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H J Reulen

Publications and source records attributed to H J Reulen.

At least 55 records · Page 3Linked to original sources
PubMed1998

Resolution of experimental vasogenic brain edema at different intracranial pressures.

Resolution of vasogenic brain edema was examined using the infusion edema model in rabbits. Texas Red-albumin (MW 66,000 D) and sodium fluorescein (MW 376 D) dissolved in artificial cerebrospinal fluid (aCSF) were infused into the white matter of the left frontal lobe of the brain. To quantify the edema fluid cleared by the ventricular system, ventriculo-cisternal perfusion was performed with aCSF. A closed cranial window, implanted above the left parietal brain, served for studying resolution of the artificial edema fluid via the subarachnoid space. CSF-samples were collected in 30 minutes-intervals and analysed with a spectrophotometer. Clearance of edema fluid was examined under low (2-5 mm Hg), medium (9-12 mm Hg), or high (14-17 mm Hg) intracranial pressures (ICP). In the low pressure-group, both edema fluid markers were found in the ventriculo-cisternal and subarachnoid perfusate at 60 and 90 min, in the group with moderately increased ICP at 90 and 120 min, respectively. In the high ICP-group both fluorescence dyes appeared not less than 90 min in the ventricular system, while no increase at all could be found in the subarachnoid space. Our results imply that resolution of edema fluid via both the ventricular system and the subarachnoid space depends on the actual ICP level.

Animals↗
PubMed1998

Monotherapy with dextromethorphan or tirilazad--but not a combination of both--improves outcome after transient focal cerebral ischemia in rats.

Cell death after cerebral ischemia is mediated by a massive release of excitatory amino acids, generation of free radicals, and - a crucial step - calcium influx into cells. We examined the hypothesis that concurrent administration of drugs ameliorating brain damage via different mechanisms would result in a synergistic neuroprotective effect. The neuroprotective efficacy of two clinically available drugs - the N-methyl-D-aspartate and calcium-channel antagonist dextromethorphan (DM) and the antioxidant tirilazad - were studied in monotherapy and in combination in a rat model of transient focal ischemia. Male Sprague-Dawley rats were subjected to 90 min of middle-cerebral-artery occlusion by an intraluminal filament technique. The animals were randomly assigned to one of four treatments (n=10 each): (1) vehicle-treated controls, (2) DM, (3) tirilazad, (4) DM+tirilazad. Drugs or vehicles were administered 15 min before ischemia and at reperfusion. Local cerebral blood flow (LCBF) was bilaterally recorded by continuous laser Doppler flowmetry. Functional deficits were quantified by daily neurological examinations. Infarct volume was assessed planimetrically after 7 days. DM prevented post-ischemic hypoperfusion. Tirilazad did not influence LCBF. Monotherapy with DM or tirilazad improved neurological function and reduced infarct volume by 45% and 48%, respectively. Combination therapy failed to influence neurological recovery and infarct volume. Although, from pharmacological point of view, a synergistic neuroprotective effect is expected, combination of dextromethorphan and tirilazad may lead to mutual inhibition or potentiate adverse effects.

Animals↗
PubMed1998

Technical principles for protoporphyrin-IX-fluorescence guided microsurgical resection of malignant glioma tissue.

Malignant gliomas accumulate fluorescing protoporphyrin IX intracellularly after exposure to 5-aminolevulinic acid, a metabolic precursor of haem. This phenomenon has been exploited for intraoperative identification of residual tumour to enable greater completeness of tumour removal. The present report describes the necessary modifications to the operating microscope to enable microsurgical, fluorescence-guided tumour removal. The system consists of a xenon light source coupled to the microscope, which can be switched from normal white light to violet-blue excitation light (375-440 nm). A longpass filter is introduced into the observer light path to enable observation of tumour fluorescence. Transmission characteristics of excitation and observation filters are chosen to transmit part of the remitted excitation light. Thereby the observer retains an impression of tissue detail, next to tumour porphyrin fluorescence. An integrating three chip CCD camera optimized for red light detection enables documentation of fluorescence findings. The present modifications allow uncomplicated and rapid recognition of red tumour fluorescence and its borders to normal tissue, without interrupting the course of the operation. Tissue detail is great enough to enable tumour resection under violet-blue excitation light during parts of the operation. The system appears to constitute a useful tool for optimizing removal of malignant gliomas on a routine basis.

