The Effect of Preemptive Regional Anesthesia (TAP-block) on Acute and Chronic Pain After Transabdominal Preperitoneal Inguinal Hernia Repair (TAPP)

The Effect of Preemptive Regional Anesthesia (TAP-block) on Acute and Chronic Pain After Transabdominal Preperitoneal Inguinal Hernia Repair (TAPP) - a Randomized Controlled Trial

The study is devoted to the impact of preemptive regional Transversus abdominal plane block on the postoperative acute and chronic pain after elective Transabdominal preperitoneal (TAPP) inguinal hernia repair.

Inguinal hernia repair is one of the most common elective interventions in general surgery. Approximately 20 million inguinal hernia repairs are performed worldwide every year. Laparo-endoscopic techniques provide faster recovery times, lower chronic pain risk and are cost effective compared to open one.

Nevertheless, laparoscopic inguinal hernia repair can result in moderate to severe pain in the early postoperative period, interfering the time of returning to normal activity in a substantial quantity of patients. To reduce pain and to accelerate recovery, local and regional anesthetics has been successfully implemented into the daily routine of abdominal surgeries.

Recent systematic reviews have shown that TAP block can reduce analgetic consumption and acute pain scores after inguinal hernia repair. However, most included studies were conducted on patients with open hernia surgery or total extra peritoneal (TEP) inguinal hernia repair. Some studies showed the benefit of TAP block for early pain control following TAPP. Most of them were retrospective, some conducted with exclusion of obese or comorbid patients, some in mixed groups without separating patients with TAPP and TEP.

Thus, the evidence of TAP block efficiency prior to hernia repair in TAPP technique are of low quality.

Chronic postoperative inguinal pain (CPIP) develops in up to 6% of patients after TAPP. Several studies have found that intense acute postoperative pain is a risk factor for CPIP after IHR. The investigators hypothesize, that preemptive TAP block temporary stops nociception and central sensitization from the surgical site thus reduce acute postoperative pain that theoretically provoke reducing the incidence of CPIP following IHR. Two studies suggest that TAP block may influence the incidence of CPIP after TAPP. Considering the retrospective study design of both and the insufficient sample size further randomized clinical trials are mandatory to estimate this hypothesis.

The aim of our study is to explore the possibilities of reducing acute and chronic pain after TAPP via implementation TAP block.

The sample size was calculated based on the randomized controlled trial data of patients after TEP IHR where postoperative VAS score at 4 h on coughing was 4.7±1.5 in the preemptive local anesthesia group and 6.1±1.9 in the control group. A sample size of 39 patients was required for each subgroup (total=78 patients) with a type I error rate α=0.05 and type II error rate β=0.1.

Inclusion Criteria:

• Patients with unilateral primary inguinal hernia who are scheduled for elective Transabdominal preperitoneal inguinal hernia repair (TAPP)
• Signed Informed consent to participation
• ASA I-III
• BMI ≤35 kg/m2

Non-inclusion Criteria:

• Inguinoscrotal hernia (hernia passing through the entrance to the scrotum)
• Previously diagnosed mental disorders
• Patients receiving psychotropic drugs and drugs affecting adrenal cortex function (estrogens and systemic glucocorticoids)
• Language barrier

Exclusion Criteria:

• Deviations during the operation/anesthesia that required transfer to the intensive care unit or conversion to open surgery
• Refusal to participate