Rotational tomography of the normal and reconstructed middle ear in temporal bones: an experimental study.

Imaging is an essential diagnostic tool in reconstructive middle ear surgery, especially in pre-operative planning. Due to ongoing improvement of imaging quality and development of new imaging techniques like e.g. rotational tomography (RT) post-operative follow-up and immediate evaluation of surgical results may become more important. The aim of this experimental study was to evaluate RT as a new tool for postoperative determination of middle ear anatomy and implant position in temporal bones. RT was performed in ten temporal bone specimen after insertion of different middle ear prostheses concerning material, shape and length (PORP; TORP; Stapes piston). An implantable hearing device (Symphonix Soundbridge) was also implanted and visualized. For comparison some specimen additionally underwent conventional computed tomography (CT), including the newest technology. Characterization of anatomical structures of the temporal bone using RT was of comparable quality to conventional CT-scans in all investigated specimen while requiring approximately 30% of the CT's irradiation exposure. Unlike CT the RT showed almost no problems due to metallic artefacts of the implanted prostheses. Furthermore RT enabled a 3-dimensional view of the temporal bone and angle determination of inserted prostheses towards the tympanic membrane and/or the malleus handle. Detailed imaging of the prostheses allowed determination of shape, material and localization within the specimen's reconstructed middle ear. The new imaging technique of RT allows precise presentation of anatomical structures and middle ear implants in temporal bones. Following these experimental results it will be our future work to evaluate this method in clinical practise.

[The valence of dilatational tracheotomy]. / Zur Wertigkeit der Dilatationstracheotomie.

After standardizing surgical procedures around 1900 Shelden, Toye, Weinstein and Ciaglia developed the percutaneous dilational tracheotomy (PDT). At present it is recognized that about 50 % of the anesthesiological Intensive care Units (ICU) in Germany are using the PDT while favoring the Ciaglia-technique in the majority of cases. Further techniques are known as Griggs-, Fantoni-, Percu-Twist- and Blue-Rhino-method. Some of these are relatively new, therefore making critical comparison with other methods almost impossible due to lack of experience. The most feared complications of PDT are injury of the cricoid cartilage or of the rear tracheal wall as well as paratracheal positioning of a tracheotomy tube. Comparison between PDT and surgical techniques are difficult due to certain contraindications for PDT which are not valid for surgical procedures. Consecutively PDT will not be able to substitute surgical tracheotomy in the future. It furthermore can't be advocated as an alternative therapeutic option for mobile in-patients outside the ICU.