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Tag: Dr. Christopher Yeung

Posterolateral Selective Endoscopic Discectomy: The YESS Technique

The intervertebral disc, an important supporting structure of the spinal column, is implicated as a major source of low back pain and sciatica.(Ref 1,2) The pathogenesis of disc degeneration and herniation is complex and multifactorial, but clearly outlined and documented by Wolfgang Rauschning’s work illustrating the patho-anatomy of degenerative disc disease and degenerative conditions of the lumbar spine.(Ref 3) Most disc herniations are not the result of an acute event, but an accumulation of several insults to the spine that lead to degeneration, annular tears, and eventual disc herniation.(Ref 4) There are several theories of disc degeneration including mechanical, chemical, agerelated, autoimmune and genetic. Within the mechanical theory, the following types of abnormal loads have been proven experimentally to cause disc injury: torsion (Ref 5), compression (Ref 5,6), repetitive compressive loading in flexion (Ref 7), hyper flexion (Ref 8), and vibration. (Ref 9)

Innovative Techniques in Spine Surgery

Chronic lumbar discogenic pain (CLDP) is a difficult condition to treat, as its pathogenesis is multifactorial and only partially understood. Non-operative therapeutic regimens often fail to achieve sufficient pain relief. Surgical options vary greatly, ranging from minimally invasive treatments such as Intradiscal Electrothermal Therapy to 360° fusion.

Posterolateral Selective Endoscopic Discectomy TM (SED) and radiofrequency (RF) thermal annuloplasty is a minimally invasive treatment option for CLDP. This procedure, developed by the senior author was investigated in 1997 and approved by the IRB at St, Luke’s Medical Center, Phoenix, Arizona.

Posterolateral Transforaminal Selective Endoscopic Discectomy™ and Thermal Annuloplasty

Chronic lumbar discogenic pain (CLDP) impairs the patient’s physical abilities to function within the normal physiologic loading ranges of activities of daily living. The pathogenesis of CLDP is multi-factorial and not well understood. Conservative
therapeutic regimens often fail to achieve sufficient pain relief. Surgical options vary greatly in surgical invasiveness as well as outcome. Definitive surgical treatment is often 360° fusion. The morbidity associated with this approach is significant when considering only 65-80% of patients obtain satisfactory clinical results. This has spawned interest in minimally invasive surgical options like IDET, but results are conflicting.

Advances in Endoscopic Disc and Spine Surgery: Foraminal Approach

Endoscopic spine surgery is evolving rapidly due to improvements in surgical technique, endoscope design, and instrumentation. The current technique expands on the basic features and principles of EKambin’s access to the spine through the triangular zone. A standardized method for foraminal surgery, the Yeung Endoscopic Spine System (YESS)™ (Richard Wolf Surgical Instrument Company, Vernon Hills, Illinois, USA) technique is proposed: (1) A protocol for optimal instrument placement by identifying the skin window, annular window, anatomic disc center, and disc inclination plane through topographical coordinates calculated by lines drawn on the skin from the C-Arm image. Adjustments in the trajectory are made to accommodate individual anatomic considerations and the pathologic disorders to be accessed. (2) Evocative Chromo-Discography™ (Richard Wolf Surgical Instrument Company, Vernon Hills, Illinois, USA). (3) Selective Endoscopic Discectomy™ (Richard Wolf Surgical Instrument Company, Vernon Hills, Illinois, USA). (4) Thermal discoplasty and annuloplasty. (5) Endoscopic foraminoplasty. (6) Accessing the epidural space in the axilla between the traversing and exiting nerve root. (7) Partially resecting the posterior annulus to get beneath the herniated fragment, if needed.

This technique allows access to the epidural space from the lumbar disc as far cephalad as the middle of the vertebral body or approximately 2-3 mm caudally. The foraminal approach is routinely accessible from T-10 to L4-5. L5-S1 can be accessed with special techniques that include foraminoplasty of the lateral facet. Surgical results continue to improve, consistent with refinement of indications and techniques for specific conditions treatable by this endoscopic method.

Minimally Invasive Techniques for the Management of Lumbar Disc Herniation

Minimally invasive surgery is the current trend for all types of surgery, especially in the spine, where surgical approaches and procedures are still considered by many as a treatment of last resort unless there is evidence of progressive neurologic involvement. In part, the hesitation to consider surgery is due to concerns over the morbidity of traditional spinal surgery, which damages muscle during the approach to the spine. Minimally invasive discectomy is considered desirable by most patients and by many surgeons. For lumbar disc herniation, however, the degree of minimal invasiveness varies widely between surgeons. The most common modern adaptation of a minimally invasive technique is described as a microlumbar discectom

Endoscopic Identification and Treating the Pain Generators in the Lumbar Spine that Escape Detection by Traditional Imaging Studies

The ability to identify and treat pain generators in the lumbar spine is helped by incorporating diagnostic and therapeutic injections, followed by visualizing the pain generator with an endoscope. Although improvements in imaging are getting very sophisticated, visualization of the source of the pain generators is currently only possible with an endoscope. This has opened the door to more options for cost effective surgical treatment in staged manner by treating the pain source.

Selective Endoscopic Lumbar Discectomy (SED™) and Thermal Annuloplasty for Discogenic Back Pain, Disc Herniations and Sciatica in High Performance Athletes and Physically Active Patients

Introduction: 25 years experience in transforaminal endoscopic surgery from a personal and spine group database is reviewed relating to treatment of discogenic pain and disc herniations.

