Complications and cosmetic outcomes of materials used in cranioplasty following decompressive craniectomy-a systematic review, pairwise meta-analysis, and network meta-analysis.

Background: Optimal reconstruction materials for cranioplasty following decompressive craniectomy (DC) remain unclear. This systematic review, pairwise meta-analysis, and network meta-analysis compares cosmetic outcomes and complications of autologous bone grafts and alloplasts used for cranioplasty following DC.
Method: PubMed, Embase, and Cochrane were searched from inception until April 2021. A random-effects pairwise meta-analysis was used to compare pooled outcomes and 95% confidence intervals (CIs) of autologous bone to combined alloplasts. A frequentist network meta-analysis was subsequently conducted to compare multiple individual materials.
Results: Of 2033 articles screened, 30 studies were included, consisting of 29 observational studies and one randomized control trial. Overall complications were statistically significantly higher for autologous bone compared to combined alloplasts (RR = 1.56, 95%CI = 1.14-2.13), hydroxyapatite (RR = 2.60, 95%CI = 1.17-5.78), polymethylmethacrylate (RR = 1.50 95%CI = 1.08-2.08), and titanium (Ti) (RR = 1.56 95%CI = 1.03-2.37). Resorption occurred only in autologous bone (15.1%) and not in alloplasts (0.0%). When resorption was not considered, there was no difference in overall complications between autologous bone and combined alloplasts (RR = 1.00, 95%CI = 0.75-1.34), nor between any individual materials. Dehiscence was lower for autologous bone compared to combined alloplasts (RR = 0.39, 95%CI = 0.19-0.79) and Ti (RR = 0.34, 95%CI = 0.15-0.76). There was no difference between autologous bone and combined alloplasts with respect to infection (RR = 0.85, 95%CI = 0.56-1.30), migration (RR = 1.36, 95%CI = 0.63-2.93), hematoma (RR = 0.98, 95%CI = 0.53-1.79), seizures (RR = 0.83, 95%CI = 0.29-2.35), satisfactory cosmesis (RR = 0.88, 95%CI = 0.71-1.08), and reoperation (RR = 1.66, 95%CI = 0.90-3.08).
Conclusions: Bone resorption is only a consideration in autologous cranioplasty compared to bone substitutes explaining higher complications for autologous bone. Dehiscence is higher in alloplasts, particularly in Ti, compared to autologous bone.
(© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)