Original scientific article
Computed Tomography-Based Clinical Diagnostic Pathway for Acute Appendicitis: Prospective Validation

https://doi.org/10.1016/j.jamcollsurg.2006.08.012Get rights and content

Background

Despite our regular use of CT for suspected appendicitis, a recent study at our institution demonstrated a negative appendectomy (NA) rate similar to our rate 15 years earlier. Based on analysis of this data, a diagnostic pathway was implemented prospectively for adult patients with possible appendicitis.

Study design

Rates of CT, NA, and perforation for nonpregnant patients over 14 years of age undergoing appendectomy between August 2001 and August 2002 (PRE) were compared with prospectively collected pathway data (PATH, August 2004 to August 2005). All PATH patients were evaluated by a surgeon before CT. All females underwent CT. CT was obtained in male patients with low suspicion or pain for longer than 48 hours. After negative CT, patients were discharged from the emergency department or admitted for observation.

Results

There was a substantial decrease in NA rate after implementation of the pathway (4% PATH [8 of 183] versus 16% PRE [31 of 196], p < 0.001), without a change in the rate of perforation (11% PATH [20 of 175] versus 8% PRE [13 of 165], p = 0.28) or frequency of preoperative CT (59% PATH [108 of 183] versus 60% PRE [118 of 196], p = 0.84).

Conclusions

Frequent appendiceal CT alone does not ensure surgical diagnostic accuracy. CT need not be used in all patients to achieve very low NA rates. An evidence-based diagnostic algorithm incorporating early surgical evaluation, objective criteria for preoperative CT, deterrence of early operation after negative CT, and use of CT to facilitate safe discharge led to substantial improvements in the care of our adult population presenting with possible appendicitis.

Section snippets

Retrospective analysis (PRE group)

Data from the most recent year of our previous retrospective review7 were analyzed, consisting of all nonpregnant patients older than 14 years of age who underwent appendectomy or CT for suspected appendicitis at our institution between August 2001 and August 2002. Patients undergoing incidental appendectomy were excluded. Variables collected included age, gender, WBC, CT scan results, and pathologic findings. All pathology reports were reviewed to confirm diagnoses and perforation, with review

Retrospective analysis (PRE group)

Between August 2001 and August 2002, data were compiled on 383 patients presenting to our facility with possible appendicitis. Eighty percent (305 of 383) of patients underwent CT, which was interpreted as positive for appendicitis in 33% (102 of 305). CT during this time period had a 97% (196 of 203) negative predictive value (NPV), which increased to 99% (201 of 203) when accompanied by a normal serum WBC (< 10.5 103/mm3).

Fifty-one percent (196 of 383) of these patients underwent operation

Discussion

Acute appendicitis is the most common cause of an acute abdomen and the need for acute surgical intervention in the Western Hemisphere. The estimated lifetime risk of undergoing appendectomy for suspected acute appendicitis is between 7% and 12%, and approximately 250,000 appendectomies for suspected appendicitis are performed in the US each year.1 Despite advances in surgical diagnosis, the accuracy of clinical diagnosis in acute appendicitis is not > 85% in most series with NA rates of up to

References (37)

  • R. Pieper et al.

    The incidence of acute appendicitis and appendectomy

    Acta Chir Scand

    (1982)
  • R. Pieper et al.

    Acute appendicitis: a clinical study of 1018 cases of emergency appendectomy

    Acta Chir Scand

    (1982)
  • P.M. Rao et al.

    Effect of computed tomography of the appendix on treatment of patients and use of hospital resources

    N Engl J Med

    (1998)
  • J.L. Antevil et al.

    The influence of age and gender on the utility of computed tomography to diagnose acute appendicitis

    Am Surg

    (2004)
  • L. Graff et al.

    False-negative and false-positive errors in abdominal pain evaluation: failure to diagnose acute appendicitis and unnecessary surgery

    Acad Emerg Med

    (2000)
  • M. Colson et al.

    High negative appendectomy rates are no longer acceptable

    Am J Surg

    (1997)
  • P.J. Blind et al.

    The continuing challenge of the negative appendix

    Acta Chir Scand

    (1986)
  • J. Berry et al.

    Appendicitis near its centenary

    Ann Surg

    (1984)
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    • Suspected appendicitis pathway continues to lower CT rates in children two years after implementation

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      Evaluating and quantifying the effect of a policy is important for several reasons, including to ensure that the policy is having the anticipated desired effect, and that the effect is due to the mechanism hypothesized. For example, Antevil and colleagues hypothesized that the negative appendectomy rate would decrease after implementation of their pathway due to more selective use of CT scans.48 However, while the negative appendectomy rate decreased significantly after this intervention, CT scan rates stayed the same, suggesting that the mechanism was not due to more selective CT scan utilization as the authors had concluded.

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    Competing Interests Declared: None.

    The Chief, Bureau of Medicine and Surgery, Navy Department, Washington, DC, Clinical Investigation Program sponsored this report no. S-04-035 as required by NSHSBETHINST 6000.41A. The article represents the personal viewpoint of the authors and cannot be construed as a statement of official Department of the Navy, Department of Defense, or the United States Government policy.

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