The Novel Use of Rare Earth Magnets for the Extraction of Metallic Soft Tissue Foreign Bodies in Children.

INTRODUCTION: Metallic foreign bodies (mFB) are common following penetrating injuries in children. The mFB commonly occur in the head and neck region and extremity soft tissues. Removal may be indicated due to morbidity related to pain or migration. Extraction can be challenging to localize, often requiring wide exposure, and may be difficult to achieve in cosmetically sensitive areas. Different technological adjuncts have been used to facilitate foreign body removal including fluoroscopy, ultrasound, and more recently in adults, surgical magnets. The most powerful commercially available magnets are rare earth magnets comprised of neodymium iron and boron (Ndy). With the goal of reducing radiation exposure and the morbidity of mFB removal with associated soft tissue injury in children, a strategy was introduced utilizing Ndy to optimize extraction with minimal soft tissue surgical dissection.

MATERIALS AND METHODS: Two children with extremity mFB treated with Ndy between January 2021 and July 2021 were analyzed. We utilized commercially available ring type neodymium-iron-boron magnets with dimensions of 1 3/8-inch outer diameter x 1/8-inch inner diameter and 1/16 inch thick with a power of 13 200 gauss that were processed for use according to our hospital protocols. Our main clinical indication was for the detection and retrieval of small ferromagnetic foreign bodies embedded in superficial extremity soft tissues.

RESULTS: In the operating room under general anesthesia, the mFB were localized utilizing fluoroscopy. A 1.0 cm skin incision was made into the subdermal soft tissues overlying the area of the mFB. No surgical tissue dissection was performed. The mFB could not be visualized in the soft tissue. Using fluoroscopy to localize the mFB, the Ndy was then placed into the wound in close proximity to the mFB. The mFB were immediately magnetized to the Ndy and the mFB were extracted from the soft tissues without any further surgical dissection. Two simple interrupted nylon sutures were placed to close the incision. The total operative time was 2 and 2.5 minutes respectively. The children recovered uneventfully and are without complication.

CONCLUSIONS: The use of Ndy to remove extremity soft tissue mFB in children appears to be feasible, safe, and efficient. Use of the Ndy allowed extraction via a small incision, optimizing the aesthetic result and avoiding the need for cross-sectional imaging, extensive surgical dissection, tissue reconstruction and prolonged operative time or x-ray exposure. The development of magnets of increasing energy density may be indicated to further optimize metallic soft tissue foreign body extraction in children in a minimally invasive manner.