Final answer:
The principle of nonmaleficence is upheld when the surgeon refuses to operate on the patient because potential benefit is minimal compared to the pain that the patient will endure.
Step-by-step explanation:
The ethical principle upheld in this scenario is the principle of nonmaleficence. Nonmaleficence is the principle that requires healthcare professionals to avoid causing harm to their patients. In this case, the surgeon is refusing to operate on the patient because the potential benefit is minimal compared to the pain that the patient will endure. By refusing to operate, the surgeon is prioritizing the avoidance of harm to the patient.