal cord herniation (SCH) is a rare cause of progressive myelopathy and Brown-Séquard-Syndrome.

Research question

Evaluation of functional outcome after SCH treatment compared to conservatively treated patients.

Material and methods

We retrospectively analysed functional outcome in SCH patients treated between 2009 and 2020. We conducted a systematic search using PubMed, MEDLINE and EMBASE to perform a pooled analysis in SCH patients.

Results

Our hospital cohort included 17 patients of which 9 were treated surgically. Mean age was 51.9 years, 58.8% of the patients were female. In 4/9 patients (44.4%) the neurological state remained stable after surgery. Four patients improved (44.4%) and one deteriorated after surgery (11.1%). Conservatively treated patients had a higher deterioration rate on follow-up with 3/8 patients deteriorating (37.5%). In our pooled analysis, 109/145 (75.2%) of patients improved, 32/145 (22.1%) remained stable and 4/145 patients deteriorated (2.8%). Among the available data of nine cohorts, mean recovery rate measured by the JOA score was 36.6% (SD 14.4). In our pooled multivariable model lower preoperative JOA score was associated with worse functional outcome (OR 0.86, 95%CI 0.74–0.99, p ​= ​.04).

Discussion and conclusion

Our data shows that patients who are treated surgically have a higher improvement rate and acceptable perioperative morbidity compared to conservatively treated patients. Lower preoperative JOA score decreases chances of improved functional outcome on follow-up. We therefore advocate early surgery for symptomatic patients. Wait and see appears outdated due to progressive impairment and decreased chances of recovery. However, it is still an option in asymptomatic incidental SCH patients.

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Evaluation of 17 patients with myelon herniation, 9 undergoing surgical treatment, 8 choosing conservative treatment.

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In the surgically treated group, 44.4% improved after surgery compared to none in the conservative group.

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11.1% deteriorated in the surgically treated compared to 37.5% in the conservatively treated group.

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Surgically treated patients have a higher improvement rate.

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Lower preoperative JOA score is associated with less improvement advocating early surgery in symptomatic patients.

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.

Late Cervical Spinal Cord Herniation Resulting from Post-Traumatic Brachial Plexus Avulsion Injury

BACKGROUND

Spinal cord herniation (SCH) is often described as occurring spontaneously in the thoracic spine, with few cases of cervical SCH reported as a late complication of traumatic brachial plexus avulsion. We present 2 cases of nerve root avulsion and pseudomeningocele formation, resulting in delayed cervical SCH and neurologic deterioration.

CASE DESCRIPTION

Case 1: A 37-year old man presented with progressive leg weakness 2 years after experiencing traumatic C8 and T1 root avulsions. Magnetic resonance imaging (MRI) showed previously documented C8-T1 nerve avulsions with new SCH in a T1 pseudomeningocele. A C7-T1 costotransversectomy and C4-T4 instrumented fusion were completed, allowing SCH reduction and patch graft repair of the dural defects without the need for adhesiolysis. At last follow-up, the patient's leg weakness had resolved. Case 2: A 32-year old man presented with progressive right arm numbness, weakness, and signs of myelopathy 9 years after experiencing C8 and T1 root avulsions. MRI showed previously documented root avulsions and new SCH with extensive and compressive pseudomeningocele formation. A C7 transpedicular approach with C5-T1 instrumented fusion was completed for dural repair. A large pseudomeningocele was found and drained on drilling the C7 pedicle, and adhesiolysis was required at the spinal cord avulsion site to reduce the SCH and allow patch graft repair. At last follow-up, the patient's right arm weakness was improving, although numbness persisted.

CONCLUSIONS

SCH is a rare cause of delayed neurologic deterioration after brachial plexus avulsion, with few case reports describing its occurrence. We present 2 cases of this complication and describe its successful surgical treatment through dural repair after instrumented fusion.

Thoracic idiopathic spinal cord herniation in a young patient: a diagnostic and therapeutic challenge

Idiopathic Spinal Cord Herniation (ISCH) is considered to be a rare cause of Thoracic Myelopathy. It is secondary to the gliding of the Spinal Cord through an anterior dural defect, without a completely defined cause. We present a case of ISCH which, even though was in its usual location, developed in a woman at a younger age than expected. The patient was 20 years old when diagnosed with Brown-Séquard Syndrome. MRI showed herniation at T4-T5 level, which was corrected using a posterior approach to expose the dural defect, reduce the herniation and place a heterologous graft. Postoperatively, neurological function improved, and adequate reduction was seen on imaging. Given the reports of recurrence and deterioration that have been seen after 18 months, follow-up was prolonged for a total of 2 years. We consider postoperative MRI performance important to establish the degree of reduction and alignment of the Spinal Cord.

