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C Matthies

Publications and source records attributed to C Matthies.

At least 19 recordsLinked to original sources
PubMed2002

Vestibular schwannomas and auditory function: options in large T3 and T4 tumors?

OBJECTIVE: While hearing preservation has become an accepted treatment goal, there are still major doubts whether and to what extent this aim is feasible in large tumors that cover the auditory nerve and involve the brainstem. METHODS: One thousand eight hundred (1,800) vestibular schwannomas (VS) were operated on at Nordstadt Neurosurgical Department from 1978 to 1999 by the senior surgeon (MS). There were 1,800 tumors in 1,750 patients, 1,605 patients had unilateral tumors, 145 patients had neurofibromatosis type 2 with bilateral tumors, 195 of which were treated surgically in our unit. Preservation of the cochlear nerve was attempted when ever possible. The audiometric data are analyzed by Hannover Classification System graded in steps of 20 dB by audiometry and in steps of 10% to 30% by speech discrimination. Those data were set into relation with the Hannover tumor extension grading T1 to T4. RESULTS: Overall preservation rate was 40% with considerable differences, though, depending on the preoperative hearing quality and the tumor extension. Best results were obtained for intrameatal tumors (T1) with 56% and small intra-extrameatal tumors (T2) with 57% preservation rate. While preservation rate was at 44% in medium-sized tumors (T3), it was at 20% for T4 tumors with brainstem compression or even dislocation. However, satisfactory chances were encountered in cases with normal or good preoperative hearing, on average 54%, specifically 71% in T1, 69% in T2, 58% in T3 and 29% in T4. Regarding the quality of the preserved hearing, up to one third of cases in T1 and T2 may retain their preoperative hearing level, while this ranges around 20% for T3 and 10% to 14% in T4 tumors. DISCUSSION: For long, hearing preservation in medium sized or large tumors has not received any attention because of the presumed lack of realistic chances and the expected bad quality. Obviously, hearing preservation may be achieved in relevant numbers and at satisfactory quality levels. This aspects appears important to be addressed further in view of the fact that over 70% of tumors are presented for surgery at T3 or T4 extensions. CONCLUSION: The summit of hearing preservation has not been reached as improvements are still achieved even in most difficult conditions.

Cerebellopontine Angle↗
PubMed2001

Resting regional cerebral glucose metabolism in advanced Parkinson's disease studied in the off and on conditions with [(18)F]FDG-PET.

Studies of resting regional cerebral glucose consumption (rCMRGlc) in nondemented patients with Parkinson's disease (PD) have produced conflicting results, reporting both reduced and normal metabolism in advanced disease and reduced or normal metabolism after dopaminergic therapy. To investigate these issues, [(18)F]fluorodeoxyglucose (FDG) positron emission tomography (PET) was performed in 11 nondemented PD patients with advanced disease and 10 age-matched controls. PD patients were studied after withdrawal of all dopaminergic medication to produce a practically defined off condition, and a second time 1 hour after levodopa, resulting in a clinical on state. Dynamic PET scans and simultaneous arterialised venous blood samples of [(18)F] activity were obtained. A graphical approach was used to generate parametric images of rCMRGlc and statistical parametric mapping to localise significant metabolic changes in PD. Compared with controls, global rCMRGlc was reduced in the on but not in the off condition in PD. In both states, significant regional reductions of glucose uptake were found in the parietal, frontal, temporal cortex, and caudate nucleus. Reductions correlated with the severity of disability in frontal and temporal cortex. Direct comparison between on and off conditions revealed relatively greater reductions of uptake in the ventral/orbital frontal cortex and the thalamus during on. Results suggest that cortical and caudate hypometabolism are common in advanced PD and that caution is mandatory if [(18)F]FDG PET is being used to differentiate advanced PD from dementia and progressive supranuclear palsy where similar reductions are seen. Furthermore, in PD, administration of levodopa is associated with further hypometabolism in orbitofrontal cortex; an area known to be relevant for reversal learning where performance is typically impaired after dopaminergic treatment.

Adult↗
PubMed2001

Trigeminal root recording in normal trigeminal function.

