Each material below is a real option in current practice. None is best for every patient. Defect size and location, scalp quality, prior infection, age, imaging needs, and surgeon experience all shape the choice.
The patient's own bone
Reference pointStored flapSplit calvarial graft
The piece removed during craniectomy can be frozen in a tissue bank or stored under the skin of the abdomen, then replaced later. It costs nothing to manufacture and is living tissue, but stored bone can slowly dissolve after it is put back, which is called resorption.
Strengths
- The patient's own tissue
- No implant manufacturing
- Fresh, unstored bone grafts had the lowest complication rates in one meta-analysis7
Trade-offs
- Resorption occurred in 15.1% of autologous cases and 0% of alloplastic cases in a network meta-analysis4
- Higher resorption in children and after long storage8
- Flap may be unusable if contaminated or fragmented
Clinical detail
- In 960 cryopreserved flaps, resorption was 9.38% in patients 18 or younger vs 3.61% in adults; graft infection was higher after emergency craniectomy (8.81% vs 2.59%) and in diabetic patients (10.53% vs 3.07%).8 Another cryopreserved series reported 21.6% overall resorption.9
- TBI is a risk factor for aseptic bone flap resorption (RR 1.54) and for reoperation in autologous cranioplasty (RR 1.49) but not in alloplastic cranioplasty.10
- Note that the favorable autologous data in Oberoi et al. describe fresh, heterotopic cranial bone grafts, a different population from stored craniectomy flaps.7
PMMA (acrylic bone cement)
Hand-molded in surgeryPrefabricated, patient-specific
Polymethylmethacrylate is a hard acrylic plastic with a long history in skull repair. It can be mixed and shaped by hand during surgery, where it hardens in place, or manufactured in advance to match the patient's CT scan.
Strengths
- Widely available and inexpensive
- Shows little interference on CT and MRI
- Can be made patient-specific at low cost, including in low-resource settings22
Trade-offs
- Does not grow into bone
- Hand-shaped fit depends on surgeon technique
- Several analyses associate it with higher infection or re-surgery rates11,13
Clinical detail
- Evidence is mixed. A 2018 meta-analysis (1,278 cranioplasties) found no difference in complications between PMMA and autologous bone (RR 0.98) or titanium (RR 1.59, NS).12
- A network meta-analysis found methyl methacrylate carried 1.62 times the infection risk of autologous bone.11 A 2026 network meta-analysis of alloplasts associated PMMA with higher infection and the highest re-surgery ranking.13
- Revision rates by format in one NMA: hand-molded 18%, prefabricated 9%.6 A single-center audit found reoperation in 28% of custom PMMA vs 6.5% of porous hydroxyapatite.19
PEEK (polyetheretherketone)
Patient-specificMachined or 3D printed
PEEK is a high-performance medical plastic. Cranial PEEK implants are made in advance from the patient's CT scan, so they arrive shaped to fit. PEEK does not block X-rays, which makes follow-up imaging easy to read.
Strengths
- Pre-shaped to the defect
- Very little imaging interference
- Lowest revision rate among materials in one network meta-analysis6
Trade-offs
- Does not grow into bone
- Requires manufacturing lead time
- Infection and hematoma rates still comparable to other substitutes5
Clinical detail
- PEEK revision was 5% (8/157) with RR 0.39 vs titanium and 0.20 vs autograft in one NMA.6
- Against titanium, PEEK had lower overall complications (OR 0.51) and implant exposure (OR 0.17), with no difference in infection or hematoma.5
- An earlier meta-analysis of 183 PEEK patients found a trend toward fewer complications than autologous grafts and fewer failures than titanium mesh, limited by small numbers.16
- Pooled all-cause complication rate 18.5% and failure 6.3% in studies with 12+ months follow-up.7 3D-printed PEEK showed no difference from standard implants (OR 1.02).15
Titanium
Mesh, shaped in surgeryPatient-specific milledPatient-specific 3D printed
Titanium is a strong, lightweight metal widely used in medical implants. It comes as flat mesh that the surgeon bends to shape, or as a patient-specific plate designed from the CT scan and then milled or 3D printed. Printing can build features like fixation tabs and porous structures directly into the part.
Strengths
- High strength in a thin profile
- Fewer hematomas and fit problems than non-titanium implants in a meta-analysis14
- Shorter hospital stay than autologous bone in one analysis11
Trade-offs
- Higher risk of the implant showing through the scalp (exposure)14,13
- Causes some artifact on CT scans17
- Hand-bent mesh fit depends on technique
Clinical detail
- Across 2,258 procedures, titanium had lower overall complications (OR 0.72), hematoma (OR 0.31) and imprecise fitting (OR 0.35), but higher implant exposure (OR 4.11).14 Dehiscence was higher with titanium than autologous bone (RR 0.34 favoring autologous).4
- Length of stay averaged 3.62 days shorter with titanium vs autologous bone.11 Titanium had lower reoperation than autologous bone, driven by resorption, with comparable cost and infection.21
- A 2025 meta-analysis found 3D-printed titanium implants reduced total complications vs standard implants (OR 0.26); 3D-printed implants overall had lower infection (OR 0.33) but more effusion (OR 2.20).15 A 40-patient series of 3D-printed titanium mesh PSIs reported no complications requiring reoperation.17
- Exposure risk is the practical counterweight: scalp thickness, prior radiation, and prior wound breakdown deserve weight in material selection.
Hydroxyapatite and bioceramics
Custom porousCalcium phosphate
Hydroxyapatite is the main mineral in natural bone. Custom porous hydroxyapatite implants are designed from CT and are built so the patient's bone can grow into them over time, a process called osseointegration.
Strengths
- Can integrate with surrounding bone19
- Low infection in a 2-year multicenter series18
Trade-offs
- Brittle; can fracture with trauma18
- Associated with higher re-surgery in a 2026 network meta-analysis13
Clinical detail
- Of 51 patients followed 2 years with custom porous HA, one infection occurred; three implants fractured after trauma and healed spontaneously, with no spontaneous fractures.18
- A single-center audit reported osseointegration in 69% of porous HA vs 24% of PMMA (level 3 evidence).19 HA revision rate 12% in one NMA.6
Porous polyethylene
Sheets shaped in surgeryCustom
High-density porous polyethylene is a flexible plastic with tiny interconnected pores that surrounding soft tissue can grow into. It is easy to trim and is widely used across face and skull reconstruction.
Strengths
- Easy handling and trimming
- Low overall complication rate in a systematic review20
Trade-offs
- Fewer head-to-head comparisons than other materials
- More complications in repeat operations at the same site20
Clinical detail
A 2024 systematic review of 1,104 HDPP cranioplasties (defects 3 to 340 cm²) found a 2.3% overall complication rate, higher in secondary cranioplasty, with reported patient satisfaction of 98.3% where measured. Most included studies were not comparative.20