B. CT Scan does not permit evaluation of the Disc Space other than to assess the intervertebral distance ("Disc Space collapse"). However, it provides better information about the Vertebral Bone and particularly of the Lumbar Facets.
DEGENERATIVE DISCS DO NOT, IN AND OF THEMSELVES, REQUIRE TREATMENT. WHILE THERE ARE METHODS TO DEMONSTRATE THAT THE DISC HAS BEEN "DAMAGED", THAT FACT ALONE DOES NOT JUSTIFY, IN OUR OPINION, ANY FORM OF SURGICAL MANIPULATION OR INTERVENTION.
A. Spinal Fusion
There are a number of ways to "Fuse" (permanently immobilize) one or more Disc Spaces.
B. "Artificial Disc"
That the Disc itself is subject to progressive degenerative changes, with or without the influence of the "accelerating" factors, is undeniable. Some joints in extremities can be successfully replaced (knees, hips, and finger) although there is a limit as to how long replacement joint materials will last.
"Artificial Disc Replacement" is being recommended by some of our more aggressive colleagues, as a primary surgical option for patients with Degenerative Disc "Disease" and/or Herniated Disc. THIS IS A HIGHLY CONTROVERSIAL AREA with proponents using SEVERAL DIFFERENT TYPES OF THESE ENTITIES WHICH ONLY RELATIVELY RECENTLY HAVE BEEN APPROVED BY THE FDA AS MECHANICAL DEVICES SUITABLE FOR HUMAN IMPLANTATION. THE CONCEPTS FOR THE UTILIZATION OF THESE DEVICES ARE STILL BEING EVALUATED.
Unfortunately this is one operation THAT CANNOT BE REVISED WITHOUT SIGNIFICANT RISK TO LIFE AND NEUROLOGICAL FUNCTION should complications ensue from the primary procedure. Currently there is no long term patient data on how long the synthetic materials or the various designs will hold up to the daily forces exerted on them with various postures. "Bench testing" in the form of machines made to duplicate human motion suggests that there is a reasonable longevity to these products. However, it is clear that in cases of replacement of other joints, such as knees or hips, there are real limitations to how long these artificial joints will last (frequently no more than 10 years.)
Surgical intervention in patients who suffer Neurological Symptoms from a herniated lumbar disc and/or surgically significant degenerative arthritis of adjacent joints become indicated in those patients where a serious trial of conservative treatment has failed; where neurological deficits are initially so severe that further delay will probably result in major permanent neurological deficit; where the neurological deficit is advancing (worsening) despite the conservative treatment or where nerve root compression, from narrowing (stenosis) of the spinal canal or nerve root exit area (neural foramen) is causing severe symptoms of Cauda Equina Claudication (see Lumbar Spine Information – Part 1.)
The presence of the symptom of Back Pain (by itself and not accompanied by any mechanical physical signs of nerve root compression, neurological involvement of the particular nerve root[s] or structural spinal instability) is rarely a valid indication for surgery. Recognizing that no reasonable person would wish to undergo an unnecessary operation, it is, therefore, important for patients with back pain to understand this concept if those who are not going to benefit from surgery are to avoid it.
The following information reflects our philosophy and collective experience, relating to the treatment of thousands of patients with these problems over the many years of our active involvement in Neurological Surgery.
Major advances in the field of NEUROIMAGING have improved the ability of neuro-radiologists and neuroimaging techniques to provide us with much more accurate information about the actual pathological situation affecting the spinal column, spinal canal and nerve root(s). CT (Computed Tomography) scan (also called CAT Scan-Computerized Axial Tomography) is one of these techniques. It should be recognized that this x-ray examination is subject to technical limitations and that not all CT scan machines or the people who run them or the radiologists who attempt to interpret the studies are as accurate as we would want them to be. In the event that a CT scan is supervised by a Neuroradiologist and interpreted by him (or her), then the chance for error has been reduced. The CT scan is "NON-INVASIVE" (no needles are used to penetrate the spinal canal). The effects of the expected aging process frequently produce changes that become evident on CT scan. A "degenerative disc," "disc space narrowing," "degenerative arthritis with bone spur formation," "narrowing of the spinal canal" (the medical term is "stenosis") and "bulging" (of one or more discs) are among the diagnostic impressions frequently reported by radiologists who review and interpret these studies. The patient must be prepared to realize that many, if not all, of these "conditions" are the result of the progressive changes of the aging process and may very well NOT respond to any form of surgery and SHOULD NOT be operated upon in the absence of an accompanying clear-cut neurological indication. (There are rare exceptions to this.) What the foregoing should mean to the informed patient is the following: "The mere presence, on the CT scan, of a bulging disc (or discs) coupled with other 'pathological' situations does not mean (in and of itself) that surgery should be done now or later."
