SAN FRANCISCO -- One of the major themes of the May '93 American Back Society (ABS) meeting in San Francisco was that the clinical importance of the intervertebral disc had been exaggerated ever since the seminal Mixter and Barr paper of 1934.1 At the '93 meeting, Dr.
Well, dynasties come and go. One need look no further than the case of the Dallas Cowboys, whose elimination from NFL playoff season (as this article goes to press) by a second year expansion team drew this headline from USA Today: "26-17 loss derails Dallas dynasty." Several presenters at the December 12-14, 1996 ABS meeting sounded the clarion for a new "Dynasty of the Disc," with renewed emphasis on those treatment techniques most likely to impact upon it. This symposium provided evidence from both basic science and clinical research to support this point. Part I of my symposium coverage reviews the various presentations related to the intervertebral disc.
Kuslich on Progressive Local Anesthesia
Dr. Stephen D. Kuslich uses a controversial surgical technique called progressive local anesthesia to identify pain generators in low back and sciatica cases. Identifying the pain generators should enable the design of rational and appropriate treatments. An operating microscope is used on an awake but "slightly sedated" patient to dissect down to the pathology, and note the location and degree of pain, especially its similarity to the preoperative pain. After examining 114 consecutive patients with degenerative disc disease in this way, all of whom had documented herniated discs, nerve root compression, and preoperative sciatica, Dr. Kuslich takes strong exception to the old saw by which up to 90% of low back pain is of idiopathic or nonspecific origin.
He has found that fat, ligamentum flavum, lumbar fascia, lamina and facet bones, spinous processes, facet cartilage, uncompressed nerve roots, uninflamed dura, and the nucleus of the disc are remarkably pain insensitive. The normal nerve root is also pain insensitive, at least to gentle mechanical stimulation. Injecting facets probably reproduces symptoms only because the capsule happens to reside close to true pain generators, such as the posterior disc or the inflamed nerve root. Scar tissue is not itself painful, but can bind nerve roots to the walls of the spinal canal, making them more susceptible to compression or traction and thus likely to generate pain. Although joint capsules were tender in 20% of the (usually older) patients, stimulation produced local back pain only and never sciatic pain.
The disc in one-third of cases provokes about as much pain as "cutting hair." In another third, it is mildly pain sensitive and requires no anesthetic during surgery. In the remaining third of cases, the disc is painful and does provoke the preoperative pain. Although the nucleus is not pain sensitive, stimulating the endplate reproduces that severe back pain that patients perceive as nauseating.
Dr. Kuslich is sure that the majority of severe low back pain comes from the disc, mediated by the vagus nerve. When asked to explain the existence of low back pain without discopathy, he said he could not in many cases, but this is not a large percentage of the total cases out there. Buttock pain comes from simultaneous compression of nerve roots and the annulus of the disc. True sciatica comes from compressed, stretched, or inflamed nerves, in which case even mild pressure will reproduce the symptoms. Indeed, If the nerve is blocked, the sciatica is immediately and totally prevented. More pressure maintained for sustained times will produce a more distal pain, probably due to segmental ischemia of the nerve root.
Derby and Provocative Discography
Dr. Richard Derby agreed that the disc and the sacroiliac joints are important pain generators, but only rarely the posterior joints. He described a procedure called provocative discography: the injection of a radiopaque dye into the nucleus pulposus of an intervertebral disc thought to be causing low back pain, especially as a pre-surgical procedure designed to give the surgeon a precise anatomical diagnosis. The dye demonstrates a variety of appearances, ranging from the "cotton ball" appearance of a normal nucleus, to the very diffuse pattern of internal disc disruption, and finally the escaping dye appearance that confirms the herniation.
Discography is not only morphological, but directly provocative in that the injection may increase discal pressures and register pain. Apart from the information provided by the radiological image, the injection of the dye may reproduce the patient's preoperative pain, and do so exactly. Low levels of pressure will only generate pain in damaged discs. Provocative discography can verify if a disc is a pain generator, by pumping it up with contrast material. Although a disc may be so injured that injecting dye cannot increase its internal pressure enough to cause pain, the ability of the disc to take in more than 1-2 cc of fluid already suggests severe disruption. Dr. Derby discussed the "white dot sign" on MRI (as identified by Dr. Charles Aprill): a high intensity zone amidst the annular fibers, indicating fissuring and strongly predicting pain on discographic injection.
