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LUMBAR AND/OR SACRAL NERVE ROOT INJURY DUE TO HERNIATED DISC PART 1: PATHOLOGY AND CONSERVATIVE TREATMENT (A Patient Information Service) "Herniated Lumbar Disc" is usually a painful condition for which patients request assistance. It is essential to recognize that most patients can and do recover very satisfactorily from this experience without resorting to surgical intervention. The term commonly used for this non-surgical therapy is "CONSERVATIVE TREATMENT." It is an "active" form of treatment, which requires consummate self-discipline and patience since the tissues involved in this disease process heal very, very slowly.Hopefully when you have a better understanding of the underlying disease process and the pathological anatomy you will recognize the course of therapy that is best suited for you. There are some anatomical diagrams in the back of this booklet that should assist you in comprehending the text that follows. Disc material is "rubbery" in consistency. The disc acts as a "shock absorber" between each Vertebral Body and lies in front of the Spinal Canal. The disc is part of a multiple joint system at each level of the Spinal Column. The degree of motion at each spinal level is determined by a number of factors including the size, shape and angle of the interdigitating joints (Facet Joints) between each vertebra as well as the strength of the ligaments and muscles that join one vertebra to the next. The disc itself is also part of this system that changes over time as we age. Each disc has several components. The center region (Nucleus Pulposus) is more viscous. A multilayered and very dense capsule (Annulus Fibrosus) confines it. This entire structure is held in its position between two vertebrae by tenacious ligaments which themselves are attached to the bony vertebrae. The ligaments virtually encircle the disc. They are particularly dense in two areas running vertically in front (anterior) and in back (posterior) of the disc area. These are called the Anterior and Posterior Longitudinal Ligaments. They play an important role in the pathological process of "herniated discs", as well as in the long-term recovery from either conservative or surgical treatments. Despite apparently successful treatment (surgical or non-surgical) there is an element of risk for a recurrence of the condition. The ligament (most particularly the posterior longitudinal ligament) plays a vital role in this process. The process of "aging" (when used in relationship to the disc and the various joints of the spinal column) begins fairly early. The rate at which it progresses depends on a number of factors, some of which can be influenced by "life style" and habits. Others are less amenable to an individual's control. Genetics or inherited factors (with the exception of certain very rare diseases) probably do not play any significant factor for the average patient. Humans, by virtue of their bipedal (walking on two lower extremities) nature, subject their spines to forces on a daily, relentless basis that combine to accelerate a natural aging process. It is important to recognize that this affects all of the joints of the spine as well as the discs. The lower two lumbar levels (fourth and fifth lumbar, L4-5; fifth lumbar and first sacral, L-5, S-1) assume a disproportionate weight-bearing burden by virtue of their location in the mechanism and function of the spine. This "daily" trauma is, to a large extent, unavoidable. Other uncontrollable factors that further accelerate this process include congenital abnormalities of the spine (defects in the bone and/or muscular parts of the spine that we are born with) or developmental defects of these structures (those diseases which develop after birth — such as progressive abnormal curvatures called "Scoliosis"). For each person there are many more factors affecting the "aging" or progressive "degenerative" process, that we can control, which are influenced by daily activities and life styles. Obesity and "over-weight" conditions add an unnecessary weight-bearing requirement. Heavy lifting and repetitive bending (particularly when standing up and leaning over at the waist to lift something) are two factors that are frequent contributors in all societies that require or encourage heavy work. Athletes or individuals who pursue certain sports activities add another dimension of accelerated disc and joint deterioration because of the added repetitive trauma to these structures. Whether it is in a weight lifter or jogger, football player or tennis enthusiast, each pursuit exacts some price with respect to the spine and discs. None of this should be misconstrued by the reader as suggesting that these activities are either dangerous or undesirable. Good physical conditioning helps to assure general wellness and is very desirable from the point of view of slowing the progressive degenerative processes that the spine is inevitably subject to. It is merely a question of degree. We all must recognize that we pay a price for some of the things that we do. The spine and its components are among those parts of the body where added "wear-and-tear" frequently results in an accelerated degenerative condition that ultimately may cause that part to fail to continue to function adequately. 