Method: An ongoing IRB study approved in 1997 resulted in a continued study using a transforaminal endoscopic procedure with an endoscope designed for intradiscal transforaminal decompression of painful traumatic and degenerative conditions of the lumbar spine. The system developed was named the Yeung Endoscopic Spine System (YESS™) by Richard Wolf Surgical Instrument Company Vernon Hills, Illinois. The technique accompanying the system has evolved over 25 years as indications were stratified over multiple studies published in peer reviewed journals that resulted in the indications promoted and validated known as the YESS™ technique. Results of the treatment of discogenic pain and disc protrusions are provided in this summary. The vast majority of the data was generated by one surgeon (ATY) but since 2001, the co-author (CAY) and 2 other spine surgeons of the spine group practice contributed to the maintained database.

Results: A summary of the stratified results are listed in the text of the article. Indications and results provide validation of the conclusion that SED™ is the least invasive technique for surgical treatment of disc herniations, especially if treated early in the disease process.

Conclusion: With evolving techniques that continue to advance, such as diagnostic and therapeutic injections using the same trajectories to target the patho-anatomy of the pain generator, indications can be further stratified for patient selection to the extent that 90% prediction of transforaminal surgical decompression results using the “YESS” technique can be “warranteed” to improve the painful condition once the learning curve is reached and stabilized for each individual surgeon. Each surgeon stratifies their patient selection by depending on their individual patient selection criteria.

Lessons Learned Using Local Anesthesia for Minimally Invasive Endoscopic Spine Surgery

Background/purpose: Operating under local anesthesia allows the patient to respond and provide feedback during surgery that is invaluable for patient safety and for the assessment of the pain generators and ultimately understanding of the source of pain that the surgeon is targeting. Over 10,000 case studies make up the database for information gleaned from patients reporting the pain experienced and relieved during translaminar and transforaminal endoscopic decompression.

Method: The patient is provided mild sedation with versed and fentanyl unless no sedation is requested. Patients requesting no sedation are usually anesthesiologists and other spine surgeons who opt for decompressive surgery, but wanted some measure of surgical participation and control. The anesthesiologist titrates the patient with 1-2 cc of fentanyl and versed pre-op with titration during surgery. The average total amount is 4-5 cc for most procedures. 1% lidocaine is utilized for the local anesthetic. An average of 10-20 cc is used for local anesthesia, titrated as needed during surgery.

Results: The results of decompression can be predicted by a combination of pain relief reported during, immediately after, and augmented by visualization of the targeted patho-anatomy. Such visualized pathology visualized includes annular tears, decompressed spinal nerves, and visualization of the axilla between the traversing and exiting nerve.

Conclusion: Observations provides level 5 EBM (Expert opinion) for surgical intervention. Evidence based medicine usually starts with level 5 “expert” opinions. With the ability to evoke pain in conscious surgical patients, with endoscopic images of the patho-anatomy that correlates evoked pain production with subsequent pain resolution following visualized endoscopic decompression. Along with comparison of pre-and post op images, a new and different and level of EBM may emerge and need to be considered in addition to the traditional Levels 1-5 EBM guidelines.

Endoscopic Surgery of the Spine as a Multi-Disciplinary Subspecialty for Appropriately Trained, and Experienced Providers

Introduction: Endoscopic spine surgery has attracted both surgeons and nonsurgeons in increasing numbers as endoscopic spine systems, a variety of spine endoscopes, and new and evolving surgical instrumentation are developed. The procedure, using fluoroscopically guided percutaneous techniques, are getting more standard, easier, safer, readily reproducible, and more cost effective. It has also been an avenue for surgeons and a few appropriately trained and certified non-surgeons to participate in a minimally invasive, procedure oriented health care delivery platform that provides cost effective results after failure of nonsurgical methods. Such a multidisciplinary team has been established at the University of New Mexico through a donation to the University by the first author.

Discussion: Asia, especially China and Korea, has seen adoption of endoscopic spine surgery grow exponentially in the past few years, recognizing that endoscopic spine surgery may be the answer to delivering cost effective spine care to their working and aging population. Two basic methods are the mainstay of current endoscopic techniques. The least invasive techniques in the lumbar spine are transforaminal, but translaminar endoscopic approaches are better accepted and easier for endoscopic surgeons to grasp.

Conclusion: Endoscopic spine surgery has great promise in countries with looking for cost effective delivery of health care to its population. Endoscopic surgery is the least minimally invasive surgical platform that will facilitate a move away from fusion as a first line of surgical treatment, delaying or eliminating fusion for patients who may have indications for decompression and fusion, but do well with an earlier and staged procedure that will mitigate the need for open decompression and fusion by 75%, derived by large individual and group databases known to this author.

Microtherapy in Low Back Pain

Experimental in vivo stimulation of the annulus fibrosus of an intervertebral disc produced back pain, and the term “discogenic pain” was coined to establish the association between annulus stimulation and the subjective pain perception. Histologically the end organ neural sensors are located in the outer layers of the annulus, epiannular surface, and the juxta endplate region. Nucleus pulposus and its metabolic byproducts are known contact irritants to the nerve tissues and are known to reduce their membrane excitation threshold. There is no direct contact between the neural end sensors and the intradiscal irritants in an intact disc.

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