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ABSTRACT: In an open, prospective study, we embolised intracranial meningiomas in seven patients, without subsequent surgery. Follow-up over a mean of 20 months included serial neurological examination, MRI and MR spectroscopy. Clinically, embolisation had no adverse effects. Symptomatic patients showed clinical improvement. On MRI marked tumour shrinkage occurred after embolisation in six patients, and was most pronounced during the first 6 months. In a young boy the tumour was unchanged despite complete angiographic devascularisation. Embolisation without subsequent surgery may cause substantial tumour shrinkage and thus be used in selected in patients. However, thorough follow-up is mandatory to ascertain the effects of embolisation.
Neuroradiology 08/2003; 45(7):451-5. · 2.82 Impact Factor
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ABSTRACT: Although being established as a standard procedure in intra-operative monitoring in acoustic neurinoma surgery, auditory brainstem responses (ABR) represent a far-field technique bearing some technical limitations. This prospective study was designed to evaluate electrocochleography (ECochG) as a supplementary tool for hearing preservation.
84 patients with unilateral intra-/extrameatal acoustic neurinomas (extrameatal diameter: 5-55 mm) preserving serviceable hearing, were operated on using a combined (neuro-/otosurgical) suboccipital approach. ECochG was recorded simultaneously to ABR following transtympanic insertion of a steel needle electrode into the promontory under otoscopic view.
Serviceable hearing (Class 1-3 according to Gardner/Robertson) was preserved in 43 out of 84 patients (51.2%), of whom 40 showed both ECochG and ABR being preserved. All 24 patients with loss of both modalities became deaf. Hearing preservation was observed in 4 out of 12 patients with preserved ECochG but loss of ABR (waves III-V). The reverse was observed in 2 cases with postoperative deafness. While both ECochG and ABR amplitudes were significantly correlated with pre- and postoperative hearing, latencies of ECochG summating (SP) and action potential (AP) proved to be more reliable indicators for preserved hearing than ABR (peak I/III/V) latencies. The predictive value of baseline ABR amplitudes for postoperative hearing, however, was superior to ECochG parameters. Only in large neurinomas (extrameatal diameter: >2 cm) tumour size was found to be a significant predictor for the preservation of hearing. Apart from three cases with postoperative otoliquorrhea and one further case presenting with local bleeding within the external acoustic meatus, no side effects were observed.
In combination with ABR monitoring, ECochG proved to be a useful supplementary tool for hearing preservation in acoustic neurinoma surgery. It is particularly helpful during electrocautery and drilling, since no averaging is required. Special applications are: (1) small tumours with good serviceable hearing; (2) and/or a large intrameatal portion; (3) cases with lost or endangered contralateral hearing (e.g. bilateral acoustic neurinomas), when the preservation of poor or even non-functional hearing is desirable.
Acta Neurochirurgica 10/2001; 143(10):985-95; discussion 995-6. · 1.52 Impact Factor
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ABSTRACT: The functional preservation of lower (motor) cranial nerves (LCN) is endangered during skull base surgery. Intra-operative EMG monitoring of the LCN IX-XII was investigated in 78 patients undergoing 80 operations on various skull base tumors with regard to technical feasibility and clinical efficacy. Ongoing 'spontaneous muscle activity' (SMA) and 'compound muscle action potentials' (CMAP) following supramaximal bipolar stimulation were intra-operatively recorded applying needle electrodes into the soft palate (CN IX: n=76), the vocal cord (CN X: n=72), the trapezius muscle (CN XI: n=18), and the tongue (CN XII: n=71). From 24/22/8 cases with LCN IX/X/XII deficits (despite monitoring) only 5/6/4 remained unchanged (3-6 months postoperative). An irreversible plegia of the LCN IX/X/XII occurred in three (1/1/1) patients. In 7/6/1 patients postoperative (3-6 months) LCN IX/X/XII function was better than preoperatively. In all patients accessory nerve function remained unchanged. 'Pathological' SMA of the LCN IX/X/XII occurred in 12/16/8 cases, but in only 6/5/3 cases corresponded to postoperative LCN deficits. Corresponding 'pathological' SMA patterns were found in 18/17/5 out of 24/22/8 cases with postoperative LCN IX/X/XII dysfunction. Reproducible CMAP of LCN IX/X/XI/XII could be recorded in 59/56/11/32 patients. Approximate 'normal' values were calculated and compared to (very few) data so far given in the literature. Electromyographic monitoring proved to be a safe tool for the intra-operative identification and localization of the LCN contributing to their anatomical and functional preservation. The predictive value of standard neurophysiological parameters for functional outcome, however, is limited.
