Table 1 Definitions of ClassIntra® classification for intraoperative adverse events [14]

Grade 1

Any deviation from the ideal intraoperative course:

• Without the need for any additional treatment or intervention

• Patient asymptomatic or mild symptoms

Grade 2

Any deviation from the ideal intraoperative course :

• With the need for any additional minor treatment or intervention

• Patient with moderate symptoms, not life- threatening and not leading to permanent disability

Grade 3

Any deviation from the ideal intraoperative course:

• With the need for any additional moderate treatment or intervention

• Patient with severe symptoms, potentially life- threatening and/or potentially leading to permanent disability

Grade 4

Any deviation from the ideal intraoperative course:

• with the need for any additional major treatment or intervention

• patient with life-threatening symptoms and/or leading to permanent disability

Grade 5

Any deviation from the ideal intraoperative course with intraoperative death of the patient