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Biomedical subjects

G Pendl

Publications and source records attributed to G Pendl.

At least 37 records · Page 2Linked to original sources
PubMed1999

Gamma knife radiosurgery for glomus jugulare tumours.

The aim of this clinical study was to determine the tumour control rate, clinical outcome and complication rate following gamma knife treatment for glomus jugulare tumours. Between May 1992 and May 1998, 13 patients with glomus tumours underwent stereotactic radiosurgical treatment in our department. The age of these patients ranged from 21 to 80 years. The male:female ratio was 2:11. Six patients had primary open surgery for partial removal or recurrent growth and subsequent radiosurgical therapy. Radiosurgery was performed as primary treatment in 7 cases. The median tumour volume was 6.4 cm3 (range: 4.6-13.7 cm3). The median marginal dose applied to an average isodose volume of 50% (30-50%) was 13.5 Gy (12-20 Gy). In 10 patients, a total of 48 MRI and CT follow-up scans were available. The remaining three patients have been excluded from the postradiosurgical evaluation since the observation time (t < 12 months) was too short or patients were lost to follow up. The median interval from Gamma Knife treatment to the last radiological follow-up was 37.6 months (5-68 months). In 4 patients (40%) decreased tumour volumes were observed and in 6 cases (60%) the tumour size remained unchanged. Neurological follow-up examinations revealed improved clinical status in 5 patients (50%), a stable neurological status in 5 patients (50%) and no complications occurred. According to our preliminary experience Gamma Knife radiosurgery represents an effective treatment option for glomus jugulare tumours.

Adult↗
PubMed1999

Gamma Knife radiosurgery of the glomus jugulare tumour - early multicentre experience.

Leksell Gamma Knife was used to treat 66 patients with glomus jugulare tumour at 6 European sites between 1992-1998. The age of the patients ranged between 18-80 years (median 54 years). Gamma Knife radiosurgery was a primary treatment in 30 patients (45. 5%). Open surgery preceded radiosurgery in 24 patients (36.4%), embolisation in 14 patients (21.2%) and fractionated radiotherapy in 5 patients (7.6%). The volume of the tumour ranged 0.5-27 cm(3) (median 5,7 cm(3)). The minimal dose to the tumour margin ranged between 10-30 Gy (median 16.5 Gy). After radiosurgery 52 patients were followed, the follow up period was 3-70 months (median 24 months). Neurological deficit improved in 15 patients (29%) and deteriorated in 3 patients (5,8%), one transient and two persistant. Neuroradiological follow up using MRI or CT was performed in 47 patients 4-70 months (median 24 months) after radiosurgery. Tumour size decreased in 19 patients (40%) while in the remaining 28 patients (60%) no change in the tumour volume was observed. None of the tumours increased in volume during the observation period. Control angiography was performed in 6 patients. Pathological vascularisation completely disappeared in one patient, reduced in two and there was no change in the remaining three. Radiosurgery proves to be a safe treatment for glomus jugulare tumour with no mortality and no acute morbidity. Because of its naturally slow growth rate, up to 10 years of follow up will be necessary to establish a cure rate after radiosurgery for these lesions.

Adolescent↗
PubMed1999

Radiosurgery of vestibular schwannomas: a minimally invasive alternative to microsurgery.

From April 1992 till December 1998 stereotactic radiosurgery (Gamma Knife) was applied to 192 patients with vestibular schwannomas. 56 of them had radiosurgery as primary treatment modality and were followed-up for at least 4 years (48-80 months, median 62). Without fatal complications, control of tumour growth was achieved in all but three cases, useful hearing being preserved in more than one half of the patients (62%). The neurological state improved in 30 patients (54%). Irradiation-associated adverse effects (18%) comprised neurological signs (incomplete facial palsy, four cases (two recovered completely), and mild trigeminal neuropathy, three cases, respectively) and morphological changes (three patients) marked by an enlargement of pre-existing cystic components calling for additional surgical treatment: Microsurgical decompression was performed in two cases, the third patient underwent a shunting procedure because of hydrocephalus formation. Based on the present data, radiosurgery represents an effective treatment for vestibular schwannomas associated with an exceptionally low mortality rate and a good quality of life. With respect to the preservation of cranial nerve function, results are comparable to microsurgical resection. A short duration of hospitalization and a quick return to normal activities constitute further advantages and contribute to cost effectiveness in public health care.

