What is the role of invasive therapy for nephrolithiasis during pregnancy?

Updated: Jun 21, 2018
  • Author: Chirag N Dave, MD; Chief Editor: Bradley Fields Schwartz, DO, FACS  more...
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Answer

Stone disease in pregnancy poses a particular challenge. In general, conservative management is recommended in the absence of hard indications for surgical intervention such as infection, intractable symptoms, severe hydronephrosis or premature induction of labor.

Regarding imaging modalities, the 2018 EAU guidelines recommend ultrasound as the initial imaging modality of choice. MRI would be a second line choice and low dose CT scans should be saved as a last resort. [1] During pregnancy, radiation may cause teratogenesis or carcinogenesis effects. Teratogenic effects are additive with cumulative doses < 50mGy considered safe. Gestational age is also important to consider (minimum teratogenic risk prior to 8th week & after 23rd week. Carcinogenesis (dose even < 10 mGy present a risk) and mutagenesis (500-1000 mGy doses are required, far in excess of the doses in common radiographic studies) risks increase with increasing dose but do not require a threshold dose and are not dependent on the gestational age. [89]

Stents and percutaneous nephrostomies unfortunately may be tolerated in pregnant individuals and often require more frequent changes as they have the tendency to rapidly encrust stents. [1]

In a retrospective study of 87 pregnant women who received invasive therapy for proximal ureteral calculi following failure of conservative management, Wang et al found that ureteroscopic holmium laser lithotripsy was more effective and better tolerated postoperatively than cystoscopic double-J stent insertion and percutaneous nephrostom—although all three procedures were effective and safe overall. All 87 women completed a full term of pregnancy without serious obstetric or urologic complications. [90]

Of 64 patients who underwent ureteroscopic lithotripsy, 52 (81.3%) had complete fragmentation of calculi, 9 (14.1%) had retrograde calculi fragments that migrated to the renal pelvis, and 3 had inaccessible calculi due to severe ureteral tortuosity. Of 19 women who underwent cystoscopic double-J stent insertion, 17 (89.5%) were successfully treated; two had guide wire insertion failure (10.5%), were subsequently successfully treated with ureteroscopy, and kept their stents in place until delivery.

Complications of the stent placement included 4 patients who developed urinary tract infections, 12 with stent-induced bladder irritation, and seven with other minor complications.

Three of four patients who underwent percutaneous nephrostomy owing to severe hydronephrosis, pyonephrosis, or uncontrolled sepsis were successfully treated. One had extracorporeal shock wave lithotripsy for removal of residual calculi.


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