American Surgical Association

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Topic: H. Quality of Life Outcomes Analysis (clinical and/or financial)

Negative Appendectomy and Imaging Accuracy in the Washington State Surgical Care and Outcomes Assessment Program (SCOAP)

David R Flum1, Joseph Cuschieri1, Michael Florence2, Gregory J Jurkovich1, Scott R Steele3, Richard Thirlby4
1University of Washington, Seattle, WA;2Swedish Medical Center, Seattle, WA;3Madigan Army Medical Center, Tacoma, WA;4Virginia Mason Medical Center, Seattle, WA

Our objective was to determine rates of negative appendectomy (NA), a measure of surgical quality, across 16 statewide hospitals and the relationship of NA and computed tomography/ultrasound (CT/US), which have been found to influence NA.
The Surgical Care and Outcomes Assessment Program (SCOAP) gathers prospective, chart-abstracted data for consecutive operative procedures at Washington State hospitals. Through SCOAP, rates of NA and CT/US concordance with pathology reports were calculated for 2006-2007.
2421 patients underwent urgent appendectomy (67% laparoscopic). 84% (women-88%, men-81%) had imaging (CT-89%, US-11%). The rate of imaging across hospitals ranged from 55-97%. There was 90.1% agreement between imaging and pathology report findings (91.4%-CT and 82.2%-US). The rates of NA and perforation were 6% (women-8%, men-4%) and 17%, respectively. CT/US was performed in 73% of NAs but the interpretation was concordant in only 14.3% of cases. The range of NA between hospitals was considerable (0 - 11%) and higher rates of NA were associated with lower rates of CT/US concordance (Table).
Most patients (84%) with appendicitis in Washington State undergo preoperative CT/US with higher rates of NA when no imaging is obtained. Variation in NA between hospitals is more linked to CT/US accuracy than differential utilization of preoperative testing. This suggests that rates of NA and CT/US accuracy rather than use of imaging alone should be considered measures of quality.
Imaging TypeCTUSNo Imaging
Negative Appendectomy5.2%6.8%10.1%

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