What is SED/YESS?
Selective Endoscopic Discectomy™ (SED™) is a minimally invasive spine surgery technique that utilizes an endoscope to treat herniated, protruded, extruded, or degenerative discs that are a contributing factor to leg and back pain. The endoscope allows the surgeon to use a “keyhole” incision to access the herniated disc. Muscle and tissue are dilated rather than being cut when accessing the disc. This leads to less tissue destruction, less postoperative pain, quicker recovery times, earlier rehabilitation, and avoidance of general anesthesia. The excellent visualization via the endoscope permits the surgeon to selectively remove a portion of the herniated nucleus pulposus that is contributing to the patients’ leg and back pain.
Thermal annuloplasty is an adjunctive procedure that uses bipolar electro-thermal energy (radiofrequency and/or laser) to ablate or depopulate the sensitized pain nociceptors in the annulus, ablate any inflammatory/grannualtion tissue that has grown into the annulus, and to shrink and tighten the stretched or torn collagen fibers of the annulus. The annulus is the outer portion of the disc and is composed of many concentric layers that are arranged similarly to the plies of a radial tire. Thus, the weakened annulus or defect left by the disc herniation is contracted and possibly sealed from within the disc.
This combination procedure and the endoscopic system used to perform the unique procedure is pioneered and developed by Dr Anthony Yeung, with instruments developed with the Richard Wolf Instrument Company (YESS – Yeung Endoscopic Spine Surgery system). This state of the art technique is an evolution from the technique originally described by Parviz Kambin called Arthroscopic Microdiscectomy (AMD).
The technique has been validated with a study monitored by the Institutional Review Board at St. Luke’s Medical Center, Phoenix. Dr Yeung’s procedure is published in peer reviewed literature and a current topic of interest in national and international spine meetings. (See Dr Yeung's CV and speaking schedule.)
There are other electro-thermal techniques utilized for painful, bulging degenerative discs and annular tears called IDET and Nucleoplasty/Coblation. SED™ and thermal annuloplasty, however, is NOT the same. SED™ is different because it is a visualized endoscopic surgical method (like knee arthroscopy) that is designed to visualize the patho-anatomy of the disc, spinal canal, and the adjacent nerves. These other percutaneous procedures are only fluoroscopically guided and are termed “blind” procedures. Consequently, SED™ can be used for pain caused by contained or non-contained (extruded) disc herniations, and sometimes works as well for discogenic back pain that is not responsive to non-operative treatment. (See FAQ's for more information about the differences.)
Patients who are otherwise destined for fusion may have a minimally invasive alternative for pain relief without fusion in selected patients. Dr Yeung is currently teaching the FDA approved procedure to other surgeons, and it is becoming available in other states and countries as the surgeons trained by Dr Yeung are converting from the open to the endoscopic technique. In Arizona, it is currently being performed only in Phoenix at the Squaw Peak Surgical Facility that Dr Yeung operates.
About the procedure
Surgery time is approximately 15-30 minutes per disc. A small ¼ inch incision is made on the back to the side of the spine. Entry point is precisely calculated by fluoroscopic intraoperative measurements using a technique designed by Dr Yeung. Sedation and local anesthesia is provided. The anesthetic will allow the patient to be comfortable during the procedure but will leave enough feeling in the nerves so the patient can actually tell when the nerve is being stimulated or when pressure is taken away from the nerve. The nerves may also be monitored during the procedure with continuous EMG and nerve conduction measurements so that changes are carefully monitored.
The instrument placement is performed under fluoroscopic guidance. A conical probe (obturator) with a side hole for palpating structures and for anesthetizing painful structures is used to dilate a path to the disc. After determining that the probe is in the safe triangular zone between the traversing and exiting spinal nerves, the disc is entered either by bluntly fenestrating the annular fibers with the probe or cutting the annulus with a trephine. If there is an unusual amount of pain with the docking of the blunt probe on the annulus, the surgeon can opt to visualize the outer aspect of he disc before entering the disc. Anomalous nerves and branches of spinal and automonic nerves have been visualized and documented as contributing causes of back and leg pain that are currently not recognized by traditional surgeons. This area in the foraminal and extra-foraminal zone has been termed the “hidden zone” by surgeons Ian MacNab and John McCullouch. The presence of these anomalous nerves, and the ingrowth of nerves from an inflammatory membrane that forms over the sensitive disc annulus is responsible for pain that is out of proportion to what the Mri shows. This phenomenon is not yet completely understood, but good results have been obtained by identification and ablation of these nerves, and by elimination of the condition causing the inflammation.