Clinical Neurology and Neurosurgery 08/2001; 103(2):72-82. · 1.58 Impact Factor
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ABSTRACT: Extraocular motor nerves (Nn. III, IV, VI) are at risk of damage during skull base surgery. A new recording technique was employed in 18 patients suffering from various skull base tumours in order to extend intra-operative EMG monitoring to the extra-ocular muscles.
Selective intra-operative EMG recordings were obtained from extra-ocular muscles by placement of single-shafted bipolar needle electrodes under the guidance of B-mode ultrasound to visualise the needle tip within the target muscle in the orbital cavity.
Following bipolar electrical stimulation, the oculomotor nerve (N.III) was intra-operatively identified in 5 out of 7 cases, and the abducens nerve (N.VI) in 12 out of 18 cases. Postoperative (3-6 months) oculomotor nerve function remained unchanged in 5 and improved in 2 patients. No permanent deterioration was observed. Abducens nerve function deteriorated in two patients and improved in one case, but remained unchanged in 15 cases. No side effects occurred. There was neither any distinct relation of ocular motor nerve function to the kind and extent of SMA ("spontaneous muscle activity") patterns, nor could such relationship be detected with concern to neurophysiological parameters (latencies, amplitudes) of electrically evoked CMAP ("compound muscle action potentials").
The EMG technique proposed proved to be mainly effective as a mapping tool for intra-operative localisation and identification of ocular motor nerves in skull base surgery. However, the predictive value of conventional neurophysiological parameters for clinical outcome, seems to be rather poor. Further studies on a larger number of patients are therefore required to develop new quantification techniques which enable an intra-operative prediction of ocular motor nerve deficits. Further efforts are also necessary to extend this technique to the trochlear nerve.
Acta Neurochirurgica 02/2001; 143(3):251-61. · 1.52 Impact Factor
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ABSTRACT: To evaluate an interdisciplinary concept (neurosurgery/ear, nose, and throat (ENT)) of treating acoustic neuromas with extrameatal extension via the retromastoidal approach. To analyse whether monitoring both facial nerve EMG and BAEP improved the functional outcome in acoustic neuroma surgery.
In a series of 508 patients consecutively operated on over a period of 7 years, functional outcome of the facial nerve was evaluated according to the House/Brackmann scale and hearing preservation was classified using the Gardner/Robertson system.
Facial monitoring (396 of 508 operations) and continuous BAEP recording (229 of 399 cases with preserved hearing preoperatively) were performed routinely. With intraoperative monitoring, the rate of excellent/good facial nerve function (House/Brackmann I-II) was 88.7%. Good functional hearing (Gardner/Robertson 1-3) was preserved in 39.8%.
Acoustic neuroma surgery via a retrosigmoidal approach is a safe and effective treatment for tumours with extrameatal extension. Functional results can be substantially improved by intraoperative monitoring. The interdisciplinary concept of surgery performed by ENT and neurosurgeons was particularly convincing as each pathoanatomical phase of the operation is performed by a surgeon best acquainted with the regional specialties.
Journal of Neurology Neurosurgery & Psychiatry 09/2000; 69(2):161-6. · 4.76 Impact Factor
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ABSTRACT: Facial nerve monitoring is an established method that is routinely used during cerebellopontine angle tumor surgery. The aim of this study was to determine quantitative electromyographic (EMG) parameters that were predictive of facial nerve outcomes.
