Association between ureteral jet dynamics and nonobstructive kidney stones: a prospective-controlled study.

OBJECTIVE: To evaluate the possible alterations in ureteral jet dynamics which inform physicians about ureteral physiology and peristaltism in nonobstructive kidney stone formers with this prospective-controlled study.

MATERIALS AND METHODS: All patients with flank pain eligible for the study underwent Doppler ultrasonoghraphy examination for evaluation of ureteral jet dynamics and non-contrast-enhanced computed tomography for diagnostic reasons. Patients with unilateral nonobstructive lower-pole kidney stone ≤1 cm were defined as group 1 and patients with no evidence of urinary tract stone as group 2. Ureteral jet dynamics were compared between the affected and healthy renal units in group 1 and also between affected renal units in group 1 and all renal units in group 2.

RESULTS: There were 31 and 20 patients in groups 1 and 2, respectively. Mean average jet flow rates (JETave) were significantly lower in affected renal units in group 1 when compared with healthy renal units in group 1 and also when compared with group 2 (10.9 ± 7.6 cm/s, 13.6 ± 5.9 cm/s, and 12.5 ± 3.9 cm/s, respectively; P <.05). Affected renal units were more likely to have continuous jet flow pattern. Odds ratio was 19.3 for patients with JETave <9 cm/s compared with patients with JETave ≥9 cm/s in terms of kidney stone formation.

CONCLUSION: Decreased JETave and continuous jet flow pattern, both of which may refer to decreased ureteral peristaltism, may precede kidney stone formation. Ureteral jet dynamics should be evaluated in patients with previously known risk factors and especially patients with JETave <9 cm/s need close follow-up. However, further prospective cohort trials may enlighten our findings.