A systematic review on urolithiasis in small ruminants according to nutrition-dependent prevalence and outcome after surgery

BACKGROUND AND AIM: Obstructive urolithiasis is a common disease in small ruminants with fatal outcomes if left untreated. Many methods have been established; however, long-term success rates remain unsatisfactory. Four bibliographic databases (PubMed, HeBis, Medline (OvidSP), and Web of Science) were searched to evaluate the prevalence of urolithiasis in small ruminants and long-term outcomes after surgery using a systematic review. The study aimed to give evidence-based data concerning prevalence and success rates after surgery. MATERIALS AND METHODS: The analysis included 24 (total 239) peer-reviewed journal articles dealing with the prevalence of urolithiasis and 16 (total 39) concerning long-term outcomes after surgery. Literature was included if it referred to species, language, availability, and relevant statements to the specific questions, including the presence of control groups. Heterogeneity tests included Χ(2), I(2), and τ(2), respectively. A 95% confidence interval was determined, and effects were estimated using the fixed effect model. Due to a feeding-associated bias, prevalence analysis was conducted for a sorghum-based and a corn-based feeding resulting in a weighted prevalence of 62% and 17%, respectively. Analysis of long-term outcomes after surgical interventions revealed long-term success rates of 15-77% after ultrasonographic tube cystotomy and marsupialization of the urinary bladder, respectively. RESULTS: The prevalence of urolithiasis is strongly associated with feeding and may be calculated as 17% in corn-based rations and 62% in sorghum-based rations. Surgical interventions result in guarded to moderate long-term success rates of 15-66%. Urethral stoma and marsupialization of the bladder provide acceptable long-term success rates with 71-77% but are rather salvage techniques than accepted surgical methods, especially when used in companion animals. CONCLUSION: The development of urolithiasis is mainly influenced by nutrition. Effective prophylaxis of this disease should, therefore, always include advisory service for the owners. Existing surgical techniques should be critically re-evaluated concerning their long-term success rates.