Robot-assisted pelvic urologic surgeries: is it feasible to perform under reduced tilt?

Effects of the angle of head-down tilt on dynamic cerebral autoregulation during combined exposure to cephalad fluid shift and mild hypercapnia

Astronauts experience combined exposure to a cephalad fluid shift and mild hypercapnia during space missions, potentially contributing to health problems. Such combined exposure may weaken dynamic cerebral autoregulation. The magnitude of cephalad fluid shift varies between individuals, and dynamic cerebral autoregulation may be affected more by greater cephalad fluid shift during combined exposure. We evaluated the dose-dependent effects of head-down tilt (HDT) on dynamic cerebral autoregulation during acute combined exposure to HDT and 3% CO2 inhalation. Twenty healthy participants were randomly exposed to three angles of HDT (-5°HDT+CO2, -15°HDT+CO2 and -30°HDT+CO2). After 15 min of rest, participants inhaled room air for 10 min in a horizontal body position, then inhaled 3% CO2 for 10 min under HDT. The last 6 min of data were used for analysis in each stage. Arterial pressure waveforms were obtained using finger blood pressure, and blood velocity waveforms in the middle cerebral artery were obtained using transcranial Doppler ultrasonography. Dynamic cerebral autoregulation was evaluated by transfer function analysis between waveforms. Statistical analysis was performed by two-way repeated-measures analysis of variance. The index of transfer function gain in the low-frequency range increased significantly with -15°HDT+CO2 and -30°HDT+CO2, but no changes were seen with -5°HDT+CO2. Phase in the low-frequency range decreased significantly with all three protocols. These results of significant changes in indexes of both gain and phase during combined exposure to steep HDT (-15° to -30°) and 3% CO2 inhalation suggest weakened dynamic cerebral autoregulation with the combination of moderate cephalad fluid shift and mild hypercapnia.

Comparison of Trendelenburg Angles in Vaginal, Laparoscopic, and Robotic Uterovaginal Apical Prolapse Repairs

STUDY OBJECTIVE

To compare the Trendelenburg angle used in laparoscopic uterovaginal apical prolapse repairs with the angles used in vaginal and robotic uterovaginal apical prolapse repairs.

DESIGN

Prospective, multicenter cohort study from May 2015 to December 2016.

SETTING

Two academic teaching hospitals.

PATIENTS

Sixty patients who underwent vaginal high uterosacral ligament suspension, laparoscopic sacrocolpopexy, or robotic sacrocolpopexy performed by 6 surgeons board-certified in female pelvic medicine and reconstructive surgery.

INTERVENTIONS

Measurement of Trendelenburg angle and time spent in Trendelenburg during surgery.

MEASUREMENTS AND MAIN RESULTS

Twenty patients were enrolled in each procedure group. The median maximum angle of Trendelenburg was significantly greater in the laparoscopic group (22° [20-25]) than in the vaginal group (15° [6-19]; p <.001) and the robotic group (19° [16-21]; p = .02). The participants in the laparoscopic group spent significantly more time overall in Trendelenburg (176 minutes [143-221]) than those in the robotic group (150 minutes [127-161]; p = .01) and those in the vaginal group (120 minutes [86-128]; p <.001). The participants in the laparoscopic and robotic groups spent similar amounts of time in maximum Trendelenburg (116 minutes [52-164] and 117 minutes [61-134], respectively; p = .56), whereas the participants in the vaginal group spent significantly less time in maximum Trendelenburg (10 minutes [7-38]) than those in the laparoscopic group (p <.001). The total median operative time was highest for the laparoscopic approach (211 minutes [173-270]), followed by the robotic approach (181 minutes [165-201]) and the vaginal approach (162 minutes [128-186]; p = .008).

CONCLUSION

The median maximum angle of Trendelenburg was highest in laparoscopic sacrocolpopexy-followed by robotic sacrocolpopexy-and lowest in vaginal high uterosacral ligament suspension. Patients who underwent robotic sacrocolpopexy spent less time in Trendelenburg than those who underwent the laparoscopic approach. Prolonged, steep Trendelenburg is often not required for any of the 3 surgical procedures, but a vaginal approach should be considered for those at high risk of complications from Trendelenburg position.