Journal of Spine

In-vivo Endoscopic Visualization of Pain Generators in the Lumbar Spine

Abstract

Anthony T Yeung

Introduction: Traditional interventional pain management only provides temporary relief that depend on the patient’s natural healing to mitigate pain. Visualizing the patho-anatomy with an endoscope targeting the pathoanatomy by interventional needle trajectories, however, has opened the door for surgical decompression and ablation of the pain generators. Endoscopic spine surgery is effective using mobile cannulas to target the pain source facilitated by surgical visualization and decompression and ablation using an endoscope. New instrumentation, techniques, specially configured endoscopes, access cannulas, RF and laser modalities all facilitate effective surgical treatment of the pain generator. While traditional translaminar surgical approaches provide open access to spinal pathology, there are conditions better suited for an endoscopic approach, especially when the surgeon can add intradiscal therapy using the transforaminal or translaminar approach. When a surgeon combines interventional techniques with endoscopic visualization, additional effective steps in the treatment algorithm are available. The purpose of this paper is to demonstrate that the physiology of pain can be visualized, and treated surgically as the path-anatomy of a pain generator.

Materials and method: In endoscopic transforaminal surgery, the Yeung Endoscopic Spine SurgeryTM (YESSTM) technique, is utilized: 1. Needle and cannula placement for optimal instrument placement is calculated from skin marking drawn on the skin from the PA and Lateral C-arm image. A similar needle trajectory is utilized for diagnostic and therapeutic injections as a diagnostic precursor that helps predict the success of transforaminal endoscopic surgical intervention. 2. Injection of non-ionic radio-opaque contrast will create a foraminal epidural gram and produce epidural patterns that outline foraminal patho-anatomy such as HNP; central and lateral recess stenosis, and other pathologies from the epiduralgram pattern. 3. Evocative chromo-discographyTM is performed to provide a normal or abnormal discogram pattern that helps correlate the patho-anatomy of discogenic pain. Disc and foraminal decompression is aided by vital tissue staining. 5. Endoscopic foraminoplasty decompresses the lateral recess and visualizes the exiting and traversing nerve in the axilla containing the Dorsal Root Ganglion (DRG), In addition, other anomalous path-anatomy not suspected or identified by traditional imaging can be visualized with the endoscope. 6. Surgical exploration of the epidural space. 7. Probe the “hidden zone” of Mac Nab under local anesthesia with a capability for the patient to provide back to the surgeon during surgery while mildly sedated or without sedation under local anesthesia. 8. Using a biportal or multiple portal techniques for out-side in or inside-out removal of extruded and sequestered nucleus pulposus and other patho-anatomy. 9. Dorsal and foraminal visualized rhizotomy of the branches of the dorsal ramus to denervate the facet joint. A database of over 10,000 surgical cases utilizing jpeg and MP4 video imaging illustrate the painful conditions most suitable and also possible with endoscopic surgery.

Results: The transforaminal endoscopic technique will allow surgical access to the lumbar spine for treatment of a wide spectrum of painful degenerative conditions. There are, moreover, conditions where the endoscopic foraminal approach has advantages over traditional surgical approaches. These conditions are: 1. Discitis 2. Far lateral foraminal and extraforaminal HNP, especially at L5-S1, 3. Upper lumbar HNP 4. Lateral foraminal stenosis. 5. Discogenic pain from toxic annular tears 6. Visualizing the pain generators responsible for failed back surgery syndrome (FBSS). 7. When anomalous nerves such as furcal nerves are visualized, judgment must be used to determine whether the nerves can be avoided or ablated. Avoiding the nerves my cause failed back surgery syndrome by failing to remove the source of pain in the “hidden zone”, or ablation can resolve the cause of pain from these branches of spinal nerves, also described as conjoined nerves. If the nerve does not hurt on probing or thermal stimulation, it is usually safe to ablate the nerve, with the risk of temporary dysesthesia requiring time to resolve, or the use of transforaminal steroid blocks and sympathetic blocks. Repeat surgical attempts to further decompress the foramen is discouraged as the symptoms and any effect of weakness may worsen or become permanent.

Conclusion: New surgical skills are needed for spine surgeons to incorporate endoscopic spine surgery in their practice. Incorporating interventional pain management techniques as a surgical as well, and not just as a diagnostic procedure confirmed by the results of rational treatment of the patho-anatomy under local anesthesia helps marry the basic science of surgical micro-anatomy with surgical results. This provides additional clinical information that facilitates surgical intervention. New surgical procedures focusing on intradiscal therapy, disc augmentation, biologics, annular modulation, and tissue neuromodulation are all well suited for the minimally invasive approach. Endoscopic foraminal access to the lumbar spine will open the door to for true minimally invasive access to the lumbar spine without affecting and destabilizing the dorsal muscle column. Formal training or mentorship is needed to make this technology mainstream. New evolving technology facilitated by robotics and biologics will help evolve this procedure in the near future.