====== Hydroxyapatite Cranioplasty ======

{{rss>https://pubmed.ncbi.nlm.nih.gov/rss/search/1HECjjBSq9BhoRtSm7FL-OYBpqatdqX2a4XjM-Qpb7CBS0IQiv/?limit=15&utm_campaign=pubmed-2&fc=20230910094427}}

Among [[alloplastic]] materials, [[bioceramics]] such as microporous and macroporous hydroxyapatite (HA) have been extensively used as a [[bone graft]] substitute because the crystalline phase of HA is similar to the [[bone mineral]] component.

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Morbidity is high following [[cranioplasty]], with over a tenth requiring explantation. Hydroxyapatite and [[acrylic]] were associated with reduced risk of all-cause [[explantation]] and explantation due to [[infection]]. Cranioplasty insertion at three to six months was associated with increased risk of explantation due to infection
((Millward CP, Doherty JA, Mustafa MA, Humphries TJ, Islim AI, Richardson GE, Clynch AL, Gillespie CS, Keshwara SM, Kolamunnage-Dona R, Brodbelt AR, Jenkinson MD, Duncan C, Sinha A, McMahon CJ. Cranioplasty with hydroxyapatite or acrylic is associated with a reduced risk of all-cause and infection-associated explantation. Br J Neurosurg. 2022 May 24:1-9. doi: 10.1080/02688697.2022.2077311. Epub ahead of print. PMID: 35608052.)).

===== Custom made cranioplasty of porous hydroxyapatite =====

see [[Custom made cranioplasty of porous hydroxyapatite]].

===== Case series =====
A retrospective study of patients with a hydroxyapatite implant from 2010 to 2014 at our neurosurgical department was conducted. Demographic, surgical and radiological data were studied. A senior neuroradiologist, a staff member neurosurgeon and a resident neurosurgeon independently performed the radiological evaluation. A new software analysis technique was developed to objectively quantify the degree of osteointegration.

Seventeen implants were evaluated with an average patient age of 39 years and a mean follow-up of 155 weeks. Through radiologic evaluation, osseous bridging was deemed higher than 50% in six prostheses and higher than 75% in three. In five patients, no osteointegration could be seen. The remaining patients exhibited sparse signs of osteointegration, estimated between 10 and 50%. Software analysis showed an average osteointegration ratio of 37.4% with a 400-HU filter and 27.3% with a 700-HU filter.

In this small retrospective study of cranial hydroxyapatite implants, osteointegration did occur and to a degree of more than 50% in 1/3 of the patients
((Maenhoudt W, Hallaert G, Kalala JP, Baert E, Dewaele F, Bauters W, Van Roost D. Hydroxyapatite cranioplasty: a retrospective evaluation of osteointegration in 17 cases. Acta Neurochir (Wien). 2018 Nov;160(11):2117-2124. doi: 10.1007/s00701-018-3694-6. Epub 2018 Oct 2. PMID: 30276548.)).