A Skeptical Look at Chiropractic BioPhysics (CBP)

Stephen Barrett, M.D.
December 8, 2015

Chiropractic BioPhysics® (CBP®)—sometimes referred to as Clinical Biomechanics of Posture®—is a variation of straight (subluxation-based) chiropractic whose overall goal is to “correct posture.” [1] It is taught primarily through seminars sponsored by its founder. Its official Web site describes it as “a more knowledgeable, comprehensive, systematic, scientific approach to chiropractic, that provides predictable results for patients and will contribute to building a more stable and successful chiropractic practice.” [2]

CBP is based on the concept that spinal curvatures that deviate from a mathematically derived “ideal” value should be corrected. As noted by several of its leaders:

The overall goal of CBP technique is to restore normal 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 [1,3]. 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.” [4].

To qualify for treatment, patients undergo a postural examination and are screened for contraindications to manipulation and cervical extension traction [3]. 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 [4]. Initial “rehabilitative” plans often last 6 to 12 months, after which patients are switched to monthly visits for life [5].

Background History

CBP was founded by Donald D. Harrison (1946-2011), a chiropractor who also had 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 he 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.

CBP practitioners 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 [13-14]. CBP is said to aim not just for symptom relief but for structural (subluxation) correction [15]. 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.” CBP’s minimum care program is 6 months.

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.” [16]. 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.”[17]. 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.


Not Well Accepted

The number of chiropractors who practice CBP is unknown, but existing data suggest that the percentage is small. About 68,000 chiropractors are licensed to practice in the United States. During a deposition in 2007, Harrison testified that over the years, a total of about 6,000 had attended his seminars, but not all of them practice CBP. (Presumably, some never used what they learned and others have returned by now.) The 2000-2001 Chiropractic Biophysics Practitioners Referral List booklet listed about 1,300 chiropractors worldwide who had attended a CBP seminar within the previous three years. The February 2009 CBP Online Referral Manual listed 953 who had attended during the previous two years. A pilot survey of chiropractors who graduated from Canadian Memorial College after 1980 found that 4 out of 83 respondents said they had attended CBP seminars and 2 out of 83 said they practiced it [18]. An April 2009 Google search of the Chiropractor Directory Web site (which has separate pages for each city) found that 438 out of about 9,520 cities had at least one CBP practitioner, but not everyone in the directory lists everything they do.

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. The most comprehensive chiropractic text, Scott Haldeman’s Chiropractic Principles and Practice, doesn’t discuss CBP by name but criticized all of the chiropractic systems centered around x-ray marking:.

Chiropractic roentgenomics (the marking of radiographs for spinal malpositions, misalignments, or “subluxations”) has always been controversial within the profession, particularly because the impact of natural and normal asymmetries within the body on these measurements is not known [19].

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 [20-22] even though other studies have concluded that they are normal [23,24]. He also challenged the CBP assumption [25] 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 [26,27]. 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?” [28]

In 2003, the CBP Web sited listed more than 75 CBP “research” papers that were published in journals listed in the Index Medicus [29]. 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 demonstrated that patients treated with CBP felt or functioned better as a result of anything unique to CBP treatment. Since 2003, more papers have been published, but they do not supply the missing information.

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 [30].

The most comprehensive textbook on chiropractic technique systems provides a detailed critique of CBP [31]. It’s findings include:

  • The goal of CBP research is to determine ideal posture, assess the patient’s posture, and use chiropractic care to move patients toward that posture as much as possible.
  • CBP assumes that even slight deviations from that posture will cause adverse mechanical tension and nerve interference.
  • CBP x-ray analyses often conclude that patients with no symptoms still need treatment to modify their spinal curvature.
  • Although CPB studies report modification of spinal curvature, it is not clear whether this is beneficial or even clinically significant.
  • Although the case made by CBP practitioners for rehabilitation protocols seems reasonable enough, obviously the degree of treatment deemed necessary greatly depends on the goal of care. If that goal includes convergence on some spinal structure said to be normal, whereas in fact that goal has not been validated, then the degree of rehabilitation that is appropriate and clinically necessary may also be questioned.
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 [32]. 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.

In 2002, the CBP Web home page announced that as of January 2002, there were no published clinical trials supporting 6-month or 1-year CBP 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 article also expressed hope that suitable studies can be done [2]. The 2002 report is still posted, but as far as I know, no randomized controlled clinical trials have evaluated whether long-term CBP programs have lead to improved health outcome.

