The risk factors for the development of gall stones are multiple which a reason for its high prevalence. Past history of major surgeries does carry some of the biological causations of the gall stones like prolonged fasting during the perioperative period and post-operative hyperbilirubinemia, effects of stress in the gall bladder, and bile flow. However, there have not been recent studies to redefine the etiology of gall stone and history of major surgery. Meanwhile, some of the studies are found be of a great value for the background of this study.
A study published by J M Little and J Ivramovic in 1991 showed that the major abdominal surgery had a statistically significant difference in a cumulative prevalence of the gall stone compared to those who did not undergo any surgery. However, the exact mechanism behind the formation of the stone was not revealed but the sludge formation during fasting was assumed to be the common pathways. L Bolondi, S Gaiani have ultrasonographically assessed the prevalence of sludge in a group of 48 fasting patients after gastrointestinal tract surgery with a period of fasting lasting for 7 to 10 days. It showed the presence of gall stones with different ultrasonographic patterns in three sludge positive patients after the end of six months. They concluded in the early postoperative period there is a high risk for sludge development and that in some cases sludge may subsequently evolve into gall stones.
Another cross-sectional study by A F Attili,E Scafato showed that Prevalence of gallstone was higher among subjects who had an overnight fasting period of over 12 hours than subjects with that of less than 12 hours. H M Bloch et al studied the effects of fasting and composition of gall bladder, where the mean cholesterol saturation index was significantly greater after a 15 hour fast (1.35+0.08) than after a 10 hour fast (105+0.10). The cholesterol saturation index is the ratio of the cholesterol of the sample to the maximum soluble cholesterol of that sample. In the study, it was determined by using the criteria of Hegardt and Dam. The saturation index of greater than 1 represents the cholesterol is supersaturated and forms gall stones. Henceforth, the findings suggested that fasting for between 10 to 20 hours increases the risk for gallstones formation. Another study by Lee et al where they followed the 94 patients with biliary sludge for the mean of 37.8 months. It was found that 8.3% developed asymptomatic gall stones and 6.3% underwent cholecystectomy.
Another prospective study by Christine Evans et al followed 180 patients following major operations found an incidence of 3.7% severe jaundice and 16.5% mild jaundice (serum bilirubin 1.5-4 mg/dl) and a study by Stefan Stenderet al followed 61,212 patients for 34 years, which showed that the risk for gall stone disease is significantly higher in population with bilirubin level in 10th decile (geometric mean 1.34 gm/dl). Though the previous studies have examined the relationship between fasting and the formation of gallstones, none of them examined the direct relationship between any major surgeries and the incidence of gallstones. They also did not study the other factors like the effects of stress, drugs during surgeries and anesthesia on the gall bladder, and the bile flow. However, they have given enough background to establish a hypothesis that any major surgery can be a significant risk factor for the development of gallstones. However, there is no widely accepted consensus on the grading of surgery so by major surgery we mean all surgeries done under general or regional anesthesia and involves procedures in abdominal cavity.
With our observation of the evidence, it indicates that any major surgery may itself is an important determinant of the gallstone formation soon after the surgery and so a study can address this gap of the knowledge. A case-control study can help us assess the past history of major surgery as a significant risk factor for gallstone disease. Any significant findings will warrant other higher studies like cohort study for a detailed assessment of the cause. It has been evident that prolonged fasting or fasting over 10-12 hours imposes a risk factor for gallstone disease. It has also been established that major gastrointestinal surgery, hyperbilirubinemia is also a risk factor for gallstone disease. However, there is a clear gap of knowledge whether any major surgery with similar biological causation imposes a risk factor for gallstone disease or not. The rationale of the study is to look over this lack of knowledge.
The gall stone disease is itself a major economic burden to a lot of patients and the development of symptomatic gallstone in patients who have undergone major surgery in the past few years would be distressing to the patients and relatives. Even if few people after major surgery develop gall stones in future, and those at such risks could be identified, then we could institute surveillance ultrasonography or medical prophylactic measures like ursodeoxycholic acid.