Pituitary insufficiency after operation of supratentorial intra- and extraaxial tumors outside of the sellar–parasellar region?

Recent studies investigating pituitary function after non-sellar brain tumor surgery showed that up to 38.2% of patients have pituitary insufficiency (PI). It has been assumed that the operation causes the PI, but preoperative hormone testing, which would have been necessary to prove this assumption, was not performed. The objective of this study is to answer the question if indeed microsurgery is the culprit of PI in patients with operatively treated non-sellar brain tumors. In this prospective trial, 54 patients with supratentorial non-sellar tumors were included. The basal levels of cortisol, prolactin, testosterone, estrogen, IGF-1, fT3, fT4, STH, TSH, ACTH, FSH, and LH were recorded preoperatively on days 1 and 7 after surgery. If basal hormone screening revealed an abnormality, a releasing hormone assay was performed. Before surgery, 24 of the 54 patients (44.4%) already had PI. Additional 25 patients showed either hypocortisolism or hypothyreoidism. As those patients had been pre-treated with dexamethasone and l-thyroxine, these findings were considered not to represent PI but drug effects. Hormone testing on days 1 and 7 after surgery revealed no changes. With 44.4% PI is a frequent finding in brain tumor patients already before surgery. The factors causing preoperative PI remain yet to be identified. The endocrine results after surgery are unchanged which rules out that surgery is the cause of PI

The role of neuronavigation in intracranial endoscopic procedures

In occlusive hydrocephalus, cysts and some ventricular tumours, neuroendoscopy has replaced shunt operations and microsurgery. There is an ongoing discussion if neuronavigation should routinely accompany neuroendoscopy or if its use should be limited to selected cases. In this prospective clinical series, the role of neuronavigation during intracranial endoscopic procedures was investigated. In 126 consecutive endoscopic procedures (endoscopic third ventriculostomy, ETV, n = 65; tumour biopsy/resection, n = 36; non-tumourous cyst fenestration, n = 23; abscess aspiration and hematoma removal, n = 1 each), performed in 121 patients, neuronavigation was made available. After operation and videotape review, the surgeon had to categorize the role of neuronavigation: not beneficial; beneficial, but not essential; essential. Overall, neuronavigation was of value in more than 50% of the operations, but its value depended on the type of the procedure. Neuronavigation was beneficial, but not essential in 16 ETVs (24.6%), 19 tumour biopsies/resections (52.7%) and 14 cyst fenestrations (60.9%). Neuronavigation was essential in 1 ETV (2%), 11 tumour biopsies/resections (30.6%) and 8 cyst fenestrations (34.8%). Neuronavigation was not needed/not used in 48 ETVs (73.9%), 6 endoscopic tumour operations (16.7%) and 1 cyst fenestration (4.3%). For ETV, neuronavigation mostly is not required. In the majority of the remaining endoscopic procedures, however, neuronavigation is at least beneficial. This finding suggests integrating neuronavigation into the operative routine in endoscopic tumour operations and cyst fenestrations

Microsurgery can cure most intracranial dural arteriovenous fistulae of the sinus and non-sinus type

There is consensus that intracranial dural arteriovenous fistulae (dAVF) with direct (non-sinus-type) or indirect (sinus-type) retrograde filling of a leptomeningeal vein should be treated due to the high risk of neurological deficits and hemorrhage. No consensus exists on treatment modality (surgery and/or embolization) and, if surgery is performed, on the best surgical strategy. This series aims to evaluate the role of surgery in the management of aggressive dAVFs. Forty-two patients underwent surgery. Opening and packing the sinus with thrombogenic material was performed in 9 of the 12 sinus-type dAVFs. In two sinus-type fistulae of the cavernous sinus and 1 of the torcular, microsurgery was used as prerequisite for subsequent embolization by providing access to the sinus. In the 30 non-sinus-type dAVFs, surgery consisted of interruption of the draining vein at the intradural entry point. In 41 patients undergoing 43 operations, elimination of the dAVF was achieved (97.6%). In one case, a minimal venous drainage persisted after surgery. The transient surgical morbidity was 11.9% (n = 5) and the permanent surgical morbidity 7.1% (n = 3). Our surgical strategy was to focus on the arterialized leptomeningeal vein in the non-sinus-type and on the arterialized sinus segment in the sinus-type dAVFs allowing us to obliterate all but one dAVF with a low morbidity rate. We therefore propose that microsurgery should be considered early in the treatment of both types of aggressive dAVFs. In selected cases of cavernous sinus dAVFs, the role of microsurgery is reduced to that of an adjunct to endovascular therapy

