3-S Locking Pin Casting Methods

3-S Locking Pin Casting Methods

Robert Schiff

Hello all,
       I am currently a prosthetic resident with a question or poll
regarding casting methods for Silicone suction with locking pin casting
methods. I was taught to distract the limb via the pin during a normal one
or two stage casting method. This was done so that the soft tissue could be
somewhat distracted. The facility that I am currently studying under has two
practitioners each of whom do a different casting method for these sockets.
One puts the liner on the pt. and casts with a three stage cast over the
liner, modifies appropriately and proceeds to check socket, etc. The other
casts the limb without a liner, modifies as he would a PTB but adds a good
couple of inches distally, pulls check socket over a designated sacrifice
liner and then during the check socket fit he uses a D-ring and pin to hold
the limb while he alginates the distal buildup. I left out some details but
that is the main idea. While I find his method (alginate) to be extremely
effective it is much more time consuming and involved that the other route.
It is also more expensive(sacrifice liners and alginate). I can't, however,
seem to justify the first method by means of achieving ture total contact in
the socket. The distraction of tissue seems to be the opposite of what
actually happens when the socket is donned. It would seem that when the
socket is donned the tissue would tend to migrate proximally, thus, not
matching with the original casting which was distracted.

The practitioner and I have had numerous discussions about this. I guess the
point of this is to ask for other's techniques and thoughts as to how the
distraction technique is actually supposed to work and achieve total contact.
 Any thoughts are appreciated.

Thanks,
Robert