Intradural rupture of lumbar intervertebral disc

Magnetic resonance imaging features of canine intradural/extramedullary intervertebral disc extrusion in seven cases

Intervertebral disc disease, including intervertebral disc extrusions and protrusions, is the most common spinal cord disorder in dogs. Atypical and uncommon intervertebral disc herniations include intradural/intramedullary disc extrusion, intervertebral foraminal disc extrusion and intervertebral disc herniation (Schmorl's node). Intradural/extramedullary disc extrusion is the least common type of intervertebral disc herniation in veterinary medicine, characterized by extruded disc material within the intradural space. To date, only one study has been published in veterinary medicine reporting intradural/extramedullary disc extrusions. In this study, low field MRI was used, and the authors could not find any MRI features to diagnose with confidence an intradural/extramedullary disc location of the extruded disc material. The aim of this study was to describe the high field (1.5T) MRI characteristics of surgically confirmed intradural/extramedullary disc extrusions. This is a retrospective, multicentric and descriptive study. Inclusion criteria was surgical confirmation of intradural/extramedullary disc extrusion by durotomy and complete MRI study of the spine. Seven cases were included. Images were reviewed by a radiology resident and a certified radiologist, with emphasis on the following signs: “Golf-tee sign” (widening of the subarachnoid space cranial and caudal to the lesion), “Beak sign” (pointed and sharp compressive lesion) and “Y sign” (division of the dura and arachnoid layers). MRI showed a “Y sign” in all the cases (7/7) seen from the T2-weighted sagittal views, while “Golf-tee sign” was not recognized in any of the cases (0/7). Additionally, “beak sign” was present in half of the cases (4/7). “Y sign” maybe a reliable MRI feature for identifying intradural/medullary disc extrusions from the MRI study. As the arachnoid is peeled from the dura by the disc herniation there is a splitting of the arachnoid mater and the ventral dura. The intradural disc material will be surrounded by CSF signal intensity margin, giving the appearance of a Y, which can be identified from the T2-weighted sagittal images.

Intradural Disc Herniation in the Setting of Congenital Lumbar Spinal Stenosis

INTRODUCTION

Accounting for an estimated 1.10-1.76% of all lumbar herniations, lumbar intradural disc herniation (IDH) occurs primarily in males during the fourth to fifth decades of life. While not validated, congenital lumbar spinal stenosis (CLSS) is implicated as one precipitating factor for IDH.

CASE REPORT

We report 28-year-old Hispanic female with CLSS, severe obesity, and degenerative disk disease, with a history of minimally invasive surgical (MIS) decompression for a large paracentral L4-5 disc herniation at 25. After three years, the patient developed sudden burning dysesthesias in the L4-5 dermatomes bilaterally and temporary leg weakness. Lumbar magnetic resonance imaging exhibited severe L4-5 spinal stenosis, and the patient underwent repeat MIS decompression, which again provided her with adequate symptom resolution. However, 20 days postoperatively she developed cauda equina syndrome with anal dysfunction, and bilateral leg and foot weakness. Upon open surgical exploration we discovered a tense L4-5 dural protrusion. After a dorsal durotomy, a large IDH with a ventral dural tear was identified. Subsequent to adequate debulking of the IDH, the ventral tear was repaired, and an expansile duraplasty was performed. Overall, the patient's bladder and bowel function, pain, hypoesthesia, and motor strength all improved. Two weeks after surgery she presented with a lumbar pseudomeningocele that was managed conservatively.

CONCLUSION

This report not only highlights an atypical presentation of IDH and is the first case of CLSS linked with IDH, lending support to the hypothesis that CLSS can lead to IDH, but also provides a comprehensive review of IDHs.

Intradural Lumbar Disc Herniation: A Case Report and Literature Review

Background

Lumbar disc herniation into the dural space is a very rare phenomenon of degenerative lumbar lesions in the elderly population, and its potential pathogenesis and natural course remain unclear.

Case description

We describe a rare case of intradural lumbar disc herniation. A 68-year-old man presented with progressive lower back pain and radiating pain and numbness in both legs for 3 years. Magnetic resonance imaging revealed a large herniated disc at L4-L5. Posterior discectomy and fusion of the L4-L5 was performed after conservative treatment failed. Intraoperatively, only minimal disc fragments in the epidural space were found after meticulous probing following laminectomy of the L4-L5 vertebrae. The dorsal dura mater was saturated, tense, and bulged at the L4-L5 levels; additionally, an intradural mass was palpable and confirmed by intraoperative ultrasonography. Subsequently, dorsal middle durotomy was performed. Upon opening the dural sac, a large cauliflower-like mass similar to nucleus pulposus tissue was found near the arachnoid membrane. The mass was dissociative and could be completely resected. The dorsal dural incisions were closed after careful exploration, followed by fixation and fusion of the L4-L5 levels. Pathological examination revealed disc tissue with central balloon-type cystic degenerative changes. The patient’s lower back pain and radiating pain and numbness of both legs improved remarkably postoperatively, and he became asymptomatic at 3 months postoperatively.

