# Next-Generation Flap Monitoring: Systematic Review and Meta-Analysis of Hyperspectral Imaging

## TL;DR

Hyperspectral imaging can detect early signs of tissue failure in surgical flaps, potentially improving patient outcomes by identifying problems before they become visible.

## Contribution

This study provides a systematic review and meta-analysis showing hyperspectral imaging's high sensitivity and specificity in detecting flap complications.

## Key findings

- HSI detected perfusion deficits up to 4.8 hours before clinical signs.
- HSI parameters like THI and NIR-PI can distinguish venous congestion from arterial occlusion.
- HSI showed median sensitivity of 93% and specificity of 96% for detecting compromised flaps.

## Abstract

Early detection of perfusion deficits is crucial for optimal flap outcomes. Hyperspectral imaging (HSI) offers a non-invasive method to assess tissue perfusion, potentially detecting complications earlier than Doppler ultrasound or near-infrared spectroscopy. This systematic review and meta-analysis evaluate the efficacy and diagnostic accuracy of HSI in monitoring flap viability, particularly in detecting ischemia and necrosis. A systematic search of PubMed, ScienceDirect, and Cochrane Library was conducted following PRISMA 2020 guidelines. Studies on HSI's role in flap viability were critically appraised using the Critical Appraisal Skills Programme checklist. A random-effects model was applied for the meta-analysis. Nine studies were included, six focusing on flap complications. HSI demonstrated a median sensitivity of 93% (63–100%) and a median specificity of 96% (81–100%) for detecting compromised flaps, outperforming clinical assessments in some cases. Significant differences were observed between viable and necrotic tissues in four key HSI parameters: Oxygen saturation, tissue hemoglobin index (THI), tissue water index, and near-infrared perfusion index (NIR-PI). THI and NIR-PI effectively differentiated venous congestion from arterial occlusion. However, heterogeneity across the studies indicated a need for standardized protocols. Notably, HSI detected perfusion deficits up to 4.8 hours before clinical signs. HSI shows promise for postoperative flap monitoring, enabling earlier detection of ischemia and necrosis. Future research should focus on standardized imaging protocols, real-time analysis, and larger multicenter trials to confirm HSI's clinical utility and cost-effectiveness.