Increasing stone complexity does not affect fluoroscopy time in percutaneous nephrolithotomy

The aim of this work was to assess whether stone complexity with the Guy's stone score (GSS) is associated with increased intraoperative fluoroscopy time.

We retrospectively reviewed records of 261 consecutive patients undergoing percutaneous nephrolithotomy between 2007 and 2015. Of these, 203 had both preoperative computed tomography for accurate staging and full intraoperative fluoroscopy and radiation dosimetry data were available. Stone complexity was assessed using GSS. A correlation between fluoroscopy time (FT) and GSS was assessed in a univariate and multivariate fashion, including parameters such as age, sex, body mass index (BMI), and number of accesses.

The overall mean FT was 3.69 min [standard deviation (SD) 2.77]. The overall mean Guy's score was 2.5 (SD 1). There was a statistically significant correlation between operative time and FT (r = 0.34, p < 0.0001). There was a trend towards increasing operative time with increasing GSS (r = 0.12, p = 0.08), but there was no statistically significant correlation. There was no correlation between FT and GSS (r = 0.04, p = 0.55). On multivariable regression, accounting for sex, BMI, age, and singular versus multiple accesses, there was no significant correlation between stone complexity and FT (p = 0.893).

In the setting of conscious efforts to reduce intraoperative radiation exposure, increasing stone complexity, as classified by GSS, did not correlate with FT on univariate or multivariate analysis. Thus, treatment of more complex stones may be undertaken without concern that there is an inevitable need for significantly increased fluoroscopy exposure to the patient or operating room staff.