2-Octyl-cyanoacrylate for wound closure in cervical and lumbar spinal surgery

It is claimed that wound closure with 2-octyl-cyanoacrylate has the advantages that band-aids are not needed in the postoperative period, that the wound can get in contact with water and that removal of stitches is not required. This would substantially enhance patient comfort, especially in times of reduced in-hospital stays. Postoperative wound infection is a well-known complication in spinal surgery. The reported infection rates range between 0% and 12.7%. The question arises if the advantages of wound closure with 2-octyl-cyanoacrylate in spinal surgery are not surpassed by an increase in infection rate. This study has been conducted to identify the infection rate of spinal surgery if wound closure was done with 2-octyl-cyanoacrylate. A total of 235 patients with one- or two-level surgery at the cervical or lumbar spine were included in this prospective study. Their pre- and postoperative course was evaluated. Analysis included age, sex, body mass index, duration and level of operation, blood examinations, 6-week follow-up and analysis of preoperative risk factors. The data were compared to infection rates of similar surgeries found in a literature research and to a historical group of 503 patients who underwent wound closure with standard skin sutures after spine surgery. With the use of 2-octyl-cyanoacrylate, only one patient suffered from postoperative wound infection which accounts for a total infection rate of 0.43%. In the literature addressing infection rate after spine surgery, an average rate of 3.2% is reported. Infection rate was 2.2% in the historical control group. No risk factor could be identified which limited the usage of 2-octyl-cyanoacrylate. 2-Octyl-cyanoacrylate provides sufficient wound closure in spinal surgery and is associated with a low risk of postoperative wound infection

Functional Neuronavigation: Comparison of spatial congruence between fMRI and electrocortical stimulation in central region tumor surgery

