RT Journal Article SR Electronic T1 Minimally Invasive Transforaminal Lumbar Interbody Fusion: Comparison of Isthmic Versus Degenerative Spondylolisthesis JF International Journal of Spine Surgery JO Int J Spine Surg FD International Society for the Advancement of Spine Surgery SP 115 OP 124 DO 10.14444/7015 VO 14 IS 2 A1 DUSTIN H. MASSEL A1 BENJAMIN C. MAYO A1 GRANT D. SHIFFLETT A1 DANIEL D. BOHL A1 PHILIP K. LOUIE A1 BRYCE A. BASQUES A1 WILLIAM W. LONG A1 KRISHNA D. MODI A1 FADY Y. HIJJI A1 ANKUR S. NARAIN A1 KERN SINGH YR 2020 UL http://ijssurgery.com//content/14/2/115.abstract AB Background: Minimally invasive transforaminal lumbar interbody fusion (MIS TLIF) is a common surgical procedure for treatment of degenerative spondylolisthesis (DS) but remains controversial for treatment of isthmic spondylolisthesis (IS). Few studies have compared IS and DS outcomes after MIS TLIF. Therefore, the objective of the current study was to compare outcomes of patients with IS and DS after MIS TLIF.Methods: A retrospective cohort analysis was performed on a prospectively maintained database of patients who underwent a primary, 1-level MIS TLIF for grade I or II IS or DS. Grade I and II DS and grade I IS patients were treated with MIS TLIF via a unilateral tubular approach, whereas the grade II IS patients were treated via a bilateral tubular approach. Differences in patient demographics and preoperative characteristics were assessed using independent sample t tests and χ2 tests. The type of spondylolisthesis and its effect on postoperative outcomes was analyzed using Poisson regression with robust error variance (binary outcomes) or linear regression (continuous outcomes) adjusted for preoperative characteristics. Subgroup analysis comparing grade I IS versus DS and grade II IS versus DS was performed.Results: A total of 223 patients were included (IS: 62 [27.8%]; DS: 161 [72.2%]). IS patients were younger (P < .001), had a lower comorbidity burden (P < .001), and a greater incidence of grade II spondylolisthesis (P < .001) at L5–S1 (P < .001) than the DS cohort. Patients with IS experienced longer operative times (P < .001) and lower, but not statistically significant, arthrodesis rates compared to the DS cohort. No differences were observed in the remaining preoperative patient characteristics, perioperative or postoperative outcomes.Conclusions: Despite being younger and having a lower comorbidity burden than the DS cohort, similar outcomes were observed after MIS TLIF for IS patients.Level of Evidence: 3.Clinical Relevance: These results suggest MIS TLIF is an appropriate treatment option for IS patients despite the increased instability inherent with IS.