An unusual foreign body in the oral cavity: a case report from a patient safety point of view and literature review.

Accidental foreign bodies (FBs) in the oral cavity, airway, esophagus and breathing circuit associated with anesthetic procedures are rare but can cause serious and life-threatening complications. We here present a case in which an unusual FB in the oral cavity was found after emergence from general anesthesia. The FB was later identified as a melted cap of a felt-tip pen. We investigated the cleaning process for reusable materials and concluded that the FB was accidentally placed in the inner lumen of the reusable bite block during the cleaning process. We then performed a review of the literature on FBs other than those of dental origin which were entrapped in the oral cavity, pharynx, larynx, trachea, esophagus, and anesthetic breathing circuit due to anesthetic procedures. From our case and 53 cases found in the search, we concluded that 1) use of disposable medical devices is recommended, 2) FBs can easily migrate into the oral cavity and airway during anesthesia, 3) delayed FB recognition may be associated with difficult intubation situations, and 4) more attention should be paid to the possibility of any medical or non-medical device becoming an FB during anesthesia.