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

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

Background

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

Methods

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

Results

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

Conclusions

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

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

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

Case report: A vertebral bone spur as an etiology for spinal cord herniation: case presentation, surgical technique, and review of the literature

Objective

The pathophysiology of idiopathic spinal cord herniation remains unknown. However, several different factors have been postulated, such as congenital causes (ventral dura mater duplication, preexisting pseudomeningocele, or other congenital dural defects), inflammation, remote spinal trauma, or thoracic disc herniation. Herein, the diagnosis and surgical treatment of a patient with spinal cord herniation caused by an intraspinal bone spur is presented along with a relevant literature review.

Case presentation

A 56-year-old male patient presented with a non-traumatic Brown-Sequard syndrome persisting for over 1 year. A magnetic resonance imaging of the spinal axis revealed a ventral spinal cord displacement in the level of T 6/7. A supplementary thin-sliced computed tomography of the spine revealed a bone spur at the same level. For neurosurgical intervention, T 6 and T 7 laminectomy was performed. The cranial and caudal end of the right paramedian ventral dural defect was visualized and enlarged. Following extradural spinal cord mobilization by denticulate ligament transection, the spinal cord was finally released. The spinal cord was rotated and the ventral closure of the dural defect was performed by continuous suture. The patient recovered from surgery without additional deficits. The patient's postoperative gait, sensory, and motor function deficits improved, and further neurological deterioration was prevented.

Conclusion

Since the first description of spinal cord herniation by Wortzman et al. in 1974, approximately 260 cases have been reported in the literature. In addition to other causes, intraspinal bone spur is a possible cause of spinal 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.

Scalpel sign: Dorsal thoracic arachnoid web, thoracic arachnoid cyst and ventral cord herniation

The “Scalpel sign” is a radiological sign which can be identified on magnetic resonance imaging and indicates dorsal compression of the spinal cord [1]. Prior descriptions of a “Scalpel sign” have been reported in the literature and the awareness and identification of this pathognomonic sign may aid in the rapid diagnosis and treatment of patients with dorsal arachnoid web, dorsal arachnoid cyst or ventral cord herniation. We describe 3 cases which highlight these rare conditions for which this sign is pathognomonic and summarize the pertinent literature related to these disorders [1,2].

Atypical radiographic case of arachnoid web without scalpel sign

Background:

Spinal arachnoid webs (SAW) occur when abnormally thickened bands of arachnoid membranes commonly located dorsal to the thoracic spine cause blockage of normal cerebrospinal fluid (CSF) flow, resulting in focal cord compression and myelopathy. The pathognomonic MR finding for SAW is the “positive scalpel sign” comprised of an enlarged dorsal CSF space with a normal ventral subarachnoid space. The main differential diagnostic consideration for SAW is idiopathic spinal cord herniation (ISCH); however, for ISCH, MR studies classically demonstrate ventral displacement of the spinal cord through an anterior dural defect. Here, we describe a 60-year-old female with an atypical SAW at the T3-T4 level (i.e., the preoperative MR failed to demonstrate the “positive scalpel sign”). Nevertheless, at surgery, intraoperative ultrasonography confirmed that SAW was present and was decompressed/marsupialized/removed.

Case Description:

A 60-year-old female presented with sensory impairment to both lower extremities. The thoracic MR images showed an enlarged dorsal CSF space at the T3-T4 level but without the “scalpel sign” suggesting “interruption” of CSF flow by thickened bands of focal dorsal arachnoidal tissues. Although the initial preoperative diagnosis was ISCH, intraoperative ultrasound (IOUS) confirmed the presence of a thickened arachnoid band, confirming the diagnosis of a SAW that was appropriately decompressed/resected.

Conclusion:

Correctly, establishing the preoperative diagnosis of a SAW based on MR imaging may sometimes be difficult as the typical “scalpel sign” may not be present in all patients. Notably, in cases like this one, IOUS may critically confirm the diagnosis of SAW thus leading to appropriate SAW decompression/removal.

