Comparison of capabilities and limitations of endoscopes in endoscopic ear surgeries using 3D printed models.

PURPOSE: Endoscopic ear surgery has become a popular operative approach to treat middle ear diseases. Surgeons use either 0° or 30° endoscopes worldwide. The main aim of the work was to compare the properties of these two types of endoscopes. MATERIAL AND METHODS: Since this type of evaluation is hard to perform in vivo during the actual surgery, we designed 3D printed temporal bone models with different levels of complexity. The evaluation of endoscopes was based on image analysis or visibility of anatomical structures. RESULTS: The results show that a 30° endoscope offers a view of lateral walls from 4 mm distance, contrary to a 0° endoscope which cannot see lateral walls from this distance at all. On the other hand, visible area of the anterior wall is up to 40 % larger using 0° endoscope, compared to 30° endoscope. Angled endoscope distorts the picture and leads to the deterioration of the image. At commonly used distances above 5 mm from middle ear structures, resolution and image distortion is comparable between both endoscopes. CONCLUSIONS: Our results do not offer a definitive opinion on which endoscope is better for ear surgery. Both types of endoscopes have advantages and disadvantages, and the choice depends on the surgeon's personal preference and on the type of planned procedure.

Optimal Light Source Intensity Setting in Endoscopic Ear Surgery.

HYPOTHESIS: Higher light intensity settings do not yield improved image quality in endoscopic ear surgery. BACKGROUND: Light intensity is a parameter with major impact on the quality of digital images. For ear surgery, light produces heat associated with a thermal risk to ear structures and the light source setting should be accordingly optimized. METHODS: Several series of still images were acquired during live middle ear surgery, using cadaveric and plastic temporal bone models and with three-dimensional printed models. Images obtained under varying light intensities were compared with the image acquired at maximum intensity of a light emitting diode light source. We analyzed digital image brightness and noise using quantitative methods. RESULTS: Our measurements revealed significantly decreased image brightness with light intensities set below 20% with an increase in noise at light intensities lower than 30%. CONCLUSION: The optimal light source setting corresponded to 30% intensity in our experimental set-up. Special attention should be given to those cases where faster image quality degradation is expected (dark or bloody scenes or larger cavities). The results were strongly dependent on the equipment used. The methods described in this study can serve as a general guide for determining the optimal light source setting in any specific set-up.

In Vivo Measurements of Middle Ear Temperature During Transcanal Endoscopic Ear Surgery.

OBJECTIVE: The light emitted from the endoscope during transcanal endoscopic ear surgery (TEES) heats the intratympanic space. This heat may potentially be dangerous to nearby important structures, as documented by in vitro and by animal and cadaveric studies. The aim of our work was to monitor middle ear temperatures during TEES in vivo. STUDY DESIGN: Cohort study. SETTING: Tertiary referral hospital. PATIENTS: Four patients (15-69 yrs old) underwent transcanal endoscopic tympanoplasties for chronic perforation or retraction. INTERVENTION: After elevating the tympanomeatal flap, a thermocouple was placed in the middle ear to measure the heat generated by a 30° Hopkins rod telescope (11 cm long, 2.7 mm wide) and fiberoptic light emitting diode light source. MAIN OUTCOME MEASURES: Middle ear temperature in the retrotympanum was monitored under these conditions: at 50 and 100% light intensity, after removing and wiping the endoscope tip, during suctioning and following middle ear irrigation. RESULTS: Maximum middle ear temperature ranged from 36.26-37.30°C. Pulling out and wiping the endoscope caused no change or minimal decrease of 0.16°C. Middle ear irrigation caused a temperature drop of 2.05°C to 5.11°C. Suctioning was associated with a drop from 0.24°C to 3.91°C that was dependent on the depth of the endoscopic tip. CONCLUSION: Middle ear temperatures during TEES using a Hopkins rod telescope and light-emitting diode light source reach values corresponding to physiological body temperature, and do not reach dangerous levels.

Coexistent neck enteric cyst and intraspinal neurenteric cyst: Embryopathogenetic implications.

INTRODUCTION: Enteric cysts are very rare conditions, occurring mainly in the posterior mediastinum and posterior neck. Their pathomorphology corresponds with that of intraspinal neurenteric cysts. Both formations are derivatives of the posterior foregut. However, their embryopathogenesis has not been elucidated satisfactorily as yet. For those associated with vertebral anomalies, the split notochord theory has been widely accepted. However, this is be hardly conceivable for cases free of these anomalies. CASE REPORT: Here, a patient with concurrent separated enteric and neurenteric cysts and cervical spine dysmorphism is presented. DISCUSSION: The review of the relevant literature revealed sporadic analogical cases in which a transvertebral communication between the two cysts was present or absent. The latter was associated with a minimal abnormality of the vertebral body. CONCLUSION: The authors suggest that normal vertebrae may be formed in patients with enteric cysts, which would make the notochord-split theory plausible also for those free of spinal malformations.

Chronic inflammation of the middle ear with cholesteatoma.

Cholesteatoma is a cystic pseudotumor. It is consisted of a keratinized squamous epithelium producing keratin masses. It occurs in purulent form of chronic otitis media. It can behave aggressively and cause osteolysis of surrounding structures in the middle ear, such as the middle ear bone, facial nerve channel, inner ear, etc. Diagnosis of cholesteatoma is based on otomicroscopy and the use of modern imaging methods (computed tomography, magnetic resonance imaging). The treatment is surgical and must be radical enough to prevent recurrence of the disease. Despite precise surgical technique, recurrence is relatively frequent, especially in childhood. Early diagnostics and adequate surgical therapy can prevent severe otogenic complications of middle ear inflammation.