title: Minimally invasive multi-level posterior lumbar interbody fusion using a percutaneously inserted spinal fixation system : technical tips, surgical outcomes.
abstract: OBJECTIVE
  There are technical limitations of multi-level posterior pedicle screw fixation performed by the percutaneous technique. The purpose of this study was to describe the surgical technique and outcome of minimally invasive multi-level posterior lumbar interbody fusion (PLIF) and to determine its efficacy.
  
  
  METHODS
  Forty-two patients who underwent mini-open PLIF using the percutaneous screw fixation system were studied. The mean age of the patients was 59.1 (range, 23 to 78 years). Two levels were involved in 32 cases and three levels in 10 cases. The clinical outcome was assessed using the visual analog scale (VAS) and Low Back Outcome Score (LBOS). Achievement of radiological fusion, intra-operative blood loss, the midline surgical scar and procedure related complications were also analyzed.
  
  
  RESULTS
  The mean follow-up period was 25.3 months. The mean LBOS prior to surgery was 34.5, which was improved to 49.1 at the final follow up. The mean pain score (VAS) prior to surgery was 7.5 and it was decreased to 2.9 at the last follow up. The mean estimated blood loss was 238 mL (140-350) for the two level procedures and 387 mL (278-458) for three levels. The midline surgical scar was 6.27 cm for two levels and 8.25 cm for three level procedures. Complications included two cases of asymptomatic medial penetration of the pedicle border. However, there were no signs of neurological deterioration or fusion failure.
  
  
  CONCLUSIONS
  Multi-level, minimally invasive PLIF can be performed effectively using the percutaneous transpedicular screw fixation system. It can be an alternative to the traditional open procedures.
authors.affiliation: Department of Neurosurgery, Daejeon Hurisarang Hospital, Daejeon, Korea.
authors.forename: Hyeun Sung
authors.initials: HS
authors.lastname: Kim
authors.forename: Keun Ho
authors.initials: KH
authors.lastname: Park
authors.forename: Chag Il
authors.initials: CI
authors.lastname: Ju
authors.forename: Seok Won
authors.initials: SW
authors.lastname: Kim
authors.forename: Seung Myung
authors.initials: SM
authors.lastname: Lee
authors.forename: Ho
authors.initials: H
authors.lastname: Shin