TENS for Pain and Sleep After Hernia Surgery (TENS-HERNIA)

The Effect of Transcutaneous Electrical Nerve Stimulation (TENS) on Postoperative Pain and Sleep After Inguinal Hernia Surgery: A Randomized Controlled Trial

This study evaluates whether Transcutaneous Electrical Nerve Stimulation (TENS) improves postoperative pain and sleep quality in adults undergoing inguinal hernia surgery. After surgery, participants will receive physician-supervised TENS or usual care. Pain intensity and sleep quality will be measured and compared between groups to assess the effectiveness and safety of TENS as a supportive recovery method.

Study Overview

• Status: Not yet recruiting
• Conditions: Postoperative Pain; Inguinal Hernia; Sleep Disturbance
• Intervention / Treatment: Device: Transcutaneous Electrical Nerve Stimulation (TENS); Other: Standard Postoperative Care

Detailed Description

This randomized controlled clinical trial investigates the effects of Transcutaneous Electrical Nerve Stimulation (TENS) on postoperative pain and sleep quality in patients undergoing inguinal hernia repair. Inguinal hernia is one of the most common surgical conditions worldwide, with increasing prevalence in recent years. Although tension-free herniorrhaphy has become the gold standard technique due to its low recurrence rate, rapid recovery, and cost-effectiveness, chronic postoperative inguinal pain (CPIP) remains a significant complication that negatively affects quality of life. CPIP is typically defined as new or altered groin pain persisting for more than three months after surgery, and its pathophysiology is not fully understood. Nerve injury or entrapment of the ilioinguinal, iliohypogastric, or genitofemoral nerves is considered a major contributor.

Postoperative pain management often relies on opioid analgesics, which carry risks of dependence, respiratory depression, and prolonged hospitalization. Therefore, non-pharmacological alternatives are of growing interest. TENS is a minimally invasive neuromodulation technique that modulates pain signals, most commonly explained by the Gate Control Theory, in which stimulation of large myelinated fibers inhibits transmission of pain through smaller nociceptive fibers. Previous studies have suggested potential benefits of TENS in CPIP, but evidence remains limited and inconsistent. Moreover, chronic pain is frequently associated with sleep disturbances, further impairing physical and psychological well-being. TENS may therefore improve both pain and sleep quality in this patient population.

The study will be conducted between October 2025 and October 2026 at the General Surgery Department of SBÜ Adana City Training and Research Hospital. Eligible participants will be adults (≥18 years) undergoing inguinal hernia surgery who are conscious, cooperative, and without contraindications to TENS. Exclusion criteria include cardiac pacemakers or implanted electronic devices, uncontrolled epilepsy or neurological disorders, chronic opioid use prior to surgery, severe psychiatric or cognitive impairment, dermatological conditions at electrode sites, requirement for additional analgesic/regional block during follow-up, or concurrent participation in another clinical trial.

Sample size was determined by power analysis, requiring 40 patients in the intervention group and 40 in the control group (total n=80) to detect a significant difference with α=0.05 and power=0.80. Data collection will include a Personal Information Form, the Visual Analog Scale (VAS) for pain intensity, and the Richards-Campbell Sleep Questionnaire (RCSQ) for sleep quality. VAS is a validated, simple, and widely used tool for assessing subjective pain intensity, while the RCSQ evaluates multiple dimensions of sleep quality using visual analog scales.

The primary hypothesis is that TENS will reduce postoperative pain and improve sleep quality compared with standard care. The null hypothesis states that TENS has no effect on these outcomes. Ethical approval has been obtained, and all procedures will be performed under physician supervision to ensure patient safety.

• Study Type: Interventional
• Enrollment (Estimated): 80
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Kezban Koraş SÖZEN, Associate Professor; Phone Number: +90-0543 805 62 09; Email: kezbankoras@ohu.edu.tr

Study Locations

• Turkey (Türkiye)
  • Adana, Turkey (Türkiye)
    • Adana City Hospital
    • Contact: Kezban Koraş SÖZEN, Associate Professor; Phone Number: +90, 0543 805 62 09; Email: kezbankoras@ohu.edu.tr
    • Contact: Abdurrahman ACAR, RN, MSc; Phone Number: +90, 0541 529 89 30; Email: aacar@ohu.edu.tr

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Adults (≥18 years) undergoing elective inguinal hernia surgery

Ability to provide informed consent

Willingness to comply with study procedures

Exclusion Criteria:

• History of epilepsy, cardiac pacemaker, or other contraindications to TENS

Severe psychiatric or neurological disorders affecting pain or sleep assessment

Allergy or intolerance to electrode materials

Patients requiring emergency surgery

Inability to complete questionnaires (VAS, PSQI)

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Arm 1 (Experimental): TENS Group; Participants in this arm will receive physician-supervised Transcutaneous Electrical Nerve Stimulation (TENS) following inguinal hernia surgery. TENS will be applied to the inguinal region using surface electrodes according to a standardized protocol. The intervention aims to reduce postoperative pain and improve sleep quality compared with standard care.	Device: Transcutaneous Electrical Nerve Stimulation (TENS); Physician-supervised application of TENS to the inguinal region after hernia surgery, following a standardized protocol.
Active Comparator: Arm 2: Standard Care Group; Participants in this arm will receive standard postoperative care following inguinal hernia surgery, without TENS application. Outcomes will be assessed in the same way as the experimental group for comparison.	Other: Standard Postoperative Care; Participants in this arm will receive routine postoperative care following inguinal hernia surgery, without TENS application.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Postoperative Pain Intensity	Pain intensity will be measured using the Visual Analog Scale (VAS) at 6, 12, and 24 hours postoperatively.	First 24 hours after surgery
Change in Pain Intensity (VAS)	Pain intensity will be measured using the Visual Analog Scale (VAS) at 6, 12, and 24 hours postoperatively.	First 24 hours after surgery

Collaborators and Investigators

• Sponsor: Nigde Omer Halisdemir University

Study record dates

Study Major Dates

• Study Start (Estimated): January 10, 2026
• Primary Completion (Estimated): October 1, 2026
• Study Completion (Estimated): October 10, 2026

Study Registration Dates

• First Submitted: December 10, 2025
• First Submitted That Met QC Criteria: December 21, 2025
• First Posted (Actual): January 6, 2026

Study Record Updates

• Last Update Posted (Actual): January 6, 2026
• Last Update Submitted That Met QC Criteria: December 21, 2025
• Last Verified: December 1, 2025

More Information

Terms related to this study

• Keywords: Postoperative Pain; Inguinal hernia; Transcutaneous Electrical Nerve Stimulation (TENS); Sleep Disturbance
• Additional Relevant MeSH Terms: Pain; Neurologic Manifestations; Nervous System Diseases; Mental Disorders; Postoperative Complications; Pathologic Processes; Pathological Conditions, Anatomical; Sleep Wake Disorders; Hernia; Hernia, Abdominal; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Pain, Postoperative; Parasomnias; Hernia, Inguinal; Therapeutics; Physical Therapy Modalities; Rehabilitation; Anesthesia and Analgesia; Electric Stimulation Therapy; Analgesia; Transcutaneous Electric Nerve Stimulation
• Other Study ID Numbers: 22504254-050.04-NOHU; SAT 2025/15-BAGEP (Other Identifier: Niğde Ömer Halisdemir University Scientific Research Projects Coordination Unit)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: Individual participant data will not be shared.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No