Clinical Risk and Medico-Legal Implications in Zygomatic Implant Rehabilitation: An Umbrella Review of Systematic Reviews

Background: Zygomatic implants (ZIs) were initially pioneered by Brånemark to rehabilitate patients suffering from destructive diseases through original surgical technique (OST). Subsequently, other techniques were proposed, such as the zygomatic anatomy-guided approach (ZAGA). This umbrella review was conceived to quantify and critically characterize the spectrum of complications associated with different techniques of ZI placement. Methods: Systematic reviews, encompassing both those with and without meta-analysis, focusing on the complications associate with ZIs and published only in the English language were systematically sought. A systematic literature search was performed through MEDLINE/Pubmed, Scopus, BioMed Central, and the Cochrane Library, and the PROSPERO register. Results: A total of 11 articles were included. The latter documented the spectrum of complications associated with ZIs, ranging from minor morbidities such as sinusitis, hematoma, and soft tissue complications up to severe adverse events such as orbital penetration and diplopia. Conclusions: The use of described ZI OST and ZAGA in cases of severe maxillary resorption is associated with a high implant survival rate and a low incidence of surgical complications. However, complications, the most common of which were sinusitis and peri-implant soft tissue infection, may be underestimated due to the heterogeneity of the studies included.