Transcutaneous Electrical Nerve Stimulation

Transcutaneous electrical nerve stimulation (TENS) is a modality frequently seen within the physical therapy clinic, particularly in the outpatient setting. Clinically, it has been traditionally seen as a way to stimulate the sensory nerves (Prentice, 2011). The thought behind its pain relieving mechanism being that the mind will be subsequently tricked into paying attention to the electrical stimulus rather than the painful stimulus of the affected area (Prentice, 2011). The theory is deemed the gate control theory, and by way of maximally stimulating the sensory nerves, the painful afferent impulses being sent to the spinal cord level will be perceived as less or even not at all (Prentice, 2011).  TENS can also be modified to work via the descending mechanisms or endogenous opiate mechanisms of pain control (Prentice, 2011).

            Low back pain is a common ailment seen within the physical therapy clinic, and as such TENS is often used to treat the condition. Numerous studies have addressed the use of TENS for the treatment of low back pain. Both supporting and refuting evidence has come from these studies. First we will take a look at a few of the current research surrounding TENS as a successful modality in the treatment of low back pain.

            In a study by Melzack, Vetere and Finch, the researchers wanted to address the effectiveness of two common treatments for low back pain: transcutaneous electrical nerve stimulation versus gentle massage over the affected area. The thought behind comparing the two treatments being that both methods provide stimulation to the area, so one sensory input should prove greater than the other. This was a double-blind, randomized study design, in which 41 patients participated. The McGill Pain Questionnaire was used to assess pain levels both before and after treatment. Additionally, the researchers assessed return to function and the affect of the modalities via a straight leg raises and ROM in the low back (specifically flexion). It was found that TENS significantly reduced pain relative to gentle massage(Melzack, Vetere, & Finch, 1983).

Additionally, straight leg raises were improved but no increase in ROM was seen with either modality. This suggests that healing was not stimulated but perhaps the use of TENS to decrease pain allows patients to complete tasks they were previously capable of but unable to do due to pain. Within the group receiving TENS, 85% showed improved pain scores, while only 38% showed improved pain within the gentle massage group. The researchers conclude that TENS is a superior method to pain treatment for low back patients.  One problem seen within this study is that one may question the “massage” employed within the treatment. The researchers applied 4 suction cups that administered specific pressure changes to the area. One could see this as more of a placebo to TENS rather than massage. Either way, TENS would be deemed better than massage or a placebo with the outcomes aforementioned (Melzack et al., 1983).

Another study supports the use of TENS in patients with nonspecific chronic low pain back for controlling pain intensity. Chronic low back pain was described as a duration of greater than three months. One hundred fifty patients were included in a single-blind randomized control trial and divided into three groups (50-50-50) for each TENS, Interferential Current (IFC), and controls.  Significant reductions in pain intensity were found in both the TENS and IFC groups such that 84% of the TENS group and 75% of the IFC group were able to stop using NSAIDs and analgesic drugs after treatment sessions compared with 34% of the control group (Facci, Nowotny, Tormem, & Trevisani 2011). However, most patients in each group were not using any drugs, so more investigation could be performed to solidify these results.

What was more of interest regarding the treatment of pain for subjects was the implied cumulative effect of pain relief over the treatment sessions. Patients were given ten treatment sessions over two weeks. Using a visual analog scale (VAS), patients were evaluated for pain both before and after each treatment session.  In both the TENS and IFC groups, patients had significant reduction in mean pain intensity at the beginning and end of each session and from over the course of treatments. In the IFC group, subjects had the greatest duration of pain relief after session nine and in the TENS group after session ten. It would be worth investigating what the maximal pain relief duration could be for the TENS group beyond session ten, however, only ten sessions were given in this study. The findings here imply that patients should see immediate reductions in pain intensity after each session as well as a cumulative effect of pain relief with more sessions. It is unknown the optimal number of sessions for maximal pain relief while utilizing TENS in treating chronic low back pain (Facci et al., 2011).

