Magnetic Mini-Mover Procedure to Treat Pectus Excavatum

Pectus Excavatum Clinical Trial

— 3MP  

Official title:

Phase II Magnetic Alteration of Pectus Excavatum

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT00466206
• Other study ID #: FD 003341
• Status: Completed
• Phase: Phase 1/Phase 2
• First received: April 24, 2007
• Last updated: December 2, 2015
• Start date: April 2007
• Est. completion date: April 2011

Study information

• Verified date: December 2015
• Source: University of California, San Francisco
• Contact: n/a
• Is FDA regulated: No
• Health authority: United States: Food and Drug Administration
• Study type: Interventional

Clinical Trial 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.

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 information / eligibility

• Status: Completed
• Enrollment: 10
• Est. completion date: April 2011
• Est. primary completion date: May 2010
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: Both
• Age group: 8 Years to 14 Years

Eligibility

Residents of the United States with previously diagnosed pectus excavatum who are referred to the UCSF Pediatric Surgery Service for evaluation and treatment will be considered for participation in this study. Only patients with moderate to severe pectus excavatum who meet all the inclusion criteria will participate. The patient and family will be fully counseled and consented about the risks and benefits of participation in the study, and will be asked to sign an informed consent reviewed and approved by the UCSF Committee on Human Research.

Inclusion Criteria:

1. Resident of the U.S.;

2. Otherwise healthy male or female with pectus excavatum deformity;

3. Between 8 and 14 years of age;

4. Pectus Severity Index > 3.5 (normal 2.56); and

5. Ability to read and speak English.

Exclusion Criteria:

1. Other congenital anomalies (including significant skeletal anomalies such as scoliosis, bony fusion involving the cervical vertebrae) not directly related to pectus excavatum;

2. Bleeding disorders;

3. Heart disease (including arrhythmia);

4. Persons with active implantable medical devices (AIMD) such as pacemakers;

5. Persons with a relative(s) or close family friend(s) living within their households and having a pacemaker;

6. Persons with arteriovenous malformations;

7. Chest deformity more complicated than pectus excavatum (e.g.. Poland syndrome);

8. Persons for whom a foreign body implant would pose a risk (e.g., immunodeficiency);

9. Persons at increased risk for general anesthesia (e.g., history of malignant hyperthermia);

10. Respiratory conditions that have required steroid treatment (e.g., prednisone)in the last 3 years;

11. Pregnancy;

12. Inability to understand or follow instructions;

13. Refusal to wear the external brace;

14. Inability to obtain pre-approval (authorization) from the patient's insurance carrier; and

15. Inability or refusal to return to UCSF for weekly follow-up visits for the first month after surgery.

Study Design

Endpoint Classification: Safety/Efficacy Study, Intervention Model: Single Group Assignment, Masking: Open Label, Primary Purpose: Treatment

Related Conditions & MeSH terms

• Funnel Chest
• Pectus Excavatum

Intervention

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.
• 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.

Procedure:
• 3MP (Magnetic Mini-Mover Procedure)
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.

Locations

Country	Name	City	State
United States	University of California, San Francisco	San Francisco	California

Sponsors (2)

Lead Sponsor	Collaborator
University of California, San Francisco	FDA Office of Orphan Products Development

Country where clinical trial is conducted

United States, 

References & Publications (19)

ADKINS PC, BLADES B. A stainless steel strut for correction of pectus escavatum. Surg Gynecol Obstet. 1961 Jul;113:111-3. — View Citation

Beiser GD, Epstein SE, Stampfer M, Goldstein RE, Noland SP, Levitsky S. Impairment of cardiac function in patients with pectus excavatum, with improvement after operative correction. N Engl J Med. 1972 Aug 10;287(6):267-72. — View Citation

Fonkalsrud EW, Reemtsen B. Force required to elevate the sternum of pectus excavatum patients. J Am Coll Surg. 2002 Oct;195(4):575-7. — View Citation

Haller JA Jr, Loughlin GM. Cardiorespiratory function is significantly improved following corrective surgery for severe pectus excavatum. Proposed treatment guidelines. J Cardiovasc Surg (Torino). 2000 Feb;41(1):125-30. — View Citation