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. Recent research has resulted in several devices for "lumbar disc replacement", several of which have been approved by the FDA for human implantation. This is a highly controversial area which is discussed in more detail in Part 2 of this Patient Information Series. The related spinal joints (called Lumbar Facet Joints) are points of motion which, in time, produces excessive "wear-and-tear". When spinal joints are involved in this "wear-and-tear" process, they react in a characteristic method to "protect" themselves. The joint fluid ("Synovial Fluid") and joint surface lining (called "Synovium") react in a characteristic fashion where the lubricating fluid disappears and the lining becomes thicker, more abundant ("Hypertrophic") and far less efficient. The Facet Joints concurrently react to produce more bone in an attempt to halt the wearing away. This new bone results in a progressively larger ("Hypertrophic") joint which encroaches on the spinal canal (where spinal nerves exist) making the canal narrower ("Spinal Stenosis"). This process involving the various components of these joints is called "Degenerative Arthritis" or "Osteoarthritis". Another characteristic aspect of this "new bone" formation is the formation of "Bone Spurs" (also called "Osteophytes.") The process of degenerative arthritis is usually a very slow one. It is, to a degree, inevitable in everyone. Some people, for many of the reasons outlined previously, encounter it earlier and to a greater degree than others do. Despite a well-advanced case, some people are not significantly affected either by pain or neurological injury, whereas others can be incapacitated. Unfortunately, there are no medications or treatments that can reverse this "degenerative" process. Anti-inflammatory drugs are usually helpful in reducing an acute flare-up of joint inflammation. Occasionally this process of progressive abnormal bone formation results in very substantial Spinal Canal Stenosis (narrowing). This narrowing is consequent to the overgrowth of the Facet Joints as well as the Ligamentum Flavum ("Yellow Ligament"). This special ligament lies beneath each Lamina connecting one lamina to each other as part of the normal stabilizing mechanism of the spine. The Ligamentum Flavum is subject to stresses just as the Facet Joints are and, as a result, it participates in this counter-productive degenerative process which ultimately culminates in a pathologically thickened (hypertrophic) and partially calcified Ligament. Once the Ligamentum Flavum and Lumbar Facet joints have become sufficiently overgrown to seriously compromise the diameter of the spinal canal and Neural Foramina, substantial pressure is exerted upon the Spinal Nerve Roots. This may result in severe pain in the buttock and leg(s) when trying to walk some distance, a condition known as "Cauda Equina Claudication." When the pain becomes a major factor impairing the quality of life, then treatment becomes necessary. In our neurosurgical practice, we frequently see patients who have severe Spinal and Foramenal Stenosis. It is this narrowing that squeezes the nerve roots in the spinal canal and results in severe pain when trying to walk. There is another (and probably more common) cause of "claudication" which results from marked impairment of the blood supply to the lower extremities, another manifestation of "Atherosclerosis" ("Hardening of the Arteries") The differentiation between these two conditions is usually apparent using simple methods during a physical and neurological examination. Occasionally a more detailed investigation is required. Patients suffering from claudication, may have some degree of isolated muscle weakness and/or sensory loss. Once the claudication is severe, surgical treatment becomes an important consideration. A "Herniated Disc" (also called slipped, ruptured, misplaced, displaced, dislocated) is a pathological situation. Although most patients recover quite well without surgery, it is a sufficiently common problem that frequently recurs multiple times in those affected by it. One of the most frequent causes of the "herniated disc" is a lifting or bending injury. Too much pressure is exerted on the central portion (nucleus pulposus) of the disc. This results in pressure against the confining capsule (Annulus Fibrosus) and Posterior Longitudinal Ligament which are then stretched and injured. The dislocated portion of the disc may push into the bony spinal canal to press the nerve roots against the bone of the spinal canal resulting in injury to the