Approval for the study was granted by the Clinical Research Ethics Committee (decision no: 2012-KAEK-15/1539, dated:25.10.2017). The study included 60 patients of the American Society of Anesthesiologists (ASA), scored 1-2-3, who underwent elective laparoscopic cholecystectomy. The patients were separated into two groups of QLB and TAP, using the block randomization method. Informed consent was obtained from all the patients.
The patients included in the study did not have opioid use (Reviewer )
Each groups (group 1 and 2) includes 30 patients. (Reviewer )
At one hour preoperatively, the patients were admitted to the block room. ECG, non-invasive blood pressure (NIBP), and SpO2 monitorization were applied and an IV access route was opened. Premedication of 0.3 mg/kg midazolam was administered by IV to the patients preoperatively. The block sealed envelope was given by the research coordinator to the anesthetist, who was to apply the block and who was blinded to the study. QLB or TAP block was applied according to the randomized groups.
TAP blocks were performed in the supine position and the QLB block was performed in the lateral decubitus position but the doctor who evaluated the data did not know what method (Reviewer 1)
The volunteer code, age, gender, BMI, and ASA score of the patients were recorded. The duration of the block, number of additional fentanyl doses intraoperatively and at postoperative 0-1-2-4-6-12-24 hours, total PCA morphine consumption, number of requests for morphine, VAS values, shoulder pain, heartrate, systolic and diastolic blood pressure, SpO2, sedation score (Ramsey scale), itching, nausea and vomiting, respiratory depression, and other complications were also recorded.
TAP block was applied to patients in Group 1. With the patient in a supine position, the area where the procedure was to be applied was cleaned with surgical solution. A linear USG probe was placed transversely over the iliac crest. The probe was then directed cranially until the three abdominal muscles—namely, the external oblique muscle, internal oblique muscle, and transversus abdominis muscle—could be clearly identified. Using the in-plane technique, a 21-gauge 100 mm needle was advanced from medial to lateral. An injection of 20 ml 0.25% bupivacaine, which is used routinely in regional blocks, was made between the fascia of the internal oblique muscle and the transversus abdominis muscle (lateral TAP block). The same procedure was repeated on the other side.
QLB was applied to the patients in Group 2. With the patient in the lateral decubitus position, the area where the procedure was to be applied was cleaned with surgical solution. A linear USG probe was placed transversely over the iliac crest. There was no complications about using USG. (Reviewer )
The probe was then directed cranially until the three abdominal muscles—namely, the external oblique muscle, internal oblique muscle, and transversus abdominis muscle—could be clearly identified. The USG probe was then directed to the posterior of the muscle until the QL muscle could be clearly seen after the internal oblique muscle. The QL muscle, the psoas major muscle in the anterior, and the transverse process were visualized. Using the in-plane technique, a 21-gauge 100 mm needle was advanced from the posterolateral to the anteromedial. Passing the fascia on the anterior surface of the QL muscle, an injection of 20 ml 0.25% bupivacaine, which is used routinely in regional blocks, was made between the QL muscle and the psoas major muscle (anterior QLB/transmuscular QLB). The same procedure was repeated on the other side.
The duration of the procedure for each block was recorded, and at 30 mins. after the procedure was completed, the patient was transferred to the operating room. General anesthesia (2–3 mg/kg propofol, 1 cg/kg fentanyl, 0.6 mg/kg rocuronium) was applied with the standard procedure.
From the restricted randomization methods, the permuted block randomization method was applied for the grouping of the patients. Each patient was assigned a number from 1–60. With a block size of six, with three cases and three controls in each block, the patients were separated into 20 blocks by calculating three permutations of the six.
The study was designed as a double-blind study. Accordingly, the patients were unaware of which block was to be applied (patient blind). A statistics specialist who was not involved in the research applied the patient randomization using the permuted block randomization method and wrote which block was to be applied inside envelopes numbered from 1 to 60. The sealed envelopes were given to a designated researcher immediately before the procedure (researcher blind). This researcher applied the block that was written in the envelope without stating which one it was. After completion of the block procedure, another researcher who was unaware of which block had been applied recorded the intraoperative and postoperative monitorization values and made the evaluations (evaluating assistant researcher blind).
The dose of fentanly was applied when the patient’s arterial blood pressure %20 increased. (Reviewer)
As a result of the power analysis applied for the Independent Samples t-test using the PASS 11 software (power and sample size, version 11, for Windows), the total sample size required was determined to be at least 60 subjects. The power of the test in this situation was approximately 80.22%.
The data obtained in the study were analyzed using IBM SPSS version 24.0 software (IBM Corporation, Armonk, NY, USA). Descriptive statistics were stated as mean ± standard deviation (SD), minimum, maximum, median, number (n), and percentage (%) values. Conformity of continuous variables to normal distribution was evaluated first with the Kolmogorov–Smirnov Goodness of Fit test. In the comparison between two groups, the t-test was applied to variables with normal distribution and the Mann–Whitney U test to those not showing normal distribution. In the intragroup comparisons, as the data did not conform to normal distribution in the Kolmogorov–Smirnov Goodness of Fit test, analyses of repeated measurements after the block application were made with the Friedman test. The Wilcoxon signed-rank test was applied to determine which group the difference originated from.