Research Review by Dr. Shawn Thistle©

Date:

Feb. 2008

Study Title:

Evidence-informed management of chronic low back pain with spinal manipulation and mobilization

Authors:

Bronfort G, Haas M, Evans R, Kawchuk G, Dagenais S

Authors’ Affiliations: Northwestern Health Sciences University; Western States Chiropractic College; Faculty of Rehabilitation Medicine, University of Alberta; Faculty of Medicine, University of Ottawa

Publication Information:

The Spine Journal 2008; 8: 213-225.

Summary:

Chronic low back pain (CLBP) remains a challenging condition to manage, one that carries a significant socioeconomic burden. There are a plethora of non-surgical treatments for CLBP, which can overwhelm stakeholders such as patients, third party payers, health care providers, researchers, and policy makers. Although all involved should strive for the most effective treatment that utilizes minimal health care resources, there is often clinical uncertainty as to which treatment is most appropriate for the individual patient.

In order to better understand the state of existing literature on non-surgical treatments for CLBP, the North American Spine Society sponsored a special focus issue of The Spine Journal. This review of spinal manipulation/mobilization was one of the papers featured in this issue. An executive summary of background information and pertinent findings will be presented in this review.

Terminology:

For the purpose of this review, spinal manipulation was defined in a standard manner as: the application of a high-velocity, low-amplitude manual thrust applied to the spinal joints “slightly beyond the passive range of motion”. Spinal mobilization was defined as the application of a manual force to the spinal joints within the passive range of motion that does not involve a thrust.

The authors acknowledge that many subtypes of manipulation exist in manual medicine. The most common is called “Diversified”, as it incorporates aspects taught in many of these subtypes. This is the type familiar to most manual therapists. It should be noted that instrument assisted (ex. Activator), and low-force manual procedures were not included for consideration in this review.

Theories Regarding Mechanism of Action:

Many hypotheses exist which attempt to explain how spinal manipulation/mobilization (SMT/MOB) exert their effects. Generally, they focus on either the consequences of applying external forces to the tissue in this spine, or the internal neurological effects of these forces. The former has several studies investigating the immediate effects of SMT/MOB on tissue displacement/deformation including:
  1. altering orientation or position of anatomical structures
  2. unbuckling of structures
  3. release of entrapped structures
  4. disruption of tissue adhesions
It is however, the latter idea of internal neurological effects that has the greatest body of evidence indicating that SMT/MOB impacts primary afferent neurons in paraspinal tissues, the motor system in general, and various pain pathways. The authors emphasize that, at present, the exact mechanism(s) of action for SMT/MOB remain unknown. Although this does not negate their clinical efficacy, it has likely hindered the widespread acceptance of these techniques by the wider scientific and healthcare communities.

Indications and Contraindications to SMT/MOB:

Various countries and organizations have established clinical practice guidelines for the treatment of LBP. In general, the recommended indication for SMT/MOB is non-specific, mechanical CLBP. As such, the authors of this review could only recommend that patients who do not have any of the contraindications listed below are potential candidates for SMT/MOB. Contraindications to SMT/MOB include:
  • ”Red Flags”: fever, unrelenting night pain or pain at rest, pain with below the knee numbness or weakness, leg weakness, loss of bowel/bladder control, progressive neurological deficit, history of cancer, unexplained weight loss
  • fracture
  • osteoporosis
  • trauma causing tissue disruption in the area being treated
The authors briefly mentioned the emerging research on acute LBP (in the form of the LBP Clinical Prediction Rule from Delitto, Fritz, Childs et al.) that has identified characteristics that can help distinguish patients who are more likely to respond favorably to SMT including:
  1. symptom duration < 16 days
  2. no symptoms distal to the knee
  3. FABQ score < 19
  4. hypomobility of one or more segments of the lumbar spine
  5. internal hip rotation > 35° on one or both sides
Results of Literature Review:
  • 42 studies were identified evaluating SMT/MOB for CLBP – 8 more than the most recent large scale review on this topic
  • overall, the literature provides moderate to strong evidence in favor of SMT for mixed (but predominantly chronic) LBP
  • in terms of patient-rated pain, SMT with strengthening exercise is similar to prescription NSAIDs with exercise in the short and long term (moderate evidence)
  • SMT/MOB is superior to usual medical care and placebo for patient improvement (moderate evidence)
  • high-dose SMT is superior to low-dose SMT for pain in the very short term, and similar in the short term
  • flexion-distraction MOB is superior to a combined exercise program for pain in the short term and superior/similar in the long term, and has a similar effect on disability as a combined exercise program
  • for mixed (mainly chronic) LBP, there is strong evidence that SMT is similar to a combination of medical care and exercise in terms of short and long term patient-rated pain and disability
  • there is moderate evidence that SMT is superior to physical therapy and to home exercise in the long-term (bear in mind that many physical therapists do perform SMT)
Harms of Lumbar SMT:
  • SMT is generally a safe intervention – most commonly associated with only benign, temporary side effects including local soreness which typically does not interfere with regular activity
  • rare adverse events associated with lumbar SMT can include lumbar disc herniation (LDH) and cauda equina syndrome (CES) – because of the low incidence, true risk estimates are tough to establish
  • the best available evidence, as summarized by these authors, places the risk of LDH or CES subsequent to lumbar SMT at approximately: 1 event in 3.72 million treatments

Conclusions & Practical Application:

This paper provided a current synthesis of existing literature on the management of CLBP with SMT/MOB. The addition of newer evidence that has emerged since the last major review on this topic has strengthened the evidence regarding the efficacy of SMT/MOB for CLBP.

Future studies should focus on the treatment of well-defined groups of patients, according to reliable and validated diagnostic classification systems such as the LBP Clinical Prediction Rule. This will serve only to strengthen the quality of research in this area, and better guide clinical practice.