Tissue pO2 of human brain cortex--method, basic results and effects of pentoxifylline.

A polarographic multiwire surface electrode was used for measurement of local oxygen partial pressure (pO2) on human brain cortex during neurosurgical operations. The two major problems encountered in this application of the electrode involved sterility of the equipment and mounting of the electrode. The described method of sterilization does not alter the electrical properties of the electrode. A special mount was designed to allow free three-dimensional placement of the electrode without exerting pressure on the cortex. Basic results of this technique demonstrated that it is possible to distinguish different pO2 distribution patterns displayed in pO2 histograms for various types of brain tumors and edematous brain tissue. In patients with arteriovenous malformations (AVMs) of the brain, an increase of tissue pO2 in cortical areas adjacent to the AVM was the result of extirpation of the lesion. The effect of intravenously administered pentoxifylline was studied during extraintracranial bypass operations in patients with cerebrovascular disease. In 7 patients a consistent shift of the pO2 histograms to the right, i.e., to higher pO2 values, could be demonstrated. Mean pO2 values increased statistically significantly by 16 +/- 7 mmHg as early as ten minutes after infusion of pentoxifylline. The rapid improvement of tissue oxygenation of human brain cortex is thought to be the result of an improvement of microcirculation, for other parameters influencing tissue pO2 showed no significant alterations if any.

Surgical anatomy of the singular nerve.

Rare cases of chronic persistent positional vertigo do not respond to physiotherapy. For the treatment of these cases Gacek suggested singular nerve neurectomy as a new surgical procedure. The aim of the present study was to investigate the surgical anatomy of the singular nerve in order to evaluate the exact topography. In 25 cadaver temporal bones the posterior ampullary ("singular") nerve was prepared. The topographical correlation between singular nerve, posterior semicircular canal, and the round window membrane was evaluated. The average length of the nerve was 4.2 mm, its diameter 0.6 mm. The shortest distance between singular nerve and round window membrane was 0.7 mm in average, the nerve could be detected at a depth of 1.3 mm. The transtympanal access was impossible in 7 of 25 cases either because of its close relation to the round window or its direct course towards the ampulla. In only 5 of 25 cases was the nerve located sufficiently inferior in the round window niche for neurectomy. Thus, transtympanal singular nerve neurectomy can be performed only in selected cases. The presented data are helpful for preoperative and intraoperative decisions.

Neue Aspekte zur Mechanik der Tuba auditiva.

The aim of the present article is to describe the mechanical components of the auditory tube and the role of these components in auditory tube function. Particular attention will be given to those aspects which have not been sufficiently dealt with in the past, such as the role of the isthmus region, the function of the lateral mucosal folds, the significance of the surfactant proteins and the pathophysiology of the patulous auditory tube. Special attention is given to the tensor veli palatini muscle and its physiology. Because of its isometric contraction, the function of this muscle depends on so-called hypomochlia changing the direction of its force. In the context of this article, the three hypomochlia involved are the pterygoid hamulus, Ostmann's fatty tissue and the medial pterygoid muscle.The so-called "Eppendorf-maneuver" is depicted for the first time.

Planning and rehearsal of surgical interventions in the volume model.

Visualization of 3D medical data is routinely used in a wide range of applications. However, for the planning and rehearsal of surgical interventions more sophisticated techniques for interaction have to be developed. The realistic specification and visualization of free form cuts is needed to allow the 'look and feel' close to a real dissection. The problem here is, since these cuts are not represented by intensity changes, that the gray-level-gradient-method can not be used for the estimation of surface normals. In addition, the interactive repositioning of dissected fragments has to be simulated. We have developed an extended ray-casting algorithm for visualization of object motion in the volume model. We implemented new methods for the representation, modeling and high quality rendering (subvoxel resolution) of arbitrarily shaped cut regions within the volume model. The representation is done using a dynamic data structure. This way, all operations can easily be reversed and the original object information is preserved. The modeling of cut surfaces is done in an independent data volume where the partial-volume-effect, which is the prerequisite for the gray-level-gradient method, is calculated as it would be generated by an imaging system. This way, the localization of cut surfaces at subvoxel resolution and an accurate estimation of the surface normals is achieved. The key point here is to detect if a cut surface really truncates an object or if the object has not been affected by a cutting operation. We will present an new method, called adaptive sampling which allows to determine the situation by the generation of additional sample points (when necessary) during the ray casting process. The described techniques provides the basis for simulation of surgical interventions in the voxel-model which could not be achieved with any surface-based method. We present a system for simulation and rehearsal of otosurgical approaches, where we implemented a drill-like tool with which the student lays off the route to the operating area. The key point is to not injure structures of risk such as the facial nerve. For applications like the simulation of craniofacial surgery we developed a gradual cutting tool ("virtual scalpel").

