Existing guidance on this topic is based on older and smaller studies, and there remains variation in practice. This review of database outcomes of 1168 out of 3081 (38%) patients who underwent early intervention after presentation to nine Canadian emergency departments enhances the evidence base for a risk stratified approach. Early intervention included stone basketing (40.5%), laser lithotripsy (34.7%) and stent placement (9.1%). Those with stones <5mm had more treatment failures compared to trial of spontaneous passage (31% vs. 9.9% failure and 38% vs. 19% re-visits to ED), irrespective of location. Large stones (7mm or more) in any location did better with intervention. Location mattered most for 5 to 6.9mm stones, those in the mid or proximal ureter had more treatment failures with spontaneous passage (55.5% vs. 37.4%) whereas either approach yielded similar outcomes for those in the distal ureter. Apart from stone width the severity of hydronephrosis was correlated with failure of spontaneous passage. This data has its limitations as it is non-randomised and does not consider the effect of analgesics, alpha blockers or stents and instead evaluates increased morbidity from ED re-visits, hospital re-admission, pain and subsequent intervention. Whilst early intervention is intuitively attractive, this study illustrates the need for a risk-stratified approach to prevent increased morbidity from intervention in patients who may not need it. Early intervention when unnecessary can have detrimental effects.
