A Critical Look at Chiropractic Biophysics (CBP)

Stephen Barrett, M.D.

Chiropractic Biophysics® (CBP®)—sometimes referred to as Clinical Biomechanics of Posture®—is a variation of straight (subluxation-based) chiropractic whose overall goal is to "restore posture." procedures claimed to correct posture [1]. It is taught primarily through seminars sponsored by its founder. The method is based on the questionable idea that postural analysis is valid for diagnosing ligament contractures, muscle weakness, and proprioceptive deficits. (Proprioceptors are sensory receptors, found mainly in muscles, tendons, joints, and the inner ear, that detect the motion or position of the body by responding to stimuli arising within the organism.) The assumed deficits are alleged to decrease blood flow, which decreases oxygen delivery and causes the gamut of disease.

CBP is based on the questionable idea that spinal curvatures that deviate from a mathematically derived "ideal" value should be corrected. According to three of its its leaders:

The overall goal of CBP technique is to restore normal three-dimentional posture. . . . In CBP, the overall posture or global positioning of the spinal column is targeted for correction, as opposed to individual segments.

In CBP, the optimum static position of the upright spine is established with the Harrison spinal model. A subluxation is considered to be any postural deviation from this mathematical norm [1].

To determine what curvature exists, practitioners draw many lines on the patient's x-ray films and measure the various angles at which they meet [1,2]. The treatment centers around the concept of "mirror image adjusting," which is accomplished by "passing the patient's abnormal posture through the normal position and stressing it into its mirror image or exact opposite posture." [3]. The 2000-2001 Chiropractic Biophysics Practitioners Referral List booklet listed about 1,300 chiropractors who had attended a CBP seminar within the previous two years.

To qualify for treatment, patients undergo a postural examination and are screened for contraindications to manipulation and cervical extension traction [2]. Treatment for qualified patients begins with "relief care" consisting of 1-12 sessions of spinal adjustments, cold or hot packs, trigger point therapy for muscle spasms, and/or massage with a motorized table—all of which are commonly used by chiropractors who are not CBP practitioners. When "relief care" ends, CBP practitioners switch patients to "rehabilitative care," which consists of weekly mirror image adjustments, neck and low-back extension traction, and "mirror image" exercises intended to modify spinal curvature over a longer period of time [3]. Initial "rehabilitative" plans often last 6 to 12 months, after which patients are switched to monthly visits for life [4].

Background History

CBP was founded by Donald D. Harrison, a chiropractor who also has a PhD in applied mathematics and a master's degree in mechanical engineering. CBP's origins lie in another technique called Pettibon, which Harrison learned while attending the Western States Chiropractic College. In this system, chiropractors use side-view x-rays of the neck to gauge its alignment and then try to change that alignment using drop-table adjustments. The method differs from traditional chiropractic in that it focuses on alignment of groups of vertebrae rather than individual ones. But it resembles traditional chiropractic in that it considers any deviation from its alleged mathematical norms to be a "subluxation" that should be treated [5].

After graduating from chiropractic college, Harrison taught Pettibon technique until he had a falling out with Dr. Pettibon. As described in Chiropractic Biophysics Online:

What happened in 1980 to steer me away from Pettibon and towards the new technique CBP®? Two things: 1) I discovered Postural Mirror Image Adjusting and 2) Pettibon refused to pay me around $2,500 that he owed me for teaching half (one weekend out of two) of a seminar at Cleveland Chiropractic College LA.

In the summer of 1980, Pettibon asked me to teach the first weekend of his seminar at CCCLA in November for expenses plus half of the profits. I agreed to it because I was only 10 months in practice (just breaking even on overhead) and had no money to get some X-mas presents for my kids. In the first week of December 1980, he sent me a check for $45, which of course did not come close to reimbursing my airfare, motels, meals, and cab rides, not withstanding my supposed half of 65 people X $100 = $6500 income (minus some airfares, motels, meals).

When I called him on it, he said that was "how the numbers came out". I told him that if he didn't pay me for at least my expenses that I would not teach or write for him again. He told me that he never needed me anyway and hung up. With tears in my eyes (my guru just screwed me!), I told Deanne what Burl had said. She asked why I would waste energy over a person who valued a few dollars above my friendship, expert teaching, and writing. She was right and I quit following a guru and started concentrating on science.

A few days later (still Dec 1980), Deanne, Dan Murphy and I met to discuss beginning a new technique, which we all agreed to call CBP (CBP = Physics applied to Biological organisms and it will be Chiropractic). This new technique would be developed from the new posture adjusting that I was discovering [6].

