title: Initial clinical outcomes of minimally invasive lateral lumbar interbody fusion in degenerative lumbar disease: a preliminary report on the experience of a single institution with 30 cases.
abstract: OBJECTIVE
  The object of this study was to evaluate the clinical and radiological outcomes of minimally invasive lateral lumbar interbody fusion.
  
  
  METHODS
  This study included 30 patients who underwent minimally invasive lateral lumbar interbody fusion at our hospital between May 2011 and February 2012 for the following diagnoses: degenerative disc disease, adjacent-segment degeneration, degenerative spondylolisthesis and lumbar degenerative scoliosis. Pain assessment was reported from 0 to 10 using a subjective visual analog scale (VAS) upon admission and at every follow-up day. Lumbar X-rays were obtained in the standing position upon admission and the 1st and 5th postoperative day, and at every follow-up day after the operation. The heights of the intervertebral disc space and neural foramen were measured using an electronic caliper with the PACS software. The surgical outcome was assessed as excellent, good, fair or poor using the Odom scale at the last follow-up.
  
  
  RESULTS
  The mean VAS for low back pain were 4.93±1.47 on admission and 2.01±1.35 at last follow-up, respectively, and for leg pain, the scores were 4.87±2.16 on admission and 1.58±1.52 at last follow-up. The mean height of intervertebral disc space increased by 34% (7.93±2.33 preoperatively, and 11.09±4.33 immediately after surgery, p<0.01). The mean height of neural foramen also increased by 6.4% without any statistical significance (19.17±2.84 preoperatively, and 20.49±4.50 immediately after the surgery). Minimally invasive lateral lumbar interbody fusion was successful in 27 patients (90%) at last follow-up. Surgical complications were reported as transient postoperative thigh sensory changes (5 patients, 16.7%), transient psoas muscle weakness (3 patients, 10%), cage migration (2 patients, 6.7%), lumbar plexus injury (1 patient, 3.3%), and pain aggravation (1 patient, 3.3%).
  
  
  CONCLUSIONS
  The minimally invasive lateral lumbar interbody fusion is a safe and effective procedure for treating degenerative lumbar disease with good outcomes and moderate complications. Further follow-up is necessary to establish its safety and efficacy.
authors.affiliation: Department of Neurosurgery, Yonsei University College of Medicine, Severance Hospital, The Spine and Spinal Cord Institute, Seoul, Korea.
authors.forename: Young Cheol
authors.initials: YC
authors.lastname: Na
authors.affiliation: Department of Neurosurgery, Yonsei University College of Medicine, Severance Hospital, The Spine and Spinal Cord Institute, Seoul, Korea.
authors.forename: Hyo Sang
authors.initials: HS
authors.lastname: Lee
authors.affiliation: Department of Neurosurgery, Yonsei University College of Medicine, Severance Hospital, The Spine and Spinal Cord Institute, Seoul, Korea.
authors.forename: Dong Ah
authors.initials: DA
authors.lastname: Shin
authors.affiliation: Department of Neurosurgery, Yonsei University College of Medicine, Severance Hospital, The Spine and Spinal Cord Institute, Seoul, Korea.
authors.forename: Yoon
authors.initials: Y
authors.lastname: Ha
authors.affiliation: Department of Neurosurgery, Yonsei University College of Medicine, Severance Hospital, The Spine and Spinal Cord Institute, Seoul, Korea.
authors.forename: Keung Nyun
authors.initials: KN
authors.lastname: Kim
authors.affiliation: Department of Neurosurgery, Yonsei University College of Medicine, Severance Hospital, The Spine and Spinal Cord Institute, Seoul, Korea.
authors.forename: Do Heum
authors.initials: DH
authors.lastname: Yoon
keywords: Complication; Spinal fusion; Treatment outcome