Transuterine large animal testing of a self-expanding vesicoamniotic shunt for fetal LUTO
Michael P. Kurtz, MD, MPH1, Stephanie H. Guseh, MD2, Kyle Costa, BS1, Xuehui Yang, MS1, Duncan Morhardt, MD, PhD1, Arthur Nedder, DVM1, Alan B. Retik, MD1, Caleb P. Nelson, MD, MPH1.
1Boston Children's Hospital, Boston, MA, USA, 2Mass General Brigham, Boston, MA, USA.
BACKGROUND: Placement of a vesicoamniotic shunt has been shown to improve 30-day survival in fetal lower urinary tract obstruction (LUTO), but the two shunts available for clinical use have substantial rates of device-related complications. To address this, we developed and studied a self-expanded silicone nitinol shunt and delivery system. We previously presented data on open shunt placement via laparotomy and hysterotomy. Our lab is now able to place shunts with a closed uterus (transuterine) and we present a video of the procedure.
METHODS: Six fetal lambs had successful creation of a LUTO model at 85-90 days gestation. A twin was kept as control, when present. The lambs underwent ultrasound-guided shunt placement and were sacrificed near term. At harvest, shunt position, shunt dislodgement force, and the vesicostomy tract were analyzed.
RESULTS: All six shunts were successfully placed into the fetal bladder under linear ultrasound guidance. One proximal shunt was engaged into scrotal tissue and was repositioned at the time of placement. All other shunt placements were uncomplicated. All bladders decompressed immediately and decompression persisted to term. There were no cases of dislodgment, abdominal wall hernia, evisceration, membrane separation, chorioamnionitis, tissue ingrowth, clogging, or failure to decompress. One twin control lamb had early demise at 2 weeks after shunt placement. We have seen spontaneous loss of non-operative lambs after contralateral LUTO creation as well.
CONCLUSIONS: We have shown that reliable ultrasound-based placement of a silicone-nitinol self-expanding vesicoamniotic shunt is possible and well-tolerated in lambs. The device has many favorable characteristics compared to plastic double-coiled designs, including lack of dislodgment, lumen patency, and ease of placement. We would anticipate similar benefits in a human trial.
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