A study by Cheing and Hui-Chan examined if a single sixty minute treatment of TENS could modify chronic (clinical) LBP, acute (experimental) pain, and the flexion reflex, an objective pain measurement tool, versus a placebo. Multiple studies can be found that either refute or confirm the thought that placebo treatment is just as effective in modifying pain as TENS and other modalities. This study sought to compare the pain modification in experimental versus placebo group in just one sixty minute session of TENS.  Thirty subjects between the ages of 18 and 50 with chronic low back pain for more than 6 months and experiencing pain daily were included in the trial. Two visual analog scales were use for the subject to report their pain: the VAS (LBP) was used to indentify intensity of LBP and the VAS (FR) was used to record the electrical pain during the FR recording. Also, the flexion response was recorded electromyographically after elicitation by an electrical stimulus to the sole of the foot.

The results showed a decrease in pain to 63.1% using the VAS (LBP) value in the chronic LBP group, and there was no difference in the placebo group. This decrease in pain also remained for the next hour. There were no differences seen between group in the VAS (FR) and flexion response after treatment. These differences were also not seen in the acute experimental pain group. Therefore the researchers conclude that a single sixty minute treatment is indeed beneficial for reducing pain in patients with chronic low back pain as compared to placebo. They believe that this reduction in pain is not seen in patients with acute pain because different nociceptive pathways are used in modifying chronic versus acute pain (Cheing & Hui-Chan, 1999). 

From the above studies, we see that in some instances, TENS can be beneficial for patients with low back pain.  However, there is also current evidence that suggests otherwise. We will now review the studies that did not support the use of TENS for chronic low back pain.  

An evidenced based review by Dubinsky and Miyasaki shows that TENS is ineffective overall in the treatment of chronic low back pain. Two Class I studies were analyzed. In one scenario, TENS was compared to a TENS-sham group, and no benefit was found for TENS using a visual analog scales.  The TENS-sham group was given an apparent “treatment”, however no electrical current was delivered (Dubinsky & Miyasaki, 2010). This particular study was looking for a 20% significant improvement in pain, but this threshold was not reached.  Twenty percent is a liberal definition of significance in pain relief; some studies require 25% or even 50% to be considered significant. The authors of this review did not identify the specific percentage of relief attained (if any) in this scenario.  In the second study, TENS and TENS-sham were administered for patients with multiple sclerosis and chronic low back pain. There were no significant differences in pain relief. Thus, the authors concluded from both Class I studies that TENS is not a good treatment choice for chronic low-back pain (Dubinsky & Miyasaki, 2010). The authors did not indicate how many subjects were included in each study; that would have been helpful to determine the reliability of these studies.

In a different study by Chou and Huffman, researchers again wanted to explore the common modalities used within the physical therapy practice to treat low back pain. The researchers began by identifying common treatments including exercise, massage, diathermy, superficial head, transcutaneous electrical nerve stimulation and more. The authors then performed a review of literature surrounding the topic and included studies through 2006 (Melzack, Vetere & Finch’s study previously discussed in our article was included in this study).  They chose to only include randomized trials, which included outcomes for the treatment of low back pain. In summary, the study found that cognitive-behavioral therapy, exercise and spinal manipulation were moderately effective in chronic low back pain. In contrast, acute low back pain was only found to significantly improve via superficial heat and possibly spinal manipulation. Overall, through the review of 16 clinical trials specifically addressing low back pain and TENS, there is insufficient evidence to suggest TENS is superior to “sham TENS” or any other intervention. The systematic review also suggests that minor skin irritation occurs in 1/3 of patients receiving TENS (Chou & Huffman, 2007).

A study by Deyo et al, sought to determine if TENS was more effective than a general stretching and exercise program with sham TENS, and if the addition of TENS to an exercise program adds any benefit. One hundred forty- five patients were randomly assigned to 1 of 4 groups: TENs alone, TENS plus exercise, sham TENs alone, or sham TENS with exercise. The patients were assessed at follow ups on functional performance, pain (using VAS scales as well as self- rating intensity and frequency), and physical performance. The results found no additive benefit of TENS.  At a one month follow up there was no significant effect of TENS on functional performance, pain, or physical performance, and there was no additional effect seen when adding TENS to exercise. Also, there was no significant difference between the TENS and sham TENS treatments. The most significant result is that at the one month follow up, the exercise alone group showed decreased VAS scores, frequency of pain, and improved functional performance. However, it is important to note that at the two month follow up, if the subject in the exercise group had stopped doing their exercises, the before seen improvement were no longer there. Thus it is important to stress to patients that they need to continue their exercises if they want continued improvements in pain reduction (Deyo et al., 1990).

