Claire E Graves1, Shinjiro Hirose2, Gary W Raff2, Corey W Iqbal3, Jill Imamura-Ching1, Darrell Christensen4, Richard Fechter1, Dillon Kwiat1, Michael R Harrison5. 1. Division of Pediatric Surgery, UCSF Benioff Children's Hospital, 550 16th Street, 5th Floor, Box 0570, San Francisco, CA 94143, United States. 2. Davis Health System, Department of Surgery, University of California, 2315 Stockton Blvd., OP512, Sacramento, CA 95817, United States; Department of Surgery, Shriners Hospital for Children-Northern California, 2425 Stockton Blvd., Sacramento, CA 95817, United States. 3. Department of Surgery, Children's Mercy Hospital, 2401 Gillham Rd., Kansas City, MO 64108, United States. 4. Department of Orthopaedic Surgery, UCSF Medical Center, 400 Parnassus Ave, Level B1, Room A096, San Francisco, CA 94143, United States. 5. Division of Pediatric Surgery, UCSF Benioff Children's Hospital, 550 16th Street, 5th Floor, Box 0570, San Francisco, CA 94143, United States. Electronic address: Michael.harrison@ucsf.edu.
Abstract
PURPOSE: The Magnetic Mini-Mover Procedure (3MP) is a minimally invasive treatment for prepubertal patients with pectus excavatum. This multicenter trial sought to supplement safety and efficacy data from an earlier pilot trial. METHODS: Fifteen patients with pectus excavatum had a titanium-enclosed magnet implanted on the sternum. Externally, patients wore a custom-fitted magnetic brace. Patients were monitored closely for safety. Efficacy was determined by the Haller Index (HI) and satisfaction surveys. After 2 years, the implant was removed. RESULTS: Mean patient age was 12 years (range 8-14), and mean pretreatment HI was 4.7 (range 3.6-7.4). The device was successfully implanted in all patients. Mean treatment duration was 25 months (range 18-33). Posttreatment chest imaging in 13 patients indicated that HI decreased in 5, remained stable in 2, and increased in 6. Seven out of 15 patients had breakage of the implant's titanium cables because of fatigue fracture. Eight out of 13 patients were satisfied with their chest after treatment. CONCLUSION: The 3MP is a safe, minimally invasive, outpatient treatment for prepubertal patients with pectus excavatum. However, the magnetic implant design led to frequent device breakage, confounding analysis. The HI indicated mixed efficacy, although surveys indicated most patients perceived a benefit. STUDY TYPE/LEVEL OF EVIDENCE: Case series, treatment study. Level IV.
PURPOSE: The Magnetic Mini-Mover Procedure (3MP) is a minimally invasive treatment for prepubertal patients with pectus excavatum. This multicenter trial sought to supplement safety and efficacy data from an earlier pilot trial. METHODS: Fifteen patients with pectus excavatum had a titanium-enclosed magnet implanted on the sternum. Externally, patients wore a custom-fitted magnetic brace. Patients were monitored closely for safety. Efficacy was determined by the Haller Index (HI) and satisfaction surveys. After 2 years, the implant was removed. RESULTS: Mean patient age was 12 years (range 8-14), and mean pretreatment HI was 4.7 (range 3.6-7.4). The device was successfully implanted in all patients. Mean treatment duration was 25 months (range 18-33). Posttreatment chest imaging in 13 patients indicated that HI decreased in 5, remained stable in 2, and increased in 6. Seven out of 15 patients had breakage of the implant's titanium cables because of fatigue fracture. Eight out of 13 patients were satisfied with their chest after treatment. CONCLUSION: The 3MP is a safe, minimally invasive, outpatient treatment for prepubertal patients with pectus excavatum. However, the magnetic implant design led to frequent device breakage, confounding analysis. The HI indicated mixed efficacy, although surveys indicated most patients perceived a benefit. STUDY TYPE/LEVEL OF EVIDENCE: Case series, treatment study. Level IV.