Despite many investigations on the detection of trigeminal evoked potentials (TEP), there is still no consensus on a technique or interpretation of its components. In order to obtain clear TEP waveforms and analyze the origin of early components, we recorded TEP by the conventional far-field technique at the ipsilateral auricula as well as by near-field technique with a bipolar electrode at the trigeminal root just distal to the entry zone of its root. Trigeminal recordings were performed in nine patients with intrameatal vestibular schwannomas and in three with trigeminal neuralgia without trigeminal nerve deficits. In near-field recording at the trigeminal root, a triphasic response was recorded, with the first component occurring at 3.16 ms, 2.98 ms, and 4.16 ms following supraorbital, infraorbital, and mandibular nerve stimulation, respectively. Using conventional farfield TEP, the first component recorded at the trigeminal root occurred later than the first component in all other recordings. This suggests that the N2.0 component of far-field TEP is of extra-axial origin and the N5 component is of brainstem origin. The N13.0 component may be of cortical origin. We conclude that the N5.0 component and N5.0-N13.0 interpeak latency may be used as electrophysiological parameters of brainstem function during posterior fossa surgery.

Electric Stimulation↗
PubMed2001

Auditory brainstem implant: part I. Auditory performance and its evolution over time.

OBJECTIVE: Evaluation of auditory performance and its evolution over time in patients with the auditory brainstem implant. STUDY DESIGN: Prospective study. SETTING: Tertiary referral center. PATIENTS AND METHODS: Between May 1996 and April 2000, 14 patients with neurofibromatosis type 2 underwent implantation with a multichannel auditory brainstem implant. Auditory performance data were obtained in 13 patients who had used their device on a regular daily basis for 1 to 41 months (average 19 months). Hearing evaluation was based on the results of four tests (vowel confusion, consonant confusion, Freiburger numbers, and speech-tracking test), which were performed with and without lip-reading at regular intervals after device activation. RESULTS: 12 patients received auditory sensation through the auditory brainstem implant immediately after device activation. In one patient, because of postoperative electrode migration, device activation was not successful. In this case, after the electrode array was repositioned, activation was successful. The results of the audiovisual mode 2 weeks after device activation revealed a lip-reading enhancement above the chance level in about 50% of the patients in the vowel confusion and speech-tracking tests and in 70% of the patients in the consonant confusion test. Lip-reading enhancement improved within the first 6 months and then entered a plateau phase, which was more prominent in the monosyllabic vowel and consonant tests. In the auditory alone mode, more than half of the patients showed their first positive result in the vowel test 3 months after device activation, but it took about 6 months until half of the patients revealed a result above the chance level in the consonant and Freiburger numbers tests. Open set speech recognition in the auditory alone mode (in the speech-tracking test) was not common and happened relatively late (within 1 year or later). DISCUSSION AND CONCLUSION: Although auditory sensation appeared immediately after device activation, a period of 6 months was necessary for relearning and adaptation of the central auditory system to the altered form of auditory information presented by the auditory brainstem implant.

Adult↗
PubMed2001

Clostridium uliginosum sp. nov., a novel acid-tolerant, anaerobic bacterium with connecting filaments.

An anaerobic, acid-tolerant bacterium, CK55T, was isolated from an acidic forest bog. Cells of CK55T stained Gram-negative but did not have an outer membrane. Cells were spore-forming, motile rods with peritrichous flagella, formed chains or aggregates and were linked by connecting filaments that were composed of a core and outer sheath. Cellobiose, glucose, xylose, mannose, mannitol, sucrose and peptone supported growth. Arabinose, lactose, raffinose, H2/CO2, CO/CO2, vanillate, Casamino acids and various purines and pyrimidines did not support growth. Growth on carbohydrates yielded acetate, butyrate, lactate, formate and H2 as end-products. Growth was observed at pH 4.0-9.0, with an optimum at pH 6.5, and at 10-30 degrees C, with an optimum at 20-25 degrees C. At 20 degrees C, doubling times were 4 and 6 h at pH 6.5 and 4.0, respectively. Hydrogenase activity in cell-free extracts was 12 U (mg protein)-1. CK55T did not: (i) contain detectable levels of CO, formate, lactate dehydrogenases or cytochromes; (ii) carry out dissimilatory reduction of nitrate or sulfate; or (iii) produce methane. Thus, CK55T was characterized as a non-acetogenic, fermentative chemo-organotroph. The G+C content of CK55T was 28.0 mol%. CK55T was phylogenetically most closely related to Clostridium botulinum (types B, E and F), Clostridium acetobutylicum and other saccharolytic clostridia; the 16S rRNA gene sequence similarity values to the nearest relatives of CK55T were approximately 97%. Based on morphological, physiological and phylogenetic properties of CK55T, it is proposed that CK55T be termed Clostridium uliginosum sp. nov. (= DSM 12992T = ATCC BAA-53T).

