Cranioplasty infection rates: what the numbers mean

How often does infection happen?

A 2021 analysis pooling 31 studies found infection in 463 of 4,667 cranioplasties, about 8%.¹ In a 2024 series from two German hospitals, surgical site infection was the single most common complication, affecting 13.7% of patients.⁸

The wide range reflects real differences between hospitals and patients, and also how long each study followed people. Some infections appear months after surgery, so short studies can undercount them.²

Does the implant material matter?

A 2025 review of 3,260 custom-made implants reported these rates:²

The authors caution that these aren't a fair head-to-head ranking. Titanium and composite studies had the shortest follow-up, which may underestimate their infection rates, while PMMA and hydroxyapatite studies followed patients longest.²

Other analyses point the same way for PMMA (acrylic bone cement):

• Methyl methacrylate carried 1.62 times the infection risk of the patient's own bone in one network meta-analysis.³
• A 2026 network meta-analysis linked PMMA to higher infection, and ranked PEEK and titanium lowest for infection.⁴

Patient-specific implants made by 3D printing were linked to fewer infections than standard implants in a 2025 meta-analysis (odds ratio 0.33).⁵

Individual hospitals can look very different from the averages. The German two-center series found infection in 28.6% of PEEK implants and 1.7% of PMMA implants, roughly the reverse of the pooled numbers.⁸ For a deeper comparison of the two most common custom materials, see PEEK vs titanium.

What may raise the risk?

Many studies have looked for risk factors, but the results are mixed. A 2026 reanalysis found that smaller studies tend to report bigger effects, and that some well-known "risk factors" weaken or reverse once study size is taken into account.⁹ With that caution, here is what specific studies found:

• Emergency surgery and diabetes. In a series of 960 stored bone flaps, infection was higher after emergency craniectomy (8.8% vs 2.6%) and in patients with diabetes (10.5% vs 3.1%).⁷ The 2026 reanalysis found the emergency-surgery link did not hold up in larger studies.⁹
• Head injury as the original cause. Patients whose craniectomy followed a traumatic brain injury had no higher infection risk than other patients.⁶
• Timing. Doing cranioplasty earlier or later did not change infection odds in a meta-analysis of severe head injury patients.¹⁰

Things you can control still matter for healing in general: stopping smoking, keeping blood sugar in range, and following wound care instructions exactly. See the first-week-home guide.

Signs of infection to watch for

• Redness, warmth or swelling around the incision that is getting worse¹¹
• Pus or fluid leaking from the wound, or the incision opening¹¹
• Fever or chills¹¹
• Pain at the site that gets worse instead of better¹¹

Infections can appear weeks or months after surgery, not just in the first days. Call your surgeon's office promptly if you notice any of these.

What happens if an implant gets infected?

Treatment depends on how deep and how severe the infection is, and your surgical team decides the approach. Some infections are treated without removing the implant. In the 2025 review, the share of implants removed was lower than the infection rate for most materials, which suggests many infections were managed with the implant left in place.²

When an infection can't be cleared, the implant may need to be removed, and a new cranioplasty is typically considered only after the infection has fully healed. In one children's series, two of three infected bone flaps that were removed were later put back successfully.¹² Your surgeon will explain the options for your situation.

Questions to ask your surgeon

1. What is the infection rate for this operation in your practice?
2. Does anything about my health raise my infection risk, and what can I do about it?
3. Will I get antibiotics before or after surgery?
4. Which signs should make me call you, and who do I call after hours?
5. If an infection happens, what would the plan be?

Sources

1. Henry J, et al. Complications of cranioplasty in relation to material: systematic review, network meta-analysis and meta-regression. Neurosurgery. 2021;89(3):383-394. doi:10.1093/neuros/nyab180
2. Faedo F, et al. Infection rates following custom-made cranioplasty using heterologous materials: a systematic review on 3260 patients with a focus on follow-up length. Neurosurg Rev. 2025;48(1):657. doi:10.1007/s10143-025-03818-1
3. Khalid SI, et al. Materials used in cranial reconstruction: a systematic review and meta-analysis. World Neurosurg. 2022;164:e945-e963. doi:10.1016/j.wneu.2022.05.073
4. Samandar AF, et al. Complications of alloplastic graft materials used in cranioplasty: systematic review and network meta-analysis. Med Sci Monit. 2026;32:e950551. doi:10.12659/MSM.950551
5. Di Cosmo L, et al. Meta-analyses of the surgical outcomes using personalized 3D-printed titanium and PEEK vs. standard implants in cranial reconstruction. Neurosurg Rev. 2025;48(1):312. doi:10.1007/s10143-025-03470-9
6. Henry J, et al. Complications of cranioplasty following decompressive craniectomy for traumatic brain injury: systematic review and meta-analysis. Acta Neurochir. 2021;163(5):1423-1435. doi:10.1007/s00701-021-04809-z
7. Fan MC, et al. Cryopreservation of autologous cranial bone flaps for cranioplasty: a large sample retrospective study. World Neurosurg. 2018;109:e853-e859. doi:10.1016/j.wneu.2017.10.112
8. Pfnür A, et al. Exploring complications following cranioplasty after decompressive hemicraniectomy: a retrospective bicenter assessment of autologous, PMMA and CAD implants. Neurosurg Rev. 2024;47(1):72. doi:10.1007/s10143-024-02309-z
9. Wang B, et al. Effect moderation and heterogeneity in meta-analysis: a meta-regression-based reinterpretation of surgical site infection risk factors after craniotomy and cranioplasty. J Clin Epidemiol. 2026;199:112428. doi:10.1016/j.jclinepi.2026.112428
10. Palavani LB, et al. Timing matters: a comprehensive meta-analysis on the optimal period for cranioplasty after severe traumatic brain injury. Oper Neurosurg. 2025;29(1):1-18. doi:10.1227/ons.0000000000001404
11. UMass Memorial Health. Discharge instructions for craniotomy. ummhealth.org/health-library/discharge-instructions-for-craniotomy
12. Josan VA, et al. Cranioplasty in children. Childs Nerv Syst. 2005;21(3):200-204. doi:10.1007/s00381-004-1068-2