Cranial and Spinal Metastasis of a Nonfunctioning Pituitary Adenoma: Report of a Case

Pituitary carcinoma is a rare disease with surgical, radiotherapeutic, and chemotherapeutic treatment options. We present the case of a female patient diagnosed with a nonfunctioning pituitary adenoma who underwent several surgical procedures, radiations, and chemotherapeutic treatments with various substances. Sixteen years after the first diagnosis, a cranial and spinal metastatic spread of the tumor occurred. We opted for an individual therapy based on anecdotal evidence. Unfortunately, the recommended off-label treatment with a somatostatin analog substance was never given due to bureaucratic delays. This case report is about the challenging aspects of individual decision-making in rare neurosurgical diseases.

Variants of Oxidized Regenerated Cellulose and Their Distinct Effects on Neuronal Tissue

Based on oxidized regenerated cellulose (ORC), several hemostyptic materials, such as Tabotamp^®, Equicel^® and Equitamp^®, have been developed to approach challenging hemostasis in neurosurgery. The present study compares ORC that differ in terms of compositions and properties, regarding their structure, solubility, pH values and effects on neuronal tissue. Cytotoxicity was detected via DNA-binding fluorescence dye in Schwann cells, astrocytes, and neuronal cells. Additionally, organotypic hippocampal slice cultures (OHSC) were analyzed, using propidium iodide, hematoxylin-eosin, and isolectin B₄ staining to investigate the cellular damage, cytoarchitecture, and microglia activation. Whereas Equicel^® led to a neutral pH, Tabotamp^® (pH 2.8) and Equitamp^® (pH 4.8) caused a significant reduction of pH (p < 0.001). Equicel^® and Tabotamp^® increased cytotoxicity significantly in several cell lines (p < 0.01). On OHSC, Tabotamp^® and Equicel^® led to a stronger and deeper damage to the neuronal tissue than Equitamp^® or gauze (p < 0.01). Equicel^® increased strongly the number of microglia cells after 24 h (p < 0.001). Microglia cells were not detectable after Tabotamp^® treatment, presumably due to an artifact caused by strong pH reduction. In summary, our data imply the use of Equicel^®, Tabotamp^® or Equitamp^® for specific applications in distinct clinical settings depending on their localization or tissue properties.

Variability in the distance from the end of the gray matter to the end of the conus medullaris: a case-triggered histological investigation

OBJECTIVE

The background for this investigation was the dramatic course of a 14-year-old girl with a spontaneous hemorrhage in the area of the conus medullaris resulting in a complete cross-sectional syndrome with bladder and bowel dysfunction. Despite immediate surgical treatment, the patient showed close to no postoperative improvement. Subsequent histopathological examination of the removed masses revealed a cavernoma. To better understand the link between the site and symptoms of conus medullaris lesions, the authors performed a literature search and then histological examination of the conus medullaris of 18 cadaveric specimens from body donors.

METHODS

After a literature search regarding the histological features of the structure of the conus medullaris did not lead to satisfying results, the authors performed histological examination of the conus medullaris in 18 cadaveric specimens from body donors. The largest (a) and smallest (b) diameters of the conus medullaris were measured, noting individual variations in the distance from the caudal ending of the gray matter to the macroscopically visible end of the conus medullaris. Correlations of these differences with sex, body height, gray matter transverse diameter, and cross-sectional area at the end of the gray matter were analyzed.

RESULTS

Gray matter displayed in the form of a butterfly figure was found along almost the entire length of the conus medullaris. The specific slide containing the end of the gray matter was noted. The distance between the caudal ending of the gray matter in the conus and the macroscopical end of the conus medullaris was defined as the gray matter to cone termination (GMCT) distance. There were great individual variations in the distance from the caudal ending of the gray matter to the macroscopically visible end of the conus medullaris. Analysis of the correlations of these differences with sex, body height, gray matter transverse diameter, and cross-sectional area at the end of the gray matter showed no significant sex-specific differences in the GMCT distance. Patient body height and transverse diameter at the end of the gray matter were found to be correlated positively with the GMCT distance. Moreover, greater height also correlated positively with the cross-sectional area at the end of the gray matter.

