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Biomedical subjects

R Fahlbusch

Publications and source records attributed to R Fahlbusch.

At least 73 records · Page 4Linked to original sources
PubMed2000

[Clinical applications of single photon emission tomography in neurology. 2. Dementia, psychoses, inflammation, skull and brain injuries].

This article gives in his second part a critical review of the clinical applications of SPECT with perfusion markers and receptor ligands in dementing disorders and psychosis. In addition this review discusses clinical applications of SPECT investigations with perfusion markers in inflammatory diseases of the central nervous system and in brain trauma.

Brain↗
PubMed1999

Functional neuronavigation with magnetoencephalography: outcome in 50 patients with lesions around the motor cortex.

The authors conducted a study to evaluate the clinical outcome in 50 patients with lesions around the motor cortex who underwent surgery in which functional neuronavigation was performed. The sensorimotor cortex was identified in all patients with the use of magnetoencephalography (MEG). The MEG-source localizations were superimposed onto a three-dimensional magnetic resonance image, and the image data set was then implemented into a neuronavigation system. Based on this setup, the surgeon chose the best surgical strategy. During surgery, the pre- and postcentral gyrus were identified by neuronavigation, and in addition, the central sulcus was localized using intraoperative recording of somatosensory evoked potentials. In all cases MEG localizations of the sensory or motor cortex were correct. In 30% of the patients preoperative paresis improved, in 66% no additional deficits occurred, and in only 4% (two patients) deterioration of neurological function occurred. In one of these patients the deterioration was not related to the method. The method of incorporating functional data into neuronavigation systems is a promising tool that can be used in more radical surgery to cause less morbidity around eloquent brain areas.

Journal Article↗
PubMed1999

Xanthogranuloma of the sellar region: a clinicopathological entity different from adamantinomatous craniopharyngioma.

Xanthogranulomatous change of craniopharyngioma, consisting of cholesterol clefts, macrophages, chronic inflammatory infiltrates, necrotic debris and hemosiderin deposits, has been traditionally considered a hallmark of the adamantinomatous variant, even in the absence of epithelium. Based on a series of 110 craniopharyngioma patients undergoing primary surgery, we found 37 specimens with a predominating xanthogranulomatous component. Only 3 of these cases (8%) exhibited additional histological features of adamantinomatous craniopharyngioma, while 13 cases (35%) contained non-adamantinomatous epithelium composed of squamous or ciliated cuboidal cells. Subsequent clinical analysis revealed that these 37 xanthogranulomatous lesions differed from 59 classical adamantinomatous craniopharyngiomas with respect to preferential occurrence in adolescents and young adults (mean age 27 years), predominant intrasellar location, smaller tumor size, more severe endocrinological deficits, longer preoperative history, lower frequency of calcification and visual disturbances, better resectability, and a more favorable outcome. On the other hand, xanthogranulomatous and adamantinomatous lesions did not differ with respect to sex, amount of cystic components, or the intraoperative aspect, considered by the neurosurgeon as being typical for craniopharyngioma in all cases. We suggest that xanthogranuloma (cholesterol granuloma) of the sellar region is clinically and pathologically distinct from the classical adamantinomatous craniopharyngioma.

Adolescent↗
PubMed1999

The prognostic value of intraoperative BAEP patterns in acoustic neurinoma surgery.

Based on a consecutive series of 70 hearing patients with unilateral acoustic neurinomas and intraoperative monitoring of brain-stem auditory evoked potentials (BAEP), 4 dynamic BAEP patterns could be characterized. These patterns correspond with early and late postoperative hearing outcome. All patients with stable wave V (pattern 1) showed definite hearing preservation, all patients with irreversible abrupt loss of BAEP (pattern 2) lost their hearing, despite early hearing preservation in two cases. All patients with irreversible progressive loss of either wave I or wave V (pattern 3) eventually suffered from definite postoperative hearing loss, despite early hearing preservation in two cases. Those cases with intraoperative reversible loss of BAEP (pattern 4) showed variable short and long term hearing outcome. In 34% hearing was preserved, 44% suffered from postoperative hearing loss, the remaining 22% showed postoperative hearing fluctuation, either as a delayed hearing loss or as reversible hearing loss. Postoperative hearing fluctuation indicates anatomical and functional preservation of the cochlear nerve during surgery and is suggestive of a pathophysiological mechanism initiated during the surgical procedure and continuing thereafter. Patients at risk for delayed hearing loss can be identified during surgery by a characteristic BAEP pattern and may benefit from vasoactive treatment.

Audiometry, Pure-Tone↗
PubMed1999

Regression of a large solid papillary craniopharyngioma following fractionated external radiotherapy.

