153 Clinical Course | Crouzon AN Information about the types of surgeries and the chronology of these events was collected. Surgeries were categorized as 1) vault expansion, 2) midface surgery, 3) CSF diverting surgery, 4) respiratory improvement (nonfacial surgery), and 5) other. Brain Measurements All measurements were performed on MRI and/or CT studies, which were acquired on a 1.5-T scanner (GE Healthcare, MR Signa Excite HD). The size of the lateral ventricles was evaluated on axial MRI and CT scans. The fronto-occipital horn ratio (FOHR) was calculated as (frontal horn width + occipital horn width)/biparietal diameter × 2. The lateral ventricles were considered enlarged if the FOHR was ≥ 0.4. This resulting ratio of ventricle size can be interpreted independent of age. 10, 11 Hydrocephalus was diagnosed when enlargement of the ventricles was progressive on two MRI or CT scans. Tonsil position was determined on MRI and/or CT scans as the position of the lowest cerebellar tonsil in millimeters above or below the foramen magnum and was measured as a continuous variable in millimeters. The foramen magnum was defined by the line between the basion and opisthion. A line perpendicular to the foramen magnum line was drawn to the tip of the cerebellar tonsils. A positive position corresponded with tonsillar herniation, whereas a negative measurement indicated a more rostral position of the cerebellar tonsil. Tonsil position was analyzed as a continuous variable. Additionally, the degree of tonsillar herniation below the foramen magnum was divided into two categories: < 5 mm and ≥ 5 mm.12-14 Considerations in Decision-Making from a Craniofacial Center Standpoint At all three centers, ICH is defined by a combination of signs of raised intracranial pressure such as hydrocephalus, papilledema, and indirect signs on radiological imaging or by raised intracranial pressure detected with an invasive measurement.15 In general, the treatment strategies at the three centers are similar: vault expansion, endoscopic third ventriculostomy (ETV) or ventriculoperitoneal (VP) shunt placement to treat hydrocephalus, midface surgery to improve midface hypoplasia, and foramen magnum decompression (FMD) to relieve brainstem compression. Redo vault expansion is required in cases of ICH. Posterior vault decompression can be combined with an FMD. However, the timing and order of interventions seem to differ among the centers. Erasmus Medical Centre, Rotterdam, The Netherlands Erasmus Medical Centre Rotterdam performs vault expansion early as the first treatment. Occipital expansion with springs is the first choice and is scheduled around the patient age of 5 to 6 months. If hydrocephalus develops before this age, vault expansion is scheduled earlier. When hydrocephalus appears after vault expansion, shunt placement or ETV will be considered. If the initial ventricular enlargement 9
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