Four Recent Studies, Using Unique Assessment Approaches, Assess the Safety of Spinal Manipulation for the Treatment of Musculoskeletal Conditions
William H. Kirkaldy-Willis, MD, (1914-2006) was a pioneer in the understanding and treatment of spinal problems. In his life, he published 73 articles that are in the United States National Library of Medicine, and he authored four editions of the medical text Managing Low Back Pain. His other noted accomplishments include:
Dr. Kirkaldy-Willis’ greatest contribution to spine care was advancing the understanding of the “degenerative cascade,” including the pathology and pathogenesis of lumbar spondylosis and stenosis, instability of the lumbar spine, and lateral recess spinal nerve entrapment. In addition, he recognized and advocated for the inclusion of chiropractic spinal manipulation and exercise in the management of low back pain (1).
Thirty years ago, in 1985, Dr. Kirkaldy-Willis was the lead author of a study published in the journal Canadian Family Physician (2), titled:
“Spinal Manipulation in the Treatment of Low back Pain”
In this study, Dr. Kirkaldy-Willis notes that spinal manipulation is one of the oldest forms of therapy for back pain, and that it has mostly been practiced outside of the medical profession. He further notes that there has been an escalation of clinical and basic science research on manipulative therapy, which has shown that there is a scientific basis for the treatment of back pain by manipulation.
Dr. Kirkaldy-Willis discusses how the key to successfully managing chronic low back pain is through the utilization of applied motion. He categorizes applied motion into three groups:
1) Active Range of Motion
This range is achieved through active exercise.
2) Passive Range of Motion
Beyond the end of the Active Range of Motion of any synovial joint, there is a small passive range of mobility. A joint can only move into this zone with passive assistance. Going into this Passive Range of Motion constitutes mobilization, not manipulation.
3) Paraphysiological Range of Motion
At the end of the Passive Range of Motion, an elastic barrier of resistance is encountered. This barrier has a “spring-like end-feel.” When motion separates the articular surfaces of a synovial joint beyond this elastic barrier, the joint surfaces suddenly move apart with a cracking noise. This additional motion can only be achieved after “cracking” the joint and has been labeled the Paraphysiological Range of Motion. This constitutes manipulation. Spinal manipulation is an assisted passive motion applied to the spinal facet joints that creates motion into the Paraphysiological Range. Dr. Kirkaldy-Willis states:
“Spinal manipulation is essentially an assisted passive motion applied to the spinal apophyseal and sacroiliac joints.”
At the end of the Paraphysiological Range of Motion, the limit of anatomical integrity is encountered. The facet joint capsular ligaments create the limit of anatomical integrity.
In his 1985 study, Dr. Kirkaldy-Willis presents the results of a prospective observational study of spinal manipulation in 283 patients with chronic low back and leg pain. All 283 patients in this study had failed prior conservative and/or operative treatment, and they were all totally disabled (“Constant severe pain; disability unaffected by treatment.”) These patients were given a two or three week regimen of daily spinal manipulations by an experienced chiropractor. No patients were made worse by the manipulation, yet many experienced an increase in pain during the first week of treatment. Even with this initial increase in pain, Dr. Kirkaldy-Willis emphasized the importance of continuing with manipulative treatment and not stopping treatment. He states:
“In most cases of chronic low back pain, there is an initial increase in symptoms after the first few manipulations. In almost all cases, however, this increase in pain is temporary and can be easily controlled by local application of ice.”
“Patients undergoing manipulative treatment must therefore be reassured that the initial discomfort is only temporary.”
These outcomes and words imply that chiropractic spinal manipulation is safe and it does not cause any injury. The studies presented below quantify these safety issues surrounding chiropractic spinal manipulation for musculoskeletal syndromes.
Dr. Kirkaldy-Willis notes that when applying spinal manipulation, there is, as a rule, an initial increase in local symptoms. He explains this finding by noting that in chronic low back pain cases, there is a shortening of the periarticular connective tissues and intra-articular adhesions may form; spinal manipulations can stretch or break these adhesions, causing the symptoms. He states:
“In most cases of chronic low back pain, there is an initial increase in symptoms after the first few manipulations [probably as a result of breaking adhesions]. In almost all cases, however, this increase in pain is temporary and can be easily controlled by local application of ice.”
“No patients were made worse by the manipulation, yet many experienced an increase in pain during the first week of treatment. Patients undergoing manipulative treatment must therefore be reassured that the initial discomfort is only temporary.”
Safety of Chiropractic Manipulation of the Cervical Spine
A Prospective National Survey
Volume 32(21), October 2007, pp. 2375-2378
Thiel, Haymo W. DC, PhD; Bolton, Jennifer E. PhD; Docherty, Sharon PhD; Portlock, Jane C. PhD (reference #3)
This study is a prospective national survey whose objective is to estimate the risk of serious and relatively minor adverse events following chiropractic manipulation of the cervical spine by a sample from the United Kingdom of chiropractors.
The authors confess that the injury rate for chiropractic cervical spine manipulation is unknown, but is estimated that the injury ranges from 1 in 200,000 to 1 in several million cervical spine manipulations. In order to assess the injury issue, the authors studied 377 chiropractors, 19,722 patients and 50,276 cervical manipulations. This study is the first, large-scale prospective study designed to record serious and minor adverse events following chiropractic manipulation of the neck.
In this study, manipulation was defined as the application of a high-velocity/low-amplitude or mechanically assisted thrust to the cervical spine. Serious adverse events were defined as referred to hospital and/or severe onset/worsening of symptoms immediately after treatment and/or resulted in persistent or significant disability/incapacity. Minor adverse events reported by patients as a worsening of presenting symptoms or onset of new symptoms, were recorded immediately, and up to 7 days, after treatment.