MRI (Magnetic Resonance Imaging) has evolved as the single best Neuroimaging technique for the initial evaluation of the lumbar spine. It can be excellent for evaluating the spinal cord and some disc anatomy but does not give as detailed information about bone anatomy compared to CT. Often times when this information is placed in the context of a reliable neurological examination, the MRI derived information is sufficient for us to make an accurate assessment and to make a definitive surgical recommendation. In other words, the newer MRI technology has advanced to a point that it is frequently the sole source of "Neuroimaging" required for many patients. MRI scanning can also be of considerable help when evaluating certain post-operative conditions.
There appears to be a trend toward elucidating new "diseases" of the spine as more sophisticated and refined imaging methods become available, the result of which is that some of our very aggressive surgical colleagues have identified newer indications for surgical intervention. One of these "new diseases", for example, is called the "black disc". This appearance, seen on MRI (Magnetic Resonance Imaging) scans, is a normal phenomenon of diminished water content (dehydration) of the disc related to the natural process of aging and use. Depending on the extent of one's life-long physical activity (at work and/or with sports activities) and as we get older, our discs are subjected to more or less "wear and tear". This process results in some internal changes. The disc, which has a "rubbery" consistency under age 20, becomes less viscous, more dehydrated and more like "crab meat" as we age. The image of these changes appears on the MRI scan as "black". We wish to caution patients against assuming that something horrible is happening to their bodies or that this necessarily requires surgical treatment. We want to point out that this is, in most people, an entirely "natural" process of living and rarely is indicative of a "disease" process. In our opinion this is not a problem that should require surgical intervention in the absence of other more significant problems such as instability of the spine or neurological signs and symptoms.
For a number of reasons neither the CT nor the MRI scans may reveal enough of the structural situation of the spine for the surgeon to make a decision about the precise pathological anatomy upon which treatment alternatives and recommendations would be made. In this case the surgeon may request that a "MYELOGRAM" be done. This x-ray examination, conducted by a Neuroradiologist, involves the placement of a needle into the spinal canal. (The skin and underlying tissues are anesthetized with locally injected anesthetic agents.) A special dye substance is injected through the needle into a particular place in the spinal canal (subarachnoid space) where it mixes with the Cerebrospinal Fluid (CSF), and the pattern of the flow of the dye is watched on a special x-ray screen (called "fluoroscopy") similar to a television. In the event that a "mass lesion" is present in the spinal canal, Myelography can frequently outline its anatomical configuration. "Mass lesions" are any abnormal conditions in the spinal canal, which take up space and therefore, displace the nerve roots from their usual position. Herniated Disc, Bone Spurs, Synovial Cysts or Spinal Tumors (which are rare and most frequently completely benign) are examples of "mass lesions." Once again, this test is subject to some technical limitations, and the quality and accuracy of the study depends on these and the technicians as well as the radiologists performing and interpreting the study. Once the dye injection has been successfully accomplished and appropriate routine x-rays have been taken, the patient will be placed in the CT scanner. This phase of the study (known as "post-myelographic CT scan") is the most helpful imaging concept currently available. IT GIVES THE MOST PRECISE ANATOMICAL DETAIL OF THE BONE ANATOMY AND THE EFFECT OF STRUCTURAL PATHOLOGICAL CONDITIONS ON THE SPINAL CORD/NERVE ROOTS.
In the majority of patients who suffer from a herniated lumbar disc, Myelography is not required. Usually the CT or MRI scan gives sufficient information. Myelography is invasive; and although the risks of adverse reactions to the patient are very low, there are definite risks. An unnecessary myelogram is not in the patient's best interest.
There are some other forms of examination that are occasionally utilized. "Discography" and "Disco-CT Scan" (injecting a dye into the disc) is a painful procedure that has very limited indications and even more limited usefulness in helping to make clinical decisions. We strongly disapprove of this test and do not use it.
Diagnostic Nerve Blocks (injecting anesthetic agents near a nerve root or a facet joint) is being done with increasing frequency by some doctors. Unfortunately these procedures offer little to nothing diagnostically or therapeutically for patients with nerve root problems that are the result of herniated discs and/or spinal canal narrowing.
