Ex Vivo Porcine Models Are Valid for Testing and Training Microsurgical Lumbar Decompression Techniques.

Abstract

Spinal surgeries are the leading causes for patient settlement issues. Recent European Medical Device Regulations aims to reduce complications by enforcing that surgical tools are validated before clinical use. Human cadavers are favored in preclinical use, but due to anatomic variance, decay, and scarce supply, alternative synthetic and animal models are used. This study evaluates the fidelity and validity of porcine models in training and assessment of microsurgical decompressive techniques in the lumbar spine. Anatomic dimensions of 10 human and 5 young pig spines were assessed from computed tomography images. Novel "en bloc" fresh-frozen ex vivo porcine model tissues' fidelity and validity for decompressive surgery was evaluated by 3 expert neurosurgeons, in comparison with other models. The pigs' anatomic dimensions were on average 11% smaller than in humans. The pigs' L4-L5 was most alike humans, and the highest similarity was in lamina and spinous process widths, and the skin to posterior longitudinal ligament distance. Dimensional variability was higher in humans (F = 19.06-0.56, P < 0.05). The pigs' tissues were felt as good as living patients and better than cadavers for skin, fascia, bone, facets, ligamentum flavum, and dura, but poor for vessels (experts' intraclass correlation coefficient = 0.696-0.903). The pig models' validity for assessing drills' adverse features (friction, jitter, heating, and soft tissue trauma) was reported to be unanimously excellent. Pigs are representative for assessing microsurgical decompression techniques in the lower lumbar spine. The novel "en bloc" pig model can be an asset for industries and clinicians during assessment and training of new spinal techniques.