Neck Solutions

Inclusion of thoracic spine thrust manipulation into an electro-therapy/thermal program for the management of patients with acute mechanical neck pain

From: Man Ther. 2008 Aug 7; [Epub ahead of print]

Approximately 25% of all outpatient physical therapy visits consist of patients with symptoms involving the neck region. It has been found that nearly half of the individuals with neck pain will experience debilitating symptoms. Over a third of patients with neck pain will develop chronic symptoms lasting more than 6 months, and nearly a third who experience a first time onset of neck pain will continue to report continued healthcare utilization for their symptoms at a 10-year follow-up.

Physical therapists utilize a number of interventions in the management of neck pain including joint manipulation (non-thrust and thrust), exercises, massage, thermo-therapy or electrotherapy (American Physical Therapy Association, 2001). However, robust evidence to support the use of many of these therapeutic strategies for neck pain is lacking. The Philadelphia Panel Clinical Practice Guidelines concluded that many commonly used interventions for patients with neck pain lack sufficient evidence to justify their clinical use. Recently, evidence has begun to emerge for the use of manual procedures directed at the thoracic spine for patients with mechanical neck pain. Cleland et al. found that thoracic thrust manipulation results in immediate improvements in neck pain at rest as measured by the visual analogue scale, compared to patients receiving a placebo manipulation. Further, it has also been found that at short-term follow-up patients receiving thoracic manipulation exhibit superior outcomes to patients receiving non-thrust techniques.

The importance of investigating the effectiveness of thoracic spinal manipulation is necessary considering the fact that the thoracic spine is the region of the spine most often manipulated, despite the fact that more patients complain of neck pain. Further, decreased mobility in the thoracic spine has been shown to be related to the presence of neck pain symptoms, so it is possible that manipulation of the thoracic spine may alter the biomechanics of the cervical region and decrease mechanical stress. Finally, it has previously been identified that either cervical mobilization or manipulation induces an activation of descending inhibitory mechanisms; hence, thoracic spine thrust manipulations may also result in a reduction of neck symptoms.

It should be noted that the aforementioned studies solely investigated the effects of thoracic thrust manipulation (with the exception of one study which used range of motion exercise). More often physical therapists use a multi-modal treatment approach (exercise, manual therapy, electrotherapy, etc.) in the management of neck pain which may include thrust techniques directed at the thoracic spine. To date only one study has investigated the effects of thoracic spine manipulation incorporated into a physical therapy management program. Fernandez-de-las-Peñas et al. reported that patients with whiplash-associated disorders receiving thoracic thrust manipulation as a component of a physical therapy program experienced a greater reduction in symptoms than subjects whose physical therapy did not include manipulation. To date no studies have explicitly investigated the effects of thoracic manipulation when it is added to a program including electrotherapy and thermal agents in patients with mechanical neck pain.

Hence, the purpose of this study was to examine the effects of a seated thoracic distraction manipulation when added to a program including electrotherapy and thermal modalities on neck pain, disability, and cervical mobility.

Forty-five patients, 20 males and 25 females, between 23 and 44 years of age with acute mechanical neck pain referred by their primary care physician to a physical therapy clinic participated in this study. For the purpose of this study mechanical neck pain was defined as generalized neck or shoulder pain with mechanical characteristics (including symptoms provoked by neck postures, neck movement, or palpation of the cervical musculature) of less than 1month in duration. Exclusion criteria included the following: (1) contra-indication to manipulation; (2) history of whiplash or cervical surgery; (3) diagnosis of cervical radiculopathy or myelopathy; (4) diagnosis of fibromyalgia syndrome; (5) having undergone spinal manipulative therapy in the previous 2months; or (6) less than 18 or greater than 45 years of age.