nerve root. A damaged nerve root responds in a characteristic response, called "edema" ("swelling".) Unfortunately it swells against a hard bone surface — the spinal canal producing additional pressure on the nerve root and its blood supply, which results in more injury to the nerve root and progressively more swelling. Bed Rest In order to recover from this problem, two events must occur. The pressure must come off the nerve root and the swelling must reverse. These events can be promoted in a number of ways. The easiest method of management is the most effective in accommodating both of these requirements. It is straightforward and readily available to all. It is BED REST.BED REST accomplishes two things. By lying down, the pressure on the disc, that ordinarily occurs when humans are upright, is diminished. The inherent elastic strength of the Annulus Fibrosus and Posterior Longitudinal Ligament will assist in the forcing the Herniated Nucleus Pulposus to recede into the disc space, thus, reversing the pressure on the nerve root(s) which then allows the nerve root swelling to subside. The pain that accompanies this problem also will improve significantly, particularly the portion that is deep in the buttock and/or leg and foot. Back pain is a frequent symptom that brings the patient to the physician and may be a symptom of some other medical conditions completely unrelated to actual spine problems. Your physician will review the history of the problem and conduct a physical examination that will include an evaluation of the spinal column and nerve roots. The experience of a painful, stiff back is familiar to most of us. The "stiffness" is usually the result of spasm or tightness of the powerful muscles ("Paraspinal/Paravertebral Muscles") that lie along both sides of the back of the Spinal Column. The spasm is the body's way to attempt to immobilize the damaged joints. When the muscles contract (tighten), they reduce the amount of movement that the joints would ordinarily have. However, muscle spasm itself may be quite painful. Some patients describe the tightness of the muscle as "knots." Local application of heat (heating pad, moist or dry "packs") or ice frequently offers significant relief for the muscle spasm in conjunction with lying down. Careful attention not to injure skin with the ice or heat is important. Massage (with or without liniment, balms, salves or oils) also may offer welcome relief from the pain of muscle spasm. In many cases of "back pain," the problem is only with the muscle (such as a muscle strain), and these measures often provide satisfactory relief. However, any persistent or recurring, severe back, hip or leg pain deserves a thorough evaluation by your physician. Medications are frequently used to help relieve some of the pain of these problems. Mild pain relievers are often necessary. Muscle relaxing and anti-inflammatory medications are also commonly utilized. However, some caution is needed. It should be remembered that pain is one way that the body has to alert you that something is wrong. If you take medication to relieve pain and continue to pursue the activities that are producing damage, then you are probably doing a serious disservice to yourself. The Role of Steroids "Steroids" are very powerful "anti-inflammatory" medications. Steroids are routinely used to limit and/or reverse the "edema" (swelling) that occurs when the Brain, Spinal Cord or Nerve Roots are damaged.An increasingly popular treatment method is the injection of steroids (with or without an anesthetic agent) into the spinal canal in an attempt to reduce the swelling of damaged nerve roots. This procedure, called "Epidural Steroid Injection" or "ESI" involves introducing a needle or catheter inside an already compromised spinal canal to deliver the steroids that are injected "suspended" in a liquid rather than dissolved in "solution". There are several issues surrounding this controversial "treatment". The placement of the ESI catheter could result in more damage to the nerve roots, adverse reactions to the injected medications and hemorrhage from the many small blood vessels in the spinal canal. When the "fluid" portion of the injected material is absorbed, the "Epidural Steroid suspension" or ("carrier") substance remains behind as a "sludge" that causes further scarring within the spinal canal. We have had very many occasions to operate on patients who have had Epidural Steroid Injections and have routinely found the residual "sludge" material in the Epidural Space stuck to the Dura Mater and/or calcified within the Ligamentum Flavum. Steroids cannot improve upon an "extruded" or "herniated" disc; does interfere with the normal healing process of the damaged Posterior longitudinal Ligament; cannot positively affect any element that is causing Spinal and/or Foramenal Stenosis such as Degenerative Arthritic Lumbar Facets, Synovial Cysts and/or Ligamentum Flavum overgrowth. Nevertheless, steroids