In 137 patients with intra-/extrameatal vestibular schwannomas, the most proximal (the exit from the brainstem) and distal (the fundus of the internal auditory canal) parts of the facial nerve were stimulated after total tumor removal. A quantitative analysis of absolute values and ratios (proximal/distal) of evoked EMG parameters (amplitude, latency, and duration) was performed, and parameters were correlated with postoperative (1 and 6 wk and 6 mo) facial nerve function (FNF).
Absolute values of EMG amplitudes were statistically correlated with FNF (P < 0.05). Amplitude ratios (proximal/distal) demonstrated an even greater predictive power. The risk of exhibiting facial palsy 6 months after surgery increased from 1.6% (amplitude ratio of >0.8) to 75% (ratio of <0.1). For EMG latencies, only the ratios revealed a significant correlation with FNF. The latency ratio-dependent risk of facial palsy after 6 months increased from 2.9% (ratio of <1.05) to 33% (ratio of >1.35). The durations of the muscle responses were not significantly correlated with clinical outcomes.
The predictive power of the amplitudes and latencies of electrically evoked muscle responses could be improved by calculating proximal/distal ratios. The proximal/distal amplitude ratio proved to be the most powerful parameter for intraoperative assessment of postoperative FNF.
Neurosurgery 05/2000; 46(5):1140-6; discussion 1146-8. · 2.79 Impact Factor
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ABSTRACT: Since 1991 transcranial doppler sonography has been accepted in Germany as a technical confirmatory test for the assessment of a cerebral circulatory arrest in patients fulfilling the clinical criteria of brain death. This study correlated transcranial doppler findings to established scintigraphic methods such as planar scintigraphy, 99mTc-HMPAO SPECT and EEG patterns. 21 patients (15 males/6 females, mean age 15-69 yrs.) fulfilled all clinical criteria of brain death. They suffered from head injuries and spontaneous bleedings. All clinical and technical investigations were performed within 60-90 minutes. In 14/21 patients clinical findings and all confirmatory tests were consistent with brain death. Planar scintigraphy and SPECT gave completely corresponding results in all 21 patients. 7 patients showed not corresponding results. In two head-injured patients with skull defects TCD yielded an oscillating flow in the MCA but SPECT/planar scintigraphy gave a residual perfusion in the related brain areas. A corresponding residual EEG pattern was seen in one case. A patient with osteoclastic skull defect showed a collateral flow from the external carotid artery and another case a secondary reperfusion in depth of a regular expected MCA signal 12 hours after definitely verification of systolic spikes in the Circle of Willis. No cerebral perfusion was detectable in the scintigraphique techniques. In the three remainder with rest activity in EEG, TCD and radionuclide methods showed no intracranial perfusion. In the presence of open skull fractures, external liquor drainages and osteoclastic craniotomies oscillating flow in TCD does not constantly represent a cerebral circulatory arrest. Awaiting of systolic spikes is absolutely necessary, if no radionuclide method is available. Determination of brain death by TCD should be carried out by an experienced investigator since unexpected collateral flow signals can be misinterpreted.
Zentralblatt für Neurochirurgie 02/2000; 61(1):7-13. · 0.63 Impact Factor
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ABSTRACT: Although aneurysms are widely considered to be of congenital origin there is still debate as to whether some at least might be formed de novo during life. A review of all 49 reported cases plus one previously unpublished case reveals common clinical features and might aid in the management of this group of patients. Statistical analysis of all 50 cases of de novo aneurysms discloses a more frequent history of smoking (P = 0.0007) and arterial hypertension (P = 0.0026) than in a control cohort. Patients with de novo aneurysms are younger (P < 0.0001); the proportion with multiple aneurysms was 28 %. Of de novo aneurysms 44 % became symptomatic 3-6 years after the first subarachnoid haemorrhage (SAH), and the interval was significantly shorter in hypertensive patients. We suggest that young patients with a history of SAH and arterial hypertension and nicotine abuse should therefore be considered for conventional angiography after a 5-year interval. MRA might not be useful due to clip artefacts from even nonferromagnetic clips. Close control of blood pressure is essential in these patients.
