117. Minimally invasive transforaminal lumbar interbody fusion increases late-term rates of pseudarthrosis versus open approach

Abstract

<h3>BACKGROUND CONTEXT</h3> Lumbar fusion has developed into an effective surgical treatment option for patients with various lumbar pathologies including discogenic pain, stenosis and spinal instability. Popular minimally-invasive (MI) fusion techniques, such as transforaminal lumbar interbody fusion (TLIF) have been increasingly utilized by spinal surgeons, offering similar clinical outcomes to traditional open approaches and often reporting decreased blood loss and complications in the long term. Despite a number of reports comparing open versus MI-TLIF, literature stratifying return to OR (RTO) complications between the two approaches by time after surgery is limited. Therefore, the purpose of this study was to determine the differences in early, late and long-term revision rates between open and MI-TLIF. <h3>PURPOSE</h3> To determine differences in early, late and long-term revision rates between MI and open TLIF. <h3>STUDY DESIGN/SETTING</h3> Retrospective cohort study. <h3>PATIENT SAMPLE</h3> This study included 423 consecutive patients from 2012-2018 with a minimum follow-up of 2 years. Of the total, 127 underwent open TLIF and 296 underwent MI-TLIF. <h3>OUTCOME MEASURES</h3> (1) Return to OR revision rate, (2) pseudarthrosis proportion, (3) ASD proportion. <h3>Methods</h3> A retrospective review was performed to identify all patients between 2012-2018 who underwent 1- or 2-level open or MI-TLIF with a minimum follow-up of 2 years. Demographic data were compared between groups. RTO complications were noted and grouped according to categories related to infection, neurologic, fusion status, hardware and global alignment. These complications were then stratified by early (<6 months), late (6 months-2 years), and long-term (>2 years) time periods. Standard binominal and categorical comparative analyses were performed. <h3>Results</h3> A total of 423 consecutive patients were included; 127 in the open TLIF cohort and 296 in the MI-TLIF cohort. There were 67 males and 60 females in the open TLIF group compared to 177 males and 119 females in the MI-TLIF group (p= 0.180). Mean age was 54.1 years (21.9-79.2). Mean follow-up for the open TLIF and MI-TLIF groups were 67.9 and 69.6 months, respectively (p= 0.633). The overall RTO rate was 10.8% in the MI-TLIF cohort and 11.8% in the open TLIF cohort (p= 0.764). The open TLIF cohort had a significantly lower incidence of pseudarthrosis requiring RTO at the late-term time point (p= 0.042). There were no significant differences with respect to rates of adjacent segment disease (ASD) or any other particular complication requiring RTO. RTO rates at respective time points were 2.4%, 5.7%, and 2.7% for the MI-TLIF group and 5.5%, 0.8%, and 5.5% for the open TLIF group. Subgroup analysis of single-level operations only (75 open TLIF vs 255 MI-TLIF) demonstrated a significantly lower incidence of pseudarthrosis and ASD at both the late- and long-term time points (p= <0.001) in the open TLIF cohort, with no significant differences between overall RTO rates or any other complication (p= 0.333). <h3>Conclusions</h3> Open and MI-TLIF have both been shown to provide equivalent long-term clinical outcomes. In this study, patients undergoing open TLIF had significantly lower rates of pseudarthrosis compared to MI-TLIF. Open TLIF should be considered in patients with risk factors for nonunion; however, larger cohort studies are required to corroborate these findings. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.