Managing acute appendicitis

Early appendicectomy was first recommended and performed for non-perforated acute appendicitis in the 1880s. The operation remains the most common in the Western world, accounting for a million hospital days per year in the United States.¹ Despite more than 100 years' experience, accurate diagnosis still evades the surgeon, and avoiding perforation and subsequent complications must be weighed against removal of a normal appendix in patients with other causes of abdominal pain—a “negative” appendicectomy—which has a rate as high as 20%.² This is not a trivial problem. Flum and Koepsell assessed its impact in the United States—length of stay, rate of complications, and mortality (1.5% v 0.2%) were all significantly higher in the negative appendicectomy group, and the annual cost of a negative appendicectomy was calculated at $742m.³

The use of an objective scoring system such as the Alvarado system can reduce the negative appendicectomy rate to 0-5%.⁴ The simple expedient of close observation and repeated re-evaluation has in itself been shown in several studies to reduce the unnecessary exploration rate.⁵ It is inevitable in a climate that values high tech investigations above clinical skills that other modalities have been extensively (and expensively) evaluated in the past decade. Douglas et al randomised 302 patients with suspected acute appendicitis to graded compression ultrasound or clinical evaluation.⁶ The only difference they found was slightly earlier operation in the ultrasound group. The negative appendicectomy rates remained 9% and 11%, respectively, despite restriction of the trial to patients with an Alvarado score of 4 to 8, thus excluding the least and most probable positive cases. The study of over 2000 patients by Zielke et al was more optimistic but still reported 7.6% false positives in the ultrasound group.⁷ It is likely that ultrasonography, which is highly dependent on the clinician who performs it, will be of value only when performed regularly by the same clinician, and in the context of careful, frequent clinical evaluation. Helical computed tomography scanning has greater potential to show alternative pathology and in a prospective randomised study was shown to reduce the negative appendicectomy rate.⁸,⁹ Computed tomography is, however, unlikely to be readily available in most acute surgical settings, certainly in the present NHS.

The single greatest change in surgical practice in the last two decades has been the widespread introduction of laparoscopic techniques in general surgery, and this technology was quickly applied to the problem of acute appendicitis. With the dual advantage, in theory, of accurate minimally invasive diagnosis and rapidity of postoperative recovery, perhaps it is surprising that laparoscopic appendicectomy has not become the universal procedure of choice. A systematic review for the Cochrane Library identified 39 randomised controlled trials of laparoscopic versus open appendicectomy in adults, recruiting more than 4000 patients.¹⁰,¹¹ Laparoscopic appendicectomy halved the number of wound infections, and reduced pain on the first postoperative day, duration of hospital stay, and time to return to work, but at the cost of a threefold increase in the number of postoperative intra-abdominal abscesses. The results in a much smaller number of trials in children were less clear cut. Possibly the increase in abscesses may be obviated if laparoscopic appendicectomy is avoided in patients with probable perforated appendicitis unless done by an experienced laparoscopist.

Laparoscopic appendicectomy comes into its own when there is diagnostic doubt—a special case is that of young women, in whom the diagnostic dilemma is often greatest and in whom endoscopic surgery can be performed if tubo-ovarian pathology is found at laparoscopy. One non-randomised study of parallel groups used the Alvarado score to select young women with suspected acute appendicitis for laparoscopy.⁴ Ten per cent were found to have normal appendixes and were spared a surgical incision, and the normal appendicectomy rate was 0%, compared with 18% in the control group treated on a different surgical unit. This effect in young women was borne out by the systematic review.¹⁰

What should now be recommended for the diagnosis and management of acute appendicitis? Clinical judgment still has a place, especially if an experienced clinician is prepared to re-evaluate doubtful cases at regular intervals: rapid, unexpected perforation is uncommon, and there is no case for rushing to operate in marginal cases. Scoring systems may help, if only by formalising assessment and ensuring attention to detail. Ultrasound has no place as a screening tool but may help in some patients where the diagnosis is doubtful, but computed tomography should be reserved for patients in whom there is suspicion of an alternative diagnosis, especially in elderly or unfit patients. Laparoscopy has a definite place in women, and in others where there is diagnostic uncertainty, although perhaps it is best avoided where the suspicion of perforation is strong. The challenge now is to provide a sufficient number of surgeons skilled in diagnostic and therapeutic laparoscopy on demand, able to deal not only with proved acute appendicitis but also with occasional unexpected findings. Perhaps new approaches to this old common problem will bring us a step closer to a truly consultant based, specialised, acute surgical service in our hospitals.