ED50 of Intrathecal Hyperbaric 2% Prilocaine in Transperineal Magnetic Resonance Imaging-Transrectal Ultrasound Fusion Guided Biopsy

Prostate biopsy to diagnose or exclude cancer is currently performed an estimated one million times annually worldwide. In this method, the operator images the prostate using ultrasound, as performed for the past several decades; while thus viewing the prostate, the MRI of that prostate, which is performed beforehand and stored in the device, is fused with real-time ultrasound using a digital overlay, allowing the target(s), previously delineated by a radiologist, to be brought into the aiming mechanism of the ultrasound machine. The fusion results in creation of a three-dimensional reconstruction of the prostate, and on the reconstructed model, the aiming and tracking of biopsy sites occurs. This method needs for sedation/general/ spinal anesthesia because of patient discomfort with the transperineal approach of the biopsy needle passing through the perineum.

Even though the MRI/ultrasound fusión prostate biopsy is widespread used, the anaesthetic techniques for this procedure are not standardised. Hyperbaric prilocaine is an amide-type local anesthetic widely used in short surgical procedures showing its efficacy for outpatient surgery. The proposed intrathecal doses of prilocaine for various surgical procedures range from 10 to 80 mg. Thus, even though the drug is in clinical use, optimal doses of HP required for specific types of surgery warrant further refinement. The aim of the present study was to determine the ED50 and ED90 of intrathecal HP for patients undergoing undergoing ambulatory MRI/ultrasound fusión prostate biopsy.