Successful use of the laryngeal mask airway supreme in a patient with craneo-cervical dystonia during magnetic resonance imaging

Editor—The classic laryngeal mask (LMA-C) airway is a helpful device in maintaining an adequate airway during magnetic resonance imaging (MRI). 2 With the exception of the MRI-safe-LMA, all LMAs have a variable quantity of ferromagnetic material that could reduce image quality, or potentially affect the patient security with respect to movement or dislodgement. 4 The Laryngeal Mask Airway Supreme (LMA-S) is a new disposable LMA with gastric access, and at this time, there are no data available on the use of the LMA-S during MRI. We report a case of a man who underwent brain MRI, which was managed successfully using an LMA-S. A 69-yr-old man with a history of craneo-cervical dystonia presented for brain MRI. He suffered from involuntary contractions affecting the orbicular muscle of the eye, oromandibular and neck muscles, and in the proximal muscles of his left arm, with important visual disability and dysphagia. On examination, he suffered involuntary spasms, a marked torticollis with restricted neck movements and a Mallampati grade 1. General anaesthesia was induced with fentanyl and propofol without a neuromuscular blocking agent. After induction, the movements of the head and neck disappeared, and a size-4 LMA-S was easily introduced and successful at the first attempt and a suction catheter was passed into the drainage tube. Anaesthesia was maintained with sevoflurane in spontaneous ventilation. The procedure was completed uneventfully with a good image quality without artifacts and the LMA-S was removed without incidence. This is the first reported case of the use of the LMA-S to secure the airway during MRI. Tracheal tubes or LMAs have been the standard of care for cases that need general anaesthesia. The radiologists usually are familiar with the effect on imaging interpretations produced by the metallic spring in the pilot balloon or anatomic distortions induced by the LMAs, although there are some reports of misdiagnosis as a result of the LMAs. – 8 Any magnetic material can reduce the image quality depending on the quantity of magnetic material within the field, the pulse sequence that is used, and if the area of interest is in the region to the LMA. When the MRI is done in close proximity to the LMA-Flexible, LMA-ProSeal, or LMA-Fastrach tracheal tube, there will be distortion of the image due to the wire component of the airway tube and heating. With the LMM-S, we optimized the airway, without the risk of produce artifacts or compromising the patient’s airway. Although the LMA-S has not been previously tested for MRI compatibility, we used it because its characteristics (medical grade PVC) and the small amount of metal within the valve in the pilot balloon similar to the LMA-Classic. The patient had a history of dysphagia, and an LMA with gastric access could offer more security. We conclude that the LMA-S is potentially useful during MRI.