|Year : 2021 | Volume
| Issue : 1 | Page : 18-20
Intradural disc migration as a complication of chronic disc prolapse
Manoj Dayalal Singrakhia, I Ibad Sha
Department of Spine Surgery, Shanta Spine Institute, Nagpur, Maharashtra, India
|Date of Submission||28-Jul-2020|
|Date of Decision||25-Aug-2020|
|Date of Acceptance||17-Sep-2020|
|Date of Web Publication||18-May-2021|
Dr. I Ibad Sha
Fellow in Spine Surgery, Shanta Spine Hospital, Nagpur, Maharashtra
Source of Support: None, Conflict of Interest: None
Intradural migration of extruded disc is a rare phenomenon. The multiple anatomical barriers including annulus fibrosus, posterior longitudinal ligament, and dural sheath which limit migration of the intervertebral disc material are breached when this happens. It usually happens in case of disc prolapse of prolonged duration. We here report a rare case of dorsal intradural migration of an extruded disc fragment. The report is to emphasize the importance of proper preoperative evaluation and high clinical suspicion needed for preoperative diagnosis of this entity and to plan the treatment accordingly.
Keywords: Chronic disc prolapse, intradural disc migration, sequestrated disc herniation
|How to cite this article:|
Singrakhia MD, Sha I I. Intradural disc migration as a complication of chronic disc prolapse. Amrita J Med 2021;17:18-20
| Introduction|| |
Lumbar disc herniation is one of the major reasons for the surgical intervention of the spine. Among these, dorsal epidural migration of the lumbar disc extrusion is rare due to the anatomical limitation by posterior longitudinal ligament (PLL)., Rarely, this dorsally migrated disc if long standing may extend intradurally leaving a dural defect. We here report a rare case presenting with cauda equina syndrome in which a long-standing extruded disc has migrated dorsally and extending intradurally causing dural breach.
| Case Report|| |
A 52-year-old male patient presented to our hospital with sudden onset of weakness of the right lower limb along with difficulty in micturition and passing stools for 8 days. The patient was suffering from back pain with intermittent radiculopathy for 1 year. Clinical evaluation showed that the patient had motor deficit of S1 myotome on the right side, with the sensory impairment of S1, S2, S3, and S4 dermatomes. Ankle reflex was absent on the right side. The anal tone was reduced with decreased perianal sensation. The patient was clinically diagnosed as cauda equina syndrome and was started on intravenous steroids along with emergency radiological evaluation. Old magnetic resonance imaging (MRI) done 1 year back was available with the patient, which showed L5–S1 disc extrusion compressing the thecal sac and traversing nerve root [Figure 1].
|Figure 1: Magnetic resonance imaging sagittal (a,b) and axial (c,d) view at L5–S1 level taken 1 year back showing extruded disc|
Click here to view
Plain radiographs showed maintenance of normal lumbar lordosis with narrowing of L5–S1 disc space. MRI revealed a large extradural mass lesion at the L5–S1 disc level, which was predominantly hypointense on T1-weighted imaging (WI) and isointense on T2WI located dorsal to the thecal sac, significantly compressing the cauda equine [Figure 2]. On axial images, the epidural fat was completely obliterated, with a canal diameter measuring only <2 mm. Sagittal section revealed superior extension of the extruded disc material. The MRI was doubtful of intradural extension of the disc material. Classical clinical presentation with radiological features was suggestive of extruded disc; provisional diagnosis of extruded disc-induced cauda equina syndrome was made. Other less likely differentials of the tumor as well as dermoid was also kept in mind. Laboratory values, including erythrocyte sedimentation rate and C-reactive proteins, were within normal limits.
