The Spine Blog

Friday, November 8, 2013

MIS vs. Open TLIF

Minimally invasive TLIF has had increasing popularity over the past decade due to purported advantages in terms of decreased post-operative pain, lower infection rates, and lower blood loss. Skeptics of the procedure have cited a steep learning curve associated with higher complication rates, increased OR and fluoroscopy time, lower fusion rates, and minimal measurable benefits for patients. In an attempt to provide data on the topic, Dr. Seng and his colleagues from Singapore published a matched-pair cohort study comparing short term as well as longer term outcomes between patients treated with open and MIS-TLIF. Forty MIS-TLIF patients with either spondylolisthesis (80% of patients) or degenerative disk disease (20% of patients) with stenosis were selected, and the authors then created an open TLIF cohort matched on age, gender, BMI, and operative level (only one level cases were included). The groups were similar at baseline, though the open group tended to have more medical comorbidities and worse SF-36 scores (role physical functioning and vitality were significantly worse). From six months to 5 years of follow-up, patient reported outcome measures including VAS back and leg pain, ODI, Neurogenic Symptom Score, and SF-36 scores were similar, as was fusion rate. The MIS-TLIF group had significantly less blood loss, shorter times to ambulation and discharge, and lower post-operative morphine use. Additionally, 10% of patients in the open group required a transfusion, while none were required in the MIS group (difference not significant). The open TLIF group had a shorter OR time and less use of intra-operative fluoroscopy. These results are in line with prior observational studies suggesting some perioperative and short-term advantages to MIS-TLIF but no long-term differences.


Debate on this topic has been longstanding, and the current study adds some data that is consistent with what is in the literature. However, given that this represents another observational trial prone to selection and reporting bias, the question remains unanswered. There are no double-blinded RCTs on the topic, and such a study design would be required to definitively determine how the two techniques stack up against one another. Other than blood loss, most of the short term outcomes like time to ambulation and discharge and narcotic usage can be biased in an unblinded study as patients and caregivers alike have different expectations depending on the type of surgery performed. Additionally, the surgeons selected the patients for the two different operations, and there were likely unmeasured patient factors that contributed to this decision. Inspection of their baseline characteristics demonstrates that the open TLIF group was somewhat less healthy and active compared to the MIS-TLIF group. Prior to wide adoption of MIS-TLIF, a blinded RCT should be performed comparing short and long term outcomes between the two techniques. MIS-TLIF has been shown to have a relatively long learning curve associated with an increased complication rate as surgeons learn the technique, and a tangible benefit should be demonstrated before surgeons subject patients to their learning curve.1,2 Determining the indications for TLIF is another topic altogether.


Please read Dr. Seng’s article on this topic in the November 1 issue. Does this article change how you view the advantages and disadvantages of MIS-TLIF? Let us know by leaving a comment on The Spine Blog.

Adam Pearson, MD, MS

Associate Web Editor



1.            Silva PS, Pereira P, Monteiro P, Silva PA, Vaz R. Learning curve and complications of minimally invasive transforaminal lumbar interbody fusion. Neurosurg Focus 2013;35:E7.

2.            Lee JC, Jang HD, Shin BJ. Learning curve and clinical outcomes of minimally invasive transforaminal lumbar interbody fusion: our experience in 86 consecutive cases. Spine 2012;37:1548-57.