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Biomedical subjects

R Mösges

Publications and source records attributed to R Mösges.

At least 19 recordsLinked to original sources
PubMed1996

Endoscopic surgery of the rhinobasis with a computer-assisted localizer.

The endoscope is useful for the diagnosis and surgical therapy of diseases of the nose, the paranasal sinuses and its neighboring regions, and allows for microinvasive, functional approaches. The reduced invasiveness of therapeutic procedures is sometimes accompanied by insufficient clearness of the surgical field, however. This significant problem is solved by the computer-assisted-surgery (CAS) system, an intraoperative localizer. It allows continuous orientation based on three-dimensional reconstructed preoperative CT scans with superimposed positioning of the endoscope. We have now adapted CAS for endoscopic sinus surgery, which meant that a variety of visualization methods were tested. A conventional straightforward endoscope was used in combination with, or as, the localizing probe. A dual-display technique was adjusted to video-endoscopic procedures: the information of the localizer is displayed on one monitor while the video-endoscopic picture is viewed on a second screen. In addition, a single-display technique with both images on one monitor was developed. It proved to be the most promising way of combining endoscopy and intraoperative CT-image-guided localization.

Endoscopes↗
PubMed1996

Sedation in allergic rhinitis is caused by the condition and not by antihistamine treatment.

Sedation is regarded as a common side-effect of most H1-antihistamines. This view must be accepted, yet can hardly be assessed under treatment of allergic disorders. Since central sedative potency is hard to evaluate, different methods of measurement have been introduced in the four phases of clinical investigation. While tests of high complexity in early trials can detect true central effects, they seem to have the disadvantage of not taking into consideration the important interactions of drugs with the disorder. Therefore, we used a visual analog scale (VAS) as an instrument to demonstrate sedative effects in five clinical studies carried out between 1989 and 1994 with a total number of 1070 patients. Thereby, we could assess the result of the different components of the central interaction. In 1989, in a double-blind, placebo-controlled trial, we could show that the vigilance of patients suffering from seasonal allergic rhinitis increased significantly more under treatment with an antihistamine (mizolastine) than under placebo. From 1992 until 1994, we compared azelastine nasal spray either by the double-dummy technique with oral antihistamines (cetirizine, loratadine, and astemizole) or by the double-dummy or placebo-controlled design with monotherapy or combined therapy with azelastine tablets. A marked or statistically significant improvement of vigilance was found for all compounds (loratadine: P < 0.0001; cetirizine: P < 0.0254; and azelastine nasal spray: P < 0.1409 to P < 0.0001). Even when taking azelastine as oral application, patients, in spite of the warning, reported a similar increase in vigilance (P < 0.2628 to P < 0.0001). Finally, we assessed the range of physiologic vigilance using the same VAS in healthy volunteers. In conclusion, we could prove that in all trials the baseline values of vigilance of untreated symptomatic patients were far below physiologic condition and improved under treatment to the upper range of healthy persons. Therefore, any sedative properties of modern H1-antihistamines should not limit their therapeutic use, since the truly threatening sedation results from the disorder itself.

Arousal↗
PubMed1996

[From quality control to quality assurance. An ISO-9000 oriented approach for the hospital].

Measures taken to assure medical quality in hospital departments have focused on external quality control. Public health insurance organizations and the society of hospital holders in Germany have now agreed to carry out activities that aims not only at outcome but also at structural and procedural aspects of medical quality. The next step will be the introduction of quality management systems according to ISO 9000.

Delivery of Health Care↗
PubMed1995

Computer-assisted image-guided surgery in pediatric skull-base procedures.

Skull-base surgery is characterized by the variety of important neural and vascular structures within a narrow operating field. Although preoperative imaging by computed tomography (CT) and magnetic resonance imaging (MRI) and the use of microsurgical techniques have improved intraoperative orientation, a large number of complications still are caused by localization problems. Especially in pediatric skull-base surgery, maximum localization accuracy during surgery is required. The authors developed a localizing system based on tomographic imaging (such as CT or MRI) to achieve safer surgery by providing highly accurate location information. The preliminary successful experience in the use of the Aachen computer-assisted surgery device for pediatric skull-base surgery (14 cases) is presented. Indication include juvenile angiofibroma of the nasopharynx, infectious and tumorous diseases of the paranasal sinuses, orbital tumors, foreign bodies, and intracranial abscess formation.

Adolescent↗
PubMed1995

Image- and model-based surgical planning in otolaryngology.

