Research Review By Dr. Demetry Assimakopoulos©


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Date Posted:

November 2013

Study Title:

Outcomes from Magnetic Resonance Imaging-Confirmed Symptomatic Cervical Disk Herniation Patients Treated with High-Velocity, Low-Amplitude Spinal Manipulative Therapy: A Prospective Cohort Study With 3-Month Follow-Up


Peterson CK, Schmid C, Leemann S et al.

Author's Affiliations:

Department of Chiropractic Medicine, Faculty of Medicine, Orthopedic University Hospital Balgrist, University of Zurich, Switzerland.

Publication Information:

Journal of Manipulative & Physiological Therapeutics 2013; 36: 461-467.

Background Information:

Statistically, 83.2 out of every 100 000 people suffer from symptomatic compression of a cervical nerve root caused by a disc herniation (CDH), degenerative spondylosis, or a combination of the two, with the C6 and C7 nerve roots being most commonly involved. This injury often results in severe pain and disability, due to pain and paresthesia (that could be in a dermatomal pattern), and weakness of the muscles innervated by the involved nerve root.

Patients suffering from symptoms of cervical radiculopathy are often treated with lifestyle changes, activity modifications, pain medications, physical therapy, epidural injections and sometimes spinal manipulative therapy (SMT). Currently, the research does not show sufficient evidence to advocate the use of manipulation as a therapeutic modality in individuals with CDH. In spite of this, many practitioners, namely chiropractors, manipulative physical therapists and other manual therapists, use SMT to help patients with this problem. The purpose of this study was to investigate the clinical outcomes in patients suffering from cervical radiculopathy after a course of care utilizing high-velocity, low-amplitude (HVLA) SMT.

Pertinent Results:

  • Fifty patients were enrolled in the study – 68% were male and the average age was ~44.
  • Two weeks after the first treatment, 55.3% of all patients reported that they had significantly improved. At this point, no one reported worsening of their symptoms.
  • At 1 month after the first treatment, 68.9% of individuals were significantly improved, with only one patient reporting being slightly worse (one patient in the subacute/chronic group).
  • By 3 months, this figure rose to 85.7% of patients noting significant improvement.
  • In general, acute patients reported faster improvement compared to those who were included in the subacute or chronic group.
  • However, 3 months after the first treatment, 76.2% of the subacute/chronic patients reported clinically relevant improvement, with none of these patients reporting they were worse.
  • The acute patients reported statistically significant reductions in their neck and arm pain measured via NRS, as well as their NDI scores at all 3 data points.
  • The subacute/chronic patients had similar results, with the exception of the baseline-2 week data point, where their NRS arm score was not significantly reduced.

Clinical Application & Conclusions:

Most of the patients in this study with MRI-proven cervical disc herniation who were treated with spinal manipulation reported clinically significant improvement at all selected data points, especially at 3 months.

It is important to note that one of the most recent reviews on cervical radiculopathy states that the clinical course of this condition is poorly documented, and that it is impossible to ascertain reliable figures on the natural history of this injury from the very few published studies documenting the progression of acute CDH in patients who have not had any treatment (1). The fact that even the subacute/chronic sufferers showed clinically significant improvement is an important result to report, as it is these patients that are often the most costly to the healthcare system.

This is an important study which adds to the results of prior systematic reviews on this topic (see Related Reviews below). These authors demonstrated that patients with symptomatic, MRI-confirmed CDH can be treated with SMT at the level of herniation, as most patients in this study reported high levels of clinically relevant improvement at all measured data points.

EDITOR’S NOTE: Below is an excerpt from an article I (Dr. Thistle) wrote with Dr. Mark Erwin, a chiropractor/PhD who is one of the world’s leading experts on disc pathology. This article was written for the Canadian Chiropractic Association and discussed this paper, and the other cohort on lumbar disc herniation patients. The information below provides some additional food for thought to go along with this review:

The clinical decision process surrounding the use of high-velocity, low-amplitude (HVLA) spinal manipulation (SMT) in patients with suspected (or confirmed) cervical (CDH) or lumbar disc herniation (LDH) has traditionally been difficult. Clinicians naturally wish to help their patients, yet medicolegal concerns about iatrogenesis or worsening of the patient’s condition while under care are particularly prevalent for these patients. Similar to most spinal conditions, a variety of interventions are commonly employed in the treatment of CDH/LDH. The most effective treatment for CDH and LDH remains largely unknown to date, although it is generally agreed that a course of conservative treatment should be undertaken before surgery is considered. Regarding SMT specifically, the existing clinical evidence has been unable to provide a consistent level of guidance. In the real world, there have certainly been successes and failures.

