Transcutaneous Electrical Nerve Stimulation (TENS) for Postoperative Pain Relief

Original Editor - Aminat Abolade

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Introduction[edit | edit source]


Traditional management of postoperative pain with the use of opiates has resulted in unwanted side effects such as respiratory depression, nausea and vomiting, hypotension and bradycardia, pruritus and inhibition of bowel movements.  Investigations on effective management of postoperative pain with minimal side effects has led to the use of Transcutaneous Electrical Nerve Stimulation (TENS) due to its success in pain control.

The effects of extensive use of Transcutaneous Electrical Nerve Stimulation (TENS) to control postoperative pain has been quite controversial and this can be attributable to the varying intensity of postoperative pain and the type of surgical operation performed.[1]

How Transcutaneous Electrical Nerve Stimulation is applied [edit | edit source]

Description[edit | edit source]

Transcutaneous Electrical Nerve Stimulation (TENS) is a non-invasive, non -pharmacologic method of pain relief through electrical stimulation. The use of TENS postoperatively has showed a reduction in the use of analgesics in patients and a reduction in occurrence of postoperative complications such as respiratory depression. Although, reports have showed that some surgical procedures are too painful for TENS to have a significant effect on pain such as in severe postoperative pain after posterior thoracotomy.

Application of TENS as an auxiliary therapeutic method in management of acute and chronic pain of various abdominal and thoracic surgeries occurred since 1970. Its use was based on the Gate Control Theory of Pain and daily repeated application produces analgesic tolerance at spinal opioid receptors and increases the toleration threshold of pain. In addition, TENS results in the release of endorphins, serotonin, analgesic hormones and reduction of cytokine levels and increases blood flow to the muscle tissue. Recent studies have showed that use of TENS in patients resulted in significant pain reduction during respiratory manoeuvres and higher maximal expiratory pressure[2], improvement in pulmonary function, low blood cytokine levels and narcotic consumption[3] and improvement in cognitive functions in patients undergoing spinal surgery[4].

Studies in Postoperative Rehabilitation[edit | edit source]

Effects of Transcutaneous Electrical Nerve Stimulation (TENS) on postoperative pain in patients who underwent different types of thoracic surgical procedures: posterolateral thoracotomy, muscle-sparing thoracotomy, costotomy, sternotomy, and video-assisted thoracoscopy.[5]
Assessment of the effectiveness of TENS was carried out based on two factors: the time from the beginning of treatment to the request for further analgesia and the total medication intake during the first 12 hours after operation. Three treatment groups: TENS, Placebo TENS and Control were used and each patient group was randomly subdivided into them.
TENS treatment was not effective in the posterolateral thoracotomy group while its use as an adjunct to analgesics was effective in the muscle-sparing thoracotomy, costotomy, and sternotomy groups. When TENS was applied without analgesics being used, it was very effective in patients having video-assisted thoracoscopy.
Conclusions from this study showed that TENS is not effective for severe pain and should be applied only when postoperative pain is mild to moderate after thoracic surgical procedures.
Effects of Transcutaneous Electrical Nerve Stimulation (TENS) on acute postoperative pain intensity and mobility after Hip Fracture[6]
Twenty-four hours after surgery, the standard rehabilitation care began which included five-daily 30 minutes physical therapy treatments. Intensity of pain at rest, at night and during ambulation were evaluated using the Numeric Rating Scale, Functional Ambulation Classification instrument, time to complete five sit-to-stand tests and two-minute walk test. Wilcoxon score rank tests was used to analyse the data.
Remarkable loss of pain during walking and higher level of mobility in the active TENS group compared to the sham TENS group but no further effects were noted on pain intensity at rest and at night and on five times sit-to-stand performance.
Inclusion of TENS to the standard care of elderly patients in the early days following Gamma nail surgical fixation of extracapsular hip fracture is recommended for pain management while walking and functional gait recovery. Further investigations on the effects of TENS on long-term functional outcomes should be done.
Effects of Transcutaneous Electrical Nerve stimulation (TENS) on persistent postoperative pain in rehabilitation of a patient after a multilevel spinal fusion for spinal stenosis[7] TENS was used for up to 8 hours a day in combination with a progressive walking exercise programme from pool to land. Progression was determined from shuttle walk test results.
Reduction in pain and improved walking distance.
Further investigation is needed to confirm the validity of this physiotherapy approach used.
Effects of Transcutaneous Electrical Nerve stimulation (TENS) on postoperative pain relief following inguinal herniorrhaphy[8]
Use of TENS in addition to postoperative analgesia twice daily for 3 days. Data for the active and inactive groups were compared using the Mann-Whitney U test and the Wilcoxon matched pairs signed ranks test.
An infected wound and a basal pulmonary collapse occurred in patients with inactive TENS machine. There was no significant difference between the groups with active or inactive TENS machines for either pain score, peak flow or pethidine requirement. Pain diminished significantly with time after operation, Peak expiratory flow decreased markedly after operation and then rose gradually.
Use of TENS did not reduce postoperative pain but TENS had considerable patient appeal and many patients believed that it was effective.

