Investigation of rapid evaporative ionisation mass spectrometry (REIMS) in minimally invasive surgery

Abstract

Precision surgery requires technologies that can be used in-situ and can deliver real-time analysis of intra-operative pathology. Currently, surgical strategy is conceived using pre-operative imaging and visual assessment of anatomy intraoperatively, with postoperative histology guiding the necessity for any future intervention. This approach is often subjective, time-consuming, and costly. This project describes the validation of the Harmonic scalpel; an energy device commonly used in minimally invasive surgery, as a new surgical aerosol source for REIMS analysis. The generated surgical aerosol produced during the dissection of different porcine tissues was collected and analysed by REIMS, producing tissue-specific lipid profiles in positive and negative ionisation modes. Comparison with other surgical energy tools, such as monopolar electrosurgery and CO2 laser was made. Classification performance of the Harmonic-REIMS platform was assessed on different porcine tissue models showing 100% accuracy. To further understand how different technical and environmental conditions can impact the metabolic composition of colorectal mucosa tissue and affect REIMS spectra using the Harmonic device, a phantom environment was designed and developed. Real-time measurements of different conditions and spectral information were assessed, showing how REIMS is most likely to be impacted by changes in humidity, temperature, and presence of mucosal contamination, during the in vivo translation of the technology. Using the Harmonic-REIMS platform, a clinically annotated spectral database (n=286) was created ex vivo, including colorectal tissue from 23 patients. The diagnostic accuracy of REIMS in differentiating normal and tumour samples was assessed showing an overall diagnostic accuracy of 94%. Finally, as part of the translation of REIMS technology in minimally invasive surgery, in vivo human feasibility studies were made in laparoscopic and robotic surgery.