Aminolevulinic Acid↗
PubMed1998

5 years' experience with a structured operative training programme for neurosurgical residents.

The operative neurosurgical training programme in our clinic was restructured from 1991-93 with the concept of having a frame for the categories and the volume of operations for training year 1 to 6 and to continuously escalate the complexity of the interventions. In the present report the experiences gained so far as well as the deficiencies are described. Between 1991 and 1995 the number of major neurosurgical operations was in the range of 2100 per year, and about 41-48% of these operations were done--under supervision--by residents. By slowly reducing the number of residents from 13 to 9, the trainees started to gain surgical experience earlier, and the average number of operations performed per year increased markedly (from 82 to 122), approximating more to our preplanned figures, also in the various categories. An important aspect is therefore to adapt the number of trainees relative to the available operative case material. According to our preliminary data, about 250-300 operations per year are needed to train adequately one resident. The evaluation also showed deficiencies in some categories, e.g., in pain treatment and peripheral nerve surgery, where care must be taken to better fulfil the official requirements. The object of a 6-year education is to offer a well balanced training programme with systematic escalation of surgical responsibility until full competency is reached. However, this goal needs to be defined more precisely. The plan presented recently by the Committee for Graduate and Postgraduate Education of the German Society of Neurosurgery [1] may serve as a proposal. A personal surgical log-book would allow a much better record and evaluation the progress of the individual trainee as well as the engagement of the teachers.

Clinical Competence↗
PubMed1998

Clinical outcome of supratentorial astrocytoma WHO grade II.

OBJECTIVE: There are divergent opinions about the prognostic value of the extent of surgery and of different histological subtypes in supratentorial astrocytomas WHO grade II. METHODS: We reviewed 75 consecutive patients (36 females, 39 males) with supratentorial astrocytomas WHO grade II (59 primary and 16 recurrent tumours) operated on between 1991 and 1995. RESULTS: Gross total resection could be achieved in 40 astrocytomas, subtotal resection (including biopsy) was performed in 35 cases. Histological assessment confirmed 60 fibrillary, 6 gemistocytic, 9 oligo-astrocytic and no protoplasmic astrocytomas. There were no postoperative deaths. Early outcome 6 to 12 weeks after surgery according to the Glasgow Outcome Scale was good in 46 patients, 24 patients had moderate, and 5 had severe neurological deficits. Survival rates 1, 2, 3, and 4 years following surgery were 100%, 96%, 96%, 96% for patients who underwent gross total tumour resection and 86%, 77%, 77%, 64% for patients with subtotal tumour resection. The cumulative recurrence or progression rates after 4 years were 26% after gross total resection and 80% after subtotal resection, and this result is statistically significant. Recurrences after gross total resection or progressions after subtotal resection occurred more often in gemistocytic astrocytomas (40% and 100%, respectively) than in other subtypes. Dedifferentiation to a more malignant tumour seems to be more prominent in the gemistocytic subtype. CONCLUSION: Gross total resection should be the leading therapeutic option for patients with astrocytomas WHO grade II. For the gemistocytic subtype further studies will have to prove whether additional radiotherapy is of any benefit.

Adult↗
PubMed1998

In vitro and in vivo porphyrin accumulation by C6 glioma cells after exposure to 5-aminolevulinic acid.

Several malignant tissues synthesize endogenous porphyrins after exposure to 5-aminolevulinic acid (5-ALA). The present experiments have been designed to elucidate whether the C6 glioma cell, a model cell for human malignant glioma, similarly synthesizes porphyrins when exposed to 5-ALA, and whether specific synthesis occurs when C6 cells are inoculated into rat brains to form a tumor. In this situation the blood-brain barrier may interfere with 5-ALA availability, and spreading of porphyrins with edema outside the tumor may occur. Flow cytometry is used to determine the course of cell volume and porphyrin fluorescence intensities in cultured C6 cells which are incubated in 1 mM 5-ALA. For the induction of experimental brain tumors, 10(4) untreated C6 cells are inoculated into the brains of rats. After 9 days animals receive 100 mg 5-ALA/kg body weight. Brains are removed after 3, 6, or 9 h and frozen coronal sections obtained for H/E staining or fluorescence spectography. Cultured C6 cells show a linear increase of protoporphyrin IX fluorescence after exposure to 5-ALA, which begins to plateau after 85 min. Marked fluorescence is also observed in solid and infiltrating experimental tumor. However, faint fluorescence also occurs in normal tissue, basal pia, choroid plexus, and, more obviously, in white-matter tracts bordering the tumor (maximal distance: 1.5 +/- 0.7 mm). The observations demonstrate that C6 cells synthesize protoporphyrin IX after exposure to 5-ALA in vitro and in vivo. However, when utilizing 5-ALA for fluorescence detection or photodynamic therapy of brain tumors, attention should be paid to the possibility of protoporphyrin IX occurring outside the tumor.

