sonographic evaluation of magec growing scoliosis rods in pediatric patients cincinnati children’s...

Sonographic Evaluation of MAGEC Growing Scoliosis Rods

in Pediatric Patients

Cincinnati Children’s Hospital Medical Center

Department of Orthopaedics Department of Radiology

Peter Sturm, MDSara M. O’Hara, MD

Lindsay Schultz, BS,CCRP

Disclosures

• Peter Sturm, MD- Consultant for Medtronic

Consultant for Ellipse• Sara M. O’Hara, MD- Speakers bureau Toshiba

Medical Ultrasound• Lindsay Schultz, BS,CCRP - NONE

Purpose•Adjustable, magnetically controlled “growing” scoliosis rods (MAGEC rods) are increasingly used in pediatric patients, and require periodic adjustments and confirmation of lengthening following this non-invasive procedure.

•Previously, adjustable rods required open surgical procedures for lengthening. The purpose of our study was to determine if these MAGEC rods could be adequately visualized and measured with ultrasound, thereby minimizing radiation exposure from serial spine X-rays.

Motor and housing

Expandable rod housing

Expanded segment

MAGEC ROD

Motor

Rod housingExtended segment of rod

Segment we measure

MAGEC ROD

Materials & Methods• All patients with recently implanted MAGEC rods were examined with

ultrasound before and after their first transcutaneous magnetic rod lengthening procedures. Measurements obtained sonographically were compared with the length programmed into the magnetic motor used to extend the rod. Measurements will also be compared with scoliosis X-rays obtained once or twice each year.

Ortho localizes the motor with magnetic wand (blue)or with ultrasound, and marks site(s),

Sets the motor driver parameters, then activates on patient

Motor is audible, stops automatically, not painful!

Ultrasound can readily identify: Gap between housing and extended rod and tapered end of rod

We measure and report distance between gap and TOP of slope, pre & post lengthening

Results• 12 patients have been studied to this point (3 month period)

• 6 female, and 6 male, between 6 and 10 years of age

• All of the MAGEC rods were well visualized sonographically

before and after lengthening procedure.

• All of the patients showed good correlation between post-op

scoliosis measurements and first, pre-lengthening ultrasound

measurements.

• 4 of the 13 patients rods showed less lengthening than expected

based on the length programmed into the magnetic motor driver.

• All patients will be re-imaged in the next few months to quantify

measurement reliability and compare with

expected extension parameters.

ConclusionMAGEC rods can be reliably imaged with ultrasound before and after transcutaneous lengthening procedures, thereby reducing radiation exposure.

In addition, the ultrasound may offer additional confidence that the rods have in fact extended the length programmed into the magnetic motor.