Audiometric characteristics of two Dutch families with non-ocular Stickler syndrome (COL11A2).

OBJECTIVE: To evaluate hearing impairment and cochlear function in non-ocular Stickler syndrome. STUDY DESIGN: Multifamily study. PATIENTS & METHODS: Ten patients from two different families with non-ocular Stickler syndrome (Stickler syndrome type 3) were included. Six members of the first family and four members of the second family participated in this study. Otorhinolaryngologic examinations were performed. Pure-tone and speech audiograms were obtained. Longitudinal analysis was performed. Psychophysical measurements, including loudness scaling, gap detection, difference limen for frequency and speech perception in noise were administered to assess cochlear function at a deeper level. RESULTS: Affected individuals in the first family were carriers of a heterozygous splice donor mutation in the COL11A2 gene. Affected individuals in the second family were carriers of a novel heterozygous missense mutation in COL11A2. Both families showed bilateral, non-progressive hearing impairment with childhood onset. The severity of the hearing impairment exhibited inter- and intrafamilial variability and was mostly mild to moderate. The results of the psychophysical measurements were similar to those previously published for DFNA8/12 (TECTA) and DFNA13 (COL11A2) patients and thus consistent with an intra-cochlear conductive hearing impairment. This is in line with the theory that mutations in COL11A2 affect tectorial membrane function. CONCLUSION: Hearing impairment in non-ocular Stickler syndrome is characterized by non-progressive hearing loss, present since childhood, and mostly mild to moderate in severity. Psychophysical measurements in non-ocular Stickler patients were suggestive of intra-cochlear conductive hearing impairment.

Individual models for virtual bone drilling in mastoid surgery.

Segmented training cases for virtual simulation of bone-drilling interventions in middle ear surgery have proven to be helpful in learning about surgical anatomy of the temporal bone. The anatomy of the mastoid shows a high degree of variability, however, and the aim of this study was to evaluate whether individual virtual models could be created within an affordable timeframe, and to what extend they reflected natural individual anatomy during virtual mastoid surgery. Automatic segmentation schemes were used, and these reduced the time required to create individual models on the basis of DICOM CT scans to less than 5 minutes. Models based on CT data with a slice distance of 0.4 mm or better were found to provide excellent handling, an acceptable depiction of mastoidal organs, and a helpful impression of the individual surgical situation. Although landmarks are still more easily detected in real mastoids, virtual drilling of individual models makes the 3D estimation of specific anatomy more effective than estimations based on interpretation of CT scans alone.

Chemokine CXCL13 is overexpressed in the tumour tissue and in the peripheral blood of breast cancer patients.

The abilities of chemokines in orchestrating cellular migration are utilised by different (patho-)biological networks including malignancies. However, except for CXCR4/CXCL12, little is known about the relation between tumour-related chemokine expression and the development and progression of solid tumours like breast cancer. In this study, microarray analyses revealed the overexpression of chemokine CXCL13 in breast cancer specimens. This finding was confirmed by real-time polymerase chain reaction in a larger set of samples (n = 34) and cell lines, and was validated on the protein level performing Western blot, ELISA, and immunohistochemistry. Levels of CXCR5, the receptor for CXCL13, were low in malignant and healthy breast tissues, and surface expression was not detected in vitro. However, we observed a strong (P = 0.0004) correlation between the expressions of CXCL13 and CXCR5 in breast cancer tissues, indicating a biologically relevant role of CXCR5 in vivo. Finally, we detected significantly elevated serum concentrations of CXCL13 in patients with metastatic disease (n = 54) as compared with controls (n = 44) and disease-free patients (n = 48). In conclusion, CXCL13 is overexpressed within breast cancer tissues, and increased serum levels of this cytokine can be found in breast cancer patients with metastatic disease pointing to a role of CXCL13 in the progression of breast cancer, suggesting that CXCL13 might serve as a useful therapeutic target and/or diagnostic marker in this malignancy.

Restoration of hearing by hearing aids: conventional hearing aids - implantable hearing aids - cochlear implants - auditory brainstem implants.

Aim of this report is to explain the current concept of hearing restoration using hearing aids. At present the main issues of conventional hearing aids are the relative benefits of analogue versus digital devices and different strategies for the improvement of hearing in noise. Implantable hearing aids provide a better sound quality and less distortion. The lack of directional microphones is the major disadvantage of the partially implantable hearing aids commercially available. Two different clinical studies about fully implantable hearing aids have been started in 2004. One of the most-promising developments seems to be the electric-acoustic stimulation.

[Histomorphological study of experimentally induced canalolithiasis]. / Histomorphologische Untersuchung bei experimentell induzierter Kanalolithiasis.