Aminolevulinic Acid↗
PubMed1998

Intraoperative detection of malignant gliomas by 5-aminolevulinic acid-induced porphyrin fluorescence.

OBJECTIVE: Survival after surgery and radiotherapy for the treatment of malignant gliomas is linked to the completeness of tumor removal. Therefore, methods that permit intraoperative identification of residual tumor tissue may be of benefit. In a preliminary investigation, we have studied the value of fluorescent porphyrins that accumulate in malignant tissue after administration of a precursor (5-aminolevulinic acid) for labeling of malignant gliomas in nine patients. METHODS: Three hours before the induction of anesthesia, 10 mg 5-aminolevulinic acid/kg body weight was administered orally. Intraoperatively, red porphyrin fluorescence was observed with a 455-nm long-pass filter after excitation with violet-blue (375-440 nm) xenon light and was verified by analysis of fluorescence spectra. Fluorescing and nonfluorescing samples taken from the tumor perimeters were examined histologically or used to study the photobleaching of porphyrins by excitation light and white light from the operating microscope. Plasma and erythrocyte porphyrin levels were determined by fluorescence photometry. RESULTS: Normal brain tissue revealed no porphyrin fluorescence, whereas tumor tissue was distinguished by bright red fluorescence. For a total of 89 tissue biopsies, sensitivity was 85% and specificity was 100% for the detection of malignant tissue. For seven of nine patients, visible porphyrin fluorescence led to further resection of the tumor. Under operating light conditions, fluorescence decayed to 36% in 25 minutes for violet-blue light and in 87 minutes for white light. Plasma and erythrocyte porphyrin contents increased slightly, without exceeding normal levels. CONCLUSION: Our observations suggest that 5-aminolevulinic acid-induced porphyrin fluorescence may label malignant gliomas safely and accurately enough to enhance the completeness of tumor removal.

Aged↗
PubMed1998

A paramedian tangential approach to lumbosacral extraforaminal disc herniations.

OBJECTIVE: Extraforaminal disc herniations today are operated on via the so-called lateral approach. Clinical experience has shown that in contrast to levels L2/3-L4/5, this approach may become extremely difficult at the L5-S1 level. According to new microanatomic studies, the previous lateral approaches at this level often do not allow access to the neuroforamen without partial or total destruction of the L5-S1 facet joint. Postoperatively, this may lead to joint irritation with consecutive low back and pseudoradicular pain. To preserve the facet joint, a new approach was developed based on an anatomic study. METHODS: The approach was first considered with the help of bone specimens including ilium, vertebra 5, and sacrum. Thereafter, lumbar maceration specimens were prepared leaving ligaments, intervertebral discs, and joints intact. From these specimens, bony and ligamentous landmarks were deduced. Finally, the approach was tested on seven cadavers. Subsequently, the approach was performed on 13 patients and the intraoperative findings, the clinical feasibility, and the postoperative results were analyzed. APPROACH: After a transverse skin incision above the dorsal curvature of the ilium, the paravertebral muscles are dissected from the ilium medially toward the spinous process. Lateral from the apophyseal joint, a canal is drilled through the spongiosa of the sacrum. Primarily, a thin layer of inner cortex is spared to protect the content of the neuroforamen. Subsequently, it can easily be removed with the dissector to enter the extraforaminal space. In the depth of the drilled canal, the nerve root is found, because it is fixed at the sacrum near the disc space by the anterior lumbosacral ligaments. Riding on the nerve root, the intertransverse ligament and muscle can be removed with the punch. It is then possible to see the neuroforamen and extraforaminal space in front of the joint. Free fragments and contained discs can then easily be found and removed. CONCLUSION: Using this new approach, the L5-S1 joint remains intact. Space for instrumental manipulations is created in areas not essential for joint function. For this procedure, newly defined anatomic landmarks, such as the ileolumbar ligament, upper edge of the sacrum, lateral rim of the apophyseal joint, and para-articular notch, guide the operative route. In accordance with the preliminary anatomic studies, this approach was successfully used in 13 patients, and we think that it is a promising alternative that helps to preserve joint function and dorsal root ganglion integrity.

