Thoracic Paravertebral Block in Daytime Laparoscopic Partial Adrenalectomy

1. Study purpose

To investigate the impact of thoracic paravertebral block for postoperative analgesia and quality of recovery following daytime laparoscopic partial adrenalectomy. 2. Study design

2.1. Type of the study

The research is a single-center, double-blind, randomized-controlled clinical trial.

2.2 Sample size calculation

The estimated sample size was calculated using SPSS Statistics, version 26.0 ((IBM Corp), and this was based on our preliminary study, in which the scores of the QoR-15 scale (points, mean ± standard deviation) of the control group and the TPVB group at 24 hours postoperatively were 116.2±6.7 and 124.3±8.8, respectively. The test level α was set to 0.05, the test power 1-β was set to 0.90. The sample size was determined to be 28 patients in each group. Considering a dropout rate of approximately 20%, 35 individuals were included in each arm of this trial.

2.3 Randomization and blinding

Patients were randomly assigned in a 1:1 ratio into 2 groups, the control group or the TPVB group via centrally computer-generated group randomization. Immediately after the surgery, a sealed opaque envelope containing the patient group assignment was opened by an experienced anesthesiologist in charge. TPVB was performed by the same anesthesiologist for the patients in the TPVB group, while the patien in the control group did not receive nerve blockade.

Participants in the control and TPVB groups were kept blinded to their group assignment. This study involved researchers who conducted the postoperative follow-up and evaluation (blinded) and researchers who administered the treatment (unblinded). The unblinded researchers who administered the interventions were not involved in the evaluation of the postoperative outcomes.

2.4 Intervention protocol

After surgery and before extubation, the patient was positioned in an upper lateral position on the affected side. For patients in the TPVB group, an ultrasound high-frequency linear array probe was used to perform a mid-sagittal scan at the T8-9 spinous process interspace on the affected side. The probe was moved to visualize the T8-9 transverse process and pleura. Using the out-of-plane needling technique, the needle was inserted between the costotransverse ligament and the pleura in the paravertebral space adjacent to the thoracic vertebra. After confirmation of no blood or cerebrospinal fluid return, 30 mL of 0.5% ropivacaine hydrochloride was injected. Under ultrasound guidance, the spread of the medication and downdraft of the pleura could be observed. The patients in the control group did not undergo the nerve block procedure. 3. Adverse events

Including postoperative nausea and vomiting, as well as postoperative agitation and nerve block- related complications, such as bleeding, hematoma, pneumothorax, or nerve injury 4. Quality control

All research data, both in paper and electronic formats, will be kept for at least 5 years. If readers have any questions after the article\'s publication, they may contact the corresponding author for access to the original data. Patient information will remain anonymous, including name, ID number and telephone number. All data related to enrolled patients collected during the study period of this project will be archived and safeguarded, and all study members and study sponsors are asked to keep subject information confidential. The study protocol will be reviewed and revised by statistical experts. Investigators will adhere to pre-defined standard operating procedures, encompassing patient screening, follow-up standardization, result assessment, and data management. The Ethics Committee of Shanxi Bethune Hospital will review the trial every six months. 5. Statistical analysis

Statistical analysis was performed using SPSS Statistics, version 26.0. Normally distributed continuous variables were presented as mean (SD) values, and intergroup comparisons used independent-sample t-test. Nonnormally distributed variables were presented as median (IQR) values, and intergroup comparisons were determined using the Mann-Whitney test. Categorical variables were expressed as frequencies and percentages, and these were compared using either the χ2 test or the Fisher exact test. A P\<0.05 was considered to be statistically significant.

• pain scores at rest and during coughing [Time frame: 1, 6, 12, 24, and 48 hours after surgery]
• Opioid consumption [Time frame: 48 hours postoperatively]
• Rate of remedial analgesia [Time frame: 48 hours postoperatively]
• Postoperative gastrointestinal function outcomes [Time frame: 12, 24, and 48 hours after suegery]
• Times to first flatus and defecation [Time frame: 48 hours postoperatively]