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Hydroxyapatite ceramic implants for cranioplasty in children: a retrospective evaluation of clinical outcome and
Pietro Spennato1, Valentina Canella2, Ferdinado Aliberti3
1Department of Neurosurgery Santobono-Pausipilon children's hospital, Naples, Italy. pierospen@gmail.com.
Insights
Hydroxyapatite ceramic implants show promise for pediatric cranioplasty, with measurable bone ingrowth and osteointegration. While some fractures occurred, this material offers a viable alternative for skull reconstruction in children.
Area of Science:
- Neurosurgery
- Biomaterials Science
- Pediatric Orthopedics
Background:
- Pediatric cranioplasty presents unique challenges due to skull growth, thin bone, and high rates of cerebrospinal fluid disorders.
- Autologous bone is the gold standard, but alloplastic materials are considered when it's unavailable.
- Hydroxyapatite (HAP) offers a bone-like chemical composition, making it a valuable alternative.
Purpose of the Study:
- To evaluate the efficacy and outcomes of custom-made porous hydroxyapatite (HAP) implants in pediatric cranioplasty.
- To assess bone ingrowth and osteointegration of HAP implants in children.
Main Methods:
- Retrospective review of 11 pediatric patients (ages 3-16) who received HAP cranioplasty implants.
- Follow-up CT scans up to 48 months post-surgery to assess bone ingrowth and osteointegration.
- Bone density measurement at the bone-implant interface using the Hounsfield scale.
Main Results:
- Osteointegration was measurable in 12 out of 15 HAP implants (mean 51%).
- Six asymptomatic prosthesis fractures (40%) occurred within 6 months post-implantation.
- One case required explantation and replacement due to bifrontal prosthesis issues, representing the only revision surgery.
Conclusions:
- Hydroxyapatite ceramic implants are a viable option for pediatric cranioplasty.
- Successful osteointegration enhances implant mechanical resistance over time.
- HAP provides a valuable alternative to other cranioplasty solutions in pediatric cases.
Introduction:
Cranioplasty in children is a controversial and challenging issue, since there is still no consensus on the ideal material. Main problems in paediatric age are represented by the child's growing skull, the lower bone thickness and the high incidence of cerebrospinal fluid (CSF) disorders or brain swelling. Autologous bone is still considered the "gold standard". When it is not available, a wide range of alloplastic materials have been proposed. Hydroxyapatite, a ceramic-based derivative, bears a chemical composition very similar to the human natural bone, making this material a valuable alternative to other cranioplasty solutions.
Methods:
All patients implanted with a custom-made porous hydroxyapatite device at Santobono-Pausilipon Hospital in Naples were retrospectively reviewed. A follow-up CT scan of the skull was performed from 1 up to 48 months postoperatively to document the bone ingrowth as well as the osteointegration process. The bone density was measured as according to the Hounsfield scale at the bone-implant interface.
Results:
Between 2014 and 2018, 11 patients (7 males, 4 females) underwent cranioplasty with hydroxyapatite ceramic implants (HAP). Patients' age ranged between 3 and 16 years old. Initial aetiology was trauma in most cases. Two subjects were implanted with HAP as primary cranioplasty, 9 as revision surgery following previous cranioplasty failure. Sites of the cranial defect were unilateral fronto-temporo-parietal (N = 8), unilateral frontal (N = 1) and bifrontal (N = 2). Two patients with large bilateral defects received two prostheses. In one of these, the two prostheses were explanted and replaced with two back-up implants (accounting for a total of 15 implants in 11 patients). Osteointegration was measurable for 12 out of 15 implanted devices. The mean percentage was about 51%. There were six asymptomatic prosthesis fractures (40%), all occurring within 6 months from implant. In one case, the bifrontal prostheses were explanted and replaced. This was the only patient who underwent revision surgery.
Conclusion:
Hydroxyapatite ceramic implants represent a valid alternative to other cranioplasty solutions. Where coaptation occurs correctly, with good osteointegration, implant mechanical resistance increases over time.