Implications for use in physiotherapy[edit | edit source]

A lot of investigations have been carried out on the clinical efficacy of TENS for acute and chronic pain management including knee osteoarthritis, rheumatoid arthritis, low back pain, neck pain, post-amputation pain, post-stroke pain, spinal cord injury, diabetic peripheral neuropathy, chronic and recurrent headache, neuropathic pain, and cancer pain. However, there was an extensive variation in the frequency of use and this could be attributable to a lack of knowledge of the modality, and neurophysiological rationale underpinning it, or perhaps a lack of confidence with results and often reviewers are unable to make definitive judgement about clinical efficacy because of inadequate Randomised Controlled Trial (RCT) design, poor reporting and concerns about trial fidelity and TENS technique.[9] Consequently, the use of TENS as an adjunct to analgesic medication in multi-modal management of acute post-surgical pain should be considered.

Resources[edit | edit source]

References[edit | edit source]

  1. Cuschieri RJ, Morran CG, McArdle CS. Transcutaneous electrical stimulation for postoperative pain. Annals of the Royal College of Surgeons of England. 1985 Mar;67(2):127.
  2. Galli TT, Chiavegato LD, Liebano RE. Effects of TENS in living kidney donors submitted to open nephrectomy: A randomized placebo‐controlled trial. European Journal of Pain. 2015 Jan;19(1):67-76.
  3. Fiorelli A, Morgillo F, Milione R, Pace MC, Passavanti MB, Laperuta P, Aurilio C, Santini M. Control of post-thoracotomy pain by transcutaneous electrical nerve stimulation: effect on serum cytokine levels, visual analogue scale, pulmonary function and medication. European Journal of Cardio-Thoracic Surgery. 2012 Apr 1;41(4):861-8.
  4. Unterrainer AF, Friedrich C, Krenn MH, Piotrowski WP, Golaszewski SM, Hitzl W. Postoperative and preincisional electrical nerve stimulation TENS reduce postoperative opioid requirement after major spinal surgery. Journal of Neurosurgical Anesthesiology. 2010 Jan 1;22(1):1-5.
  5. Benedetti F, Amanzio M, Casadio C, Cavallo A, Cianci R, Giobbe R, Mancuso M, Ruffini E, Maggi G. Control of postoperative pain by transcutaneous electrical nerve stimulation after thoracic operations. The Annals of thoracic surgery. 1997 Mar 1;63(3):773-6.
  6. Elboim-Gabyzon M, Najjar SA, Shtarker H. Effects of transcutaneous electrical nerve stimulation (TENS) on acute postoperative pain intensity and mobility after hip fracture: A double-blinded, randomized trial. Clinical interventions in aging. 2019;14:1841.
  7. Pons T, Shipton EA. Multilevel lumbar fusion and postoperative physiotherapy rehabilitation in a patient with persistent pain. Physiotherapy theory and practice. 2011 Apr 1;27(3):238-45.
  8. Gilbert JM, Gledhill T, Law N, George C. Controlled trial of transcutaneous electrical nerve stimulation (TENS) for postoperative pain relief following inguinal herniorrhaphy. British journal of surgery. 1986 Sep;73(9):749-51.
  9. Dafny, N. (2014). Pain modulation and mechanisms. In: Neuroscience online. Houston, TX: UTHealth.