Ventral thoracic spinal cord herniation: frequently misdiagnosed entity

Idiopathic thoracic spinal cord herniation into the vertebra progressing for 3 years

A 43-year-old, previously healthy man experienced a decreased sensation in the left lower extremity without preceding spinal trauma. At presentation, the patient exhibited slight motor weakness in the left lower extremity, in addition to decreased pain sensation below the ipsilateral T7. Spinal magnetic resonance imaging (MRI) revealed abnormal findings consistent with idiopathic thoracic spinal cord herniation (ITSCH) at the T5/6 level. Computed tomography (CT) revealed a small vertebral erosion at the lower T5. The patient's symptoms gradually progressed over the next 3 years. MRI revealed marked lateral elongation of the cord at the T5/6 and apparent intravertebral cord herniation. The patient underwent ITSCH reduction through T5-6 laminectomies. The herniated cord was vertically long with a bulbous rostral part. Successful ITSCH reduction was achieved and the patient's postoperative course was uneventful. ITSCH is a progressive pathology that requires prompt surgical reduction. Certain ITSCHs may be complicated by intravertebral cord herniation.

Thoracic Anterior Spinal Cord Herniation: Treatment and Prognosis Outcome of Seven Patients

BACKGROUND

This study aimed to investigate the diagnosis and treatment of thoracic anterior spinal cord herniation, a rare condition.

METHODS

Clinical data of 7 patients diagnosed with thoracic anterior spinal cord herniation were analyzed. All patients were diagnosed with a complete preoperative examination and scheduled for surgical treatment. In addition, regular follow-up was performed after the surgery, and the operation's efficacy was evaluated according to clinical symptoms, imaging findings, and improvement in neurologic function.

RESULTS

All patients underwent spinal cord release with an anterior dural patch. Notably, no severe postoperative surgical complications were observed. All patients were followed up for 12-75 months, with an average duration of approximately 46.5 months. Post-operative pain symptoms were controlled, neurological dysfunction and related symptoms improved to varying degrees, and anterior spinal cord herniation did not recur. The modified Japanese Orthopedic Association score at the last follow-up was significantly higher than the preoperative score.

CONCLUSIONS

Clinicians should avoid misdiagnosing patients with thoracic anterior spinal cord herniation with intervertebral disc herniation, arachnoid cysts, and other related diseases, and patients should undergo surgical treatment as early as possible. In addition, surgical treatment can protect the neurologic function of patients and effectively prevent the aggravation of clinical symptoms.

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.

Idiopathic Ventral Spinal Cord Hernia-A Single-Center Case Series of 11 Patients

BACKGROUND

Idiopathic spinal cord herniations (ISCH) are rare defects of the ventromedial or mediolateral dura mater with herniation of the spinal cord through the defect with approximately 350 described cases worldwide. Patients usually become symptomatic with motor or sensory neurological deficits and gait disturbances.

OBJECTIVE

To describe characteristic symptoms and clinical findings and to evaluate the postoperative course and outcomes of ISCH.

METHODS

We present a single-center data analysis of a case series of 11 consecutive patients who were diagnosed with ISCH and underwent surgery in our department between 2009 and 2021.

RESULTS

All herniations were located in the thoracic spine between T2 and T9. In most cases, gait ataxia and dysesthesia led to further workup and subsequently to the diagnosis of ISCH. A "far-enough" posterior-lateral surgical approach, hemilaminectomy or laminectomy with a transdural approach, was performed under intraoperative neurophysiological monitoring which was followed by adhesiolysis, repositioning of the spinal cord and sealing using a dura patch. After surgery, clinical symptoms improved in 9 of 11 patients (81.8%), while only 1 patient experienced deterioration of symptoms (9.1%) and 1 patient remained equal (9.1%). The median preoperative McCormick grade was 3 (±0.70), while the median postoperative grade was 2 (±0.98) ( P = .0047).

CONCLUSION

In our case series of ISCH, we found that in most patients, neurological deficits improved postoperatively. This indicates that surgery in ISCH should not be delayed in symptomatic patients.

