January 2011 Newsletter from Malik Slosberg, DC, MS

Dagenais, S, DC, PhD et al. NASS Contemporary Concepts in Spine Care: SMT for ALBP. The Spine Journal 2010; 10: 918–940.

Lindstrøm R et al. Association between neck muscle coactivation, pain, and strength in women with neck pain. Manual Therapy 2011; 16(1):80-86.
This month's papers provide important contributions to our understanding of the current state of the science concerning chiropractic care and disturbances of motor control. The first study is a thorough systematic review specifically of the relative efficacy of spinal manipulation for acute low back pain versus other recommended interventions in common use today. The findings reinforce what other previous reviews have concluded and provide chiropractors with an evidenced based foundation from which to discuss the value, and appropriate use, and the effectiveness of chiropractic care. The second study is an excellent demonstration of the disturbances in motor control and coordination as a result of chronic pain. In this paper the topic is chronic neck pain, loss of strength, and aberrant function of neck stabilizing muscles. However, its findings are very applicable to disturbances in motor control as result of chronic low back pain. I hope you find the following information helpful.

Dagenais, S, DC, PhD et al. NASS Contemporary Concepts in Spine Care: SMT for ALBP. The Spine Journal 2010; 10: 918–940.

A systematic review (SR) to assess the scientific literature related to the efficacy of spinal manipulation (SM) for acute low back pain (ALBP).

Methods: A MEDLINE search identified 6 randomized controlled trials (RCTs) of SM for ALBP (=/<3 mo) published in English. RCTs included in 2 previous SRs which were also included for a total 2,027 subjects in the 14 RCTs. Studies combined SM with education (n=5 studies), mobilization (MO) (n=4), exercise (n=3), modalities (n=3), or medication (n=2). SM was compared with physical modalities (n=7), education (n=6), medication (n=5), exercise (n=5), MO (n=3), or sham SMT (n=2). SM were most commonly performed by DCs (n=5) & physical therapists (PTs) (n=5). Most studies (n=6) were of 5 to 10 SM visits over 2 to 4 wks.

Outcomes: pain (n=10), function (n=10), health-care utilization (n=6), & global effect (n=5).

Studies had follow-ups of of <1 mo (n=7), 3 mo (n=1), 6 mo (n=3), 1 yr (n=2), or 2 yrs (n=1).

Results for Pain Reduction: SM groups were superior in 3 RCTs & equivalent in 3 RCTs in the short term, equivalent in 4 RCTs in the intermediate term, & equivalent in 2 RCTs in the long term.

Results for Improvement in Function: SM groups were superior in 1 RCT & equivalent in 4 RCTs in the short term, superior in 1 RCT & equivalent in 1 RCT in the intermediate term, & equivalent in 1 RCT and inferior in 1 RCT in the long term. No harms related to SM were reported in these RCTs. Like many manual treatments for ALBP, SM has a diminishing effect as the duration of follow-up increases.

Conclusions: Results assessing the efficacy of SM for ALBP suggest that 5 to 10 treatments over 2 to 4 weeks achieve equivalent or superior improvement in pain and function compared to other commonly used interventions: physical modalities, medication, education, or exercise, for short, intermediate, and long-term follow-up. Clinicians should discuss SM as a treatment option for ALBP patients who do not find adequate symptom relief with self-care and education alone.

Commentary: This new systematic review’s conclusions are consistent with several earlier systematic reviews by prestigious multidisciplinary panels of experts (DCs, MDs, PhDs) going back to 2003. It basically states that SM is at least as effective and sometimes more effective than other conservative interventions with which it has been compared. As Haldeman, S, DC, MD, PhD and Underwood, MD noted in 2010, “there is now little dispute amongst knowledgeable scientists that SM is of value in the management of back pain, neck pain, and headaches that make up 90% or more of all chiropractic patients.” This new data should be of considerable help to chiropractors trying to practice according to thebest scientific evidence, to patients seeking care and trying to decide whether chiropractic is a reasonable option, to other physicians who wish to refer patients to or work closely with DCs, and to policy makers who have to decide what treatments should be paid for. The strength of the findings notifies all health care providers that spinal manipulation is a viable and evidence-based treatment option for ALBP patients and should be considered as an effective mainstream intervention.

Lindstrøm R et al. Association between neck muscle coactivation, pain, and strength in women with neck pain. Manual Therapy 2011; 16(1):80-86.

This new study investigates the relationship between neck muscle coactivation (agonists and antagonists: SCM during neck extension, splenius capitus (SC) during flexion), neck strength, pain & disability in 13 women with chronic neck pain (CNP - average duration 7.1 yrs) & 10 healthy controls.

Methods: Surface EMGs of the SCM & splenius were measured as subjects 1) performed maximum voluntary contractions (MVC) in flexion, extension & lateral flexion, 2) ramped contractions from 0% to 50% MVC in flexion & extension and 3) circular contractions in the horizontal plane.

Results: Higher amplitude EMGs were seen for the SC (antagonist) during neck flexion & for the SCM (antagonist) during extension in CNP patients (Pts). The EMG amplitude of SC during cervical flexion was positively correlated with Pts’ pain & disability. The greater the amount of activation of SC during cervical flexion the less the overall flexion strength.

Findings indicate that alterations in neuromuscular control in CNP Pts are associated with functional consequences: impaired motor performance & increased levels of disability. Experimental pain studies also show a pain induced reorganization of the motor strategy characterized by reduced activity of the agonist muscle & increased activity of antagonist muscles.

Conclusion: Although increased coactivation of the neck muscles may be beneficial in acute pain to enhance cervical stability and stiffness and thereby reduce velocity and ROM, it may also reduce neck strength, as well as, contribute to recurrent pain by altering the load distribution on the spine and irritating pain sensitive structures.

Conclusion: CNP Pts showed an overall reduction of neck strength.

Neck pain Patients maximum strength for sagittal flexion was reduced 31.7%
Reduced in extension 22.6%
Reduced in right lateral flexion 33.2%
Reduced in left lateral flexion 32.2%
Total neck strength was reduced 29.2%

Commentary: This new study is a vivid demonstration of the disturbances and reorganization of motor programs in chronic neck pain patients. The paper indicates that muscle coordination and coactivation are aberrant in neck pain and not only result in reduced overall strength but a reduction in strength in every plane of movement. No wonder these patients hurt. No wonder these patients are vulnerable to recurrent bouts of reinjury, inflammation, and pain with little or no biomechanical stress. Other studies have demonstrated that in such patients there is also increased fatty deposition, a loss of distinct muscle boundaries/delineation, and reduced cross-sectional area in the neck muscles in chronic neck pain. Similar studies have demonstrated very similar deficits in the back muscles of low back pain patients.
So what to do? From a chiropractic perspective there are two methods which have been documented to be helpful:
1. Spinal Manipulation has evidence that it can improve unconscious disturbed stabilizing motor programs and accelerate delayed muscular reflexes necessary to contract, unload, and protect passive ligamentous restraints: ligaments, joint capsules, discs.
2. Exercise training has abundant evidence that it can improve strength, endurance, coordination, accelerate contraction times, and even help improve the function of neuromotor neurons.
There is excellent research to demonstrate the combination of spinal manipulation and exercise enhance the outcomes beyond what either manipulation or exercise offer single interventions. So make your practice evidence based and utilize a combination of spinal manipulation and exercise training.