MON-463 - Clinical Impact of Local Anesthesia in Thyroid Fine-Needle Aspiration Biopsy: A Systematic Review and Meta-Analysis

Introduction: Thyroid fine-needle aspiration biopsy (TFNAB) is the standard diagnostic test for thyroid nodules meeting biopsy criteria. Although TFNAB is brief and usually well tolerated, pain during the procedure remains variable and may impact patient comfort and procedure efficiency. The use of local anesthesia has been proposed to reduce pain and improve procedural outcomes. However, its benefits remain uncertain and inconsistently reported across studies.

Objective: We aim to assess whether local anesthesia before TFNAB may improve procedure-related pain, sample adequacy, procedure duration, and patient self-reported satisfaction compared with placebo or no anesthesia.

Method: We systematically searched PubMed, Embase, Cochrane Library, and ClinicalTrials.gov from inception to April 2026 for clinical studies evaluating local anesthesia before TFNAB compared with placebo or no anesthesia. Primary outcomes were pain scores and sample adequacy according to the Bethesda System. Secondary outcomes were procedure duration and patient self-reported satisfaction. Pooled standardized mean differences (SMDs) and risk ratios (RRs) with 95% confidence intervals (CIs) were calculated using random-effects meta-analyses. For self-reported satisfaction, we conducted a qualitative synthesis of clinically relevant outcomes due to the limited number of studies (fewer than three) available for these outcomes. All statistical analyses were performed on R software.

Results: We included seven studies, comprising 1286 patients, of whom 58.55 % underwent local anesthesia for TFNAB. Our study showed that local anesthesia was not associated with a significant overall reduction in pain scores (SMD -0.29, 95% CI -0.74 to 0.16; P=0.21; I2=92%) and sample adequacy (RR 1.09, 95% CI 0.95-1.26; P=0.23; I2=86%). Patient self-reported satisfaction favored anesthesia (satisfied with analgesia: 87.3% vs 46.2%; rated anesthesia necessary: 79.4% vs 5.6%).

Conclusion: Our study showed that routine local anesthesia before TFNAB was not significantly associated with decreased pain scores or improved specimen adequacy compared with placebo or no anesthesia. However, patient self-reported satisfaction between studies favored local anesthesia over placebo or no anesthesia during TFNAB.
Keywords: Thyroid fine-needle aspiration biopsy, thyroid nodule, local anesthesia, pain, specimen adequacy, meta-analysis.

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