Robot-assisted surgery (RAS) is one of the most advanced tools in modern medicine. These systems give surgeons extreme precision, allowing procedures to be performed through small incisions that minimize both pain and recovery time. Yet even with this sophisticated technology, operations still depend on a human surgeon, who has to stay intensely focused for hours while making medical decisions. With RAS being increasingly adopted worldwide, understanding what it demands of the surgeon is critical.
Though scientists know surgeons experience varying levels of stress during an operation, little is known about how that stress changes from moment to moment. Most research has relied on simulated surgeries or questionnaires completed after the fact, making it difficult to capture the rapid changes that occur in the operating room during a real procedure. In RAS, stress should be understood not only over time but also as a whole-body response involving the cognitive processing system, musculoskeletal system, and autonomic nervous system. Knowledge of when and how stress manifests physiologically in surgeons could help improve surgical training, how operating rooms are designed, and how well physicians are supported at work.
In a recent study published online in the journal Surgical Endoscopy on June 30, 2026, a research team led by Professor Yoshihiro Shimomura from the Design Research Institute, Chiba University, Japan, including Dr. Kaiqi Wei and Dr. Nanako Nakamura from the Graduate School of Science and Engineering, Chiba University, and Dr. Shinichi Sakamoto from the Graduate School of Medicine, Chiba University, set out to answer this question by monitoring surgeons during live operations. Their paper presents the results of an observational field study in which multiple physiological signals were recorded simultaneously from seven experienced urologists while they performed robot-assisted procedures.
Each surgeon wore lightweight sensors that recorded brain activity via electroencephalography, shoulder and neck muscle activity via surface electromyography, and heart activity via electrocardiography. Rather than interrupting surgeons' mid-operation to ask how stressed they felt, the team used video-stimulated recall. Simply put, after surgery, each surgeon watched a recording of their own console view and marked the moments when they felt their stress level changed, rating it on a scale of 0 to 9. This enabled the researchers to match notable physiological patterns to specific moments of stress without disrupting the procedure.
By statistically analyzing 151 of these stress-rated moments across the seven surgeons, the team found that four physiological signals reliably tracked how stressed surgeons reported feeling: a pattern of brain activity linked to mental arousal increased, muscle tension in the upper shoulder increased, heart rate sped up, and the natural variability between heartbeats decreased. These signals moved together in a way that lined up consistently with how stressed surgeons said they felt, as confirmed through robust statistical analysis.
These results showcase how unobtrusive physiological monitoring can provide useful information for understanding the challenges faced by surgeons. "Combining surgeon-reported stress annotations with multimodal physiological monitoring is feasible in RAS and may provide a basis for identifying high-demand operative moments during postoperative review," explains Prof. Shimomura.
Looking ahead, the researchers also see this approach as a way to better understand the surgical workplace itself, not just surgeons. "Beyond individual case review, surgeon-state measures could serve as an outcome for evaluating the robotic surgery work system, including console ergonomics, communication routines, workload distribution, procedure-specific difficulty, and training stage. This is the most immediate practical application of the present approach," remarks Prof. Shimomura.
Future studies involving more hospitals and additional surgical specialties could help determine how these measurements may support human-centered surgical technology and healthier working environments for healthcare professionals. "Designing environments, equipment, and operational methods based on the results of this line of research will help manage doctors' stress, improve surgical performance, and enhance surgeons' own well-being. In addition, these findings could be applied to real-time stress relief interventions for surgeons, triggering briefing protocols to enhance surgical safety and supporting stress management for beginners in training using double-console systems," concludes Prof. Shimomura.
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Journal reference:
Wei, K., et al. (2026). Multimodal physiological correlates of surgeon stress in live robot-assisted surgery. Surgical Endoscopy. DOI: 10.1007/s00464-026-13054-3. https://link.springer.com/article/10.1007/s00464-026-13054-3