There are two saying that I keep in mind when looking for leaks in an elevated vacuum prosthesis.
Alan Watts, the Eastern philosopher, once advised, “Don’t just do something…..Stand there!!!”
The second saying is anonymous: “Remember that you always find your lost keys in the last place you look.”
A colleague of mine was trying to please a patient who complained that the Harmony system took too long to pump up. She wanted to try something else. He changed her over to the Limb Logic. The patient said the Limb Logic never gave her enough vacuum. they went back to Harmony. The prosthetist even tried three different suspension sleeve models in an attampt to get better vacuum. Since it continued to leak with each sleeve, he decided that it was not a sleeve problem and went back to the original sleeve. He then asked for my help. We took Alan Watts' advice and we “stood there” and looked at it along time. Then we tested the socket off of the patient. We were using the Otto Bock flexible plastic socket attachment elbow to attach the vacuum tube to the socket as per instructions. For testing purposes, we attached a hose to the plastic elbow and put a gauge on the hose and a hand pump. Then we sealed the top of the socket with the gel end pad that comes with the OWW troubleshooting kit. We pumped up the socket and found that we could not pump it up above 20" Hg. And then it quickly lost vacuum. We then exchanged the plastic elbow for the older metal type that threads into the socket. It sealed perfectly and we tested it again. This time the valve and tube were sealed perfectly. We continued to test the rest of the system and found that the sleeve also was leaking. It had appeared perfect, but indeed it had some pinholes. We replaced the sleeve with a new sleeve and continued to test. Finally the system was sealed and we gave it back to the patient. She then quite liked the Harmony system.
The lesson: Don’t assume anything; don’t rush to blame components or patient preference. If it leaks it leaks. Make no conclusions about components or socket design until the system is holding a vacuum without leaking.