In analyzing the evidence both in support of and refuting the use of TENS for chronic low back pain; it is our opinion that TENS may have some pain relieving benefits for a certain patient group. The decrease in pain seems to be immediate, but not long too long in duration.  None of the studies reviewed claimed that the pain was nonexistent, but rather that the pain was decreased.  Whether you choose to use TENS or an alternative analgesic modality, we believe it is important to refer to current evidence and utilize best judgment for each patient situation.  

References

 
Cheing, G. & Hui-Chan, C. (1998). Transcutaneous electrical nerve stimulation: nonparallel           antinociceptive effects on chronic clinical pain and acute experimental pain. Archives of               Physical Medicine and Rehabilitation, 80(3), 305-312.

Chou, R., & Huffman, L. H. (2007). Nonpharmacologic Therapies for Acute and Chronic Low Back Pain: A Review of the Evidence for an American Pain Society/American College of Physicians Clinical Practice Guideline. Ann Intern Med, 147(7), 492-504. Retrieved from http://www.annals.org/cgi/content/abstract/147/7/492.

Deyo, R., Walsh, NE, Martin, DC, Schoenfeld, LS, & Ramamurthy, S. (1990). A Controlled Trial of Transcutaneous Electrical Nerve Stimulation (TENS) and Exercise for Chronic Low Back Pain. The New England Journal Of Medicine, 322: 1627–34.

Dubinsky, Richard M. & Miyasaki, Janis. (2010). Assessment: Efficacy of transcutaneous electric nerve stimulation in the treatment of pain in neurologic disorders (an evidence-based review): Report of the Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology. Neurology 2010; 74;173.  doi: 10.1212/WNL.0b013e3181c918fc.

Facci, Ligia M., Nowotny, Jean P., Tormem, Fabio, & Trevisani, Virginia F.M. (2011). Effects of transcutaneous electrical nerve stimulation (TENS) and interferential currents (IFC) in patients with nonspecific chronic low back pain: randomized clinical trial. Sao Paulo Med Journal 129(4), 206-16.

Melzack, R., Vetere, P., & Finch, L. (1983). Transcutaneous electrical nerve stimulation for low back pain. A comparison of TENS and massage for pain and range of motion. Physical therapy, 63(4), 489-93. American Physical Therapy Association. Retrieved from http://ptjournal.apta.org/content/63/4/489.abstract

Prentice, William E. (2011). Therapeutic Modalities in Rehabilitation. (4^th ed.). China: McGraw-Hill Companies, Inc.  

Manual Lymphatic Drainage

The clinical syndrome that we chose was lymphedema following breast cancer.  Breast cancer is the most common cancer in women and will typically affect one out of eight women over the course of their lifetime (Breast Cancer, 2010). If the breast cancer is diagnosed and treatment is started quickly there is a very positive prognosis for these patients.  However, there are side effects of the treatment and one of the side effects is lymphedema.   One technique that a physical therapist can use is called manual lymphedema drainage.  This is a technique that has shown positive effects when combined with other modalities.  The technique involves using your hands to pump the arm and push the lymph into uninvolved lymph nodes. The purpose of this blog entry is to review six articles, three pro manual lymph drainage and three against it.   

Articles Supporting MLD

The first article we found was taken from the British Medical Journal and was published January 2010 issue (Torres Lacomba et al., 2010).  This study was a randomized, single blinded, clinical trial. Their objective was to study the effects that early physical therapy would have on women, who had surgical treatment for breast cancer, and the likelihood of secondary lymphedema developing. According to the authors, seventy one percent of women develop secondary lymphedema after surgery for breast cancer, which could be attributed to multiple factors.  The factors include lymph node removal, obesity, wound infection, lack of range of motion, and drainage.  The study involved patients at a hospital over at three-year span.   Women were included if they had unilateral surgery and axillary lymph node dissection.  The patients were randomly assigned into two groups, a control group and an intervention group.  The interventions group received manual lymph drainage from an experienced physiotherapist, performed exercises for the muscle group affected by the surgery, and were educated on the lymphatic system.  The control group received the same educational information that the interventions group received, but they did not have the other two interventions.  The statistical comparisons were binary outcome analysis to view the likelihood of lymphedema developing and continuous outcome analysis to view how the circumference changed, as well as the difference in arm circumference of two adjacent locations. 