The procedure proceeds by a cannula being passed over the blunt obturator followed by insertion of the endoscope and operating instruments. The two spinal nerves are protected by the cannula and only thepart of the disc needing surgery will be exposed to the operating instruments. The endoscope is inserted into the cannula and degenerated nucleus pulposus is visualized and selectively removed from the herniation site in the posterior portion of the disc. When treating annular tears a small amount of nuclear tissue is removed from underneath the tear. Often, some of this nuclear tissue is seen interposed within the tear preventing it from healing.
The advanced endoscope has integrated multichannel irrigation channels allowing for continuous cool saline irrigation similar to knee arthroscopy. A radio frequency electrode is used to help control bleeding, shrink the disc tissue or shrink the annulus, and ablate ingrown inflammatory/granulation tissue. Heat from the radio frequency probe may also help depopulate and ablate the pain fibers in the annulus.
Occasionally chymopapain may be recommended to assist in the removal of disc tissue when the fragment is large and narrow, has migrated beyond the reach of instruments, or to decrease the chance of recurrence. Using Chymopapain is similar to using a solvent to help remove rubbery and hardened pieces of gum. Chymopapain can also alter the remaining nucleus pulposus by making it less chemically or mechanically irritating to the adjacent sensitized spinal nerves.
Sometimes a "biportal" approach is needed which adds one small incision on both sides of the spine. This allows the surgeon to visualize his instruments inside the disc when the size of the instrument is too large to use within the operating scope.
Sometimes disc fragments are identified outside the confines of the annulus. If the fragment cannot be completely extracted with the endoscopic instruments, a subsequent surgical procedure using the traditional posterior approach may be necessary. Occasionally, a second endoscopic procedure is recommended when a missed fragment is left behind. This happens about 10% of the time if there is a sequestered fragment. Advanced endoscopic techniques will also allow the experienced endoscopic spine surgeon the ability to routinely visualize the exiting nerve root, a nerve that is rarely visualized by traditional spine surgeons when they remove herniated discs. Lateral or foraminal stenosis contributing to back pain and can also be documented and surgically treated at the same time.
The procedure is performed in an outpatient setting. No hospitalization is needed.
Expected results
The goal of this procedure is to provide relief of leg pain and prevent further neurologic injury. Back pain is frequently relieved, but may persist because of arthritis or other sources of back pain not coming from the disc. Success rates are similar to the published results of standard microscopic discectomy, but with less recovery time and quicker rehabilitation due to the more minimally invasive nature of SED™.
There may be some discomfort in the surgical area. Other light activity is resumed on the evening of surgery and is gradually increased at home. Leg pain may subside immediately, or after several months. Your pre-operative pain may temporarily increase or change in character. On infrequent instances, if your pain persists, or if it returns, further tests may be needed to look for other causes of your pain, so it is imperative that you keep in contact with Dr Yeung after your surgery for up to a year , then on a yearly basis.
Follow-up in the office will occur days, or 1 to 2 weeks after surgery depending on the patient’s location and situation. One can expect to return to work in 1 to 4 weeks (or earlier if ready) depending on the job demands. Out-of- town patients are usually seen 1-2 days postoperatively to determine whether they can travel home the next day.
Potential Complications
Although complications are rare, they can occur. Complications are similar to traditional surgery, which may include death and paralysis. Nerve injury, dysesthesia, complex regional pain syndrome, dural tears, bowel injury, psoas hematoma, epidural hematoma, and segmental instability are complications have occurred and may require additional treatment or surgery to resolve. You may have anomalous nerves in the foramen that can cause increased pain before your original pain subsides. Because we are dealing with a deteriorating spine, the degenerative and aging process cannot be reversed, so one of the goals is to make the degenerative process less painful, but it will never-the-less still progress or accelerate. Your pain, therefore, in severe degeneration, may persist or return to its pre-operative level and in some cases may even worsen. In that case, alternatives such as disc replacement or fusion is still possible.
One unavoidable consequence after any surgery is scar tissue. Although it is minimized in Selective Endoscopic Discectomy™, its presence is variable and may be responsible for residual leg pain. The overall serious complication rate causing permanent residual is less than 1-2%.