In 2005, the Journal of the Canadian Chiropractic Association published two reports by Harrison and his colleagues. One summarized their view of the evidence supporting CBP protocols [33]. The other claimed that the x-ray studies used by CBP pose “essentially no scientifically demonstrable risk to the given patient.” [34] In 2006, four professors who belong to the Association of Chiropractic Colleges’ Chiropractic Technique Consortium tore these articles to shreds. In one article, they pointed out serious flaws in the design, conduct, and analysis of CBP-sponsored research [35]. In a separate article, they concluded:

The . . . commentary is little more than a biased, unscientific and self serving argument for promoting the routine use of radiography by chiropractors. Such promotion, with such inconclusive evidence may be viewed as professionally irresponsible by the scientific and academic community. To insinuate, in addition, that radiation exposure provides more good than harm adds further insult to injury [36].

in 2007, the European Spine Journal published a report of a study in which 107 volunteers aged 45 or older underwent x-ray examination of their neck and were asked about neck pain or disability within the previous year. The authors concluded that the presence of neck curvature in patients with neck pain should be considered coincidental and not necessarily indicative of the cause of pain [37]. In 2008, a systematic review that included 54 studies found ” no strong evidence for any association between sagittal spinal curves and any health outcomes including spinal pain [38]. A subsequent study reported no difference in neck alignment between 29 patients with nonspecific chronic neck pain and 30 healthy volunteers and no significant change in neck alignment after four weeks if neck manipulation. The study’s authors also noted that contrary studies by CBP advocates had been weakly designed [40].

Insurance Coverage

Insurance coverage for practices unique to CBP is limited. Insurance companies do not normally or knowingly pay for treatment considered “experimental and investigational.” Whereas spinal manipulation for back pain is commonly covered, long-term programs that purport to correct spinal misalignments are not. Aetna’s Clinical Policy Bulletins identify such methods and explain the basis for judging them. Regarding CBP, it said:

  • The use of chiropractic to correct abnormal spinal curvature in people without symptoms is considered experimental and investigational.
  • There is insufficient scientific evidence to support the use of CBP.
  • The published peer reviewed literature focuses primarily on explaining the theoretical basis for the Chiropractic Biophysics Technique.
  • There is a paucity of published peer reviewed literature evaluating the effectiveness of the Chiropractic Biophysics Technique in improving clinical outcomes (e.g., reductions in pain and disability, improvements in function). In a 10-year follow-up study of neck x-ray findings in asymptomatic patients, Gore (2001) found no relationship between the loss of neck curvature and the development of pain or degenerative changes.
  • Haas and colleagues (1999) noted that changes in spinal structure do not necessarily cause symptoms. They stated that CBP advocates have failed to (i) establish the biological plausibility of what they consider an ideal spine, (ii) show that their diagnostic tests enable better patient management, (iii) demonstrate meaningful outcomes such as decreased pain or disability, and (iv) validate the routine use of spinal x-rays to measure spinal displacement [40].

In 2006, more than two years after the first version of this article was posted, Harrison issued an e-mail announcement that Aetna and some Blue Cross groups had denied claims because “CBP is experimental” and that two managed care programs (ACN Group and American Specialty Health Network) had denied acceptance of practitioners who utilized CBP Technique. Having concluded (incorrectly) that my article was responsible for this, he asked chiropractors to contribute money to pursue a libel suit [41]. In the Fall of 2006, he filed a suit, which he later described as “the first step in a future law suit against certain insurance providers, who have been using Barrett’s Quackwatch claims to deny chiropractic claims and deny DCs from being in-network providers.” [42] We responded to the suit with a “motion on the pleadings” which pointed out that the statements the suit complained about were my opinions of CBP and did not defame Harrison. The judge agreed, and the dismissal was upheld on appeal [43]. Harrison died in 2011 at the age of 65, reportedly of complications of diabetes [44].

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 or other treatment of the areas related to their symptoms. And some will wind up with unnecessary long-term care that includes excessive exposure to radiation.

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  36. Bussières AE and others. Ionizing radiation exposure – more good than harm? The preponderance of evidence does not support abandoning current standards and regulations. Journal of the Canadian Chiropractic Association 50:103-106, 2006.
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  39. Shilton M and others. Does cervical lordosis change after spinal manipulation for non-specific neck pain? A prospective cohort study. Chiropractic & Manual Therapies 23:33, 2015.
  40. Clinical Policy Bulletin: Chiropractic services. Aetna Web site, revised Oct 26, 2007.
  41. Harrison DD. E-mail to “CBP Practitioners & Chiropractic Friends.” Distributed May 2006.
  42. Help us locate Allen Botnick: Quackwatch lawsuit update. Journal of Clinical Chiropractic, Jan 2007.
  43. Memorandum. Harrison v. Botnick et al. Superior Court of Pennsylvania, No. 1482 EDA 2008, filed March 5, 2009.
  44. The obituary of Dr. Donald D. Harrison. Journal of Clinical Chiropractic, Aug 11, 2011.

This article was revised on December 8, 2015.