|Figure 2: Immediate preoperative magnetic resonance imaging sagittal (a, b) and axial (c,d) view at L5–S1 level showing extruded disc migrating superiorly|
Click here to view
The patient was posted for emergency operative decompression and posterolateral instrumented fusion. Intraoperatively, after L5 laminectomy, it was noted that the extruded disc located dorsally and laterally migrated on the left side with extension intradurally. It was also noted that the dura around the disc was thinned out at the site due to long-standing compression. Adhesions were noticed between the disc material and dural elements. The disc material was carefully removed without damaging the dura or the rootlets. Postremoval of the extruded disc, the dural tear was visualized [Figure 3]. The tear was sutured with No 5-0 silk along with fat patch and Surgicel coverage. The fascia was closed water tight and the positive pressure drain was used. Postoperatively, the patient was put on 2 days bed rest. Postdrain removal, there was no sign of cerebrospinal fluid leakage. One-month follow-up showed partial recovery of bowel and bladder function as well power of tendo Achilles.
|Figure 3: (a) Intraoperative picture showing the dural tear and extruded disc adjacent to it. (b) Extruded disc specimen after removal|
Click here to view
| Discussion|| |
Intradural disc herniation is where nucleus pulposus of the intervertebral disc displaces into the dural sac., It is a rare phenomenon with an incidence of only 0.30%. Disc herniation extending intradurally is less commonly seen because of natural barriers – dura, PLL, septum posticum, lateral peridural membrane of Fick, ligament of Hoffmann, and other contents of the epidural space (including nerve roots, fat, and Batson's epidural venous plexus). Even though the exact etiology of this phenomenon is not known, few predisposing factors have been documented in the literature. They include (1) adhesions between the annulus fibrosus, the PLL, and the dura mater – congenital or acquired, for example, postsurgery, (2) congenital narrowing of the spinal canal with less epidural space, or (3) congenital or iatrogenic fineness of the dura. These factors facilitate dural sheath tear into which the intrusion of disc material happens. Almost all the cases of intradural disc prolapse are confined to lower lumbar level. In our case also, the pathology was on L5–S1 Level.
In our case, the patient had a history of already diagnosed L5–S1 disc prolapse almost 1 year back and was treated conservatively. A case presenting similar way has been reported previously in the literature, suggestive of possible pathological explanation where a chronic disc causes chronic inflammation and thinning, before finally ending up with a dural defect and intradural migration of herniated disc.
MRI is the best imaging modality for the detection of intradural disc herniation. In cases where alternative diagnosis such as intradural or extradural lesions are suspected, gadolinium-enhanced contrast study is indicated. In MRI, disc fragments show hypointense signal on T1WI and hyperintense (80%) or isointense on T2WI.,, An interruption of PLL and doubtful dural breach should generate a possible diagnosis of intradural herniation. In gadolinium contrast study, herniated disc may show peripheral enhancement compared to tumors which show full enhancement., In our patient, no contrast study was done and MRI showed breach in the PLL, but dural breach was not confirmed in the MRI. In previous case reports also, most authors conclude that this kind of diagnosis is usually made intraoperatively., It has been reported in the literature that with the use of 3D high-resolution constructive interference in steady state (CISS), the sequence sensitivity of MRI in detecting intradural disc herniations can be improved significantly. 3D CISS sequence is similar to standard T2-weighted images commonly used to detect intradural diseases, such as redundant nerve root syndrome of the cauda equina or thoracic anterior spinal cord adhesion syndrome.
In most of the reported cases in the literature, the only preoperative finding suggestive of intradural herniation was discontinuity in the PLL in MRI., Some radiological signs that are specific to intradural herniation described in literature are “hawk-beak” sign on the axial MRI scan, which represented a beak-like appearance of the dura imparted by the sharp, compressing lesion and “Y-sign” on the sagittal MRI image which occurs when the disc fragment gradually peels off the arachnoid mater from the dural layer and occupies the subdural space., Another sign described in gadolinium-enhanced MRI is “dural tail” sign, which is a postcontrast linear thickening of the meninges that resembles a tail extending from the mass lesion., Even though this is relatively nonspecific and has been described in other lesions such as neuromas, chloromas, metastases, lymphoma, gliomas, large disc sequestrations, and granulomatous disease, this was the only indication for considering a dural extension in one case report in the literature.
| Conclusion|| |
Intradural disc herniation is an extremely rare phenomenon, and high amount of clinical suspicion is needed for preoperative diagnosis. Preoperative diagnosis can help in better planning and avoiding any intraoperative complications in these cases.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient (s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
| References|| |
Dandy WE. Serious complications of ruptured intervertebral disks. JAMA 1942;119:474-7.