“There were no reports of serious adverse events.”
In agreement with the article by Dr. Kirkaldy-Willis above (2), minor side effects following chiropractic spinal manipulation were more common. The authors state:
“Relatively minor side effects of cervical spinal manipulation, such as neck pain, stiffness and soreness, headache, and tiredness are common in clinical practice.”
“Although minor side effects following cervical spine manipulation were relatively common, the risk of a serious adverse event, immediately or up to 7 days after treatment, was low to very low.”
“Safety of treatment interventions is best established with prospective surveys, and this study is unique in that it is the only prospective survey on such a large scale specifically estimating serious adverse events following cervical spine manipulation.”
“Although minor side effects were found to be relatively common, the risk of a serious adverse event, immediately and up to 7 days after treatment, was estimated to be low to very low in these consultations.”
“On this basis, this survey provides evidence that cervical spine manipulation is a relatively safe procedure when administered by registered U.K. chiropractors.”
“Based on treatment outcomes obtained from 19,722 patients, the risk of a serious adverse event following cervical spine manipulation was estimated to be low to very low; risks of minor side effects, on the other hand, were relatively common.”
Outcomes of Usual Chiropractic:
The OUCH Randomized Controlled Trial of Adverse Events
September 2013; Vol. 38, No. 20, pp. 1723 – 1729
Bruce F. Walker, DC, MPH, DrPH; Jeffrey J. Hebert, DC, PhD; Norman J. Stomski, BHSc (hons), PhD, Brenton R. Clarke, PhD; Ross S. Bowden, M. Mathematics; Barrett Losco, M. Chiropractic; Simon D. French, MPH, BAppSc (Chiro), PhD (reference #4)
These authors note that “Chiropractic therapy is commonly used to manage musculoskeletal conditions in high-income countries.”
This study is a blinded randomized controlled clinical trial. It’s objective was to establish the frequency and severity of adverse effects from short-term usual chiropractic treatment of the spine when compared with a sham treatment group. The authors used 183 adult subjects with spinal pain, aged 20 to 85 years of age:
92 received usual chiropractic treatment
91 received a sham treatment and were told it was chiropractic.
Each participant received 2 chiropractic treatments: 98% had spinal pain for more than 3 months; 75% had spinal pain for more than 5 years. This means that the study participants were chronic spine pain sufferers.
The sham chiropractic treatment used in this study included “detuned ultrasound,” and Activator adjusting device on the lowest setting applied randomly through a tongue depressor.
The authors found that the adverse event rate was essentially the same between real chiropractic treatment and sham treatment. They interpret this as meaning that there is no injury risk from real chiropractic treatment. Specifically, they note:
“Adverse events were common in both the usual chiropractic care and sham groups, but no important differences were seen between the groups and no serious adverse events were reported.”
“The rate of severe adverse events was not different between the groups.”
“No serious adverse events were reported,” such as disc injury, cauda equina syndrome, fracture, and stroke.
“Most adverse events associated with chiropractic treatment are mild, short lasting, and typical of musculoskeletal condition symptoms.”
Most adverse events attributed to chiropractic have been “benign, transient, and typically consisted of increased pain, muscle stiffness, tiredness, headache, and radiating discomfort.” “Less common events were dizziness, nausea, tinnitus, and impaired vision.”
“A substantial proportion of adverse events after chiropractic treatment may result from natural history variation and nonspecific effects.”
“A substantial proportion of adverse events experienced during chiropractic care for spinal pain may be the result of natural symptom fluctuation or from nonspecific effects.”
Most of the adverse events were benign and transitory.
“The results of our study suggest that many adverse events experienced after chiropractic treatment result from either natural history variation or nonspecific effects.”
“Some may view these results as evidence that chiropractic treatment is essentially an entirely benign intervention.”
In agreement with Dr. Kirkaldy-Willis (2) and Dr. Thiel (3) and colleagues above, chiropractic treatment is associated with minor increases in symptoms. However, this study found similar symptomology in patients receiving sham chiropractic, suggesting that the increased symptoms are probably not secondary to the chiropractic treatment, but rather due to the natural history of their condition. An important comment by the authors is:
“Some may view these results as evidence that chiropractic treatment is essentially an entirely benign intervention.”
Risk of Traumatic Injury Associated with Chiropractic Spinal Manipulation in Medicare Part B Beneficiaries Aged 66-99
December 9, 2014 [epub]
James M Whedon, DC, MS; Todd A Mackenzie, PhD; Reed B Phillips DC, PhD; Jon D Lurie, MD, MS (reference #5)
The primary authors from this study are from the Dartmouth Institute for Health Policy and Clinical Practice. This is a retrospective cohort study. The objective of this study was to compare the risk of injury to the head, neck or trunk following an office visit for chiropractic spinal manipulation for neuromusculoskeletal pain, as compared to office visits to a primary care physician. The study subjects were aged 66-99 years.
This study was quite large. It assessed:
This is the first nationwide population-based study in the United States on the risk of injury following chiropractic spinal manipulation. It is also the first study of the risks of chiropractic to focus specifically on older adults, aged 66-99 years.
The cumulative probability of injury was:
The authors state:
“Spinal Manipulation as performed by chiropractors is an effective option for the treatment of certain types of spinal pain and some headaches.”
“The adjusted risk of injury in the chiropractic cohort was lower as compared to the primary care cohort [by 76%].”
“Among Medicare beneficiaries aged 66-99 with an office visit risk for a neuromusculoskeletal problem, risk of injury to the head, neck or trunk within 7 days was 76% lower among subjects with a chiropractic office visit as compared to those who saw a primary care physician.”