文献考察1):画像診断が発達した現在ではnegative appendectomy rateは2%.
Am J Surg. 2004 Dec;188(6):748-54. Are negative appendectomies still acceptable?
Jones K, Pena AA, Dunn EL, Nadalo L, Mangram AJ.
BACKGROUND: The goal was to ascertain if there was a significant change in the negative appendectomy (NA) rate in our community hospital with the increased use of computed tomography (CT). METHODS: This was a retrospective chart review of all appendectomies for acute disease performed at our institution from January 2000 to December 2002. There is no established protocol; therefore, CT scans were performed at the discretion of the involved physicians. The results of the physical exams, CT scans and pathology were recorded. RESULTS: Three hundred eighty-nine appendectomies were performed for appendicitis. There was a progressive increase in the use of CT: 52% in 2000, 74% in 2001, and 86% in 2002. There was also a decrease in the NA rate over the 3 years: 17% in 2000, 9% in 2001 and 2% in 2002. The perforated appendicitis rate decreased from 25% in 2000 to 9% in 2002. CONCLUSION: The appropriate utilization of CT scan as an aid in the diagnosis of acute appendicitis should decrease the NA rate to 2%.PMID: 15619494
文献考察2):CT活用でnegative appendectomy rateは4%.
Am J Gastroenterol. 1998 May;93(5):768-71. Appendicitis: the impact of computed tomography imaging on negative appendectomy and perforation rates.
Balthazar EJ, Rofsky NM, Zucker R.
OBJECTIVES: The purposes of this study were to investigate the use of computed tomography (CT) imaging in patients with suspected acute appendicitis and to evaluate the impact of CT on negative appendectomy and perforation rates. In patients clinically diagnosed of acute appendicitis the reported overall negative appendectomy rate is about 15-20%; 10% in men and 25-45% in women of childbearing age. This is associated with a perforation rate of 21-23%. METHODS: This is a retrospective analysis of 146 consecutive patients presenting with clinical symptoms suspicious of appendicitis over a 2-yr period in whom CT examinations were performed before therapy was instituted. The overall negative appendectomy and perforation rates were calculated for the entire group, as well as for the 54 women aged 15-50 yr in the childbearing cohort. RESULTS: The negative appendectomy rate was 4% in 122 patients operated on and the perforation rate was 22%. Among 36 women 15-50 yr of age operated on, the negative appendectomy rate was 8.3% and the perforation rate was 19%. Surgery was avoided in 24 patients, 18 of whom were women of childbearing age. CONCLUSIONS: The judicious use of CT imaging in patients with equivocal clinical presentation suspected of having appendicitis led to a significant improvement in the preoperative diagnosis. It resulted in a substantial decrease in the negative appendectomy rate compared to previously published reports, without incurring an increase in the perforation rate.PMID: 9625125
文献考察3):急性虫垂炎の57%にガスを認め,ガスで充満した虫垂炎は7%.
Clin Radiol. 1997 Oct;52(10):750-4. Appendiceal and peri-appendiceal air at CT: prevalence, appearance and clinical significance.
Rao PM, Rhea JT, Novelline RA.
AIM: Appendiceal air has been reported as both a sign of appendicitis and of a normal appendix both at plain radiography and computed tomography (CT). It is the aim of this investigation to determine the prevalence, range of appearances, and significance of appendiceal and peri-appendiceal air at CT. PATIENTS AND METHODS: Appendiceal CT scans of 100 patients with proven appendicitis and 100 patients with a normal appendix were reviewed for the presence of appendiceal and peri-appendiceal air. All cases were correlated with surgical and pathological findings or clinical follow-up. RESULTS: In 100 CT cases of appendicitis, appendiceal and/or peri-appendiceal air was present in one or more forms in 31% of cases. When present, it appeared as intraluminal air bubbles (38.7%) or air-fluid levels (22.6%), appendolith air (41.9%), intramural air (16.1%), peri-appendiceal air bubbles (12.9%), or extraluminal air-fluid level(s) (29.0%). Intramural and extraluminal air correlated with perforation in 60% and 100%, respectively. In 100 CT cases of a normal appendix, air was present in 57%. It was always intraluminal and appeared as small bubbles of air (52.6%), a tubular-shaped air collection (43.9%), or as an air-fluid level (3.5%). The appendiceal lumen was either airless (43%), or minimally (32%), moderately (18%), or completely filled with air (7%). CONCLUSION: Air is a common finding at appendiceal CT in both the normal and inflamed appendix. Intraluminal air is seen in both appendicitis and normal appendices, and cannot be presumed to indicate a patent lumen and thus a normal appendix. Appendolith, intramural and peri-appendiceal air appear diagnostic of appendicitis.PMID: 9366533
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