Abstract
INTRODUCTION: Lateral Lumbar Interbody Fusion (LLIF), developed by Dr. Luiz Pimenta in 2006, allows access to the spinal column through the psoas major muscle. The technique has numerous advantages, including reduced damage to bone and muscular tissue, indirect decompression, larger implants, and the ability to correct lordosis. However, this technique also presents drawbacks, with the most notable being the risk of spinal pathologies due to indirect injury to the lumbar plexus, albeit with low rates of persistent injuries. Therefore, several groups have proposed classifications to aid in identifying patients at a higher risk of developing neurological deficits. The present work aims to propose a new classification system that relies on the simple observation of easily identifiable key structures to guide decision-making regarding lateral L4-L5 LLIF.
METHODS: Patients aged 18 years or older who underwent preoperative magnetic resonance imaging (MRI) were included. This involved visits to the office between 2022 and 2023 until 50 quality images were obtained. Exclusions were made as follows: anatomical changes in the vertebral body or major psoas muscles that hindered the identification of key structures, or cases with poor-quality MRIs. Each anatomical configuration was categorized as type I, type II, or type III based on consensus among the three observers.
RESULTS: This study included fifty anatomical sites. Seventy percent of the L4-L5 anatomies were classified as type I, 18% were type II, and 12% were type III. None of the type III L4-L5 anatomies were approached using a lateral technique.
CONCLUSION: The proposed classification offers an easy and simple method for assessing the feasibility of a lateral approach to L4-L5.