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Biomedical subjects

R Fahlbusch

Publications and source records attributed to R Fahlbusch.

At least 199 records · Page 11Linked to original sources
PubMed1989

Neurophysiologic monitoring in posterior fossa surgery. I. Technical principles, applicability and limitations.

In 135 cases of posterior fossa surgery almost exclusively in the cerebellopontine angle (CPA) intraoperative monitoring of brain-stem acoustic evoked potentials (BAEP) and partly somatosensory evoked potentials (SEP) was performed. The series consisted of 20 microvascular decompressions, 63 acoustic neurinomas, 7 vascular lesions and 45 other space occupying lesions, mostly in the CPA. BAEP monitoring alone was employed in 76 cases, combined BAEP and SEP monitoring less frequently. The technique of anaesthesia and intraoperative monitoring is presented in detail including an analysis of technical problems (17 in 135 = 13% of cases) and technical failures (11 of 135 = 8%). The results of monitoring brainstem pathways contralateral to the lesion are detailed. It is concluded that the technical principles of evoked potential monitoring in posterior fossa surgery are well established. The applications and limits of this technique including its modifications are described.

Cranial Fossa, Posterior↗
PubMed1989

Neurophysiologic monitoring in posterior fossa surgery. II. BAEP-waves I and V and preservation of hearing.

Of 135 cases operated upon for posterior fossa lesions 103 showed preoperative hearing. In 34 acoustic neurinomas 14 had postoperative initially preserved hearing, in 20 microvascular decompressions 19 had preserved postoperative hearing and in 49 other lesions 5 lost hearing. The relationship between preservation of hearing and the preservation or loss of brainstem auditory evoked potentials (BAEP) waves I and V in the three groups of namely: acoustic neurinomas, microvascular decompressions and other lesions are presented. It is noteworthy that only patients with preserved waves I or V are suitable candidates for intraoperative monitoring. The loss of wave V is usually associated with hearing loss (10 out of 13 cases). But hearing loss is also possible despite preservation of wave I (3 out of 60) or despite preservation of wave V (2 out of 68). The predictive value of the preservation of waves I and V is not an absolute one, but it strongly suggests preserved hearing postoperatively. The dilemma remains that once waves I or V are lost during surgery there is no certainty as to postoperative hearing. If wave V recovers after an initial loss, hearing is usually preserved but not in all cases. In wave I amplitude changes alone were more frequent than in wave V, where latency changes alone were more frequently observed. Particular surgical manoeuvres could be found to be often associated with a wave deterioration. Hearing preservation could never be achieved in patients who already preoperatively had no BAEP. It is concluded that BAEP monitoring is of great value in surgery for microvascular decompression and cerebello-pontine-angle (CPA) tumours with preserved hearing.

Audiometry, Evoked Response↗
PubMed1989

[Acute hemorrhage and ischemic necroses in hypophyseal tumors: hypophyseal apoplexy].

Acute enlargement of pituitary adenomas due to haemorrhage or ischaemic necrosis in the tumour was described as "pituitary apoplexy" by Brougham et al. in 1950. Since then, more than 200 cases have been reported, but--especially in the German literature--the syndrome has caught only little attention. Therefore, in a series of 12 own patients, typical findings and clinical characteristics are demonstrated and the literature is discussed. 9 patients had a haemorrhage into the tumour, 3 an acute ischaemic necrosis. The guiding symptom was the acute onset with ophthalmoplegia (11 of 12 patients). Only in one case the adenoma was known before the apoplexy. Other symptoms were headache, blurred vision, drowsiness and, in severe cases, hemiparesis, coma, and hypothalamic disorder. Most important is the acute endocrinological substitution with hydrocortisone; this may be life-saving. Neuroophthalmological recovery depends on early operation: cases of oculomotor palsy require an operation within the first 2 weeks after the acute event. An emergency operation is required only by an acute amaurosis. In general there will be enough time for careful clinical endocrinological and radiological investigations.

Adenoma↗
PubMed1989

Results of dynamic endocrine testing of hypothalamic pituitary function in patients with a primary "empty" sella syndrome.

A total of 52 patients (38 women, 14 men) with a primary "empty" sella syndrome underwent dynamic endocrine testing consisting of insulin-induced hypoglycaemia and a combined anterior pituitary stimulation test utilizing GnRH and TRH. The diagnosis of an "empty" sella turcica was made on the basis of thin collimation CT reconstructions and in addition either metrizamide cisternography or magnetic resonance (MR) imaging. Only 16 of the patients presented with endocrine problems. Hyperprolactinaemia was the most common endocrine disturbance detected, and was found in 17 individuals. Panhypopituitarism was found in 3 patients. Nine other patients had some degree of partial pituitary insufficiency, but only two of them required replacement therapy. However, 31 patients had no evidence of endocrine dysfunction.

