There are two microsurgical procedures that have been successful at restoring the flow of sperm through the vas deferens.
The most common, called vasovasostomy (VV), involves stitching the disconnected ends of the vas deferens back together with ultra-fine sutures.
The other reversal procedure, called vaso-epididymostomy (VE) , is performed when inflammation or scarring from the original vasectomy blocks the epididymis – the tubular structure connecting the testes to the vas deferens. In this microsurgical procedure, the blockage is bypassed by surgically connecting the vas deferens directly to the epididymis in a new location.
The inner tube (lumen) diameter of vas deferens is approximately 0.2 mm requiring extreme delicacy in placement of stitches. The lumen of epididymis is 10 times smaller and more fragile. The patency rates (that a connection will stay open after a successful surgery) are a lot better in VV connection compared to VE.