# Fine-needle muscle microbiopsy: a feasible and well-tolerated alternative for skeletal muscle sampling

## TL;DR

A minimally invasive muscle sampling technique using a fine needle is shown to be well-tolerated and as painless as a routine blood draw.

## Contribution

A refined 20-gauge needle microbiopsy protocol is introduced as a feasible and ethical alternative to traditional muscle biopsy methods.

## Key findings

- Mean pain scores for microbiopsy were low and comparable to venipuncture (1.0 vs. 1.4 on VAS).
- Most participants reported minimal or low discomfort (VAS ≤3) from the microbiopsy.
- The technique provides sufficient material for proteomic analysis with reduced invasiveness.

## Abstract

Conventional muscle biopsy techniques, such as the Bergström method, require large tissue samples and skin incisions. Fine-needle muscle microbiopsy offers a minimally invasive alternative, but data on tolerability are lacking. We aimed to present a refined minimally-invasive muscle microbiopsy protocol using a 20-gauge needle with topical anaesthesia and compare perceived pain with routine venipuncture.

Twenty-six healthy adults (50% female) underwent vastus lateralis microbiopsy using a 20-gauge needle (0.9 mm). Pain was assessed immediately after the microbiopsy and a venous blood draw using a 21-gauge needle, with the visual analogue scale (VAS). Procedures were randomized.

Seventy-eight microbiopsies were successfully obtained. Mean pain scores were low for both procedures (microbiopsy: 1.0 ± 0.9; venipuncture: 1.4 ± 1.2) with no significant difference (P = 0.311). Most participants reported minimal or low discomfort (VAS ≤3) from the microbiopsy.

Fine-needle muscle microbiopsy using a 20-gauge needle is well tolerated, with pain comparable to routine venipuncture. This approach substantially reduces invasiveness compared to traditional biopsies while providing adequate material for proteomic analysis. These findings support its ethical and practical application in sensitive populations and longitudinal research.