Radiological outcomes of Lateral Lumbar Interbody Fusion (LIF) in Adult Spinal Deformity – A Systematic Review

Background Data: Adult spinal deformity (ASD) needing surgical treatment is often seen in the aging population. Radiological goals for ASD surgery have been standardized to achieve a good functional outcome. Lesser complication rates and blood loss have made MIS surgeries more popular in the current day. Trans-psoas / Pre-psoas Lateral Lumbar Interbody Fusion (LIF) has been the cornerstone of MIS surgeries for ASD. The corrective potential of conventional MIS surgeries was limited, owing to which various modifications have been described. Despite the demonstration of good clinical outcomes by various studies employing different surgical techniques, cumulative analysis of the radiological outcome of the various modifications of LIF is poorly discussed in the literature. A recommendation of an ideal MIS technique based on the type and magnitude of ASD is also lacking. Purpose: We aim to perform a qualitative systematic review of the radiological outcomes of various modifications of LIF surgeries for ASD and to decipher a treatment algorithm based on the type and severity of ASD with existing literature. Study design: Systematic review. Patients and Methods: A systematic search of two electronic databases (PubMed & Google Scholar) from its inception till December 2020 was done independently by 3 different authors. Relevant keywords and MeSH terms were used to identify articles and further filtered by applying appropriate selection criteria. Results: A total of 171 articles were selected for abstract screening, followed by full-text screening. After applying the selection criteria, 28 articles were selected for the systematic review. The methodology and radiological parameters of each study were analyzed qualitatively, and the inferences in regards to the radiological outcomes were validated. Conclusion: Circumferential MIS (cMIS) seems to be adequate in milder forms of ASD, while hybrid surgeries may be needed in higher magnitude deformities. Addressing the L5-S1 junction using LIF and anterior column realignment (ACR) are useful tools to correct more severe deformities. (2020ESJ223)