Adolescent↗
PubMed1999

Corpus callosotomy with radiosurgery.

OBJECTIVE: Corpus callosotomy is a surgical option for medically uncontrolled generalized epilepsy in appropriate patients. Because numerous complications related to open callosotomy are still reported, we performed radiosurgical corpus callosotomy with the gamma knife. METHODS: Between October 1992 and June 1995, three patients underwent stereotactic radiosurgery to ablate the anterior third of the corpus callosum. The patients had intractable epilepsy: two had Lennox-Gastaut syndrome, and one had multifocal epilepsy with atonic, tonicoclonic, and atypical absence seizures. The history of seizures ranged from 20 to 37 years' duration. Stereotactic radiosurgery was performed with a cobalt-60 gamma knife using a 4-mm collimator, targeted to the rostrum, genu, and anterior third of body of the corpus callosum. Two patients were treated once with 150 and 160 Gy at maximum, respectively, and one patient was treated in two stages with 50 Gy and then 170 Gy at maximum. RESULTS: The severity and frequency of seizures were significantly reduced in all three patients. The types of seizures associated with the most improved outcome were atonic and generalized tonicoclonic seizures. The mean follow-up period was 38 months. Hospitalization required for this procedure was 3 days. No complications related to irradiation were recorded except transient headache in one patient. CONCLUSION: The outcomes suggest that radiosurgical corpus callosotomy may be a promising alternative treatment to open callosotomy.

Adult↗
PubMed1999

Gamma Knife radiosurgery for epilepsy associated with cavernous hemangiomas: a retrospective study of 49 cases.

A retrospective multicenter study was performed to evaluate the effectiveness of Gamma Knife radiosurgery (GKRS) in the treatment of drug resistant epilepsy associated with cavernous hemangiomas (CH). The mean duration of epilepsy before GKRS was 7.5 ¿ 9.3 years. The mean frequency of seizures was 6.9 ¿ 14/month. The mean marginal dose was 19.2 ¿ 4.4 Gy (range 11.3 to 36 Gy). The mean follow up was 23.7 ¿ 13 months. At the most recent follow-up examination, 26 (53%) patients were seizure-free (Engel s class I) including 24 in class IA (49%) and two (4%) patients with occasional auras (class IB, 4%). A highly significant decrease in the number of seizures was achieved in 10 (20%) patients, which is class lIB. The remaining 13 (2.6%) patients showed little or no improvement. A medial temporal location was associated with a higher risk of failure. In contrast, all patients with central region CH were seizure free. Two severe but transient complications were observed. There was hemorrhage in one patient and another patient suffered from radio-induced edema with transient aphasia. This series is the first demonstrating that GKRS can be used safely and efficiently to treat epilepsy associated to CH. Seizure control can be reached when a good electro-clinical correlation exists between CH location and epileptogenic zone. Our findings suggest that GKRS can be used to treat epilepsy for CH located in highly functional areas, particularly the central region.

Adult↗
PubMed1999

Radiosurgery of glomus tumors: midterm results.

Glomus tumors (GT) of the skull-base present a complex surgical challenge due to their delicate localization and specific vascular supply. This study is designed to evaluate the role of stereotactic radiosurgery in the treatment of GT. Thirteen patients with GT have been treated with the Gamma Knife. Radiosurgery was performed because of recurrences after surgical removal in six patients. Histology was not available in seven patients, thus, diagnosis was made from neuroradiological features only. Two of them had partial embolization before Gamma Knife treatment. Clinical and morphological data were collected from 11 patients, who had a representative follow-up of at least 12 months. Mean follow-up was 42 months (range 14 to 72 months). Within the follow-up period there was no tumor progression and no clinical deterioration in any of the patients. 64% of the patients had an improvement of their symptoms, and in 36% the volume of the lesion decreased in size. There was no radiation-related morbidity. It is suggested that radiosurgery seems to be safe and effective in the treatment of GT.

Adult↗
PubMed1999

A six year experience with the postoperative radiosurgical management of pituitary adenomas.

