Systematic review and meta-analysis of minimally invasive transforaminal lumbar interbody fusion rates performed without posterolateral fusion

The need for posterolateral fusion (PLF) in addition to interbody fusion during minimally invasive (MIS) transforaminal lumbar interbody fusion (TLIF) has yet to be established. Omitting a PLF significantly reduces overall surface area available for achieving a solid arthrodesis, however it decreases the soft tissue dissection and costs of additional bone graft. The authors sought to perform a meta-analysis to establish the fusion rate of MIS TLIF performed without attempting a PLF. We performed an extensive Medline and Ovid database search through December 2010 revealing 39 articles. Inclusion criteria necessitated that a one or two level TLIF procedure was performed through a paramedian MIS approach with bilateral posterior pedicle screw instrumentation and without posterolateral bone grafting. CT scan verified fusion rates were mandatory for inclusion. Seven studies (case series and case-controls) met inclusion criteria with a total of 408 patients who underwent MIS TLIF as described above. The mean age was 50.7 years and 56.6% of patients were female. A total of 78.9% of patients underwent single level TLIF. Average radiographic follow-up was 15.6 months. All patients had local autologous interbody bone grafting harvested from the pars interarticularis and facet joint of the approach side. Either polyetheretherketone (PEEK) or allograft interbody cages were used in all patients. Overall fusion rate, confirmed by bridging trabecular interbody bone on CT scan, was 94.7%. This meta-analysis suggests that MIS TLIF performed with interbody bone grafting alone has similar fusion rates to MIS or open TLIF performed with interbody supplemented with posterolateral bone grafting and fusion.