Intradural disc herniation at the L1-2 level

Intradural disc herniations (IDHs) are rare, are difficult to diagnose on preoperative MR/CT imaging, and typically, are most readily confirmed at the time of surgery. However, one of the greatest challenges posed by these lesions, is the repair of the ventral dural rent.

A 55-year-old male with a 20-year history of lumbago presented with low back pain and right lower extremity sciatica of 3 months' duration. The MR and CT studies showed a compressive lesion at the L1-2 level. There was no original suspicion that this was an IDH. At surgery, performed under the operating microscope, a subtotal L1-L2 laminectomy was performed (i.e. while lysing severe adhesions between the posterior longitudinal ligament and the ventral dura, a traumatic durotomy occurred. White, spongious, friable, soft tissue, and free-floating disc fragments extruded through the durotomy site. Notably, it was initially considered to be a tumor rather than a disc. Once all fragments had been delivered, unsuccessful attempts were made to repair the ventral dura. Further efforts were curtailed due to concern that they would result in damage to multiple ventral nerve rootlets. Despite the lack of primary dural repair, the secondary measures resulted in no postoperative recurrent cerebrospinal fluid leakage (CSF) and a smooth postoperative surgical course.

IDH at the L1-2 level is rare, and preoperative MR/CT studies may not always document their intradural location. Ideally, ventral dural tears attributed to these lesions should be directly repaired and/or managed with additional adjunctive CSF leak repair techniques (i.e. muscle patch grafts, microfibrillar collagen, and fibrin sealants).