Experimental Laparoscopic and Thoracoscopic Discectomy and Instrumented Spinal Fusion. A Feasibility Study Using a Porcine Model

Abstract

To explore the safety and the effectiveness of laparoscopic and thoracoscopic spinal surgery, an acute/non-survival animal trial was performed in 5 pigs using rigid and flexible endoscopes, flouroscopy, a holmium-YAG laser, and prototype instruments and implants. Our study aimed to approach the intervertebral disc space and spinal canal using laparoscopic and thoracoscopic techniques and to explore the potential and limits for endoscopic anterior spinal decompression and fusion. In a lateral recumbency access was provided to the anterolateral aspect of the lumbar spine from L1/2 to L7/S1, the thoracic spine was accessible from T2/3 to the diaphragmatic insertion. Complete disc space emptying with penetration into the spinal canal could be performed, epidural bleeding could be controlled by a hemostatic sponge, however bleeding restricted visualization for further endoscopic manipulation in the spinal canal. Intervertebral fusion was accomplished at T6/7, L4/5 and L7/S1 using small fragment plates with 3.5 mm screws and iliac bone grafts or prototype carbon fiber cages. On post mortem examination we found no dural tears and no nerve root damage, all animals had stabilized fusion sites and good implant position. We conclude that minimally invasive thoracoscopic and laparoscopic approaches to the spine are feasible and safe to perform disc decompression and implant placement for spinal fusion. In addition to currently performed laparoscopic interbody fusion, also plate fixation to reestablish lordosis of the lumbar spine is feasible at least in the porcine model. Careful disc decompression must be performed prior to implant introduction to prevent iatrogenic disc protrusion and spinal cord or nerve root compression. However, further surgical exploration of the spinal canal using these techniques does not provide adequate visualization of epidural spaces and therefore must be regarded as unsafe.

Thoracoscopic Intradiscal Spine Fusion Using a Minimally Invasive Gene-Therapy Technique

“…Although the posterior intertransverse process fusion rate in the rabbit model appears to be similar to that in humans, the rate in the porcine model has never been compared with that in humans, to our knowledge. On the other hand, the porcine model has been widely utilized for studies on endoscopic procedures because of its anatomic similarity to humans [12][13][14] . While our results suggest the eventual possibility of similar results in humans, there are numerous technical and practical hurdles that must first be overcome.…”

The influence of intervertebral disc tissue on anterior spinal interbody fusion: an experimental study on pigs

“…The pig model has often been used for laparoscopic spine surgery training and experimental studies [11,12]. In the present study the pig model was employed because of the availability and size suitability of the pigs for the cages.…”

Laparoscopic lumbar spine surgery

“…The usefulness of porcine models has been described [9,13,18], and this appears to be an optimal simulation of human laparoscopy from an anatomical and surgical point of view. A learning curve has been demonstrated [16], and this must be factored in when beginning this type of surgery, and in consenting patients for these procedures.…”