Since April 1992, 73 consecutive patients with pituitary adenomas were treated with radiosurgery. There were 31 hormonally inactive adenomas and 42 hormonally active adenomas. All but three patients had been subjected to one or more surgical procedures prior to radiosurgery. Three patients had received fractionated radiotherapy. In the inactive adenoma group, the mean target volume was 4.4 ¿ 3 cm3 and the mean prescription dose was 13.8¿1.5 Gy. In the prolactinoma patients, the mean target volume was 6.7 ¿ 9 cm3 and the mean prescription dose was 14.2 ¿4 Gy. In the acromegalic patients, the mean target volume was 2.9¿2.5 cm3 and the mean prescription dose was 16¿4 Gy. ACTH secreting adenomas had a mean target volume of 3.6 ¿ 5.5 cm3 with a mean prescription dose of 17 ¿4.8 Gy. The mean follow-up time was 28.9 ¿ 21.5 months. Follow-up data was available in 83.6% of the patients. Tumor control was achieved in 98.3% and the endocrinological cure rate was 57%. Pituitary function deteriorated in 19.2%. No patient suffered from radiation induced visual damage. It would seem that postoperative radiosurgery for residual or recurrent pituitary adenomas may be a safe technique that can increase the frequency of therapeutic success.

Adenoma↗
PubMed1998

Boron neutron capture therapy for glioblastoma: improvement of boron biodistribution by hyaluronidase.

Boron neutron capture therapy (BNCT) represents a highly promising therapeutic alternative for the treatment of the most common malignant brain tumor, glioblastoma multiforme. Both the efficacy and safety of BNCT are greatly dependent on the pattern of 10B biodistribution. The present study investigates the influence of systemic hyaluronidase applied in combination with Na2B12H11SH (BSH), a boron carrier used in current clinical trials. The application of hyaluronidase was associated with a statistically significant improvement in the tumor/blood boron concentration ratio which suggests that hyaluronidase is capable of enhancing the therapeutic potential of BSH.

Boron↗
PubMed1998

Outcomes in patients treated with gamma knife radiosurgery for brain metastases from malignant melanoma.

In order to determine the effectiveness of gamma knife (GK) radiosurgery in patients with malignant melanoma metastases, the authors conducted a prospective multicenter study. Forty-five patients with a total of 96 lesions were treated and followed to measure survival time, tumor control rate, and Karnofsky Performance Scale (KPS) score. The mean survival time was 8.7 months (median 4.2 months), and tumor control was achieved in 86% of lesions. When obtained, the median preoperative KPS of 80 was maintained at a median of 80 post-GK treatment. The authors found GK treatment for metastases of malignant melanoma to be highly effective in controlling tumor growth. Survival rates obtained after GK treatment were found to be superior to historically obtained data concerning external beam radiotherapy follow up. Radiosurgery with the GK can therefore be considered a good primary treatment option for metastatic brain disease of malignant melanoma.

Journal Article↗
PubMed1998

Treatment options and time course for intramedullary spinal cord metastasis. Report of three cases and review of the literature.

Surgical treatment of intrameduallary spinal cord metastases (ISCM) has become increasingly effective in recent years. The advent of new imaging techniques combined with an enhanced understanding of the natural history of these tumors has improved the effectiveness of the available treatment options. The authors present three new cases of ISCM successfully treated with surgery. A review of 129 cases found in the literature is also discussed. Characteristic symptomology and presentation are reviewed with an eye toward improving diagnostic methodology. The natural history of ISCM is divided into three phases. Surgical intervention should be used early in phase 2.

Journal Article↗
PubMed1998

The costs of radiosurgical treatment: comparison between gamma knife and linear accelerator.

Radiosurgical treatment can be carried out by means of a Gamma Knife or a Linear Accelerator. The Linear Accelerator may be either a single-purpose appliance, exclusively employed in radiosurgery, or an adapted appliance, which is used primarily for fractioned radiotherapy, and only additionally for radiosurgical purposes. The first alternative will be referred to briefly as a "dedicated Linac", the latter as an "adapted Linac". Cost accounting data for these alternatives will be discussed under three main categories: investment costs, operating costs, and finally staffing costs. Costs are only considered to the extent that this is necessary to facilitate a comprehensive cost comparison. Factors for which the costs remain the same or at least broadly the same will from the outset not be taken into consideration. These include, for instance, the costs of general or special administration, diagnosis, and image processing. The results and conclusions of this study therefore cannot be employed immediately in the evaluation of cost reimbursement schemes of the type carried out by agencies responsible for social insurance. Here, appropriate complete cost analyses especially for this purpose are required. The final comprehensive cost comparison reveals that the adapted Linac is the most favourable alternative with small annual quantities of patients. With larger numbers of patients the Gamma Knife represents the most favourable from a cost accounting angle. The dedicated Linac accordingly does not have a cost advantage for any of the examined numbers of patients. Clearly the lowest treatment costs per patient can be achieved by employing a Gamma Knife and using it to capacity.