Electromyography (EMG) is an electrical test that is sufficiently reliable only in the hands of very capable Neurologists or Physical Medicine & Rehabilitation specialists. Tiny needles, inserted through the skin, measure very small electrical currents from nerves and the affected muscles. The test can provide some useful neurophysiologic information if properly done. The problem with the test is the wide variation of reproducible findings, which may render poor results making the examination unreliable. The degree of training and the extreme care, which the doctor brings to the test and utilizes in interpreting the results, are critical. This test is not necessary for most patients who are candidates for surgery. For others it may provide important information concerning fairly subtle neurological involvement.
Before undergoing any treatment, particularly an operation, it is reasonable to try to understand what will happen to patients if no treatment is undertaken.
Equally important is what will happen to patients who FAILED conservative treatment (patients suffering Lumbar Radiculopathy [injury to nerve roots] as a result of herniated or extruded discs with or without a component of spinal or foramenal stenosis or spinal stenosis and/or foramenal stenosis without the herniated disc) and a definitive operation is not done.
Several statements can be made about the "projected natural history." These are:
First, most Herniated Disc patients improve with a vigorous attempt at conservative therapy (initially with strict and complete bed rest) since the injury that resulted in a herniated disc is usually one where the Posterior Longitudinal Ligament and most of the Annulus Fibrosus remain intact (both are structures critical to holding a disc in place.)
Second, the degree to which patients subsequently remain free of symptoms depends on the extent of their initial injury (particularly to the capsule and ligament confining the disc) and the time that they allow, in the months following injury, for these structures to heal adequately.
Third, in the event that a nerve root is injured, the patient experiences pain and varying degrees of neurological deficit (such as tingling, numbness and muscle weakness).
Fourth, those patients who decide against surgery will continue to experience the pain for a fairly long time; however, the pain will eventually disappear once the nerve root dies. This could take weeks but more likely months to years.
Fifth, when the nerve dies the patient will be numb in the leg/and or foot region supplied by that nerve root. The muscles that receive their signals from the nerve will no longer work resulting in permanent paralysis. The degree to which this happens is variable in humans partly because of other nerve roots partially supplying similar regions and muscles. Nevertheless, it is unreasonable to expect, in these cases, to regrow a nerve supply to a paralyzed muscle.
Sixth, it is exceptionally rare for an "Extruded Disc" (one that has torn completely through the Annulus Fibrosus and the Posterior Longitudinal Ligament) to ever recede into its former "normal" position.
Seventh, when an extruded disc is not removed, more disc material could herniate through the already compromised Annulus Fibrosus and Posterior Longitudinal Ligament, placing more nerve roots at risk for serious injury.
The surgical procedures available for patients with herniated lumbar intervertebral discs and spinal and/or foramenal stenosis (narrowing of these spinal bone passages due to problems that are congenital and/or secondary to degenerative arthritis) have been utilized for many years. They are among the oldest operations ever performed on the nervous system. Modern trends have introduced some major advances. These are particularly related to the use of micro-neurosurgical techniques and specially designed instruments. In recent years we have introduced the more advanced techniques of Minimally Invasive Microendoscopic Surgery to spine surgery.
As a general rule patients who undergo these operations require a general anesthetic. Fortunately, modern anesthetic techniques have reduced the associated risk to life to a tiny fraction. The anesthesiologist will discuss the matters relating to the anesthetic and will be pleased to answer any questions that you may have.
There are certain basic surgical concepts to be understood before recognizing which particular procedure is chosen for a patient. Although degenerative changes affect more than one disc, it is unusual for more than one disc to require surgical attention at any particular time. Extruded discs (discs that have either broken through the confining capsule and ligament or have so damaged the ligament and disc capsule that they are no longer capable of holding disc material in place) are only rarely found to have come from more than one level. Removal of degenerative discs that have not frankly herniated as a "prevention measure" is not appropriate except in very isolated cases. The primary purpose of these operations is to relieve the pressure on the nerve root(s).
In the case of an extruded disc, the primary surgical purpose is to remove the fragment of disc that has escaped its confining capsule and ligament and relieve pressure upon the nerve root(s) and/or spinal cord. A secondary but equally important aim of surgery is to try to reduce the risks of recurrence of the problem. In most patients with an extruded disc, an attempt is made to remove as much remaining disc as possible from the disc space itself. This is in addition to removing the extruded fragment(s). In order for a herniation to have occurred, the confining capsule and ligament must have been severely damaged. Frequently there is a fairly large hole in these structures. Other fragments of disc could subsequently herniate from this disc space since the structures that help to prevent this (the capsule and ligament) have been damaged irreparably. Although it is not possible to remove every last fragment of disc from within the disc space, no matter how vigorous an attempt is made, the remaining disc is usually tenaciously bound to the bone of the vertebral body. While many surgeons restrict their operation for lumbar disc herniation to the removal of the herniated fragment(s), the reader should understand our rationale for removing as much disc material as possible in order to prevent the significant risk of recurrent herniation.
