Predictors of the need for rib resection in minimally invasive retroperitoneal approach for oblique lateral interbody fusion at upper lumbar spine (L1-2 and L2-3)

Background: This study aimed to identify factors that can predict the need for rib resection in a mini-mally invasive, oblique retroperitoneal approach for upper lumbar interbody fusion (OLIF at L1-3) using modern tubular retractors. Methods: Eighty-six patients, who underwent L1-2 and/or L2-3 OLIF at a single institution, were included. Decision for rib resection was made through intraoperative fluoroscopic view (true lateral view of the desired level). Patients were divided into two groups according to rib resection (rib resection and non-rib resection groups). Baseline demographics, surgical and radiographic data, including coronal/ sagittal spinopelvic parameters and perioperative complications, were compared between the groups. Logistic regression analysis was performed to identify the factors predicting the need for rib resection. Results: The study cohort comprised 31 patients in the rib resection group and 55 patients in the non-rib resection group. There was no significant inter-group difference in terms of the baseline demographics. A total of 79% patients undergoing the two-level (both L1-2 and L2-3) procedures were rib-resected, while 81.6% of the patients undergoing the L2-3 level alone were not rib-resected. Endplate injuries occurred more commonly in the non-rib resection group (3% vs. 14%). Pleural laceration was observed in 6% of the patients in the rib resection group. The mean T10-L2 kyphosis was larger in the rib resection group than in the non-rib resection group (14.9 & DEG; vs. 6.6 & DEG;, P 1/4 0.031). Multivariate logistic regression analysis iden-tified the following independent predictors of the need for rib resection: an L1-2 inclusive procedure; T10-L2 kyphosis > 15.9 & DEG;; and the apex of the coronal curve located above L2. Conclusion: : The need for rib resection should be expected when performing L1-2 inclusive procedure. Even in the L2-3 alone case, aggressive decision-making for intraoperative rib resection might be required for an appropriate tubular retractor position, especially for patients with thoracolumbar kyphosis and apex vertebra of the major coronal curve located above L2. & COPY; 2022 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.