Management of Ureteral Calculi Using Ultrasound Guidance: A Radiation Free Approach

Overview

Kidney stones are very common, and can inflict a significant degree of pain and renal damage. Some stones become obstructed in the ureter, the tube that drains the kidney. In order to remove these stones, an Urologist and their team use fluoroscopic guidance to do so, this involves continuous X-ray. Flouroscopy delivers a significant dose of radiation to the patient, as well as the health care team, which has been shown to have serious health consequences. Previous studies have shown that in certain populations, like pregnant women, stones can be managed using ultrasound guidance. The investigators propose that mid and distal ureteral stones could be managed using ultrasound guidance in conjunction with conventional stone removal techniques (ureteroscopy, lithotripsy, and ureteral stent placement), in lieu of fluoroscopy, thereby minimizing radiation to healthcare staff and patients. The investigators hypothesize that distal ureteral stones can be identified and efficiently fragmented and removed under ultrasound guidance in a safe and effective manner without the use of radiation.

Patients will be enrolled and consented for this study in our Urology Clinic at Dartmouth Hitchcock Memorial Hospital and randomized prospectively to fluoroscopic versus ultrasound guided groups. A computer randomization program will be used to randomize the patient to the test or control group. Randomization will take place after they have consented to participate in the study, and the case will be booked accordingly. Consent to participate in this study will be obtained at the patient's followup appointment. At the time of the initial clinical encounter they will be provided with the consent form and information regarding the study. Once they have had the chance to look this over they will be contacted about whether they would consent to be in the study. If so, they will be randomized and the consent form signed on the morning of the procedure. Each group will consist of 25 patients. This pilot group size was determined based on feasibility of recruitment in the study period and funding availability. All patients will receive preoperative antibiotics selected in accordance to their previous urine culture sensitivities and their respective allergies where applicable. Intraoperatively, all patients will be placed in the dorsal lithotomy position. All patients will be under general anesthesia, in both treatment arms, this is standard of care. All procedures will begin with standard cystourethroscopy, removal of the previous ureteral stent, and passage of a wire proximally into the renal pelvis. The ultrasound group will undergo intraoperative transabdominal ultrasonography by a designated ultrasonographer, and the presence of the wire, and later the ureteral stent, within the renal pelvis will be confirmed via ultrasound in all patients. The control group will undergo standard verification of wire and stent placement via fluoroscopy. Operative time as well as radiation fluoroscopy time will be recorded and compared between the two groups. At our institution, this procedure is scheduled for 140 minutes of OR time based on previous experience by our group and this individual surgeon. Stone free rate will be determined at one month post operatively with a KUB and renal ultrasound and compared between groups. Intraoperatively, if there is concern for poor visualization, lack of progress, or technical difficulty related to the use of intraoperative ultrasound, or any other safety concerns, then this technique will be abandoned and conventional fluoroscopy will be used for this patient group. This will be apparent in the first 15 - 30 minutes of the procedure.