The choice of materials for 3D printed cranial repair implants is crucial to surgical outcomes and patient rehabilitation. PEEK (polyetheretherketone) and titanium alloy are two materials commonly used in clinical practice

 

3D Printing Cranial Repair Implant Materials: PEEK vs. Titanium

 

The choice of skull repair implant material is critical to surgical outcomes and patient recovery. PEEK (polyetheretherketone) and titanium alloy are two materials commonly used in clinical practice, and they have significant differences in performance and application scenarios. The following is a detailed comparison of the two from multiple dimensions:

 

Comparison of material properties

 

1. Biocompatibility

 

Titanium alloy:
Advantages: It has good biocompatibility, high affinity with human tissues, and is not easy to cause rejection reaction when implanted in the body for a long time, and is a traditional implant material for orthopedic and craniomaxillofacial surgery.
Disadvantages: A very small number of patients may be allergic to titanium, resulting in local inflammation or skin reactions.

 

PEEK：
Advantages: Excellent biocompatibility, no release of metal ions, very low risk of allergies, and non-toxic materials, meeting the requirements for long-term implantation.
Disadvantages: As a polymer material, its direct binding ability with bone tissue is slightly weak (it needs to be enhanced by surface modification).

 

2. Mechanical properties

 

Titanium alloy:
Advantages: high strength (tensile strength of about 800-1200 MPa), high hardness, can withstand large external force, suitable for repairing skull defects in the stressed part.
Disadvantages: The modulus of elasticity (about 110 GPa) is much higher than that of human bone (10-30 GPa), which may produce a "stress masking effect", resulting in resorption of surrounding bone tissue.

 

PEEK：
Advantages: The modulus of elasticity (about 3-4 GPa) is closer to the bone, the stress distribution is more uniform, which can reduce stress occlusion and promote bone tissue growth.
Disadvantages: The strength of pure PEEK is slightly lower than that of titanium alloy (tensile strength about 90-100 MPa),

 

3. Imaging compatibility

 

Titanium alloy:
Disadvantages: Metal materials can produce obvious artifacts in CT and MRI examinations, which affect the evaluation of intracranial conditions (such as cerebral edema and tumor recurrence) after surgery.

 

PEEK：
Advantages: non-metallic materials, no imaging artifacts, CT, MRI and other examinations can be clearly performed after surgery, which is convenient for long-term follow-up.

 

4. Processing and shaping capabilities

 

Titanium alloy:
Advantages: It can be prefabricated or shaped intraoperatively by stamping, cutting, 3D printing and other processes to adapt to complex skull shapes.
Disadvantages: The traditional titanium mesh needs to be manually shaped by the doctor, and the accuracy may be limited; Customized titanium plates need to be 3D printed, which is costly.

 

PEEK：
Advantages: It can be precisely customized with 3D printing technology to fully fit the shape of the skull defect, and the material can be shaped by heat (about 150-200°C), allowing for more flexibility during surgery.
Disadvantages: The processing equipment is demanding and relies on 3D printing technology, which may not be available in some hospitals.

 

5. Corrosion resistance and stability

 

Titanium alloy:
Advantages: It has strong corrosion resistance in the human body fluid environment, is not easy to oxidize or degrade, and has high stability for long-term implantation.

 

PEEK：
Advantages: excellent chemical stability, resistance to acid, alkali and body fluid corrosion, no risk of degradation, can be used for life.

 

6. Cost and Accessibility

 

Titanium alloy:
Advantages: The cost of materials is low, the price of traditional titanium mesh is close to the people, and it is widely used in grassroots hospitals.
Disadvantages: Customized titanium plates are more expensive and rely on 3D printing technology.

 

PEEK：
Disadvantages: The high cost of the material itself, coupled with the cost of 3D printing customization, the overall price is significantly higher than that of titanium alloy (about 2-5 times that of titanium alloy), which may be difficult for some patients to afford.
 

 

 

Comparison of clinical application scenarios

 

1. Applicable patient type

 

Titanium alloy:
It is suitable for patients with limited economic conditions and a large and regular-shaped skull defect.
Indicated in patients who do not have a high need for postoperative imaging (e.g., skull repair alone).

 

PEEK：
It is suitable for patients with high requirements for imaging examinations (such as regular follow-up after brain tumor surgery).
It is suitable for patients with complex skull defects and those who are looking for aesthetic repair (such as facial skull defects).
Suitable for pediatric patients (PEEK can deform slightly as the skull grows, reducing the risk of secondary surgery).
 

2. Risk of surgical complications

 

Titanium alloy:
Risks: The metal edges may rub against the scalp causing pain or skin abrasion, and the infection rate is about 1% to 3% after surgery.

 

PEEK：
Risks: If the fit of the material to the edge of the bone window is insufficient, cerebrospinal fluid leakage or material displacement may occur, and precise surgical operation is required.
 

3. Long-term results

 

Titanium alloy:
After long-term implantation, bone resorption may be caused by stress occlusion, and some patients need to be adjusted by secondary surgery.

 

PEEK：
Because the mechanical properties are closer to those of bone, the risk of bone resorption is lower and the long-term stability is better.
 

Summary and selection suggestions

 

Compare dimensions	Titanium alloy	PEEK
advantage	Low cost, high strength, long application history	Good imaging compatibility, good mechanical matching, and customizable
inferior position	imaging artifacts, stress occlusion, possible allergies	High cost, 3D printing dependent, slightly less intensive
Recommended scenario	The economy is limited, simple defects, and there is little need for short-term review	Complex defects, requiring long-term imaging monitoring, pediatric patients

 

Selection Principle:

 

If the patient is concerned about cost-effectiveness and the regular shape of the defect, titanium alloys (especially traditional titanium mesh) are preferred.

 

PEEK is a preferred choice for patients who require high precision in postoperative testing (eg, neurosurgical follow-up), who are looking for aesthetic restoration, or who are pediatric patients.

 

The doctor will make a comprehensive assessment based on the patient's specific situation (such as the location of the defect, financial status, and postoperative management needs) and formulate a personalized plan.
 

Development of 3D printed skull repair implants

 

Improvement of PEEK: Through hydroxyapatite coating, nanofiber modification and other technologies, the binding ability of PEEK to bone tissue is enhanced, and the osseointegration effect is further improved.

 

Innovation of titanium alloys: Porous titanium alloys (simulating the porous structure of bones) can promote the growth of bone cells and reduce stress shielding, which has gradually become the development direction of titanium alloy implants.