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R Fahlbusch

Publications and source records attributed to R Fahlbusch.

At least 19 recordsLinked to original sources
PubMed2006

[CranioNet -- an interdisciplinary strategy for craniopharyngioma].

In patients with craniopharyngioma, pituitary failure and often lifelong hormone replacement therapy, persisting ophthalmological problems with impaired vision, cranial nerve palsies, and psychoneurological deficits will lead to a persisting impairment in quality of life and social competence. Some patients completely depend on assistance. To prevent this, a major goal is an early diagnosis and limitation of operative radicality to minimize postoperative complications. Surgery in centers with special expertise is mandatory. Radiotherapeutical strategies are relatively safe and improve the outcome and recurrence-free survival after incomplete surgical resection or after local recurrence. Multidisciplinary concepts and prospective data acquisition are desirable with regard to therapy and outcome in patients with craniopharyngioma. Problems in the follow-up period are the development of atherosclerotic complications and metabolic syndrome as a consequence of occasionally excessive obesity, which may impair the long-term survival of the patients. Cause and progression of these complications are not fully understood, therapeutical strategies for the morbid obesity are not available. Only interdisciplinary co-operation will help to develop and evaluate therapeutical concepts for the management of this rare disease.

Combined Modality Therapy↗
PubMed2006

Intraoperative high-field MRI: anatomical and functional imaging.

Intraoperative high-field magnetic resonance (MR) imaging with integrated microscope-based navigation is at present one of the most sophisticated technical methods providing a reliable immediate intraoperative quality control. It enables intraoperative imaging at high quality that is up to the standard of up to date pre- and postoperative neuroradiological routine diagnostics. The major indications are pituitary tumor surgery and glioma surgery. In pituitary tumor surgery intraoperative MRI helps to localize hidden tumor remnants that would be otherwise overlooked. The same is true for glioma surgery, where the optimal extent of resection by simultaneous preservation of functional integrity can be achieved. This is possible since high-field MR imaging offers various modalities beyond standard anatomical imaging, such as MR spectroscopy, diffusion tensor imaging, and functional MR imaging which may also be applied intraoperatively, providing not only data on the extent of resection and localization of tumor remnants but also on metabolic changes, tumor invasion, and localization of functional eloquent cortical and deep-seated brain areas.

Brain Neoplasms↗
PubMed2006

Alveolar rhabdomyosarcoma of the clivus with intrasellar expansion: Case report.

Rhabdomyosarcomas are common tumors of the head and neck region in children. However, a primarily intracranial localization of this tumor entity is rare. We report on a 3-year-old boy presenting with double vision due to left VI (th) nerve palsy. No other neurological deficits were recognized by clinical inspection. MRI scans visualized an enhancing mass lesion in the upper clivus compressing the cavernous sinus and the pituitary gland. Transsphenoidal biopsy was performed and histopathological examination as well as molecular diagnostics confirmed the diagnosis of an alveolar rhabdomyosarcoma (ARMS). Staging identified a metastatic lesion in the fourth thoracic vertebra resulting in the diagnosis of stage IV disease. Treatment modality included stereotactic radio- and chemotherapy.

Abducens Nerve Diseases↗
PubMed2005

DNA-flow cytometry of 207 pituitary adenomas: ploidy, proliferation, and prognosis.

The principal factors involved in pituitary adenoma formation are unknown. DNA-flow cytometry is a useful study providing an estimation of a tumor proliferative rate. In this study, DNA-flow cytometry was performed to evaluate its capability to both assess prognosis and predict recurrence. Two hundred and seven fresh pituitary adenoma specimens were assessed by flow cytometry. Pre-operative endocrine function, previous medical treatment, radiographic appearance, surgical findings and immunohistochemistry were recorded for each patient. Patient outcomes were assessed at a mean follow-up of 5.3 +/- 3.1 yr. Endocrinologically inactive pituitary adenomas were predominantly euploids (50.8%). The highest proliferation rates occurred in Nelson's syndrome and the lowest in Cushing's disease. A significant difference in proliferation was observed with prolactinomas and acromegaly when a medical treatment was performed before primary surgery. Massive histological invasiveness was directly associated with a significant increase in proliferation rate. Radiotherapy did not affect the recurrence rate (4.4%) statistically. In conclusion, DNA-flow cytometry was found to be useful for determining ploidy and obtaining an overview of cell cycle status. It was helpful in identifying patients requiring closer follow-up, such as those with invasive adenomas and Nelson's syndrome. No single parameter revealed by DNA-flow cytometry could predict tumor prognosis or recurrence in the follow-up of 7.5 +/- 1.3 yr.