Duplication of Ventral Dura as a Cause of Ventral Herniation of Spinal Cord-A Report of Two Cases and Review of the Literature

BACKGROUND

Idiopathic spinal cord herniation (ISCH) is a treatable spinal disease. It is rare and often misdiagnosed, causing a delay in management. The etiology is multifactorial, with one of the causes being duplication of the ventral dura. The spinal cord herniates within this defect and becomes strangulated, causing neurological deficits. We report the duplication of a ventral spinal cord as an important cause of ISCH in our review.

CASE DESCRIPTION

We present 2 cases of ISCH with duplication of the dura, including their relevant clinical and imaging features. The patients underwent surgical reduction of the herniated spinal cord with enlargement of the defect and placement of a dural substitute ventral to the cord. We have also reported the outcomes of the 2 patients, with an emphasis on the factors predictive of poor outcomes (i.e., long-standing symptoms, a delay in intervention, poor neurological status at presentation, and a thinned out atrophic spinal cord found during surgery). We also reviewed the available data for duplication of the dura with ISCH.

CONCLUSIONS

Very few asymptomatic patients can be treated conservatively. The surgical outcomes have been favorable for symptomatic patients. Proper exposure, gentle manipulation while reducing the herniated spinal cord, enlargement of the defect, and the use of intraoperative monitoring will help limit the postoperative deficits. Duplication of the ventral dura is an important cause of ISCH. It prevents the formation of an anterior pseudomeningocele after surgery. Owing to the rarity of the disease and the lack of follow-up data with recurrence rates, it has not been possible to form clear guidelines for management.

Operative Management of Idiopathic Spinal Cord Herniation: Case Series and Novel Technique for Repair of Recurrent Herniation

BACKGROUND

Idiopathic spinal cord herniation (ISCH) is a rare pathology of the spine defined by herniation of the spinal cord through a dural defect.

OBJECTIVE

To highlight the operative management of ISCH and the surgical nuances of ISCH repairs conducted at our institution.

METHODS

This retrospective review examines consecutive patients with ISCH who were treated surgically between January 1, 2010, and July 31, 2017, at Barrow Neurological Institute, Phoenix, Arizona.

RESULTS

Four patients with ISCH presented with thoracic myelopathy and lower extremity weakness during the study period. Treatment consisted of reduction of the herniated spinal cord and filling of the dural defect with a collagen-based dural regeneration matrix. In 3 patients the dural edges were covered with a collagen-matrix intradural sling, and in 1 patient they were repaired primarily with interrupted sutures. Three of the 4 patients experienced improvement in myelopathic symptoms; the fourth patient suffered neurological decline in the immediate postoperative period.

CONCLUSION

ISCH is a complex pathological condition likely to result in progressive myelopathy. Surgery offers patients the possibility of stabilizing the progression of the spinal cord dysfunction and perhaps restoring neurological function. However, extreme care must be taken during surgery to minimize manipulation of the fragile herniated cord.

Spinal Cord Suspension Using Dentate Ligament Hitch Stitches: A Novel Technique for the Repair of Ventral Spinal Cord Herniation

BACKGROUND

Idiopathic spinal cord herniation is usually repaired by releasing the spinal cord and inserting a dural patch to close the herniated segment of dura. However, reherniation is a potential limitation of this standard technique.

OBJECTIVE

To describe early results of a novel technique that utilizes the dentate ligament to hitch the spinal cord and prevent reherniation.

METHODS

Two patients underwent dural hernia repair and the dentate hitch technique was performed.

RESULTS

Restored lower limb power and mobility, and satisfactory reduction of spinal cord herniation on magnetic resonance imaging in 2 patients at 6- and 24-mo follow-ups, respectively.

CONCLUSION

The dentate hitch technique can achieve repair of spinal cord herniation, with satisfactory postoperative results and minimizes the risk of reherniation.

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.

Idiopathic spinal cord herniation: consideration of its pathogenesis based on the histopathology of the dura mater

INTRODUCTION

We present a patient with idiopathic spinal cord herniation (ISCH) whose dura mater was histopathologically examined to elucidate its pathogenesis.

