Employment of the Novel Laser Direct Alignment Radiation Reduction Technique (DARRT) for Percutaneous Nephrolithotomy Access

Context: Patients with large staghorn calculi are commonly treated with percutaneous nephrolithotomy (PCNL). PCNL access can be technically challenging and has potential to result in significant radiation exposure to both the patient and surgeon. In an attempt to reduce radiation exposure during PCNL, a novel laser Direct Alignment Radiation Reduction Technique (DARRT), combined with ureteroscopic direct visualization, was developed. With this technique renal access is guided by a laser beam sight placed upon the C-arm to assist in proper alignment during needle insertion. Objective: The purpose of this study was to utilize the novel technique and review the operative outcomes in the initial 15 patients who underwent PCNL. Design: The surgeries were performed at a large academic medical center by a single surgeon. Methods: The first 15 patients who underwent the Laser DARRT were retrospectively reviewed. Demographic data were recorded for each patient such as stone burden, degree of hydro- nephrosis, and skin to stone distance. Primary surgical outcomes were fluoroscopy time required for percutaneous renal access and total procedure fluoroscopy time. Secondary outcomes included operative time, estimated blood loss, retreatment rate and stone free status. Patients with residual fragments 4 mm were considered to be stone free. Results: There were 8 male and 7 female patients. Median patient age was 44 years (range 24-82) and stone burden staghorn calculi. The grade of hydronephrosis was minimal in 40% of patients, mild in 14%, and moderate in 46%. The skin to stone distance was 12 cm (5.1-17.4). Access fluoroscopy time was 7 seconds (1.6- 34.5) and total fluoroscopy time was 10 seconds (5-52). The operative time was 180 minutes (118-431), the estimated blood loss was 75 mL (25-350) and the hospital stay was 3 days (1-7). 12 out of 15 patients (80%) were rendered stone free postoperatively. Conclusions: This study demonstrates the safety and efficacy of the Laser Direct Alignment Radiation Reduction Technique for PCNL. Using this technique, total fluoroscopy time was reduced to a median of 10 seconds. This technique employs conventional fluoroscopic techniques which are familiar to most urologists and allows the surgeon to significantly reduce radiation exposure to their patients as well as operating personnel