Free otoconia in the posterior semicircular canal (pSCC) are regarded as the main reason for benign paroxysmal positional vertigo. We investigated the distribution of otoconia in the membranous labyrinth of guinea pigs (n = 34) after a defined rotatory/angular kinetic acceleration. The angular kinetic energy of the rotatory experiment produced a dislocation of the otoconia and sometimes of the complete gelatinous otolithic membrane of the utricular and saccular macula. The otoconia could be observed in all three semicircular canals but predominated in the dark cell areas of the utricular side of the lateral SCC. A total obstruction of the semicircular canal could never be seen. Close to the lateral crista, perilymphatic hemorrhage could frequently be observed. The saccular otoconia were located in the amalgamation between endolymphatic membrane and saccule. The results of this histological study can form the basis for different theories about the genesis of canalolithiasis and cupulolithiasis and the vertigo which accompanies them.

[G-DRG System 2005. Analysis and evaluation of significant changes from the viewpoint of HNO medical science]. / G-DRG-System 2005. Analyse und Bewertung wesentlicher Anderungen aus Sicht der HNO-Heilkunde.

With the release of the new Global Case Agreement by Self Administration in Public Health on the 16 September 2004, the adjustment of the G-DRG System for the year 2005 was completed. Otorhinolaryngology, and head and neck surgery face several changes in the fields of diagnosis and procedural coding (ICD-10-GM 2005, OPS-301 2005), G-DRG case allocation, and extra reimbursements for special interventions. Despite some considerable improvements, substantial problems remain unsolved. This paper presents and comments on the key points of the G-DRG System for 2005 for otorhinolaryngology, and head and neck surgery.

[Influence of botulinum toxin on myogenous facial pain]. / Beeinflussung muskulärer Gesichtsschmerzen durch Botulinumtoxin A.

OBJECTIVE: Can chronic pain of the masticatory muscles be positively affected by low dose injection of botulinum toxin (BTX-A)? METHODS: Twenty patients suffering chronic myofacial pain were questioned and examined after injection of 25-50 U Dysport into the affected muscles over a period of 8 weeks. RESULTS: Four weeks after injection of BTX-A patients reported a significant reduction of pain (p <0.001, paired t-test. Power of performed test with alpha 0.050:1.000). Then the pain remained constant over the next 4 weeks. Concurrently a significant increase of mandubular range of movement was observed (p <0,05, Wilcoxon signed rank test). CONCLUSIONS: Even though lacking placebo control the findings suggest that patients suffering chronic myofacial pain may benefit from injection of low dose BTX-A into the affected muscles.

[Muscular compliance of the auditory tube]. / Zur muskulären Compliance der Tuba auditiva.

BACKGROUND: The simultaneous electromyographical assessment of innervation patterns of the mylohyoid and the tensor veli palatini muscle is introduced as a new technique for the examination of the auditory tube function. PATIENTS AND METHODS: Clinical studies were performed on 30 healthy volunteers and 50 patients suffering from chronic tubotympanic mucositis and cholesteatoma. Concentric needle electrodes were advanced into the tensor veli palatini muscle through the palate. The mylohyoid muscle was examined using surface electrodes. RESULTS: Innervation patterns of the tensor veli palatini muscle in volunteers were limited to the time interval of the mylohyoid innervation pattern only, i.e., the oral and pharyngeal phases of swallowing. In 14 of the chronic otitis patients these tensor muscle innervation patterns were found outside this interval. CONCLUSION: This observation provides a new pathophysiological explanation for the clinical concept of a relative closing failure of the auditory tube. These results emphasize the significance of coordination in muscular compliance of the tube.

["Crown-cork tympanoplasty"--a method for complete reconstruction of the tympanic membrane]. / Die "Kronenkorkentympanoplastik"--eine Methode zur Trommelfelltotalrekonstruktion.

The crowncorktympanoplasty is a technique for the total reconstruction of the tympanic membrane, recommended in cases of ear malformation, blunting-phenomena and total deficiency of the membrane caused by chronic otitis media. Autologous tragal composite graft is used for the myringoplasty. While the cartilage faces to the middle ear cavity, the overflapping perichondrium is layed on the bony meatal wall in the manner of a crowncork. 10 cases performed in the last two years are reported. In each one an intact tympanic membrane could be reached. In average, the ear bone gap could be reduced for 18.5, 17.5, 16.5 and 13.5 dB in the frequencies of 500, 1000, 2000 and 4000 Hz.

[Diseases of the petrous bone--demands made on radiologic diagnosis from the otosurgical point of view]. / Erkrankungen des Felsenbeins--Forderungen an die radiologische Diagnostik aus otochirurgischer Sicht.

