Introduction

Intraoperative adverse events (IAE) during surgery can lead to increased mortality,

morbidity, and prolonged hospital stays. However, they are often underreported due to a

lack of standardized classification systems, particularly in major gynaecological surgery. To address this gap, West and colleagues from the QLD Centyre for Gynaecological Cancer developed a new Classification system of intraoperative Adverse Surgical Events (CiASE) that is based on severity and impact on patient recovery.

Methods

Expert gynaecological surgeons from 3 countries participated in developing and validating the CiASE. A workshop was conducted to create a grading system, followed by testing and refinement. Case vignettes were generated from real surgical cases for validation. Surgeons applied CiASE to these vignettes, and inter-rater reliability was assessed. Statistical analysis included calculation of accuracy, sensitivity, specificity, and Krippendorff's Alpha coefficient.

Results

Twenty-five surgeons participated in the validation process. The cohort demonstrated high accuracy in grading IAEs, with 95.2% agreement overall. The system showed good sensitivity and specificity across all grades. Inter-rater reliability was almost perfect (α=0.95), indicating strong agreement among surgeons.

Meaning

CiASE provides a standardized method for classifying intraoperative adverse events in

gynaecological surgery, considering both severity and impact on patient outcomes. It

addresses the underreporting of iAEs. Future research will focus on evaluating clinical

outcomes.

How to apply CiASE

The CiASE only applies to AEs recognised intraoperatively. An AE diagnosed postoperatively that would have logically occurred intraoperatively (but was not recognised) is not regarded as an intraoperative complication and the CiASE will not be applied. The intraoperative AE is assigned intraoperatively but its severity can be changed up to 6 weeks post operatively.

Grade 0 – The absence of an intraoperative AE

- Examples:

o Routine procedure as planned

o Conversion from MIS to laparotomy in the absence of an AE such as laparotomy for

specimen retrieval or adhesions unable to be managed laparoscopically, irrespective

of extended LOS.

o Serosal tear (when mucosa of viscus is not breached)

Grade 1 - Minimal: Intraoperative surgical AE with no or minimal impact on post operative

course or patient outcome (does not prolong LOS).

- Examples:

o Enterotomy (requires breach of mucosa) managed by oversew or bowel resection.

o Cone bx and intraoperative opening of POD

o Blood loss requiring transfusion without prolonging LOS

o Splenic tear without significant consequence

o Uterine perforation without other adverse event

Grade 2 – Moderate: Intraoperative surgical AE impacting on planned postoperative course

or outcome for less than 6 weeks.

- Examples:

o Any intraoperative surgical AE requiring conversion from MIS to laparotomy (e.g.,

bleeding or viscus injury). Note: Conversion from MIS to open without a surgical AE

does not meet criteria for inclusion

o Any intraoperative surgical AE associated with prolonged length of stay and/or

necessitating ICU admission (e.g., CO2 embolus)

o Blood loss requiring transfusion prolonging LOS

o Nerve injury requiring medication and or physiotherapy (self-limiting) < 6 weeks

o Urological injury requiring repair and or stenting with planned delayed cystogram

and or delayed IDC/stent removal

o Intraoperative rupture of adnexa or uterus – requiring adjuvant treatment that

would have otherwise not been required

Grade 3 - Severe: Intraoperative surgical AE, requiring subsequent unplanned readmission

and/or return to operating theatres and/or intervention radiology OR continued or

expected disability as a consequence of treatment beyond 6 weeks from discharge from

hospital

- Examples:

o Intraoperative AE requiring diversion of bowel (stoma)

o Nerve injury (long-term) requiring rehab > 6 weeks

o Any AE requiring associated treatment for longer than 6 weeks

o Splenic injury requiring splenectomy and associated long-term medical treatments

o Uterine perforation requiring adjuvant treatment as a consequence of the injury

(and would not have needed adjuvant treatment in the absence of the event)

Grade 4 – Death: Intraoperative or peri-operatively of any cause