Conclusion

Intradural lumbar disc herniation should be highly suspected when intraoperative findings are incompatible with findings from the preoperative imaging examination, and it could be further confirmed via intraoperative ultrasonography and pathological examination of the resected tissue from the dural space. Prompt surgery is recommended, and surgical results are usually favorable. We also reviewed the literature and discussed the potential pathogenesis, natural course, diagnosis, and treatment of intradural lumbar disc herniation.

Intradural disc herniation with cranial migration of an excluded fragment

Intradural herniation is a rare complication of the intervertebral disc disease. The history and present clinical findings may suggest the diagnosis. Although the myelographic signs are well known, intradural hernias have seldom been illustrated by magnetic resonance imaging (MRI). We present the case of an intradural disc hernia with cranial migration of a sequestrated fragment illustrated by both myelography and MRI. To our knowledge, such a case has never been reported in the literature so far.

Intradural lumbar disc herniations: the role of MRI in preoperative diagnosis and review of the literature

The goal of this article is to report our experience on intradural lumbar disc herniation, consider the causes of this pathology, and analyze it from clinical, diagnostic, and therapeutic perspectives with a particular emphasis on the role of MRI in preoperative diagnosis. We analyzed nine patients treated surgically for intradural lumbar disc hernia. All of them underwent surgery, and hemilaminectomy was performed. In six cases, the diagnosis of intradural herniation was definitive and, in the three remaining, it was confirmed at surgery. In five cases, CT (with no contrast medium) of the lumbar area revealed disc herniation, but none could it confirm its intradural location. Myelography was performed in two cases but also could not prove intradural extrusion. Magnetic resonance imaging study was used in four cases. In five, the postoperative outcome has been excellent. Patients 6 and 9 recovered anal function postoperatively; patient 6 suffered from occasional and mild micturition urgency. The three patients previously operated (1, 2, 7) showed good outcome. Presently, we believe that radiologic diagnosis of intradural herniation is possible in carefully selected patients, thanks to MRI with gadolinium.

Intraradicular and intradural lumbar disc herniation: experiences with nine cases

BACKGROUND

Intraradicular or intradural disc herniation is a very rare complication of spinal degenerative processes. The aim of our study is to analyze the clinical spectrum, the mechanism, and the treatment of this acute spinal pathology.

METHODS

Retrospective clinical examination was performed in nine personal cases of intradural disc herniation: among these, six were associated with lateral perforation, the remaining three with intradural herniation and ventral perforation. A review of the literature concerning mainly the frequency pathogenesis and diagnosis of intradural disc herniation has also been done.

RESULTS

Nine cases of intradural herniations comprise 1.51% of the 593 cases of ruptured lumbar disc that underwent surgery from 1980 to 1992. The site most frequently involved is at level L4-L5, and 30% of patients have previously undergone surgery for lumbar disc herniation. Most patients reported in literature and in our present series have been complaining of a chronic history of sciatica, complicated later by bilateral neurologic signs. In the present series, diagnosis was obtained by means of myelography and computerized tomography; magnetic resonance imaging was performed in one case. All patients underwent surgery, reporting excellent results in five cases and good results in the other four. Surgery was performed either with an interlaminar approach or with a bilateral laminectomy in cases of ventral perforation.

CONCLUSIONS

There is no typical neuroradiologic picture of intraradicular herniation, while a total or subtotal block is frequently observed in intradural ventral perforations. Dural perforation is often an unexpected intraoperative finding. Surgical treatment is always necessary. Favorable results are obtained if surgical treatment is carried out before the neurologic deficit becomes too pronounced.

Intradural disc herniations pathogenesis, clinical picture, diagnosis and treatment

The relatively rare occurrence and uncertainty about pathogenesis of intradurally displaced disc herniations stimulated an anatomico-pathological study into intradural disc herniations. The relation between the ventral dura and posterior longitudinal ligament in the cervical, thoracic, lumbar and sacral regions were examined macroscopically and microscopically, and ventral and dorsal dural thickness was compared in 20 adult autopsies on patients who died from various causes; in addition, 20 late abortions and newborn cadavers were investigated in the same way. In this study, a total of 40 autopsies has shown that the ventral dura is most frequently and firmly attached to the posterior longitudinal ligament at the L4-L5 level and these adhesions may be congenital. In the adult cadavers dorsal dura was found to be thicker than the ventral dura in the lumbar and lower cervical interspaces. Three personal clinical cases of intradurally herniated disc prolapse are shortly described and the diagnosis and management of this pathology discussed.

Intradural lumbar disc protrusion. A case report

We report a rare case of intradural lumbar disc protrusion describing a specific myelographic appearance that may help in preoperative diagnosis. Most of these patients present with acute sciatica and neurologic deficit. Preoperative awareness and diagnosis is of importance because the extruded disc protrusion lies intrathecally and must be specifically looked for and removed from its intradural position.