Adult↗
PubMed1998

A critical reevaluation of the intraluminal thread model of focal cerebral ischemia: evidence of inadvertent premature reperfusion and subarachnoid hemorrhage in rats by laser-Doppler flowmetry.

BACKGROUND AND PURPOSE: The intraluminal thread model for middle cerebral artery occlusion (MCAO) has gained increasing acceptance. Numerous modifications have been reported in the literature, indicating that the technique has not been standardized. The present study was performed to evaluate and optimize the reliability of this model. METHODS: One hundred Sprague-Dawley rats were subjected to MCAO by 2 different intraluminal filaments. Cortical blood flow was continuously monitored over both hemispheres by laser-Doppler flowmetry (LDF). In part I (3-0 filament), we evaluated the incidence of adequate MCAO, subarachnoid hemorrhage (SAH), intraluminal thrombus formation, and the effects of heparinization. In part II (silicone-coated 4-0 filament), we also determined the influence of insufficient MCAO on morphological and functional outcome and the incidence of postischemic hyperthermia. RESULTS: In part I, SAH occurred in 30% and premature reperfusion in 24%. All animals with a decrease in contralateral flow had suffered SAH. Thrombus formation was not observed in any group. In part II, SAH occurred in 8% and premature reperfusion in 26%. There was no difference in outcome between rats with primary MCAO and rats with filament correction. Animals with uncorrected premature reperfusion had significantly smaller infarct volumes and fewer neurological deficits. CONCLUSIONS: SAH and insufficient MCAO may be more common in the intraluminal thread model than previously reported. Inadvertent premature reperfusion contributes to the interanimal variability associated with this model. The incidence of valid experiments increases with the use of a silicone-coated 4-0 filament. Continuous bilateral LDF is indispensable to monitor adequate MCAO and is highly sensitive to recognize SAH.

Animals↗
PubMed1998

Terson's syndrome in subarachnoid hemorrhage and severe brain injury accompanied by acutely raised intracranial pressure.

OBJECT: The syndrome of retinal or vitreous hemorrhage in association with subarachnoid hemorrhage (SAH) is known as Terson's syndrome. The authors' purpose was to determine whether intraocular hemorrhage occurs with similar incidence when caused by severe brain injury accompanied by acutely raised intracranial pressure (ICP). METHODS: Prospective ophthalmological examination was performed in 22 consecutive patients with SAH or severe brain injury and elevated ICP. Thirteen patients were admitted for SAH (World Federation of Neurological Surgeons Grades II-IV) and nine for severe brain injury (Glasgow Coma Scale scores 3-10). Monitoring of ICP was performed at the time of admission via a ventricular catheter. Initial ICP exceeded 20 mm Hg in all patients. Indirect ophthalmoscopy without induced mydriasis was performed within the 1st week after the acute event. Retinal or vitreous hemorrhage was seen in six (46%) of 13 patients with SAH and in four (44%) of nine patients with severe brain injury. Ocular bleeding was found bilaterally in three patients with SAH and in one patient with severe brain injury (18%). Six of the 10 patients with Terson's syndrome died as a result of their acute event. CONCLUSIONS: The present results indicate that Terson's syndrome may be related to acute elevation of ICP, independent of its causes, and may occur with similar incidence in patients with severe brain injury and those with SAH. Because recognition and treatment of Terson's syndrome may prevent visual impairment and associated secondary damage to the eye, increased awareness of this entity in all patients with acute raised intracranial hypertension is recommended.

Acute Disease↗
PubMed1998

Spinal epidural cavernous hemangiomas. Report of three cases and review of the literature.

