Clinical FAQs
Which side of the scanner should I work from?
As you are facing the machine you should be on the right side of the scanning unit. The right hand always controls the big toe pressure while the left is pushing buttons and adjusting the pressure slider. If you position yourself on the left side you will be reaching between the patients legs and will find your head directly under someone's dark side. ;-)
How do I know if I've done a good scan?
If you've followed all scanning tips dealing with foot centering, pin pressure, toe plate placement and the application of slight pressure on the big toe you are well on your way. Look for symmetry and both sides of the heel cup being the same height ( check View 2-D and "elevation legend").
It's OK to have a slightly higher medial heel cup– since 85% of us are pronators this will transfer into more support in this area.
Arch support begins in the heel and ends in the forefoot. Smooth transitions from one to the other will result in a good insert. Look for smoothness in the 2-D colors--not choppiness or unevenness.
The single biggest problem is over posting of the first met head. This is why slight pressure on the big toe during the "pins up" AND "lock" mode is extremely important. Pressure on the big toe allows just the right amount of posting under the first. Be sure the patient does not move the foot once you have positioned it. Forefoot positioning is very important and requires constant monitoring by the practitioner– tip– (if a bunion is involved disregard it– do not use it as an alignment edge). The patient will generally shift their feet. Remember this is the first time they are on the scanner and not sure what to do--you must tell them.
Don't be satisfied with the first scan– Scan as much as you want and then talk to someone who has more experience and review them. Many new users are nervous about scanning more than once for fear of showing the patient they didn't get it right on the first attempt– there is nothing further from the truth. The best scanners scan 2-4 times and use the best scan. This is the beauty of an electronic casting device. More scans are quick, effective and free. Save the ones you want and delete the rest.
When I scan the 2-D & 3-D image of the heel is way off center even though
the impression in the pins looks centered?
This will happen on occasion and it is an easy fix. First check the heel area of the foot impression still locked in the pins. Be sure the heel was centered in the pins to begin with. Then go back to the digitize window and deselect "Auto Heel Centering". Then click scan. This will rescan the same
foot impression but not try to "Auto" center it for you. When finished be sure to reselect "Auto Heel Centering" for the next foot– yes it does work most of the time.
How do I get better heel cupping and or arch support while scanning?
Place the foot on the scanner and hit pins up. Wait the desired 12 seconds so the pins have risen to their full height. Help the patient lift the heel 3/4" off the scanner--be sure to keep the heel centered and lift for only 3 seconds– then reseat the heel in the pins. If you get a choppy look in the heel cup after scanning you are lifting too high or the pin pressure is too great. Try again. Remember a good scan looks symmetrical in all areas of the 2-D image. You will indeed gain more arch support as well as heel cupping from this process.
What is the best way to scan a foot?
Use the Semi-weight bearing approach--(one foot on the scanner and one foot off). Always keep slight pressure on the big toe to prevent over posting of the first metatarsal. Center the heel in the heel guide being sure to keep slight contact between the two. Control pins up pressure with the slider on the front of the scanner.(more on pin pressure below).
How do I center the forefoot?
Keep the same number of pin rows on both the medial and lateral sides of the forefoot. If there is a bunion involved disregard it. Do not use the bunion edge as an alignment edge this will throw the forefoot off to one side. Some practitioners draw a pen line where the edge of the foot would
be if the bunion were not present. Some users were taught to keep the center line on the toe plate between the second and third toes for forefoot centering. This works for certain foot configurations but not all. Using the first method works for everyone.
Toe plate positioning?
Really depends on the amount of sulcus you desire. Best method for minimal sulcus is to slide the toe plate back till it contacts the ball of the foot then forward about 1/8". Never slide the toe plate completely under the ball of the foot(under the met heads).
If more sulcus is desired simply slide the plate further forward. You can use software adjustments to increase or decrease sulcus but there are blending issues involved--simpler is always better--use the toeplate.
What about Pin pressure?
This is a big one. Pin pressure is one of the most important tools to master on the scanner. Rule of thumb: IN THE SEMI WEIGHTED POSITION, Men weighing between 170-220 lbs set pin pressure just slightly under the 1/2 lb mark (the half moon icon). Women weighing between 100-130 lbs set pin pressure to just over the 1/4 lb mark (the quarter moon icon).
For big guys over 250 lbs you may want to go between 1/2 to 3/4 lb of pressure.
Generally, we never go over 3/4 lb for anyone. It is very easy to lift a patient off the scanning plate using pin pressure. The idea is to support fully while not over supporting.
