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

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.

Idiopathic spinal cord herniation with postoperative paraplegia-A case report

Key clinical message

Spinal cord herniation is an uncommon diagnosis. There should be a high index of suspicion to diagnose spinal cord herniation when a patient presents with incomplete neurological deficits. Surgical repair of the hernia can have postoperative complications with new neurological deficits and they should be considered during the treatment.

Abstract

A 37-year-old male presented with insidious onset upper back pain and altered sensations of pain and temperature over the right half of the body below the nipple for 2 months. MRI of the thoracic spine showed an anterolateral defect (left) at the level of T2-T3 vertebra. The defect was covered by a dural graft and the wound was closed with a drain On the 3rd postoperative day, neurological weakness progressed to paraplegia. Patient was treated by exploration and decompression of the hematoma. The deficits were completely recovered at one-month follow-up. Patients with spinal cord herniation and neurologic deficits when treated timely have good outcomes.

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.

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.

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.

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.

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.

Spontaneous resolution of idiopathic thoracic spinal cord herniation: case report

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

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.

Surgical manifestations of thoracic arachnoid pathology: series of 28 cases

Object

Various pathologies involving the thoracic arachnoid mater uniformly manifest as thoracic myelopathy and may present a significant management dilemma. The authors undertook this study to assess outcome in cases of thoracic myelopathy due to thoracic arachnoid pathology.

Methods

The authors have cared for and followed 28 patients with thoracic myelopathy from thoracic arachnoid pathology over the last 17 years. A chart review and contemporary follow-up of these patients was performed and outcomes were reported.

Results

Patients with thoracic myelopathy from thoracic arachnoid pathology often have improvement in their condition after surgical decompression/detethering procedures. While not universal, patients in this series had improvement in mJOA scores at 1 year after surgery (p = 0.0001) and at last follow-up (p = 0.04). Results indicated that across a wide variety of pathologies the extent of thoracic spinal cord involvement is a predictor of the disease course and outcome. Comparison of the group of patients with cord involvement limited to 2 vertebral segments (short-segment pathology) versus the group with cord tethering of more than 2 segments (long-segment pathology) showed that patients in the short-segment group more frequently had ventral or dorsal arachnoid bands (p = 0.003), more frequently had signal change in the cord on MRI (p = 0.02), and less frequently presented with a syrinx (p = 0.02), and a smaller percentage of patients in this group underwent reoperation (p = 0.02). While patients with short-segment pathology typically improved after a single operative intervention, patients with long-segment pathology typically improved after multiple operations, frequently for CSF diversion.

Conclusions

Thoracic arachnoid pathology causing thoracic cord dysfunction and myelopathy is varied, has multiple etiologies, and can be difficult to treat over the long term. Surgical management, when indicated, is case specific. Serial long-term follow-up is essential to document enduring clinical and radiographic success.

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.

Surgical technique for idiopathic spinal cord herniation: the Hammock method. Technical note

Idiopathic spinal cord herniation is a rare disease, and surgical treatment is recommended for patients with motor deficits or progressive neurological symptoms. Surgery is performed to release and reposition the tethered spinal cord. In terms of repositioning and prevention of reherniation, various procedures have been proposed; enlargement of the ventral dural defect, primary closure of the defect with sutures, and insertion of a ventral patch for duraplasty. We treated 3 patients with idiopathic spinal cord herniation, using a ventral patch for duraplasty with an expanded polytetrafluoroethylene pericardial membrane (the Hammock method), and all 3 cases had good clinical outcome. The specific important technical aspects are described and illustrated. If this procedure is performed meticulously under the microscope by following the specific techniques, the Hammock method is safer and more effective for prevention of reherniation than simple enlargement of the dural defect.

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.

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.

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.

Spontaneous spinal cord herniation: recurrence after 10 years

BACKGROUND CONTEXT

Transdural spontaneous spinal cord herniation is a very rare nosological entity, which despite recent reports in the medical literature remains often misdiagnosed preoperatively. Usually it affects the thoracic segment, protrudes ventrally, presents clinically as a progressive Brown-Séquard syndrome and carries a favorable surgical outcome.

PURPOSE

To describe a rare case of delayed recurrence of spontaneous spinal cord herniation despite excellent outcome for 10 years, and discussion of management and observation issues.

STUDY DESIGN/SETTING

Case report/University Hospital.

METHODS

We describe the management of a patient with spontaneous spinal cord herniation that presented initially with a Brown-Séquard syndrome and has been treated successfully with surgery. After 10 years free of symptoms, the patient developed progressive paraparesis and urinary incontinence because of recurrence of the herniation at the same level.

RESULTS

Despite technical challenges, during the second operation the enlarged ventral dural defect was meticulously closed and the patient's neurological condition presents 9-month postsurgery considerable improvement. To our best knowledge, recurrences of spontaneous spinal cord herniation are extremely rare.

CONCLUSIONS

The reported case underlines the necessity to be aware of this rare but treatable spinal disease, notify the possibility of late recurrences and the need of long-term follow-up even if initial outcome is favorable.

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.

Ventral Thoracic Spinal Cord Herniation: A Commonly Misdiagnosed and Treatable Cause of Myelopathy

Idiopathic ventral spinal cord herniation is a rare cause of progressive myelopathy that demonstrates unique radiological features. We describe a case of thoracic spinal cord herniation through an anterior dural defect and discuss the characteristic findings on magnetic resonance imaging and computed tomographic myelography. A 36-year-old man presented to our clinic with progressive leg weakness and spasticity in both legs. Magnetic resonance imaging of the thoracic spinal canal demonstrated C-shaped anterior kinking of an atrophied spinal cord and enlarged dorsal subarachnoid space at the T5-T6 level. Computed tomographic myelography showed ventral herniation of the spinal cord and no evidence of an intradural spinal arachnoid cyst. Ventral spinal cord herniation is a commonly misdiagnosed entity. Knowledge of the characteristic imaging appearance of this treatable condition is important for proper diagnosis and treatment.

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.

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.