Neuroradiology 10/1999; 41(9):674-9. · 2.82 Impact Factor
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ABSTRACT: Although EMG recordings from mimic muscles have become the standard for intra-operative facial nerve monitoring, few data are available concerning other motor cranial nerves (MCN). Auditory brainstem responses (ABR) are a proven tool for intra-operative hearing preservation, but have their limitations, suggesting the application of supplementary methods. This paper describes new developments of MCN and cochlear nerve monitoring in skull base surgery. Up to 2 x 8 EMG channels were recorded after bipolar stimulation of MCN using concentric coaxial probes. A special software enabled event-dependent registrations of all signals exceeding a definable threshold level. Selective recordings from masticatory muscles (N.V) were obtained using rectangular Teflon-insulated needle electrodes. For oculomotor (Nn.III/ VI) nerve recordings bipolar needle electrodes were precisely placed by orbital ultrasound guidance. Lower cranial nerves were monitored inserting needle electrodes into the soft palate (N.IX), tongue (N.XII) and vocal muscles (N.X) during laryngoscopy using a special applicator. For ABR recordings, click stimuli (95 dB HL) were applied monaurally through insert earphones. Electrocochleography was simultaneously recorded as a near-field potential without averaging after promontory (transtympanic) electrode placement using otomicroscopy. Regarding the ABR biosignal, a characteristic response pattern was detected following bipolar electrical stimulation of the auditory nerve possibly useful for its intra-operative identification.
Neurological Research 02/1999; 21(1):11-24. · 1.52 Impact Factor
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ABSTRACT: A 22-year-old woman is reported who attempted suicide by oral ingestion of approximately 10-15 g ammonium metavanadate (NH4VO3). A few hours later she developed gastrointestinal symptoms followed by a transient right sensomotor hemiparesis and aphasic disturbances. Brain MRI and SPECT with 99mTc-HMPAO revealed a lesion in the left parietal cortex. Plasmapheresis, ascorbic acid and desferoxamine led to a complete clinical recovery within a few days.
Clinical Neurology and Neurosurgery 03/1994; 96(1):92-5. · 1.58 Impact Factor
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ABSTRACT: Acetazolamide, a carbonic anhydrase inhibitor, has proved to be useful in the assessment of "vasodilatory capacity" in cerebrovascular disease. To obtain further information on the nature of interictal low-flow regions in migraine, we reinvestigated 20 asymptomatic patients suffering from migraine with aura (n = 15) or without aura (n = 5) and who had either minor (n = 12) or marked (n = 8) regional hypoperfusion when examined in a previous 99mTc-HMPAO SPECT investigation. These patients received acetazolamide IV prior to tracer application. In 14/20 cases regional hypoperfusion resolved. Three patients with migraine with aura had less pronounced regional hypoperfusion compared to baseline. No change in baseline hypoperfusion was detectable in three older patients. No further decreases in flow were measured. In contrast to patients with cerebrovascular ischemia, in whom acetazolamide usually enhances low-flow regions, vasodilatory capacity appears intact in most migraine patients with interictal regional hypoperfusion. Thus, the "acetazolamide test" might be useful in the differential diagnosis of migraine with aura from transient cerebrovascular ischemia.
Cephalalgia 11/1992; 12(5):284-8; discussion 267. · 3.43 Impact Factor
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ABSTRACT: In a double-blind clinical study, antidepressant plasma levels, parameters of platelet serotonin (5-HT) transport (Km, Vmax and basal platelet 5-HT content) and therapeutic response were measured in depressive patients treated with either paroxetine (30 mg/day) or amitriptyline (150 mg/day) for 6 weeks. No correlation could be found between paroxetine plasma levels and therapeutic outcome after 2, 4 and 6 weeks of treatment. In contrast to the amitriptyline group, a marked increase in Km from baseline to week 2 was determined in paroxetine-treated patients, with Km increase being correlated with paroxetine plasma levels at week 2. However, no significant relationship could be found between 5-HT transport parameters and any of the outcome measures in either treatment group.
