In 1972, in response to vigorous lobbying by chiropractors, Congress enacted a law providing for limited coverage of chiropractic services under Medicare. The law, which took effect in 1973, called for payment for the treatment of “subluxations demonstrated by x-rays to exist.”  A New York Times editorial called the enactment of Medicare coverage “the most shocking victory for special-interest lobbyists” and added that “the scientific basis of the chiropractic cult is highly dubious.” 
A few weeks after the law was passed, Doyl Taylor, head of the AMA Department of Investigation, told me that when chiropractic inclusion appeared inevitable, the “subluxation” language was inserted with the hope of preventing chiropractors from actually being paid. The idea’s originator thought that since chiropractic’s traditional “subluxations” were visible only to chiropractors, this provision would sabotage their coverage. After the law was passed, however, two things happened to enable payment. First, chiropractors held a consensus conference that redefined “subluxations” to include common findings that others could see. Second, according to Taylor, the government officials responsible for interpreting the new law “decided that Congress intended chiropractors to be paid for something.” The regulators then defined subluxation as “an incomplete dislocation, off-centering, misalignment, fixation, or abnormal spacing of the vertebrae demonstrable . . . to individuals trained in the reading of x-rays.” and stipulated that the “primary diagnosis” must be a subluxation.
The consensus conference, held in Houston in November 1972, resulted in the following statement:
A subluxation is the alteration of the normal dynamics, anatomical or physiological relationships of contiguous articular structures. In evaluation of this complex phenomenon, we find that it has-or may have-biomechanical, pathophysiological, clinical, radiologic, and other manifestations .
The American Chiropractic Association included the Houston “definition” its Basic Chiropractic Procedural Manual, the first edition of which was issued in 1973. The book noted:
Through the years there have been numerous concepts within the chiropractic profession of what constitutes a subluxation. Each of these has had its own rationale and each has had certain validity that has been a contribution to our understanding of this complex phenomenon.
The advent of chiropractic inclusion in Medicare has brought the absolute necessity for a uniform methods of describing, documenting, and reporting spinal subluxations so that those who will administer the law will not be confused by the present lack of uniformity and differences in reporting terminology, to our detriment .
The manual also noted that the conferees had assembled to concur upon a definition that would be “agreeable to all chiropractors while understandable to nonchiropractors; would encompass our understanding so that we would not have improper limitations on us, but would be simple enough for lay interpretation.”
The resultant “definition, several pages long, described the supposed radiologic manifestations of 18 types of “subluxations,” including “flexion malposition,” “extension malposition,” “lateral flexion malposition,” “rotational malposition,” “hypomobility” (also called “fixation subluxation”), “hypermobility,” “aberrant motion,” “altered interosseous spacing,” “foraminal occlusion,” scoliosis, and several conditions in which “gross displacements” are evident. Some are fancy names for the minor degenerative changes that occur as people age; they often have nothing to do with a patient’s symptoms and are not changed by chiropractic treatment. Some, as acknowledged by the Houston conferees, are not even visible on x-ray films. Labeling them “subluxations” was simply a device to get paid.
In the early 1960s, when the National Association of Letter Carriers Health Plan included chiropractic, it received claims for treatment of cancer, heart disease, mumps, mental retardation, and many other questionable conditions. In 1964, chiropractors were asked to justify such claims by sending x-ray evidence of spinal problems. They submitted hundreds, all of which supposedly showed subluxations. When chiropractic officials were assembled to review them, however, they were unable to point out a single subluxation . Following this incident, the plan stopped covering chiropractic services. Referring to these events as an “unfortunate debacle which almost destroyed chiropractic credibility in Washington,” the 1973 Basic Chiropractic Procedural Manual cautioned, in italics, “The subluxations must be perfectly obvious and indisputable.”  These strategic comments were omitted from revised versions of the manual published in 1977, 1980, and 1984.
A 1986 report from the U.S. Department of Health and Human Services’ Office of the Inspector General (OIG) revealed that chiropractic manipulation had been the ninth most frequently billed procedure under Medicare Part B during 1983. The report was based on telephone discussions with 145 out of 200 chiropractors randomly selected from lists provided by insurance carriers. The report noted:
The Medicare Carriers Manual . . . presents a system for classifying subluxations . . . and a system for relating various symptoms to a particular area of the spine. The manual also lists examples of conditions for which manual manipulation of the spine is not an appropriate treatment. Some critics have suggested that this system has provided a blueprint for chiropractors to work backward to identify the appropriate location of a subluxation for billing purposes, as opposed to treating and billing for a subluxation which has been identified on an x-ray .
Sections III and IV of the OIG report were especially critical:
A Conspiracy of Silence?
The OIG investigators concluded that the Medicare x-ray requirement “is not corrently well enforced, may be unenforceable, and is highly conducive to abuse.” Noting that chiropractors were lobbying to remove the x-ray requirement for justifying their services, the report warned that the financial impact of such a law would be great. Chiropractors finally got their wish in 1997, when Congress quietly amended the law to permit payment for subluxations diagnosed by other means — a policy scheduled to take effect on January 1, 2000.
Chiropractors responding to a 1995 American Chiropractic Association Survey reported an average gross 1996 income of $228,236, with 8% from Medicare Part B and 1% from Medicare HMOs, which would add up to about $20,500 per chiropractor . Since 1973, Medicare has paid billions of dollars for treating chiropractic “subluxations.” Yet, as far as I can tell, neither Congress nor the American media have investigated what these dollars have bought.
- Social Security Amendments of 1972 (Public Law 92-603), October 30, 1972, pp. 123-134.
- Health policy paradox (editorial). The New York Times, November 18, 1972.
- Schafer RC, editor. Basic Chiropractic Procedural Manual, Fourth Edition. Arlington, VA: American Chiropractic Association, 1984.
- Schafer RC, editor. Basic Chiropractic Procedural Manual, First Edition. Arlington, VA: American Chiropractic Association, 1973.
- Deely JP. Report of director, health insurance, to the officers and delegates of the forty-fifth national convention of the National Association of Letter Carriers. August 1966, p. 53A.
- Moran WC and others. Inspection of Chiropractic Services Under Medicare. Chicago: OIG Office of Analysis and Inspections, 1986.
- Goertz C. Summary of the 1997 ACA annual statistical survey on chiropractic practice. Journal of the American Chiropractic Association 35(11):30-34, 1998.
This article was posted on November 22, 1998.