Anatomical study of the pigs temporal bone by microdissection

PURPOSE:Initial study of the pig`s temporal bone anatomy in order to enable a new experimental model in ear surgery.METHODS: Dissection of five temporal bones of Sus scrofa pigs obtained from UNIFESP - Surgical Skills Laboratory, removed with hole saw to avoid any injury and stored in formaldehyde 10% for better conservation. The microdissection in all five temporal bone had the following steps: inspection of the outer part, external canal and tympanic membrane microscopy, mastoidectomy, removal of external ear canal and tympanic membrane, inspection of ossicular chain and middle ear.RESULTS: Anatomically it is located at the same position than in humans. Some landmarks usually found in humans are missing. The tympanic membrane of the pig showed to be very similar to the human, separating the external and the middle ear. The middle ear`s appearance is very similar than in humans. The ossicular chain is almost exactly the same, as well as the facial nerve, showing the same relationship with the lateral semicircular canal.CONCLUSION:The temporal bone of the pigs can be used as an alternative for training in ear surgery, especially due the facility to find it and its similarity with temporal bone of the humans.Federal University of São Paulo Paulista School of MedicineFederal University of São Paulo Medical SchoolUNIFESP, EPMSciEL

Anatomical study of the pigs temporal bone by microdissection

PURPOSE:Initial study of the pig`s temporal bone anatomy in order to enable a new experimental model in ear surgery.METHODS:Dissection of five temporal bones of Sus scrofa pigs obtained from UNIFESP - Surgical Skills Laboratory, removed with hole saw to avoid any injury and stored in formaldehyde 10% for better conservation. The microdissection in all five temporal bone had the following steps: inspection of the outer part, external canal and tympanic membrane microscopy, mastoidectomy, removal of external ear canal and tympanic membrane, inspection of ossicular chain and middle ear.RESULTS:Anatomically it is located at the same position than in humans. Some landmarks usually found in humans are missing. The tympanic membrane of the pig showed to be very similar to the human, separating the external and the middle ear. The middle ear`s appearance is very similar than in humans. The ossicular chain is almost exactly the same, as well as the facial nerve, showing the same relationship with the lateral semicircular canal.CONCLUSION:The temporal bone of the pigs can be used as an alternative for training in ear surgery, especially due the facility to find it and its similarity with temporal bone of the humans.Federal University of São Paulo Paulista School of MedicineFederal University of São Paulo Medical SchoolUNIFESP, EPMSciEL

Micro-endoscopic ear anatomy of guinea pig applied to experimental surgery

PURPOSE:To describe topographic and endoscopic anatomy of guinea pig ear for development of surgical approaches in experimental studies.METHODS:Experimental study. Eight adult guinea pigs (Cavia porcellus) were used in this study. Four animals were described through endoscopic view and four animals were used to describe topographic anatomy.RESULTS:The main structures of middle ear were well identified through endoscopy view: oval and round window, ossicles and vascular structures. Temporal bone position, landmarks and its relations to skull are perceived with topographic description.CONCLUSION:Topographic anatomic description allowed exposition of temporal bone relations for external surgical approaches. Alternatively, grooves and middle ear structures were identified and may be used to transcanal accesses.Federal University of São PauloFederal University - São PauloFederal University of São Paulo Neck Surgery DepartmentUNIFESP, Neck Surgery DepartmentSciEL

Tissue response evaluation of the mucosa of the tympanic cavity of guinea pigs, when receiving biodegradable implant

PURPOSE:To evaluate the tissue response of the mucosa of the tympanic cavity of guinea pigs, when receiving biodegradable implant.METHODS:A total of 20 male guinea pigs were divided into 2 groups. After paracentesis in both ears, a biodegradable polymer of poly lactic-co-glycolic acid was implanted in only one middle ear. Histological analysis using neutrophil exudate and vascular neoformation (acute inflammation) and fibroblast proliferation and mononuclear inflammatory cells (chronic inflammation) as parameters was performed after 10 and 30 days of survival (groups 1 and 2, respectively).RESULTS:Four ears in group 1 and 7 in group 2 had an increase of neutrophil exudate. Vascular neoformation occurred in ears with or without the implant, in both groups. Fibroblast proliferation and mononuclear inflammatory cells (lymphocytes and macrophages) increased in ears with implant in group 2.CONCLUSION:The tissue response by histological analysis of the mucosa of the tympanic cavity of guinea pigs, when receiving biodegradable implant, showed no statistically significant difference between ears with or without the implant.Universidade Federal de São Paulo (UNIFESP), Escola Paulista de Medicina (EPM) Department of OtorhinolaryngologyFederal University of Minas Gerais Faculty of PharmacyFederal University of Minas GeraisUSP Faculty of Medicine of Ribeirao PretoUniversidade Federal de São Paulo (UNIFESP), Escola Paulista de Medicina (EPM) Department of Otorhinolaryngology and Head and Neck SurgeryFederal University of São PauloFederal University of São Paulo Medical SchoolUNIFESP, EPM, Department of OtorhinolaryngologyUNIFESP, EPM, Department of Otorhinolaryngology and Head and Neck SurgeryUNIFESP, Medical SchoolSciEL

Transcanal endoscopic myringoplasty: a case series in a university center

ABSTRACT INTRODUCTION: Transcanal myringoplasty has the advantages of demanding lower operative time and minimal external incisions. It can be performed using the microscopic or endoscopic approach. In the last decade, the use of endoscopes in ear surgery has increased significantly. This technique may allow "around the corner" visualization of small recesses, through narrow spaces, without the aid of canalplasty in unfavorable ear canals. OBJECTIVE: To describe a case series of transcanal endoscopic myringoplasty performed in a university service. The characteristics, advantages, and disadvantages of this technique are also discussed. METHODS: A case series study, based on the chart review of patients submitted to transcanal endoscopic myringoplasty in the period from January of 2012 to October of 2014. RESULTS: Data from 22 patients were analyzed. Tympanic perforation closure three months after surgery was observed in 86.4% of all patients. There was statistically significant improvement in pure tone average thresholds after surgery (p < 0.001). CONCLUSION: Transcanal endoscopic myringoplasty is a feasible, safe, and effective procedure; it can be an alternative to microscopic surgery