Transdural spinal cord herniation: A rare cause of neurologic impairment: Report of two cases and review of the literature

Introduction

Herniation of the thoracic spinal cord is a rare pathology related to the genesis of a breach in the anterior dura. Adding to the previously published cases, we report our department's experience with 2 cases of young adults who presented with transdural spinal cord herniation following spinal trauma.

Presentation of the cases

We report the cases of 2 men aged 27 and 57, with history of spinal trauma, who presented diverse clinical complaints (motor impairment, genito-sphincteric disorders, etc.). Spinal cord MRI showed an anterior displacement of the spinal cord. Both patients were operated. Peroperative findings and radiological features were concordant with transdural spinal cord herniation.

Discussion

Spinal cord herniation is a rare condition which is usually related to a misdiagnosed spinal trauma. Pathogenesis is still being debated. This condition may lead to a myelopathy potentially responsible for severe neurologic impairment, mainly presenting as a Brown-Sequard syndrome. Diagnosis is based on clinical and radiologic features on MRI. Surgical treatment is proposed when neurological signs are found. Long-term clinical and radiological monitoring is necessary for paucisymptomatic, non-operated patients.

Conclusions

Based on the described cases, we tried to review the main clinical, radiological and therapeutic features related to this condition.

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Herniation of the thoracic spinal cord is due to a breach in the anterior dura of an uncertain pathogenesis

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Transdural spinal cord herniation is a little known cause for myelopathy potentially responsible for severe neurologic impairment

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Main clinical features are related to a Brown-Sequard syndrome

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In symptomatic cases, surgical treatment may stabilize or even improve neurologic impairment

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.

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.

Clinico-radiological correlation and surgical outcome of idiopathic spinal cord herniation: A single centre retrospective case series

Context: Idiopathic spinal cord herniation (ISCH) remains an obscure, under recognised but potentially treatable entity among the etiologies of compressive myelopathy.Findings: Here, we present a retrospective case series of eight patients of ISCH with their clinical features, imaging findings and long-term follow up data along with a relevant review of the literature. Mean age at presentation was 36 years with the duration of symptoms ranging from two months to more than thirty years. Contrary to existing data, only two patients in our series had the classical presentation of Brown-Sequard syndrome (n = 2). The clinical spectrum of the presentation was broad with pure spastic quadriparesis (n = 3), girdle sensation (n = 1) and radiculopathy (n = 1), the latter presentation has been unreported for ISCH. The typical radiological picture was seen in all patients. All except one patient was managed conservatively. In the one patient who underwent bilateral dentate ligament excision, there was mild functional improvement on long-term follow-up despite a definite worsening of the radiological picture. Five of the patients had a long-term follow-up with no clinically or functionally significant worsening.Clinical relevance: The current study highlights the wide clinical spectrum and relatively stable natural course of ISCH and reports on hitherto undescribed presentation as radiculopathy.

Spondylotic and Other Structural Myelopathies

PURPOSE OF REVIEW

This article highlights both common structural causes of myelopathy, such as spondylotic disease, and infrequent but treatable causes, such as syringomyelia, spinal cord herniation, arachnoid cyst, arachnoid band and web, epidural lipomatosis, Hirayama disease, and arachnoiditis.

RECENT FINDINGS

Neuroimaging improvements and availability have uncovered many structural abnormalities in the spines and spinal cords of patients who were asymptomatic or minimally symptomatic. Recent published clinical series have improved our knowledge of the natural history of structural abnormalities and the risks of intervention versus conservative management.

SUMMARY

Myelopathy from a suspected structural cause is a common reason for neurologic consultation. Correlation between the history, examination, and imaging are especially important to determine whether intervention is necessary or conservative management is the best option.

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.

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.

Rare dorsal thoracic arachnoid web mimics spinal cord herniation on imaging

Background:

Dorsal arachnoid webs (DAWs) are rare clinical entities that can mimic other conditions on magnetic resonance imaging (MRI). Here, we present a case of DAW that was misdiagnosed on MR as a ventral cord herniation.