Acta Psychiatrica Scandinavica 06/1992; 85(5):364-9. · 4.22 Impact Factor
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ABSTRACT: A total of 24 patients with clinical evidence of brain death (n = 17), severe coma (n = 2; GCS approximately 3) and apallic syndrome (n = 4) underwent a comparative investigation with 99mTc-HMPAO brain scintigraphy, EEG, auditory and somatosensory evoked potentials. Accompanied by EEG and evoked potentials, brain scintigraphy enabled confirmation of cerebral death in 15/17 patients. In one case clinical examination and evoked potentials suggest brain death, but cerebral perfusion and EEG were normal ("brain stem death"). One patient with evidence of cerebral death in clinical examination, brain scintigraphy and evoked potentials, showed questionable focal EEG activity; however, autopsy revealed intravital autolysis of the entire brain. All patients with apallic syndrome and deep coma showed a distinct cerebral perfusion, but gross EEG abnormalities; evoked potentials were delayed or absent. Planar scintigraphy with 99mTc-HMPAO appears to be superior to neurophysiological techniques discriminating patients with agonal cerebral dysfunction from those with brain death.
Intensive Care Medicine 02/1992; 18(2):76-81. · 5.40 Impact Factor
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ABSTRACT: From the medical, the juridical as well as the theological point of view brain death represents the death of an individual. According to the German Chamber of Physicians, acute brain damage with coma, absence of all brainstem reflexes and apnoe allows the diagnosis of cerebral death, if repetition of the physical examination after distinct time intervals documents the irreversibility of this state. Additional investigations such as EEG, evoked potentials (BAEP), transcranial doppler sonography, brain scintigraphy or cerebral angiography allow to shorten this period if electrocortical silence, absence of waves 3-5 of BAEP or the cessation of cerebral perfusion has been proven. Strict observation of these criteria is mandatory for the diagnosis of brain death.
Zentralblatt für Chirurgie 02/1992; 117(12):632-6. · 1.02 Impact Factor
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ABSTRACT: Case reports of three headache patients, two with intracerebral meningioma and one with hydrocephalus are presented, in whom the clinical picture fulfilled the criteria of the International Headache Society (IHS) for the diagnosis of migraine. The symptomatic (ie, lesional) nature of the headaches could be detected by neither clinical neurological examination nor routine investigations such as EEG and skull x-ray. On the other hand, brain imaging techniques (CT, MRI) were found to be of particular in value diagnosing the lesions. Our cases indicate that neuroimaging with CT or MRI in the assessment of headache patients should not be handled too restrictively. Compared to CT, however, the additional diagnostic value of MRI in headache seems to be limited.
Headache The Journal of Head and Face Pain 12/1991; 31(10):661-5. · 2.52 Impact Factor
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ABSTRACT: The result of nerve conduction velocity measuring depends upon all components of the measurement system. Earlier investigations showed that the nerve conduction velocity of the sural nerve depends also on technical attributes of recording electrodes. It was the objective of our study to investigate correlations between different recording electrodes and neurophysiological norm values as nerve conduction velocity and latency prolongation after paired stimulation of the sural nerve. Our investigations were carried out in twenty healthy volunteers aged 39 +/- 14 years. Stimulation of the sural nerve was performed at the lateral malleolus using always surface electrodes of the same type. Recording of nerve action potentials was done in each proband by four different types of electrodes. Surface electrodes consisted of tin, stainless steal and sintered silver/silver chloride, needle electrodes of stainless steel. The nerve conduction velocity using silver/silver chloride was 53.6 +/- 4.3 m/sec, using tin electrodes 53.1 +/- 3.9 m/s, using stainless steel 51.4 +/- 3.0 m/s and using needle electrodes 48,7 +/- 2.7 m/s. The Wilcoxon-test confirmed the differences of nerve conduction velocity between needle and silver/silver chloride and tin electrodes yielding p less than 0.05. Latency prolongation after paired stimulation of the sural nerve was independent from electrodes. In conclusion, our results indicate that electrodes take part in the system of standardization. Changing of recording or stimulation electrodes provoke the necessity of new standardization of norm values in clinical neurophysiology.
