INTRADURAL HERNIATION OF LUMBAR INTERVERTEBRAL DISCS

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.

Intradural free fragment of the lumbar region: report of two cases

Two cases of intrathecal disc protrusion and a review of the literature is presented. The rarity of this complication, which might occur after an incomplete disc removal, is pointed out. These two cases confirmed that the L4-5 interspace is the one most commonly affected.

Intradural rupture of lumbar intervertebral disc

Two cases of intradural disc rupture with cauda equina compression are reported. Myelography demonstrated complete block and at surgery intradural fragments of sequestrated disc material were found. The pathogenesis of this condition is reviewed and our recommendation for management is presented.

Intradural herniated cervical disc. Case report

✓ An unusual case is presented in which a fragment of cervical disc was found within the dura. The literature has been reviewed and only two similar cases, which are described, have been found. The pathogenic factors of the lesion are discussed.

Intradural disc rupture. Report of two cases

Two cases of intradural disc rupture are presented, and 43 cases found in the literature are reviewed. Dandy's original observations concerning this lesion correlate well with contemporary experience. Characteristics of the history and physical findings are uniform enough to suggest a clinically identifiable syndrome. Microscopic examination of the Cytospin cerebrospinal fluid specimen and the use of computerized tomography with metrizamide may suggest the diagnosis preoperatively. Despite significant neurological deficit associated with lumbar lesions, the prognosis following surgery is good.