Thoracic ventral spinal cord herniation with progressive myelopathy - A case report and review of the literature

Background

Idiopathic spinal cord herniation (ISCH) is a rare, underrecognized, and often misdiagnosed entity of unclear pathogenesis that typically presents as a slowly progressive thoracic myelopathy. There are less than 200 such cases reported in the literature. ISCH diagnosis and treatment are often delayed contributing to greater fixed neurological deficits, often leading to costly, unnecessary imaging studies, and inappropriate surgery.

Case Description

Here, a 48-year-old female presented with trauma-induced ISCH characterized by gradually worsening lower extremity myelopathy.

Conclusion

Idiopathic spinal cord herniation (ISCH) is rare, often underdiagnosed posttraumatic myelopathy that, when accurately diagnosed and treated, can result in good outcomes.

Comparison of Anterior and Posterior Surgical Approaches for Treatment of Thoracic Myelopathy

OBJECTIVE

To study a large multi-institutional sample of patients undergoing anterior versus posterior approaches for surgical decompression of thoracic myelopathy.

METHODS

The American College of Surgeons National Surgical Quality Improvement Program was queried for patients who underwent decompression for thoracic myelopathy between 2007 and 2015 via anterior or posterior approaches. Patients were excluded if they were undergoing surgery for tumors to isolate a degenerative cohort. Demographics, patient comorbidities, operative details, and postoperative complications were compared between the 2 cohorts.

RESULTS

Although there were no differences in age (P = 0.06), sex (P = 0.72), or American Society of Anesthesiologists class (P = 0.59), there were higher rates of steroid use (P = 0.01) and hematologic disorders that predispose to bleeding (P = 0.04) at baseline in the posterior approach cohort. The posterior approach patients had longer operative times (P = 0.03), but there were no differences in length of stay (P = 0.64). Although there were no significant differences in the rates of major organ system complications or return to the operating room (P = 0.52), the posterior approach cohort displayed a trend toward increased severe adverse complications (29.8% vs. 17.6%, P = 0.28) compared with the anterior approach cohort.

CONCLUSION

Although the anterior approach to surgical decompression of thoracic myelopathy demonstrated a lower complication rate, this result did not reach statistical significance. The anterior approach was associated with significantly shorter mean operative time, but otherwise there were no significant differences in operative or postoperative outcomes. These findings may support the favorability of the anterior approach but warrant further investigation in a larger study.

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.

Ventral Longitudinal Intraspinal Fluid Collection in Patients with Cervical Disc Herniation: A Report of Two Cases

We encountered two cases of cervical disc herniation, wherein cerebrospinal fluid collection in the ventral epidural space between the cervical spine and the thoracic spine was noted. The patients, two women aged 71 and 43 years, were diagnosed with cervical disc herniation and underwent anterior cervical discectomy and fusion. Unexpected cerebrospinal fluid leakage was observed prior to exposure of the dura mater. Notably, the dura mater was intact following the removal of the herniated disc in both cases. No cerebrospinal fluid leakage symptoms were observed, and relief from the neurological symptoms related to the cervical disc herniation was observed in both cases following the surgery. Findings of preoperative magnetic resonance imaging and computed tomography myelography were carefully reviewed, retrospectively. Both patients presented with similar features including expansion of cerebrospinal fluid collection in the ventral epidural space between the cervical spine and the thoracic spine. These observed features were similar to those of superficial siderosis, which is a form of duropathy—a disease caused by dural defects. Therefore, the patients in this case study might have a subclinical duropathy with associated cervical disc herniation.

Radiological data of brachial plexus avulsion injury associated spinal cord herniation (BPAI-SCH) and comparison to anterior thoracic spinal cord herniation (ATSCH)

Spinal cord herniation (SCH) is a rare cause of myelopathy. When reported, SCH has most commonly been described as occurring spontaneously in the thoracic spine, and being idiopathic in nature (anterior thoracic spinal cord herniation, ATSCH) [1–3]. Several theories have been proposed to explain its occurrence, including congenital, inflammatory, and traumatic etiologies alike [1–4]. Even more rarely, SCH has been described to occur in the cervical spine in association with brachial plexus avulsion injuries (BPAI-SCH). In our accompanying article, “Late Cervical Spinal Cord Herniation Resulting from Post-Traumatic Brachial Plexus Avulsion Injury,” two cases of BPAI-SCH are presented and discussed in the context of the reviewed literature [5]. Here, pertinent accompanying follow-up data was collected and is presented for the cases, including postoperative radiographic outcome imaging. Furthermore, a table is presented comparing and contrasting ATSCH to BPAI-SCH. Although the two phenomena have been previously grouped together, this table highlights ATSCH and BPAI-SCH as distinct entities; more specifically, BPAI-SCH is a separate, long-term complicating feature of BPAI. This supplementary data helps treating physicians by increasing awareness and knowledge of BPAI-SCH as a distinct entity from ATSCH and cause of delayed neurological deterioration.