EEG-EMG Zeitschrift für Elektroenzephalographie, Elektromyographie und verwandte Gebiete 10/1991; 22(3):152-6.
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ABSTRACT: Event-related potentials (ERP) were determined in 138 human immunodeficiency virus (HIV)-infected outpatients and 92 healthy controls of a corresponding age. Of the HIV-infected patients, 31.8% showed an abnormal latency of the P3-component of ERPs (P3-ERP), exceeding the mean value + 2 SD of P3-ERP latencies from age-matched healthy subjects. From the untreated patients in stage Walter Reed (WR) = 6, 71.4% had abnormal P3-ERP latencies, whereas in WR = 2, only 19.6% of P3-ERPs were abnormal. Fourteen patients were observed over a period of 3-16 months. P3-ERP latencies were shortened in 7 patients under treatment with zidovudine. A marked increase in P3-ERP latencies was observed in 7 untreated HIV-infected patients. It is assumed that ERPs are a useful neurophysiological method to detect early cerebral dysfunction in HIV-infected patients.
AIDS Research and Human Retroviruses 08/1991; 7(7):629-35. · 2.25 Impact Factor
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ABSTRACT: The case of a 69-year-old woman with chronic paroxysmal hemicrania (CPH) is presented in whom cerebral perfusion was investigated using the flow tracer 99mTc-hexamethyl propylenamino oxime (HMPAO) and single photon emission tomography (SPECT). There was a bilateral hypoperfusion in the fronto-parietal region between attacks--without medication as well as under effective treatment with verapamil. During an attack, however, SPECT investigation showed a normal cerebral perfusion. Further investigation is required to find out whether these SPECT findings are due to primary alterations of brain perfusion in CPH or are only of epiphenomenological nature. The observed effectiveness of verapamil in the prophylactic treatment of CPH should be verified in a greater number of patients.
Cephalalgia 01/1991; 10(6):311-5. · 3.43 Impact Factor
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ABSTRACT: In a double blind cross-over study, 28 patients, 5 male and 23 female, aged 31 +/- 14 years, after a run-in period of 8 weeks, were treated for 3 months with acetylsalicylic acid and for another 3 months with metoprolol, both in a prophylactic mode. Attack frequency was reduced significantly with both therapeutic regimens (ASA p less than 0.001, metoprolol p less than 0.00005). Reduction of attacks below 50% was seen with metoprolol in 14 cases, and with ASA in three cases. Even though ASA was of statistically significant efficacy in migraine prophylaxis, it clearly is not the drug of first choice in migraine prophylaxis.
Headache The Journal of Head and Face Pain 11/1990; 30(10):639-41. · 2.52 Impact Factor
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ABSTRACT: Brainstem auditory evoked potentials (BAEPs) were recorded in 38 unselected patients (6 m./32 f.; age 18-54 yrs.) with various forms of migraine, during the pain-free interval. The values were compared to those of 50 control persons (18 m./32 f.; age 17-75 yrs.). Peak latencies (PL I-VI), interpeak latencies (IPL I-III, III-V, I-V) and side differences of all peaks (delta I-VI) were calculated. In contrast to PL's of migraine patients, all PL's of control persons were normally distributed. In 6 migraine patients (2 with basilar migraine) PL's were pathologically delayed. Statistical analysis did not show any significant difference in regard to PL's and IPL's between migraine patients and controls. However, side differences of all peaks (except peak IV,VI) were significantly increased in migraine patients as compared to controls. Our results indicate a slight but permanent impairment of brainstem function in migraine.
Headache The Journal of Head and Face Pain 03/1990; 30(3):129-32. · 2.52 Impact Factor