Titelblatt und Inhaltsverzeichnis 1\. Einleitung 2\. Fragestellung 3\. Material und Methodik 3.1 Patientensample 3.2 Neurologische Untersuchung und Dokumentation 3.3 Untersuchungstechniken und Untersuchungsablauf 3.4 Statistik und Auswertung 4\. Ergebnisse 4.1 Patientendaten 4.2 Vergleich der Untersuchungsergebnisse am Patientenbeispiel 4.3 Ergebnisse der präoperativen funktionellen MRT (fMRT) 4.4 Ergebnisse der Neuronavigation 4.5 Ergebnisse des intraoperativen neurophysiologischen Monitorings 4.6 Neurologische Untersuchungsergebnisse 4.7 Einflüsse der räumlichen Tumorausdehnung und dessen Lage unter Kortexniveau auf die Untersuchungsergebnisse 4.8 Korrelation der zeitdifferenz zwischen präoperativ erhobenen fMRT-Daten und Operationsbeginn 5\. Diskussion 6\. Zusammenfassung 7\. Literaturverzeichnis 8\. Abkürzungsverzeichnis 9\. Abbildungsverzeichnis 10\. Tabellenverzeichnis 11\. Anhang Danksagungen Erklärung LebenslaufHintergrund: Die operative Behandlung von Läsionen in der unmittelbaren Nähe des Sulcus centralis stellt den Neuro-chirurgenvor eine besondere Herausforderung. Zwar korreliert eine radikale Tumorresektion mit einer erhöhten Lebenserwartung, aufgrund der funktionellen Bedeutung der Zentralregion besteht jedoch die Gefahr einer erhöhten Operationsmorbidität. Deshalb fällt der prä-und intraoperativen Identifikation kortikaler Funktionsareale eine ent-scheidendeBedeutung zu. Verschiedene Techniken zur Darstellung der patientenspezifischen funktionellen und morphologischen Topo- graphiehaben es in den letzten Jahren ermöglicht, sowohl präoperativ nicht- invasiv, als auch direkt intraoperativ den Sulcus centralis mit den angrenzenden Gyrizu identifizieren. Hierzu zählen u.a. die Techniken der funktionellen Bildgebung, wie der fMRT sowie intraoperativ die Ableitung somatosensibelevozierter Potenziale oder die direkte kortikale Stimulation (MCS) des Motorkortex. Methodik: Ziel dieser Studie war es, die räumliche Auflösung der fMRT im Bereich des primären motorischen Kortex (fingertapping Paradigma, BrainVoyager®2000) mit der intraoperativen IOM- Ortung(kombinierte SEP-Phasenumkehr / MCS-Mapping, Viasys Endeavor®) zu vergleichen. Hierzu wurden die fMRT-Daten und die IOM- Stimulationskoordinatenvon 21 Patienten (12 Männer, 9 Frauen, mittleres Alter: 56,2 Jahre, 13 präzentraleTx, 8 postzentrale Tx) mit Hilfe eines rahmenlosen Navigationsverfahrens (Mayfield ACCISS II®) fusioniert und bezüglich ihrer Ortsgenauigkeit korreliert. Mit Hilfe der Abstandsberechnung nach Euklid wurde die Abweichung der Koordinaten (fMRT max.; fMRT max.-Projektionauf Kortexniveau; MCS max. Kortexoberfläche) zueinander berechnet. Die statistische Korrelation wurde nach Pearson und Spearmanermittelt. Ergebnisse: Mit Hilfe der Kombination aus SEP-Phasenumkehr und des MCS-Mappingkonnte der primäre motorische Kortex, bzw. der Sulcus centralis in 100% der Fälle (21/21) identifiziert werden.Die fMRT lokalisierte in allen 21 Fällen die Lage der motorischen Funktion (korreliert zum intraoperativen Stimulationserfolg) korrekt frontal, bzw. parietal zur Läsion. Jedoch zeigte der Punkteabstand im Raum zwischen den Ober-flächenkoordinatender MCS (Hand-/Fingerareal) und denen der fMRT (bzw. der fMRT-Projektion) eine räumliche Abweichungen zwischen 6,8 und 27,5 mm. In 5 Fällen betrug die Diskordanzweniger als 10 mm, in 15 Fällen zwischen 10 und 20 mm und in einem Fall mehr als 20 mm. Ein Zusammenhang zwischen der Tumorart, dem *Tumor-volumenincl. seiner Ausdehnung unter Kortexniveau sowie der prä-operativen neurologischen Symptomatik und dem Ausmaßder räum-lichenAbweichung zwischen MCS und fMRT ließsich statistisch nicht nachweisen (*r<0,27 ). Schlussfolgerungen: Das IOM muss weiterhin als Goldstandard für die Lokalisation motorisch eloquenter Hirnareale bei Eingriffen in der Zentralregion angesehen werden. Zwar kann die fMRT bereits präoperativ wichtige Informationen über die individuelle funktionelle Topographie geben die mit 10 bis 20 mm Abweichung zur direkten Kortexstimulation jedoch schlechte Ortsauflösung schränkt ihre unkritische Verwendung für die Funktionelle Navigation ohne eine intraoperative neurophysiologische Kontrolle deutlich ein. Nach Ansicht der Autoren muss daher eine rein fMRT-gesteuerteTumorresektion zum aktuellen Zeitpunkt noch abgelehnt werden.Background: The surgical treatment of lesions in or around the central region confronts the neurosurgeon with a great challenge. Radical tumor resection leads to a better outcome but it also bears the risk of postoperative neurological deficit due to the functional importance of the central region. Throughout the last couple of years different techniques made it possible to identify the patient s specific functional and anatomical topography. The central sulcus and the adjacent gyri can be identified before surgery non- invasively and directly during surgery. Among other technical methods functional visualization through fMRI as well as electrocortical stimulation of the central region during surgery are part of these techniques. Methods: The intention of this study was to compare the spatial congruence between fMRI-data of the central region (finger tapping paradigm, Brain Voyager® 2000) and the intraoperative neurophysiological monitoring (combined SEP-phase reversal / MCS-mapping, Viasys Endeavor®). To accomplish this goal the fMRI and IOM- data of 21 patients (12 men and 9 women, mean age: 56,2 years, 13 precentral and 8 postcentral lesions) were implemented into a neuronavigation system (Mayfield Acciss II) and correlated regarding the spatial congruence. The distances between the coordinates (fMRI max.; fMRI max. -projection to the cortex surface; MCS max. of the cortex surface) were calculated with the formula of Euclid. The statistical correlation was determined by the methods of Pearson and Spearman. Results: Through SEP-phase reversal and MCS-mapping the primary motor cortex as well as the central sulcus was identified in 100% of the cases (21/21). The fMRI localized the motor function (correlated to the intraoperative stimulation) in 21 cases in correct frontal respectively parietal position to the lesion. The data analysis showed that the visualized anatomical topographic results received from fMRI (respectively fMRI- projection) deviated from those received via IOM-data (hand-/finger-region) between 6,8 and 27,5mm. In five cases the difference was less than 10mm, in 15 cases between 10 and 20mm, and in one case more than 20mm. A coherence between the tumor dignity, the *tumor volume (including its expansion under the cortex surface) as well as the neurological status before surgery and the spatial deviation between MCS and fMRI has been ruled out statistically (*r< 0,27). Conclusion: The IOM-technique still has to be considered as the gold standard for the localization of eloquent functional motor regions in central region tumor surgery. FMRI can provide important information of the individual functional topography before surgery. Considering the spatial incongruence between 10 and 20 mm compared to the direct cortex stimulation this leads to an insufficient spatial resolution and to the limitation of Functional Neuronavigation . An uncritical implementation without data confirmation through IOM during surgery should be avoided. Following the authors opinion exclusive functional MRI guided central region tumor surgery has to be rejected nowadays

Color filters: When “optimal” is not optimal

It is well known that many more than three or four spectral measurements are required for accurate measurement of color. Previous work has shown seven to ten measurements can yield accurate results on average, but with significant numbers of errors above the threshold of obvious visual detection. Furthermore, the filters used for these measurements are very difficult to fabricate. We show that such filters are not needed and, in fact, have much poorer performance, in perceptual quality measured in ΔEab, than simple narrow-band filters. This is especially true in the presence of Poisson noise at a level common in current digital cameras. In realistic Poisson noise, our filter sets of up to 12 filters allow average ΔEab values around 0.5, with maximum errors below 3