Bonaroti EA, Welch WC. Posterior epidural migration of an extruded lumbar disc fragment causing cauda equina syndrome. Clinical and magnetic resonance imaging evaluation. Spine (Phila Pa 1976) 1998;23:378-81.
Ducati LG, Silva MV, Brandao MM, Romero FR, Zianini MA. Intradural lumbar disc herniation: report of five cases with literature review. Eur Spine J. 2013;22(Suppl3):S404-8.
D'Andrea G, Trillò G, Roperto R, Celli P, Orlando ER, Ferrante L. Intradural lumbar disc herniations: The role of MRI in preoperative diagnosis and review of the literature. Neurosurg Rev 2004;27:75-80.
Robe P, Martin D, Lenelle J, Stevenaert A. Posterior epidural migration of sequestered lumbar disc fragments. Report of two cases. J Neurosurg 1999;90:264-6.
Goncalves FG, Hanagandi PB, Torres CI, DelCarpio-O'Donovan R. Posterior migration of lumbar disc herniation – Imaging dilemma due to contrast contraindication: A case report. Radiol Bras 2012;45:170-2.
Yildizhan A, Paşaoğlu A, Okten T, Ekinci N, Aycan K, Aral O. Intradural disc herniations pathogenesis, clinical picture, diagnosis and treatment. Acta Neurochir (Wien) 1991;110:160-5.
Viswanathan VK, Shetty AP, Kanna RM, Mahesh A, Shanmuganathan R. Dorsally migrated epidural disc herniation with intradural extension: A rare clinical entity. Indian Spine J 2018;1:61-4. [Full text]
Hida K, Iwasaki Y, Abe H, Shimazaki M, Matsuzaki T. Magnetic resonance imaging of intradural lumbar disc herniation. J Clin Neurosci 1999;6:345-7.
Singh PK, Shrivastava S, Dulani R, Banode P, Gupta S. Dorsal herniation of cauda equina due to sequestrated intradural disc. Asian Spine J 2012;6:145-7.
Aydin MV, Ozel S, Sen O, Erdogan B, Yildirim T. Intradural disc mimicking: A spinal tumor lesion. Spinal Cord 2004;42:52-4.
Ozer E, Yurtsever C, Yücesoy K, Güner M. Lumbar intraradicular disc herniation: Report of a rare and preoperatively unpredictable case and review of the literature. Spine J 2007;7:106-10.
Sakoda A, Yamashita KI, Hayashida M, Iwamoto Y, Yamasaki R, Kira JI. A case of superficial siderosis ameliorated after closure of dural deficit detected by MRI-CISS (constructive interference in steady state) imaging. Rinsho Shinkeigaku 2017;57:180-3.
Crivelli L, Dunet V. Intradural lumbar disc herniation detected by 3D CISS MRI. BMJ Case Rep 2017. doi:10.1136/bcr-2017-221728.
Epstein NE, Syrquin MS, Epstein JA, Decker RE. Intradural disc herniations in the cervical, thoracic, and lumbar spine: Report of three cases and review of the literature. J Spinal Disord 1990;3:396-403.
Mahomet N, Seedat Y. The dural tail sign. SA J Radiol Dec 2011. Available from: <
http://www.sajr.org.za/index.php/sajr/article/view/361/480>. [Last accessed on 2021 Mar 15].
Whittaker CK, Bernhardt M. Magnetic resonance imaging shows gadolinium enhancement of intradural herniated disc. Spine (Phila Pa 1976) 1994;19:1505-7.
[Figure 1], [Figure 2], [Figure 3]