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Myelopathy due to spinal cord herniation (SCH) is rare.

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Brachial plexus avulsion injury associated SCH (BPAI-SCH) is a unique type of SCH.

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Follow-up data for a case of BPAI-SCH treatment is presented.

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BPAI-SCH is compared and contrasted with more common SCH subtypes.

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BPAI-SCH recognition and treatment is essential for patient improvement.

Surgical Management of Idiopathic Thoracic Spinal Cord Herniation

BACKGROUND

Idiopathic spinal cord herniation is a rare condition that involves spinal cord herniation through a defect in the ventral dura.

CASE DESCRIPTION

We present a case of a 61-year-old woman who initially presented in 2016 with an approximately 1-year history of burning right lower extremity pain and gait instability. Her neurologic examination was consistent with thoracic Brown-Sequard syndrome, and spinal magnetic resonance imaging showed a focal defect in the ventral dura at the superior aspect of T4 with the left aspect of the cord herniating into the defect. In 2018, she underwent a T3-T4 laminectomy with T3 pedicle take down and medial facetectomy, with reduction of the herniated cord.

CONCLUSIONS

Idiopathic spinal cord herniation is an uncommon spinal cord disorder with a paucity of data reported. Our case report of a classic case of idiopathic spinal cord herniation presenting as Brown-Sequard syndrome and managed surgically will contribute to the data in this field.

Understanding Idiopathic Spinal Cord Herniation - A Comprehensive Review of Imaging and Literature

Idiopathic spinal cord herniation (ISCH) is displacement of spinal cord through a dural or arachnoidal defect. Most patients present with back pain or myelopathy, paresthesia, and sensory or motor weakness. Imaging findings include anterior displacement of the cord with possible kink, no filling defect on CT myelography, and no restricted diffusion/mass lesion on magnetic resonance imaging. Abrupt kink in the spinal cord or widened cerebrospinal fluid (CSF) space can be caused by a variety of reasons. The differential considerations include arachnoid web, intradural extramedullary epidermoid or arachnoid cyst, abscess or cystic schwannoma. We discuss the features, imaging, differentials, and treatment of ISCH as a rare cause of such kink in the cord. While reading such cases, a radiologist should include the location, segments involved, cord signal abnormality, visible defect, scalpel sign or C–sign, ventral cord kink, nuclear trail sign, the ventral CSF space preservation, or obliteration and the type.

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.

Factors Affecting the Severity of Neurological Disorders in Thoracic Idiopathic Spinal Cord Herniation

STUDY DESIGN

Retrospective multicenter case-controlled study.

OBJECTIVE

The objective of this study was to quantitatively examine imaging findings of idiopathic spinal cord herniation (ISCH) and determine the relationship between the image findings and the severity of pre- and postoperative neurological symptoms.

SUMMARY OF BACKGROUND DATA

Many radiographic types of ISCH have been identified with regard to the location of the hernial opening or amount of herniated spinal cord. However, few previous studies have investigated the relationship between radiographic findings and the severity of neurological symptoms.

METHODS

Of 30,469 patients who underwent spinal surgery at 7 hospitals, 18 patients who underwent surgery for ISCH were identified. Their preoperative neurological severity, disease duration, magnetic resonance imaging findings, computed tomography myelography findings, surgical findings, and postoperative improvements were retrospectively examined. The spinal cord kink angle and minimum cord occupancy rate within the dural tube were measured. In addition, herniation was classified according to the location of the hiatus as either central (type C) or lateral (type L) type.

