title: Para-split laminotomy: a rescue technique for split laminotomy approach in exploring intramedullary midline located pathologies.
abstract: OBJECTIVE
  Conventional posterior approaches, which may involve multilevel laminectomies and facetectomies, may lead to spinal deformities, instability, and subluxation. We developed the multilevel spinous process splitting and distraction laminotomy technique, which is an option for approaching midline intramedullary spinal pathologies with preservation of mechanically relevant bone and muscle structures. In some cases, midline splitting is not feasible or convenient because of anatomical differences of spinous processes and laminas. Our objective was to develop a minimally invasive rescue approach technique that makes it possible to remove intramedullary lesions but does not increase the risk of damage to the crucial posterior stabilizers of the spine.
  
  
  METHODS
  We used the para-split laminotomy technique for opening the spinal canal not in the midline but rather in the parasagittal plane. The technique can be combined with the basic split laminotomy technique. This novel technique was used in five adult patients with midline intramedullary pathologies of the cervical and cervicothoracic spine.
  
  
  RESULTS
  The operating field under the microscope was sufficient for tumor removal according to the keyhole concept. The approach used did not affect the extent of resection or neurologic outcome. The average number of split laminae was 6 (range: 3-10). Average follow-up was 18 months (range: 13-36 months). Histologic results were as follows: two ependymomas, two astrocytomas, and one primitive neuroectodermal tumor (PNET). To confirm the extension of resection, all patients underwent postoperative magnetic resonance imaging evaluations. The resections were complete in the cases of two ependymomas, subtotal in one astrocytoma, and partial in the other astrocytoma case and the PNET case. Computed tomography scans showed the extension of para-split approaches and the moderately disturbed bony structures. Instability was detected in none of the patients on the flexion-extension lateral radiographs during the follow-up period.
  
  
  CONCLUSIONS
  The minimally invasive multilevel para-split laminotomy approach as a rescue technique for split laminotomy is a safe and effective surgical procedure, suitable for exploring different intramedullary pathologies located in the midline of the spinal canal. This modified surgical approach fulfills the requirements of other minimally invasive techniques and lowers the risk of damage to the crucial posterior stabilizers of the spine; furthermore, disintegration of the vertebral arches and facet joints is reduced.
authors.affiliation: Department of Spinal Surgery, National Institute of Neurosurgery, Budapest, Hungary.
authors.forename: Csaba
authors.initials: C
authors.lastname: Padanyi
authors.affiliation: Department of Spinal Surgery, National Institute of Neurosurgery, Budapest, Hungary.
authors.forename: Janos
authors.initials: J
authors.lastname: Vajda
authors.affiliation: Department of Spinal Surgery, National Institute of Neurosurgery, Budapest, Hungary.
authors.forename: Peter
authors.initials: P
authors.lastname: Banczerowski
mesh_terms: D001254:Astrocytoma / Q000601:surgery; D002574:Cervical Vertebrae / Q000601:surgery*; D004806:Ependymoma / Q000601:surgery; D005260:Female; D006801:Humans; D007796:Laminectomy / Q000379:methods*; D008297:Male; D008875:Middle Aged; D018242:Neuroectodermal Tumors, Primitive / Q000601:surgery; D013120:Spinal Cord Neoplasms / Q000601:surgery*; D013904:Thoracic Vertebrae / Q000601:surgery*; D016896:Treatment Outcome