Anaerobiosis↗
PubMed2001

Surgical management of brainstem cavernomas.

OBJECT: A careful retrospective analysis of 36 cases was performed to evaluate the pre- and postoperative rates of morbidity that occur in patients with brainstem cavernous angiomas. METHODS: The authors evaluated immediate postoperative and follow-up outcomes with regard to clinical findings, the incidence of preoperative hemorrhage(s), location and size of the lesions, and the timing of the surgical procedure after the last hemorrhagic event. Specifically. the following parameters were analyzed: 1) number of hemorrhages; 2) the precise brainstem location (pontomesencephalic, pons, and medulla oblongata); 3) pre- and postoperative cranial nerve status; 4) pre- and postoperative motor and sensory deficits; 5) size (volume) of the lesions; and 6) pre- and postoperative Karnofsky Performance Scale (KPS) scores. Multiple hemorrhages were observed in 16 patients, particularly in those with pontomesencephalic cavernous angiomas (75%). The mean preoperative KPS score was 70.3 +/- 16.3 (+/- standard deviation). Twenty-six patients (72.2%) presented with cranial nerve impairment, 13 (36.1%) with motor deficits, and 17 (47.2%) with sensory disturbance. Volume of the lesions ranged from 0.18 to 18.18 cm3 (mean 4.75 cm3). Postoperative complications included new cranial nerve deficits in 17 patients, motor deficits in three, and new sensory disturbances in 12 patients. In a mean follow-up period of 21.5 months, KPS scores were 80 to 100 in 22 patients. Timing of surgery (posthemorrhage) and multiple hemorrhages did not influence the long-term results. Higher preoperative KPS scores and smaller-volume lesions, however, were factors associated with a better final outcome (p < 0.05). Major morbidity was related mainly to preoperative status and less to surgical treatment. The incidence of new postoperative cranial nerve deficits was clearly lower than that demonstrated preoperatively because of the brainstem hemorrhages. CONCLUSIONS: Based on these findings, resection of brainstem cavernomas is the treatment of choice in the majority of these cases because of the high incidence of morbidity related to one or often several brainstem hemorrhages.

Adolescent↗
PubMed2001

Far-field responses to stimulation of the cochlear nucleus by microsurgically placed penetrating and surface electrodes in the cat.

OBJECT: A new generation of penetrating electrodes for auditory brainstem implants is on the verge of being introduced into clinical practice. This study was designed to compare electrically evoked auditory brainstem responses (EABRs) to stimulation of the cochlear nucleus (CN) by microsurgically implanted surface electrodes and insertion electrodes (INSELs) with stimulation areas of identical size. METHODS: Via a lateral suboccipital approach, arrays of surface and penetrating microelectrodes with geometric stimulation areas measuring 4,417 microm2 (diameter 75 microm) were placed over and inserted into the CN in 10 adult cats. After recording the auditory brainstem response (ABR) at the mastoid process, the CN, and the level of the inferior colliculus, EABRs to stimulation of the CN were recorded using biphasic, charge-balanced stimuli with phase durations of 80 microsec, 160 microsec, and 240 microsec at a repetition rate of 22.3 Hz. Waveform, threshold, maximum amplitude, and the dynamic range of the responses were compared for surface and penetrating electrodes. The EABR waveforms that appeared for both types of stimulation resembled each other closely. The mean impedance was slightly lower (30 +/- 3.4 kohm compared with 31.7 +/- 4.5 kohm, at 10 kHz), but the mean EABR threshold was significantly higher (51.8 microA compared with 40.5 microA, t = 3.5, p = 0.002) for surface electrode arrays as opposed to penetrating electrode arrays. Due to lower saturation levels of the INSEL array, dynamic ranges were almost identical between the two types of stimulation. Sectioning of the eighth cranial nerve did not abolish EABRs. CONCLUSIONS: Microsurgical insertion of electrodes into the CN complex may be guided and monitored using techniques similar to those applied for implantation of surface electrodes. Lower thresholds and almost equivalent dynamic ranges indicate that a more direct access to secondary auditory neurons is achieved using penetrating electrodes.

