PMC5954791_01
Frontal view of the cranial defect after craniotomy
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Fig1
A 10 year old male patient presented with a severe head trauma after falling from a roof that required an immediate decompressive craniotomy (Fig. 1).
CT showing a 12 x 12 cm right cranial defect. The prosthetic design was done using a computer system (DICOM) to design and produce a customized prosthesis in acrylic resin
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Fig2
A CT revealed a 12 cm by 12 cm defect (Fig. 2).
A Prosthesis placement on the patient. B Immediate postoperative period. C Patient before being discharged (2 days after surgery)
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Fig3
The prosthesis was fashioned and the patient was operated 10 days later (Fig. 3).
PMC5954791_02
Preoperative and immediate postoperative photos. Left column, preoperative patient status. Center column, PLA prosthesis adjusted to the cranial defect on a mannequin. Right column, immediate postoperative patient status
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Fig4
The patient had a bifrontal 20 cm cranial defect from the temporal fossa of one side to the other and 10 cm vertical distance (Fig. 4).
Digital design of the customized prosthesis
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Fig5
A boolean operation is applied to the volumes Vleft and Vright: Vimplant = Vleft - Vright (Fig. 5).
3D printing of the cranial defect and of the customized PLA prosthesis
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Fig6
A CUBE 3D (from 3D System) printer is used to print out a PLA prosthesis from the STL file using a fused deposition model by means of a 1,75 mm filament at a 260  C extruder temperature (Fig. 6).
A Cranial defect printout. B PLA customized prosthesis. C Assembled models to test precision
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Fig7
Once the printing process is finished, which takes about 20 h, the scaffolds are removed with a low-speed motor and a carbide bur and the adjustment is verified (Fig. 7).
A PLA prosthesis plaster impressions in metal containers. B Internal and external mold filling with PMMA. C. Comparison of the PMMA prosthesis to be implanted as an identical replica of the PLA prosthesis
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Fig8
The casts are opened and the prosthesis is revealed after a 25-min polymerization time (Fig. 8).
A Oblique mannequin view showing the 3D printout of the rim surrounding the defect. B Lateral view of the customized implant placed on the rim to cover the defect. C Frontal view of prosthesis to cranium coaptation
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Fig9
Precise anatomical compliance to the model is verified and approved by the multi-disciplinary team (including the neurosurgeons), and the prosthesis is then placed on a mannequin for academic and illustrative purposes (Fig. 9).
Ethylene oxide sterilized prosthesis
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Fig10
After obtaining the prosthesis in the laboratory, it is washed with normal saline solution and then submerged in a chlorine based antiseptic solution (Microdacyn 60 by Oculus lnnovative Sciences in Petaluma, CA.) for 15 min before taking it to the hospital where it is sterilized with ethylene oxide gas before its implantation (Fig. 10).
Placement and fixation with titanium plates
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Fig11
The prostheses were then placed over each of the defects to adjust them in vivo with minimum adjustments with the same low-speed electric motor, and fixed with 3 long titanium bridge plates, each held down with 2 screws (Fig. 11).
A Case Report 1 postoperative CT. Notice the coaptation of the prosthesis to the bone defect. B Case Report 2 postoperative CT. Notice the expansion of the frontal lobes on these axial plane images which were collapsed preoperatively
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Fig12
The patients were hospitalized for 2 days and discharged after a single drain is removed from each patient to continue their care as outpatients (Fig. 12).
6-month postoperative follow-up on our patient in Case 1 shows a great cranial symmetry, and wound healing
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Fig13