Magnetic resonance imaging assessment of a microvascular anastomotic device for ferromagnetism

Microvascular free-tissue transfers have assumed particular importance as reconstructive techniques of choice in centers where ablative surgery for primary and recurrent malignant disease is a focus. In the context of malignant disease, issues of surveillance for recurrence are paramount. As clinical experience with the diagnostic imaging characteristics of flap reconstructions has been acquired, magnetic resonance imaging (MRI) has assumed a prominent role in the evaluation for recurrent malignant disease. This has provided an important supportive role for contemporary concepts of immediate reconstruction. The Precise-TM Microvascular Anastomotic Device (MACD) is based on the friction-fit union of implant rings composed of high-density polyethylene and surgical stainless steel. Many characteristics of the device have been described in histologic and laboratory studies. As yet uncharacterized is the effect of clinical MRI electromagnetic fields on the device, which is composed, in part, of type 316 stainless steel. The MACD is in wide use in centers where microsurgeons are experienced with the system and it is designed to facilitate the performance and reliability of microvascular anastomoses. The implications for MRI as a safe imaging modality for the acute perioperative evaluation of patients reconstructed with microvascular free flaps anastomosed with the MACD are obvious. MACD implants of varying sizes were evaluated for displacement in each of three orthogonal planes within a 1.5 Tesla magnetic field. No change in displacement was observed for any of the devices. Magnetic resonance imaging may thus be considered a safe imaging modality for the acute perioperative diagnostic imaging of free-tissue transfers that have been anastomosed with the MACD.