The first article found that physiotherapy, manual lymph drainage, and patient education had a significant effect.  The interventions group developed secondary lymphedema in seven percent, while twenty-five percent of the control group developed lymphedema.  The authors stated that oedemas are caused by an imbalance of filtration and reabsorption.  The theory of the manual lymph drainage is that it helps to move lymph out of the affected tissue and improves the reabsorption.  The author’s of the study hypothesized that the manual lymph drainage post surgery had the possibility to increase positive outcomes.  According to the authors’ their limitations included the time frame of their follow up and that they chose one criteria for diagnosing lymphedema.  However, the authors’ believed that their intervention had a positive effect on the women who have unilateral surgery with axillary node dissection.  They believed their intervention helped to prevent secondary lymphedema, which in turn improves the quality of patient life. 

The second article analyzed 138 women of whom 55% had a combination of four types of treatments: manual lymph drainage (addressed in our video), compression, arm exercises, and deep breathing (also addressed in our video). 32% of the women received manual lymph drainage alone and 13% had very mild lymphedema which was treated by the patient themselves with instructions from a therapist.

The results showed that there was a 55.7% improvement in the women that had all four therapies concurrently and 41.2% improvement in the women that had manual lymph drainage alone.  Due to the embarrassing, and possibly debilitating, nature of a severely swollen limb due to lymphedema, this article provides important evidence in support of the manual lymphatic drainage intervention.

The final article supporting MLD consisted of two groups: the first group received MLD followed by simple lymphatic drainage (SLD), and SLD followed by MLD.  Thirty-one subjects that had unilateral lymphedema of greater than 10% for at least 3 months one year after breast cancer treatment participated in this study. The first group received 3 weeks of MLD (15 treatments), followed by 6 weeks of nothing, and then 3 weeks of SLD.  The second group had 3 weeks of SLD, followed by 6 weeks of nothing, and then 3 weeks of MLD (15 treatments).  This study showed that MLD in the early phases of lymphedema produced a statistically significant reduction in excess limb edema (9.65%), compared to SLD, which had a non-significant reduction in limb volume (3.85%).

Articles Refuting MLD

The first article that was against manual lymph drainage (MLD) was a randomized, single blind, control study (Devoogdt et al., 2011).  This study objective was to view how patients with breast cancer and axillary node dissection would respond to an intervention of MLD, exercise, and education.  The patients were selected over at two and half year time period based on their surgery and lymph node dissection.  From this they narrowed their patients down to one hundred sixty patients who agreed.  The patients were randomly selected for the interventions or control group.  The difference between the two groups was that the interventions group would receive MLD for 20 weeks beginning with the first week after the drainage tube was removed.  The MLD treatment began with the neck and axillary nodes, followed by the back and breast tissue, and finally the arm and hand.  This was done using a proximal to distal drainage technique.  Four different therapists performed this method of MLD, these for therapists also instructed the patients through exercise and education.

            The primary results of this study were that patients in the interventions group had almost the same likelihood of developing lymphedema after surgery.  According to the study, twenty four percent of patients in the interventions group developed lymphedema, as opposed to only nineteen percent in the control group.  The secondary outcomes were that each group had similar changes in arm volume.  According to the authors, after the six months of treatment the interventions group had no statistically significant changes.  This led the authors to conclude that MLD does not affect the prevention of lymphedema over a short time period.  This study did provide limitations and strengths.  The limitations of the study were half of the therapists performing the treatments were inexperienced (trained before the study) while the other half had more experience.  The strengths of the study were pre and post surgery measurements, stratification of patients, and randomized grouping. 

            The second article that was against MLD was a prospective, randomized control study that compared the use of MLD with compression versus only compression (McNeely et al., 2004).  The purpose was to look at how effective the combination of MLD and compression would be at decreasing volume of lymphedema. The patients were females with unilateral breast cancer and axillary node dissection.  As another exclusionary criteria the patients were required to be diagnosed with lymphedema.  The patients were randomly placed into either the control group (receiving only compression bandage) or the intervention group (compression and MLD).  The patients in each group received 4 weeks of treatment.  For the group receiving MLD the Vodder method was used.  The compression bandaging was layered and short stretch bandages were applied in a figure eight pattern. 