Preoperative evaluation of any operating field is essential for the preparation of surgical procedures. The relationship between pathology and adjacent structures, and anatomically dangerous sites need to be analyzed for the determination of intraoperative action. For the simulation of surgery using three-dimensional imaging or individually manufactured plastic patient models, the authors have worked out different procedures. A total of 481 surgical interventions in the maxillofacial region, paranasal sinuses, orbit, and the anterior and middle skull base, in addition to neurotologic procedures were presurgically simulated using three-dimensional imaging and image manipulation. An intraoperative simulation device, part of the Aachen Computer-Assisted Surgery System, had been applied in 407 of these cases. In seven patients, stereolithography was used to create plastic patient models for the preparation of reconstructive surgery and prostheses fabrication. The disadvantages of this process include time and cost; however, the advantages included (1) a better understanding of the anatomic relationships, (2) the feasibility of presurgical simulation of the prevailing procedure, (3) an improved intraoperative localization accuracy, (4) prostheses fabrication in reconstructive procedures with an approach to more accuracy, (5) permanent recordings for future requirements or reconstructions, and (6) improved residency education.

Child↗
PubMed1994

[Decompression of the optic nerve after fractures of the rhino-basal skull with computer-assisted surgery].

Referring to 22 cases of surgery after frontobasal fractures of different origin with loss of vision, the surgical procedure is discussed with special consideration of the approach, technique and timing of the operation. We conclude that the external rhinological approach through the ethmoid sinus is the best and easiest access in cases of loss of vision with verified fracture or haematoma. A number of patients were operated using CAS (Computer Assisted Surgery)-Systems, a CT-based tool for three-dimensional orientation. It proved to be very useful for the surgeon, saving time and reducing the risk of additional damage. According to our experience and the results of other authors we believe that surgical intervention should be performed as early as possible.

Blindness↗
PubMed1993

New trends in head and neck imaging.

The development of novel imaging techniques has exerted a larger influence on medical science than have any other advances in the last decade. The following occurrence are now evident in imaging for all medical disciplines: reduced use of ionizing radiation, abandonment of invasive methods, real-time properties, visualization of functional parameters, digitalization and pooling of information, as well as interaction of user with image information. A wide variety of imaging methods is now available clinically for the study of head and neck diseases. However, only picture archiving and communication systems (PACS) can efficiently handle and integrate information coming from multiple imaging modalities, such as computed tomography, magnetic resonance imaging, positron emission tomography, digital subtraction angiography and digital radiography. Such systems also incorporate image workstations that the surgeon can use for preoperative planning and even perioperative assistance. Current PACS are reviewed, since their future use may change the operating theater and also change surgical strategies.

Diagnostic Imaging↗
PubMed1993

[Prevention of vascular complications in endonasal paranasal sinus surgery. Part II: Pre- and intraoperative imaging].

Computer-assisted surgery (CAS) is a new intraoperative localization system that is based on digital image generation devices. The system has been used in 189 cases of paranasal sinus procedures, employing computed tomography (CT) image data. Highly accurate imaging and localization of bony structures can be achieved in this way, although definition of vascular structures is limited by representation attributes of vessels in CT. Algorithms have now been developed for the use of magnetic resonance angiography (MRA) data with the system. CAS was used in six cases of endonasal surgery. Imaging helped substantially in all cases, but its application was limited by incomplete reflection of small vessels. In one case, intraoperative findings showed MRA-inherent inaccuracies. These might be avoided using correction programs and phantom selection (shimming) procedures in the future. Additionally, matching of different imaging modalities should improve intraoperative applications of CAS.

Algorithms↗
PubMed1993

Stereolithographic modelling for reconstructive head surgery.

Until now, bounds of model creation of medical objects had to be set because of the limited capabilities of available manufacturing equipment. Recently, stereolithography was developed as an alternative to current milling operations. In this process the surface of a photohardening liquid plastic compound is traced by a laser beam and hardened in layers. The models thus produced are extremely accurate and retain excellent detail. Specific implants can be designed and prepared as is illustrated in a case report. If tissue-compatible plastics are used, custom-made implants could soon be manufactured directly with the technique described.

Child↗
PubMed1993

Surgical or medical treatment of questionable peritonsillar abscess? The use of B-mode ultrasonography.

A prospective study was carried out to evaluate the sensitivity of sonography in the diagnosis of peritonsillar abscesses (quinsy). From 1986 to 1991 all cases of clinically doubtful peritonsillitis were subjected to B-Mode ultrasonography of the tonsils before tonsillectomy. 118 patients were examined. Sensitivity of the method in cases of clinically uncertain peritonsillar abscesses was 87%. The predictive value of the method was calculated to be 0.89; however only five false positive cases ("abscess" in ultrasound but no pus during surgery) were found. We therefore suggest that all patients suffering from questionable peritonsillitis should be examined by ultrasound. If abscess formation is suspected, surgical intervention is indicated. In all other cases I.V. antibiotics should be administered and control sonography should be carried out.

Adolescent↗
PubMed1993

Computer-assisted orbital surgery.