Advances in microsurgical techniques in otosurgery as well as further developments in imaging methods enable the surgeon to perform procedures at the petrous bone that are as radical as they can contribute to retaining the function. The present study aims at explaining by means of case reports the specific otosurgical problems in typical diseases of the otobase and at presenting the ranking of the individual imaging methods from the surgeon's point of view. For example, special features in the preoperative diagnosis of glomus tumours, acoustic neurinomas, Ménière's disease, cholesteatomas and so-called petrous bone tip processes are pointed out. A special aspect of radiological and surgical collaboration is seen in highly vascularised tumours of the otobase in respect of the possibilities offered by interventional angiography. The importance of MR-tomography in preoperative diagnostics is assessed with some reservation because this does not show up surgically relevant landmarks.

[Significance of ultrahigh resolution computed tomography in the preoperative diagnosis of Menière's disease]. / Zum Stellenwert der ultrahochauflösenden Computertomographie in der präoperativen Diagnostik des M. Menière.

By means of ultrahigh resolution computed tomography imaging of very small labyrinthine structures such as the vestibular aqueduct and the rima sacci endolymphatici is possible. Aim of the present study was to demonstrate the significance of ultrahigh resolution CT in the preoperative management of Menière's disease. The study was carried out on 16 patients who underwent endolymphatic mastoidal shunt operation. Postoperative imaging and clinical findings were compared. By means of ultrahigh resolution technique the vestibular aqueduct could be examined in all of our patients. Two CT-findings of atresia of the external aperture were confirmed intraoperatively. Preoperative ultrahigh resolution computed tomography is a reliable method to demonstrate the distinct variability of the oto-surgical landmarks for endolymphatic shunt operation. There is no reliable correlation between the width, shape and bony contrast of the vestibular aqueduct and the postoperative outcome. Thus in our opinion preoperative ultrahigh resolution computed tomography is mandatory for the preoperative management of Menière's disease.

[3D reconstruction by high resolution MR tomography of the inner ear]. / Die 3D-Darstellung hochauflösender MR-Tomographien des Innenohres.

By means of modern 3D-visualization systems it is possible to render detailed reconstructions of very small morphological structures such as the inner ear. Aim of the present study was to demonstrate the imaging quality of a new 3D-segmentation program developed in the University of Hamburg. The investigation was carried out on a high-resolution MR-tomography of the author's labyrinth and facial nerve. The images were obtained with a fast-field-echo technique using a surface coil. 32 axial slices of 1.0 mm thickness were used for reconstruction. Thus it was possible to completely visualize cochlea, semicircular canals and facial nerve. Especially the filiform substructures of the inner ear could reliably be reconstructed. So the content of information of the MR-investigation could be increased by the 3D-technique applied.

[Value of duplex ultrasound in diagnosis of parotid tumors]. / Stellenwert der Duplexsonographie bei der Diagnostik von Parotistumoren.

BACKGROUND: The sensitivity of diagnostic imaging of processes in the parotid gland has been increased by improved spatial resolution, yet specificity remains unchanged. The purpose of this study was to determine whether the low-flow color duplex technique alters the specificity of B-mode ultrasonography. PATIENTS AND METHODS: Forty-one patients with tumors of the parotid gland were examined by color duplex echography as well as histologically. Twenty-eight of the 41 patients had benign tumors and 13 had malignant disease. In 17 of 41 patients, color duplex ultrasonography failed to detect any vascularization within the tumor. Histopathological examination showed that 3 of these 17 tumors were malignant and 14 of 17 were benign. Intranodal vascularization was detected in 24 cases. Ten of these patients were found to have malignant tumors of the parotid gland; 14 had benign parotid tumors. RESULTS: Our present findings show that marked intratumoral vascularization especially appears in malignant tumors. In contrast to lymph nodes, the location and texture of intranodal blood vessels do not provide information about the nature of the neoplasm. CONCLUSIONS: Low flow duplex ultrasonography does not increase the specificity of preoperative examination in tumors of the parotid gland.

[Stereoscopic simulation of ear surgery intervention with a novel 3D computer models]. / Die stereoskopische Simulation ohrchirurgischer Eingriffe an einem neuartigen 3D-Computermodell.

INTRODUCTION: The presentation of the surgical anatomy of the temporal bone by standard anatomical figures is not suitable for otosurgical training. For the comprehension of its complex morphology temporal bone drilling is inalienable. Aim of the present cooperation was to gain an interactive real-3D program for the simulation of specific laterobasal surgical approaches. METHODS: The program was derived from a standard horizontal section of a human temporal bone using a Siemens Somatom Plus 4 Tomograph. The slice thickness was 1 mm, the image matrix was 512. The Voxel-Man-system was used to built up the application for unix workstations. RESULTS: Each step of a surgical approach to the temporal bone can be performed by the present computer model. Calculation in a stereo mode even allows spatial 3D-perception when using red/green glasses. CONCLUSIONS: This program is a novel tool to simulate critical aspects of otosurgical procedures on a computer. Up to now the lack of tactile and kinesthetic information does not allow to renounce individual temporal bone drilling.