ECTS Abstracts (2015) 1 P432

A Maxillo-Facial Operation in a Patient with Fibrodysplasia Ossificans Progressiva (FOP): are we Ready for it?

Elisabeth (Marelise) Eekhoff1, Robert Van Es2, Annelies Van Schie1, Pieter Raijmakers1, Pim de Graaf1, Jan-Paul Klein1, Dimitra Micha1, Gerard Pals1, Teun de Vries3, Nathalie Bravenboer1 & Coen Netelenbos1

1VU university medical center, Amsterdam, The Netherlands; 2University Medical Center Utrecht, Utrecht, The Netherlands; 3Academic Center for Dentistry Amsterdam, Amsterdam, The Netherlands.

Background: Fibrodysplasia Ossificans Progressive (FOP) is rare disease characterised by progressive heterotopic ossifications during life leading to extremely disabling immobility, thoracic insufficiency and early death. The underlying cause is a mutation in the activin A type I receptor gene. In FOP skeletal muscles and connective tissues are being replaced by heterotopic bone which may be induced by small traumas or not well understood flare-ups. The course is chronic but unpredictable. No medical options are available and operations strongly discouraged. We present the course of FOP in a Dutch patient aged 23 who insisted on oral facial operation after 13 years of progressive mandible-maxillar occlusion with progressive limitations of food intake and vomiting.

Methods: The clinical history was followed from diagnosis FOP in 2001 along with blood tests of infection and bone formation parameters. In 2001 and 2014 before the maxillo-facial operation bone scans (technetium-99m bound to oxidronaat), combined bone scan-single-photon emission computed tomographic and FDG-PET scans of the head were performed. After the operation on November 14th 2014 18F-fluoride PET scan and magnetic resonance imaging were performed. Classical FOP mutation was confirmed.

Results: In 2001, after a fall the patient developed increasing occlusion of the mandibular-maxilla with ongoing uptake of the bone scan tracer first at the left os zygoma and later at left maxilla with progressive bone volume locally. During the operation, ectopic bone fusing left zygoma to mandible and occlusive ectopic bone around the right coronoid processes were removed. Despite high dose of corticosteroids severe clinical as radiographical flare-up of both left and right masseter and temporalis muscles developed. Experimental therapy was started. The outcome will be known and presented during the ECTS.

Conclusion: Operation in FOP is still hazardous due to lack of therapeutically options. We showed that flare-ups can be measured by advanced combined scans.

Disclosure: The authors declared no competing interests.