The Use of a Wilson Kyphosis Frame Results in Minimal Loss of Lordosis Correction after Single Level Minimally Invasive TLIF at L4-5 or L5-S1

Study DesignRetrospective cohort study.ObjectiveDetermine if the use of a Wilson kyphosis frame during single level minimally invasive transforaminal lumbar interbody fusion (MIS TLIF) at L4-5 or L5-S1 impacts postoperative lumbar lordosis.MethodsA retrospective analysis of patients who underwent a single level MIS TLIF at L4-5 and L5-S1 from 1/1/2016 to 1/1/2021 was performed. Patient demographics were collected, and radiographic measurements preoperatively and 6 months postoperatively were performed. Our primary outcome was "delta lumbar lordosis" (delta LL), or the difference between pre-operative and 6 month postoperative lumbar lordosis. Statistical analysis was performed using step-wise multivariate linear regressions.ResultsA total of 180 patients were included. Mean age was 58.5 ± 11.8 years and 48.3% were female. Mean BMI was 28.6 ± 5.6. Wilson positioning frames were used in 96/180 (53.3%) procedures. Use of a Wilson Frame was independently predictive of 2.5° reduced delta LL (Coeff -2.5, 95% CI -4.1 to -0.9). However, use of a Wilson frame was not found to be independently associated with postoperative mismatch between pelvic incidence and lumbar lordosis.ConclusionsUse of a Wilson kyphosis frame during single level MIS TLIF at L4-5 and L5-S1 resulted in a loss of 2.5° of lordosis compared with those patients who had a MIS TLIF without a Wilson frame. The clinical impact of this loss over long-term follow-up will be the subject of future studies.