SHOCK WAVE LITHOTRIPSY DURING PREGNANCY: A SUCCESSFUL CLINICAL EXPERIMENT

Abstract

During the last 15 years extracorporeal shock wave lithotripsy (ESWL*) has been used in the treatment of urolithiasis with pregnancy considered a strict contraindication.' There is lack of knowledge concerning the possible effects of shock wave therapy on the development of a human embryo or fetus. We report a case of successful experimental piezoelectric shock wave lithotripsy of an obstructing ureteral stone in an advanced pregnancy. CASE REPORT A 28-year-old multigravid woman presented with severe left flank pain during week 25 of gestation. Ultrasound demonstrated dilatation of the left renal collecting system, including the proximal ureter, due to a 16 x 5 mm. ureteral calculus obstructing the upper ureter (part A of figure). Since pushing or passing the stone by ureteral stents was not successful and recurrent attacks of colic were not relieved by parenteral narcotics, percutaneous nephrostomy was recommended. However, when the patient was confronted with the risks of bleeding, infection, tube displacement and occlusion, and the prospect of urinary diversion with an external appliance for the remainder of the pregnancy, she specifically requested shock wave treatment modalities. After consideration of what is known about the physical properties and biological effects of shock wave application, we ascertained that there was sufficient distance (11 cm.) between the stone./ focus and the uterus, and extracorporeal piezoelectric shock wave lithotripsy was performed. The patient was fully informed about the experimental nature of the treatment modality and gave written, informed consent. Lithotripsy was performed with an ultrasound guided Piezolith 2300,t which provides a small focal zone of 6 mm. in radial and 10 mm. in axial diameter (part B of figure). We delivered 1,600 impulses (focal energy 750 bar) with simultaneous monitoring of the fetus by a second ultrasound scanner and intermittent cardiotocography. No drugs were administered. Alterations of cardiotocography were not seen and no unusual fetal movements were registered. The stone was disintegrated and fragments were discharged spontaneously without further colic. To avoid a steinstrasse, we inserted without difficulty a Double-JS ureteral stent for 3 weeks. X-ray diffraction analysis of the fragments revealed a mixture of two-thirds apatite and one-third struvite. Despite the latter component, no urinary tract infection occurred during gestation. The patient recovered promptly after lithotripsy, and the remainder of the pregnancy and childbirth were free of complications. The female newborn was mature, normally developed, and showed normal size and Apgar score. There have been no adverse sequelae from the intrauterine ESWL at 6-year followup.