<unk>  Size (cm) Growth rate (cm/yr) Annual rupture risk (%) 3.0-3.9 0.39 0 4.0-4.9 0.36 0.5-5 5.0-5.9 0.43 3-15 6.0-6.9 0.64 10-20 >=7.0 - 20-50 Although the current standard of determining rupture risk is based on maximum diameter, it is known that smaller<unk> s that fall below this threshold (diameter5.5 cm) may remain stable. In one report, it was shown that 10–24% of ruptured<unk> s were less than 5 cm in diameter. It has also been reported that of 473 non-repaired<unk> s examined from autopsy reports, there were 118 cases of rupture, 13% of which were less than 5 cm in diameter. This study also showed that 60% of the<unk> s greater than 5 cm (including 54% of those<unk> s between 7.1 and 10 cm) never experienced rupture. Vorp et al. later deduced from the findings of Darling et al. that if the maximum diameter criterion were followed for the 473 subjects, only 7% (34/473) of cases would have succumbed to rupture prior to surgical intervention as the diameter was less than 5 cm, with 25% (116/473) of cases possibly undergoing unnecessary surgery since these<unk> s may never have ruptured. Alternative methods of rupture assessment have been recently reported. The majority of these approaches involve the numerical analysis of<unk> s using the common engineering technique of the finite element method (FEM) to determine the wall stress distributions. Recent reports have shown that these stress distributions have been shown to correlate to the overall geometry of the<unk>  rather than solely to the maximum diameter. It is also known that wall stress alone does not completely govern failure as an<unk>  will usually rupture when the wall stress exceeds the wall strength. In light of this, rupture assessment may be more accurate if both the patient-specific wall stress is coupled together with patient-specific wall strength. A non-invasive method of determining patient-dependent wall strength was recently reported, with more traditional approaches to strength determination via tensile testing performed by other researchers in the field. Some of the more recently proposed<unk>  rupture-risk assessment methods include:<unk>  wall stress;<unk>  expansion rate; degree of asymmetry; presence of intraluminal thrombus (ILT); a rupture potential index (RPI); a finite element analysis rupture index (FEARI); biomechanical factors coupled with computer analysis; growth of ILT; geometrical parameters of the<unk> ; and also a method of determining<unk>  growth and rupture based on mathematical models. The post-operative mortality for an already ruptured<unk>  has slowly decreased over several decades but remains higher than 40%. However, if the<unk>  is surgically repaired before rupture, the post-operative mortality rate is substantially lower: approximately 1-6%.
Abdominal aortic aneurysm
Appendicitis
Superior mesenteric artery syndrome
Splenic infarction
Aortoenteric fistula
Postcholecystectomy syndrome
Renal vein thrombosis
Spontaneous bacterial peritonitis