Exploring the Impact of Transcutaneous Electrical Acupoint Stimulation Therapy on Postoperative Pain, Quality of Life, and Blood Inflammatory Markers in Lung Cancer Patients After Video Assisted Thoracoscopic Surgery
Phase: NA
Conditions: Pain, Postoperative
Sponsor: Buddhist Tzu Chi General Hospital

STATISTICAL ANALYSIS PLAN 
Effect of Transcutaneous Electrical Nerve Stimulation and 
Acupuncture-related Stimulation 
on Postoperative Pain and Recovery Following 
Video-Assisted Thoracoscopic Surgery 
Randomized Controlled Trial 
ClinicalTrials.gov Identifier: NCT Number Pending 
Version: 3.0 
Date: December 2, 2025 
Principal Investigator: 
Lin, Chun-Ya RN, MSN 
Graduate Student, Department of Nursing, Tzu Chi University 
Affiliated Unit: Department of Surgical Intensive Care, Tzu Chi Hospital 
IRB Approval No.: IRB113-050-B 
Sponsor / Institution: Tzu Chi Hospital and Tzu Chi University 
Document Type: Statistical Analysis Plan 
 
 

1. Study Overview 
This randomized controlled trial investigates the analgesic and physiological effects of 
Transcutaneous Electrical Nerve Stimulation (TENS) and TENS combined with 
acupuncture-related stimulation (TENS+TANS) on postoperative pain management and 
recovery among patients undergoing Video-Assisted Thoracoscopic Surgery (VATS). 
Participants are randomly assigned into three groups: Control (standard care), TENS, and 
TENS+TANS, with repeated assessments at preoperative (T0), immediate postoperative 
(T1), and postoperative day 2(T2). 
2. Objectives and Hypotheses 
Primary Objective: To evaluate whether TENS or TENS+TANS significantly reduces 
postoperative pain intensity compared to standard care following VATS. 
Secondary Objectives: To assess the effects of these interventions on emotional status 
(HADS), inflammatory indices (e.g., NLR, LMR), and postoperative complications. 
Hypotheses: 
H1: TENS and TENS+TANS will result in lower NRS pain scores over time compared to 
Control. 
H2: The TENS+TANS group will demonstrate greater improvements in emotional outcomes 
and recovery parameters. 
3. Study Design and Intervention Groups 
A total of approximately 93 participants will be recruited and randomly allocated to one of 
three groups using a computer-generated randomization table. Interventions will be 
applied postoperatively according to group assignment. Data will be collected at three time 
points (T0, T1, T2) for repeated-measures analysis. 
Groups: 
• Control: Standard postoperative care only. 
• TENS: Conventional TENS applied according to thoracic pain dermatome. 
• TENS+TANS: TENS combined with acupuncture-related electrical stimulation following 
meridian theory. 
4. Outcome Measures 
Primary Outcome: 
• Numeric Rating Scale (NRS) pain intensity scores at rest and during activity. 
Secondary Outcomes: 
• Inflammatory indices: NLR, LMR 

• HADS (Anxiety, Depression) 
• Drainage volume, blood loss, operation type, and tube type 
5. Statistical Methods 
• All analyses will be conducted using IBM SPSS Statistics 25 (Armonk, NY, USA). 
• Descriptive Statistics: Mean ± SD or median (IQR) for continuous variables; frequencies 
and percentages for categorical variables. 
• Baseline Comparison: One-way ANOVA or Kruskal–Wallis test for continuous variables; 
Chi-square or Fisher’s exact test for categorical variables. 
• Primary Analysis: Repeated-measures ANOVA to test for within-subject effects (time), 
between-subject effects (group), and time × group interaction. Greenhouse–Geisser 
correction will be applied if sphericity is violated. Partial eta-squared (η²p) will be reported 
as effect size. 
• Post-hoc Analysis: Bonferroni-adjusted pairwise comparisons for significant main or 
interaction effects; Cohen’s d will quantify between-group effect sizes. 
• Secondary Analysis: Logistic regression to identify predictors of moderate-to-severe pain 
(NRS ≥ 4), including covariates such as age, sex, operation type, and drainage volume. Model 
performance will be assessed using Hosmer–Lemeshow goodness-of-fit and AUC of ROC 
curve. 
• Sensitivity Analysis: Penalized (Firth) logistic regression and bootstrap resampling (1,000 
iterations). 
• Significance Level: Two-tailed p < 0.05. 
6. Sample Size Calculation 
Based on G*Power 3.1 calculations for a repeated-measures ANOVA (3 groups × 3 
measurements), with medium effect size f = 0.25, α = 0.05, and power = 0.80, a total of 84 
participants are required. To account for 10% potential attrition, 93participants will be 
recruited. 
7. Handling of Missing Data 
Missing data will be analyzed for randomness using Little’s MCAR test. If data are missing at 
random, multiple imputation or expectation-maximization methods will be used. Sensitivity 
analyses will compare results before and after imputation. 
8. Software and Significance Level 
All statistical analyses will be performed using IBM SPSS 25 and verified in R 4.3.2 when 
applicable. Statistical significance will be set at p < 0.05 (two-tailed). Effect sizes will follow 
Cohen’s conventions (small d = 0.2, medium = 0.5, large = 0.8). 
9. Amendments and Version Control 
This Statistical Analysis Plan (Version 3.0, dated December 2, 2025) was prepared prior to 
database lock and unblinding. Any amendments will be documented with justification and 
dated accordingly.