can help to relieve the pain, tingling/numbness and weakness that may result from nerve root swelling occurring in conjunction with an acutely injured nerve root in cases of a Herniated Disc or Spinal (and/or Foramenal) Stenosis. In our experience, it is more appropriate to attempt a short course of oral steroids (taken in pill form by mouth in those patients where it may be of benefit) rather than risk injections into the spinal canal. Oral steroids (usually in the form of "methylprednisolone") are usually sufficient to achieve the desired result. In some patients, more potent steroids ("dexamethasone") may be required. Lumbar "Traction" The old treatment concept of "Lumbar Traction" is being re-established using more modern technology including "computerized devices". All of the "traction" methods attempt to decrease the pressure inside the disc space by using some type of pelvic "pulling" force in an attempt to "separate" the disc spaces (a matter of a few millimeters). This creates a "vacuum" allowing the "herniated" disc fragment(s) to recede into the disc space. Simple devices include a corset attached to a rope, pulley and weight system that the patient can use, in bed, at home. Another is a "gymnastic" set-up where the patient "hangs" in an inverted position and uses his own body weight as the "traction" force. Other more sophisticated computerized traction devices can be found in some chiropractic, orthopedic and neurosurgical offices. Clearly there is some merit to these treatments although it is important to carefully select those patients for whom this would be appropriate.Factors Limiting Recovery The limiting factors for recovery, and also those which may result in incomplete recovery or recurrence of the herniated disc, are the tissues that are intimately related to the disc that were damaged as well. Those tissues are the disc capsule (Annulus Fibrosus) and the confining Posterior Longitudinal Ligaments. Once these are stretched ahead of the herniated disc, they are very slow to recover. Even when the disc recovers its more normal position and the capsule and ligaments are no longer under the forces of stretch, they are still in a weakened condition. Some patients are fortunate in that the ligament heals well after the first episode and never bothers them again. In others, these structures never regain adequate strength resulting in multiple recurring episodes over varying periods of time from months to years. Alternatively the initial episode may be sufficiently traumatic that conservative therapy, no matter how carefully it is carried out, may fail and other more aggressive treatment techniques may become necessary. No one can accurately predict, ahead of time, what course is determined for a particular patient with a herniated disc (except in a very special set of circumstances which invariably are accompanied by serious or advancing neurological deficit). Only after an initial trial of conservative therapy can one begin to identify what further treatment course should be recommended. As a general rule, strict and complete bed rest on a well-designed mattress (not too hard and not too soft) for a minimum of five (5) days is indicated in most patients. The majority will improve. In these cases complete bed rest for an additional nine (9) to fourteen (14) days will be required to allow the capsule and ligaments to begin to heal. In cases of a large disc herniation, the capsule and ligament will not heal for months (if ever). During this time the patient should exercise care, caution and good common sense with respect to their activities. The problem is with the Annulus Fibrosus capsule and Posterior Longitudinal Ligament. Early return to an exercise regimen that produces pressure on the disc may very well result in an early recurrence. Common sense alone should indicate which activities and body positions are likely to be injurious. Activities that produce pain should be avoided. Pain is the body's way to alert us that something is wrong — tissues may be injured. Exercise programs obviously have no place in the early management of this problem.There are some patients who, despite a trial of complete bed rest, do not improve or suffer a recurrence early after getting up from bed rest. In these situations, both the ligament and disc capsule are so badly damaged that they cannot hold the disc in place. This is called an "Extruded Disc" and refers to a situation where the disc material has torn a hole in the confining disc capsule and ligament allowing part of the disc to escape into the spinal canal. The capsule and ligament are made of elastic tissue resulting in the closing over of the hole through which the disc "extrudes". The disc cannot be repositioned by any method, and these patients become surgical candidates. Spinal manipulation is inappropriate and potentially very likely to produce further neurological damage in the case of an extruded disc. No reasonable force