ABSTRACT
Objective:
To compare the effect of F7.5
ureteroscope and other types of
ureteroscope (F8.5, F9.0, F9.2, F9.6) in the control of intrapelvic
pressure during operation.
Methods:
F7.5 super thin flexible
ureteroscope and other 4 kinds of disposable flexible
ureteroscopes (F8.5, F9.0, F9.2, F9.6) were combined with 3 kinds of ureteral guidance sheaths to form 15
endoscope-sheath combinations. The real outer diameter of each flexible
ureteroscope was measured and the effective ratio of
endoscope-sheath diameter was calculated. The real outer diameter of each soft mirror was measured and the effective sheath ratio was calculated. The irrigation during
lithotripsy was simulated in a 3D printed
kidney model, the irrigation
pressure of 50-500 cmH 2O was set, and the stable intrapelvic
pressure and flow rate were measured. The line chart was drawn and the relationship between intrapelvic
pressure and irrigation
pressure was analyzed by
linear regression. The intrapelvic
pressure between different
endoscope-sheath combinations and different
endoscope groups were compared respectively.
Results:
The ratio of
endoscope-sheath diameter for all combinations ranges from 0.62 to 0.92, with 0.75, 0.68 and 0.62 for the F7.5 flexible
ureteroscopes and F10/12, F11/13 and F12/14 sheath combinations respectively. Intrapelvic
pressure and flow rate showed an approximately linear relationship with irrigation
pressure in all groups. The F7.5 flexible scope with the F10/12, F11/13 and F12/14 sheaths all provided intrapelvic
pressures below 40 cmH 2O. The F12/14 sheath-F7.5 scope combination produced the lowest intrapelvic
pressure of 1.47 cmH 2O at 50 cmH 2O irrigation
pressure and the highest flow rate of 74.24 ml/min at 500 cmH 2O irrigation
pressure. When combined with the F10/12 sheath, only the F7.5 flexible scope was able to maintain a safe intrapelvic
pressure of only 25.90 cmH 2O throughout.
Analysis of the variability of intrapelvic
pressure using the combination of instruments as the grouping variable suggested a significant overall difference( P<0.05).
Analysis of the variability between groups using the different flexible scope as the grouping variable showed that the F7.5 scope group had significantly lower intrapelvic
pressure compared to the other four groups( P<0.05).
Conclusions:
The F7.5 super thin flexible scope has the best intrapelvic
pressure control of the five flexible scopes due to the significantly reduced ratio of
endoscope-sheath diameter for the instrument combination and the
ability to fit a thinner guide sheath while maintaining safe pelvic
pressure.
