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

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

Introduction

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

Case presentation

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

Conclusion

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

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

Background

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

Case description

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

Conclusion

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

Duroplasty in iatrogenic dorsal spinal cord herniation: illustrative case

BACKGROUND

The case report detailed an unusual presentation of an iatrogenic dorsal cord herniation at the level of the thoracic cord after insertion of an epidural catheter 8 months before presentation to the neurosurgical clinic.

OBSERVATIONS

Only 13 cases of iatrogenic dorsal cord herniation, most of which occurred after spinal surgery, have been described in the literature. This was the first case of a spinal cord hernia described after the insertion of an epidural catheter. In this case study, the authors described a 38-year-old man who presented with progressive lower limb weakness, sensory deficits, perianal numbness, and urinary/fecal incontinence. He was diagnosed with a spinal cord hernia that reherniated after an initial sandwich duroplasty repair. Definitive repair was made after his re-presentation using an expansile duroplasty.

LESSONS

In patients with previous spinal instrumentation who present with neurological symptoms, spinal cord herniation should be considered a likely differential despite its rarity. In this case, a simple duroplasty was insufficient to provide full resolution of symptoms and was associated with recurrence. Perhaps a combination of graft and expansile duroplasty may be used for repair, especially when associated with a tethered cord and in the presence of significant adhesions.

Idiopathic dorsal spinal cord herniation perforating the lamina: a case report and review of the literature

Spinal cord herniation (SCH) is a rare condition associated with tethering of the spinal cord at the ventral dural defect. Idiopathic dorsal spinal cord herniation (IDSCH) is an extremely rare clinical entity. Here, we report the first case of IDSCH perforating the lamina in a patient with a history of ossification of the ligamentum flavum and diffuse idiopathic skeletal hyperostosis. Untethering of the spinal cord was performed by removing the surrounded ossified dura. Although urological symptoms and impaired proprioception remained, progressive neurological deterioration was prevented. Because this disease condition is extremely rare, it should be differentiated from ventral SCH.

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

Idiopathic spinal cord herniation is a rare but important and increasingly recognised cause of myelopathy seen in the thoracic spine. The factors that contribute to the aetiology of the condition and of the dural defect through which the cord herniates remain under debate. We discuss the clinical features and proposed pathophysiology of the condition, and illustrate key imaging findings on MRI, fluoroscopy and computed tomography (CT) myelography to establish the diagnosis, and discuss relevant differential diagnoses. Awareness and recognition of the condition is key as surgical intervention can improve outcomes for patients.

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.

Pathophysiology and Grading of the Ventral Displacement of Dorsal Spinal Cord Spectrum

Study Design

A retrospective study of the ventral displacement of dorsal spinal cord (VDDSC) spectrum pathophysiology and grading.

Purpose

This study aimed at examining the pathophysiology of VDDSC between D3 and D7, using magnetic resonance imaging (MRI) correlation and severity grading.

Overview of Literature

The pathologies that lead to VDDSC were previously discussed in various articles. We attempted to group these pathological conditions under a single spectrum, and grade them according to their severity.

Methods

We reviewed the MRI images of the dorsal spines of 1,350 patients over a period of 4 years (February 2013–February 2017); all MRI images were analyzed by two experienced radiologists.

Results

Of the 1,350 patients, 28 exhibited VDDSC between D3 and D7. Additional findings included ventral transdural herniation of the spinal cord (n=10), anterior spinal cord adhesion (n=7), arachnoid web (n=6), and arachnoid cyst (n=5).

Conclusions

We grouped the pathologies that lead to VDDSC at the thoracic level into a single spectrum of varying severity and graded VDDSC, from mild to severe.

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.

Surgical Management of a Patient With Thoracic Spinal Cord Herniation

BACKGROUND AND IMPORTANCE:

Thoracic spinal cord herniation (TSCH) is rare and likely underdiagnosed. It is characterized by ventral herniation of the spinal cord through a dural defect, effacement of the anterior subarachnoid space, and increased posterior subarachnoid space. We present here a case of TSCH diagnosed and surgically treated at Barrow Neurological Institute, along with supplemental intraoperative video.

CLINICAL PRESENTATION:

A 61-year-old man with a history of progressive myelopathy causing left lower-extremity weakness with associated numbness, impaired gait, foot drop, incontinence, and sexual impotence was referred without any previous treatment. Computed tomographic myelography and magnetic resonance imaging of the thoracic spine showed ventral spinal cord herniation at T3-T4. Neurological monitoring was recorded preoperatively and intraoperatively. The patient underwent left-sided posterolateral exploration via T3-T4 laminectomies and costotransversectomy for intradural cord release/detethering of the spinal cord with additional superior and inferior extension and repair of the dural defect. Arthrodesis was not considered necessary. After cord release, motor evoked potentials showed immediate improvement from baseline. Dural duplication was considered the cause of TSCH in this case. Total reduction of herniation was evident in postoperative images. The postoperative course was uneventful, and at the last follow-up, the patient had regained ambulation and sphincter control.

CONCLUSION:

Anterior displacement of the thoracic spinal cord should elicit consideration of herniation to prevent misdiagnosis and inadequate surgery. Surgical cord release and enlargement of the dural defect are safe and associated with good clinical outcomes.

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.

Idiopathic ventral spinal cord herniation: an increasingly recognized cause of thoracic myelopathy

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

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.

Dorsal thoracic spinal cord herniation: report of an unusual case and review of the literature

BACKGROUND CONTEXT

Spinal cord herniation is a rare but well-documented condition that has been associated with tethering through the dural defect. Both spinal cord herniation and cord tethering result in progressive myelopathy that can be improved or stabilized with surgical intervention. Most cases of herniation are caused by dural defects in the ventral or ventrolateral thoracic spine, rarely occurring through the dorsal dura. This is the first reported case of a spontaneous dorsal herniation.

PURPOSE

To describe a unique case of thoracic tethered cord resulting from a dorsal dural defect through which there is spinal cord herniation.

STUDY DESIGN

A case report and review of the literature.

METHODS

A 55-year-old man presented with progressive low back pain, paresthesias, and weakness in his left lower extremity that was exacerbated by walking. Imaging revealed a dorsal dural defect with tethering and herniation of the spinal cord at T7.

RESULTS

The patient underwent a T6-T7 laminoplasty to release the tethered cord and repair the dural defect. At 1-year follow-up, the patient noted improvement in strength and back spasticity.

CONCLUSIONS

Spinal cord herniation through a dural defect is an uncommon but important cause of symptomatic tethered cord in adults. Surgical intervention can significantly alter the course and prevent further disability.

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.

Unilateral paramedian transpedicular approach for repair of anterior transdural spinal cord herniation: report of a case and literature review

Idiopathic spinal cord herniation is a rare but potentially treatable cause of thoracic myelopathy. The rarity and variable clinical presentation often results in missed diagnosis and delay in treatment. Posterior midline approach with laminectomy has been the most common approach performed for spinal cord herniation in cases described in the literature. A posterior approach is limited by the danger of retracting the spinal cord and difficulty visualizing the dural defect. Considering the anterior location of the dural defect, a posterolateral allows for a more ventral view without spinal cord manipulation. We report a rare case of idiopathic spinal cord herniation which was managed by unilateral paramedian transpedicular approach with an excellent clinical outcome.

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.