The most common side effect that may not be deemed a complication is the feeling of numbness or hypersensitivity (dysesthesia) in your leg after surgery. It can occur immediately after surgery or days and weeks later. Dysesthesia cannot be completely eliminated and its causes are still not completely understood. It is sometimes explained by a nerve that has been numb for a long time from prolonged pressure suddenly becoming decompressed and receiving new blood supply. It is also similar to the "phantom limb" phenomenon experienced by some patients who had a limb amputated. Since one of the goals of surgery is to depopulate and ablate the sensitized nerves in the disc to relieve pain, the process of thermal modulation may cause dysesthesia. The actual cause is still speculative, as it can occur even when neuromonitoring does not demonstrate any irritation of the nerve during surgery. When this occurs, it is almost always temporary, but may need nerve blocks and medication to desensitize the nerves.
When your disc becomes hypersensitive to everyday stresses, this can be due to new nerves and blood vessels growing into your degenerating discs. An inflammatory membrane forms, along with a process called angiogenesis and neurogenesis. Ablation of this inflammatiory membrane is associated with an increased incidence of dysesthesia, but ablation also increases the chance of pain relief. There are also anomalous nerve branches that connect spinal nerves to each other and form in the fat over the annulus. These nerves are called furcal or "forked" nerves, and not usually seen by traditional spine surgeon, but can be visualized endoscopically in the area of the foramen and in the triangular zone where the endoscopic instruments must pass. Removal of some of these tiny nerves that are not part of the normal nerve may not be able to be avoided, and can even be found in the surgical specimen.
Communication is very important. Your decision to have SED™ must be made only after you assure yourself that you are fully informed, and any concerns you have must be brought to your surgeon's attention and discussed in detail to your satisfaction. Because this is a new procedure, non-endoscopic surgeons and endoscopic surgeons not familiar with Dr Yeung’s technique may give you a different opinion that is based on their own experience or with their familiarity with the literature. Some surgeons unfamiliar with the technique may be even argue against it. Any concerns brought up by a second opinion should be brought to Dr Yeung’s attention so he can communicate with your surgeon if you or he desires. Dr Yeung believes you should have the freedom to make an informed shared decision about your care. After you have made the decision to have SED™, if you have any problems related to your surgery, it is imperative that you call our office at (602) 944-2900 and notify us about any problems. Most complications can be resolved with proper intervention, but unwarranted delay may jeopardize your surgical result.
Preoperative preparation
Plain x-rays of your spine may be necessary at the time of your preoperative appointments. This will help with pre-operative planning.
Blood work and urinalysis, medical clearance, and psychiatric evaluation may be necessary in certain circumstances if your medical history dictates the need. Stop all aspirin, non-steroidal anti-inflammatory medications, and alcohol two weeks prior to the procedure or as directed by the preoperative nurse. If you need to continue your medication, ask Dr Yeung about the medication. If you need the anti-coagulant effect of aspirin for a heart condition or thrombophlebitis, please inform Dr Yeung. Report any concerns about your health that may affect the decision for surgery. Do not eat or drink anything after midnight or eight hours before the procedure. This includes water, coffee, and juice. If you take medication regularly, ask Dr. Yeung whether you can take the medication with a sip of water.Postoperative instructions
A more detailed instructional hand out is provided for post-op surgical patients
Pain Control
There may be discomfort in the surgical area. Oral analgesics, muscle relaxants, and non-steroidal anti-inflammatory medications may be used as prescribed by your physician. Dr Yeung has found that the routine post operative use of long acting opiods, augmented by short acting medication, and the use of interferential neural stimulation (RS Medical) will help with your post-operative recovery. You may feel transient some numbness and weakness in your leg from the local anesthetic used during surgery. This will usually start improving the first post op day. Occasionally, when the feeling comes back you will feel pain in the same or different area when the anesthetic wears off. Report this to Dr Yeung, and he will monitor it. Depending on your surgical findings, there may be some expected nerve discomfort, especially if the herniated disc had to be freed from the irritated nerve, or if an inflammatory membrane was ablated. You may experience post-op muscle spasm. This can be treated with medication or spinal blocks. Dysesthesia, if it occurs will usually go away in one week to several months. Rarely, it may be longer. How aggressively it is treated depends on its severity. If severe, it is usually treated aggressively with foraminal epidural blocks, sympathetic blocks, and medication. It is imperative that you contact Dr Yeung if this occurs so it can be treated and resolved optimally.Hospital Stay: Not needed