Adult↗
PubMed1989

Evaluation of prognostic factors in cerebral arteriovenous malformations.

In a retrospective study of 48 patients who underwent elective surgery for cerebral arteriovenous malformations, a statistical analysis of demographic, clinical, and neuroradiological data was undertaken in order to discover the best predictors of operative morbidity. In addition, the predictive value of different clinical grading systems as applied to this series was compared. All patients had a computed tomographic scan and a positive angiogram before surgery. Complete resection was proven angiographically. The univariate Mann-Whitney-Wilcoxon rank sum test, the Fisher exact test, Spearman's rank correlation coefficient analysis, and multivariate logistic regression were used as statistical methods. Duration of surgery, the development, of either new deficits or an increase in the preoperative neurological signs immediately after surgery, and rehabilitation (as measured by the Karnofsky index) were taken as target variables for the difficulty of operation and for postoperative morbidity, respectively. The largest diameter of the nidus of the arteriovenous malformation, eloquence of the adjacent brain, and deep venous drainage showed the most consistent correlation with these target variables. Intracerebral hematoma and other single factors, such as the age of the patient or localization of the arteriovenous malformation did not affect the outcome. The clinical grading scale of Spetzler and Martin provided better prediction of surgical risks than other proposed systems.

Adult↗
PubMed1989

Endocrine disturbances in suprasellar germinomas.

The authors have investigated hypothalamic-pituitary function in 8 patients (aged 9-27 years) with surgically and histologically proven suprasellar germinomas. Diabetes insipidus was found in 7 patients. All the patients had hypogonadism and hypocortisolism as judged by dynamic endocrine testing. Hypothyroidism was found in 6. Moreover, growth hormone secretion, as assessed by insulin-induced hypoglycemia, was defective in all patients. Comparison of results of insulin-induced hypoglycemia testing and stimulation tests by CRH and GHRH suggested that all patients had a primary suprahypophyseal lesion rather than a primary pituitary defect. The authors conclude that suprasellar germinomas, although uncommon, should be included in the differential diagnosis of juvenile suprasellar tumours and in cases suggestive of idiopathic diabetes insipidus, even if neuroradiological investigation fails to demonstrate a discrete tumour.

Adolescent↗
PubMed1989

The coexistence of pituitary adenomas and meningiomas: three case reports and a review of the literature.

A coexistence of pituitary adenomas and meningiomas is very rare. We have reported on three of our own cases and reviewed the 17 cases reported in the literature. One has to differenciate between the coexistence of a pituitary adenoma and a meningioma without previous irradiation, and the occurrence of a meningioma following the irradiation of a pituitary adenoma. In the cases without irradiation, the adenoma and the meningioma are diagnosed simultaneously. On the other hand meningiomas arising after irradiation of a pituitary tumour are usually diagnosed only after a long latent period. The coexistence of pituitary tumours and meningiomas resulting from hormone dependent growth as well as the induction of growth of meningiomas by irradiation are discussed.

Adenoma↗
PubMed1989

[Function-saving microsurgery in suboccipital removal of large acoustic neuromas].

Various successful approaches are available for acoustic neurinoma surgery, permitting total tumor removal and preservation of cranial nerve function. In smaller and medium sized tumors excellent results can be achieved with respect to facial and cochlear nerve function using the transtemporal approach. For larger tumors similar results can be achieved by the suboccipital approach. The results of 45 completely removed large acoustic neurinomas all operated upon via the suboccipito-lateral approach with microsurgical techniques and neurophysiological monitoring are presented. The average tumor size, excluding the portion within the internal auditory canal was 3 cm. Anatomical preservation of the VIIth cranial nerve was achieved in nearly all cases. Satisfactory to excellent facial nerve function was preserved in 70% of all cases. Initial hearing was preserved in 29%. However delayed postoperative hearing loss was encountered in 13%. Therefore definite hearing preservation was achieved in 16% of the cases. Intraoperative monitoring, especially of auditory evoked potentials, was very helpful in achieving these functional results.

Adult↗
PubMed1988

[Suprascapular nerve entrapment syndrome].

