Patient-specific reconstruction utilizing computer assisted 3D modelling for partial bone flap defect in hybrid cranioplasty
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Date
2017
Authors
Hueh, Low Peh
Journal Title
Journal ISSN
Volume Title
Publisher
Pusat Pengajian Sains Perubatan, Universiti Sains Malaysia
Abstract
Background: Autologous cranioplasty using a patient’s original bone flap
remain the commonest practice nowadays. However, partial bone flap defect is
commonly encountered. Replacing the bone flap with pre-moulded synthetic
bone flap is costly and might not be affordable for all patients. Hence, some
small to medium size defects were topped up with alloplastic material on a free
hand basis intra-operatively that often resulted in inaccurate implant
approximation with unsatisfactory cosmetic result. This rationale the need for an
alternative technique for reconstruction of partial bone flap defect in
cranioplasty. The objective of this study is to evaluate implant accuracy and
cosmetic outcome of cranioplasty candidates with partial bone flap defect who
underwent reconstruction utilising computer assisted 3D modelling.
Methods: This study consisted of thirteen patients. 3D images of their skull
were obtained from post-craniectomy axial 1-mm spiral computed tomography
(CT) scans and virtual 3D models were generated using Materialise Mimics
software. The Materialise 3-Matic was utilised to design patient-specific
implant. Prefabrication of the implant performed by a 3D Objet printer, and
negative gypsum molds were created with the prefabricated cranial implant.
Intra-operatively, hybrid polymethyl methacrylate (PMMA)-autologous cranial
implants were produced using the gypsum molds, and fit into the cranial defect.
Results: Thirteen patients underwent partial bone flap reconstruction utilising
this technique. One patient involved in motor vehicle accident prior to outcome
!assessment; another patient experienced implant exposure and underwent
implant removal. The rest of the patients revealed satisfactory implant alignment
with favourable cosmesis. The mean visual analogue scale for cosmesis (VASC)
was 91, mean implant size was 50cm2, and the mean duration of intra-operative
reconstruction for the partial bone flap defect was 30 minutes. All of them
revealed excellent implant alignment and improvement in quality of life
following surgery as measured by the SF-36 score. Cost analysis revealed that
this technique is more cost-effective compared to customized cranial prostheses.
The cost of a customized cranial prosthesis range from RM10,000 to RM15,000
depending on the size of cranial defect. Whereas the production cost for an
individualized hybrid PMMA-autologous bone implant using this technique
range from RM 3,000 to RM 4,000.
Conclusion: This new technique and approach produces hybrid autologousalloplastic
bone flap that resulted in satisfactory implant alignment and
favourable cosmetic outcome with relatively low costs.
Description
Keywords
Skull , Abnormalities