Magnetic Mini-Mover Procedure to Treat Pectus Excavatum (3MP)
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.
Device: Magnetic Mini-Mover Procedure (3MP)
Device: Magnatract (external magnet in a removable external brace)
Procedure: 3MP (Magnetic Mini-Mover Procedure)
|Study Design:||Endpoint Classification: Safety/Efficacy Study
Intervention Model: Single Group Assignment
Masking: Open Label
Primary Purpose: Treatment
|Official Title:||Phase II Magnetic Alteration of Pectus Excavatum|
- Affect on Cardiac Activity [ Time Frame: One month post-explantation ] [ Designated as safety issue: Yes ]EKG performed prior to implantation, one month post-implantation, and after explanation to evaluate whether magnetic field near the heart adversely affects cardiac activity. Outcome measure describes number of patients who experienced adverse change in EKG.
- Damage/Discoloration to Skin [ Time Frame: One-month post-explant ] [ Designated as safety issue: Yes ]Outcome measure is number of patients who experienced permanent skin damage or discoloration due to external brace wear
- Efficacy: Patient Satisfaction [ Time Frame: One year post-explant ] [ Designated as safety issue: No ]Based on patient response to one-year post-explantation QoL questionnaire: How satisfied are you with the correction of your chest? Ratings: 5-very satisfied; 4-satisfied; 3-unsure; 2-dissatisfied; 1-very dissatisfied
- Efficacy: Patient Recommendation of Treatment [ Time Frame: One year post-explanation ] [ Designated as safety issue: No ]Based on patient response to one-year post-explantation QoL statement: "I would recommend this treatment for pectus excavatum (sunken chest) to someone else with pectus excavatum." Ratings: 5-strongly agree; 4-agree; 3-unsure; 2-disagree; 1-strongly disagree
- Patient Compliance [ Time Frame: 18 months active Rx ] [ Designated as safety issue: No ]Compliance measured by average number of hours per day external device was worn by patient, as measured by the data sensor and logging device built into external prosthetic
|Study Start Date:||April 2007|
|Study Completion Date:||April 2011|
|Primary Completion Date:||May 2010 (Final data collection date for primary outcome measure)|
Experimental: 3MP - Treatment Arm
Magnetic Mini-Mover Procedure using the Magnimplant and Magnatract
Device: Magnetic Mini-Mover Procedure (3MP)
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.
Other Name: 3MPDevice: Magnatract (external magnet in a removable external brace)
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.
Other Name: Magnetic Mini-moverProcedure: 3MP (Magnetic Mini-Mover Procedure)
Other Name: 3MP
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.
Please refer to this study by its ClinicalTrials.gov identifier: NCT00466206
|United States, California|
|University of California, San Francisco|
|San Francisco, California, United States, 94143-0570|
|Principal Investigator:||Michael R Harrison, MD||University of California, San Francisco Medical Center and Children's Hospital|