HERNIATION AND ENTRAPMENT OF A NERVE ROOT SECONDARY TO AN UNREPAIRED SMALL DURAL LACERATION AT LUMBAR HEMILAMINECTOMIES

Study Design. The authors encountered a unique case of nerve root hern iation 9 days after multiple lumbar partial hemilaminectomies with dis cectomy were performed for lumbar canal stenosis combined with lumbar disc hernia. Objective. The treatment of this patient involved surgica l repair even though the dural laceration was small and the arachnoid was intact. Summary of Background Data. There have been no reports of nerve root herniation into the facet joint through the arachnoid space after laminectomy, except in cases of extradural distention of the ar achnoid membrane. Methods. The patient presented with weakness of the right lower extremity and underwent partial hemilaminectomies for lumb ar canal stenosis. Nine days after surgery, he suddenly experience sev ere pain in the left S1 region. Neither myelography nor computed tomog raphy-myelography revealed pathologic findings before the second opera tion. At surgery, herniation of the S1 nerve root was found. Surgical correction of the herniated nerve root at the level of the left L5 ver tebra was performed. Results. This correction completely relieved the pain in the left S1 region. Conclusion. This herniation resulted from an unrepaired minor dural laceration. The arachnoid membrane was intac t during the first operation. Even a small tear in the spinal dura req uires surgical closure to prevent herniation and entrapment of a nerve root. It is necessary to repair even small dural lacerations with no spinal fluid leakage during spinal surgery.