CONCLUSIONS

This report is, to the authors' knowledge, the first published description of the histological structure of the conus medullaris and can serve as the basis for a better understanding of neurological deficits in patients with a conus medullaris syndrome. Findings that gray matter can be detected far into the conus medullaris, with large individual differences in the endpoint of the gray matter, are important for operative care of intramedullary masses and vascular malformations in this area. It is therefore important to use electrophysiological monitoring during these operations.

Prophylactic nimodipine treatment for hearing preservation after vestibular schwannoma surgery: study protocol of a randomized multi-center phase III trial-AkniPro 2

Background

A previously performed phase III trial on 112 subjects investigating prophylactic nimodipine treatment in vestibular schwannoma (VS) surgery showed no clear beneficial effects on preservation of facial and cochlear nerve functions, though it should be considered that protection of facial nerve function was the primary outcome. However, the risk for postoperative hearing loss was halved in the nimodipine group compared to the control group (OR 0.49; 95% CI 0.18–1.30; p = 0.15). Accordingly, this phase III extension trial investigates the efficacy and safety of prophylactic nimodipine for hearing preservation in VS surgery.

Methods

This is a randomized, multi-center, two-armed, open-label phase III trial with blinded expert review and two-stage with interim analysis. Three hundred thirty-six adults with the indication for microsurgical removal of VS (Koos I–IV) and serviceable preoperative hearing (Gardner-Robertson scale (GR) 1–3) are assigned to either the therapy (intravenous nimodipine 1–2 mg/h from the day before surgery until the fifth postoperative day and standard of care) or the control group (surgery only and standard of care). The primary endpoint of the trial is postoperative cochlear nerve function measured before discharge according to GR 1–3 versus GR 4–5 (binary). Hearing function will be determined by pre- and postoperative audiometry with speech discrimination, which will be evaluated by a blinded expert reviewer. Furthermore, patient-reported outcomes using standardized questionnaires will be analyzed.

Discussion

Prophylactic parenteral nimodipine treatment may have a positive effect on hearing preservation in VS surgery and would improve patient’s quality of life. Further secondary analyses are planned. Except for dose-depending hypotension, nimodipine is known as a safe drug. In the future, prophylactic nimodipine treatment may be recommended as a routine medication in VS surgery. VS can be considered as an ideal model for clinical evaluation of neuroprotection, since hearing outcome can be classified by well-recognized criteria. The beneficial effect of nimodipine may be transferable to other surgical procedures with nerves at risk and may have impact on basic research.

Trial registration

EudraCT 2019-002317-19, DRKS00019107. 8th May 2020.

Volumetry and Surgical Grading Systems for Vestibular Schwannoma Size Assessment and their Relationship to Postoperative Facial Nerve Function

BACKGROUND AND STUDY AIMS

 Treatment modalities in vestibular schwannoma (VS) are difficult to compare since different techniques for size measurements are used. The purpose of this study was to evaluate the relation between different tumor size grading systems regarding their compatibility as well as the relationship to facial nerve outcome facilitating comparisons of different studies.

MATERIAL AND METHODS

 In this retrospective study, preoperative magnetic resonance imaging of 100 patients with surgically treated VS was evaluated regarding total tumor volume and anatomical extension based on the Koos and Samii classification, as well as volumetric and maximal diameter measures. Three-dimensional constructive interference in steady state (3D-CISS) and T1 postcontrast volumetric interpolated breath-hold examination (VIBE) sequences were used. Facial nerve function was evaluated according to the House-Brackmann (HB) scale 6 months following complete tumor removal via the retrosigmoid approach.

RESULTS

 Tumor size showed a moderate influence on postsurgical facial nerve function with correlations not exceeding 0.4. Severe palsy was observed mainly in patients with large tumors with Koos grade 4, Samii grade 4b, respectively a volume of at least 6 cm³ or a maximum diameter of 2.4 cm for HB ≥ 3 and a volume of 7.5 cm³ and maximum diameter of 3.2 cm for HB ≥ 4. In regard to volumetry, the Koos and Samii grading systems were highly comparable, whereas the maximal diameter showed consistently lower correlation values.

CONCLUSIONS

 The results of our study allow direct comparison of studies on surgery versus radiotherapy of VS. The data allow for translation of tumor sizes based on different grading systems. Comparison of microsurgical, radiotherapeutic and radiosurgical approaches should concentrate on patients with large tumors. Whereas smaller tumors were rarely associated with severe facial palsy, large tumors did not exclude the possibility of weak or no palsy 6 months after surgery.

