Effectiveness of Local Infiltration versus Intramuscular Injection of Tramadol Following Inguinal Herniorrhaphy in Adult Patients at Kayunga Regional Referral Hospital

Background : Inguinal hernia repair is one of the most frequently performed operations worldwide, yet optimal postoperative pain control remains a major clinical challenge, especially in resource-limited settings. Tramadol, a dual-acting opioid and monoaminergic analgesic, provides moderate yet well-tolerated analgesia when administered either systemically or locally. Although its local infiltration has shown promising results, direct comparisons with intramuscular (IM) administration for acute postoperative pain management remain limited. Methods : This prospective, randomized, double-blind, controlled study will enroll 88 adult patients undergoing elective, uncomplicated inguinal herniorrhaphy at Kayunga Regional Referral Hospital in Uganda. Participants will be randomly allocated to receive tramadol 2 mg/kg diluted in 10 ml of normal saline either by local wound infiltration (Group A) or intramuscular injection (Group B) at wound closure. Pain intensity will be assessed using the Visual Analog Scale (VAS) at 4, 6, 12, and 24 hours postoperatively. Secondary outcomes will include the duration of pain-free interval, need for rescue analgesia, and time to first rescue dose. Data will be analyzed using SPSS v22, applying the Mann–Whitney U and Poisson regression tests where appropriate. Discussion : The primary outcome of this study is to compare the occurrence of postoperative pain following open herniorrhaphy using the Visual Analog Scale (VAS) at 4, 6, 12, and 24 hours postoperatively. Additionally, the median operative time from the induction of anesthesia to the completion of the surgical procedure and the cost-effectiveness of the two techniques will be evaluated in both groups. Local infiltration of tramadol following herniorrhaphy under spinal anesthesia has the potential to provide significant benefits to patients, most notably by prolonging pain-free periods, which may lead to greater patient satisfaction and reduced healthcare costs. Conclusions : Local Tramadol infiltration offers superior, longer-lasting, and safer analgesia compared to intramuscular administration after inguinal hernia repair. Its simplicity, affordability, and effectiveness make it a valuable postoperative pain management option, particularly in low-resource settings. Incorporating local tramadol infiltration into multimodal analgesic protocols may enhance postoperative recovery and reduce supplementary analgesic requirements. Trial registration: Pan-African Control Trials Registry (N ̊ PACTR 202510801818332). Registered on 20 ^th October 2025