purchase.
The most common way to insert a continuous nerve block is to feed
the catheter through a needle, known as the catheter-through-needle
(CTN) technique. This requires several steps and may result in leak-
age when the needle is removed, since it leaves a larger hole than the
inserted catheter. The latest catheter systems, which reduce leakage
and improve ease of placement, change how you insert the catheter.
Catheter-over-needle (CON) systems leave the catheter in place after
the needle is withdrawn. Since the catheter is making the larger punc-
ture, not the removed needle, the technique results in less leakage. It's
also a single-step procedure, which some say makes continuous nerve
block insertion more like single-shot blocks. Evidence is still limited
for the efficacy of CON systems versus the more traditional CTN
