Impact of TENS on Postoperative Pain and Quality of Life After Inguinal Hernia Repair

Study Overview
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Brief Summary
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Lichtenstein herniorrhaphy still remains one of the most often performed inguinal hernia repair techniques. It is frequently associated with acute postoperative and chronic pain. Due to insufficient effect of non-steroidal anti-inflammatory drugs, they are often overdosed. However opioids have many side effects. Interventional treatment, such as transversus abdominis plain (TAP) block requires an additional intervention and has relatively short effect, also could not be applied in outpatient conditions. The hypoalgesic effect of transcutaneous electric nerve stimulation (TENS) is well known for many years, but effectiveness during postoperative period is still controversial and maybe therefore didn't come to daily practice. However it could be a promising part of multi-modal pain treatment for hernia patients. This study analyse the hypoalgesic effect of TENS and its impact on hernia specific quality of life (QoL) after Lichtenstein hernia repair. Aim#1 To determine whether use of TENS is effective for acute postoperative pain relief. Aim#2 To determine whether use of TENS have impact on hernia specific QoL in early and late postoperative period. Aim#3 To identify factors associated with effectiveness/ineffectiveness of TENS procedures. Aim#4 To determine whether a psychological condition (depression, anxiety and pain catastrophisation) is somehow associated with TENS effectiveness.

Official Title
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Impact of Transcutaneous Electric Nerve Stimulation (TENS) on Postoperative Pain and Quality of Life (QoL) After Inguinal Hernia Repair

Conditions
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Inguinal Hernia, Postoperative Pain, Quality of Life, Transcutaneous Electric Nerve Stimulation

Intervention / Treatment
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* Device: Transcutaneous electric nerve stimulation


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Elective Lichtenstein repair for primary hernia Male gender No TENS procedures in the past American Society of Anesthesiologists physical status I or II No cognitive, speaking, hearing or visual disturbances No movement disorders Exclusion Criteria: Non Lithuanian speaker Known allergy to a patch glue Chronic use of non-steroidal anti inflammatory drugs or opioids Neuropathic diseases General contraindication for TENS procedures (such as skin disorders in site of electrodes application or pacemaker) Not able to complete the questionnaires

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 75 Years

Sexes Eligible for Study
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Male

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Active TENS group<br>Conventional transcutaneous electric nerve stimulation | Device: Transcutaneous electric nerve stimulation<br>* Conventional transcutaneous electric nerve stimulation<br>* Other names: TENS;|
| Placebo Comparator: Placebo TENS group<br>0 amperes transcutaneous electric nerve stimulation | Device: Transcutaneous electric nerve stimulation<br>* Conventional transcutaneous electric nerve stimulation<br>* Other names: TENS;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in pain level as assessed by the VAS. | Pain is assessed using a 100 mm handheld slide rule-type visual analogue scale (VAS) with values from 0 to 100 (0 = no pain, 100 = extreme pain) during lying, waking and getting out of bed. Total scores are averaged. | 10 min before and 10 min after each TENS procedure, which occur 24, 26, 48 and 50 hours after surgery. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in pressure pain threshold. | Pressure pain threshold assessed using digital pressure algometer examination in inguinal region (hernia and contralateral side). Pressure in newtons (N) that evokes minimal sensation of pain is assessed. | 1 hour before surgery (baseline), 10 min before and 10 min after each TENS procedure, which occur 24, 26, 48 and 50 hours after surgery. | 
| Change in pressure pain tolerance. | Pressure pain tolerance assessed using digital pressure algometer examination in inguinal region (hernia and contralateral side). Pressure in newtons (N) that evokes maximal tolerable sensation of pain is assessed. | 1 hour before surgery (baseline), 10 min before and 10 min after each TENS procedure, which occur 24, 26, 48 and 50 hours after surgery. | 
| Change in hernia specific quality of life. | Hernia specific quality of life is assessed using self reported questionnaire Carolina's comfort scale (CCS) application, providing a 0 to 115 score. | 1 hour before surgery (baseline), 2 days, 1 week, 4 weeks and 6 month after surgery. | 
| Change in overall quality of life. | Overall quality of life is assessed using self reported short form (36) health survey questionnaire (SF-36) application.The SF-36 consists of 36 items, that aggregate into 8 parts: Physical Functioning, Role-Physical, Bodily Pain, General Health, Vitality, Social Functioning, Role-Emotional, and Mental Health. Each domain is scored on a value of 0 (poor health) to 100 (best health). | 1 hour before surgery (baseline), 2 days, 1 week, 4 weeks and 6 month after surgery. | 
| Consumption of analgesic drugs. | The total amount of drugs, used for pain relief in hospital. | 2 days postoperative | 
| Depression status influence to TENS effectiveness. | Depression status is assessed using preoperative completed patient health questionnaire- 9 (PHQ-9), providing a 0 to 27 severity score. | 2 days postoperative | 
| Anxiety status influence to TENS effectiveness. | Anxiety status is assessed using preoperative completed generalized anxiety disorder scale -7 (GAD-7), providing a 0 to 21 severity score. | 2 days postoperative | 
| Pain catastrophizing influence to TENS effectiveness. | Pain catastrophizing is assessed using preoperative completed pain catastrophizing scale (PCS) questionnaire, providing a 0 to 52 score. | 2 days postoperative | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Inguinal hernia, Transcutaneous electric nerve stimulation, Postoperative pain, Quality of life, Pain threshold, Algometry