could push this disc back into place. Back pain is often the major symptom of muscle strain, spinal joint problems or a herniated disc. Hip and leg pains are usually the result of pressure injury to the nerve root. The experience of tingling, numbness and/or weakness of leg (or foot) muscle are the result of more serious damage to the nerve roots. The medical term for a nerve root injury is Radiculopathy. The presence of symptoms of radiculopathy requires early medical evaluation and treatment. For most patients, proper treatment under medical supervision will alleviate the problem early and reduce the likelihood for and the extent of a chronic, more severe disorder. Additional Investigation Your physician, after an initial examination, may order plain x-rays of the lumbar spine. These x-rays allow for the evaluation of the bone structure but cannot identify whether or not a herniated disc is present. There are some other examinations which can be obtained; however, they are much more expensive and unnecessary for every patient.Computerized Tomography (CT or CAT) scan is an x-ray examination that permits us to evaluate both the bone of the spinal column and (to some extent) the disc structures. Its primary usefulness, for spine patients, is in evaluating bone anatomy. Magnetic Resonance Imaging (MRI) scan is a non-x-ray technique that is often used as the first (or screening) neuroimaging method in many patients. While it has some limited usefulness in evaluating bone anatomy, it is an excellent technique for evaluating the Spinal Cord (which is rarely involved by lumbar region disc disease since the spinal cord "ends" near the L1 level), Nerve Roots and also allows us to look at the anatomy of the disc. Oftentimes this is the only neuroimaging method that we will need. In rare instances it will demonstrate the presence of a tumor (almost always benign) in the spinal canal. MRI scanning is very useful in evaluating the Thoraco-lumbar junction of the spine. The Thoracic area of the spine lies just above the Lumbar region. The "junction" between these two regions is a frequent location for advanced degenerative disease in older people. There is one other investigative technique that is very important. "Myelography" coupled with "Post-myelographic CT Scanning" is regarded as the "gold standard" neuroimaging method for evaluating spine problems. However, we reserve this for patients who are operative candidates in whom MRI and/or CT scans have not fully explained the anatomical condition. This is an "invasive procedure" requiring the placement of a needle and a radiographic dye substance into the spinal canal and is not to be considered as part of a routine evaluation for spine patients nor is it required for all patients who are to undergo spinal operative intervention. The specific indications for this procedure are reviewed in PART 2 of this Patient Information Series. Other investigation methods such as Bone Scanning, Bone Density testing and Positron Emission Tomography (PET) are generally not required for patients with new onset of symptoms. In the event that routine testing (such as reviewed in the preceding paragraphs of this document) does demonstrate some additional problems then these other tests may become appropriate. The details of the follow-up care and treatment regimen for the recovering patient, after an initial favorable response to conservative therapy, are usually custom designed for that patient. When to begin to use exercise and which types of exercise are matters to be reviewed with the physician, as is the concern for a properly nutritional diet. Diets based on food fads can be harmful by virtue of not providing agents necessary for the recovery of damaged tissues. A nutritionally well-balanced diet, with an emphasis on "proteins" (the "building blocks" of tissue repair, is necessary. Where obesity is an additional factor, a major effort at weight reduction must be made, taking into account that "proper" nutrition must be provided to the damaged tissues. In these cases a firm recommendation is usually made to consult a nutritionist and/or a physician who is well acquainted with weight control and weight reduction techniques. A final thought concerning this problem of a herniated disc should be kept in mind. There are no "quick fixes" available. A basic understanding of the underlying injury to tissues will help guide the informed patient to seek their choice of treatment. Whatever choice is made, one should remember that damaged tissues take time to heal and, when in a weakened condition, are more likely to be re-injured more severely. Despite all of this, most patients recover satisfactorily. It is only a small minority of patients with "back pain" who ever really require surgical intervention.
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All content ©2024 by Neurosurgical Consultants, P.A. Author, Martin L. Lazar, MD, FACS All Rights Reserved. See Usage Notices. |