Animals↗
PubMed2000

Acoustic evoked response following transection of the eighth nerve in the rat.

OBJECT: The auditory brainstem response (ABR) is the most widely used means of intra-operative monitoring of the integrity of the auditory nerve and brainstem pathways during surgery in the cerebellopontine angle (CPA). Reliability of this and other electrophysiological techniques has been questioned because of persisting potentials in direct nerve recordings despite complete eighth nerve section. The study was designed to assess the extent to which an acoustic evoked response persists after the cochlear nerve is lesioned in the CPA of the adult rat. METHODS: The eighth nerve was exposed microsurgically via a lateral suboccipital approach without damage to surrounding structures. The auditory brainstem response to monaurally presented click stimuli was recorded using needle electrodes and a bandpass of 10 to 5000 Hz. FINDINGS: Complete sharp sectioning of the nerve in the CPA resulted in immediate disappearance of brainstem-generated potentials but persistence of a large primary, vertex-positive wave in all but one case. This response was also abolished in recordings three days later and after emptying the inner ear canal. Provided that the cochlea remained intact, two weeks later a single, vertex-positive potential in the latency range of wave Ia of the ABR reappeared, reaching its peak amplitude six weeks after sectioning of the nerve. CONCLUSIONS: The short-latency electrical potential recorded following damage of the eighth nerve in the cerebellopontine angle can be mistaken for an indication that nerve function is still preserved. The evoked injury potential is probably the major contributor to this potential that resembles wave I of the ABR. Monitoring of functional auditory integrity must neither be limited to early components of the ABR, nor to the electrocochleogram (EcoG) and the peripheral compound nerve action potential (CNAP), respectively.

Action Potentials↗
PubMed2000

Subarachnoid fat dissemination after resection of a cerebellopontine angle dysontogenic cyst: case report and review of the literature.

OBJECTIVE AND IMPORTANCE: This case report illustrates the clinical and radiological relevance of extensive intracranial subarachnoid and ventricular dissemination in dysontogenic (dermoid) tumors. CLINICAL PRESENTATION: We describe a patient with a cerebellopontine angle dysontogenic tumor. Postoperatively, the cyst disseminated fat particles extensively into the subarachnoid space. Magnetic resonance imaging (MRI) studies revealed continuous dispersion of the fat particles into the cerebral cisterns, subarachnoid space, and ventricles. INTERVENTION: Eight years of clinical and MRI follow-up demonstrated neither neurological deterioration in the patient nor growth of the multiple lesions. CONCLUSION: Intracranial subarachnoid dissemination of fat material may occur during the preoperative or postoperative course of dermoid and epidermoid cysts. Aseptic meningitis or other complications such as hydrocephalus, seizures, or cranial nerve deficits also may occur owing to spillage of intracranial cyst contents into the subarachnoid space. MRI can detect the presence of fat drops that may adhere to the surrounding structures or migrate with the cerebrospinal fluid flow. Intracranial disseminated fat particles can remain silent without radiological or neurological change, justifying a wait-and-see approach. During long-term postoperative follow-up, however, regular MRI studies and clinical examinations are necessary to avoid potential complications.

Adult↗
PubMed2000

Pelospora glutarica gen. nov., sp. nov., a glutarate-fermenting, strictly anaerobic, spore-forming bacterium.

The strictly anaerobic, Gram-negative, spore-forming bacterium strain WoGl3T had been enriched and isolated in mineral medium with glutarate as the sole source of energy and organic carbon. Glutarate was fermented to a mixture of butyrate, isobutyrate, CO2 and small amounts of acetate. Strain WoGl3T grew only with the dicarboxylates glutarate, methylsuccinate and succinate. 16S rDNA sequence analysis revealed an affiliation of strain WoGl3T to the family Syntrophomonadaceae. This monophyletic group is comprised of strain WoGl3T and the genera Syntrophomonas, Syntrophospora and Thermosyntropha, within the phylum of Gram-positive bacteria with a low DNA G + C content. Overall intra-group 16S rRNA sequence similarities of 89.2-93.9% document a separate phylogenetic status for strain WoGl3T. Strain WoGl3T (= DSM 6652T) is described as the type strain of a new species within a new genus, Pelospora glutarica gen. nov., sp. nov.

