title: Slip Reduction Rate between Minimal Invasive and Conventional Unilateral Transforaminal Interbody Fusion in Patients with Low-Grade Isthmic Spondylolisthesis.
abstract: OBJECTIVE
  To compare the slip reduction rate and clinical outcomes between unilateral conventional transforaminal lumbar interbody fusion (conventional TLIF) and unilateral minimal invasive TLIF (minimal TLIF) with pedicle screw fixation for treatment of one level low-grade symptomatic isthmic spondylolisthesis.
  
  
  METHODS
  Between February 2008 and April 2012, 25 patients with low-grade isthmic spondylolisthesis underwent conventional TLIF (12 patients) and minimal TLIF (13 patients) in single university hospital by a single surgeon. Lateral radiographs of lumbar spine were taken 12 months after surgery to analyze the degree of slip reduction and the clinical outcome. All measurements were performed by a single observer.
  
  
  RESULTS
  The demographic data between conventional TLIF and minimal TLIF were not different. Slip percentage was reduced from 15.00% to 8.33% in conventional TLIF, and from 14.15% to 9.62% in minimal TLIF. In both groups, slip percentage was significantly improved postoperatively (p=0.002), but no significant intergroup differences of slip percentage in preoperative and postoperative were found. The reduction rate also not different between conventional TLIF (45.41±28.80%) and minimal TLIF (32.91±32.12%, p=0.318).
  
  
  CONCLUSIONS
  Conventional TLIF and minimal TLIF with pedicle screw fixation showed good slip reduction in patients with one level low-grade symptomatic isthmic spondylolisthesis. The slip percentage and reduction rate were similar in the conventional TLIF and minimal TLIF.
authors.affiliation: Department of Neurosurgery, Guro Teun Teun Hospital, Seoul, Korea.
authors.forename: Chang Hyun
authors.initials: CH
authors.lastname: Oh
authors.affiliation: Department of Neurosurgery, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Gyu Yeul
authors.initials: GY
authors.lastname: Ji
authors.affiliation: Department of Neurosurgery, Guro Teun Teun Hospital, Seoul, Korea.
authors.forename: Jae Kyun
authors.initials: JK
authors.lastname: Jeon
authors.affiliation: Department of Neurosurgery, Guro Teun Teun Hospital, Seoul, Korea.
authors.forename: Junho
authors.initials: J
authors.lastname: Lee
authors.affiliation: Department of Neurosurgery, Inha University College of Medicine, Incheon, Korea.
authors.forename: Seung Hwan
authors.initials: SH
authors.lastname: Yoon
authors.affiliation: Department of Neurosurgery, Inha University College of Medicine, Incheon, Korea.
authors.forename: Dong Keun
authors.initials: DK
authors.lastname: Hyun
keywords: Conventional; Minimal invasive; Reduction rate; Slip percentage; Transforamenal lumbar interbody fusion