In CBP, Harrison began considering patient posture in addition to x-ray measurements. He says this was necessary because he found that the chiropractic biomechanics of the time was incomplete and oversimplified. Traditional chiropractic analysis is based on the idea that a x-ray image of the spine is a valid method for documenting its position. Harrison concluded that this was not true because one x-ray image could be caused by three different postures and yield false-positive findings that lead chiropractors to treat nonexistent problems [7]. He then created and marketed a technique that he alleged would correct these errors and improve outcomes, changing chiropractic internally through research [8-12]. Harrison also publishes a quarterly newspaper called The American Journal of Clinical Chiropractic, which he uses to promote CBP.

Dogmatic Assertions

Harrison clearly subscribes to a version of chiropractic dogma that most human disease is caused by biomechanical problems of the spine. In 2003, his Web site stated:

To begin, one must first examine the basis for all cellular disease. It is lack of oxygen at the cellular level that creates distress and ultimately, cellular death. Oxygen is normally carried to the cells through the blood in the body. The body's control system for the blood then becomes of major significance. We in chiropractic understand that the nervous system controls all major functions in the body, including the blood vascular system. It is more specifically, the sympathetic portion of the autonomic nervous system that exists as the neurogenic control of the blood supply to the tissues. . . .

As chiropractors, we have a large influence on this process. Chiropractic Biophysic's objective is to correct the posture, thereby alleviating the abnormal loading and the associated nocioceptive impulses. In addition, the effect of the CBP protocol of mirror image adjusting and extension traction creates corrective proprioceptive information into the spinal cord. As previously noted, the conduction velocity of proprioceptive information overrides and effectively inhibits nocioceptive impulse at the spinal cord.

The mirror image adjustment resets the proprioceptive reflexes, inhibits the nocioceptive impulses and corrects the abnormal loading setting up the subluxation. In so doing, the reflex response of vasoconstriction to the viscera is removed and improved vascular tone to the smooth muscle, cardiac muscle and glands, results. The history of chiropractic success with patients experiencing such conditions as asthma, angina, visual disturbances, and other visceral conditions, is now clearly understood [13].

Simply put, according to the above, spinal problems cause decreased blood flow, which causes disease; and CBP increases blood flow to remedy the problems. Similarly, CBP chiropractors commonly suggest that any deviation from the Harrison Spinal Model ideal value will inevitably lead to a degenerative disease process that will adversely affect their health by impairing joint position sense, causing osteoarthritis, herniating spinal disks, and/or putting tension on the spinal cord and nerve roots [14-16]. CBP posters include one called "Neck Curve Decay," another called "Low Back Curve Delay," and another called "Posture Decay," which states: "To live a long active energetic life, few things matter more than good posture."

As far as I can tell, CBP is not discussed in any of the chiropractic textbooks that most chiropractic colleges require. It is taught as an elective at a few colleges and as a required 33-hour course at Life College West, which uses two of Harrison's self-published books as texts.

CBP is advocated for children as well as for adults. The leading advocate is Jennifer Brandon Peet, DC, who practices "chiropractic pediatrics" in Vermont and is a "certified CBP instructor." Peet recommends frequent postural evaluations and "corrective adjustments" that begin at birth. Her book Pediatric Chiropractic Practice Management states that, "Over the years we have used various techniques, but none rival the results we have obtained with Chiropractic Biophysics." [17]. Her 1992 Chiropractic Pediatric and Prenatal Reference Manual devotes about 50 pages to postural analysis, x-ray analysis, and mirror image adjusting. She claims that "even at birth, the infant's vertebral position may be measured relative to a normal model and corrective care may begin by applying a controlled force to reposition the vertebra."[18]. The picture at the right shows how CBP's electrically powered mallet is used to deliver the force to a child's topmost neck bone.

 

Serious Concerns

CBP analyses can accurately and reliably describe a patient's posture. However, its practitioners use this information to make questionable diagnoses of shortened ligaments and proprioceptive problems that require prolonged and expensive treatment.