Optimized preoperative determination of nerve of origin in patients with vestibular schwannoma

In vestibular schwannoma (VS) patients hearing outcome and surgery related risks can vary and depend on the nerve of origin. Preoperative origin differentiation between inferior or superior vestibular nerve may influence the decision on treatment, and the selection of optimal treatment and counselling modalities. A novel scoring system based on functional tests was designed to predict the nerve of origin for VS and was applied to a large number of consecutive patients. A prospective, double blind, cohort study including 93 patients with suspected unilateral VS was conducted at a tertiary referral centre. Preoperatively before tumor resection a functional test battery [video head-impulse test (vHIT) of all semicircular canals (SCC)], air-conducted cervical/ocular vestibular evoked myogenic potential tests (cVEMP, oVEMP), pure-tone audiometry, and speech discrimination was applied. Sensitivity and specificity of prediction of intraoperative finding by a preoperative score based on vHIT gain, cVEMP and oVEMP amplitudes and asymmetry ratios was calculated. For the prediction of inferior vestibular nerve origin, sensitivity was 73% and specificity was 80%. For the prediction of superior vestibular nerve origin, sensitivity was 60% and specificity was 90%. Based on the trade-off between sensitivity and specificity, optimized cut-off values of - 0.32 for cVEMP and - 0.11 for oVEMP asymmetry ratios and vHIT gain thresholds of 0.77 (anterior SCC), 0.84 (lateral SCC) and 0.80 (posterior SCC) were identified by receiver operator characteristic curves. The scoring system based on preoperative functional tests improves prediction of nerve of origin and can be applied in clinical routine.

Epithelioid Hemangioendothelioma in the Area of the Neurovascular Bundle of the Upper Arm Mimicking a Schwannoma of the Ulnar Nerve

Epithelioid hemangioendothelioma (EH) is a rare vascular malignant sarcoma. To date, there are only two published case reports of EH mimicking nerve sheath tumors of a peripheral nerve. A 41-year-old woman presented with a painful node on the inside of the upper arm and motor deficits of the ulnar nerve. Magnetic resonance imaging (MRI) follow-up and neurosonography revealed a slowly progressive, contrast-enhancing tumor in the area of the neurovascular bundle. A schwannoma of the ulnar nerve was suspected. At surgery, the tumor was adherent to the brachial artery, but not to nerves. Pathology revealed an EH. EH may mimic a nerve sheath tumor and should be taken into consideration, especially because of its potential for metastasis and fatal progression.

Glycation of benign meningioma cells leads to increased invasion

Meningiomas are the most common non-malignant intracranial tumors. Like most tumors, meningiomas prefer anaerobic glycolysis for energy production (Warburg effect). This leads to an increased synthesis of the metabolite methylglyoxal (MGO). This metabolite is known to react with amino groups of proteins. This reaction is called glycation, thereby building advanced glycation endproducts (AGEs). In this study, we investigated the influence of glycation on two meningioma cell lines, representing the WHO grade I (BEN-MEN-1) and the WHO grade III (IOMM-Lee). Increasing MGO concentrations led to the formation of AGEs and decreased growth in both cell lines. When analyzing the influence of glycation on adhesion, chemotaxis and invasion, we could show that the glycation of meningioma cells resulted in increased invasive potential of the benign meningioma cell line, whereas the invasive potential of the malignant cell line was reduced. In addition, glycation increased the E-cadherin- and decreased the N-cadherin-expression in BEN-MEN-1 cells, but did not affect the cadherin-expression in IOMM-Lee cells.

THC Reduces Ki67-Immunoreactive Cells Derived from Human Primary Glioblastoma in a GPR55-Dependent Manner

