Intradural lumbar disc herniation with cauda equina syndrome: Case report and recent advances

Abstract

Introduction: Intradural lumbar disc herniations (IDDH) are unusual and represent less than 0.3% of all lumbar disc herniations. They have a higher incidence of cauda equina syndrome. The possibility of intradural disc herniation is often missed on Magnetic Resonance Imaging (MRI) and during surgery if the size of the disc prolapse is inconsistent with the compression seen on the MRI. In such situations, the possibility of IDDH should be suspected.

Research question: How to diagnose intradural disc herniation pre-operatively? Surgical techniques if the intra-dural disc herniation is encountered intra-operatively.

Material and methods: In this article, we describe a case report of an intradural disc herniation (IDDH) causing cauda equina syndrome at the L4-5 level and who underwent surgical decompression. This case report highlights that by doing a dorsal durotomy and by using microsurgical techniques, excision of the intradural disc fragment can be achieved without any rootlet injury.

Results: At a 2-year follow-up, the patient has recovered completely from motor weakness and bowel and bladder incontinence.

Discussion and conclusion: Though uncommon intra-dural disc herniation can be diagnosed pre-operatively by its characteristic signs or by using newer techniques like 3-dimensional constructive interference in steady state (CISS) MRI. Intra-operative ultrasonography (IOUS) is a handy tool to localise and diagnose intra-dural disc herniation intra-operatively and its use is encouraged. Timely intervention can lead to acceptable outcomes even with cauda equina syndrome.

Keywords: Cauda equina syndrome(CES); Constructive Interference in Steady State(CISS) MRI; Discectomy; Intra-operative ultrasonography(IOUS); Intradural disc herniation(IDDH); Lumbar herniated disc.

Fig. 1

Preoperative X-ray showed calcified annulus at L1-2, L2-3 and L4-5 with anterior bridging osteophytes.

Fig. 2

Sagittal T2 weighted and STIR(Short tau inversion recovery) MRI showing abrupt disruption of PLL and intradural location of disc fragment at L4-5 level. Canal stenosis at L1-2 and L2-3 levels is also observed.

Fig. 3

Axial images of L1-2 and L2-L3 show canal stenosis with compression of the exiting nerve root. Axial MRI of L4-5 showing beak-like left posterolateral extrusion of disc fragment protruding into the dural sac occupying most of the canal diameter at L4-5 level (hawk-beak sign).

Fig. 4

Myelogram showing canal stenosis at respective levels.

Fig. 5

Intra-operative Ultrasonography picture showing rootlets with an intra-dural mass.

Fig. 6

Intraoperative image showing tense dura after laminectomy with disc fragment seen after dorsal durotomy. Careful dissection of rootlets from the disc fragment to facilitate its expulsion.

Fig. 7

Disc fragment excised measuring about 2.7cm × 0.8mm from the dorsal durotomy.