Adenoma↗
PubMed2005

[Endonasal removal of a large recurrent craniopharyngioma using intraoperative navigation].

In recent years computer-navigation systems have been commonly used in the field of otorhinolaryngology. Taking its limitations and possible failures into account, this technology is considered reasonable and helpful in routine paranasal sinus surgery, particularly in revision cases and complex approaches to the lateral skull base. We report on a patient with a large recurrent craniopharyngioma, and show that the use of intraoperative navigation might even be necessary to accomplish the desired postoperative outcome in certain cases. Future developments will demonstrate whether computer assisted surgery can extend the indications for operative procedures in complex anatomical regions.

Child↗
PubMed2005

Visualization of the pyramidal tract in glioma surgery by integrating diffusion tensor imaging in functional neuronavigation.

OBJECT: The aim of this study was to investigate whether diffusion tensor imaging (DTI) can be integrated into functional navigation for the intraoperative visualization of the pyramidal tract. METHODS: A single-shot spin-echo diffusion-weighted echo planar imaging sequence on a 1.5 T magnetic resonance (MR) scanner was used for DTI. One null image and six diffusion-weighted images (high B value 1 000 mm/s (2)) were obtained. Color-encoded fractional anisotropy maps of the principal eigenvector rendered as a boxoid within each voxel were used for segmentation of the pyramidal tract. The segmented images were rigidly registered with a T(1)-weighted gradient echo 3D dataset for navigation in 16 patients with gliomas. In tumors adjacent to the motor cortex (n = 6) data from functional MR imaging were co-registered. RESULTS: The whole DTI processing lasted about 25-30 minutes in each case. In all cases DTI could be integrated into the navigational dataset resulting in an intraoperative visualization of the pyramidal tract by microscope-based navigation. Navigational accuracy measured as the target registration error was 1.2 +/- 0.46 mm. Registration of fractional anisotropy maps with the 3D navigational dataset was possible with an error of less than 2 mm. Co-registration with fMRI was consistent with DTI data. A neurological deterioration was observed only in one patient. CONCLUSIONS: DTI can be reliably integrated into navigational datasets. Thus, microscope-based neuronavigation can be used for an intraoperative visualization of the course of the pyramidal tract. However, a possible shifting of the pyramidal tract has to be taken into account after major tumor parts are removed.

Adolescent↗
PubMed2005

Analysis of secretory, immunostaining and clinical characteristics of human "functionless" pituitary adenomas: transdifferentiation or gonadotropinomas?

In this study, the central technique of in vitro culture has been used to further investigate whether LH/FSH-expressing, but clinically "functionless" pituitary adenomas are gonadotropinomas or whether their hormone secretion is due to transdifferentiation events. 664 "functionless" pituitary adenomas were examined for hormone secretion by in vitro culture and for hormone content by immunostaining. The results were correlated with the clinical findings. 40 % of the tumours (n = 263) secreted at least one of the gonadotropins alone, 8 % (n = 53) exhibited various patterns of anterior pituitary hormones, whilst the remaining 52 % of tumours were not associated with any hormone. In the secretory tumours, immunostaining revealed only a few scattered hormone-containing cells (5 to 15 %). Mild hyperprolactinaemia was observed in some cases, presumably because of pressure effects of the tumours. The majority of the patients suffered clear cut hypopituitarism (p < 0.05). Pre-operatively, gonadotropin hypersecretion was observed in 3 cases, but only one of these secreted hormones in culture. Interestingly, a higher proportion of tumours removed from patients with hypopituitarism showed secretory activity in vitro than those tumours removed from patients showing no hormonal dysfunction or hyperprolactinaemia. We conclude that the term "gonadotropinoma" to describe functionless pituitary tumours associated with LH and/or FSH secretion is a misnomer, because the presence of LH and/or FSH confirmed by in vitro methods in the present series is a result of only a few scattered cells. We suggest that primary pituitary tumour cells differentiate into a secretory type (transdifferentiation), possibly in response to altered serum hormone levels such as decreased steroids. Further work is required to identify the factors which trigger the altered cells' characteristics.