We present a patient harboring a large squamous papillary craniopharyngioma. The diagnosis was confirmed by a stereotactic biopsy. Because of vegetative symptoms indicating hypothalamic derangement, we were reluctant to perform surgical resection. Following fractionated megavoltage radiotherapy, MR imaging and CT demonstrated complete regression of the craniopharyngioma and the patient recovered from endocrine deficiency, chiasmal syndrome and vegetative hypothalamic symptoms.

Brain Neoplasms↗
PubMed1999

Clinical correlates in acromegalic patients with pituitary tumors expressing GSP oncogenes.

We herein review published findings on the clinical characteristics of acromegalic patients harboring pituitary somatotrophinomas expressing adenylyl cyclase activating gsp mutations and present an update of our own data on a large series of 176 patients with and without these oncogenes. Gsp oncogenes are the result of point mutations in either codon 201 or 227 of the Gs-alpha subunit of the Gs-protein which controls adenylyl cyclase. They result ultimately in increased intracellular cAMP levels and thus in excessive growth hormone (GH) secretion. Our large series has allowed us to characterise patients with mutations in codon 201 and the far rarer group possessing codon 227 defects. Both groups were compared with patients without gsp oncogenes. In accordance with previous findings, there was no statistically significant difference in age of the patients belonging to each group, the overall average tumor diameter nor in pre-operative serum GH levels, although the latter showed a tendency to be lower in patients with gsp oncogenes. The distribution of different types of response during an oral glucose tolerance test (no change, paradoxical rise or greater than 50% decrease in serum GH levels) did not differ between the 3 groups. However, the incidence of microadenomas was higher in acromegalics expressing gsp oncogenes in patients possessing mutations in codon 227. Additionally, the incidence of invasiveness was much lower (10% v. 33%) in those tumors with mutations in codon 227. Finally, previous in-vitro data indicating that gsp oncogene-expressing tumors may respond more efficiently to the somatostatin analogue, octreotide, have been confirmed by subsequent in-vivo studies showing a better reduction in serum GH levels in patients with gsp oncogenes. These latter findings suggest that presence of gsp oncogenes may be a marker for good reponsiveness to octreotide. Assessment of gsp oncogene status of surgically removed pituitary somatotrophinomas may thus be helpful in designing optimal medical therapies in those acromegalics requiring further post-operative management of the disease.

Acromegaly↗
PubMed1999

Prolactin-producing pituitary adenoma and carcinoma with neuronal components--a metaplastic lesion.

Recent studies indicate that cells of various epithelial tumors are capable of transformation to neurons. Observing both neurons and neuropil in two prolactin-producing adenohypophyseal tumors, one benign and one malignant, we sought to assess their cellular differentiation, the presence of nerve growth factor receptor, and expression of the dopamine receptor gene using immunocytochemistry, electron microscopy, and in situ hybridization. Light and electron microscopy clearly revealed cells morphologically transitional between adenoma/carcinoma cells and neurons. Large neurons lacked proliferative activity. Neurons in varying number showed immunoreactivity for pituitary hormones including prolactin, growth hormone and alpha subunit in the adenoma and prolactin alone in the carcinoma. The distribution of nerve growth factor receptor staining was similar. In both tumors, in situ hybridization showed mRNAs for prolactin and dopamine receptor within adenohypophyseal cells and neurons. Our results indicate that the occurrence of neurons and neuropil in growth hormone and prolactin-producing pituitary tumors appears to be the result of metaplasia. The process is not limited to benign tumors and may be due to the production of tropic substances by the adenohypophysial cells, which by paracrine/autocrine mechanisms result in transformation of adenoma cells to nerve cells.

Adenoma↗
PubMed1999

Intra- and suprasellar colloid cysts.

During the past 11 years 69 patients underwent transsphenoidal surgery for symptomatic intra- and suprasellar non-neoplastic cysts in our department. Eighteen of them harbored intra- and suprasellar colloid cysts. The most frequent presenting symptoms were oligomenorrhea, galactorrhea, and headaches. One patient presented with polydipsia. One male patient complained about mild hypogonadism and oligospermia. Two male patients presented with symptoms of panhypopituitarism. Endocrine assessment revealed hyperprolactinaemia in 72% of the female patients. Hypogonadism was found in 72%. Panhypopituitarism was found in two cases. During transsphenoidal surgery, a circumscribed collection of colloid material was removed in each case. Additional tumorous tissue was encountered in three cases that harbored a concomitant pituitary adenoma. Biopsies confirmed the surrounding tissue to be normal pituitary tissue. Postoperatively, regular menstrual cycles were found in 82% of the female patients with oligomenorrhea and headaches improved in 80%. Serum prolactin levels were restored in 92%, galactorrhea ceased in 89%. Only in one case deterioration of pituitary function occurred (diabetes insipidus). Symptomatic SIADH occurred in another one. There were no other post-operative complications. We conclude, that transsphenoidal surgery is a safe therapy for treating symptomatic intra- and suprasellar colloid cysts. Surgery is mainly indicated for female patients in childbearing age to restore fertility and to prevent further deterioration of pituitary function. The differential diagnosis is often unclear preoperatively, but a non-enhancing mass on MRI between anterior and posterior lobe may suggest the presence of an intra- and suprasellar colloid cyst.

