A 40-year-old male patient presented with a post-traumatic cranial defect involving the left parietal region following the loss of a segment of calvarial bone. Due to the resulting cranial defect and the need for anatomical reconstruction, the patient was referred for the design and manufacturing of a patient-specific cranial implant (PSI).

Dr. Ali Ahmadi

• Neurosurgeon
• Fellowship-Trained Skull Base Surgeon

Pre-operative Planning

To achieve precise cranial reconstruction and optimal anatomical restoration, a comprehensive preoperative planning process was conducted using the patient’s computed tomography (CT) imaging data. DICOM images were imported into specialized medical engineering software, allowing accurate three-dimensional reconstruction of the cranial anatomy.
For reconstruction of the osseous defect, a mirroring technique was employed using the unaffected contralateral side of the skull as the anatomical template. Key craniofacial landmarks, including the nasion, supraorbital ridge, and zygomatic arch, were identified and utilized as reference points for establishing the patient’s mid-sagittal plane and anatomical symmetry. These landmarks played a critical role in restoring the native cranial contours and achieving optimal facial balance.

Following reconstruction of the defect geometry, a patient-specific cranial implant was designed while carefully considering biomechanical and biological requirements. Implant thickness was optimized to provide sufficient structural integrity while minimizing unnecessary weight. The thickness was maintained at 2 mm in regions flush with the surrounding bone and reduced to 1 mm in other areas.
A hybrid fixation strategy incorporating both fixation flanges and oblique screw fixation was implemented. Each flange was designed with a dedicated screw hole. The final design included seven fixation flanges and seven oblique fixation screws. Titanium screws with a diameter of 1.6 mm were selected for fixation. In the final design, the only externally prominent structures were the fixation flanges. The oblique screw trajectories were specifically engineered to prevent palpable prominence beneath the soft tissue while ensuring stable and reliable fixation.
To reduce pressure on underlying tissues and facilitate fluid exchange, multiple perforations were incorporated into the implant design. Additionally, a porous mesh architecture was adopted to decrease implant weight and improve adaptation to the surrounding tissues. This design strategy may also promote tissue integration and potentially reduce postoperative complications.
To further enhance surface characteristics and improve biological integration, both internal and external implant surfaces underwent controlled sandblasting, creating a uniform micro-roughened surface topography.
Finally, a trial implant was manufactured for preoperative assessment. This allowed intraoperative evaluation of dissection adequacy and preliminary fit verification before placement of the definitive implant. Such a step plays an important role in minimizing intraoperative adjustments and improving the accuracy of final implant positioning.

Surgical Treatment

Based on the extent of the cranial defect and the predetermined treatment plan, surgery was performed under general anesthesia. According to the operating surgeon’s preference, a coronal approach was utilized. Following elevation of the soft tissue flap, the cranial defect was fully exposed.
A trial implant was initially inserted to evaluate the adequacy of soft tissue dissection and verify preliminary implant adaptation. After confirmation of sufficient surgical exposure and appropriate fit, the patient-specific implant was positioned within the defect site.
The implant was then carefully assessed for marginal adaptation and conformity with the surrounding anatomical structures. Following verification of satisfactory fit and alignment, the implant was secured using titanium fixation screws to provide optimal primary stability. Particular attention was paid to avoiding undue pressure on underlying tissues and preserving adjacent critical anatomical structures throughout the fixation process.
After thorough irrigation of the surgical field, the soft tissue flap was repositioned and the wound was closed in anatomical layers. The patient was subsequently transferred to the recovery unit in stable condition.

Post-operative Follow-up

Following cranial reconstruction, the patient demonstrated a stable and satisfactory postoperative course. Clinical follow-up examinations confirmed excellent adaptation of the implant to the surrounding tissues without evidence of significant complications.
The operating surgeon expressed a high level of satisfaction with the surgical outcome, emphasizing that the precise implant design and utilization of advanced digital planning and manufacturing technologies significantly contributed to the success of the reconstruction and the patient’s overall recovery.
The patient also reported substantial improvement in both functional and psychological well-being, expressing satisfaction with the aesthetic outcome and renewed confidence regarding quality of life. Continued follow-up demonstrated favorable healing and successful restoration of cranial contour and symmetry.

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Cranial Bone Defect in a 40-Year-Old Male Patient | Dr. Ali Ahmadi