CASE REPORT

A 33-year-old previously healthy man presented with progressive walking difficulty, spasticity of the right lower leg, and hyperesthesia below the right chest. Neuroimaging revealed right ventral displacement of the spinal cord at T5-6. The diagnosis was ISCH and he underwent release of the herniation from the ventral dural opening. Dural biopsy at the edge of the ventral opening and in the dorsal durotomy was performed. Postoperatively, his gait was improved. Histopathological examination of the ventral dural specimen showed non-specific degeneration, i.e., loose arrangements of collagen fibers, edematous changes, minor inflammatory cell infiltration, and angiogenesis. The specimen from the dorsal durotomy was normal.

CONCLUSION

It is unclear whether the observed degeneration besides the ventral opening was the primary cause of ISCH or reflected secondary changes resulting from cumulative damage due to pulsation of the herniated spinal cord. However, the degeneration limited to the ventral opening suggests that ISCH was a local event in an individual with a normal dural theca.

A New Classification for Pathologies of Spinal Meninges, Part 1: Dural Cysts, Dissections, and Ectasias

BACKGROUND: The clinical significance of pathologies of the spinal dura is often unclear and their management controversial.

OBJECTIVE: To classify spinal dural pathologies analogous to vascular aneurysms, present their symptoms and surgical results.

METHODS: Among 1519 patients with spinal space-occupying lesions, 66 patients demonstrated dural pathologies. Neuroradiological and surgical features were reviewed and clinical data analyzed.

RESULTS: Saccular dural diverticula (type I, n = 28) caused by defects of both dural layers, dissections between dural layers (type II, n = 29) due to defects of the inner layer, and dural ectasias (type III, n = 9) related to structural changes of the dura were distinguished. For all types, symptoms consisted of local pain followed by signs of radiculopathy or myelopathy, while one patient with dural ectasia presented a low-pressure syndrome and 10 patients with dural dissections additional spinal cord herniation. Type I and type II pathologies required occlusion of their dural defects via extradural (type I) or intradural (type II) approaches. For type III pathologies of the dural sac no surgery was recommended. Favorable results were obtained in all 14 patients with type I and 13 of 15 patients with type II pathologies undergoing surgery.

CONCLUSION: The majority of dural pathologies involving root sleeves remain asymptomatic, while those of the dural sac commonly lead to pain and neurological symptoms. Type I and type II pathologies were treated with good long-term results occluding their dural defects, while ectasias of the dural sac (type III) were managed conservatively.

Surgical management of thoracic idiopathic spinal cord herniation. Technical case report and review

Idiopathic spinal cord herniation (ISCH) is a rare spinal disease, in which chronic cerebrospinal fluid pulsations push the arachnoid and adjacent thoracic spinal cord region through an antero-lateral dural defect of congenital, post-traumatic, or inflammatory/erosive origin. Symptomatic patients commonly present around the 5th decade of life with slowly progressive myelopathy. Diagnosis relies on high-resolution magnetic resonance imaging. Stable mild cases may be observed, whereas in progressive symptomatic situations, surgical spinal cord reposition and dural defect repair with a dural patch is the preferred treatment. We present a case of ISCH at T5/6 and a review the literature.

Spontaneous Anterior Thoracic Spinal Cord Herniation through Dura Defect: A Case Report

Thoracic spinal cord herniation is a rare disease cause of progressive myelopathy. Magnetic resonance image is a useful tool to diagnose preoperatively. Operation is a treatment of option. Sixty-six-year-old female visited Dong-A University Medical Center for progressive gait disturbance with falling tendency to right side. She had radiating pain and tingling sense on both leg. Sense of touch and temperature was decreased below T6 level. Both hip and knee motor power were grade IV. Magnetic resonance imaging scan showed anterior displacement of the spinal cord at T4-T5 vertebral level. Under the diagnosis of thoracic spinal cord herniation with dura defect, operation was performed for the patient with intraoperative neuromonitoring. Laminectomy at T4 and T5 level was done, and intradural exploration of the spinal cord revealed dura defect about 25mm×8mm in size. Spinal cord was released under microscope and dura defect was repaired with Lyoplant. The patient's symptom improved after the surgical procedure, but touch and temperature sense under T6 level had unchanged.

Postoperative MR Imaging of Spontaneous Transdural Spinal Cord Herniation: Expected Findings and Complications

BACKGROUND AND PURPOSE

Spontaneous transdural spinal cord herniation is no longer a rare cause of myelopathy. The high frequency of diagnoses has led to an increase in the number of surgical procedures. The purpose of this study was to describe the spectrum of postoperative MR imaging findings concerning spontaneous transdural spinal cord herniation and to provide a practical imaging approach for differentiating expected changes and complications after an operation.