Adenoma↗
PubMed2005

An automated robotic approach with redundant navigation for minimal invasive extended transsphenoidal skull base surgery.

BACKGROUND: The aim of this work was to determine the feasibility of a robotic-assisted and fully automated approach to the sphenoid sinus. An image-guided robotic system was designed to address potential human errors in performing transsphenoidal sinus surgery by combining the reproducible accuracy of a robotic system with standard computer navigation. METHODS: A six-degrees of freedom robotic assistance system and an opto-electrical navigation system were combined for image-guided assistance with redundantly controlled robotics. Newly designed endoscopic instruments for robotic surgery have been developed and are described. Telemanipulatory, as well as fully automated procedures, were tested on cadaveric heads as part of a preclinical trial. RESULTS: A fully automated sphenoidotomy as well as a telemanipulatory sphenoidectomy were performed successfully on cadaveric heads. Intraoperative performance, accuracy assessment studies, as well as possible sources of stereotactic offsets are described. The mean measured robotic reproducibility accuracy was 0.056 mm (range: 0.02 - 0.14 mm) and the mean overall navigated robotic accuracy, including all transformation and registration errors was 1.53 mm (range: 1.13 - 1.89 mm) respectively. CONCLUSION: A system for robot-guided surgery in combination with redundant navigational control was developed. It allows highly accurate maneuvers, performed either in a telemanipulation mode as master-slave system or in a fully automated fashion. A sphenoidectomy on cadaveric heads was performed in both telemanipulation and fully automated modes. The overall intraoperative accuracy was in the range of the resolution of the CT images and stereotactic offsets were caused mainly due to deflections of the endoscopic operating instrument.

Cadaver↗
PubMed2005

Immunopathology of primary hypophysitis: implications for pathogenesis.

The etiology of primary hypophysitis is still not fully elucidated. Histologically, primary hypophysitis includes three different main subtypes: lymphocytic (LYH), granulomatous (GRH), and xanthomatous (XH) hypophysitis. Clinical and laboratory findings suggest an autoimmune basis in primary hypophysitis. Controversy still exists about the composition of the inflammatory infiltrate and the relevant immunopathogenic effector mechanisms. Therefore, 21 cases of primary hypophysitis of different subtypes were analyzed with respect to the expression of lymphocyte and macrophage antigens as well as MHC class I and II molecules of the inflammatory infiltrate and the resident pituitary acinar cells. Lymphocyte infiltration in LYH (n = 15), but also in GRH (n = 4) and XH (n = 2), mainly consisted of T cells, while B cells were rare. Independent from the histopathologic subtype, T cell subsets showed equal ratios of CD4+ to CD8+ T cells. Highest numbers of activated CD8+ T cells were observed in LYH presenting during pregnancy, surrounding or even infiltrating preserved pituitary acinar cells. Moreover, an increased rate of activated CD8+ T cells correlated with a shorter duration of clinical symptoms. In LYH, aberrant expression of MHC class II antigens as well as overexpression of MHC class I molecules on pituitary cells were observed. Independent of the histologic subtype, macrophages mostly expressed markers of chronic activation and showed MHC class II positivity. LYH, GRH, and XH, although heterogeneous in their histologic appearance and in age distribution, exhibit a similar if not identical immunohistologic profile. It is highly likely that direct T cell-mediated cytotoxicity through CD8+ T cells, with the initial help of CD4+ T cells, is pivotal in the pathogenesis of primary hypophysitis, implicating a target autoantigen expressed by pituitary cells.

