A study comparing instrumented unilateral transforaminal lumbar interbody fusion (TLIF) with bilateral instrumented TLIF, published ahead of print in The Spine Journal, has found that the minimally invasive technique has a significantly shorter operating time, significantly less blood loss, and significantly reduced implant costs than bilateral TILF.
Huaming Xue, Department of Orthopaedic Surgery, Shanghai Yangpu District Central Hospital, Shanghai, China, and colleagues wrote that the use of unilateral or bilateral instrumentation was a controversial issue in spinal fusion surgery. They explained it was unclear from biomechanical studies, whether there was a significant difference between unilateral pedicle screw instrumentation and bilateral pedicle screw instrumentation for interbody fusion. They added: “To answer this question, it was really necessary to carry out a clinical comparative study.”
Therefore, Xue et al randomised 80 patients, over a four-year period, into two groups: unilateral pedicle screw instrumented TLIF using a minimally invasive technique (37); bilateral pedicle screw instrumented TLIF using a traditional open approach (43). All patients had low-back pain and unilateral radicular pain, underwent six months of non-operative management prior to surgery, and all had some form of degenerative lumbar disease (ranging from spinal stenosis with spondylolisthesis to recurrent lumbar disc herniation with significant mechanical back pain and unilateral radiculopathy).
After a mean follow-up of 25.3 months, patients in the unilateral TLIF group had significantly shorter operative time and less blood loss than patients in the bilateral TLIF group. This finding was true for both single and double level cases. For example, the operative time was 136.3±20.1 minutes in group one vs. 245.1±26.5 minutes (p<0.01) in group two in single cases and 200.2±12.1 minutes vs. 262.4±18.1 minutes (p<0.01), respectively, in double cases. Also, the cost of the minimally invasive TLIF technique was significantly reduced compared with the open TLIF technique: US$ 3,943.3 (€2,986.88 at current exchange rate) ±19.5 vs. US$6,756.3 (€5,117.57 at current exchange rate) ±50.8, respectively (p<0.01).
All patients, regardless of which group they were in, had significant improvements in their Visual Analogue Scale scores, the Oswestry Disability Index, and modified Prolo scores, and there were no significant differences between the groups. The total fusion rate, rate of screw failure, and general complication rate also did not differ significantly between groups.
Xue et al concluded: “In summary, unilateral pedicle screw instrumentation TLIF is a viable treatment option that produces better results, especially in terms of operative time, blood loss, implant costs, and hospital time for single-level disease.” They added that an improved study design and longer period of follow-up were needed to confirm their results.