Chiu et al. found that the application of transcutaneous electrical nerve stimulation with a TENS unit combined with other physical approaches was effective for improving neck muscle strength, neck pain and perceived disability. In the present study, the standardized program included the application of superficial thermal therapy and electrotherapy as follows: an infrared lamp, located 50cm distant from the patient’s neck, was applied for 15 min. After superficial thermal therapy, TENS with a frequency of 100Hz and 250ms stimulation was applied for 20 min using two 4×6cm electrodes placed bilaterally to the spinous process of C7 vertebra.

The results of our study demonstrated that patients with acute mechanical neck pain receiving an electrotherapy/thermal program plus thoracic thrust manipulation experienced a significantly greater reduction in pain and disability as well as an increase in cervical mobility compared to a group that received electrotherapy and thermal only. The effect sizes were large for all of the dependent variables assessed in favour of the thoracic spine thrust manipulation group. Additionally, it should be noted that between-group differences for pain achieved by the thoracic spine thrust manipulation group was not only statistically significant but also clinically meaningful as it exceeded the minimum clinically important difference (MCID) on the NPRS, identified as 2 points. Although the MCID for the NPQ has not been reported, within-group improvements were significantly greater for subjects in the experimental group.

The current results further substantiate the findings of previous studies, all of which demonstrated that thoracic thrust manipulation resulted in changes in pain, disability and cervical mobility in different populations of patients with neck pain. While the effect sizes in this study were large, they could have potentially been greater if the inclusion criteria had included a specific subgroup of patients who are likely to exhibit a rapid and dramatic improvement from thoracic manipulation. Cleland et al. recently developed a clinical prediction rule with 6 variables from patients with mechanical neck pain. This study identified 6 predictor variables (symptom duration less than 30 days, no symptoms distal to the shoulder, looking up does not aggravate symptoms, Fear-Avoidance Beliefs Physical Activity subscale score less than 12, decreased upper thoracic spine kyphosis (T3–T5), and cervical extension less than 30 degrees). If 3 of the 6 variables were present, the probability of experiencing a successful outcome improved from 54% to 86%. In the present study, patients with acute (less than 30 days) neck pain were included, so our patients presented with at least 1 of the predictors identified by Cleland et al.

The physiological mechanism associated with the benefits of thrust manipulation is beyond the scope of the present study and remains to be fully elucidated. Further, both biomechanical and neuro-physiological (either segmental or central) mechanisms have been suggested. For instance, the biomechanical link between the cervico-thoracic spine and neck pain described by Norlander et al. may be one reason why thoracic spine manipulation is beneficial for patients with neck pain. It is also possible that spinal manipulative therapy has inherent qualities that can alter the biomechanics of the treated region (thoracic spine), and it is likely that those segments are bio-mechanically related to the cervical region. One mechanism could be that the manipulative procedure may induce a reflex inhibition of pain or reflex muscle relaxation by modifying the discharge of proprioceptive group I and II afferents. It is also plausible that thrust manipulation decreases pain and spasm while increasing mobility through changes in muscle electrical activity; reduced muscle spasm or increased inter-segmental joint play subsequent to a spinal manipulation. Further, mechanical stimulus induced by the manipulative procedure may also alter concentrations of inflammatory mediators, or trigger segmental inhibitory mechanisms. Finally, activation of descending inhibitory pathways may explain the decreased cervical symptoms after the application of a manipulation in another region. Nevertheless, it seems that more than 1 mechanism likely explains the effects of spinal manipulative therapy, and there is insufficient evidence to claim a major role for either peripheral or central mechanisms. Future research is clearly necessary to determine if mechanisms by which manipulation exerts its effects are either mechanical or neuro-physiologic or both.

We found that the inclusion of thoracic manipulation combined with a standard electrotherapy/thermal program results in significantly greater reductions in neck pain and disability as well as increases in neck mobility in the short-term in patients with acute mechanical neck pain. Our findings suggest that when treating young adults with acute mechanical neck pain clinicians should consider the findings of this trial in their decision-making. Future studies are needed to investigate the long-term effects of thoracic spine thrust manipulation in patients with neck pain.