In orbital surgery, deep lesions must be operated on through extremely small approaches. We developed a method (Computer Assisted Surgery or CAS) designed to achieve safer and more precise surgery by providing highly accurate intraoperative information regarding the location of the surgical instrument. The device involved consists of a high-capacity computer that processes computed tomographic (CT) data in real time, connected to a mechanical measuring arm attached to the surgical instrument. From the CT data, the computer calculates a three-dimensional reconstruction and displays the tip of the instrument as a reticle in this model. Using the CAS system, the surgeon is continuously apprised of the precise position of the surgical instrument vis-a-vis all relevant anatomical structures. We have used CAS successfully in 21 cases of orbital surgery. We have found the system especially useful in dealing with deep-seated tumors, either for biopsy or surgery; in performing orbital and optic nerve decompression; in localizing deep-seated foreign bodies; and in all cases of impaired orientation due to severe bleeding, tumor-destroyed landmarks, or preoperated anatomy. Although the number of patients is too small to yield statistically significant data allowing a comparison of patient outcomes with and without using the system, we have just begun a large prospective clinical trial designed to provide such data.

Adolescent↗
PubMed1993

[How badly does the "normal-hearing" young man of 1992 hear in the high frequency range?].

In the course of a clinical study we examined young men believed to have normal hearing. Volunteers with a positive history for noise deafness were excluded from further study. Normal hearing was verified by pure-tone audiometry if the hearing loss did not exceed 15 dB for each test tone between 250 Hz and 8000 Hz. As this limit is far below normative threshold values (DIN ISO 7029) we expected to find a large number of otological normal subjects. Using pure-tone audiometry, ABR and noise exposure, we found that 65% of the young male volunteers (mean age 25 years) did not meet the criteria for audiologic normality. The pure-tone thresholds for these subjects were comparable to the expected levels of their fathers' generation.

Adult↗
PubMed1993

[A new procedure for removal of foreign bodies in the area of the head].

Identification and extraction of penetrating cranial foreign bodies can cause problems in some cases. Small fragments localized deep in the orbit or cerebrum can be especially hard to detect. Severe bleeding and traumatized anatomy can make orientation difficult. We used a new localizing device, computer-assisted surgery (CAS), to good effect in six such cases. CAS is a localizing technique designed to assist the head surgeon during surgery, providing real-time position information. The method is based upon a three-dimensional volume model of the patient's skull generated by preceding computed tomography imaging procedures (CT or MRI). Intraoperative correlation of a 3D-model and the patient's skull allows for real-time position display of a surgical instrument on the monitor screen. Thereby the surgeon is able to localize even small foreign bodies without extensive exploration. In the case of multiple foreign bodies the surgeon calls up a simple documentation facility recording which of the visible fragments have already been extracted. We successfully used the system for extraction of orbital foreign bodies in four and intracerebral foreign bodies in two cases. In a 4-year-old child with gunshot injury the bullet was located in the precentral region and was easily extracted with the CAS system. In a 21-year-old man 39 glass fragments were extracted from the left orbit. In a 36-year-old man a bone fragment was dislocated to the apex of the orbit directly under the optic nerve. Location and extraction were achieved without damage to the orbital structures with the help of the CAS system.

Adult↗
PubMed1992

[Artificial intelligence methods for support of medial patient education before surgical interventions in the region of the neck-nose-ear].

As a rule, curative operations require the patient's consent. Determined by the expansion of surgical possibilities, the kind and frequency of specific complications are subjected to constant changes. The physician is encouraged to explain therapeutic methods as well as the probability of complications within the patient's grasp. It has been investigated to what extent methods of artificial intelligence (AI) are suited for assisting the physician in this task. For this purpose, a comprehensive list of surgical complications as reported in research literature has been compiled. The list has been transferred into a hierarchical structure which can be depicted as a rule tree classified according to topographic aspects. In each otolaryngological operation, the reported complications can be classed with these rules. By employing an expert system (Fig. 1), the physician is capable of compiling an individualized document of agreement (Fig. 2) which serves as a basis for the explanatory talk with the patient.

Artificial Intelligence↗
PubMed1992

[Identification and removal of orbital foreign bodies using the CAS (Computer-Assisted-Surgery) system].

Identification and extraction of orbital foreign bodies can cause problems in special cases. Small, retroocular localized fragments can be hard to detect, severe bleeding and traumatically damaged anatomy can render orientation difficult. At the Department of Otolaryngology, Plastic Head and Neck Surgery of Aachen University Hospital we used the investigational new CAS (Computer-Assisted-Surgery) device in several such cases with good success. CAS is a new localizing technique designed to assist the head and neck surgeon during surgery providing real-time position information. The method is based upon a three dimensional volume model of the patient's skull generated by preceding computed tomography imaging procedures such as CT or MRI scan. Intraoperative correlation of 3D-model and the patient's skull allows for real-time position display of a surgical instrument on the monitor screen. Accuracy of the method has been experimentally determined to be within 1 mm. Thereby the surgeon is able to localize even small foreign bodies without extensive exploration. In the case of multiple foreign bodies the surgeon gets a simple documentation facility, which of the visible fragments have already been extracted. Medially placed foreign bodies could be removed via an endonasal approach. Encouraged by these results we recommend CAS for the extraction of orbital foreign bodies.

Accidents, Occupational↗