You will remain in the recovery room until you are alert enough to leave. Have someone available to drive you home. Under certain rare circumstances, you may be advised to stay overnight in the hospital. If this is the case, the surgical facility will arrange your transfer. You should be able to rest comfortably at home or in your hotel. If you are from out of town, it is usually safe to travel one or two days after surgery, but an overnight stay is recommended.Diet
Follow your regular diet. You may eat after leaving the surgical facility.Elimination
Avoid straining to have a bowel movement; a laxative may be used if needed, especially if you are taking opiod analgesics.Hygiene
You may shower 1-3 days after your surgery. No tub baths or hot tubs for about one week or until the wound is dry and healed.Activities of Daily Living
Light activities may be resumed the evening of surgery. Assistance may be needed the first few days with food preparation, lifting, and cleaning.First postoperative week
Moderate activities with rest periods as needed. No sexual relations until you are well on your way to recovery. No lifting, bending or twisting. No lifting of more than 5 to 15 pounds after 1 week; no lifting over 25 pounds for 6 weeks. You may return to work within 1 to 4 weeks after surgery or as able. You may resume driving 1 - 2 weeks after surgery or sooner if you are able to do so safely-remember to maintain neutral positioning-do not slouch.Body Mechanics
Important to maintain a neutral spine position with all postures and positions. Bend at the hips, knees, and ankles while keeping your back in neutral. Do not twist or forward bend at the waist. Coughing or excessive strain on your back in the first 3 months may result in recurrence of your leg pain from a recurrent herniation. Standing - weight evenly distributed on feet, keep knees soft, tighten buttock muscles. Standing to sitting - bend at hips and use a step position. Sitting - feet flat on the floor, weight through your sitting bones and back straight. Avoid sitting for more than 40 minutes at a time without a break. Sitting to side lying - no twisting, lower to side and brace with abdominals. Side lying to back lying - brace with abdominals and log roll.Exercises
Strenuous exercise such as tennis or skiing may be resumed when indicated by your physician. WalkingWeek 1: 10 minutes - 3 times/day
Week 2: 15 minutes - 3 times/day
Week 3: 20 minutes - 3 times/day
These are walking guidelines only - you may walk as much as tolerated as long as your pain is not increased by walking.
Abdominal Bracing Gluteal Sets Partial Sit-Ups Hamstring Stretch Quadriceps Sets Side lying Quad Stretch Sit to Stand Transfers Calf Stretch Press-Ups Swimming may be resumed 7 to 10 days after your procedure. 2-4 weeks after surgery, a formal program emphasizing lumbar stabilization followed by McKenzie type extension exercises is recommended for maximum benefit. If your surgery involves multiple levels or if it is primarily for discogenic pain, it is recommended that physical activity be restricted for 4-6 weeks to allow the annulus to heal and strengthen.Wound Care
There will be tape strips across the incision which will fall off after several days. There will be a small dressing that may be removed the 3 days after your procedure. Sutures are not necessary. Have someone check your wound site for increase in redness, drainage or swelling. Monitor your temperature - if your temperature rises above 100 degrees or any of the above wound changes occur, contact Dr. Yeung's office. A follow-up appointment will be scheduled for you at one or two weeks postoperative with your surgeon.In general, your choice of an endoscopic approach to your back problem is similar to choosing an arthroscopic approach to the knee or shoulder compared to the open approach. The results are similar, but the surgical morbidity is much less. You are encouraged to discuss all alternative approaches for your condition with your physician. It is hoped that this information will allow you and your physician to make the choice that is best for you.
New Developments
Recent advances in endoscopic surgical technique has allowed for successful endoscopic treatment of conditions such as Failed Back Surgery Syndrome caused by recurrent disc herniation, lateral recess stenosis, foraminal osteophytes, facet cysts, and many degenerative conditions of the lumbar spine such as degenerative and isthmic spondylolisthesis. Where the patho-anatomy can be accessed through the foraminal approach, treatment options may be possible. Biologics are also being considered for tissue healing and regeneration.
This approach is also possible for nucleus replacement or fusion. Advancements are being made yearly, and more alternatives to fusion will be available for painful degenerative conditions of the lumbar spine each year.
Glossary
Nucleus: The inner portion of the disc which has a gel-like consistency composed mostly of water and is surrounded by the annulus fibrosus (collagen).
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