The effect of smoking on spontaneous passage of distal ureteral stones.

Background: Animal studies have shown that nicotine affects the peristalsis of the ureter. The aim of the study is to analyze the effect of smoking on spontaneous passage of distal ureteral stones.
Methods: 88 patients in whom distal ureteral stone below 10 mm diameter diagnosed with helical computerized tomography enhanced images were reviewed. Patients were grouped as either smokers (n:33) or non smokers (n:50). Follow-up for spontaneous passage of stones was limited with 4 weeks. Patients did not receive any additional medical treatment other than non-steroid anti inflammatory drugs only during painful renal colic episodes.Two groups were compared with the chi-square test in terms of passing the stone or not. Stone passage was confirmed with either the patient collecting the stone during urination or by helical CT.
Results: Smoking habits was present in 30(34%) patients and the frequency in both groups were similar (smokers: 23(76%) vs non-smokers: 46(79%)). Spontaneous passage of the stone was observed in 69(78%) patients. The two groups were comparable in terms of patient age, male to female ratio and stone size. Stone passage decreased as stone diameter increased. Total stone passage rates were similar in both groups (smokers: 76% vs. non-smokers: 79%) (p > 0.05). Passage of stones > 4 mm was observed in 46% and 67% of smokers and non-smokers respectively. However passage of stones with a diameter ≤ 4 mm were similar in both groups (smokers: 100% vs non-smokers: 92%) (p > 0.05).
Conclusion: Smoking has neither a favorable nor un-favorable effect on spontaneous passage of distal ureteral stones. However, spontaneous passage rates in patients with a stone diameter > 4 mm was lower in smokers. These results should be further confirmed with studies including larger numbers of patients.