Measurement of the optical nerve sheath in prolonged robotic surgery and neurological risk

Abstract

Robotics have transformed surgical practice, the pronounced Trendelenburg position (≥30°) is essential to optimize anatomical exposure, but carries underappreciated neurological risks. By compromising cerebral venous drainage, it can induce an increase in intracranial pressure (ICP), even in patients without neurological history. Often silent during general anesthesia, it can trigger cerebral edema that manifests in the postoperative period, with devastating consequences if not anticipated. Non-invasive ICP monitoring is a strategic tool. Ultrasound of the optic nerve sheath (VNO) emerges as a validated and safe alternative. A VNO diameter ≥5.0 mm is associated with pathological ICP (>20 mmHg), studies suggest that progressive changes, even below this threshold, may reflect significant cerebral venous congestion. Clinical Case: a 68-year-old patient, ASA II, underwent a 12-hour robotic prostatectomy at 37° Trendelenburg, in whom the VNO increased from 3.6 mm to 4.5 mm, without reaching diagnostic values ​​of intracranial hypertension. This guided a preventive strategy: intubated transfer to the intensive care unit and anti-edema measures. He progressed favorably, without alterations in the level of consciousness or neurological deficit, and was discharged without sequelae. Conclusion: the interpretation of VNO allows us to detect brain alterations before the appearance of clinical signs. In prolonged robotic surgeries, subthreshold increases should be considered as early warning signs. Decision-making based on this non-invasive monitoring was key to implementing prophylactic measures that avoided potentially irreversible neurological complications.