In order to study the influence of tympanic membrane lesion and ossicular erosion caused by otitis media on the hearing compensation performance of round-window stimulation, a human ear finite element model including cochlear asymmetric structure was established by computed tomography (CT) technique and reverse engineering technique. The reliability of the model was verified by comparing with the published experimental data. Based on this model, the tympanic membrane lesion and ossicular erosion caused by otitis media were simulated by changing the corresponding tissue structure. Besides, these simulated diseases’ effects on the round-window stimulation were studied by comparing the corresponding basilar-membrane’s displacement at the frequency-dependent characteristic position. The results show that the thickening and the hardening of the tympanic membrane mainly deteriorated the hearing compensation performance of round-window stimulation in the low frequency; tympanic membrane perforation and the minor erosion of ossicle with ossicular chain connected slightly effected the hearing compensation performance of round-window stimulation. Whereas, different from the influence of the aforementioned lesions, the ossicular erosion involving the ossicular chain detachment increased its influence on performance of round-window stimulation at the low frequency. Therefore, the effect of otitis media on the hearing compensation performance of round-window stimulation should be considered comprehensively when designing its actuator, especially the low-frequency deterioration caused by the thickening and the hardening of the tympanic membrane; the actuator’s low-frequency output should be enhanced accordingly to ensure its postoperative hearing compensation performance.
Objective To investigate the value of laparoscopy in resetting and repairing of inguinal incarcerated hernia. Methods Clinical data of 11 patients with acute inguinal incarcerated hernia treated with laparoscopy from March 2007 to February 2008 were reviewed, including 3 cases of direct inguinal hernia and 8 cases of oblique inguinal hernia. Results There were 7 patients with incarcerated hernia who were reset automatically after general anaesthesia, and 4 patients who were reset with laparoscopy. All the hernias were repaired with the transabdominal preperitoneal (TAPP) method after observed or improved the blood cycle of the incarcerated intestinal tract under laparoscopy. Average follow-up time was 6.6 months (2-12 months) after operation. Good recover and no recurrence were showed in all patients. Conclusion Laparoscopy is a safe technology in resetting and repairing of inguinal incarcerated hernia