            The primary outcome of this study was that there was not a significant difference between the control group and the intervention group.  This was determined by the difference in the unaffected arm compared to the affected arm.  The authors’ point out that their study is in agreement with previous studies regarding compression and MLD.  However, the authors’ do mention that the patients who had mild lymphedema had better results from the MLD and the compression.  The authors’ hypothesize that because they have mild lymphedema there is still a functioning lymphatic system, which allows the lymph to be moved effectively.  They also hypothesize that the compression affects the filtration rate from artery to tissue and because the pressure is changed there is an increase in venous return.  Based on these two ideas they believe that compression is more effective in severe lymphedema due to lymphatic system damage.  The limitations for this study included the time period, upper extremity range of motion was not measured, and they did not assess pain, function, or quality of life. 

            The final article aimed to find out if MLD, added to standard therapy, improved the outcome for patients with stage 1 or 2 lymphedema after breast cancer treatment. Andersen et al. said that the most important reduction of edema happens in the first two weeks.  Forty-two patients at least 4 months post breast cancer treatment who had one or more symptoms of unilateral lymphedema, a difference in limb volume of at least 200 ml, and/or a difference of circumference of at least 2 cm participated in this study.  They were randomly assigned to receive standard therapy or standard therapy plus MLD.  Standard therapy included a custom made compression sleeve, education, and exercises.  The experimental group received standard therapy plus MLD 8 times in 2 weeks and was instructed on simple lymphatic drainage for home.  The results concluded that both groups had significant reduction in lymphedema, especially in the first month, and then continued to slightly decline in the next 11 months.  The standard therapy group saw a 60% reduction of edema after 3 months, compared to 48% in the MLD group.  Both groups reported a significant reduction of limb volume, discomfort, and an increase in joint mobility.

            Collectively, these articles suggest that compression, especially in the early stages of lymphedema, is the most important aspect of treatment. However, including MLD in treatment may help clear edema in some patients.  Because MLD is a massage technique there also could be psychological benefits for the patients that were not quantified in any of the studies we viewed.  In conclusion, the articles were somewhat inconclusive, but showed that MLD does have positive benefits when combined with other treatments.  

References 

Andersen, L., Højris, I., Erlandsen, M., & Andersen, J. (2000). Treatment of breast-cancer-related lymphedema with or without manual lymphatic drainage--a randomized study. Acta oncologica (Stockholm, Sweden), 39(3), 399-405. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/20218087 

Breast Cancer." PubMed - Health. 28 Dec. 2010. Web. 03 Feb. 2012. <http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001911/>.

Devoogdt, N., Christiaens, M.-R., Geraerts, I., Truijen, S., Smeets, a., Leunen, K., Neven, P., et al. (2011). Effect of manual lymph drainage in addition to guidelines and exercise therapy on arm lymphoedema related to breast cancer: randomised controlled trial. Bmj, 343(sep01 1), d5326-d5326. doi:10.1136/bmj.d5326

McNeely, M. L., Magee, D. J., Lees, A. W., Bagnall, K. M., Haykowsky, M., & Hanson, J. (2004). The addition of manual lymph drainage to compression therapy for breast cancer related lymphedema: a randomized controlled trial. Breast cancer research and treatment, 86(2), 95-106. doi:10.1023/B:BREA.0000032978.67677.9f

Rashmi Koul, M.D., Tarek Dufan, M.D., Catherine Russell, B.P.T., Wanda Guenther, R.M.T.,Zoan Nugent, Ph.D., Xuyan Sun, M.Sc., Andrew L. Cooke, F.R.C.P.C. "Efficacy of complete decongestive therapy and manual lymphatic drainage on treatment-related lymphedema in breast cancer." International Journal of Radiation Oncology*Biology*Physics (2007): 841-846.

Torres Lacomba, M., Yuste Sanchez, M. J., Zapico Goni, A., Prieto Merino, D., Mayoral del Moral, O., Cerezo Tellez, E., & Minayo Mogollon, E. (2010). Effectiveness of early physiotherapy to prevent lymphoedema after surgery for breast cancer: randomised, single blinded, clinical trial. BMJ, 340(jan12 1), b5396-b5396. doi:10.1136/bmj.b5396

Williams, a F., Vadgama, a, Franks, P. J., & Mortimer, P. S. (2002). A randomized controlled crossover study of manual lymphatic drainage therapy in women with breast cancer-related lymphoedema. European journal of cancer care, 11(4), 254-61. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/12492462