MATERIALS AND METHODS

We retrospectively reviewed MR images from 12 patients surgically treated for spontaneous transdural spinal cord herniation. Surgery comprised either dural defect enlargement or duraplasty procedures. Postoperative follow-ups included at least 3 (early, intermediate, late) MR imaging studies. MR images were analyzed with respect to 3 spinal compartments: intradural intramedullary, intradural extramedullary, and extradural. The meaning and reliability of changes detected on MR images were related to their radiologic and clinical evolution with time.

RESULTS

Spinal cord realignment has been stable since the early study, whereas spinal cord signal and thickness evolved during the following scans. Most extramedullary and extradural changes gradually reduced in later MR images. Three patients treated with dural defect enlargements experienced the onset of new neurologic symptoms. In those patients, late MR images showed extradural fluid collection and the development of pial siderosis.

CONCLUSIONS

Our findings demonstrate the spectrum of postoperative imaging findings in spontaneous transdural spinal cord herniation. Spinal cord thickness and signal intensity continued to evolve with time; most extramedullary postsurgical changes became stable. Changes observed in later images may be suggestive of complications.

Symptomatic thoracic spinal cord herniation: case series and technical report

BACKGROUND AND IMPORTANCE

Idiopathic spinal cord herniation (ISCH) is an uncommon condition located predominantly in the thoracic spine and often associated with a remote history of a major traumatic injury. ISCH has an incompletely described presentation and unknown etiology. There is no consensus on the treatment algorithm and surgical technique, and there are few data on clinical outcomes.

CLINICAL PRESENTATION

In this case series and technical report, we describe the atypical myelopathy presentation, remote history of traumatic injury, radiographic progression, treatment, and outcomes of 5 patients treated at Washington University for symptomatic ISCH. A video showing surgical repair is presented. In contrast to classic compressive myelopathy symptomatology, ISCH patients presented with an atypical myelopathy, characterized by asymmetric motor and sensory deficits and early-onset urinary incontinence. Clinical deterioration correlated with progressive spinal cord displacement and herniation observed on yearly spinal imaging in a patient imaged serially because of multiple sclerosis. Finally, compared with compressive myelopathy in the thoracic spine, surgical treatment of ISCH led to rapid improvement despite a long duration of symptoms.

CONCLUSION

Symptomatic ISCH presents with atypical myelopathy and slow temporal progression and can be successfully managed with surgical repair.

The pathophysiology, classification, treatment, and prognosis of a spontaneous thoracic spinal cord herniation: A case study with literature review

Background:

Spinal cord herniation was first described in 1974. It generally occurs in middle-aged adults in the thoracic spine. Symptoms typically include back pain and progressive paraparesis characterized by Brown-Séquard syndrome. Surgical reduction of the hernia improves the attendant symptoms and signs, even in patients with longstanding deficits.

Case Description:

A 66-year-old female with back pain for 7 years, accompanied by paresthesias and a progressive paraparesis, underwent a thoracic MRI which documented a ventral spinal cord herniation at the T4 level. Following a laminectomy, with reduction of the hernia and ventral dural repair, the patient improved.

Conclusion:

Herniation of the thoracic cord, documented on MR, may produce symptomatic paraparesis which may resolve following laminectomy with ventral dural repair.

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 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.

Long-term surgical outcomes of idiopathic spinal cord herniation

BACKGROUND

Because of the lack of long-term postoperative follow-up studies of idiopathic spinal cord herniation (ISCH), there is little information about the long-term effectiveness and complications of the dural defect enlargement in patients with ISCH. The purpose of this study is to determine the long-term effectiveness of this procedure.

METHODS

Sixteen patients with ISCH were treated surgically by enlargement of the dural defect. The patient's neurological status and surgical outcome were evaluated by the JOA scores for thoracic myelopathy and the recovery rate (mean follow-up period 9.6 years). Correlations between the surgical outcomes and patients' age and duration of disease were assessed retrospectively. The patients were also divided into two groups based on the location of the dural defect: the ventro-lateral (VL) group and the ventral (V) group. The difference in the duration of disease, preoperative JOA score, and the recovery rate were compared between the two groups.

RESULTS

There was no recurrence of ISCH after surgery. The mean recovery rate was 42.6%. There was a significant correlation between the patient's age and the recovery rate, and between the duration of disease and the recovery rate. The median recovery rate was significantly lower in the V group than in the VL group. There were no complications related to CSF leakage after surgery.

CONCLUSIONS

Long-term surgical outcomes of enlargement of the dural defect for ISCH were stable and favorable without recurrences or any complications. This procedure should be considered for patients with ISCH before their neurological deficit worsens, especially for the patients in whom the dural defect is located at the ventral part of the dural canal.

