Prone Position, No Worries: Study Finds No Harm to Brain Circulation During Spine Surgery
When it comes to spine surgeries, the prone position—where a patient lies face down—is the standard. This position provides surgeons with optimal access but also raises important questions about its impact on the body, especially the brain. Are there hidden risks to cerebral hemodynamics or intracranial pressure? A recent study published in BMC Anesthesiology set out to answer these questions using advanced, noninvasive monitoring technology.
Understanding the Concerns
During surgery, positioning isn’t just about convenience; it directly affects a patient's physiology. The prone position can increase intraabdominal and intrathoracic pressures, which in turn elevates central venous pressure (CVP). Higher CVP has the potential to impede blood flow from the brain, possibly raising intracranial pressure (ICP) and affecting how well the brain is perfused with blood. For anesthesiologists and surgeons alike, maintaining stable cerebral hemodynamics is crucial for patient safety.
The Study: Methods and Monitoring
To investigate, researchers enrolled 33 adult patients undergoing thoracolumbar or lumbosacral spine surgery. They used transcranial Doppler (TCD) ultrasound—a noninvasive “stethoscope for the brain”—to monitor key parameters such as peak systolic velocity (PSV), mean flow velocity (MFV), pulsatility index (PI), and resistivity index (RI). These measurements offer insights into cerebral blood flow and resistance.
Patients were evaluated at several time points: before anesthesia, after induction, and at multiple intervals up to 60 minutes after being turned prone. Non-invasive intracranial pressure (nICP) was calculated using a mathematical model based on the PI.
What Did the Results Show?
The big headline: No significant changes in cerebral hemodynamics or nICP were observed when patients were moved from a supine (face up) to a prone (face down) position.
While there were statistically significant decreases in heart rate and blood pressure after assuming the prone position, these remained within normal clinical ranges and were not considered meaningful from a patient safety perspective. Importantly, other variables like end-tidal CO₂, airway pressure, and anesthesia depth also remained stable.
A key takeaway is that meticulous perioperative management—ensuring proper fluid resuscitation, oxygenation, and ventilation—likely helped maintain these stable conditions. The study’s relatively young patient population and conservative use of positive end-expiratory pressure (PEEP) may have also contributed.
Should We Rethink Prone Positioning?
This study brings reassurance: with appropriate monitoring and management, prone positioning for spine surgery does not inherently increase risks for adverse cerebral hemodynamic changes in otherwise healthy adults. However, the authors caution that their results may not apply to older or higher-risk patients, as well as surgeries lasting longer than 60 minutes.
Key Takeaways
• Prone positioning during spine surgery did not significantly impact cerebral hemodynamics or noninvasive intracranial pressure.
• Decreases in heart rate and blood pressure were observed but were not clinically significant.
• Careful management of fluids, oxygen, and ventilation is essential for maintaining brain health during surgery.
• These findings apply primarily to otherwise healthy adults undergoing routine spine procedures.
Reference: Taj, Y., Samagh, N., Paliwal, S. U., Ganesh, V., Dey, A., & Aggarwal, V. (2025). Effect of prone position on cerebral hemodynamics and noninvasive intracranial pressure assessed using transcranial Doppler in patients undergoing spine surgeries: a prospective observational study. BMC Anesthesiology, 25, 242. https://doi.org/10.1186/s12871-025-03116-9
