Variations in Contemporary Systems
There are multiple contemporary single-portal endoscopic systems with variations that make each unique. The differences are neither good nor bad, but rather appeal to surgeon preference and familiarity. The three most common variations between modern designs are (1) anterograde versus retrograde knives, (2) linked knife and endoscope versus independent knife and endoscope, and (3) independent cannula systems versus single unit systems.
A retrograde system has the theoretical benefit of being less likely to injure the superficial palmar arch as the surgeon is cutting away from the vascular structure rather than toward it. Antegrade systems, on the other hand, have the theoretical benefit of preventing incomplete distal release because the surgeon maintains visibility of the distal aspect of the TCL and has direct visualization once the distal margin has been transected. Having a single unit which houses both the knife and the endoscope allows for simplicity and direct visualization of the blade at all times. The benefit of having the endoscope and knife separate is that the surgeon has a greater degree of control. Finally, the benefit of having an independent cannula is the ability to maintain the surgical field even after release of ligament. The downside of the cannula is that it adds to the number of components within the system and thus can complicate the procedure.
J Am Acad Orthop Surg. 2022;30(7):292-301. © 2022 American Academy of Orthopaedic Surgeons