gms | German Medical Science

Objective: Complex craniosynostosis (e.g. coronal plagiocephaly, trigonocephaly, multisuture synostosis or skull malformation of unknown etiology) requires complex and prolonged cranioplastic procedures with a high risk of comorbidity (blood loss, temperature decrease, cerebrospinal fluid leak, air embolism…) while most of the treated patients are still infants. Also, the cosmetic results are not always as expected: As evaluation during surgery is time consuming and difficult to obtain, one often remains uncertain determining where to saw, how far to mobilise, how to rotate and how to fix the bone flaps. Certainly in cases of coronal plagiocephaly, when one has to decide how far to advance and how to incline the orbital rim, preoperative planning could be of valuable help. Therefore, we decided to realise three-dimensional skull models in dental wax, enabling us to prepare surgery.

Methods: With 1 mm thick and contiguously sliced CT scan of the skull in bone windowing, three-dimensional skull models were created in methylacrylate bij Materialise, a corporation at Leuven, Belgium. At our department, by using negative casts in silicone, various copies of these methylacrylate models were produced in dental wax. These wax models proved anatomically exact and were easy and cheap to manufacture. They were extremely useful in preparing surgery as we could easily cut “bone flaps” with heated knives. These “bone flaps” could be bent, broken, rotated and fixed as in real surgery. However, realising these wax models was time consuming (in the range of 5 hours in a period of 2 days).

Results: From March 2005 up to now, we performed cranioplasty on 7 patients with the help of three-dimensional skull modelling. Two patients suffered from unilateral coronal plagiocephaly, (5m old male, 5m old female), one from multisuture craniosynostosis (6m old male with Apert’s syndrom), three from trigonocephaly (5m old male, 8m old male, 6y old male) and one from a malformation in the maxillofrontotemporonasal region of unknown etiology (17y old male). Surgery was performed in a faster and more confident way on those 7 patients. None of the patients suffered from complications related to surgery. Apart from postoperative respiratory infection problems, no significant postop morbidity was encountered. None of these patients needed to be reoperated. We are confident that surgical comorbidity was reduced and that cosmetic outcome improved significantly thanks to the preoperative planning on the wax models.

Conclusions: In spite of the very limited number of patients and the time-consuming preparation, we consider preoperative three-dimensional skull modelling in dental wax as an affordable, reliable, very helpful tool, allowing a reduction in operative duration and therefore comorbidity and to significantly improve cosmetic outcome. We will continue this preoperative planning in cases of complex craniosynostosis.