# A Novel, Low-Cost, Non-laboratory Training Model for Neurosurgical Microdrilling Skills: A Proof-of-Concept Study

## TL;DR

This study introduces a low-cost, lab-free model using walnuts and a nail drill to train neurosurgical microdrilling skills, showing potential for resident training.

## Contribution

The novel model uses affordable materials to simulate microdrilling without a lab or high-speed surgical tools.

## Key findings

- Consultants successfully drilled without perforation on the first attempt, while residents needed two attempts.
- Participants reported a subtle resistance change before reaching the walnut skin, mimicking real surgical feedback.
- The model allows practicing microdrilling on a delicate substrate without infection risk or lab access.

## Abstract

Introduction

Surgical simulation is essential in neurosurgical resident training for dexterity development in a risk-free environment. Microdrilling is a fundamental neurosurgical skill. Practicing this skill usually requires specially equipped facilities with a biological or synthetic material and thus has limited availability. Up-to-date computerized virtualization cannot fully replace the training of hand-eye sensorimotor coordination. The aim of this study is to develop and preliminarily evaluate a low-cost, lab-free proof-of-concept microdrilling model using walnuts, a nail drill, and surgical loupes and to explore performance differences between neurosurgical residents and consultants.

Materials and methods

We used a surgical loupe with LED light and 3.5x magnification, walnuts, and a battery-powered nail drill. Some walnuts were drilled from the flat surface toward the convoluted surface while preserving the outer skin, whereas in others, the skin was drilled away from the kernel to maintain the natural contour of the walnut. Drilling skills were compared between residents and consultants.

Results

When drilling from the flat surface to the convoluted surface, the truncated cone-shaped drill bit was initially used to flatten the irregular parts of the walnut. The acorn-shaped drill bit and the conical drill were then used to further reach the skin and leaving it intact as in the eggshell peeling technique. For drilling of the skin along the kernel’s surface to maintain its contour, the conical bit was used for precision. While drilling the kernel towards the convoluted surface, no perforations were made after the first attempt by consultants and after two attempts by the residents. All participants reported a subtle loss of resistance just before reaching the skin.

Conclusion

Despite its limitations, our model offers an easily reproducible concept that allows the basic principles of microdrilling to be practiced on a delicate substrate without risk of infection and without requiring a surgical high-speed drill or laboratory access, and it could potentially benefit the drilling skills of residents.