Radiologic and Anatomical Assessment of The Retrotympanum on a Latin American Population

By June 7, 2019

Monroy-Llaguno, Daniella Alejandra1; Gonzalez-Navarro, Mauricio2; Gonzalez Rosado, Garly Daniel3; Lupa-Mendlovic, Michelle1; Cisneros-Lesser, Juan Carlos1
1 Otolaryngology Department, Instituto Nacional de Rehabilitación. Mexico City, Mexico;
2 Department for Research on Infectious Diseases, Instituto Nacional de Enfermedades
Respiratorias, Mexico city, Mexico;
3 Radiology department Instituto Nacional de Rehabilitación. Mexico City, Mexico.

Introduction:
The retrotympanum houses many important structures; two anatomical elements of particular interest are the sinus tympani and subcochlear canaliculus, sites in which pathology can lodge in chronic ear disease.

Objectives:
Describe the sinus tympani, subcochlear canaliculus and the pneumatization of the mastoid process by computed tomography and anatomic dissection using the classifications proposed by Marchioni et al. and Han et al. in Mexican patients; correlate mastoid pneumatization and the development of the sinus tympani and the subcochlear canaliculus; determine interrater reliability for those scales between physicians (junior resident, senior resident, attending endoscopic surgeon and a radiologist).

Methods:
Analysis and classification of 196 tomographic studies and 20 temporal bone dissections.  Evaluations from a junior resident, senior resident, attending endoscopic surgeon and a radiology expert for the current classifications were obtained. These results were analyzed to determine the interrater reliability for those scales between physicians with varying levels of expertise on the field.

Results:
The most prevalent type of subcochlear canaliculus in our population is type C (55.1%), unlike the 23.07% reported by Marchioni et al. The most prevalent type of sinus tympani is type B (59.4%) and for the mastoid process was type IV (35.5%).
No clear correlation was found with the development of the sinus tympani or the subcochlear canaliculus with the pneumatization of the mastoid process.

Conclusion:
Experienced physicians had better reliability than junior residents, suggesting that the classification proposed by Marchionni et al. is reliable between experienced physicians. However junior residents may have trouble with its implementation.