title: Spinous Process-Splitting Hemilaminoplasty for Intradural and Extradural Lesions.
abstract: OBJECTIVE
  To describe a novel spinous process-splitting hemilaminoplasty technique for the surgical treatment of intradural and posterior epidural lesions that promotes physiological restoration.
  
  
  METHODS
  The spinous process was split, the area of the facet lamina junction was drilled, and en bloc hemilaminectomy was then performed. After removing intradural and posterior epidural lesions, we fitted the previously en bloc-removed bone to the pre-surgery same shape, and held it in place with non-absorbable sutures. Surgery was performed on 16 laminas from a total of nine patients between 2011 and 2014. Bony union of the reconstructed lamina was assessed using computed tomography (CT) at 6 months after surgery.
  
  
  RESULTS
  Spinous process-slitting hemilaminoplasty was performed for intradural extramedullary tumors in eight patients and for ossification of the ligament flavum in one patient. Because we were able to visualize the margin of the ipsilateral and contralateral dura, we were able to secure space for removal of the lesion and closure of the dura. None of the cases showed spinal deformity or other complications. Bone fusion and maintenance of the spinal canal were found to be perfect on CT scans.
  
  
  CONCLUSIONS
  The spinous process-splitting hemilaminoplasty technique presented here was successful in creating sufficient space to remove intradural and posterior epidural lesions and to close the dura. Furthermore, we were able to maintain the physiological barrier and integrity after surgery because the posterior musculature and bone structures were restored.
authors.affiliation: Department of Neurological Surgery, Gangneung Asan Hospital, University of Ulsan College of Medicine, Gangneung, Korea.
authors.forename: Young-Seok
authors.initials: YS
authors.lastname: Lee
authors.affiliation: Department of Neurosurgery, Chung-Ang University College of Medicine, Seoul, Korea.
authors.forename: Young-Baeg
authors.initials: YB
authors.lastname: Kim
authors.affiliation: Department of Neurosurgery, Chung-Ang University College of Medicine, Seoul, Korea.
authors.forename: Seung-Won
authors.initials: SW
authors.lastname: Park
keywords: Intradural and posterior extradural lesion; Physiological integrity; Spinous process-splitting hemilaminoplasty