Adult↗
PubMed2005

Neurovascular relationship at the trigeminal root entry zone in persistent idiopathic facial pain: findings from MRI 3D visualisation.

BACKGROUND: Patients with atypical neuralgia or atypical facial pain have been surgically treated with microvascular decompression (MVD) of the trigeminal root entry zone (TREZ). There are no data regarding the sensitivity and specificity of a vessel-TREZ relationship as a cause of pain in patients with persistent idiopathic facial pain (PIFP) according to the definition given by the International Headache Society (IHS). METHODS: The TREZ was visualised by 3D CISS MRI in 12 patients with unilateral PIFP according to the IHS criteria. RESULTS: The frequency of artery-TREZ, vein-TREZ, or vessel (artery/vein)-TREZ contacts on the symptomatic and asymptomatic sides did not differ significantly. On the symptomatic side, vessel-TREZ contact was found in 58% of patients (sensitivity). On the asymptomatic side, vessel-TREZ contact was absent in 33% of patients (specificity). CONCLUSIONS: On the basis of the low sensitivity and specificity found in the present study, PIFP cannot be attributed to a vessel-TREZ contact, and therefore, pain relief after MVD cannot be expected.

Aged↗
PubMed2004

Impact of primary surgery on pituitary function in patients with non-functioning pituitary adenomas -- a study on 721 patients.

INTRODUCTION: The aim of this study was to define the impact of surgery on pituitary function in a large consecutive series of patients harbouring non-functioning pituitary adenomas. MATERIALS AND METHOD: Between December 1982 and December 2000, a total of 822 patients underwent primary surgery in the authors' department. In 721 cases a complete set of endocrinological data was available. Functions of the pituitary-gonadal, pituitary-thyroid and pituitary-adrenal axes were assessed immediately before surgery and again one week, 3 months and 1 year after the operation, utilizing standardized tests and commercially available assays. RESULTS: There was some degree of pre-operative hypopituitarism in 561 (85%) and 53 (86.3%) of the patients belonging to the transsphenoidal and the transcranial groups, respectively. Prior to transsphenoidal [transcranial] surgery, 163 (31%) [34 (55.7%)] of the patients had secondary adrenal deficiency, 463 (76.6%) [49 (89%)] had hypogonadism and 105 (19.1%) [14 (25.4%)] were hypothyroid. Preoperatively, prolactin levels were mildly elevated in 167 patients (25.3%), whereas 1 year after surgery, levels were elevated in only 5 patients. Permanent diabetes insipidus occurred in 4 patients, 2 from the transsphenoidal group (0.3%) and 2 from the transcranial group (3.2%). Following transsphenoidal surgery 110 (19.6%) of patients had normal pituitary function [versus 0% after transcranial surgery], 169 (30.1%) [6 (11.3%)] showed improvement, 274 (48.9%) [49 (73.7%)] had persistent deficits and 8 (1.4%) [8 (15%)] showed deterioration of pituitary function. DISCUSSION: These data indicate that transsphenoidal surgery for non-functioning pituitary adenomas in expert hands is, relatively, far less detrimental to patients compared with transcranial surgery. The latter carries a much greater risk of post-operative deterioration in pituitary function.

Adenoma↗
PubMed2004

Functional neuronavigation and intraoperative MRI.

