Repair of pectus excavatum (sunken Chest) currently involves a major surgical repair accompanied by a 3-7 day post-operative hospital stay and outpatient treatment with prescription pain medication. We have created the Magnetic Mini-Mover System which utilizes magnetic force to reconfigure the patient's abnormal chest. The implanted magnet is placed during a 30-60 minute outpatient procedure and the patient usually goes home the same day on over-the-counter pain medication. The Magnetic Mini Mover System was most effective in treating the Pectus deformity in pre-pubertal patients but less effective in older teens with more rigid chest walls, so in the second trial we treated only pre pubertal patients. The device has been trialed in 25 patients where the concept works, but the means to anchor the implant to the sternum has proven problematic. The Magnetic Mimi Mover Device, currently consists of a neodymium iron boron disc magnet, (1.5 cm diameter x 3/16 in. thick) and a ferromagnetic focusing plate encased in a low-profile titanium shell. It is held in place on the sternum using woven titanium cables and a titanium backing plate. The cable is titanium alloy (Ti-6Al-4V ELI) of 7 wire strands wrapped into a cable then 7 cables each 0.0065? are wrapped together to given a woven cable of 0.05940? and 15.875? in length. This configuration was developed for commercially available orthopedic titanium cables. The external custom brace houses another rare- earth magnet that can be adjusted using a plastic housing built into the orthotic brace. Adjustments in the magnets distances will slowly pull the chest out over 24-36 months in a process similar to that used in orthodontics. The device is patented (US 8043290) and we are filing for modifications to the new design as well as the external brace. It has also and has obtained a Humanitarian Use Designation (08- 0200) from the FDA. We have completed our 1st clinical trial and in the midst of a 2nd multi- centered funded by the Office of Orphan Products at the FDA. In both trials we have had a difficulty designing the internal magnet, specifically attaching it to the sternum and developing a universal shape for both symmetrical and asymmetrical sternums. However the chest repairs were successful due to the encapsulation of the device on sternum. We are requesting funds to modify the design of the implanted magnet housing and the means of attaching it to the sternum. This will be the third and potentially the last design iteration before commercialization. During the last trial we learned the importance of including the effects of patient respirations as a test to determine the strength and viability of the implant. This study will evaluate and create: 1. A means to quantify the effects of patient respirations on the design of the new device 2. A locking mechanism on the implant that will best remain immovableof implant will best remain immovable on the sternum 3. A mechanism that will not injure the bone and cartilage on the sternum, 4. A mechanism fit best onto the bone disorder most noticeable on the sternum during the course of the two year trial.
The Magnetic Mini Mover Device for the treatment of petcus excavatum (PE) has undergone two clinical trials. Our device is composed of two neodymium magnets. One is encased in titanium and affixed to the patient's sternum during a 1 hour operation. The second is attached to an orthotic brace that is held in place by the attraction of the two magnets. Over the course of a two year treatment the chestwall is moved back into a near normal position. We have shown that the device is beneficial to a specific group of PE patients, usually those between the ages of 8 and 14 who have not gone through their pubertal spirt yet. During both trials the mechanism (screw then cables) that affixed the internal to the sternum broke. During the second trial the magnet became encased on the patient's chest and the cable breakage did not affect the completion of the trial. In face the patients' chests continued to improve even though the cables holding it in place did not break. It turned out that patient respirations over about 16,000,000 in two years, were responsible for the cable damage in trial two. The FDA is requesting a third patient study to show that a new device would be considered safe during the entire trial. We will be developing a third no-cost trial with the Shriners Hospital system. We are developing a new implant that uses neither a screw nor a cable to hold in in place on the sternum. Three dimensional modeling and a library of CT scans from our two trails are being used to help create a simpler stronger implant. These tools and the participation of orthopedic researchers, skilled in bone remodeling are helping us to better understand the stresses associated with respiratory movement during the trial. We believe that this third design will overcome the issues experienced in our earlier trials and more the device closer to commercialization.