Bischopp on the Cyriax Legacy
Here from Belgium for his presentation, "The Cyriax Legacy," Mr. Bischopp worked for seven years as a physical therapist with Dr. Cyriax, and is currently associated with Orthopaedic Medicine International, Belgium. Like Dr. Kuslich, Cyriax did not believe low back pain to be mostly idiopathic, stating that the disc is often involved, either directly or through its impact on other pain sensitive structures like the dura. By his dural concept, 90% of all problems in the low back would be due to a disc protrusion. The nociceptors of the dura mater can produce multisegmental referred pain, aggravated by coughing, sneezing and straining. Although his beliefs remain controversial to this day, many contemporary researchers and clinicians attribute increasing significance to disc pathology not necessarily disc protrusion, as Cyriax emphasized, but that and other types of disc problems as well, including internal disc disruption.
Cyriax believed low back pain to be disco-dural or disco-radicular, and thought the posterior facetal joint to be pain insensitive, as confirmed by Dr. Kuslich. A disco-dural patient may experience referred pain down to the foot, not to be confused with the radicular (sciatic) pain experienced by a disco-radicular patient. According to Mr. Bischopp, Cyriax felt his most important contribution to be a standardized examination of the body's moving parts by a process of selective tension.
McKenzie and the Significance of Extension
Mr. Robin McKenzie has long found his name synonymous with intervertebral disc rehabilitation and the therapeutic value of extension maneuvers. He finds that ABS meetings have permitted him to mingle with PTs, DCs, and other allied health professionals in a supportive manner, minus the usual feelings of mutual suspicion and even hostility. By his own admission, he was very interested to find that chiropractors actually have two "heads" (a slip of the tongue, hastily corrected to "legs"), care about their patients, and are interested to learn about other ways of treating them.
Commenting on the usual low quality of the randomized controlled clinical trials on low back pain, he proposed a "certificate of competency and license to conduct clinical low back trials," which requires a "rudimentary understanding of where the low back is," and "a better than average chance of coming up with something inconclusively equal to a random chance event."
Asked how his many years of experience have led him to make changes in his low back diagnostic and treatment protocols, he answered: "If it ain't broke, don't fix it." His central procedure remains a mechanical evaluation that identifies which body positions "centralize" or "peripheralize" leg pain that accompanies low back pain. It consists of repeated end-range test movements in various directions, which may aggravate, ameliorate, or leave unchanged both low back midline and leg pain. "Peripheralizers" experience increased distal symptoms, whereas centralizers experience decreased distal symptoms. The examination findings immediately dictate the required treatment, which may involve flexion, but more typically extension, lateral flexion, or combinations thereof.3
Mr. McKenzie believes that disruption of discal tissue results from prolonged flexion, which rationalizes why the hyperlordotic position may be beneficial: it produces anterior discal movement. Although until recently the therapist did the patient positioning, repetitive patient generated end-range loading is a newer technique coming in. Recently, chiropractic manipulation and McKenzie treatment were found to be equally beneficial in a randomized prospective study.4
Donelson on Whether a McKenzie Evaluation Can Predict a Discogram
Dr. Donelson has been investigating for some time now whether patient responses to lumbar bending in multiple directions, according to the McKenzie protocol, could predict the discogram. Dr. Donelson's current findings in a prospective study validate his remarks of two years ago, reported then as preliminary findings in this column: "The McKenzie spinal assessment appears to be a dynamic, noninvasive functional evaluation of symptomatic disc pathology."5
In a prospective study, 63 chronic low back patients, in all of whom nonoperative care had already failed, were referred for discograms. They underwent examination by an experienced McKenzie practitioner (blinded as to the patients' history and MRI results), and immediately thereafter received the discogram. The mechanical assessment found 50% to be centralizers, 25% peripheralizers, and 25% to show no change. In addition, 74% of the centralizers had positive discograms, of which 91% were contained (no leakage of dye). Of the peripheralizers, 69% had positive discograms, with only 54% contained. Of those showing no symptomatic change, only 12.5% had positive discograms. It appears that both peripheralizers and centralizers have discogenic pain, but that the centralizers have a competent annulus, whereas the peripheralizers do not. This makes the peripheralizers a more likely candidate for surgery. Dr. Donelson believes that the patients who were unresponsive during the mechanical examination did not have discogenic pain.
From the Bizarre Surgery Department
Dr. James Zucherman is an orthopedic surgeon and director of Saint Mary's Spine Center of San Francisco, one of the first multidisciplinary back centers in the United States. St. Mary's has been a pioneering institution in the development of back school and stabilization exercises, as well as surgical procedures. The latest and perhaps most novel procedure under development is WARP abdominoplasty: wide abdominal rectus plication, further described as "back surgery without surgery." (Plication refers to shortening a structure by surgically taking in its tucks.)
