Background
Kidney stone disease contributes to a significant proportion of routine urological practice and remains a common cause of worldwide morbidity. The main aim of this clinical-pilot study was to investigate the effect of flexible ureterorenoscopy (FURS) on pre- and peri-operative clinical information, physiological observations and outcome measures.

Methods
Included were 51 patients (31 males, 20 females), who underwent elective FURS, for the treatment of kidney stones.

Pre-operative and peri-operative clinical information, and post-operative physiological observations and outcome measures were collected using a standard case report form. Pre-operative clinical information included age, gender, BMI, previous history of stone formation and hypertension. Pre-operative stone information included the size (mm), Hounsfield units (HU), laterality and intra-renal anatomical location. Peri-operative surgical details included surgical time in minutes; Laser use; Duration and energy of laser; and post-operative stenting. The physiological outcomes measured included systolic and diastolic blood pressure (mmHg), Likert pain score, temperature, heart rate (bpm) and respiration rate (bpm).

Following initial descriptive analysis, a series of Pearson’s correlation coefficient tests were performed to investigate the relationship between surgical factors other variable factors.

Results
A series of significant, positive correlations were observed between; age and surgical time (p = 0.014, r = 0.373); stone size and Hounsfield unit (p = 0.029, r = 0.406); surgical time and duration of laser (p < 0.001, r = 0.702); surgical time and BMI (p = 0.035, r = 0.322); baseline heart rate and Hounsfield unit (p = 0.026, r = − 0.414); base line heart rate and BMI (p = 0.030, r = 0.307).; heart rate at 120-min post FURS and age (p = 0.038, r = − 0.308); baseline pain score and BMI (p = 0.010, r = 0.361); baseline respiration rate and BMI (p = 0.037, r = 0.296); respiration rate at 240-min post FURS and BMI (p = 0.038, r = 0.329); respiration rate at 120 min post FURS and age (p = 0.022, r = − 0.330). Four patients developed post-operative complications (3—UTIs with urinary retention, 1–urosepsis).

Conclusions
We report that following FURS there is an association between various physiological, clinical and surgical parameters. Although these correlations are weak, they warrant further investigation as these may be linked with untoward complications, such as infection that can occur following FURS. This data, however, will need to be validated and reproduced in larger multi-centre studies.