Introduction: The incidence of nephrolithiasis in pregnancy is low; however, the repercussions for both mother and fetus can be significant. Pregnancies with stones have an increased risk of adverse birth outcomes and are associated with significant morbidity. In cases of obstructing nephrolithiasis, intervention may include double-J stent (DJS), percutaneous nephrostomy tube (PCN), or ureteroscopy (URS) with the potential for subsequent procedures such as frequent DJS or PCN exchanges. These interventions often utilize intra-procedural fluoroscopy, which could result in harmful levels of radiation to the fetus. In the present study, we sought to identify the differences in radiation dose per stone episode between initial intervention with PCN, DJS and URS.
Methods: After IRB approval, pregnant patients undergoing a procedure for urolithiasis were retrospectively reviewed at a large multi-center hospital system. Patients who presented during an active pregnancy with acute renal colic and imaging suggestive of obstructing calculi, and who subsequently required an intervention (DJS, PCN, or URS) were included in the analysis. The primary outcome was total fluoroscopy dose per stone episode. Secondary outcomes included fluoroscopic exposure per procedure and average number of procedures required per stone episode. Kruskal-Wallis Rank-Sum Tests were used to assess statistical significance. If significant with a 2-sided p-value of 0.05, post-hoc pairwise testing was performed with a Wilcoxon Rank-Sum test.
Results: 85 patients met inclusion criteria, of whom 40 (55.6%) were managed with DJS, 22 (30.6%) PCN, and 10 (13.9%) primary URS. 13 patients were excluded due to incomplete radiation data. Median total number of procedures was significantly higher in those who underwent initial PCN placement (4.5) compared to primary URS (1) or stent (2) (p <0.001). Those that underwent PCN were more likely to undergo procedures that required radiation (p < 0.001), with a mean radiation per procedure of 61.5 mGy, compared to 0.1 mGy for stent and URS. Total radiation exposure per stone episode was significantly higher in patients that underwent PCN placement (mean 250.8 mGy for PCN, 2.0 mGY for DJS, and 2.2 mGy for URS, p<0.001).
Conclusions: In pregnant patients with suspected acute renal colic requiring intervention, initial PCN placement was associated with a significantly higher number of procedures, higher radiation dose per procedure, and higher total radiation exposure per stone episode compared to DJS and URS.
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