Electrical Stimulation for Reducing Trapezius Muscle Dysfunction in Cancer Patients: Traditional Treatment Protocols Also Work

Abstract

RE: Baldwin ERL, Baldwin TD, Lancaster JS, et al. Neuromuscular electrical stimulation and exercise for reducing trapezius muscle dysfunction in survivors of head and neck cancer: A case-series report. Physiother Can. 2012;64:317–24. http://dx.doi.org/10.3138/ptc.2011-23O Dear Editor, We read Baldwin and colleagues' report1 in the summer 2012 issue of Physiotherapy Canada with great interest. The topic they raise is of particular interest to us, as we recently treated a patient with oral cancer. Following his neck-dissection surgery, the patient developed a neuropathy of the XIth cranial nerve, with paralysis of the trapezius and sternocleidomastoid muscles. The encouraging results obtained by Baldwin and colleagues led us to try electrical stimulation to promote strength gain in the trapezius muscle and to foster recovery. Unfortunately, the advanced technology used by the authors (allowing, for instance, electrical stimulation to be triggered by electromyographic feedback) was not available at our clinic. Although the technology used by Baldwin and colleagues was interesting, we believed that similar effects could be achieved even without such a feedback system. We therefore started a 6-week treatment programme that included electrical stimulation (ES) and therapeutic exercises (ergocycle, active range of motion [AROM], strengthening). The ES component used a Gymna apparatus designed to stimulate denervated muscles (galvanic current, 1 ms pulse width). The patient came to the clinic three times per week for 6 weeks. The treatment sessions always began with a warm-up period consisting of ergocycle pedaling with moderate resistance for 5 minutes. The patient then completed an exercise routine with the assistance of ES. Specifically, the patient was asked to actively flex both shoulders at the onset of ES and to maintain the contraction as long as he felt the electric current in his dorsal (trapezius) area. The electrodes were positioned on the affected right lower trapezius muscle, based on our physical examination,2 during which we observed marked weakness of the inferior portion of the trapezius. We began with 2 sets of 10 repetitions, then gradually progressed to 3 sets of 12 repetitions at the end of week 2. ES duration was initially set at 5 seconds, progressing to 10 seconds (ON:OFF ratio=1:3). As Table 1 shows, the strength of the affected trapezius significantly improved after treatment. This improvement was associated with increased AROM and, presumably, increased shoulder function. The most important change in muscle strength was observed in the lower trapezius, consistent with our electrode placement. Table 1 Active shoulder range of motion (ROM) and shoulder strength before and after treatment* The treatment protocol used significantly improved the strength of the patient's middle and lower trapezius muscle. We cannot exclude the possibility that the treatment also had beneficial effects on the upper portion of the trapezius. However, because we were unable to break the muscle contraction during our evaluation, we cannot fully appreciate its effect on upper trapezius strength. The absence of upper trapezius weakness at initial evaluation surely raises important questions. Given the patient's history and the structure probably affected by the surgery (the spinal accessory nerve), we would have expected weakness in the whole trapezius muscle. We believe that the strength measured during shoulder shrug might in fact be due to compensation by the levator scapulae muscle. Perhaps a more specific evaluation technique (i.e., with slight arm abduction to inhibit the levator scapulae muscle) would have produced a different pattern of results. As mentioned above, the protocol reported here is simple and easy to apply in a standard physiotherapy clinic setting. Unlike Baldwin and colleagues, we used no feedback system to initiate ES of the affected trapezius. We also placed the electrodes on the muscle itself rather than on the spinal accessory nerve, to avoid the negative impact that ES might have on nerve recovery.3,4 In conclusion, our experience suggests that the treatment protocol described in Baldwin and colleagues' research can be modified slightly yet remain effective. Of course, we believe that physiotherapy practice must evolve and take advantage of the technological breakthroughs and new equipment that are emerging in the medical and paramedical field. Nevertheless, those who have access to a more modest array of equipment can still use ES effectively to treat patients with peripheral nerve lesions.