Septic complication following porous hydroxyapatite cranioplasty: prosthesis retention management

After failing of autologous cranioplasty or when the bone flap is unavailable, the alloplastic (heterologous) materials are the choice for cranial reconstruction. No agreement has been reported about the material with a significant lower risk of septic complications. This is due to extremely heterogeneous prognostic factors related not only to the material used but also to the surgical procedures and/or to the timing of the procedure. More attention should be focused on the material whose characteristic could enable a delay in bacterial colonization, where an antibiotic therapy could be effective, without need of prosthesis removal. Four cases of severe septic complication following cranioplasty with porous hydroxyapatite (HA) prosthesis are presented. Patients were conservatively treated, without heterologous bone flap removal. All of our patients presented reasons for delaying HA cranioplasty removal: patients #1, 3, and 4 had an associated shunted hydrocephalus and the need for not removing the prosthesis was related to the predictable recurrence of overshunting and/or sinking skin flap syndrome. In patient #4, the revision surgery would have also damaged the microvascular flap with latissimus dorsi muscle used by plastic surgeon for skin reconstruction. In patient #2, the patient refused revision surgery. In all cases, systemic and/or radiological signs of infection were observed. In patient #2 the infective process surrounded completely the HA prosthesis, while it was located in the epidural region in patients #1 and 4. In patient #3, a surgical curettage of the infected wound was performed over the HA prosthesis. Following prosthesis retention management with antibiotic therapy, all patients revealed systemic and/or radiological signs of sepsis resolution at follow-up. The possibility to avoid a prosthesis removal with effective antibiotic treatment is mainly due to the combination of three factors: targeted antibiotic therapy, good anatomical area revascularization (resulting of an "in situ" intake of antibiotics), and the biomimetism of HA prosthesis. Further investigations in a larger number of cases need to confirm these observations.