Emergency General Surgery

Who Has the Higher Score Wins… the Appendectomy

Close your eyes… relax… and think about surgery…

Which is the first surgical procedure you dream of? We bet appendectomy…

After all, it is one of the most performed surgical procedures ever, and it is one of the first operations residents are allowed to do.

However, appendectomies (as well as all the other surgical procedures) require a precise indication: in this case acute appendicitis (yeah, we know about appendiceal neoplasms, but for the post’s sake we will go on as they do not exist). It seems a little bit trivial and obvious, but it isn’t. It is true that acute appendicitis is the most common abdominal emergency requiring surgery. However, in literature, the negative appendectomy rate (NAR), defined as the percentage of patients operated for suspected acute appendicitis having pathologically normal appendices, is considered acceptable up to 20-25%, and even higher in young women.

Twenty-five percent for God’s sake!!! That means one patient out of four undergoes surgery for nothing!!! And it is acceptable!!!

But, why is the negative appendectomy rate so high?

The correct diagnosis of acute appendicitis may be tricky sometimes. Though, it does not explain the high NAR. In our opinion, possible answers are:

  1. in young women a pathological process involving the right ovary and/or tuba, as well as a pelvic inflammatory disease, may mimic quite well the clinical picture of acute appendicitis;
  2. the same can be said in the elderly about right colonic cancer;
  3. appendiceal neoplasms may manifest as acute appendicitis as well;
  4. sometimes doctors (in general), when in doubt, are scared to ask for a CT scan in young patients because of radiation exposure (be clear that we do not support extensive use of CT scans). Therefore, patients underwent surgery without a clear diagnosis;
  5. not all radiologists (as well as surgeons and emergency department doctors) are able to detect the appendix with ultrasound (it should be said that sometimes it is not possible at all);
  6. from the legal point of view, it is easier to explain to the judge why you brought a patient with a negative appendix to the OR than why you didn’t if the patient had acute appendicitis;
  7. “Fuck it… I’m a surgeon… I want to operate… so what?! I want to cut something… positive, negative, and all that’s between…”.

So then, how could we decrease the NAR?

  1. Using scores;
  2. Using algorithms and flowcharts;
  3. Learning how to properly perform appendix ultrasound (yes, even if you’re a surgeon).

Scores, algorithms, and flowcharts allow us to evaluate a patient objectively, and they give us a strong weapon to use in court (if needed). In fact, we can demonstrate we acted with a specific scientific method. Moreover, the use of scores decrease the use of imaging, the number of admissions, and the NAR.

Many scores have been proposed to help in the diagnosis of acute appendicitis. The most famous are, in chronological order, the Alvarado (MANTRELS) score, the Appendicitis Inflammatory Response (AIR) score, the RIPASA score, and the Adult Appendicitis Score (AAS).

All these scores consider the patient’s history, signs and symptoms, and laboratory results, and they resemble one another.

The Alvarado score was created in 1986, and it is well-known ever since, and possibly the most commonly used. It differentiates patients into three categories depending on the risk of having acute appendicitis: score 1-4 (low risk), score 5-6 (intermediate risk), and score 7-10 (high risk) An Alvarado score <4 has a sensitivity of 99% to exclude acute appendicitis, where is not sufficiently specific to bring a patient directly to the OR (sensitivity 82%). In fact, A low Alvarado score (<4) has more diagnostic utility to “rule out” appendicitis than a high score (≥7) does to “rule in” the diagnosis. Nevertheless, it performs poorly in elderly patients, in pregnant women, and in HIV-positive patients. Moreover, it is not able to differentiate complicated from uncomplicated acute appendicitis.

The AIR score proved to be a good tool to stratify the risk of acute appendicitis in patients with acute abdominal pain. It classifies patients into low-risk (score 0-4), intermediate-risk (5-8), and high-risk (score 9-12). The AIR score has a high sensitivity for acute appendicitis, and particularly for advanced cases (98%). Moreover, its high-risk cut-off (i.e. AIR score ≥9) has good specificity for appendicitis (97%).

