Segmental and cavity-shaped bone losses are treated surgically. There are three alternatives:
Harvesting of the bone on the patient (autogenous)
The bone graft is harvested from an anatomically distant place (like the iliac crest). It is the most frequent approach since the autogenous bone has a perfect immunological compatibility, and contains cells and several growth factors that stimulate the repairing of the bone ad integrum. But this solution is damaging for the graft harvesting site. As a consequence, surgical risks of infection and haemorrhage are higher, postoperative management and follow-up are heavier, and the amount of available bone is limited.
Using bone banks (living or deceased patients)
The bone is harvested from living or deceased donors, after a surgery (femoral head), on human bodies after the death of the individual (allograft), or animals (xenograft). This bone is stored in a tissue bank and addresses a need for a consequent amount of bone, but presents immunological or infectious risks.
Compensating bone losses with synthetic materials
The inconvenience of autografts and bone grafts explains the increasing use of synthetic materials. Their amount is unlimited and they present no immunological or infectious risks. According to their type, these biocompatible materials are:
- Biologically tolerated: metals (titanium for example) and polymers like PMMA (poly-methyl-methacrylate) or PEEK (Poly Ether Ether Ketone) that compensate the loss but replace the bone. They are tolerated by the organism but often cause the formation of reactive fibrous tissue.
- Inert: alumina or zircon ceramics do not cause any biological reaction in the organism.
- Bioactive : as the chemical composition of the material is similar to the composition of mineral bones, the calcium phosphates are identified by the cells as autogenous bone. The implants are porous and guide the ingrowth of the bone cells, being thus the best candidates to compensate a bone loss. They are available in standard forms that have to be adapted or tailored directly from the medical imaging of the patient for a more accurate anatomical adaptation and better cells ingrowth.