Austria↗
PubMed1998

Gamma knife radiosurgery and albendazole for cerebral alveolar hydatid disease.

Standard treatment of cerebral alveolar hydatid disease consists of open brain surgery and systemic albendazole. We describe a patient with inoperable cerebral alveolar hydatid cysts on whom gamma knife radiosurgery was used instead of open brain surgery. Because of the size of the multicystic lesion, the gamma knife procedure was done in two sessions. Repeated courses of albendazole were given concurrently. Magnetic resonance imaging follow-up studies showed marked shrinkage of the irradiated cystic structures and initially increased perifocal edema. At a follow-up visit 3 years after gamma knife radiosurgery, the polycystic lesion, the perifocal edema, and the neurological symptoms had all markedly decreased. The patient is now stable and has minimal neurological symptoms, and the quality of her life has improved. Gamma knife radiosurgery may be an alternative for patients with cerebral alveolar hydatid disease for whom surgery is not possible.

Adult↗
PubMed1998

Echographic findings in uveal melanomas treated with the Leksell gamma knife.

BACKGROUND/AIMS: Between June 1992 and July 1995, 29 uveal melanomas were treated radiosurgically with the Leksell gamma unit at the University of Graz. The aim of this retrospective study was to examine the pattern of regression and the extent and time period of the decrease in tumour size. METHODS: The Leksell gamma knife, model B, was used. Patients were divided into three groups according to marginal dose: group 1: eight patients with a marginal dose > 50 Gy, group 2: 15 patients with a marginal dose = 50 Gy, and group 3: six patients with a marginal dose = 45 Gy. For the retrospective study two groups were examined: group A, tumours < 5 mm and group B, tumours > or = 5 mm. RESULTS: No significant correlation was found between tumour regression and the marginal dose. Tumour shrinkage depends on the pretreatment height. In the group of eight patients with an initial tumour prominence of less than 5 mm, no prominence was found after therapy. In the group of patients with an original tumour prominence of 5 mm and more, only two tumours formed a flat scar while a residual prominence was found in 18 patients. Increase in reflectivity combined with a decrease in size appears to be a good criterion for the effectiveness of the treatment. In five patients with tumours showing low reflectivity, over a longer period of time metastases were found. An enucleation was performed in two patients because of uncertain tumour regression and in one patient as a result of an increase in tumour size. CONCLUSION: The pattern of echographic reflectivity and decrease in size is similar to brachytherapy and is one of the most important diagnostic variables for evaluation of tumour regression. An increase in reflectivity as well as a decrease in tumour size in the first 6-8 months can be considered a therapeutic success.

Adult↗
PubMed1998

Cavernous sinus meningiomas--what is the strategy: upfront or adjuvant gamma knife surgery?

43 patients with meningiomas of the cavernous sinus form the basis of this study. Two patients were treated with microsurgery alone, 17 patients were treated by Gamma Knife radiosurgery (GKRS) as a primary treatment modality, and 24 patients underwent a combined treatment of microsurgery followed by GKRS. Therefore, in 17 patients the diagnosis rested on clinical and radiological criteria alone. Cranial nerve disorders (CND) related to open surgical treatment were infrequent in this material (3 of 13 patients) due to deliberate strategies of partial or subtotal resection aimed at sparing cranial nerves from surgical maneuvers. In contrast, 6 of 11 patients, admitted for GKRS from other institutions suffered from considerable CND after open surgery and showed only partial improvement after GKRS. In all GKRS cases, no radiation-related complications were seen after a follow-up of 18-62 months (mean 39 months). Moreover, in all cases tumor control was obtained with a stable tumor volume in 63%, reduction of volume in 34.5% and a disappearance of tumor in 2.5%. GKRS is not only an additional treatment for meningiomas involving the cavernous sinus, but may be offered to the patient as an alternative primary treatment.

Adolescent↗
PubMed1998

Radiosurgery in lesional epilepsy: brain tumors.