In many patients compression of the nerve root results from a combination of pathological conditions of which the herniated disc is one. Where bony spinal canal and neural foramen narrowing are also factors, it is important to remove the overlying bone which, then, allows for complete "decompression" of the involved nerve root(s). This is an essential part of the definitive operative management of these clinical problems.
Once the majority of the Intervertebral Disc has been removed scar tissue will eventually fill in the space from which the disc is excised. It is never as effective as the original disc was. However the scar can be sufficiently effective in subsequent "spine mechanics" provided proper healing occurs. In a similar way, the tear in the Posterior Longitudinal Ligament (which cannot be repaired surgically) will ultimately heal through scar formation. For both structures - the disc space and the Posterior Longitudinal Ligament - it will take three (3) months for the scar formation to be "firm" and six (6) months for it to become "solid". Allowing time for proper healing and limiting some activities in the early postoperative period are important factors contributing to the long-term success of these procedures.
The most frequent operations performed for these diseases involve an avenue of approach from the back (posterior). All of these techniques involve the removal of part or the entire "roof" (the "Lamina") of the spinal canal in the affected area. Removal of the lamina from both sides is a "LAMINECTOMY." Removal of the lamina from only one side is a "HEMILAMINECTOMY."
The most common operation involves removing only a thumbnail-size piece of bone from the lamina in order to gain access to the spinal canal where the herniated disc fragment is lying against the nerve root. This procedure is called a "LAMINOTOMY" (or opening in the lamina). The bony canal through which the nerve root travels as it leaves the spinal canal is called the "neural foramen". It is almost always desirable, and frequently necessary, to remove part of the roof of this foramen in order to decompress (relieve pressure on) the nerve root. This is called a "FORAMINOTOMY."
In the event that a bone spur is the culprit causing the nerve root compression, it may be possible to remove it. This is usually the case if the spur originates from the Facet Joint lying directly behind the nerve root. However, if the bone spur comes from the front of the spinal canal, it may not be possible to safely remove all or any of the spur. The decompression of the spinal canal and the affected neural foramen is most frequently very successful in treating the symptoms and signs of this problem. While it is quite evident that not all the bone spur is removed and that it could continue to enlarge, it is actually unlikely to cause any further major difficulties provided an adequate decompression has been accomplished.
Most patients undergo these operations to relieve the pressure being exerted on the Nerve Roots. They already have some Neurological Deficit(s). The older the patient is at the time of operation, the longer they have had the Neurological Deficit and the more severe it is, the less likely they are to recover. Whatever Neurological Deficit persists one year after operation, is likely to be permanent.
MINIMALLY INVASIVE MICROENDOSCOPIC SPINE SURGERY
There are now two technical options available with which to perform the surgery. The Minimally Invasive Microendoscopic Surgery approach involves a very short incision just off the midline to the side of the main problem. Rather than stripping muscle from the bone of the spine, as is done in the case of the more traditional (and very effective) Microsurgical Operation, this newer technique separates the muscle fibres using a specially designed small tubular retractor (called a "Port"). These "Paravertebral muscles", which run vertically on the side of the Spinous Process and Lamina, would customarily be removed from and then held in a retracted position from the bone of the spine in the more traditional Microsurgical approach. In both surgical methods a bone window is fashioned in the Lamina. It is through this opening that we gain access into the spinal canal. The nerve roots are protected by a "leather-like" covering (the dura mater). Once this is identified, the interior of the spinal canal is inspected. Frequently, the nerve root is tightly stretched over the extruded disc fragment(s) and/or bone spur. It must be protected and gently mobilized and perhaps moved a short distance in order to allow access to the mass inside the spinal canal. The extruded disc is then removed. In the event that the hole in the ligament and disc capsule (created as a result of the disc breaking through these confining structures) is not large enough to permit easy placement of instruments used to retrieve the remaining disc material from the disc space, then the hole is enlarged. After the remaining disc has been removed, the tissues are allowed to regain their former positions.
In the Minimally Invasive Microendoscopic Surgery the large back muscles, the fibres of which were spread apart by the special tubular retractor, fall back together. (In the more traditional technique these muscles would be scraped and separated from the bone and then must be re-approximated with strong suture material.) The skin incision is then closed in both types of surgery. In our cases, this is accomplished with "hidden" sutures.
