None of several materials used to reconstruct skull defects is fully satisfactory, due to biological and physical properties. In large defects or in defects with more complex geometries, the preoperative prefabrication of a custom polymethylmethacrylate (PMMA) implant based on a three dimensional model could be the best choice. From January 2007 to December 2010 PMMA custom made cranioplasty have been implanted in 44 patients (22M/22F; age range 17-82) at the Neurosurgery Unit of the Arcispedale S. Anna of the University Hospital of Ferrara, Italy. The causes of primary operation were 25 (56.8%) cerebral hemorrhages, 15 (34.1%) traumas, 3 (6.8%) tumors and 1 (2.3%) infection, respectively. Hypertension was a co-morbidity factor in 13 (29.5%) patients. Cranial vault reconstruction was performed after a mean period of 9 months. The variables analyzed were causes of craniotomy (hemorrhages, traumas, tumors and infections), co-morbidity factor (i.e. hypertension), sites (1 frontal, 8 fronto-temporal, 32 fronto-temporo-parietal, 2 temporo-parietal and 1 temporo-occipito-parietal) and dimension of the defect (maximum diameter smaller than 9 cm, 9 ≤ x < 12 cm, equal or greater than 12 cm). Each patient obtained an good aesthetic result. In two cases the reconstruction was removed in the follow-up period: one case of infected reconstruction and case of mobility of the prothesis. PMMA custom-made devices from processing of CT images can be used for produce cranial prothesies which have a low rate of infection and mobilit
