merrix wrote:Neither.
Implants come in 2 or 3 cm increments.
RTE’s should be used to size you correctly when you fall between two cylinder sizes.
And as I understand it, in certain unique situations where the corporotomies have to be made at a lesser depth proximally, an RTE of 1 cm or so may be used to allow the tubing coming from the cylinder to exit the corporotomy and still provide the proximal penetration into the corpora to fully stabilize the cylinders.
At least in the AMS 700 installation instructions, Boston Scientific discourages placing the tubing within the corpora due to the chance of pinching when inflated, making deflation difficult. Instead they recommend using either a special cylinder with a less proximally located tubing exit, or the use of an RTE. The instructions though, don't expressly forbid placing the tubing within the corpora to exit through a less proximal corporotomy.