Crouzon syndrome:a clinical and three dimensional radiographic analysis of craniofacial morphology and surgery

Abstract

The clinical and radiographic appearance of Crouzon syndrome has been analysed for a population of 59 patients. The range of cranio-facial manifestations (and non cranio-facial features) and the natural history of the deformity provide an insight into the pathological processes occurring in Crouzon syndrome. The medical and surgical management of patients with this deformity is discussed. The cranio-facial morphology of Crouzon syndrome has been analysed using cranio-facial osseous landmark co-ordinate data in three dimensions. The landmark co-ordinate data were determined from computer tomography records of 8 patients with Crouzon syndrome (in 4 different age groups). In addition, osseous landmark co-ordinate data were determined from computer tomography records of age-matched normal dried skulls. These data provided an experimental standard of normal cranio-facial morphology and were used for comparison with the data collected from the patients with Crouzon syndrome to generate a mathematical description of the morphology of this syndrome. The accuracy of landmark co-ordinate identification was assessed. Measurements of the size and shape of individual cranio-facial bones were made to demonstrate the morphology of each bone (anatomical units) including the sutures and synchondroses. A statistical comparison of individual cranio-facial bones of each Crouzon patient with the agematched experin1ental standards revealed areas of significant variation from nonnal. As with the clinical data, variability between patients and between age groups was revealed. Specific patterns of morphology for the individual bones in Crouzon syndrome were determined. The ~etailed analysis of the severity and extent of the deformities provided insight into understanding of the pathological forces which contribute to the malformation and provided substantial morphological information upon which strategies for surgical intervention can be based. The nature of the surgical intervention in each of 5 patients was analysed from osseous landmark co-ordinate data derived from the bony elements before and after surgical modification (surgical units), although only short term follow up was available f..o.r analysis. A comparison of the dimensions of the pre-operative surgical unit with those of the experimenra.l standard surgical unit further demonstrated the pathological morphology of this condition. The distance of surgical shift of each bony component was measured by comparison of the preoperative surgical unit with the post-operative surgical unit. This enabled analysis of the methods undertaken and the effectiveness of surgical manoeuvres on patient morphology. Comparison of the post-operative surgical unit with the experimental standard demonstrated the extent of the variation from the experimental standard remaining after surgery. While surgery dealt with the functional considerations, the morphological analysis demonstrated that only the facade of the pathology was manipulated in the patients examined. The present investigation demonstrates the clinical and radiographic features, in detail, of the craniofacial morphology of Crouzon syndrome. Quantification from three dimensional computed tomography reconstructions provides detailed infom1ation on the pathological morphology for each individual with Crouzon syndrome and is able to demonstrate some of the changes occurring immediately after surgical manipulation. This analysis, utilising a recently developed method, re-examines these issues and provides the framework for future developments in this field.