Our concept of computer assisted surgery is based on the combination of intraoperative magnetic resonance (MR) imaging with microscope-based neuronavigation, providing anatomical and functional guidance simultaneously. Intraoperative imaging evaluates the extent of a resection, while the additional use of functional neuronavigation, which displays the position of eloquent brain areas in the operative field, prevents increasing neurological deficits, which would otherwise result from extended resections. Up to mid 2001 we performed intraoperative MR imaging using a low-field 0.2 Tesla scanner in 330 patients. The main indications were the evaluation of the extent of resection in gliomas, pituitary tumours, and in epilepsy surgery. Intraoperative MR imaging proved to serve as intraoperative quality control with the possibility of an immediate modification of the surgical strategy, i.e. extension of the resection. Integrated use of functional neuronavigation prevented increased neurological deficits. Compared to routine pre- or postoperative imaging being performed with high-Tesla machines, intraoperative image quality and sequence spectrum could not compete. This led to the development of the concept to adapt a high-field MR scanner to the operating environment, preserving the benefits of using standard microsurgical equipment and microscope-based neuronavigational guidance with integrated functional data, which was successfully implemented by April 2002. Up to the end of 2002, 95 patients were investigated with the new setup. Improved image quality, intraoperative workflow, as well as enhanced sophisticated intraoperative imaging possibilities are the major benefits of the high-field setup.

Brain Neoplasms↗
PubMed2004

Magnetic source imaging supports clinical decision making in glioma patients.

OBJECTIVE: This study addresses the potential utility of preoperative functional imaging with magnetoencephalography (MEG) for the selection of glioma patients who are likely to benefit from resective surgical treatment regarding postoperative morbidity. METHODS: One hundred and nineteen patients with gliomas adjacent to sensorimotor, visual and speech related brain areas were investigated preoperatively with a MAGNES II biomagnetometer. In each patient the pre-surgical evaluation was focussed on the visual, sensorimotor cortex and/or of the speech related brain areas. A grading system was then used according to the distance of the MEG activation sources to the nearest tumour border to determine the further treatment. The therapeutic options consisted in conservative treatment, stereotactic biopsy and/or a radiation and chemotherapy, substantial cytoreduction and the gross total removal of the lesion. RESULTS: From 119 investigated patients, 55 patients (46.2%) were not considered for surgery due to tumour invasion to functional cortex. Sixty four patients (53.8%) were chosen for resective surgery. In the surgical group only four patients (6.2%) suffered from neurological deterioration. CONCLUSIONS: Magnetic source imaging (MSI) proved to be a valuable help in the clinical decision making process of lesions adjacent to functional important brain areas. The relative high number of patients in whom MSI warns of the postoperative crippling sequelae may lead to a better selection of patients who benefit from resective surgery. This method may help to find the patients for whom conservative treatment seems to be more favourable concerning quality of life in the surviving time.

Adolescent↗
PubMed2004

Adaptation of a hexapod-based robotic system for extended endoscope-assisted transsphenoidal skull base surgery.

OBJECTIVE: To adapt a hexapod-based robotic system for use in extended endoscope-assisted transsphenoidal skull base surgery. METHODS: A robotic system (Evolution 1, Universal Robot Systems, Schwerin, Germany) based on a hexapod design with an attached seventh axis is used as instrument holder. The instrument interface is operated via a joystick control. An endoscope is applied to the instrument interface, which is tracked by a navigation system (Stealth, Medtronic, USA). RESULTS: The instrument holder was modified so that it could be applied in transsphenoidal surgery. Furthermore, translation and pivoting movements of the system were implemented, also a quick change between microscope and robotic-controlled endoscope was made possible. After extensive phantom testing two patients with large invasive pituitary adenomas were operated on using the robotic endoscope assistance during transsphenoidal surgery. The robotic assistance allowed the use of two additional instruments under endoscopic view. For example, drilling, suctioning, application of punches, as well as microsurgical tumor removal could be performed under endoscopic view. CONCLUSION: A robotic system could be adapted for use in endoscope-assisted transsphenoidal skull base surgery allowing simultaneous use of two instruments under endoscopic view. This opens new possibilities to extend transsphenoidal skull base surgery.

Adenoma↗
PubMed2004

[Primary loss of consciousness and amnesia in subarachnoid hemorrhage--a quantitative study].

