A refined porcine lumbar spinal cord injury model facilitating postoperative care

Background Pigs exhibit strong anatomical and neurological similarities to humans, making them valuable translational models for spinal cord injury (SCI) research. While most porcine SCI models target thoracic levels, these are often associated with significant postoperative management challenges, particularly related to urinary function. Methods To address these limitations, we characterized a refined lumbar SCI model targeting the L3 vertebral level in pigs, based on comparative anatomy and veterinary data. SCI was induced using a contusion-compression paradigm under per-operative C-arm fluoroscopic guidance. Functional assessments were conducted at three time points: 2 days pre-injury, and 2 and 14 days post-injury. These included general activity monitoring, qualitative evaluation using the Porcine Thoracic Injury Behaviour Scale (PTIBS), and quantitative gait analysis using inertial measurement units and electro-goniometers. Animals were euthanized 3 weeks post-injury for ex vivo 7T MRI and histological analyses. Results All animals developed complete paraplegia at 2 days post-injury (PTIBS = 1), progressing to severe but partial recovery by day 14, with a significant decrease in PTIBS score (-6.5 ± 0.3) and hip extension (-36.1%). Importantly, all animals exhibited immediate and persistent urinary incontinence, avoiding the need for catheterization. MRI and histological analyses confirmed consistent and reproducible lesions at the injury site, affecting both white and grey matter. Conclusions This refined lumbar SCI model induces reproducible motor deficits associated with urinary incontinence, facilitating postoperative management while preserving translational relevance. It provides a practical platform for investigating functional recovery and testing therapeutic strategies in SCI.