Case Description:

A 35-year-old female presented with a 1-year history of lower extremity weakness and numbness. The MRI of the thoracic spine showed ventral cord displacement with syringomyelia. The computed tomography myelogram demonstrated ventral cord herniation. Intraoperatively, the patient had a dorsal thoracic web in the absence of cord herniation. Within 8 postoperative weeks, the patient had improved, and the follow-up MI showed a significant reduction in the syrinx size.

Conclusion:

On MR scans, DAWs may look like ventral cord herniation. However, the positive “scalpel sign” and syrinx, the absence of an arachnoid cyst on myelography, and the findings on cine MR help differentiate DAWs from ventral cord 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.

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.

Conventional and Advanced Imaging of Spine Oncologic Disease, Nonoperative Post-treatment Effects, and Unique Spinal Conditions

In this review, we discuss the imaging features of diseases and conditions ranging from neoplastic to nonoperative post-treatment effects to unique conditions of the spine. Additionally, advanced imaging may increase diagnostic certainty in cases where conventional imaging characteristics of benign lesions and malignant pathology are variable.

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.

Clinical and Radiographical Differences Between Thoracic Idiopathic Spinal Cord Herniation and Spinal Arachnoid Cyst

STUDY DESIGN

A retrospective, multicenter, case-controlled study.

OBJECTIVE

The aim of this study was to investigate the clinical and radiographical differences between thoracic idiopathic spinal cord herniation (ISCH) and spinal arachnoid cyst (SAC).

SUMMARY OF BACKGROUND DATA

ISCH and SAC are relatively rare diseases. Preoperative misdiagnose was frequently reported in both; however, these clinical and radiographical differences remain unclear.

METHODS

Of 30,469 patients who underwent spinal surgery, 18 (0.059%) and 22 (0.072%) patients were diagnosed as ISCH or SAC at nine hospitals, respectively, and their clinical and radiographical data were retrospectively evaluated. The spinal cord kink angle was measured on magnetic resonance or computed tomography myelography sagittal images; the kink angle was the exterior angle formed between the two tangents to the dorsal-side inflection points at the maximally affected level.

RESULTS

There were no significant differences in age, gender, and duration of symptoms. Preoperative motor deficit was significantly higher (94.4%) and severer (manual muscle testing: 3.1 ± 1.1) in ISCH. Brown-Séquard syndrome was observed in 38.9% of ISCH, while no patients in SAC. In addition, leg sensory disorder and bladder rectal disorder were significantly more common in ISCH, while back pain was significantly frequent in SAC. With respect to radiographical findings, the length of disease (5.1 ± 2.7 levels) and altered cerebrospinal flow (CSF) (81.8%) in the lesion was significantly longer and more common in SAC. On the contrary, the kink angle was significantly greater in ISCH (54.0 ± 23.1°) than in SAC (14.1 ± 12.0°) (P < 0.001). The cut-off value of the kink angle to distinguish ISCH and SAC was 32.8°.

CONCLUSION

Patients with ISCH commonly had severe preoperative neurological deficit, Brown-Séquard syndrome, and higher kink angle, while patients with SAC had back pain, longer length of disease, and altered CSF in the lesion.

LEVEL OF EVIDENCE

4.

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

INTRODUCTION

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

CASE REPORT

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

CONCLUSION

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

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

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

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

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

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

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

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

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

Idiopathic Spinal Cord Herniation Presented as Brown-Sequard Syndrome : A Case Report and Surgical Outcome

Spinal cord herniation is a rare condition that has become increasingly recognised in the last few years. The authors report a case of idiopathic spinal cord herniation in a 33 year old woman performed with progressive Brown-Sequard syndrome. The diagnosis was made on MR imaging. After repairing the herniation, the patient made a gradual improvement. Potential causes are discussed, including a possible role of dural defect. In conclusion, idiopathic spinal cord herniation is a potentially treatable condition that should be more readily diagnosed that increasing awareness and improved imaging techniques.

Symptomatic thoracic spinal cord herniation: case series and technical report

BACKGROUND AND IMPORTANCE

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

CLINICAL PRESENTATION

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

CONCLUSION

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

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.