Magnetic Mini-Mover Procedure to Treat Pectus Excavatum

Phase 1

Completed

Conditions: Pectus Excavatum

Interventions: Device: Magnetic Mini-Mover Procedure (3MP)
Device: Magnatract (external magnet in a removable external brace)
Procedure: 3MP (Magnetic Mini-Mover Procedure)

Registration Number: NCT00466206

Lead Sponsor: University of California, San Francisco

Brief 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.

Recruitment & Eligibility

Status: COMPLETED

Sex: All

Target Recruitment: 10

Inclusion Criteria

Resident of the U.S.;
Otherwise healthy male or female with pectus excavatum deformity;
Between 8 and 14 years of age;
Pectus Severity Index > 3.5 (normal 2.56); and
Ability to read and speak English.

Exclusion Criteria

Other congenital anomalies (including significant skeletal anomalies such as scoliosis, bony fusion involving the cervical vertebrae) not directly related to pectus excavatum;
Bleeding disorders;
Heart disease (including arrhythmia);
Persons with active implantable medical devices (AIMD) such as pacemakers;
Persons with a relative(s) or close family friend(s) living within their households and having a pacemaker;
Persons with arteriovenous malformations;
Chest deformity more complicated than pectus excavatum (e.g.. Poland syndrome);
Persons for whom a foreign body implant would pose a risk (e.g., immunodeficiency);
Persons at increased risk for general anesthesia (e.g., history of malignant hyperthermia);
Respiratory conditions that have required steroid treatment (e.g., prednisone)in the last 3 years;
Pregnancy;
Inability to understand or follow instructions;
Refusal to wear the external brace;
Inability to obtain pre-approval (authorization) from the patient's insurance carrier; and
Inability or refusal to return to UCSF for weekly follow-up visits for the first month after surgery.

Study & Design

Study Type: INTERVENTIONAL

Study Design: SINGLE_GROUP

Arm && Interventions

Group	Intervention	Description
3MP - Treatment Arm	Magnetic Mini-Mover Procedure (3MP)	Magnetic Mini-Mover Procedure using the Magnimplant and Magnatract
3MP - Treatment Arm	Magnatract (external magnet in a removable external brace)	Magnetic Mini-Mover Procedure using the Magnimplant and Magnatract
3MP - Treatment Arm	3MP (Magnetic Mini-Mover Procedure)	Magnetic Mini-Mover Procedure using the Magnimplant and Magnatract

Primary Outcome Measures

Name	Time	Method
Affect on Cardiac Activity	One month post-explantation	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	One-month post-explant	Outcome measure is number of patients who experienced permanent skin damage or discoloration due to external brace wear
Efficacy: Patient Satisfaction	One year post-explant	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	One year post-explanation	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

Secondary Outcome Measures

Name	Time	Method
Patient Compliance	18 months active Rx	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