# Screw Stimulation Thresholds for Neuromonitoring in Minimally Invasive Oblique Lateral Lumbar Interbody Fusion (OLLIF): A Correlational Study

## TL;DR

This study explores how stimulation thresholds for neuromonitoring in minimally invasive spinal surgery compare to open surgery, aiming to establish safe standards.

## Contribution

The study identifies correlations in stimulation thresholds between open and minimally invasive spinal surgeries, suggesting potential standards for the latter.

## Key findings

- A discernible correlation exists between stimulation thresholds in open and minimally invasive surgeries.
- No definitive correlation was found between stimulation thresholds and BMI due to small sample size.
- The results suggest a potential standard stimulation threshold for minimally invasive surgeries.

## Abstract

Introduction: This study presents findings from an investigation into the correlation of neuromonitoring techniques in minimally invasive lumbar fusions and their open counterparts regarding acceptable thresholds for screw stimulation. The threshold for acceptable stimulation value for open surgery has been established. The study compared acceptable thresholds for open pedicle screws where there is more connection between the screw and the soft tissue.

Methods: The neuromonitoring data of 17 patients who underwent oblique lateral lumbar interbody fusion (OLLIF) procedures between September 2023 to May 2024 were reviewed. Neuromonitoring was conducted throughout surgeries, recording stimulation thresholds for pedicle screws insulated and uninsulated, to simulate the environment of a screw during open and minimally invasive surgery respectively. Patients' BMI was also collected for potential correlation analysis.

Results: Results indicate a discernible correlation between stimulation thresholds in open and minimally invasive surgeries, but no definitive correlation with BMI due to sample size limitations. Though a significant correlation between the two stimulating styles is apparent, there is a good correlation to suggest what threshold should determine a standard stimulation threshold for minimally invasive surgeries.

Conclusion: The study emphasizes the need for refined neuromonitoring strategies in minimally invasive spinal fusion (MISF) surgeries to ensure patient safety and surgical effectiveness. Further research with larger cohorts is recommended to establish optimized protocols that have a clearly defined amplitude for MISF thresholds.