The RIPASA score is quite complex to calculate since it has 14 items to evaluate. Its optimal cut-off threshold score is 7.5. At this point it reaches acceptable sensitivity (85-88%) and specificity (67-70%), outperforming the Alvarado score. However, it does not allow stratification of patients’ risk, and it performs better in the Asian and Middle Eastern populations.

The Adult Appendicitis Score includes 7 items, but most of them have many other parameters to be considered. Therefore, its structure may seem a little bit elaborated and complex, making its use not user-friendly. The AAS classifies patients into three risk groups: low-risk (score ≤10), intermediate-risk (score 11-15), and high-risk (score ≥16). The score achieves a sensitivity of 49% and specificity of 93% if AAS ≥ 16, and sensitivity of 95% and specificity of 60% if AAS ≥ 11.

So then, which scoring system should be chosen as a standard?

A recent paper stated that AAS works best for women (specificity 63% using a cut-off ≤8), whereas the AIR score performs best for men (specificity 25% using a cut-off ≤2). However, they focused more on finding patients who do not have acute appendicitis rather than those with acute appendicitis.

Many more studies compared scores between each other. Sometimes one performs better than the other, other times is the other way around. Some work better in excluding patients without acute appendicitis, others in detecting those with acute appendicitis.

In our opinion, the most important thing is not which score you decide to use, but to use at least one. Some of them are more user-friendly than others (it is true that nowadays with smartphones you have all the scores you want at your fingertips, but they should be easy to remember and to do). Also, some scores cannot be performed everywhere (e.g. Kalan et al. modified the Alvarado score because in their hospital the differential blood count was not performed on a routine basis), so you need to consider that too.

We advocate the use of a score that allows you to stratify patients’ risk. These scores allow you to safely discharge patients falling in the low-risk group, and to reserve more advanced imaging techniques and/or surgery to those included in the high-risk group.

Anyway, always remember that scores do not diagnose acute appendicitis, they can just help you through your decision-making process. In fact, in our opinion, scores should not be used on their own, but in conjunction with at least ultrasound.

Beware that all that was reported above does not necessarily apply to pediatric patients.


  1. Di Saverio S, et al. Diagnosis and treatment of acute appendicitis: 2020 update of the WSES Jerusalem guidelines. World Journal of Emergency Surgery 2020;15:27.
  2. Alvarado A, et al. A practical score for the early diagnosis of acute appendicitis. Ann Emerg Med 1986;15:557-64.
  3. Andersson M, et al. The appendicitis inflammatory response score: a tool for the diagnosis of acute appendicitis that outperforms the Alvarado score. World J Surg 2008;32:1843-9.
  4. Chong CF, et al. Development of the RIPASA Score: a new appendicitis scoring system for the diagnosis of acute appendicitis. Singapore Med J 2010;51:220-5.
  5. Sammalkorpi HE, et al. The introduction of adult appendicitis score reduced negative appendectomy rate. Scandinavian Journal of Surgery 2017;106:196-201.
  6. Scott AJ, et al. Risk Stratification by the Appendicitis Inflammatory Response Score to Guide Decision-Making in Patients With Suspected Appendicitis. Br J Surg 2015;102:563-7.
  7. RIFT Study Group on behalf of the West Midlands Research Collaborative. Evaluation of appendicitis risk prediction models in adults with suspected appendicitis. Br J Surg 2020;107:73-86.
  8. Kalan M, et al. Evaluation of the modified Alvarado score in the diagnosis of acute appendicitis: a prospective study. Ann R Coll Surg Engl 1994;76:418-9.
How to Cite This Post

Bellio G, Marrano E. Who has the higher score wins… the appendectomy. Surgical Pizza. Published on July 7, 2020. Accessed on May 7, 2022. Available at [https://surgicalpizza.org/emergency-surgery/who-has-the-higher-score-wins-the-appendectomy].


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