Fibrodysplasia ossificans progressiva (FOP) is a rare, progressive, and disabling autosomal dominant disorder of. The diaphragm, tongue, extraocular, and laryngeal muscles are spared from heterotopic ossification; cardiac and smooth muscles are also not affected. Individuals with FOP appear normal at birth except for malformations of the great toes. During the first decade of life, inflammatory soft tissue swellings, also known as flare-ups, transform skeletal muscles and connective tissues into a second skeleton of heterotopic bone that progressively immobilizes all of the joints of the axial and appendicular skeleton. Flare-ups may occur spontaneously, but can be precipitated by misplaced venipuncture, soft tissue injury, muscle fatigue, intramuscular injection, biopsy or excision of heterotopic bone, viral illnesses, routine dental therapy, and injection of local anaesthetics during dental procedures.
Disease flare-ups are episodic; immobility is cumulative. Heterotopic ossification usually begins by ten years of age with neck and shoulder involvement. The temporomandibular joints may be involved early and are vulnerable to trauma at any age. The median lifespan is 40 years; death results most commonly from complications of thoracic insufficiency syndrome or pneumonia. A few deaths have been attributed to complications of general anaesthesia. At the present time, no medical or surgical intervention can alter the natural history of FOP. Anaesthetic management for patients with FOP is challenging. Cervical spine fusion, ankylosis of the temporomandibular joints, thoracic insufficiency syndrome, restrictive chest wall disease, and sensitivity to oral trauma complicate airway management and anaesthesia.