Subarachnoid hemorrhages (SAH) being sudden events affecting the brain in a rather wide-spread fashion are apt to induce loss of consciousness (LOC) and amnesia. The aim of the present study was to collect data on their frequency and extent. To this end we examined 48 patients at a mean of one year post-onset. Two thirds of them reported anterograde and an additional 17% retrograde amnesia; in 40% LOC (median 6 minutes) was observed. The durations were extremely skewed towards shorter times with a median of 2.7 days for anterograde and 1.3 days for retrograde amnesia who--with a single exception--were markedly shorter than anterograde amnesia. Summing up, a significant proportion of all SAH suffered LOC and amnesia occurred in the majority of cases. SAH therefore are events which with respect to LOC and amnesia bear some resemblance with closed head injuries. Exact observation and history taking may disclose important data on their severity and possible sequelae.

Adult↗
PubMed2004

Delayed facial nerve paresis following acoustic neuroma resection and postoperative vasoactive treatment.

OBJECT: Delayed facial nerve paresis is a well known clinical phenomenon following acoustic neuroma surgery, typically occurring early during the postoperative course. The clinical course of the delayed facial nerve paresis and intraoperative electromyographic (EMG) signals were evaluated in a subgroup of patients who underwent vasoactive treatment for preservation of hearing and developed secondary deterioration after termination of treatment. METHODS: Between 1990 and 2001 seven patients were identified who received vasoactive treatment for preservation of hearing and developed a delayed facial nerve paresis after termination of medication. Intraoperative facial nerve EMG activity was analyzed in six patients. RESULTS: All patients developed a delayed facial nerve paresis between 2-5 days following termination of a 10 day treatment consisting of HES and nimodipine. Medication was re-initiated and the facial nerve paresis improved in all patients. In two patients intraoperative EMG signals revealed "A-trains" waveform patterns, which are highly suggestive for an immediate postoperative facial nerve paresis, whereas in four patients no pathognomonic EMG patterns could be recorded. CONCLUSIONS: The delayed onset of a facial paresis following termination of vasoactive treatment points to a disturbed microcirculation of the nerve as the main pathophysiological feature. Two groups could be identified on the basis of intraoperative EMG activity. In one group with presence of "A-trains" medication apparently masked the onset of an immediate postoperative facial nerve deficit. Four patients without "A-trains" did not develop a typical delayed facial nerve paresis during vasoactive treatment, but thereafter. The time lag between termination of treatment and onset of a delayed palsy points to a protective effect due to improved microcirculation.

Adult↗
PubMed2003

[Facial nerve schwannoma in the inner auditory canal and geniculate ganglion].

BACKGROUND: Schwannoma of the vestibular nerve is the most common tumor found in the inner auditory canal. If a schwannoma of the facial nerve is found unexpectedly during surgery, the original surgical plan may have to be changed. In our series, we describe the symptoms, diagnostic procedures and therapy of this infrequent, benign tumor. In particular, we want to analyse the influence of diagnostic techniques, such as magnetic resonance tomography and electrophysiology, on the diagnosis of these tumors. PATIENTS: Between 1975 and 2001, we diagnosed 17 cases of facial nerve schwannoma in the inner auditory canal or the geniculate ganglion. All patients were treated surgically. In 16 cases, we used the enlarged middle fossa approach and in the remaining patient the translabyrinthine approach was used. RESULTS: In 11 cases, the facial nerve could be saved but in six the nerve had to be rebuilt with a transplant. During the first years of our study, palsy of the facial nerve was a frequent finding. In the later years, a hearing impairment and tinnitus became the most frequent symptoms. CONCLUSIONS: Advances in magnetic resonance imaging have, in many cases, facilitated the differentiation between schwannomas of the facial nerve and the vestibular nerve over the last years. Signal enhancement at the geniculate ganglion is important for the diagnosis of facial nerve schwannoma. In individual cases, we found significant findings using electrophysiological procedures. In three cases, the temporal delay was elongated. Based on these findings, the therapeutic procedures can be discussed together with the patients.

Adolescent↗