Five-Year Outcomes of Minimally Invasive Versus Open Transforaminal Lumbar Interbody Fusion

STUDY DESIGN: Retrospective analysis of prospectively collected data. OBJECTIVE: To compare midterm clinical and radiological outcomes of minimally invasive surgery (MIS) versus open transforaminal lumbar interbody fusion (TLIF). SUMMARY OF BACKGROUND DATA: Open TLIF is a proven technique to achieve fusion in symptomatic spinal deformities and instabilities. The possible advantages of MIS TLIF include reduced blood loss, less pain, and shorter hospitalization. To date, there is no published data comparing their midterm outcomes. METHODS: From 2004-2007, 40 cases of open TLIF were matched paired with 40 cases of MIS TLIF for age, sex, body mass index, and the levels on which the spine was operated. Oswestry Disability Index, neurogenic symptom score, the 36-Item Short Form Health Survey, and visual analogue scale scores for back and leg pain were obtained before surgery, 6 months, 2 years, and 5 years after surgery. Fusion rates were assessed using Bridwell classification. RESULTS: Fluoroscopic time (MIS: 55.2 s, open: 16.4 s, P < 0.001) was longer in MIS cases. Operative time (MIS: 185 min, open: 166 min, P = 0.085) was not significantly longer in MIS cases. MIS had less blood loss (127 mL) versus open (405 mL, P < 0.001) procedures. Morphine use for MIS cases (8.5 mg) was less compared with open (24.2 mg, P = 0.006). Patients who underwent MIS (1.5 d) ambulated earlier than those who underwent open fusion (3 d, P < 0.001). Patients who underwent MIS (3.6 d) had shorter hospitalization than those who underwent open fusion (5.9 d, P < 0.001). Both groups showed significant improvement in Oswestry Disability Index, neurogenic symptom score, back and leg pain, SF-36 scores at 6 months until 5 years with no significant differences between them. Grade 1 fusion was achieved in 97.5% of both groups at 5 years. The overall complication rate was 20% for the open group and 15% for MIS group (P = 0.774), including 4 cases of adjacent segment disease for each group. CONCLUSION: MIS TLIF is comparable with open TLIF in terms of midterm clinical outcomes and fusion rates with the additional benefits of less initial postoperative pain, less blood loss, earlier rehabilitation, and shorter hospitalization.