Four-dimensional ultrasound guidance for pelvic floor Botulinum toxin-A injection in chronic pelvic pain: a novel technique

Objective Botulinum toxin-A (BoNT-A) is used in the treatment of pelvic floor muscle overactivity associated with chronic pelvic pain (CPP) when conservative methods such as physiotherapy are not effective or appropriate. Traditional injection techniques require finger-guided palpation of pelvic floor muscles with concurrent insertion of the needle. The aim of this study was to describe a novel technique for the injection of BoNT-A into the pelvic floor musculature using four-dimensional ultrasound (4D-US) guidance. Methods Thirty-one BoNT-A injections were performed using the new technique between October 2013 and January 2016, on women scheduled to have BoNT-A injection for pelvic floor muscle overactivity and CPP. The pelvic floor was assessed by 4D-US. A test injection of saline was performed to confirm location of the needle, then BoNT-A was injected into the muscle under ultrasound guidance, using 4D-US to confirm that the fluid expanded and tracked along muscle fibers. Results The saline test confirmed correct location of the needle following a median of 1 (range, 1-3) attempt at needle placement. In all 31 instances, satisfactory injection of BoNT-A, with 4D-US confirmation of fluid expansion within the muscle body, was performed. Conclusions Injection of BoNT-A under 4D-US guidance is feasible and allows accurate placement into the target muscle in women with pelvic floor muscle overactivity associated with CPP. This technique may provide a safer alternative to finger-guided methods, owing to a lower likelihood of operator needle-stick injury. Copyright (c) 2017 ISUOG. Published by John Wiley & Sons Ltd.