In this technique, the plastic surgeon decreases the mass of the abdominal wall, through a reduction of the expanse between the umbilicus and pubic area. Up to 14 cm of abdominal wall fascia can be plicated and then closed. The indications include a multilevel problem, internal disc disruption or herniation, the finding that abdominal compression with bracing gives relief, and prolonged refractory pain. There is radiographic evidence of increases in intervertebral space, as well as MRI evidence of possible disc reconstitution. Muscle strength evaluation demonstrates a significant increase in transverse abdominis-internal oblique complex strength with surgery alone, prior to the institution of any rehabilitative therapy.
Coming Attractions for Part II
My next column continues coverage of the 1996 meeting of the American Back Society. It discusses each of the following presentations:
- Drs. Greenman, Glassman, and Lippitt each dealt with aspects of the lumbopelvic area, in some ways overlapping and in other ways differing from typical chiropractic considerations.
- Dr. Scott Haldeman spoke on the topic of credentialing of health care providers. After declaring that "managed care is here to stay, whatever you may think," he described how credentialing could potentially ensure the compatibility of patient, doctor, and provider needs. Dr. Haldeman later returned to explain how spinal manipulation is a good example of how outcome-based research can lead to the widespread acceptance of a treatment method.
- Dr. William Meeker, director of the Palmer Center for Chiropractic Research, presented the results of a prospective randomized controlled clinical trial to compare chiropractic management versus physical therapy/exercise management for potential workers' compensation cases involving injuries to the low back.
- Several presenters dealt with aspects of the structure and function of the nervous system. Dr. Arthur Schuller discussed sympathetically maintained pain (SMP), or pain attributable to sympathetic efferent function in peripheral tissues. Dr. Rene Cailliet discussed the neurophysiological basis for back pain. Dr. Silverman conducted a workshop in the electrodiagnostic examination of the nervous system.
- Ms. Erica Gould described Pilates-based exercises for spinal rehabilitation.
- Physical therapist H. Duane Saunders' explained why his primary focus is on restoration and maintenance of function, and specifically not on pain.
- Dr. Jacob J. Parker conducted a particularly compelling workshop on spinal imaging, and then returned to describe the use of sonography to diagnose soft tissue injuries of the spine.
- Dr. Edward Simmons also spoke on advancing imaging of the spine, discussing MRI myelography. This a new technique that makes it technically possible to obtain a myelographic image using MRI, without the need to inject a contrast medium.
- Dr. Andrea Trescott disputed the conventional wisdom that tension headaches usually result from irritation of the greater occipital nerve as it passes through the nuchal fascia. She invokes instead tendinitis of the splenius capitus and/or trapezius muscles, after observing the underlying similarly of tension headache and posttraumatic headache.
- Dr. Lawrence Nordhoff described the mechanism and overall impact on society of motor vehicle accidents.
- Dr. George Becker addressed the topic of somatization, casting doubt on whether it is really possible to distinguish depression from chronic fatigue syndrome and fibromyalgia.
The American Back Society may be contacted at 2647 E. 14th St., Suite 401, Oakland CA 94601, Tel (510) 536-9929, Fax (510) 536-1812. It is possible to obtain audio tapes of all the presentations from this symposium.
References
- Mixter WJ, Barr JS. Rupture of intervertebral disc with involvement of the spinal cord. New England Journal of Medicine 1934;211:210.
- Cooperstein R. Old fashioned competency in history taking and physical examination. Dynamic Chiropr 1993 (August 13):23, 26-27.
- McKenzie RA. The Lumbar Spine: Mechanical Diagnosis and Therapy. Waikanae, New Zealand: Spinal Publications, 1981.
- Cherkin D, Deyo R, Battie M, Street J, Barlow W. A randomized trial comparing chiropractic manipulation, McKenzie therapy, and an educational booklet for low back pain. In: FCER, ed. 1996 International Conference on Spinal Manipulation. Bournemouth, England: Foundation for Chiropractic Research and Education, 1996:103-104.
- Cooperstein R. ABS Fall symposium: The brave new world of managed care, Part 1. Dynamic Chiropr 1995 (February 27):19-20. 30-31.
Robert Cooperstein, MA, DC
Palmer Center for Chiropractic Research
Faculty, Palmer College of Chiropractic West
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