Epidemiology of negative appendectomy in the modern era: a post-hoc analysis of an EAST multicenter study

Author(s):
Briana Britton; Terry Schaid; Eric Campion; Renaldo Williams; Daniel VanDerPloeg; Fredric Pieracci; Barry Platnick; Ernest Moore; Sany Thomas; Magdalene Brooke Sanchez; Alex Morton; D. Yeh, MD

Background:

Historically, negative appendectomy rates as high as 15% were tolerated and even sometimes encouraged. With widespread use of computed tomography (CT) to diagnose appendicitis, negative appendectomy rates have decreased.

Hypothesis:

We sought to describe the epidemiology of negative appendectomy in the modern era.

Methods:

We performed a post hoc analysis of an EAST multicenter study that prospectively enrolled adults with appendicitis. The cohort included only subjects undergoing appendectomy with “normal appendix” reported as the final pathologic diagnosis. Demographics, imaging data, operative findings, and clinical outcomes for index hospitalization, 30-days and 1-year are presented in descriptive format.

Results:

Out of 3597 subjects in the original MUSTANG cohort, 3262 (91%) were treated with appendectomy and 58 (1.7%) had normal appendix on final pathology. The median[IQR] age was 32 [21-43] years, 16 (28%) were male, and median Alvarado score was 6[4-7]. Preoperative imaging consisted of none in 1 (2%), ultrasound (US) only in 2 (3%), CT only in 45 (78%), US and CT in 7 (12%), magnetic resonance imaging (MRI) only in 0 (0%), and US and MRI in 2 (3%). In those receiving pre-operative CT (n=52), the reading was “acute appendicitis” in 36 (69%). Surgeons described the appendix as acutely inflamed in 32 (55%). In 15 (26%) subjects, alternative intra-abdominal pathology was discovered, with most potentially treatable without surgery (Table 1). Clinical outcomes are presented in Table 2. Nine out of 10 of 30-day ED visits and 12 of 15 of 1-year ED visits were in patients without other intra-abdominal pathology.

Conclusions:

In the modern era, the majority of negative appendectomies performed in adults receive preoperative CT imaging which is often misdiagnosed as acute appendicitis. Emergency Department visits are common at 30 days and 1 year after negative appendectomy without other intra-abdominal pathology.