S3-02 SESSION 3: FACIOCRANIOSYNOSTOSIS – PART I CRANIAL FOSSA DEVELOPMENT IN DIFFERING SUBTYPES OF CROUZON SYNDROME

Abstract

Introduction: Based on an established classification system of Crouzon syndrome subtypes, detailed regional morphology and volume analysis may be useful, in order to add additional clarification to Crouzon cranial structure characteristics, and the interaction between syndrome, suture fusion and gene regulated overall growth of the calvarium and basicranium. Methods: CT scans of 36 unoperated Crouzon syndrome and 56 controls were included and subgrouped as: type I. Bilateral coronal synostosis; type II. Sagittal synostosis; type III. Pansynostosis; type IV. Perpendicular combination synostosis. Results: Type I of Crouzon syndrome patients developed a slightly smaller posterior cranial fossa (22%), and increased superior cranial volume (13%), which is the only subtype that develops a greater superior cranial volume. The effect of competing increases and decreased segmented volume causes a 24% enlargement of overall cranial volume (p=0.321). In class III, the anterior cranial fossa volume was increased by 31% (p=0.007), while the volume of posterior cranial fossa was decreased by 19% (p<0.001). This resulted in a 7% (p=0.046) reduction in the overall intracranial volume. Type II and type IV patients developed a trend toward anterior, middle, posterior fossa and entire cranial volume reduction, although none of these decreases reached statistical significance. Conclusion: Pansynostosis is the most often form of associated craniosynostoses of Crouzon syndrome. Bilateral coronal synostosis may not dominate all forms of Crouzon syndrome. Individualized treatment planning for Crouzon syndrome patient, thoracically, should be taken into account, factors such as the patient’s age, and temporally associated suture involvement, for both anterior and posterior cranial fossae surgery.