This prospective observational study aims to evaluate the feasibility and clinical utility of near-infrared spectroscopy (NIRS) monitoring applied to paraspinal muscles as a surrogate marker of spinal cord perfusion in patients undergoing major noncardiac surgery.

Spinal cord ischemia represents a rare but devastating complication, often difficult to detect in real time. NIRS provides a non-invasive, continuous monitoring of regional tissue oxygen saturation (rSO₂), potentially reflecting microcirculatory changes in paraspinal tissues and indirectly spinal cord perfusion.

The study will enroll adult patients undergoing major surgery requiring advanced hemodynamic monitoring. NIRS sensors will be placed over paraspinal regions, and rSO₂ values will be continuously recorded throughout the perioperative period. Hemodynamic parameters, including arterial pressure, cardiac output, and other relevant clinical variables, will be simultaneously collected.

The primary objective is to assess changes in paraspinal rSO₂ during perioperative management and their relationship with systemic hemodynamic variables. Secondary objectives include the evaluation of the association between rSO₂ variations and postoperative neurological outcomes, as well as the feasibility and reliability of this monitoring technique in routine clinical practice.

This study may provide preliminary evidence supporting the use of NIRS as a bedside, non-invasive tool for early detection of impaired spinal cord perfusion and for guiding hemodynamic optimization strategies.

pinal cord ischemia is a rare but severe complication associated with major surgical procedures, particularly in patients undergoing complex hemodynamic management. Early detection of impaired spinal cord perfusion remains challenging due to the lack of reliable, continuous, and non-invasive monitoring tools. Current monitoring strategies are indirect and often fail to provide timely information on regional perfusion changes.

Near-infrared spectroscopy (NIRS) is a non-invasive technique that measures regional tissue oxygen saturation (rSO₂) by analyzing the absorption of infrared light by oxygenated and deoxygenated hemoglobin. When applied to paraspinal muscles, NIRS may reflect local microcirculatory changes and potentially serve as a surrogate marker of spinal cord perfusion.

This is a single-center, prospective observational study designed to investigate the feasibility and clinical applicability of paraspinal NIRS monitoring in adult patients undergoing major noncardiac surgery requiring advanced hemodynamic monitoring. Patients will be monitored intraoperatively and during the early postoperative period using NIRS sensors placed bilaterally over the paraspinal regions.

Continuous rSO₂ measurements will be collected and integrated with routinely monitored hemodynamic variables, including arterial blood pressure, heart rate, and, when available, advanced parameters such as cardiac output and dynamic indices of fluid responsiveness. Data will be recorded at predefined time points and during relevant clinical events, such as induction of anesthesia, surgical phases, hemodynamic instability, and postoperative recovery.

The study aims to explore the physiological relationship between paraspinal rSO₂ and systemic hemodynamic changes, as well as to assess the feasibility, signal stability, and reproducibility of NIRS measurements in the perioperative setting. Particular attention will be given to identifying patterns of rSO₂ variation associated with hemodynamic fluctuations.

Data will be prospectively collected using standardized case report forms (CRFs). Data quality will be ensured through predefined data entry procedures, consistency checks, and periodic review of collected variables. All data will be anonymized prior to analysis.

A descriptive statistical approach will be used to summarize baseline characteristics and perioperative variables. Exploratory analyses will be conducted to evaluate the association between rSO₂ trends and hemodynamic parameters. Where appropriate, correlation analyses and regression models may be applied to investigate potential predictors of rSO₂ variation.

Given the exploratory nature of the study, no formal sample size calculation is required; however, enrollment is planned to ensure an adequate representation of the target population and to allow meaningful exploratory analysis.

This study is expected to provide preliminary evidence on the role of paraspinal NIRS monitoring as a non-invasive bedside tool for assessing tissue oxygenation and potentially guiding perioperative hemodynamic management strategies.

Inclusion Criteria:

Adult patients aged 18 years or older Patients scheduled for elective thoracic or thoracoabdominal aortic repair, including open, endovascular (TEVAR/FEVAR), or hybrid procedures Patients undergoing intraoperative paraspinal near-infrared spectroscopy (NIRS) monitoring Written informed consent obtained before enrollment

Exclusion Criteria:

Age under 18 years Emergency surgical procedures Pregnancy Pre-existing paraplegia or severe neurological impairment Skin lesions or conditions preventing correct placement of NIRS sensors Refusal or inability to provide informed consent

Adult patients undergoing elective thoracic and thoracoabdominal aortic repair procedures, including open, endovascular (TEVAR/FEVAR), and hybrid interventions, at Monaldi Hospital, A.O.R.N. Ospedali dei Colli, Naples, Italy. Participants will be recruited consecutively from the vascular and cardiovascular surgical units where intraoperative spinal cord monitoring is routinely performed.