Magnetic Mini-Mover Procedure to Treat Pectus Excavatum
Condition: Pectus Excavatum
MeSH terms: Funnel Chest
Study type: Interventional
Phase: Phase 1/Phase 2

Summary: 
      This is a medical research study.

      The study investigators have developed a method to gradually repair pectus excavatum (sunken
      chest) deformity by placing a magnet on the sternum (breastbone) and then applying an
      external magnetic force that will pull the sternum outward gradually.

      Potential candidates for this study are children and adolescents with a previously diagnosed
      congenital pectus excavatum (sunken chest) deformity who are otherwise healthy and are
      seeking corrective surgery for their condition. They will be residents of the U.S. and
      between the ages of 8 and 14 years of age. Potential candidates and their families will have
      already been counseled about this condition and about the standard way to repair this
      deformity.

      The purpose of this study is to test what effects, good and/or bad, placing an
      external/internal magnetic device has on correcting pectus excavatum deformity in children,
      and the safety of using such a device for treatment.
    

Detailed description: 
      Pectus excavatum is the most common congenital chest wall abnormality in children. Surgical
      correction requires a big operation under general anesthesia which forces the sternum forward
      and holds it in place using a metal chest wall strut. Deformation of the chest wall under
      great pressure may result in complications and potential relapses as well as postoperative
      pain requiring hospitalization for regional and narcotic anesthesia for up to a week. An
      alternative principle for correction of chest wall and other deformities is gradual
      (bit-by-bit) correction using minimal force applied over many months (like moving teeth with
      orthodontic braces).

      The hypothesis of this study is that constant outward force on the deformed cartilage in
      pectus excavatum will produce biologic reformation of cartilage and correction of the chest
      wall deformity.

      The study investigators have developed a novel method of achieving gradual
      deformation/reformation of chest wall cartilage without the need for transdermal orthopedic
      devices or repeated surgeries. A magnetic force field is used to apply controlled, sustained
      force to promote biologic reformation of structural cartilage (the same principle as
      distraction osteogenesis). A magnet is implanted on the sternum and secured using a novel
      fixation strategy that can be accomplished through a 3-cm subxyphoid incision as a brief
      outpatient procedure. The magnet (and sternum) is pulled outward by another magnet suspended
      in a novel, low-profile, lightweight device previously molded to the patient's anterior chest
      wall. The external magnet allows individual adjustment in small increments of the distance
      (and, thus, force) and orientation of the force applied to the sternum. The low-profile,
      non-obtrusive anterior chest wall prosthesis is held in place by the force field between the
      two magnets.

      The study objectives are to test the safety and probable benefit of this procedure in 10
      otherwise healthy, young patients, between 8 years and 14 years of age, who have chosen to
      have this deformity corrected using this novel technique rather than the standard Ravitch or
      Nuss techniques. We will document the rate of correction by chest imaging and measurement of
      the Pectus Severity Index. The study investigators will document safety and efficacy with an
      EKG prior to implantation, one month post-implantation, and finally after the magnet is
      removed, as well as patient and family satisfaction with a post-procedure Quality of
      Life-type survey.
    

Intervention name(s): Magnetic Mini-Mover Procedure (3MP); Magnatract (external magnet in a removable external brace); 3MP (Magnetic Mini-Mover Procedure)
Intervention type(s): Device; Device; Procedure
Intervention description(s): A rare earth magnet encased in FDA-approved titanium will be implanted securely on the outer surface of the lower end of the sternum in patients with pectus excavatum. This is accomplished as an outpatient procedure, under brief general anesthesia.
A 2-inch transverse skinline incision is made at the junction of the sternum and xyphoid and the space in front and behind the sternum is dissected bluntly. The titanium can containing the magnet is securely fixed to the sternum by screwing it into a titanium fixation disk in front of the sternum. The procedure takes 1/2-hour, and the patient can go home the same day.
In another outpatient procedure, the Magnimplant is explanted 18 months after implantation.; An external orthotic device "Magnatract" which includes an external magnet in a removable brace is fitted specifically to the patient's chest wall deformity. A calibrated meter in the external device measures the force applied between the two magnets. When the patient and family are comfortable with the device and comfort and skin condition have been assessed, the patient will be allowed to take the Magnatract home and begin the process of gradually advancing the sternum forward as the abnormal costal cartilage is reformed.; Subject has EKG performed to measure baseline cardiac activity.
Magnimplant is implanted.
After one week, "Magnatract" is fitted.
Chest x-ray and 2nd EKG performed 30 days post-implantation.
Patient and parents complete QoL questionnaire 30d post-implantation.
Patient seen weekly for first month post-implantation to assess comfort and skin condition. Thereafter, will be seen monthly.
At each monthly visit, patient will have lateral and anterior-posterior chest X-rays to monitor sternal correction.
At each visit data logger is downloaded to measure strength of pull since last visit and amount of wear-time.
Magnimplant explanted 18 months later as 1/2-hr outpatient procedure.
CT scan and third EKG performed after explanation.
Patient and parents complete QOL questionnaires after explantation and 1 yr post-explantation.
Other intervention name(s): 3MP; Magnetic Mini-mover; 3MP
Intervention model: Single Group Assignment
Masking: None (Open Label)
Primary purpose: Treatment
Keywords: pectus excavatum; magnetic alteration; chest wall deformity