Epidural cavernous hemangiomas are increasingly identified as a cause of acute or chronic progressive spinal cord syndrome and local back pain or radiculopathy. The authors present three cases of spinal epidural cavernous hemangiomas manifesting as spinal cord syndrome, thoracic radiculopathy, and lumbar radiculopathy. Based on the imaging characteristics of these three cases and a review of the literature, the clinical signs and symptoms and their implications, the role of preoperative neuroradiological diagnosis, and the need for complete surgical resection are discussed. Epidural cavernous hemangiomas display consistent magnetic resonance imaging properties: T1-weighted images most commonly show a homogeneous signal intensity similar to those of spinal cord and muscle, and contrast enhancement is homogeneous or slightly heterogeneous. On T2-weighted images the signal of the lesion is consistently high and slightly less intense than that of cerebrospinal fluid. Frequently, the lesion is characterized by its extension through the intervertebral foramen. Awareness of these characteristics facilitates diagnosis and treatment of the lesions. Despite the risk of bleeding, in all three cases complete surgical excision was achieved.

Adolescent↗
PubMed1997

Neuroprotective properties of a novel antioxidant (U-101033E) with improved blood-brain barrier permeability in focal cerebral ischemia.

Many efforts have been undertaken to develop antioxidants against free radical induced brain damage, 21-aminosteroids, although accumulating in the cell membrane, thus protecting vascular endothelium from peroxidative damage hardly penetrate the blood-brain barrier. A novel group of antioxidants, the pyrrolopyrimidines, has a markedly improved ability to enter the brain parenchyma. In our current study the neuroprotective potential of the 21-aminosteroid U-74389G was compared with that of the pyrrolopyrimidine U-101033E in a rat model of reversible focal cerebral ischemia. Sprague-Dawley rats were subjected to unilateral occlusion of the middle cerebral artery with assignment to one of three treatment arms (n = 10 each), receiving either vehicle, U-74389G, or U-101033E. Regional CBF was recorded bilaterally by laser Doppler flowmetry. In addition, neurological examination was performed daily, with assessment of infarct volume at day seven. U-101033E reduced the infarct volume significantly by 51%, whereas U-74389G afforded non-significant attenuation only. U-101033E was found to improve neurological recovery promptly; animals with U-74389G began to recover only at the end of the experimental observation period. Differences in the regional CBF were not found in the contralateral hemispheres for either treatment group. We conclude that antioxidative compounds which cross the blood-brain barrier are more effective in focal cerebral ischemia than agents which predominantly act on the endothelium of cerebral microvessels.

Animals↗
PubMed1997

Quantitative analysis of brain edema resolution into the cerebral ventricles and subarachnoid space.

Resolution of vasogenic brain edema was examined using a model of infusion of fluid into the brain of rabbits. For this purpose infusion of Texas Red-albumin (MW 67.000 D) and sodium fluorescein (MW 376 D) dissolved in artificial cerebrospinal fluid (mock CSF) was made into the white matter of the left frontal lobe of the brain. In order to quantify the portion of edema fluid which was cleared by the ventricular system, a ventriculo-cisternal perfusion was performed with mock CSF. A closed cranial window was implanted above the left parietal brain for superfusion of the cerebral cortex with mock CSF, in order to study resolution of the artificial edema fluid via the subarachnoid space. CSF-samples were collected in 30 minutes-intervals and analysed with a spectrophotometer. The clearance of edema fluid was examined under low (2-5 mmHg) and medium (9-12 mmHg) intracranial pressure (ICP). In the low-pressure group both edema fluid markers were found in the ventriculo-cisternal and subarachnoid perfusate at 60 min and 90 min, respectively, after start of infusion. In the group with moderately increased ICP the markers appeared at 90 min and 120 min, respectively. The amount of clearance of fluorescent dye via the subarachnoid space was the same in both groups and independent of the intracranial pressure.

Animals↗
PubMed1997

When should residents be exposed to research?

In this paper the planning of research in a neurosurgical training program is discussed. There are good arguments to organize research rotation after one or two years of clinical exposure rather than at the beginning or the end of the program. Teacher as well as resident can prepare the rotation more carefully selecting the topic according to abilities and interests, selecting a suitable research institution, and prepare funding if necessary. The goals of a research rotation, the various categories of basic and applied research, and the length of the research period are being treated.

Career Choice↗
PubMed1997

Evaluation of hemodynamic responses in head injury patients with transcranial Doppler monitoring.

