Robotic-assisted laparoscopic fetal vesicostomy and pyelostomy: a feasibilility study

• Grant number: 06/01899-3
• Support Opportunities: Scholarships abroad - New Frontiers
• Start date: August 01, 2006
• End date: August 31, 2007
• Field of knowledge: Health Sciences - Medicine - Surgery
• Principal Investigator: Carlo Camargo Passerotti
• Grantee: Carlo Camargo Passerotti
• Host Investigator: Alan Retik
• Host Institution: Pessoa Física
• Institution abroad: Harvard University, Cambridge, United States

Abstract

Congenital obstructive uropathy is a common malformation and affects approximately 1 out of 1000 human fetuses. The obstruction may occur anywhere in the urinary tract but most commonly, at the ureteropelvic junction (UPJ) and in the posterior urethra. Obstruction can have devastating consequences on the kidney, producing characteristic changes in the renal parenchyma, collectively known as obstructive uropathy. Obstruction to both kidneys may lead to severe oligohydramnios (depletion of the amniotic fluid around the fetus) and can result in fetal demise. In fetuses with severe obstructive uropathy, the mortality rate is as high as 95%, primarily due to respiratory failure. Of those who survived, approximately 40% will have renal failure. Given the poor outcome, in utero intervention has been advocated in attempt to salvage renal function and restore the amniotic fluid levels to allow for normal pulmonary development. Currently, several methods for urinary decompression have been utilized, including open fetal vesicostomy (drainage of the bladder through a skin opening) and placement of a shunt percutaneously into the bladder. Open fetal vesicostomy is an effective treatment for relieving severe bladder outlet obstruction; unfortunately, it is an invasive procedure associated with high fetal loss rate and maternal morbidity. Less invasive methods of bladder decompression such as percutanous procedures have reportedly decreased the maternal and fetal risk. However, these procedures are fraught with technical problems including occlusion and displacement of the stents and difficulties accessing the fetal bladder. The recent development of minimal access fetal surgery (fetoscopic surgery) provides a promising alternative to the traditional fetal treatments. This technique is based upon adaptation of traditional laparoscopic and endoscopic methods so that it can be used in utero. More recently, Ponsky et al. reported on performing transuterine fetal vesicostomy laparoscopically in a fetal sheep model. It appears that though promising, transuterine fetal vesicostomy is a technically demanding procedure that may be inherently limited by traditional laparoscopic techniques. When used in laparoscopic procedures, the robotic system allows for more efficient and precise surgical manipulation compared to traditional freehand techniques. The robotic system provides improved range of motion to the laparoscopic instruments by allowing for a 270º rotation at the wrist of the instruments. In addition, it provides high-resolution three-dimensional vision and tremor-filtered instrument control with movement scaling. These advantages provided by the robotic system allow for better laparoscopic dissection, tissue handling and suturing. To our knowledge, there has been no prior report of using the robotic system in minimal access fetal surgery. In order to overcome these limitations, we proposed the use of surgical robotic devices in performing laparoscopic transuterine fetal vesicostomy and pyelostomy. We propose to create complete bladder outlet obstruction in 10 fetal sheep at 95 days of gemelar gestation (term 140 days). After 2 days, 5 fetuses will undergo vesicostomy (drainage of the bladder) and 5 will undergo pyelostomy (drainage of the renal pelvis) in order to un-obstruct the urinary tract. The purpose in performing the pyelostomy is to demonstrate that we can use this technique to treat UPJ obstruction (which is more common) as well as bladder outlet obstruction. These gemelar fetuses will be used as controls, where the robotic system will be utilized but no bladder outlet obstruction is created. A C-section will be done prior to the labor to avoid maternal-fetal risk. We define the success of this procedure as the delivery of a live term sheep with a patent vesicostomy or pyelostomy. Renal function will be determined by serum creatinine levels, and histological evaluation will be performed. (AU)