Nineteen patients with isolated suprascapular entrapment neuropathy were seen between 1980 and 1986. A neurogenic cause and absence of other deficits were confirmed by electromyography. Electroneurographic tests were performed in 13 and demonstrated delayed conduction time and (or) reduction in stimulus response amplitude. In 16 patients there was an acute or chronic mechanical cause (direct pressure on the suprascapular nerve, forced dislocation of the shoulder blade). Two types of paralysis could be distinguished, an upper one affecting both the infra- and the supraspinatus muscles (12 patients), and a lower one involving only the infraspinatus muscle (4 patients). In two patients an inflammatory cause was considered likely, while in one the cause remained unclear. Restricting movement brought about an improvement in most patients, while in one the neurophysiological parameters improved after neurosurgical intervention, without complete clinical restoration.

Accidental Falls↗
PubMed1988

Transsphenoidal surgery of parasellar pituitary adenomas.

A series of 147 transsphenoidal operations for parasellar pituitary adenomas performed in a 4.5 year period is presented. The clinical and radiological features of the tumours are described and a new practical classification for the neurosurgeon is introduced. The results of surgery are analyzed with special attention to normalization rates in endocrinologically active adenomas and to the recovery rate of optomotoric nerve lesions in 10 of these cases. While in intra- and parasellar microadenomas the surgical normalization rates are comparable to those not extending beyond the confines of the sella, correction of hormonal oversecretion is only exceptionally observed in invasive parasellar macroadenomas. The prognosis for extraocular nerve palsies was found to be favourable, irrespective of the duration of the palsies before surgical intervention. It is to be stressed that even adenomas invading the cavernous sinus can be totally removed via the transsphenoidal approach.

Acromegaly↗
PubMed1988

Detailed analysis of intraoperative changes monitoring brain stem acoustic evoked potentials.

A series of 31 neurosurgical procedures in the posterior fossa monitored intraoperatively with ipsilateral brain stem acoustic evoked potentials (BAEPs) is analyzed for intraoperative potential changes. The evaluation of patients included pre- and postoperative BAEP recordings and pure tone audiometry. The series included 25 tumors, 4 neurovascular decompressions, 1 basilar artery aneurysm, and 1 arteriovenous malformation. Two intraoperative findings correlated significantly with a postoperative decrease in hearing: an amplitude reduction of more than 50% for Waves I to V and the loss of one of the waves, even if it was a wave that first appeared intraoperatively. We could attribute no significance to reversible or irreversible latency increases for all waves. The transient loss of one of the peaks followed by its reappearance was also insignificant with regard to postoperative hearing. A good prognostic sign was the intraoperative appearance of a peak undetectable on the preoperative recordings. These findings suggest that in intraoperative BAEP monitoring the observation of amplitude reduction is more important than that of latency increases. The surgeon should be informed when an amplitude reduction of more than 50% occurs before the peak is lost totally, as it is impossible to predict whether this peak will reappear intraoperatively.

Adult↗
PubMed1988

[Tumors and space-occupying abnormalities of the skull calotte].

Clinical and demographic data as well as the course of illness were analyzed in a retrospective study of 50 patients with a primary tumor or a malformation of the calvarial bones. The most frequent histological diagnosis was "eosinophilic granuloma of bone" (found in 42% of cases), followed by hemangioma, osteoma, dermoid, epidermoid and malignant tumors, and fibrous dysplasia. Local recurrence was observed in 1 patient with ossifying fibroma and 1 with a dermoid tumor, while further dissemination of illness was observed in 3 patients with "eosinophilic granuloma". In these cases, systemic drug therapy is needed. The necessity of an intensive search for further signs of illness and long follow-up periods in patients with primary localized histiocytosis X is stressed.

Adult↗
PubMed1987

Autoantibodies to pituitary corticotropin-producing cells: possible marker for unfavourable outcome after pituitary microsurgery for Cushing's disease.

Circulating autoantibodies to human fetal pituitary cells were detected in 13 out of 51 patients who underwent transsphenoidal microsurgery for Cushing's disease. The absence of Fc receptors on human fetal pituitary corticotropin-producing cells allowed the detection of antibodies to these cells. In all the 13 patients, the antibodies were present before surgery, and 10 of them showed clinical and/or biochemical signs of incomplete cure of Cushing's disease after surgery. Only 3 out of 27 patients with a favourable outcome were antibody-positive. In all the antibody-positive patients, the antibodies were directed to corticotropin-producing cells and in 8 patients also to luteinising hormone or human growth hormone producing cells. A non-antigen-specific adherence of antibodies to Fc-receptors on corticotropin-cells was excluded by unchanged binding after preincubation of sections with purified rabbit Fc or Fc aggregates. The presence of pituitary corticotropin-cell antibodies in patients with Cushing's disease is associated with an unsuccessful outcome after transsphenoidal selective adenectomy.

Adenoma↗