Achieving Greater Segmental Lordosis with Intraoperative Mechanical Hinging and Bilateral Facetectomies in Minimally Invasive Transforaminal Lumbar Interbody Fusion

Study Design. Retrospective study. Objective. We add to the literature a series of TLIF cases using a minimally invasive surgical (MIS) approach with the use of a mechanically hinging operating table and bilateral facetectomies (Smith-Petersen osteotomy, SPO). Summary of Background Data. Transforaminal lumbar interbody fusion (TLIF) with interbody cages is understood to have a poor preservation of lordosis in the literature and can often be a kyphosing procedure. Intraoperative flexion using a hinged operating table to increase interbody spacing for cage placement followed by intraoperative extension to facilitate osteotomy closure, may allow a greater degree of segmental lordosis to be achieved and maintained. Materials and Methods. We identified patients from 2018 to 2024 who underwent MIS-TLIF at our institution. Clinical and operative variables collected included age, sex, body mass index, hemoglobin A1C, smoking status, post-surgical Baastrup’s disease, indications for surgery, fusion level, and spacer details. Radiographic variables included segmental lordosis (SL) at preoperative, intraoperative, and postoperative timepoints. Outcomes included post-surgical correction and 6-month correction. Clinical and radiographic findings were analyzed with standard statistical approaches. Results. 202 patients met inclusion criteria. For 1-level and 2-level fusion, the mean post-surgical correction was 5.0 degree and 4.6 degrees respectively, and the mean 6-month correction was 4.6 degrees and 6.6 degrees respectively. Significant differences in lordosis were appreciated between preoperative and postoperative scans for both 1-level ( P <0.0001) and 2-level ( P =0.0017) fusion, and between preoperative and 6-month scans for 1-level ( P <0.0001) fusion. Negative correlations were appreciated between preoperative and postoperative SL (R=−0.31, P =0.0001) and preoperative SL and 6-month correction (R=−0.19, P =0.0289) for 1-level fusions. Conclusion. The use of an intraoperative hinging surgical table during MIS-TLIF with bilateral SPOs can effectively lead to an increase in and the maintenance of SL.