title: Lumbar Interspinous Process Fixation and Fusion with Stand-Alone Interlaminar Lumbar Instrumented Fusion Implant in Patients with Degenerative Spondylolisthesis Undergoing Decompression for Spinal Stenosis.
abstract: METHODS
  Prospective cohort study.
  
  
  OBJECTIVE
  To assess the ability of a stand-alone lumbar interspinous implant (interspinous/interlaminar lumbar instrumented fusion, ILIF) associated with bone grafting to promote posterior spine fusion in degenerative spondylolisthesis (DS) with vertebral instability.
  
  
  BACKGROUND
  A few studies, using bilateral laminotomy (BL) or bilateral decompression by unilateral laminotomy (BDUL), found satisfactory results in stenotic patients with decompression alone, but others reported increased olisthesis, or subsequent need for fusion in DS with or without dynamic instability.
  
  
  METHODS
  Twenty-five patients with Grade I DS, leg pain and chronic low back pain underwent BL or BDUL and ILIF implant. Olisthesis was 13% to 21%. Follow-up evaluations were performed at 4 to 12 months up to 25 to 44 months (mean, 34.4). Outcome measures were numerical rating scale (NRS) for back and leg pain, Oswestry disability index (ODI) and short-form 36 health survey (SF-36) of body pain and function.
  
  
  RESULTS
  Fusion occurred in 21 patients (84%). None had increased olisthesis or instability postoperatively. Four types of fusion were identified. In Type I, the posterior part of the spinous processes were fused. In Type II, fusion extended to the base of the processes. In Type III, bone was present also around the polyetheretherketone plate of ILIF. In Type IV, even the facet joints were fused. The mean NRS score for back and leg pain decreased by 64% and 80%, respectively. The mean ODI score was decreased by 52%. SF-36 bodily pain and physical function mean scores increased by 53% and 58%, respectively. Computed tomography revealed failed fusion in four patients, all of whom still had vertebral instability postoperatively.
  
  
  CONCLUSIONS
  Stand-alone ILIF with interspinous bone grafting promotes vertebral fusion in most patients with lumbar stenosis and unstable Grade I DS undergoing BL or BDUL.
authors.affiliation: Department of Saimlal, Section of Orthopedic Surgery, Clinica Ortopedica, Università Sapienza, Rome, Italy.
authors.forename: Franco
authors.initials: F
authors.lastname: Postacchini
authors.affiliation: Ospedale Israelitico, Rome, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Postacchini
authors.affiliation: Rome American Hospital, Rome, Italy.
authors.forename: Pier Paolo Maria
authors.initials: PP
authors.lastname: Menchetti
authors.affiliation: Department of Saimlal, Section of Orthopedic Surgery, Clinica Ortopedica, Università Sapienza, Rome, Italy.
authors.forename: Pasquale
authors.initials: P
authors.lastname: Sessa
authors.affiliation: Department of Saimlal, Section of Orthopedic Surgery, Clinica Ortopedica, Università Sapienza, Rome, Italy.
authors.forename: Michela
authors.initials: M
authors.lastname: Paolino
authors.affiliation: Department of Saimlal, Section of Orthopedic Surgery, Clinica Ortopedica, Università Sapienza, Rome, Italy.
authors.forename: Gianluca
authors.initials: G
authors.lastname: Cinotti
keywords: Degenerative spondylolisthesis; Interspinous fusion; Laminotomy; Lumbar spine; Lumbar stenosis