RESULTS

A negative correlation was found between the spinal cord kink angle and the minimum cord occupancy rate. Patient age was significantly higher in the severe paralysis group than in the mild paralysis group. In addition, the number of patients with type C herniation and the kink angle were significantly higher in the severe paralysis group. The number of patients with type L herniation was higher in the significant recovery group than in the mild recovery group; however, the difference was not significant.

CONCLUSION

Patients with a large spinal cord kink angle had a smaller spinal cord occupancy rate within the dural tube, and this resulted in severe preoperative conditions. Type C ISCH cases had a severe preoperative neurological deficit and poor postoperative neurological recovery, and the spinal cord in such cases might be damaged irreversibly.

LEVEL OF EVIDENCE

4.

Idiopathic thoracic transdural intravertebral spinal cord herniation

Idiopathic spinal cord herniation is a rare and often missed cause of thoracic myelopathy. The clinical presentation and radiological appearance is inconsistent and commonly confused with a dorsal arachnoid cyst and often is a misdiagnosed entity. While ventral spinal cord herniation through a dural defect has been previously described, intravertebral herniation is a distinct entity and extremely rare. We present the case of a 70-year old man with idiopathic thoracic transdural intravertebral spinal cord herniation and discuss the clinico-radiological presentation, pathophysiology and operative management along with a review the literature of this unusual entity.

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.

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.

Spinal Intradural Arachnoid Webs Causing Spinal Cord Compression with Inconclusive Preoperative Imaging: A Report of 3 Cases and a Review of the Literature

OBJECTIVE

Spinal arachnoid webs are a rare variant of spinal arachnoid cysts where 1 or multiple focal membranes of arachnoid tissue obstruct the subarachnoid space. Only 11 prior cases of arachnoid webs have been reported in the literature. We present a series of 3 consecutive cases of arachnoid webs from our institution and review the literature on this rare condition to provide recommendations for its management.

METHODS

Retrospective chart review was performed for 3 consecutive cases of intradural arachnoid webs causing spinal cord compression at our institution, with inconclusive preoperative imaging, treatment with surgical decompression, and resection. There were no external sources of funding.

RESULTS

Our cases occurred dorsally in the thoracic spine and were associated with syringomyelia. Preoperative magnetic resonance imaging, computed tomography myelography, and cine magnetic resonance imaging were inconclusive, and the definitive diagnosis was made with intraoperative ultrasound. Patients underwent laminectomies and resection of arachnoid webs. Unique from prior reports of arachnoid webs, the webs in the present cases were composed of multiple septated longitudinal membranes rather than a transverse band. All patients had improvement of presenting symptoms postoperatively.

CONCLUSIONS

Intradural arachnoid webs causing spinal cord compression are rare. Preoperative imaging may be inconclusive. Because of the septated longitudinal nature of the visualized membranes, we propose a 1-way valve mechanism of cerebrospinal fluid obstruction causing gradual cord compression and resultant syringomyelia.

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

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

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.

The thoracic anterior spinal cord adhesion syndrome

OBJECTIVES

This study included a series of middle-aged male and female patients who presented with chronic anterior hemicord dysfunction progressing to paraplegia. Imaging of anterior thoracic cord displacement by either a dural adhesion or a dural defect with associated cord herniation is presented.

METHODS

This is a retrospective review of cases referred to a tertiary neuroscience centre over a 19-year period. Imaging series were classified by two experienced neuroradiologists against several criteria and correlated with clinical examination and/or findings at surgery.

RESULTS

16 cases were available for full review. Nine were considered to represent adhesions (four confirmed surgically) and four to represent true herniation (three confirmed surgically). In the three remaining cases the diagnosis was radiologically uncertain.

CONCLUSION

The authors propose "thoracic anterior spinal cord adhesion syndrome" as a novel term to describe this patient cohort and suggest appropriate clinicoradiological features for diagnosis. Several possible aetiologies are also suggested, with disc rupture and inflammation followed by disc resorption and dural pocket formation being a possible mechanism predisposing to herniation at the extreme end of a clinicopathological spectrum.

Spinal arachnoid cysts in the pediatric population: report of 31 cases and a review of the literature

OBJECT

The goal of this study was to review all cases of pediatric spinal arachnoid cysts (SACs) surgically treated at the authors' institution between 1992 and 2008 and to compare these cases to the published literature for the general population.

