Airflow inside the nasal cavity: visualization using computational fluid dynamics.

Background: It is of clinical importance to examine the nasal cavity pre-operatively on surgical treatments. However, there is no simple and easy way to measure airflow in the nasal cavity. Objectives: Visualize the flow features inside the nasal cavity using computational fluid dynamics (CFD) method, and study the effect of different breathing rates on nasal function. Method: A three-dimensional nasal cavity model was reconstructed based on computed tomographic images of a healthy Malaysian adult nose. Navier-Stokes and continuity equations for steady airflow were solved numerically to examine the inspiratory nasal flow. Results: The flow resistance obtained varied from 0.026 to 0.124 Pa.s/mL at flow-rate from 7.5 L/min to 40 L/min. Flow rates by breathing had significant influence on airflow velocity and wall shear-stress in the vestibule and nasal valve region. Conclusion: Airflow simulations based on CFD is most useful for better understanding of flow phenomenon inside the nasal cavity.

Perforation of oesophagus and aorta by an unusual migratory fish bone: case report.

This report describes a migratory fish bone which was not found during 1st surgery causing perforation to the superior part of the arch of aorta. The patient presented with feeling of something stucked in her throat after eating fish subsequently followed by progressive excruciating pain in the neck. During 2nd surgery the fish bone was found to have migrated from the superior aspect of the arch of aorta to the anterolateral aspect of the arch of aorta after piercing the aortic lumen. We report a case of migratory fish bone which was not found during 1st surgery. The clinical examination of the throat revealed no foreign body. The CT scan of the neck and upper thorax demonstrated a 1cm linear foreign body part of which had perforated into the superior part of the arch of aorta with mediastinal hematoma. The most likely cause was a fish bone. The patient's condition slowly deteriorated, median sternotomy and exploration of mediastinum then followed. Unfortunately no fish bone was found and only mediastinal hematoma was discovered. After the first operation the patient condition did not improve and repeat CT scan of the neck and upper thorax was done 3 days later. A similar foreign body has now moved from the superior aspect of the arch of aorta to the anterolateral aspect of arch of aorta. Exploration was done again and this time the fish bone was found.

Analysis of pediatric subdural empyema outcome in relation to computerized tomography brain scan.

A cross-sectional study was conducted to predict the outcome in patients with subdural empyema, using initial and post-treatment CT scan brain parameters. Data collection was done on those children who were diagnosed to have subdural empyema by CT scan of the brain with contrast, who underwent burrhole evacuation, from February 2000 until April 2002. Numerous factors, such as coma or loss of unconsciousness at diagnosis, age, types of antibiotic, microbiology, extension of empyema, associated cerebral infarction and ventriculitis, were analyzed. Poor prognosis was associated with loss of consciousness, and hypodensity by CT scan at presentation (p < 0.005). Patients with an extensive subdural empyema will have a good outcome if they are treated early and aggressively with antibiotics and burrhole evacuation.