Chiropractic researcher Gary A. Knutson, DC, has criticized the CBP model as being anatomically and physiologically flawed. In comments in a chiropractic forum, he noted that CBP considers certain degrees of spinal curvature abnormal [19-21] even though other studies have concluded that they are normal [22,23]. He also challenged the CBP assumption [24] that decreased neck curvature is pathologic and requires correction whether or not the patient has symptoms. One study he cited was a 10-year follow-up of neck x-ray findings in patients who had no symptoms. The study found no relationship between the loss of neck curvature and the development of pain or degenerative changes [25,26]. Knutson astutely asked, "If loss of cervical lordosis does not result in any recognizable pain/pathology over a time frame of as long as ten years, by what criteria is such a loss—by itself—necessary to treat?" [27]

The CBP Web site lists more than 75 "research" papers that have been published in journals listed in the Index Medicus [28]. About two-thirds of these appeared in the Journal of Manipulative and Physiological Therapeutics, which is chiropractic's leading journal. Many of the studies concluded that CBP's diagnostic procedures can produce consistent results, and some reported that CBP treatment methods can influence spinal curvature. However, consistency is not the same thing as validity. None of the listed studies demonstrates that patients treated with CBP felt or functioned better as a result of anything unique to CBP treatment.

Mitchell Haas, DC, another prominent chiropractic researcher, agrees that changes in spinal structure do not necessarily cause symptoms. In a blistering review, he stated that CBP advocates have failed to (a) establish the biological plausibility of what they consider an ideal spine, (b) demonstrate that their diagnostic tests enable better patient management, (c) demonstrate meaningful outcomes such as decreased pain or disability, and (d) validate the routine use of spinal x-rays to measure "spinal displacement." Referring to a 1998 paper by Harrison and colleagues, Haas concluded:

The authors' failure to link spinal displacement with any clinical condition (defined in terms of a constellation of measurable and relevant signs and symptoms) makes spinal displacement analysis vulnerable to false-positive diagnoses. It may place patients at risk not only from unnecessary radiation exposure but also from the unnecessary treatment of benign segmental displacement and alternation of spinal curvature. . . .

Harrison et al base their promotion of radiographic displacement analysis on an ideal spine model that fails to account for the variability, adaptability, and functional capacity of the human musculoskeletal system. The authors do not conduct a formal review of the literature; they overinterpret the presented evidence and ignore a body of evidence that refutes claims made for the usefulness of displacement analysis. They also ignore serious risks and limitations of these procedures. Most importantly, the authors identify no clinical entities requiring clinical management associated with radiographic displacement analysis, and they fail to present any credible evidence for the validity, reliability, clinical utility, and appropriateness of these invasive and expensive radiographic procedures they advocate. . . . There is currently no justification for the routine use of radiographic spinal displacement analysis in clinical practice [29].

The picture to the right shows one type of traction-extension device that CBP practitioners use in an attempt to "restore the curve" in people with a flat or reversed cervical curve. Forced hyperextension of this type may be dangerous as well as futile. Samuel Homola, DC, author of Inside Chiropractic, has reported seeing patients treated by such "traction" develop neck pain that was not previously present [30]. Other CBP equipment includes a Lumbar Traction Unit, a Standing Sagittal Traction Unit, and an electrically powered mallet used to apply force to the patient's spine.

 

The CBP Web site states that as of January 2002, there were no published clinical trials supporting 6-month or 1-year programs of care and that "USA State Boards and Canadian Provincial Boards are beginning to bring DCs up on charges of over utilization for extended care programs and for the use of x-ray as a diagnostic tool for evaluating presence and amount of subluxation." The Harrisons have expressed hope that they can do a study that will validate the use of CBP programs that last one year or longer [5].

The Bottom Line

Patients visiting CBP offices typically receive boilerplate examinations to determine whether their spinal curvature is "ideal." They are also advised to have x-ray examinations of their entire spine even if they have no symptoms justifying such tests. Patients may expend considerable time and money for treatment that has not been shown to be more effective than a few manipulations to the areas related to their symptoms. And some will wind up with unnecessary long-term care that includes excessive exposure to radiation.

The first version of this article was drafted in 2003 by Allen Botnick, D.C., who had attended CBP courses and used CBP during his clinical work as a chiropractic student. In 2005, Dr. Botnick developed doubts about some of his conclusions and asked me to remove the article from Chirobase. Rather than do that, however, I have removed the passages referring to his personal experiences and opinions. This revision retains my own beliefs based on close examination of the cited source materials.