The genesis of the herniated nucleus pulposus (HNP) is a multifactorial process and the clinician ought to bare these differences in mind when faced with a patient suffering from a HNP. Degenerative changes affecting the intervertebral disc (IVD) include loss of extracellular matrix integrity with the nucleus of the IVD as well as the progressive cell death of NP cells. Tears and fissures also occur throughout the annulus that likely lead to changes in tolerance of applied loads. However, one wonders what the ramifications of these changes are, particularly with respect to the choice of manual therapies. If the hypothesis is that SMT is beneficial to some patients with HNP, what is the mechanism? What does SMT accomplish in the presence of a torn annulus and herniated nucleus pulposus? Or, does this study (and their lumbar spine cohort) actually suggest that the SMT accomplishes anything with respect to the HNP as opposed to manual therapy for ‘mechanical neck pain’ in general (which is reasonable, as many patients did improve under care)? Is any benefit of SMT superior to a placebo? Radiculopathy caused by a herniated NP involves an inflammatory cytokine-induced neuropathy as well as a host of other biochemical and cellular events with the process requiring hours, days, weeks, months or even years to occur. Therefore, we cannot know how long the HNP was present prior to treatment commencing? What might occur through the provision of SMT that could resolve this pathology? These are important questions concerning possible therapeutic efficacy of SMT.

Legal actions have commenced against chiropractors treating patients presenting with neck and low back pain (with or without radiculopathy) with claims that SMT caused the HNP. These cases are always complex, with very grey areas amidst the patient’s treatment history and evolution of the ultimate result. Most of the time there are no pre-treatment MRI or CT images available, making it impossible to determine exactly when the HNP occurred. Further, many of these cases include a patient with a lengthy history of off and on neck or back +/- radicular pain. Such a history is consistent with the gradual evolution of the HNP and radiculopathy, further muddying the waters of causation. It is not to say that SMT may not be helpful with certain cases of HNP, however it is important for the clinician to be aware of the unpredictable nature of this ailment. Even when SMT is delivered with the greatest of care, there is the possibility that the patient’s condition could be exacerbated. Therefore, one must ask one’s self what the potential ‘downside’ may be in such a condition. It is very likely that in many of these cases the HNP was already present or in process due to the biology of disc degeneration. However, the reader must reconcile how a treatment thought by some to potentially cause a HNP could at the same time effectively treat the same condition.

It is important to learn if there were any particular, unique patient characteristics shared by the responders in both trials reported by Peterson et al. that may set them apart from others (if there was any particular therapeutic benefit)? It should be emphasized that treatment performed on a patient with a known HNP with well-defined parameters is a different thing from the usual clinical setting where such information is rarely available; therefore, the clinician ought to exercise good judgment extrapolating the results of this study to the clinic. On the other hand, when the clinician encounters a patient with neck and or low back pain with or without radiculopathy, what is one to do? The studies by Peterson et al. suggest that SMT may be an effective treatment for patients suffering from known and quantified disc herniation. It would be interesting to obtain post-treatment data concerning objective evidence for changes in the herniated disc (MRI) or neurological status of the patients post treatment such as EMG. Current guidelines maintain that an acutely herniated disc with progressive neurological compromise is an absolute contraindication to SMT treatment and the over-riding concern of ‘first, do no harm’ must be paramount. The evolution of radiculopathy or neurological embarrassment usually occurs gradually over days, weeks or even months. Therefore, until we understand these pathologies better, perhaps the best approach with these patients should begin with a thorough, meticulous history and examination and patient education. If the patient presents within the developmental phase of a HNP that may progress to radiculopathy (or even myelopathy), conservative treatments such as traction, soft tissue therapy and perhaps acupuncture will pose the least potential for harm, but at the same time provide the clinician with valuable feedback over the course of a few clinic visits. Also, education about the potential for the condition to change over time will fully inform the patient with respect to potential important changes in their symptoms. The HNP may, left to its own devices, progress towards overt spinal cord compromise (in the cervical or lumbar spine) due simply to natural history or trivial trauma.