The purpose of this study was to examine the effects of different doses of radiation to the brain tissue immediately adjacent to tumors which were associated with epilepsy. From April 1992 to December 1995, 26 patients with medically intractable tumor epilepsy (mean duration 6.9 years, range: 1-27 years) have been treated with Gamma Knife radiosurgery (GKRS). Clinical and imaging controls were available for 24 patients with a mean follow-up of 2.25 years (range: 1-4.4 years). Tumor control had been achieved in all patients. The patients were divided into two groups according to the volume of tissue outside the tumor which had received 10 Gy or more. This volume was assessed by measuring the ratio of the tumor and the ratio of the volume within the isodose containing 10 Gy (10G/Tum ratio). 54 percent of all the 24 patients achieved an excellent result according to the Engel classification (class I or II). The patients were divided into two groups. In group I were 12 patients, and the 10G/Tum ratio was 3 or less. In group II there were 12 patients and the 10G/Tum ratio was more than 3. In group I the mean value for the 10G/Tum ratio was 2 (range 0.86 to 2.9). In group II the mean value of the ratio was 11.1 (range 3.13 to 63.2). In group I only 42% of patients achieved an excellent result compared with 66% in group II. Moreover, the location of the tumor had an effect on the results, in that temporal tumors were associated with excellent results in 64% of cases as opposed to 40% in extratemporal tumors. Finally, if the epilepsy had lasted for 2.5 years or less there were excellent results in 70% of patients, as opposed to 43% excellent results for patients who had suffered epilepsy for more than 2.5 years.

Adolescent↗
PubMed1998

Treatment of cerebral radionecrosis by hyperbaric oxygen therapy.

Clinically observed adverse radiation effects (ARE) are rather uncommon, but modern imaging reveals that they are more common after radiosurgery than previously believed. Little is known about the pathogenesis, and current treatment is mostly empirical. The benefit of hyperbaric oxygen therapy (HBO) on radiation-induced bone and soft tissue necrosis is known in lesions in the maxillofacial area, the mouth and in the head and neck. HBO raises the tissue pO2 and initiates a cellular and vascular repair mechanism. This forms the basis for the hypothesis that it might also help alleviate the results of cerebral radionecrosis. This study is a preliminary attempt to test this hypothesis. Two patients with arteriovenous malformations (AVMs) were chosen for the study. They had been treated with Gamma Knife radiosurgery (GKRS) and had developed imaging signs consistent with ARE. They were treated by breathing 100% oxygen at 2.5 atmospheres absolute (250 kPa) in sessions of 60 minutes per day. This treatment was repeated 40 times in cycles of ten sessions. Both responded well to HBO, one lesion disappeared and the other was reduced significantly in size. No adjuvant steroids were given. These results give evidence that HBO has a potential value in treating ARE but further experience will be needed to confirm its definite benefit.

Adult↗
PubMed1998

Dose-response tolerance of the visual pathways and cranial nerves of the cavernous sinus to stereotactic radiosurgery.

UNLABELLED: As the number of patients treated with stereotactic radiosurgery increases, it becomes particularly important to define with precision adverse effects on distinct structures of the nervous system. OBJECT: This study was designed to assess the dose-response tolerance of the visual pathways and cranial nerves after exposure of the cavernous sinus to radiation. METHODS: A total of 66 sites in the visual system and 210 cranial nerves of the middle cranial fossa were investigated in 50 patients who had undergone gamma knife treatment for benign skull base tumors. The mean follow-up period was 40 months (range 24-60 months). Follow-up examinations consisted of neurological, neuroradiological, and neuroophthalmological evaluations. The actuarial incidence of optic neuropathy was zero for patients who received a radiation dose of less than 10 Gy, 26.7% for patients receiving a dose in the range of 10 to less than 15 Gy, and 77.8% for those who received doses of 15 Gy or more (p < 0.0001). Previously impaired vision improved in 25.8% and was unchanged in 51.5% of patients. No sign of neuropathy was seen in patients whose cranial nerves of the cavernous sinus received radiation doses of between 5 and 30 Gy. Because tumor control appeared to have been achieved in 98% of the patients, the deterioration in visual function cannot be attributed to tumor progression. CONCLUSIONS: The structures of the visual pathways (the optic nerve, chiasm, and tract) exhibit a much higher sensitivity to single-fraction radiation than other cranial nerves, and their particular dose-response characteristics can be defined. In contrast, the oculomotor and trigeminal nerves have a much higher dose tolerance.

Actuarial Analysis↗