METHODS

The charts of all pediatric patients with SACs were reviewed for demographics, medical history, presenting symptoms, imaging findings, operative procedure(s), complications, and outcomes. Following a complete literature review, the pediatric data were compared with data from the general population and unique findings associated with pediatric patients were identified.

RESULTS

Thirty-one pediatric patients (median age 6.9 years) underwent operative intervention for SACs between 1992 and 2008 (median duration of follow-up 4.2 years). There were 17 female patients (55%) and 14 male patients (45%). Twenty-one patients (68%) presented with symptoms of radiculopathy or myelopathy. The most common presenting symptoms were pain (42%), lower-extremity weakness (39%), gait instability (32%), spasticity (19%), sensory loss (10%), and bladder dysfunction (7%). In 3 patients (10%) SACs were incidental findings. Intradural SACs were more common (18 patients, 58%) than extradural SACs (11 patients, 36%). One patient (3%) had extradural and intradural components. One patient (3%) had a purely intramedullary cyst, and 1 patient (3%) had both an intradural and intramedullary component. Of the 18 intradural SACs, 9 (50%) were located ventral to the spinal cord and 9 (50%) were dorsally situated. One dorsal intradural SAC had an intramedullary component. All extradural SACs were located dorsal to the spinal cord. Intradural SACs were primarily concentrated in the cervical and thoracic regions (67%), whereas extradural cysts were more evenly distributed between the thoracic, lumbar, and sacral regions. Of the 18 patients with intradural SACs, 13 (72%) had significant previous CNS abnormalities, compared with 3 (27%) of 11 patients with extradural SACs. There were 2 operative complications. One patient had a CSF leak treated with a lumbar drain, and the second patient had a pseudomeningocele. No patients had neurological deterioration as a result of surgical intervention. Twenty-one patients (68%) had complete remission of symptoms, 6 (19%) had improvement, 3 (10%) were stable, and 1 (3%) has worsening of symptoms with recurrence that ultimately required cystoperitoneal shunting, despite multiple failed attempts at fenestration.

CONCLUSIONS

Spinal arachnoid cysts are rare lesions in the pediatric population. Affected patients present with back pain, weakness, and/or gait instability. In children, SACs predominantly develop in the thoracic region and are more likely to occur intradurally, compared with SACs in the general population. Overall outcomes following surgical fenestration or excision of SACs are excellent, with complete remission or improvement of symptoms achieved in 87% of cases.

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.

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.

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.

MRI findings in herniation of the spinal cord

Herniation of the spinal cord is a rare condition that causes non specific neurological deficits that are often a diagnostic challenge to clinicians. Despite several reports in the neurosurgical literature, it is only recently that the imaging appearances of this condition have come to be recognised, due mainly to the widespread adoption of spinal MRI. It is important for radiologists to recognise the telltale MRI features of this condition, as several cases have undergone initial misdiagnosis, resulting in delayed treatment We present a case with typical imaging features to familiarise radiologists with this condition, as it is likely that more cases will come to the fore, with more spinal MRIs being performed.

Spinal meningocele due to iatrogenic dural puncture during epidural analgesia for childbirth: 5-year history of headache with a spinal etiology

Patients undergoing epidural injection for labor pains occasionally sustain iatrogenic inadvertent puncture of the dura with or without damage to the underlying neurological structures. This may be associated with CSF leakage, headache, neurological deficit, and infection. Rarely, the headache persists for years. To the authors' knowledge, chronic headache due to acquired spinal meningocele featuring as a duplicated dural sac, as a sequela of traumatic inadvertent dural puncture, has not been previously reported.

The authors report a case of a 20-year-old woman with persistent headaches following an epidural injection. Five years later, the persistent headache was found to be due to a large acquired spinal meningocele. The operative removal of the meningocele led to resolution of headaches.

This report highlights the importance of considering a spinal condition as a culprit for chronic headache and postulates a mechanism for the formation of the acquired spinal meningocele appearing as a duplicated dural sac. The authors recommend early MR imaging of the spine for any persisting headache that has a history of attempted spinal access. If an acquired spinal meningocele collection is found, exploration with a view to complete removal of the sac should be considered.

To the authors' knowledge, this is the first case report depicting a rare, treatable cause of chronic spinal hypotension resulting in headaches.

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.

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.