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Algos
Thoracic Dekompressor Discectomy
Techniques
| Thoracic discectomy at T7-8 for a moderate contained disc prolapse is hazardous regardless of the approach. Many neurosurgeons will not attempt such due to the risk of paralysis. The transcostal approach, posterior approach, posteriolateral endoscopic approach, and more recently, thoracoscopic approaches have all been successfully applied to the thoracic disc. The latter technique has an excellent success rate in the hands of masters of surgery such as Curtis Dickman at the Barrow Institute, where I refer all cases of thoracic HNP. However, recently we encountered a patient who adamantly refused open or thoracoscopic techniques, desiring a minimally invasive approach. After the substantial risks were explained to her and all conservative measures including transforaminal ESI were exhausted, the T7-8 thoracic discectomy was performed. Because of the difficult anatomy at that level, a 22ga seeker needle was placed into the disc. Initially, an attempt was made to traverse the costal-transverse facet, but the articulation did not permit such penetration. Therefore, an approach superior to the transverse process was chosen, approximately 7 degrees cephalocaudad and 40 degrees from the sagittal plane. Once the disc was cannulated in the posterior third, it was apparent the bend in the needle would require a different trajectory for the 1.5mm Stryker needle that must be straight to ensure appropriate operation of the Dekompressor. Therefore the trajectory was chosen to match the distal 2cm of the seeker needle, which placed the Stryker needle entry point 1.5cm cephalad to that of the seeker needle. The following sequence of pictures demonstrates the advancement under frequent AP and lateral views. Since the cord lies at the medial pedicular line, advancement into the posterior annulus on lateral view was obligatory prior to the needle tip reaching the medial pedicular line in the AP view. Small advancements were made with frequent fluoroscopic visualization. Once the needle was in the posterior annulus, further advancement was made in the lateral fluoroscopic view, then the Dekompressor was attached and discectomy was performed with primarily lateral fluoroscopic views used during needle retraction. Because of the risk of needle dislodgement, the technique of thoracic percutaneous discectomy would ideally be performed with a static needle technique such as a laser technique or coblation nucleoplasty. Nevertheless the procedure was completed successfully without complications. BECAUSE OF THE HIGH RISKS OF SERIOUS COMPLICATIONS, IT IS SUGGESTED ONLY THE MOST EXPERIENCED PHYSICIANS PERFORM THIS TECHNIQUE AND ONLY WHEN OTHER SURGICAL OPTIONS ARE UNAVAILABLE. |
