Erector spinae plane block and transverse abdominis plane block for postoperative analgesia in robotic assisted radical prostatectomy- A single centre, prospective, double blind, randomised controlled trial

With the rise in the number of robotic prostatectomy cases, the need for adequate pain relief following the surgery has become important. Due to the adverse effects related to opioids, use of opioid sparing multimodal analgesia techniques including myofascial plane blocks can be used for adequate pain relief.

In this study we plan to divide the patients into two groups and use erector spinae plane and transversus abdominis plane block following surgery with local anaesthetics under ultrasound guidance. Patients would be provided with PCA pumps delivering morphine when required in the postoperative period and bolus fentanyl for breakthrough pain.

Categorical data will be expressed as frequencies (percentage) and analysed using the Chi-square or Fisher exact test. Continuous variables will be presented as means +/-SD or median with interquartile range and will be compared with independent t test or Mann-Whitney U test. Statistical analysis will be performed using the Statistical Package for the Social Sciences software. Sample size calculation will be performed with the G* power 3 software.

The patients will be explained about the risks and benefits of the two methods of analgesia during pre-anaesthesia check up and written informed consent will be taken. They will also be informed about Numeric Rating Scale (NRS) and trained how to operate the PCA pump. All patients will be prepared according to ERAS protocol. In both the groups, general anaesthesia will be administered and routine care will be provided.

For ESPB group, patients will be positioned in a lateral decubitus position. Under ultrasound guidance following hydro-dissection 20 ml of 0.2% ropivacaine will be administered on both sides. In the TAPB group, the block will be performed in supine position. 20 ml of 0.2% ropivacaine will be given under ultrasound guidance following hydro-dissection on both sides.

Outcome measures:-

Primary outcome:

• 24 hours intravenous morphine consumption in mg

Secondary outcome:

• Postoperative rescue fentanyl requirements in mcg in the first 24 hours
• NRS at rest on arrival at the ICU (T0); 3 hours (T1); 6 hours (T2); 12 hours (T3); 24 hours (T4)
• Modified Ramsay Sedation score on arrival at the ICU (T0); 3 hours (T1); 6 hours (T2); 12 hours (T3); 24 hours (T4)
• NRS on first ambulation
• NRS on coughing
• Time to enteric resumption
• Time to ambulation
• Time to flatus pass
• Postoperative nausea and vomiting at the above mentioned time points
• Patient satisfaction score
• Length of hospital stay