This is Part 2 of a series on Stella’s head. Part 1 is here.
We had an appointment Hanger Prosthetics. We had a lot of questions and were rather apprehensive about the doing this as the kids pediatrician really wasn’t very knowledgeable about the subject.
One of the first things that Julia, our assigned Orthotist, did was to get a large pair of calipers and measure the asymmetry of Stella’s head. Two measurements were taken in an X orientation from from each temple to the oposing back-side of the head. The result was 13 mm difference, which was well above the threshold of “medical relevence” (8 mm, IIRC). It wasn’t the worst she’d seen which was in the high teens.
The “good” news was that the severity was sufficient that insurance would pick up the bill. And, the bill was not cheep — list price for the whole procedure was about $2500! Regardless, we had committed to it and would have paid out of pocket if it came down to it. We made the commitment and proceeded to the next step: scanning her head.
The scanning process uses an laser scanner to map the precise shape and size of Stella’s head in order to build the custom helmet.
First, they put on a “sock” over her head. This served 2 purposes: kept the hair from showing up in the scan, and it allowed the positional reference transmitter/sensor to be affixed to her head without sticking in her hair.
iPhone, map
Then they affixed the sensor gizmo which lets the scanner know where it is scanning relative to Stella’s head movement.
iPhone, map
Then they darkened the room and scanned her head from top to bottom using about 10 swipes to get all the way around.
iPhone, map
Below is a screen shot of what the scan looks like after they applied a smoothing algorithm to remove the small bumps. I missed the shot, but, prior to the smoothing, the raw scanner output was a very precise rendering of Stella’s face with her little dimples and details of the hook and loop layers used to hold the sensor gizmo to her head.
iPhone, map
The blue lines scan are reference lines for where the top of her forehead is and an outline of where the ear holes need to be cut out.
And that was it. Quick and easy, well, other than trying to get a baby to hold her head still!
About 2 weeks later, the new helmet was ready.