DNA, Bacterial↗
PubMed2000

Clostridium akagii sp. nov. and Clostridium acidisoli sp. nov.: acid-tolerant, N2-fixing clostridia isolated from acidic forest soil and litter.

Two anaerobic acid-tolerant bacteria, CK58T and CK74T, were isolated from acidic beech litter and acidic peat-bog soil, respectively. Both bacteria were spore-forming, motile rods with peritrichous flagella. The capacity to sporulate decreased with prolonged cultivation. Cells of CK58T formed chains or aggregates and were linked by a connecting filament that consisted of a core and a surrounding sheath. Cellobiose, glucose, xylose, arabinose, maltose, mannose and salicin supported growth of CK58T. These substrates, as well as mannitol, lactose, sucrose, glycerol, melezitose, raffinose and rhamnose, supported growth of CK74T. Sorbitol, trehalose, H2/CO2, CO/CO2, vanillate, Casamino acids, peptone, and various purines and pyrimidines did not support the growth of either organism. Growth of CK58T and CK74T on glucose yielded butyrate, lactate, acetate, formate, H2 and CO2 as end products. Growth of CK58T and CK74T was observed at pH 3.7-7.1 and 3.6-6.9, respectively. CK58T and CK74T grew in nitrogen-free medium at pH 3.7 under an N2 atmosphere and reduced acetylene at rates approximating 1 nmol min-1 (mg protein)-1. CK58T and CK74T did not contain carbon monoxide dehydrogenase or cytochromes, produce methane, or dissimilate nitrate or sulfate. Thus, CK58T and CK74T were characterized as nonacetogenic, N2-fixing, fermentative chemo-organotrophs. The G + C contents of CK58T and CK74T were 31.4 and 30.7 mol%, respectively. CK58T and CK74T were phylogenetically most closely related to Clostridium pasteurianum. The 16S rRNA gene sequence similarity values of CK58T and CK74T to C. pasteurianum and each other did not exceed 96.5%, and it is proposed that strains CK58T and CK74T be named Clostridium akagii CK58T (DSM 12554T) and Clostridium acidisoli CK74T (DSM 12555T), respectively. These results suggest that previously uncharacterized clostridial species reside and might fix N2 in the annoxic microzones of acidic forest soil and litter.

Anaerobiosis↗
PubMed2000

Anaerovorax odorimutans gen. nov., sp. nov., a putrescine-fermenting, strictly anaerobic bacterium.

The strictly anaerobic, gram-positive, non-spore-forming bacterium strain NorPut1T ferments putrescine to acetate, butyrate, molecular hydrogen and ammonia. It also utilizes 4-aminobutyrate and 4-hydroxybutyrate as growth substrates. Comparative 16S rDNA sequence analysis confirmed a phylogenetic affiliation of this strain to the phylum of gram-positive bacteria with low DNA G+C content. Together with its closest relative, 'Clostridium aminobutyricum' (DSM 2634), and several Eubacterium species, strain NorPut1T represents a well-defined monophyletic group. Moderate overall 16S rRNA sequence similarities (< 91%) were found for the NorPut1T/'Clostridium aminobutyricum' pair and several Eubacterium species. The type species, Eubacterium limosum, is not a member of the group and, together with Eubacterium barkeri and Pseudoramibacter alactolyticus, represents a distant phylogentic cluster. Therefore, a new genus, Anaerovorax, is proposed as harbouring strain NorPut1T (= DSM 5092T), which is described as a new species, i.e. Anaerovorax odorimutans.

Acetates↗
PubMed2000

Auditory brainstem implants: current neurosurgical experiences and perspective.