Glioblastoma (GBM) is the most frequent malignant tumor of the central nervous system in humans with a median survival time of less than 15 months. ∆⁹-Tetrahydrocannabinol (THC) and cannabidiol (CBD) are the best-characterized components of Cannabis sativa plants with modulating effects on cannabinoid receptors 1 and 2 (CB₁ and CB₂) and on orphan receptors such as GPR18 or GPR55. Previous studies have demonstrated anti-tumorigenic effects of THC and CBD in several tumor entities including GBM, mostly mediated via CB₁ or CB₂. In this study, we investigated the non-CB₁/CB₂ effects of THC on the cell cycle of GBM cells isolated from human tumor samples. Cell cycle entry was measured after 24 h upon exposure by immunocytochemical analysis of Ki67 as proliferation marker. The Ki67-reducing effect of THC was abolished in the presence of CBD, whereas CBD alone did not cause any changes. To identify the responsible receptor for THC effects, we first characterized the cells regarding their expression of different cannabinoid receptors: CB₁, CB₂, GPR18, and GPR55. Secondly, the receptors were pharmacologically blocked by application of their selective antagonists AM281, AM630, O-1918, and CID16020046 (CID), respectively. All examined cells expressed the receptors, but only in presence of the GPR55 antagonist CID was the THC effect diminished. Stimulation with the GPR55 agonist lysophosphatidylinositol (LPI) revealed similar effects as obtained for THC. The LPI effects were also inhibited by CBD and CID, confirming a participation of GPR55 and suggesting its involvement in modifying the cell cycle of patient-derived GBM cells.

Management of transmodiolar and transmacular cochleovestibular schwannomas with and without cochlear implantation

Introduction

Hearing rehabilitation with cochlear implants has attracted increasing interest also for patients with cochleovestibular schwannoma. The authors report their experience with the surgical management of tumors with rare transmodiolar or transmacular extension and outcomes after cochlear implantation (CI).

Methods

This retrospective case series included nine patients with either primary intralabyrinthine tumors or secondary invasion of the inner ear from the internal auditory canal. The primary endpoint with CI, performed in six patients, was word recognition score at 65 dB SPL (sound pressure level). Secondary endpoints were intra- and postoperative electrophysiological parameters, impedance measures, the presence of a wave V in the electrically evoked (via the CI) auditory brainstem responses, the specifics of postoperative CI programming, and adverse events.

Results

Hearing rehabilitation with CI in cases of transmodiolar tumor growth could be achieved only with incomplete tumor removal, whereas tumors with transmacular growth could be completely removed. All six patients with CI had good word recognition scores for numbers in quiet conditions (80–100% at 65 dB SPL, not later than 6 to 12 months post CI activation). Four of these six patients achieved good to very good results for monosyllabic words within 1–36 months (65–85% at 65 dB SPL). The two other patients, however, had low scores for monosyllables at 6 months (25 and 15% at 65 dB SPL, respectively) with worsening of results thereafter.

Conclusions

Cochleovestibular schwannomas with transmodiolar and transmacular extension represent a rare entity with specific management requirements. Hearing rehabilitation with CI is a principal option in these patients.

Video online

The online version of this article (10.1007/s00106-020-00919-9) includes a video (2D and 3D versions) of the described surgical technique. Article and supplementary material are available at www.springermedizin.de. Please enter the title of the article in the search field, the supplementary material can be found under “Ergänzende Inhalte”.

Validation of the Hamilton Program for Schizophrenia Voices Questionnaire: Associations with emotional distress and wellbeing, and invariance across diagnosis and sex

BACKGROUND

Voice-hearing is a transdiagnostic experience with evident negative effects on patients. Good quality measurement is needed to further elucidate the nature, impact and treatment of voice-hearing experiences across patient groups. The Hamilton Program for Schizophrenia Voices Questionnaire (HPSVQ) is a brief self-report measure which requires further psychometric evaluation.

METHODS

Using data from a transdiagnostic sample of 401 adult UK patients, the fit of a conceptual HPSVQ measurement model, proposing a separation between physical and emotional voice-hearing characteristics, was tested. A structural model was examined to test associations between voice-hearing, general emotional distress (depression, anxiety, stress) and wellbeing. The invariance of model parameters was examined across diagnosis and sex.

RESULTS

The final measurement model comprised two factors named 'voice severity' and 'voice-related distress'. The former comprised mainly physical voice characteristics and the latter mainly distress and other negative impacts. Structural model results supported voice-related distress as mediating the associations between voice severity and emotional distress and wellbeing. Model parameters were invariant across psychosis versus non-psychosis diagnosis and partially invariant across sex. Females experienced more severe and distressing voices and a more direct association between voice severity and general anxiety was evident.

CONCLUSIONS

The HPSVQ is a useful self-report measure of voice-hearing with some scope for further exploration and refinement. Voice-related distress appears a key mechanism by which voice severity predicts general distress and wellbeing. Whilst our data broadly support interventions targeting voice-related distress for all patients, females may benefit especially from interventions targeting voice severity and strategies for responding.