Spinal cord herniation: a misdiagnosed and treatable cause of thoracic myelopathy

This study is a case report and review of the literature. Spinal cord herniation is a rare, although increasingly recognized, cause of spinal cord dysfunction. It is due to an anterior dural defect, through which the spinal cord herniates. The purpose of this article is to report the authors' experience and to provide insight on clinical presentation and radiological signs to make the reader aware of this entity and then to prevent misdiagnosis. The authors conducted a retrospective review of patients who underwent surgery for spinal cord herniation at their institution between 2000 and 2008. Three patients were treated (all women) and the interval between the onset of symptoms and surgery ranged from 24 to 48 months. All patients had progressive signs of thoracic myelopathy, and two of them were initially misdiagnosed. In all cases, the herniation was reduced and the defect repaired using different methods. The results and complications of our cases were compared with that of the reported literature. According to the results in these cases and the review of the literature, the authors believe that spinal cord herniation should be treated by using a dural patch to close the dural defect and to prevent retethering of the spinal cord.

Thoracic transdural spinal cord herniation at a level caudal to prior discectomy

To outline a scenario of acquired transdural spinal cord herniation not previously described. The authors report their experience with a patient found to harbor a thoracic transdural spinal cord herniation at the disk space immediately caudal to a prior discectomy. Documentation of the radiographic progression of this patient's spinal cord herniation is presented, spanning the course of 13 years. The patient underwent intradural repair of his dural defect via a lateral extracavitary approach. The herniated spinal cord was successfully reduced. The patient had modest improvement in his symptoms at 2-year follow-up. To the best of the authors' knowledge, this case represents the first reported case documenting this anomaly at a level adjacent to that of a previous surgery within the thoracic spine.

Thoracic spinal cord herniation in a patient with long-standing ankylosing spondylitis

The objective of this study was to describe an adult male patient with ankylosing spondylitis (AS) associated with thoracic spinal cord herniation (TSCH). TSCH is a scarce entity presented as a displacement of thoracic cord through an anterior or anterolateral dural defect. More importantly, the co-occurrence of AS and thoracic spinal cord herniation is exceptional. To date, only one case of SCH in association with AS has been reported in the literature. A 56-year-old male patient presented with the progressive difficulty in walking and numbness of both lower limbs for the past 18 months. The patient was diagnosed as AS when he was 30 years old. Sagittal MRI of thoracic spine showed dural defect of the posterior aspect of T11 and 12 vertebral bodies. Axial T2-weighted MRI demonstrated that spinal cord was displaced ventrally and to the right. The diagnosis of TSCH with AS was established. The prognosis was explained to the patient. We recommended duraplasty for dural repair to the patient, but he refused surgery. The results demonstrated that TSCH associated with long-standing AS was very uncommon, and MRI is recommended to rule out SCH in the long-standing AS patients with neurologic symptoms. The SCH in AS might be caused by inflammation, and thoracolumbar hyperkyphosis results from AS might be associated with the development of SCH.

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.

Thoracic cord herniation through a dural defect: description of a case and review of the literature

BACKGROUND

Spinal cord herniation through a dural defect is a cause of myelopathy and BSS that may be underdiagnosed. It may occur spontaneously, after trauma, or after surgery.

CASE DESCRIPTION

We present the case of a 47-year-old woman who presented with low back pain, progressive myelopathy, right proximal LEW, several episodes of falling, sensory changes below the lower part of the chest wall, and pathologic reflexes. Magnetic resonance imaging of the thoracic spine showed kinking of the spinal cord anteriorly at the level of T6-7. Posterior laminoplasty and intradural exploration revealed an anteriorly displaced spinal cord that was herniating through a ventral dural fold. The defect was repaired, and the spinal cord abnormality was reduced. Postoperatively, the patient's strength, gait, and sensation improved immediately.

CONCLUSIONS

We discuss the successful surgical treatment of a thoracic spinal cord tethering from herniation through a ventral dural defect and review the literature regarding the proposed pathogenesis, surgical repair options, and reported outcomes.

Idiopathic spinal cord herniation as a treatable cause of progressive brown-sequard syndrome

Idiopathic spinal cord herniation is a rare spinal cord disorder caused by spinal cord prolapse through a adural defect. It is a curable disease, so early detection is of particular importance. We report a 38-year-old woman with Brown-Sequard syndrome which was caused by the thoracic spinal cord herniation. Her weakness was almost completely resolved after surgical management, which emphasizes the importance of early diagnosis and surgical management in this rare disease entity.

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.