Surgical Parameters Related to Excessive Intrarenal Pressure during Minimally Invasive Percutaneous Nephrolithotomy in the Supine Position: A Prospective Observational Clinical Study

Table 1

Demographics and stone parameters.

Variables		value
Patient number ()	27
Mean age (years)
Gender (male:female)	15 (55.6%) : 12 (44.4%)
Mean BMI (kg/m^2)
Comorbidities
Diabetes mellitus	7 (29.2%)
Hypertension	8 (33.3%)
Cardiovascular disease	2 (7.4%)
Pulmonary disease	2 (7.4%)
Stone laterality (right:left)	15 (55.6%) : 12 (44.4%)
Stone burden (mm^3)
Stone number
Hounsfield unit
Stone location
Pelvis	16 (59.3%)
Upper calyx	4 (14.8%)
Mid calyx	6 (22.2%)
Lower calyx	17 (63.0%)
Multiple	13 (48.1%)
Previous stone treatment history	6 (22.2%)
Staghorn stone	12 (44.4%)
Hydronephrosis	11 (40.7%)
Complete stone free rate	23 (85.1%)
Clinically stone free rate (<2 mm)	25 (92.6%)
Postoperative infection	2 (7.4%)
IRP during different phases of procedures
Initial	(6-51)	Reference
Table tilting	(18-46)	0.376
Upper-pole navigation	(18-46)	0.003
Stone fragmentation	(29-145)	<0.001
Vacuum cleaning effect	(12-45)	0.967

. BMI: body mass index; IRP: intrarenal pressure.