Most patients who undergo these operations awaken from surgery essentially free of the severe pain that they had previously endured. Patients generally report that the pain from the incision in the back is not nearly as bothersome as that which they experienced preoperatively. The majority of patients are mobilized out of bed when they are awake and alert. It takes approximately three to four hours to completely recover from the effects of the anesthetic. It is important to get out of bed early unless you have been instructed otherwise. You will be asked to avoid taking excessive narcotic analgesic (pain reliever) in the early postoperative period in order to allow you to be mobilized. Narcotics make people sleepy which would preclude our staff from allowing you to be out of bed. The discomfort from the incision is rarely seriously painful. Actually once you are out of bed and walking, the pain is usually lessened even further.
Patients, who undergo a "laminectomy" procedure, should recognize that this more extensive operation (compared to a "laminotomy" for a herniated disc) may result in more discomfort, more analgesic medication and a longer stay in hospital. These will be discussed on an individual basis with the patient involved.
BILATERAL LAMINENECTOMY/UNILATERAL APPROACH
Bilateral Decompressive Laminectomy with Bilateral Foramenotomies using a unilateral (one-sided) approach is now possible, in many patients, using Minimally Invasive Microendoscopic Surgery. This highly advanced and technically demanding operation constitutes a major technical advance in the treatment of many patients with spinal stenosis as a component of their clinical problem. Minimally Invasive Microendoscopic procedures allow us to effectively remove and "decompress" BOTH sides (bilateral) of the spine using a ONE-SIDED (unilateral) APPROACH. This is a significant change compared with the more traditional operation which requires the stripping of paravertebral muscle from bone on both sides of the spinal column. In this Minimally Invasive UNILATERAL operation the paravertebral muscles are less affected resulting in significantly diminished post-operative pain. This technique is not always possible in all cases. Where it might apply, your surgeon will discuss it with you. (This advanced procedure is also utilized for the Minimally Invasive Microendoscopic management of certain spinal cord tumors.)
In patients suffering "Cauda Equina Claudication" (pain in the legs while walking) due to "Spinal Stenosis" (narrowing of the spinal canal-usually resulting from severe degenerative arthritis with or without "Spondylolisthesis" [see pages 13 & 14]) the option of Minimally Invasive Microendoscopic techniques offers a considerable advantage compared with standard Microsurgical operations. Multi-level decompression procedures are usually accomplished using a multiple "port" technique. In our practice experience we have used up to three (3) ports in order to effectively "decompress" Lumbar Spinal Stenosis at up to four (4) levels.
Additionally, we have recognized that the majority of patients undergoing a two (2) or three (3) level Minimally Invasive Bilateral Laminectomy using a Unilateral Approach, are able to and are desirous of leaving the hospital on the same day as surgery. This means that the operations are done through our "Day Surgery" facility.
INTERSPINOUS PROCESS DECOMPRESSIVE SYSTEM
Interspinous Process Decompression System is a relatively new Minimally Invasive procedure that is used to relieve symptoms of lumbar spinal stenosis, a narrowing of the passages for the spinal cord and nerves. There are several implantable devices, either made from titanium and/or other materials, that are designed to be placed between the "Spinous processes" (the thin projections from the back of the spinal bones to which muscle and ligaments are attached) of the symptomatic levels of the lower (lumbar) spine in order to limit extension of the spine in the affected area. X STOP® is one such device that has achieved FDA approval (others include the "DIAM device"; the "Coflex"; the "Wallis", the "Spire" etc.) The primary goal for this therapy is to relieve some or all of the symptoms of lumbar spinal stenosis and may improve a patient's ability to function. However, this does result in a larger, wider spinal canal as would occur with a "Laminectomy".
The implant is indicated for treatment of patients aged 50 or older suffering from pain or cramping in the legs (neurogenic intermittent claudication) secondary to a confirmed diagnosis of lumbar spinal stenosis. The use of this device is indicated for those patients with moderately impaired physical function who experience relief in flexion from their symptoms of leg/buttock/groin pain, with or without back pain, and have undergone a regimen of at least 6 months of nonoperative treatment. The devices may be implanted at one or two lumbar levels.
This new technology also has the potential for use as "fixation" or "stabilizing" procedure when combined with other Minimally Invasive techniques such as in older patients with a mild form (Grade 1) spondylolisthesis and spinal stenosis. In this case a Minimally Invasive Decompressive Laminectomy may be combined with the insertion of the Interspinous Decompression System in order to assist in maintaining "stability" of the spine. This device should not be used in patients with: