The Role for Active Monitoring in Urinary Stones: A Systematic Review

Abstract

All urinary stones may not need prompt active treatment. The aim of our study was to identify urinary stones that can be actively monitored safely. We performed a systematic review of the natural history and the role of active monitoring for urinary stones. Thirty-seven studies have selected. Of symptomatic ureteral calculi <4 mm, 38% to 71% will pass spontaneously while only 4.8% of stones <2 mm will need intervention during surveillance. Follow-up with history, physical examination, urinalysis, and plain radiography every 2 weeks for 1 month is necessary. If spontaneous passage does not occur within this period, intervention is recommended. When shockwave lithotripsy for caliceal stones is prospectively compared with observation, there is no difference in stone-free rates (28% vs 17%), need for additional treatment (15% vs 21%), or visits to a general practitioner (18.5% vs 20.8%). Patients under observation may need more invasive procedures and may be more commonly left with residual stone fragments >5 mm (58% vs 30%). Isolated, nonuric acid calculi <4 mm may be most amenable to active monitoring. Physical examination, urinalysis, and CT scan performed on an annual basis up to year 2 or 3, followed by intervention, are recommended. Lower pole stones <10 mm could be actively monitored on an annual basis by alternating ultrasonoraphy with CT scan, provided the patients are adequately informed. Up to 58.6% and 43% of patients with residual fragments after shockwave and percutaneous lithotripsy, respectively, may become symptomatic or require intervention during follow-up. Noninfected, asymptomatic fragments, <4 mm postextracorporeal lithotripsy, and <2 mm postpercutaneous surgery could be followed expectantly on an annual basis, in combination with medical therapy. Active stone monitoring has a certain role in the treatment of patients with urinary stones. The success is largely dependent on the stone size, location, and composition, as well as the time after the diagnosis. Medical therapy is a useful adjunct to observation.