Development of an endonasal Raman spectroscopy probe for pituitary adenoma surgery

Surgical resection is a primary therapeutic option for parasellar tumors, including pituitary adenomas at the skull base. Endoscopic transsphenoidal surgery enables tumor removal through the nasal cavities employing endoscopic visualization and specialized instruments. Accurate identification and delineation of the tumor is challenging yet crucial, as the objective is to achieve gross total resection (GTR) while minimizing damage to the surrounding normal structures. Current intraoperative diagnostic modalities, such as MRI, CT, ultrasound probes, and fluorescence imaging have been clinically implemented; however, these techniques are not universally accessible, often require significant time and cost, or cannot deliver reliable real-time feedback. This study presents the development of a fiber-optic Raman spectroscopy probe specifically adapted for endonasal surgical applications to meet clinical needs. The instrument was designed to be integrated with current transsphenoidal surgery workflows, enabling real-time <i>in situ</i> interrogation of parasellar anatomical structures, including the pituitary gland. Before clinical deployment, the probe was evaluated in an <i>ex vivo</i> animal study designed to assess its ability to distinguish parasellar intracranial structures with <i>in situ</i> Raman spectroscopy measurements and machine learning-based classification. Preliminary results from a clinical study deployed at the Centre hospitalier de l'Université de Montréal (CHUM), including measurements acquired on 11 patients during tumor resections, revealed distinct Raman signatures and fluorescence variations across tissue and tumor types. Early SVM-based classification achieved encouraging accuracy rates, highlighting the potential of this approach, although further validation is necessary. Key challenges, such as interference from endoscopic light sources and blood contamination, were identified and addressed. This research sets the foundation for the clinical deployment of Raman spectroscopy as an intraoperative realtime decision support system for safer and more effective pituitary adenoma surgeries.