David S. Klein, M.D.

Diagnostics and Spinal Pain

INTRODUCTION:

Low back pain is one of the most common problems that plague our society.  The principal difficulty with the treatment of pain in the back stems from the simple fact that most therapeutic interventions are based upon improper, incomplete or inadequate diagnosis.

Simply stated, if the diagnosis is not correct, the treatment is doomed to fail.

Most difficulties that present as back pain are muscular in origin.  Most of our body weight results from muscle mass, considerably less mass is invested in bone, and a very small portion is invested in nerve tissues.  Muscle tissue is under constant stress.  When contracting, the muscle is most metabolically active, and damage can result from constant or long-standing stress/strain, avulsion at the origin and insertion, and damage to connective tissues, ligament, tendon & aponeurosis.

Muscle is also vulnerable to damage when passively stretched, compressed and bent.  All of these activities are regular events to muscle tissue. The symptoms of muscle pathology are rarely well localized by the body.

The intervertebral disc has been suspected as a potential cause of spinal pain, low back, thoracic and neck pain. Anatomic studies have shown multiple pain-mediating nerve fibers distributed throughout the outer part of the spinal disc. Over time, the intervertebral disc can become damaged due to trauma (injury), degeneration from the aging process, as well as from a number of infectious, cancerous, and metabolic reasons. All of these processes can result in pain coming from the spinal disc.

Unfortunately, routine X-ray techniques, MRI, CAT scan and bone scan may show the presence of disk "abnormality," these X-ray studies cannot ensure that the disk "bulge" or herniation is actually causing pain. In fact, recent studies have demonstrated that many people who have never had severe back pain can have disk "abnormality" such as bulge or herniation. The net result is that a great many individuals get their spinal disc's operated upon, only to find that the situation remains unchanged, or the pain may well worsen, resulting in "Failed Back Syndrome."

The diagnosis of "FAILED BACK SYNDROME" is often associated with life-long pain and disability. The best surgeons truly consider spinal surgery to be a procedure to be employed only if less risky approaches fail.

FAILED BACK SYNDROME:

Pain that results from spinal disc disease runs through a number of rather small, delicate nerves. Unfortunately, the pain that results from spinal disc pathology is poorly localized by the brain, and it takes a bit of investigation to carefully identify the precise nerve tissue that is contributing to an individual's pain.

The small nerves that serve the spinal joints, include the sinuvertebral nerves, which innervate the outer third of the fibrous spinal disc, nerves to the Zygoapophyseal Joints and the Joints of Luschka, as well as the median branch of the intraspinous segment arising from the dorsal root ganglion.

Often, X-ray scanning techniques will reveal a "bulge" or "normal" spinal disc. However, these "normal" spinal discs may be causing pain due to slow degeneration of the fibrous outer disc, which can eventually result in frank herniation of the disc. Just as often, the degeneration will slow, the fibrous tissue will harden, but pain can persist. Internal disruption of the spinal disc can cause tremendous pain, and yet the most advanced X-Ray scanning techniques will fail to demonstrate the structural problem 1. Evaluation of internal disc pathology may be best diagnosed with a technique known as "DISCOGRAPHY."

In the recent past, the only X-ray methods useful for imaging the spine were the myelogram, CAT scan and MRI. Myelogram is the technique whereby a needle is placed in to an area where an X-ray dye can be injected, such that it mixes with spinal fluid. The purpose was to provide a medium that would give clear outlines of the nerve roots, spinal cord and disc material. The technique was often painful, complications that could result from the puncture itself include post puncture or post myelogram headache, irritation or arachnoiditis from the dye, and spinal nerve root injury. Unless the injured spinal disc was putting substantial pressure on the spinal cord or roots, internal or structural problems with the disc were missed, the patient was often told that the "pain was in his/her head," and further diagnostic or therapeutic endeavors would end. Many patients suffer from degeneration of the spinal disc without intrusion on the spinal canal, and these patients may only be diagnosed with the technique of "discography."

DISCOGRAPHY

Discography is a technique that allows the physician to gather data as to the presence or absence of damage to the spinal disc that might not be visible with routine scanning techniques. The discography technique involves the introduction of radiologic "dye" to the soft, inner portion of the spinal disc, and the flow of the dye will demonstrate "internal" disruption, or damage that could well be causing the spinal pain.

After the patient is given a light sedative and an anti-biotic may be used, a needle is introduced through the skin and enters the spinal disc, at an angle, thereby avoiding nerve tissue. This is done using a fluoroscope, or X-ray guidance.

The radiologic dye is introduced through a thin needle, directly into the center of the disc. If an internal disruption is present, it will be evident at that time. If the patient experiences reproduction of the pain symptoms as the dye is injected, this immediately demonstrates that the disc is a factor in the patient's complaint of pain.

ANESTHESIA

The discography procedure is done with the patient awake, which is the only way that it should be done safely. An intravenous catheter is most often used to deliver a sedative, which minimizes the discomfort of the procedure.

RISKS

There are no "riskless" procedures in medicine, and every activity of life is associated with some assumed risk. With discography, the principle risk is that of infection, as it is with many procedures that use needles and injections. Anti-biotics are often used to prevent this potential complication.

Bleeding and bruising are possibilities, although most often, they represent more of a nuisance than a substantial risk. The possibility of damage to nerve or spinal tissue is minimized or nearly eliminated through the use of the fluoroscope, or X-ray guidance.

DISCOGRAPHY IS NOT A PROCEDURE THAT A LARGE NUMBER OF SPECIALISTS ARE TRAINED TO PERFORM.  IT IS ESSENTIAL THAT THE PATIENT ASK FOR A PHYSICIAN WELL-TRAINED IN THIS TECHNIQUE.

REFERENCES:

Schwarzer, AC, Aprill CN, Derby R, Fortin J, Kine G, and Bogduk N: The prevalence and clinical features of internal disc disruption in patients with chronic low back pain.  Spine 20:1878-1883, 1995.

David S. Klein, MD, FACA, FACPM, FACMIMS
Director, Pain Center of Orlando
www.suffernomore.com