The objective of this study was to present aspects of the current treatment protocol, such as patient evaluation and selection for therapy, multimodality monitoring for optimal auditory brainstem implant (ABI) positioning and radiological evaluation, that might have an impact on the functional results of ABI. Out of a series of 145 patients with bilateral vestibular schwannomas 10 patients received an ABI, eight of which are reported here. Patient selection was based on disease course, clinical and radiological criteria (according to the Hannover evaluation and prognosis scaling of neurofibromatosis type 2 (NF2)), extensive otological test battery and psycho-social factors. ABI placement was controlled by multimodality electrophysiological monitoring in order to activate the auditory pathway and to prevent false stimulation of the cranial nerve nuclei or long sensory or motor tracts. Results of hearing function were correlated with patients' ages, duration of deafness, tumour extension, tumour-induced compression or deformation of the brainstem, and numbers of activated electrodes without any side-effects. Out of 59 patients with pre-operative deafness eight patients received an ABI of the Nucleus 22 type. All these patients became continuous users without any side effects and experienced improved quality of life. Speech reception in combination with lip-reading was markedly improved, with further improvement over a long period. A short duration of deafness may be favourable for achieving good results, while age was not a relevant factor. Lateral recess obstruction may necessitate a more meticulous dissection, but did not prevent good placement of the ABI in the lateral recess. Pre-existing brainstem compression did not prevent good results, but brainstem deformation and ipsi- and contralateral distortion were followed by a less favourable outcome. Among the factors that can be influenced by the therapy management are the selection of patients with a slow progressing NF2 disease, a short duration of deafness, a careful analysis of brainstem deformation and consideration of either side for implantation. Long-standing brainstem deformation might not lead to recovery, but instead lead to a low number of active electrodes and possibly only moderate results. ABI treatment is a safe procedure that can increase a patient's quality of life considerably. ABI placement along with neurophysiological control helps to prevent side effects and to improve acoustic activation. Further studies on structural and functional changes of the brainstem after previous tumour compression and distortion should increase our understanding and facilitate a decision on the best side for ABI implantation.

Adult↗
PubMed2000

Extensive monitoring during auditory brainstem implant surgery.

In patients with reduced auditory nerve function, for example due to tumour removal or an accident, hearing rehabilitation can be elicited by an auditory brainstem implant (ABI). The electrode array of the ABI manufactured by Cochlear Ltd., Sydney, consists of 21 circled contacts in a silicon carrier. This is inserted in the lateral recess of the fourth ventricle. Since 1996, in Hannover eight patients have been implanted with a cochlear ABI Nucleus 21 + 1. All of them were profoundly deaf on both sides due to neurofibromatosis type 2 (NF2). To find the optimal electrode position during surgery, a multimodal monitoring by auditory evoked potentials (AEP), electromyography (EMG) and somatosensory evoked potentials (SEP) was performed. When monitoring AEPs, the function of the implant can be checked first by the stimulus artefact. By analysing the AEPs in more detail, the optimal positioning of the electrode on the cochlear nucleus can be found. If systems other than the auditory system are stimulated this will be revealed in one or more of the AEP, EMG and SEP recordings. According to the literature, AEPs stimulated by an ABI consist of three vertex positive peaks with latencies shorter than 4 ms. Typical AEPs are correlated with good post-operative hearing sensation. Comparing these AEPs with AEPs stimulated acoustically or electrically at different sites of the auditory system, it can be assumed that the first peak corresponds to J3, the second to J4 and the last to J5. From this comparison it can also be concluded that no potentials should occur later than 5 ms. This corresponds to our findings. Post-operatively, side-effects occurred when areas of the electrode array were stimulated that showed potentials with latencies longer than 5 ms intra-operatively. Our results indicate that monitoring is an essential aid for the surgeon in finding the optimal electrode position. Positioning solely with reference to anatomical landmarks may not be enough to find the optimal functional position.

Adult↗
PubMed2000

Auditory brainstem implant in auditory rehabilitation of patients with neurofibromatosis type 2: Hannover programme.

An auditory brainstem implant (ABI) is indicated for patients suffering from bilateral neural deafness. The most affected patients are those with neurofibromatosis type 2 (NF2). An implantation is possible either at the same time as, or after, surgical removal of an acoustic neuroma. This paper demonstrates the results of eight out of 11 patients with NF2, seven of whom received an ABI after tumour removal. Pre-operatively, all of them were deaf. Post-operatively, the first fitting served to determine the individual stimulation parameters for each electrode. The stimulation-dependent side-effects were eliminated by reducing the stimulus intensity without causing negative effects on the hearing with the ABI. Only in one case was an open set understanding achieved within the first year. However, all patients had a better speech understanding when they combined their hearing with the ABI and their lip-reading abilities. There is no correlation between the performance with ABI and the tumour size or the duration of deafness.

Adolescent↗