RESUMEN
We present the successful reconstruction of a large mandibular defect with a severe maxillofacial deformity after malignant tumor resection and irradiation. The patient was a 16-year-old boy with a defect in the left mandible, which extended from the mandibular body to the condylar process and hypoplasia of the maxillozygomatic complex on the left side as a result of ablation and radiotherapy of a grown rhabdomyosarcoma in the left infratemporal fossa at the age of 10. We planned a two-stage reconstruction because of his wide mandibular defect and hypoplasia. LeFort I type osteotomy to correct the maxillary declination was combined with mandibular lengthening to decrease the width of the defect in the first stage. New bone formation was confirmed at the distraction site 4 months after surgery, and the second stage was performed. A free latissimus dorsi myocutaneous flap with a vascularized scapula and rib was transferred to reconstruct the ramus of the mandible, zygomatic arch, and soft tissues. This procedure resulted in satisfactory results. In conclusion, the combination of distraction osteogenesis and microsurgical bone transplantation facilitated the straightforward reconstruction of a three-dimensional deformity with huge bony defects. We think that this combined surgical procedure will become a favorable option in the treatment of severe maxillomandibular deformities with bone defects.
Asunto(s)
Mandíbula/cirugía , Osteogénesis por Distracción/métodos , Osteotomía Le Fort/métodos , Procedimientos de Cirugía Plástica/métodos , Rabdomiosarcoma/cirugía , Adolescente , Trasplante Óseo/métodos , Niño , Humanos , Masculino , Rabdomiosarcoma/radioterapia , Cigoma/cirugíaRESUMEN
We propose a method to reduce cross talk by using single-mode filters, namely, extracting the fundamental mode from a multimode optical network (EFMON). The EFMON effect is evaluated for a three-step switching system consisting of cascade electro-optic (EO) waveguide prism deflector (WPD) micro-optical switches (MOSs) and a multimode waveguide network. The WPD MOS is optimized for single-mode operation in lead lanthanum zirconate titanate thin films as EO slab waveguides with a driving voltage of 12 V, a length of 310 microm, and a channel distance of 20 microm. Beam propagation method simulation reveals that mode disturbance, higher-order modes, and cross talk are accumulated by switching steps. A single-mode filter for EFMON in the output region of the switching system reduces cross talk to below -20 dB at a propagation length of 2000 microm in the single-mode filter and below -30 dB at 20000 microm.