Thoracic microendoscopic discectomy - A human cadaver study

Study Design. Feasibility analysis of percutaneous posterolateral thoracic microendoscopic discectomy in a human cadaver model. Objective. To describe a new, minimally invasive, posterolateral approach to the thoracic spine for the treatment of disc herniations. Summary of Background. Thoracoscopic discectomy offers surgeons direct ventral access to thoracic disc herniations but requires entry into the chest. Many surgeons favor a posterolateral approach to the thoracic spine, thereby avoiding morbidity associated with entry into the thoracic cavity. By adapting minimal access surgical techniques to the thoracic spine, effective treatment of thoracic disc herniations should be possible and may help expedite recovery. Methods. Two cadaveric human torsos were used. Using simple adaptations of our standard lumbar microendoscopic discectomy technique, endoscopic discectomies were performed throughout the mid and lower thoracic spine. Operative time was recorded. The extent of the discectomy as well as the extent of bony removal was evaluated using computed tomography myelography. Results. Nine discectomies were performed in two cadaveric specimens, from T5-T6-T9-T10. Operative times ranged from 46 to 77 minutes (mean 60 minutes). The procedure required removing 3.4 mm (+/- 1.9 mm) of the ipsilateral facet, which amounted to 35.4% (+/- 17.5%) of the facet complex. Canal decompression averaged 73.5% (+/- 7.9%). Conclusions. Thoracic microendoscopic discectomy allows for a posterolateral approach to thoracic disc herniation without entry into the chest cavity that consistently gives access to the majority of the canal while requiring only a minimal amount of bone removal. This technique provides an approach angle similar to that obtained with other posterolateral discectomy techniques while limiting the morbidity associated with exposure.