Facial Nerve EMG: Low-Tech Monitoring with a Stopwatch

OBJECTIVE

 The quantity of A-trains, a high-frequency pattern of free-running facial nerve electromyography, is correlated with the risk for postoperative high-grade facial nerve paresis. This correlation has been confirmed by automated analysis with dedicated algorithms and by visual offline analysis but not by audiovisual real-time analysis.

METHODS

 An investigator was presented with 29 complete data sets measured during actual surgeries in real time and without breaks in a random order. Data were presented either strictly via loudspeaker (audio) or simultaneously by loudspeaker and computer screen (audiovisual). Visible and/or audible A-train activity was then quantified by the investigator with the computerized equivalent of a stopwatch. The same data were also analyzed with quantification of A-trains by automated algorithms.

RESULTS

 Automated (auto) traintime (TT), known to be a small, yet highly representative fraction of overall A-train activity, ranged from 0.01 to 10.86 s (median: 0.58 s). In contrast, audio-TT ranged from 0 to 1,357.44 s (median: 29.69 s), and audiovisual-TT ranged from 0 to 786.57 s (median: 46.19 s). All three modalities were correlated to each other in a highly significant way. Likewise, all three modalities correlated significantly with the extent of postoperative facial paresis. As a rule of thumb, patients with visible/audible A-train activity < 1 minute presented with a more favorable clinical outcome than patients with > 1 minute of A-train activity.

CONCLUSION

 Detection and even quantification of A-trains is technically possible not only with intraoperative automated real-time calculation or postoperative visual offline analysis, but also with very basic monitoring equipment and real-time good quality audiovisual analysis. However, the investigator found audiovisual real-time-analysis to be very demanding; thus tools for automated quantification can be very helpful in this respect.

Electrospun Nimodipine-loaded fibers for nerve regeneration: Development and in vitro performance

Nimodipine is a 1,4-Dihydropyridine type calcium antagonist routinely used to control blood pressure and reduce the risk of secondary ischemia after aneurismal subarachnoid hemorrhage. Additionally, Nimodipine has unique neuroprotective properties. With respect to brain related applications, the full potential of the desired local effect can often not be realized after systemic administration due to systemic side effects. Therefore, it was our aim to develop a biodegradable drug delivery system for the local controlled release of the drug inside the brain. As a suitable and biodegradable system we successfully electrospun PLGA fibers containing 1 and 10% drug. The results of DSC and X-Ray diffractometry measurements indicate that Nimodipine was incorporated in the polymer matrix in the amorphous state. No drug recrystallization was detected for up to 6 months. Electron-beam sterilization was tried but reduced the drug content of the fiber mats considerably. A sustained drug release over 4-8 days was observed, highly depended on release conditions. The Nimodipine fiber mats exhibited no cell toxicity. In contrast, the electrospun fibers were able to significantly reduce cell death in in vitro cell models of oxidative, osmotic and heat-induced cell stress in Schwann cells, neuronal cells as well as immortalized and primary astrocytes. Therefore, electrospun Nimodipine loaded PLGA fibers represent a promising drug delivery system to realize the druǵs benefits for its intracranial use.

Neurophysiologisches Monitoring des Nervus facialis bei Operationen an Vestibularisschwannomen: Der aktuelle Stand

Hintergrund Nach Operationen an Vestibularisschwannomen gehören funktionelle Defizite des Nervus facialis zu den bedeutendsten Komplikationen. Mit Hilfe des intraoperativen neurophysiologischen Monitorings (IONM) sollen diese möglichst verhindert werden.

Fragestellung Welche Methoden zur Intraoperativen Funktionsüberwachung sind aktuell in Gebrauch, welche Ziele können damit sinnvoll verfolgt werden und welche Schwachpunkte bedürfen einer weiteren wissenschaftlichen Aufarbeitung?

Material und Methoden Auswertung und Zusammenfassung der Literatur, Diskussion der vorhandenen Methoden und ihrer Fähigkeiten, die gesteckten Ziele zu erreichen.