Transcranial Doppler (TCD) can monitor middle cerebral artery (MCA) velocity which can be recorded simultaneously with other physiologic parameters such as end tidal (Et) CO2, arterial blood pressure and intracranial pressure (ICP), in head injured patients. Relative changes in MCA velocity can be used to reflect relative MCA blood flow changes during ICP waves, and also to evaluate cerebral autoregulation, CO2 reactivity and hemodynamic responses to mannitol and barbiturates. The utility and practicality of short intervals of TCD monitoring to evaluate hemodynamic responses, was evaluated in a group of 22 head injured patients (average Glasgow coma score 6). During ICP A waves, MCA velocity always decreased during the peak of the wave, and during ICP B waves, fluctuated synchronously with the ICP. Dynamic cerebral autoregulation, and reactivity to CO2, were reduced within 48 hours of admission. Impaired cerebral autoregulation within 48 hours of admission did not correlate with outcome at 1 month. Mannitol infusion caused an increase in MCA velocity (15.4 +/- 7.9%) which was significantly correlated to the impairment of dynamic autoregulation (r = 0.54, p < 0.0001). The MCA velocity response to a test dose of barbiturates was significantly correlated to the ICP (r = 0.61, p < 0.01) response as well as to the CO2 reactivity (r = 0.37, p < 0.05). Continuous MCA velocity monitoring using TCD may be useful in evaluating a variety of hemodynamic responses in head injury patients and may replace more cumbersome cerebral blood flow techniques which have been used in the past for these purposes.

Adolescent↗
PubMed1997

Dural arteriovenous fistulas including the transverse and sigmoid sinuses: results of treatment in 30 cases.

We report about the treatment and outcome of 30 patients with dural arteriovenous fistulas including the transverse and sigmoid sinuses treated between 1986 and 1995. All patients underwent panangiography for definitive diagnosis. The dAVF were supplied by the external carotid artery system alone (14 patients), both external and internal carotid systems (10 patients) or both anterior and posterior circulation (6 patients). Depending on the venous drainage the fistulas were classified following a modification of Djindjian's description with 18 patients revealing Type I (main sinus with antegrade flow), 5 Type II a (main sinus with reflux into the contralateral sinus). 5 Type II b (cortical veins), 1 Type II a+b (both) and 1 of Type III (direct cortical drainage). Bruit, pulsatile tinnitus and headaches were the most common symptoms. 6 patients presented with intracranial haemorrhage, 4 with progressive neurological deficit or seizures and 3 with dementia. Arterial embolization was performed in all cases except one, where a transvenous approach for balloon occlusion of the transverse sinus was performed. 21 patients were treated by single or repeated embolization alone. Only in 9/21 cases did arterial embolization result in complete occlusion of the fistula. In 12/21 patients incomplete occlusion was achieved. Following embolization 8 patients underwent additional surgery including coagulation of the feeding arteries and arterialized veins, sinus resection and reconstruction of the sinus. Overall, 18 patients were cured, 11 improved and 1 patient was unchanged. There was a total number of 5 complications including transient stroke, transient facial nerve palsy, and a small necrotic skin area following embolization. Venous infarction of the occipital lobe was induced by transvenous occlusion and surgical resection of the transverse sinus in one patient each, respectively. From our results we conclude that the endovascular therapy alone is the treatment of choice in case of Type I fistulas. In dAVF of Type II and III repeated endovascular treatment seems not to be sufficient and additional surgery is necessary.

Adolescent↗
PubMed1997

[Tumor surgery of the speech cortex in local anesthesia. Neuropsychological and neurophysiological monitoring during operations in the dominant hemisphere].

We report on 30 cases where we have used cortical stimulation mapping to define the areas representing sensorimotor, language and speech functions under local anesthesia to facilitate resection of space-occupying lesions near these areas. Under the simplistic concept that Broca's area lies in the frontal operculum (inferior frontal gyrus) and that Wernicke's area is located in the posterior perisylvian area (superior temporal, angular and supramarginal gyri), we found language and speech function to be represented outside these areas in up to 4 stimulation sites of 15 patients. The results of cortical stimulation mapping were therefore essential to decide on the optimal access route to the lesions that were located subcortically and on the optimal resection plane in gliomas. After the limits of these areas and of the lesions had been established with stimulation mapping and with intrasurgical microscopic smear preparations, respectively, lesions were safely removed under continuous monitoring of sensorimotor, language and speech function. Immediately after surgery we encountered language and speech deficits in 9 patients (30%), which resolved completely in 5 and incompletely in 4 instances. Thus, language functions were normal in 26 patients (87%) at the end of the follow-up period. It is concluded that use of this technique allows safe and extensive resection of lesions that would otherwise have been considered hazardous to remove or inexcisable.

Adolescent↗