References

  1. Harrison DD, Troyanovich S., Payne MR. Chiropractic Biophysics Technique. Chiropractic Biophysics Online, accessed Aug 6, 2003. [Removed after this article was first published.]
  2. Harrison DD. Chiropractic: The Physics of Spinal Correction, CBP Technique. Self-published manual, 1994, pp 11:6, 14:26.
  3. Mirror image adjusting basics. Chiropractic Biophysics Online, accessed Nov 24, 2003. [Removed after this article was first published.]
  4. Harrison DE, Harrison DD. The Lumbar Spine: Structural Assessment and Rehabilitation, The Chiropractic Biophysics (CBP) Approach. Self-published manual, 1998.
  5. Harrison DD. Protocol of care. Chiropractic Biophysics Online, accessed Oct 9, 2003.
  6. Harrison DD. Origins of CBP technique: Part I. Chiropractic Biophysics Online, accessed Oct 9, 2003.
  7. Harrison DD. Origins of CBP technique: Part II: My Discovery of Mirror Image Adjusting. Chiropractic Biophysics Online, accessed Oct 9, 2003.
  8. Harrison DD and others. Torque: An appraisal of misuse of terminology in chiropractic literature and technique. Journal of Manipulative and Physiological Therapeutics 19:454-462., 1996.
  9. Harrison DE and others. The sacroiliac joint: A review of anatomy and biomechanics with clinical implications. Journal of Manipulative and Physiological Therapeutics 20:607-617, 1997.
  10. Harrison DE and others. Three-dimensional spinal coupling mechanics: Part II. Implications for chiropractic theories and practice. Journal of Manipulative and Physiological Therapeutics 21:177-186, 1998. Erratum in: Journal of Manipulative and Physiological Therapeutics 21(4):inside back cover, 1998.
  11. Troyanovich SJ and others. Motion palpation: it's time to accept the evidence. Journal of Manipulative and Physiological Therapeutics 21:568-571, 1998.
  12. Harrison DD and others. Torque misuse revisited. Journal of Manipulative and Physiological Therapeutics 21:649-655, 1998.
  13. Somatoautonomic reflexes, Chiropractic Biophysics Online, accessed Oct 9, 2003. [Removed after this article was first published.]
  14. Cord and brain stem tension. Chiropractic Biophysics Online, accessed Oct 9, 2003. [Removed after this article was first published.]
  15. Questions and answers typically asked by DC's and fellow students. Chiropractic Biophysics Online, accessed Nov 21, 2003. [Removed after this article was first published.]
  16. Harrison DE. A normal spinal position: It's time to accept the evidence. Journal of Manipulative and Physiological Therapeutics 23:623-644, 2000.
  17. Peet JB, Peet PM. Pediatric Chiropractic Practice Management. Burlington VT: The Baby Adjusters, Edition 3, 1993, p 31.
  18. Peet JB. Chiropractic Pediatric & Prenatal Reference Manual. South Burlington VT: The Baby Adjusters, Edition 2, 1992.
  19. Harrison, DE and others. Increasing the cervical lordosis with chiropractic biophysics seated combined extension-compression and transverse load cervical traction with cervical manipulation: Nonrandomized clinical control trial. Journal of Manipulative and Physiological Therapeutics 26:139-151, 2003.
  20. Harrison DE and others. A new 3-point bending traction method for restoring cervical lordosis and cervical manipulation: a nonrandomized clinical controlled trial. Archives of Physical Medicine and Rehabilitation 83:447-53, 2002.
  21. Harrison DD and others. Comparisons of lordotic cervical spine curvatures to a theoretical model of the static sagittal cervical spine. Spine 21:667-675, 1996.
  22. Gore DL and others. Roentgenographic findings of the cervical spine in asymptomatic people. Spine 6:521-54, 1986.
  23. Owens EF, Hoiriis K. Cervical curve assessment using digitized radiographic analysis. Chiropractic Research Journal 1(4):47-62, 1990.
  24. Troyanovich SJ and others. Structural rehabilitation of the spine and posture: rationale for treatment beyond the resolution of symptoms. Journal of Manipulative and Physiological Therapeutics 21:37-50, 1998.
  25. Gore DR. Roentgenographic findings in the cervical spine in asymptomatic persons: A ten-year follow-up. Spine 26:2463-2466, 2001.
  26. Gore DR. Letter to the editor. Spine 27:1249-1250, 2002.
  27. Knutson GA. CBP Discussion. Chiroweb discussion forum, May 20, 2003.
  28. Harrison S. Chiropractic research projects go full time. Chiropractic Biophysics Online, accessed Nov 23, 2003.
  29. Haas M and others. The routine use of radiographic spinal displacement analysis: A dissent. Journal of Manipulative and Physiological Therapeutics 22:254-259, 1999.
  30. Homola S. Inside Chiropractic: A Patient's Guide. Amherst, NY: Prometheus Books, 1999.

This page was revised on August 29, 2005.

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