title: Open and minimally invasive transforaminal lumbar interbody fusion: comparison of intermediate results and complications.
abstract: METHODS
  Prospective study.
  
  
  OBJECTIVE
  To compare clinical and radiological outcomes of open vs. minimally invasive transforaminal lumbar interbody fusion (MI-TLIF).
  
  
  BACKGROUND
  MI-TLIF promises smaller incisions and less soft tissue dissection resulting in lower morbidity and faster recovery; however, it is technically challenging.
  
  
  METHODS
  Twenty-five patients with MI-TLIF were compared with 25 matched open TLIF controls. A minimum 2 year follow-up and a statistical analysis of perioperative and long-term outcomes were performed. Potential complications were recorded.
  
  
  RESULTS
  The mean ages for the open and MI-TLIF cases were 44.4 years (range, 19-69 years) and 43.6 years (range, 20-69 years), respectively. The male:female ratio was 13:12 for both groups. Average follow-up was 26.9 months for the MI-TLIF group and 29.3 months for the open group. Operative duration was significantly longer in the MI-TLIF group than that in the open group (p<0.05). No differences in estimated blood loss, duration to ambulation, or length of stay were found. Significant improvements in the Oswestry disability index and EQ-5D functional scores were observed at 6-, 12-, and 24-months in both groups, but no significant difference was detected between the groups. Fusion rates were comparable. Cage sizes were significantly smaller in the MI-TLIF group at the L5/S1 level (p<0.05). One patient had residual spinal stenosis at the MI-TLIF level, and one patient who underwent two-level MI-TLIF developed a deep vein thrombosis resulting in a pulmonary embolism.
  
  
  CONCLUSIONS
  MI-TLIF and open TLIF had comparable long-term benefits. Due to technical constraints, patients should be advised on the longer operative time and potential undersizing of cages at the L5S1 level.
authors.affiliation: Department of Orthopaedic Surgery, National University Health System, Singapore.
authors.forename: Hwee Weng Dennis
authors.initials: HW
authors.lastname: Hey
authors.affiliation: Centre for Spine and Scoliosis Surgery, Paramount and Mount Elizabeth Medical Centre, Singapore.
authors.forename: Hwan Tak
authors.initials: HT
authors.lastname: Hee
keywords: Duration of surgery; Interbody cage; Minimally invasive; Open; Oswestry disability index; Transforaminal lumbar interbody fusion