Here is the design of a clinical trial:

Official Title: Comparison of Analgesic Efficacy of Local Wound Infiltration Plus Transversus Abdominis Plane Block and Local Wound Infiltration Only After Laparoscopic Colorectal Resection: a Randomized, Double-blind, Non-inferiority Trial

Included conditions:
- Colorectal Disorders

Study Armgroups:
- {'label': 'Wound infiltration plus TAP', 'type': 'EXPERIMENTAL', 'description': 'Wound infiltration placed by surgeon + TAP-LAP placed laparoscopically guided by surgeon', 'interventionNames': ['Procedure: Wound infiltration plus TAP']}
- {'label': 'Wound infiltration', 'type': 'ACTIVE_COMPARATOR', 'description': 'Wound infiltration placed by surgeon', 'interventionNames': ['Procedure: Wound infiltration']}

Interventions:
- {'type': 'PROCEDURE', 'name': 'Wound infiltration plus TAP', 'description': '1. TAP block: At the beginning of the main surgical procedure the surgeon will perform a TAP with ropivacaine infiltration, bilaterally in the anterior axillary line, between the costal margin and iliac crest in the intermuscular plane between the internal oblique and transversus abdominis muscles, the anesthesiologist under ultrasound guidance, the surgeon under laparoscopic guidance (two "pops" technique).\n2. Wound infiltration : Wound infiltration of ropivacaine will be performed by the surgeon before skin incision.', 'armGroupLabels': ['Wound infiltration plus TAP'], 'otherNames': ['ropivacaine']}
- {'type': 'PROCEDURE', 'name': 'Wound infiltration', 'description': 'Wound infiltration of ropivacaine will be performed by the surgeon before skin incision.', 'armGroupLabels': ['Wound infiltration'], 'otherNames': ['ropivacaine']}

Primary Outcomes:
- {'measure': 'Pain numerical rating scale (NRS)', 'description': '1. Pain NRS during rest and cough\n2. NRS scale 0-10: 0, "no pain"; 10, "worst pain imaginable"', 'timeFrame': 'within the first 6 hours after surgery'}

Please estimate the sample size based on the assumption: 
A two-sided sample size calculation with 0.8 power, significance level of 0.05, and an estimated dropout rate of 8%.
Sample size calculation
        The null hypothesis is that WI is inferior to WI plus L-TAP. To test the alternative hypothesis of noninferiority of WI compared with WI plus L-TAP, the sample size is calculated using the mean value of NRS. Considering our results with previously treated patients, the mean (standard deviation [SD]) pain intensity score according to NRS is 2.8 (1.9) for the WI plus TAP block group and 3.1 (1.9) for the WI group. These data have been used for the sample size calculation. The noninferiority limit of NRS 1 has been intended to be the largest difference that is clinically acceptable, so that a difference greater than 1 would matter in practice. A two-sided sample size calculation with 0.8 power and significance level of 0.05 reveals that 100 patients have to be included. With an estimated dropout rate of 8%, a sample size of 108 patients is required with 54 patients in the WI group and 54 patients in the WI plus L-TAP group. Patient recruitment is split between the two centers. Sample size has been calculated using PASSÂ® version 14.0.8 with a noninferiority test for the difference of two means.