P124. The lordosing effect of the prone transpsoas technique: preliminary results of a multicenter experience

Abstract

BACKGROUND CONTEXT The lateral lumbar interbody fusion (LLIF) is a proven and effective technique to treat a vast range of lumbar disorders. Nevertheless, the LLIF is also burdened by some problems, such as postoperative neurological deficits, small segmental index level lordosis, and the frequent necessity to reposition the patient to instrument posteriorly. A new approach to LLIF was devised to solve or reduce some of the drawbacks associated with the lateral approach. Its main difference from other lateral approaches is in positioning the patient in the prone position, which might lead to improved intradiscal lordosis and overall sagittal alignment. PURPOSE Report early radiographic results from LLIF using the prone transpsoas technique (PTP). STUDY DESIGN/SETTING Retrospective, non-comparative, non-randomized analysis of a prospectively collected database from four separate centers. PATIENT SAMPLE Patients include those who underwent PTP at four participating centers. Inclusion criteria: Signed consent, underwent any number of PTP levels, with complete perioperative radiological outcomes. Exclusion: Incomplete radiological data, procedures that included anterior column release (ACR) or that otherwise had a resected anterior longitudinal ligament. OUTCOME MEASURES Preoperative and postoperative pelvic incidence (PI), pelvic tilt (PT), lumbar lordosis (LL: L1-S1), pelvic mismatch (PI-LL), and index-level segmental lordosis. METHODS Patient characteristics were collected through a retrospective analysis of radiological data and measured with special computer software. For continuous variables, mean and 95% confidence were reported, and for dichotomous variables, counts of values and percentages were reported. Student's T-test was performed to compare continuous variables and Fisher's Exact Test was used to compare dichotomous variables. Calculations were performed using Excel. RESULTS Forty (40) patients undergoing PTP at 59 levels were included in the study. Twenty-nine (29) underwent single-level, eight underwent two-level, three underwent three-level, and one underwent four-level PTP. Mean index-level segmental lordosis increased from 7,2° (± 7.3; 95% CI 5,3-9,1) to 14,0° (± 6,8; 95% CI 12,2 – 15,7) (p CONCLUSIONS The LLIF prone transpsoas technique is feasible and relies on prone patient positioning, an advantage for improving lordosis and enabling the surgeon to supplement with posterior procedures. Preliminary results show significant lordosis improvement even without anterior longitudinal ligament release. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.