[Transforaminal lumbar interbody fusion: goals of the minimal invasive approach]

Transforaminal lumbar interbody fusion (TLIF) is an effective technique, which can achieve a fusion rate of up to 90%. The minimally invasive approach has become increasingly popular because it is able to minimize iatrogenic soft tissue and muscle injury. Although the minimally invasive TLIF technique has gained popularity, its effectiveness compared with open TLIF has yet to be established. The authors prospectively compared the outcomes of patients who underwent mini-open TLIF with patients who underwent open TLIF.

Between 2007 and 2008, 50 patients underwent TLIF for grade 1 spondylolisthesis; 25 mini-open TLIF and 25 open TLIF. The mean age in each group was 48years, and there was no statistically significant difference between the groups. Data were collected perioperatively. Pain and functional disability were measured using a visual analogue scale (VAS) and the Oswestry disability index (ODI) at 3months, 6months, 1year and 2years. In addition, foraminal and disc height were measured at the same intervals and the fusion was evaluated at 1year on CT-scan. Soft tissue damage was evaluated by measuring the serum myoglobin and creatine phosphokinase activity.

The mean VAS improved from 7 to 2.8 and the ODI decreased from 30/50 to 15/50 and fusion rate at 1 year was 98%. There was no statistical difference for the clinical and radiological outcomes between the groups. The mean operative time was 186min for the open group, 170min for the mini-open group (P<0.05) and the mean blood loss was 486mL for the open group and 148mL for the mini-open group (P<0.01).

The mini-open TLIF procedure for symptomatic low grade spondylolisthesis is an effective option which achieves similar clinical and radiological outcomes and reduces perioperative morbidity as well as soft tissue damage.