SMT is arguably the most formidable treatment option available to the chiropractor; thoughtful, reasonable and informed consideration ought to dictate its use. It may be that SMT is an effective and safe therapy for some cases of HNP as detailed within the Peterson et al. studies and there is a need for much for research in this area. However, it is imperative that the clinician be aware that the natural history of some patients suffering from a HNP is to develop frank neurological embarrassment simply due to natural history. The chiropractor needs to manage these cases very carefully for the benefit of all since neither the patient nor the clinician wants to be on the wrong side of Mother Nature or the legal system.

Study Methods:

Inclusion Criteria:
  • Subjects were 18-65 years of age.
  • No contraindications to cervical SMT.
  • Neck pain and moderate to severe arm pain in a dermatomal pattern, sensory, motor or reflex changes corresponding to the involved nerve root.
  • Orthopedic examination showing at least one of the following: positive upper limb tension tests, positive cervical distraction test, positive Spurling test, or cervical rotation < 60 degrees (2).
  • MRI showing CDH at the corresponding spinal segment.
Exclusion criteria:
  • Presence of contraindication to chiropractic treatment, including: tumor, infection, inflammatory spondylarthropathy, acute fracture, Paget disease, severe osteoporosis
  • Previous spinal surgery
  • History of stroke
  • Signs of cervical spondylotic myelopathy
  • Spinal stenosis
  • Pregnancy
On the first visit, the patients completed questionnaires detailing demographic information, a baseline numeric rating scale (NRS) for pain and the Neck Pain Disability Index (NDI). At 2 weeks, 1 month and 2 months after the initial consultation, a research assistant from the university contacted the patients via phone and the NDI and NRS were repeated. Additionally, the patient’s own (perceived) global impression of change (PGIC) were collected, where the patient rated their condition as much worse, slightly worse, no change, slightly better, better and much better. Only the responses of “much better” and “better” were considered clinically relevant improvement. On the other hand, responses of “slightly worse,” “worse,” and “much worse” were all regarded as worsening of the condition to err on the side of caution. The percentage of patients improved or worsened was then calculated. Additionally, patients with symptoms lasting 4 weeks or less (acute) were compared with patients who had symptoms 4 weeks or longer (subacute/chronic).

A standard treatment procedure of a single, HVLA cervical manipulation with rotation to the opposite side and lateral flexion to the same side of the affected arm was performed. The goal of this procedure was to move the affected segment and produce an audible release (cavitation). The presence or absence of release was not recorded, as it was not achieved in all cases. In the case where an audible release was not achieved, the chiropractor performed the manipulation up to 2 additional times. Treatments were performed 3-5 times/week for the first 2-4 weeks, and then 1-3 times/week thereafter until the patient was asymptomatic.

Study Strengths / Weaknesses:

  • No control group to statistically rule out the possibility of symptom resolution due to natural history.
  • All patients were treated by 1 of 3 DCs in one practice in Zurich Switzerland. This might not reflect other chiropractic practices or other practitioners using SMT.
  • Small sample size.
  • All outcomes were self-reported.
  • Follow ups were performed via telephone, while the baseline data were obtained in written format in person. This could potentially influence the results. However, every effort to avoid potential bias in this case was made, as this information was collected by an independent research assistant unknown to the patient.
  • No baseline data for the PGIC (primary outcome measure) was collected, as data for this variable can only be collected after treatment.
  • Comparison of acute to subacute/chronic cases.
  • Use of 3 separate outcome measure, in spite of the fact that they were all self-reported.
  • Use of SMT as the only reported treatment modality. While this might not be best for the patient from a treatment standpoint, it is reasonable to infer that SMT has the power to create positive changes, unadulterated by other forms of treatment.

Additional References:

  1. Casey E. Natural history of radiculopathy. Phys Med Rehabil Clin N Am 2011; 22: 1-5.
  2. Wainner RS, Fritz JM, Irrgang JJ, et al. Reliability and diagnostic accuracy of the clinical examination and patient self-report measures for cervical radiculopathy. Spine 2003; 28: 52-62.