Adult↗
PubMed1999

Prevalence, predictors and patterns of postoperative polyuria and hyponatraemia in the immediate course after transsphenoidal surgery for pituitary adenomas.

OBJECTIVE: Disturbances of osmoregulation, leading to diabetes insipidus and hyponatraemia are well known complications after surgery in the sella region. This study was performed to examine the prevalence and predictors of polyuria and hyponatraemia after a complete and selective removal of pituitary adenomas was attempted via the transnasal-transsphenoidal approach. DESIGN: 1571 patients with pituitary adenomas (238 Cushing's disease, 405 acromegaly, 534 hormonally inactive adenomas, 358 prolactinoma, 23 Nelson's syndrome, and 13 thyrotropinoma) were daily examined within a 10-day postoperative inpatient observation period. Prevalence of patterns of polyuria (> 2500 ml) and oliguria/hyponatraemia (< 132 mmol/l) were surveyed as well as predictors of postoperative morbidity. RESULTS: 487 patients (31%) developed immediate postoperative hypotonic polyuria, 161 patients (10%) showed prolonged polyuria and 37 patients (2.4%) delayed hyponatraemia. A biphasic (polyuria-hyponatraemia) and triphasic (polyuria-hyponatraemia-polyuria) pattern was seen in 53 (3.4%) and 18 (1.1%) patients, respectively. Forty-one patients (2.6%) displayed immediate postoperative (day 1) hyponatraemia. Altogether, 8.4% of patients developed hyponatraemia at some time up to the 10th day postoperative, with symptomatic hyponatraemia in 32 patients (2.1%). Risk analysis showed that patients with Cushing's disease had a fourfold higher risk of polyuria than patients with acromegaly and a 2.8-fold higher risk for postoperative hyponatraemia. Younger age, male sex, and intrasellar expansion were associated with a higher risk of hypotonic polyuria, but this was not considered clinically relevant. CONCLUSIONS: The analysis illustrates that disturbances in osmoregulation resulting in polyuria and pertubations of serum sodium concentration are of very high prevalence and need observation even after selective transsphenoidal surgery for pituitary adenomas, especially in patients with Cushing's disease.

Acromegaly↗
PubMed1999

New developments in pituitary surgical techniques.

Despite ongoing advances in the pharmacological, radiotherapeutic and endocrine management of pituitary tumours, surgery remains the therapy of choice for the large majority of these lesions. As surgical efficacy is now being judged by more rigorous technical standards and by more stringent endocrine criteria than ever before, such scrutiny has only served to reinforce the fundamental role of surgery in pituitary tumour management. With the revival of the trans-sphenoidal approach, together with its ongoing technical evolution during the past three decades, pituitary tumours have emerged as eminently treatable lesions, with trans-sphenoidal microsurgery affording long-term, high-quality survival in many patients. Pituitary surgery is, however, not without limitation or liability. Even in experienced hands, endocrine and/or oncological remission is not uniformly achieved. Moreover, of those patients in whom such 'cures' can be induced, the durability of the response is not absolute, as tumour recurrence will continue to threaten a small but significant proportion of patients over time. Finally, and notwithstanding the fact that trans-sphenoidal surgery remains one of the safest procedures in contemporary, neurosurgical practice, complications can occur, some of which can be associated with significant morbidity and, on rare occasions, mortality. Clearly, there continue to be areas in need of improvement, and it has been in response to these limitations of contemporary pituitary surgery that neurosurgeons have sought to develop alternative strategies to improve surgical outcome. As a result, a variety of important innovations have been introduced during recent years. Among others, the most important and effective of these have been the application of neuronavigational techniques, trans-sphenoidal endoscopy and intraoperative MR resection control to the standard trans-sphenoidal approach to pituitary tumours. Whereas some advances are conceptual and others are technical, all are helping to push the limits of pituitary surgery to new frontiers of efficacy and safety. In this chapter, the current state of the art of pituitary surgery is reviewed along with those important new developments that, in the foreseeable future, hope to improve the quality of surgical care available to the pituitary tumour patient.