Hebra A, Swoveland B, Egbert M, Tagge EP, Georgeson K, Othersen HB Jr, Nuss D. Outcome analysis of minimally invasive repair of pectus excavatum: review of 251 cases. J Pediatr Surg. 2000 Feb;35(2):252-7; discussion 257-8. — View Citation

Kowalewski J, Barcikowski S, Brocki M. Cardiorespiratory function before and after operation for pectus excavatum: medium-term results. Eur J Cardiothorac Surg. 1998 Mar;13(3):275-9. — View Citation

Lawson ML, Cash TF, Akers R, Vasser E, Burke B, Tabangin M, Welch C, Croitoru DP, Goretsky MJ, Nuss D, Kelly RE Jr. A pilot study of the impact of surgical repair on disease-specific quality of life among patients with pectus excavatum. J Pediatr Surg. 2003 Jun;38(6):916-8. — View Citation

Malek MH, Fonkalsrud EW, Cooper CB. Ventilatory and cardiovascular responses to exercise in patients with pectus excavatum. Chest. 2003 Sep;124(3):870-82. — View Citation

Mead J, Sly P, Le Souef P, Hibbert M, Phelan P. Rib cage mobility in pectus excavatum. Am Rev Respir Dis. 1985 Dec;132(6):1223-8. — View Citation

Morshuis WJ, Mulder H, Wapperom G, Folgering HT, Assman M, Cox AL, van Lier HJ, Vincent JG, Lacquet LK. Pectus excavatum. A clinical study with long-term postoperative follow-up. Eur J Cardiothorac Surg. 1992;6(6):318-28; discussion 328-9. Review. — View Citation

Nuss D, Croitoru DP, Kelly RE Jr, Goretsky MJ, Nuss KJ, Gustin TS. Review and discussion of the complications of minimally invasive pectus excavatum repair. Eur J Pediatr Surg. 2002 Aug;12(4):230-4. — View Citation

Park HJ, Lee SY, Lee CS. Complications associated with the Nuss procedure: analysis of risk factors and suggested measures for prevention of complications. J Pediatr Surg. 2004 Mar;39(3):391-5; discussion 391-5. — View Citation

RAVITCH MM. The operative treatment of pectus excavatum. J Pediatr. 1956 Apr;48(4):465-72. — View Citation

Shamberger RC. Cardiopulmonary effects of anterior chest wall deformities. Chest Surg Clin N Am. 2000 May;10(2):245-52, v-vi. Review. — View Citation

Shamberger RC. Congenital chest wall deformities. Curr Probl Surg. 1996 Jun;33(6):469-542. Review. — View Citation

Weber TR. Further experience with the operative management of asphyxiating thoracic dystrophy after pectus repair. J Pediatr Surg. 2005 Jan;40(1):170-3. — View Citation

WELCH KJ. Satisfactory surgical correction of pectus excavatum deformity in childhood; a limited opportunity. J Thorac Surg. 1958 Nov;36(5):697-713. — View Citation

Wynn SR, Driscoll DJ, Ostrom NK, Staats BA, O'Connell EJ, Mottram CD, Telander RL. Exercise cardiorespiratory function in adolescents with pectus excavatum. Observations before and after operation. J Thorac Cardiovasc Surg. 1990 Jan;99(1):41-7. — View Citation

Zhao L, Feinberg MS, Gaides M, Ben-Dov I. Why is exercise capacity reduced in subjects with pectus excavatum? J Pediatr. 2000 Feb;136(2):163-7. — View Citation

* Note: There are 19 references in all — Click here to view all references

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Affect on Cardiac Activity	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.	One month post-explantation	Yes
Primary	Damage/Discoloration to Skin	Outcome measure is number of patients who experienced permanent skin damage or discoloration due to external brace wear	One-month post-explant	Yes
Primary	Efficacy: Patient Satisfaction	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	One year post-explant	No
Primary	Efficacy: Patient Recommendation of Treatment	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	One year post-explanation	No
Secondary	Patient Compliance	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	18 months active Rx	No