title: Herniation and entrapment of a nerve root secondary to an unrepaired small dural laceration at lumbar hemilaminectomies.
abstract: METHODS
  The authors encountered a unique case of nerve root herniation 9 days after multiple lumbar partial hemilaminectomies with discectomy were performed for lumbar canal stenosis combined with lumbar disc hernia.
  
  
  OBJECTIVE
  The treatment of this patient involved surgical repair even though the dural laceration was small and the arachnoid was intact.
  
  
  BACKGROUND
  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 arachnoid membrane.
  
  
  METHODS
  The patient presented with weakness of the right lower extremity and underwent partial hemilaminectomies and discectomy for lumbar canal stenosis. Nine days after surgery, he suddenly experience severe pain in the left S1 region. Neither myelography nor computed tomography-myelography revealed pathologic findings before the second operation. At surgery, herniation of the S1 nerve root was found. Surgical correction of the herniated nerve root at the level of the left L5 vertebra was performed.
  
  
  RESULTS
  This correction completely relieved the pain in the left S1 region.
  
  
  CONCLUSIONS
  This herniation resulted from an unrepaired minor dural laceration. The arachnoid membrane was intact during the first operation. Even a small tear in the spinal dura requires 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.
authors.affiliation: Department of Neurosurgery, National Cardio-Vascular Center, Osaka, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Nishi
authors.forename: N
authors.initials: N
authors.lastname: Hashimoto
authors.forename: Y
authors.initials: Y
authors.lastname: Takagi
authors.forename: T
authors.initials: T
authors.lastname: Tsukahara
mesh_terms: D017586:Diskectomy / Q000009:adverse effects; D004388:Dura Mater / Q000601:surgery; D006801:Humans; D007796:Laminectomy / Q000009:adverse effects*; D008161:Lumbosacral Region / Q000000981:diagnostic imaging / Q000601:surgery; D008297:Male; D008875:Middle Aged; D009192:Myelography; D009408:Nerve Compression Syndromes / Q000209:etiology*; D013115:Spinal Canal / Q000601:surgery; D013126:Spinal Nerve Roots / Q000000981:diagnostic imaging / Q000601:surgery*