Maxillary reconstruction is still an evolving art when compared to the reconstruction of the mandible. The defects of maxilla apart from affecting the functions of the speech, swallowing and mastication also cause cosmetic disfigurement. Rehabilitation of the form and function in patients with maxillary defects is either by using an obturator prosthesis or by a surgical reconstruction. Literature is abundant with a variety of reconstructive methods. The classification systems are also varied, with no universal acceptance of any one of them. The oncologic safety of these procedures is still debated, and conclusive evidence in this regard has not emerged yet. Management of the orbit is also not yet addressed properly. Tissue engineering, that has been hyped to be one of the possible solutions for this vexing reconstructive problem, has not come out with reliable and reproducible results so far. This review article discusses the rationale and oncological safety of the reconstructing the maxillary defects, critically analyzes the classification systems, offers the different reconstructive methods and touches upon the controversies in this subject. The management of the retained and exenterated orbit associated with maxillectomy is reviewed. The surgical morbidity, complications and the recent advances in this field are also looked into. An algorithm, based on our experience, is presented.
1 October 2021 in International Journal of Nanomedicine
Background: Radiotherapy is an important treatment modality for many types of head and neck squamous cell carcinomas. Nanomaterials comprised of high atomic number (Z) elements are novel radiosensitizers enhance radiation injury by production of free radicals and subsequent DNA damage. Gold nanoparticles are upcoming as promising radiosensitizers due to their high (Z) biocompatibility, and ease for surface engineering. Bimetallic nanoparticles have shown enhanced anticancer activity compared to monometallic nanoparticles. Materials and Methods: PEG-coated Au–Ag alloy nanoparticles (BNPs) were synthesized using facile one pot synthesis techniques. Size of ∼ 50± 5nm measured by dynamic light scattering. Morphology, structural composition and elemental mapping were analyzed by electron microscopy and SAXS (small-angle X-ray scattering). The radiosensitization effects on KB oral cancer cells were evaluated by irradiation with 6MV X-rays on linear accelerator. Nuclear damage was imaged using confocal microscopy staining cells with Hoechst stain. Computed tomography (CT) contrast enhancement of BNPs was compared to that of the clinically used agent, Omnipaque. Results: BNPs were synthesized using PEG 600 as reducing and stabilizing agent. The surface charge of well dispersed colloidal BNPs solution was − 5mV. Electron microscopy reveals spherical morphology. HAADF-STEM and elemental mapping studies showed that the constituent metals were Au and Ag intermixed nanoalloy. Hydrodynamic diameter was ∼ 50± 5nm due to PEG layer and water molecules absorption. SAXS measurement confirmed BNPs size around 35nm. Raman shift of around 20 cm− 1 was observed when BNPs were coated with PEG. 1H NMR showed extended involvement of −OH in synthesis. BNPs efficiently enter cytoplasm of KB cells and demonstrated potent in vitro radiosensitization with enhancement ratio ∼ 1.5– 1.7. Imaging Hoechst-stained nuclei demonstrated apoptosis in a dose-dependent manner. BNPs exhibit better CT contrast enhancement ability compared to Omnipaque. Conclusion: This bimetallic intermix nanoparticles could serve a dual function as radiosensitizer and CT contrast agent against oral cancers, and by extension possibly other cancers as well.