Adenoma↗
PubMed1999

Acromegaly in a family without a mutation in the menin gene.

Familial pituitary tumors are rare. Only 45 cases in 20 families with acromegaly have been reported. A third of the cases (30%) is related to multiple endocrine neoplasia type 1 (MEN 1). We report two cases of acromegaly in one family with pituitary macroadenomas. A 46-year-old woman with elevated serum growth hormone (GH) and insulin-like growth factor (IGF-1) and a failure to supress GH in the glucose tolerance test underwent transsphenoidal surgery 4 years ago. Three years later her 24-year-old son also presented with typical signs of acromegaly. A pituitary macroadenoma was identified by MRT and he also underwent transsphenoidal surgery. There were no symptoms of McCune-Albright syndrome or other forms of endocrine hyperfunction in the two patients. In an attempt to identify the molecular etiology of the tumours DNA was extracted from paraffin fixed tissue from both patients. Exon 7 to 13 of the Gsp-protein and exons 1 to 10 of the menin gene were amplified by PCR. Although Gsp mutations have been identified in 40% of somatotroph tumors, direct sequencing of the PCR products showed no mutations in exons 7 to 13 of Gs alpha. Moreover no mutations were found in exons 1 to 10 of the menin gene. Therefore, molecular causes other than Gsp or menin gene mutations have to be considered as the molecular etiology of acromegaly in this family.

Acromegaly↗
PubMed1999

Integration of functional magnetic resonance imaging supported by magnetoencephalography in functional neuronavigation

OBJECTIVE: In this study, the intraoperative visualization of functional data provided by functional magnetic resonance imaging (fMRI) and magnetoencephalography (MEG) leading to functional neuronavigation is demonstrated in surgery around the motor strip. METHODS: In seven patients with lesions adjacent to the central region, fMRI was performed with a 1.5-Tesla magnetic resonance system, using axial echo-planar imaging with a motor and a sensory task. Somatosensory and motor evoked fields were recorded with a biomagnetometer. fMRI and MEG were matched to an anatomic three-dimensional magnetic resonance image set by a contour fit. Then this three-dimensional image data set was transferred to the navigation microscope and displayed in the eyepieces of the microscope during surgery. Additionally, intraoperative recording of somatosensory evoked potentials was performed for verification of the central sulcus. RESULTS: In all cases, the projection of fMRI and MEG data into the operating viewing field allowed easy identification of the central region, which was confirmed by phase reversal of somatosensory evoked potentials in each case. fMRI and MEG measurements yielded corresponding results in each patient. CONCLUSION: Functional neuronavigation with integration of fMRI and MEG allows the fast identification of eloquent brain areas. The widespread availability of fMRI will result in a broad availability of functional neuronavigation, which will, in turn, contribute to the successful surgery of lesions in eloquent brain areas with lower morbidity.

Journal Article↗
PubMed1999

Panhypopituitarism associated with diabetes insipidus in a girl with a suprasellar arachnoid cyst.

We report on a female patient with a large suprasellar arachnoid cyst (3.5 x 2.5 cm) combined with right optic nerve hypoplasia. She developed growth hormone deficiency and hypothyroidism at the age of 8.5 years, adrenal insufficiency at the age of 11 years, diabetes insipidus and hypogonadotropic hypogonadism at the age of 15 years. When last seen at the age of 19 years she was extremely obese (+5.9 BMI SDS). The endocrine picture suggests that arachnoid cysts might be involved in far more complex hypothalamic-pituitary disturbances than previously thought.

Adolescent↗
PubMed1999

The endocrine spectrum of arachnoid cysts in childhood.

BACKGROUND: On clinical grounds, arachnoid cysts are usually associated with neurological dysfunction. There is little information concerning their involvement in endocrinological disorders. PATIENTS: The experience in 6 children (birth to 12 years) with hypothalamic-pituitary disturbances secondary to the presence of intracranial arachnoid cysts is reported and the literature is reviewed. RESULTS: Three of our children were diagnosed with isolated hormone abnormalities (2 children with precocious puberty and 1 child with growth hormone, GH deficiency). One child presented the unusual combination of GH deficiency and precocious puberty. The remaining 2 children developed panhypopituitarism associated with diabetes insipidus. CONCLUSION: Arachnoid cysts may cause a wide spectrum of endocrinological disorders. Periodical and complete follow-up of every patient is recommended.

Arachnoid Cysts↗