Tái tạo lõm thái dương sau tiêu xương sọ bằng mảnh ghép peek cá nhân hóa Patient-specific PEEK cranioplasty for postoperative temporal hollowing

Cranial reconstruction is not simply about replacing missing bone. In regions that directly influence facial contour, particularly the temporal area, the implant may need to be designed according to both the skeletal defect and the overlying soft-tissue volume.

This case demonstrates the use of three-dimensional planning and a patient-specific PEEK implant to address two related problems simultaneously: a cranial defect and postoperative temporal hollowing.

When the replaced cranial bone subsequently resorbs

The patient had previously sustained a traumatic brain injury requiring decompressive craniectomy. During this procedure, a portion of the skull was temporarily removed to accommodate cerebral swelling.

The cranial bone flap was subsequently replaced.

Over time, however, part of the right temporal bone underwent resorption, resulting in a secondary cranial defect and loss of structural support in the temporal region.

The most visible consequence was significant temporal hollowing, producing a clear asymmetry between the two sides of the face.

Temporal hollowing is not simply a bony defect

The contour of the temporal region is determined by the combined anatomy of the cranial skeleton, temporalis muscle, fat, and overlying soft tissues.

Following trauma or cranial surgery, the temporalis muscle may undergo atrophy, loss or alteration of its attachment, displacement, or changes in its relationship with the underlying skeleton. When cranial bone resorption occurs simultaneously, the structural support for the muscle and soft tissues may be further compromised.

In this patient, despite careful management of the temporalis during the previous procedure, resorption of the temporal bone removed part of its underlying support, allowing the muscle and surrounding tissues to displace medially and creating a pronounced temporal depression.

This raises an important reconstructive question:

If we simply replace the missing bone anatomically, will the external temporal contour also be restored?

Not necessarily.

Designing the reconstruction around both bone and soft tissue

Soft-tissue augmentation techniques such as autologous fat grafting can be used for temporal hollowing. However, retention of grafted fat volume can vary, and additional procedures may occasionally be required.

For this patient, a different strategy was selected: the unaffected side of the patient's own anatomy was used as the reference for the volume to be reconstructed.

First, the patient's imaging data were used to reconstruct a three-dimensional model of the skull. This model was provided to the manufacturer to generate the initial design of a patient-specific cranial implant.

In parallel, the volume of the unaffected temporalis muscle was reconstructed using Blender.

This volume was then mirrored to the affected side, providing a patient-specific three-dimensional reference for the desired temporal contour.

An implant designed to do more than replace missing bone

If the implant had simply reproduced the original bony surface, the loss of muscle and soft-tissue volume could have resulted in persistent temporal depression despite successful reconstruction of the cranial defect.

The initial implant design was therefore modified.

In selected areas, the implant was intentionally augmented beyond the reconstructed skeletal contour, using the mirrored soft-tissue volume from the unaffected side as a reference.

The design question therefore changed from:

“What bone is missing?”

to:

“What volume needs to be reconstructed to restore symmetry of the external contour?”

Once the design was finalized, the patient-specific implant was manufactured from PEEK (polyetheretherketone).

Collaboration between neurosurgery and maxillofacial surgery

The operation was performed through collaboration between neurosurgery and maxillofacial surgery.

After exposure of the cranial defect, the temporalis muscle and surrounding tissues were dissected and repositioned to accommodate the reconstructed contour.

The patient-specific PEEK implant was then placed to reconstruct the cranial defect while simultaneously providing the underlying volume required to support the temporal soft tissues.

Residual deformity of the zygomatic region was also addressed during the same procedure to improve continuity of the temporal–malar contour.

Three-month result

At three months after surgery, temporal symmetry had improved substantially.

Soft-tissue volume on the affected side was better restored, and the transition between the temporal and zygomatic regions appeared more natural.

The significance of this result lies not simply in successful closure of the cranial defect, but in the fact that the external facial contour had already been incorporated into the implant design before surgery.

Autologous bone or alloplastic reconstruction?

There is no single reconstructive material that is optimal for every craniofacial defect.

Autologous bone offers important biological advantages and can integrate with the patient's skeleton. However, grafted or replaced cranial bone may undergo variable resorption over time in certain clinical situations.

Alloplastic materials such as PEEK do not possess the biological bone-forming properties of autologous tissue, but they offer the ability to maintain a predefined geometry and to be manufactured according to the individual anatomy of the patient.

The choice between autologous and alloplastic reconstruction should therefore consider the location and dimensions of the defect, soft-tissue condition, previous operations, and the functional and aesthetic objectives of each patient.

From defect reconstruction to contour reconstruction

This case illustrates an important evolution in craniofacial reconstruction.

With three-dimensional planning, the question is no longer limited to how accurately an implant can fit a missing segment of the skull.

Patient-specific anatomical data can also be used to design the final contour that the reconstruction is intended to create.

This is particularly important in the temporal region, where external morphology is determined not only by the skeleton but also by the temporalis muscle and surrounding soft tissues.

A patient-specific implant may therefore sometimes need to be designed differently from the exact bone that was lost, with intentional augmentation to compensate for changes in the overlying soft tissues.

This represents one of the most important advantages of three-dimensional personalized reconstruction: the ability not only to replace what has been lost, but to design the reconstructive outcome for the individual patient.