Ergebnisse Aus dem IONM abgeleitete Methoden des sogenannten „Mappings“ sollen den Nervus Facialis intraoperativ sicher identifizieren. IONM soll potenziell schädigende Ereignisse anzeigen und eine Einschätzung über den zu erwartenden postoperativen Funktionszustand des Nervs erlauben. Derzeit verwendet werden die elektrische Direktstimulation, das freilaufende EMG, Evozierte Potenziale des Nervus Facialis (MEP) und das prozessierte EMG. Vor allem in der Ergebnisprognostik haben alle vorhandenen Methoden deutliche Schwächen.

Schlussfolgerungen Das „Mapping“ der Nerven im OP-Situs kann mittels der elektrischen Direktstimulation gut realisiert werden. Nervenschädigungen während der Präparation können mit den anderen Methoden des IONM entweder in Echtzeit (freilaufendes EMG; prozessiertes EMG) oder nahezu in Echtzeit (MEP) angezeigt werden. Die Vorhersage des postoperativen, funktionellen Ergebnisses wird derzeit bei allen verfügbaren Methoden durch falsch positive Untersuchungsergebnisse mit konsekutiv niedrigem positiv prädiktivem Wert belastet.

[Preoperative determination of nerve of origin in patients with vestibular schwannoma. German version]

BACKGROUND

Vestibular schwannoma (VS) is a benign tumor that develops in the internal auditory canal and the cerebellopontine angle, potentially diminishing hearing or balance. Most VS tumors arise from one of two vestibular branches: the superior or inferior vestibular nerve. Determining the specific nerve of origin could improve patient management in terms of preoperative counseling, treatment selection, and surgical decision-making and planning. The aim of this study was to introduce a novel scoring system that was designed to determine the nerve of origin.

METHODS

The nerve of origin was predicted based on video head impulse assessments of all semicircular channels, together with cervical/ocular vestibular-evoked myogenic potential tests. The acquired data were entered into a scoring system developed to allocate the tumor origin. Finally, the nerve of origin was definitively determined intraoperatively.

RESULTS

The novel scoring system was applied to 5 consecutive patients undergoing surgical VS treatment. In one case, no determination was possible. In all other cases, the preoperatively predicted tumor origin was the same as the origin determined during surgery.

CONCLUSION

The scoring system predicts the nerve of origin and will be evaluated in a larger prospective cohort study of VS patients in the near future.

[Malignization of vestibular schwannoma 13 years after radiation therapy]

This article presents a case of malignant transformation of vestibular schwannoma 13 years after stereotactic radiation therapy, which lead to an acute life-threatening condition. Although the observation is currently only based on case reports, an increasing number of these support the hypothesis that there is a relevant risk of malignant transformation in the long-term course of previously irradiated vestibular schwannomas. Therefore, long-term MRI follow-up should be considered.

50 Shades of Red: The Predictive Value of Closed Suction Drains for the Detection of Postoperative Bleeding in Breast Surgery

BACKGROUND

While closed suction drains (CSDs) are still frequently employed in clinical practice, the supporting evidence is limited with some studies demonstrating a failure of routine CSD use in preventing hematoma or seroma. Nonetheless, CSD quantity and quality fluid assessment is still appreciated by clinicians to detect postoperative bleeding. This study investigates the value of routine CSD use, in breast surgery, to predict postoperative bleeding.

METHODS

A retrospective, intra-individual analysis, of CSD fluid volumes between the hematoma side and the unaffected contralateral breast, was undertaken in patients (n = 20) with unilateral postoperative bleeding following bilateral breast surgery (2003-2018). Statistical analysis was undertaken to establish a minimum cutoff fluid volume that might assist in the detection of postoperative bleeding. To determine the usefulness of quality assessment of CSD fluid output by visual inspection, surgeons (n = 56) prospectively matched six eligible hemoglobin concentrations corresponding to pre-filled CSDs.

RESULTS

Statistical analysis did not yield a clinically reliable cutoff fluid volume indicating postoperative bleeding. All six eligible hemoglobin concentrations were completely successfully matched to pre-filled CSDs by 30.4% (17/56) of surgeons.

CONCLUSIONS

This study questions the significance of routine CSD use to assist in the decision-making process to return to the theater and address postoperative bleeding. Quantity as well as quality analysis of CSD fluid output failed the reliability and diagnostic validity tests. Hemoglobin measurements in drain fluid specimens via blood gas analysis might contribute to the detection of postoperative bleeding.

LEVEL OF EVIDENCE IV

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

A critical comparison between the semisitting and the supine positioning in vestibular schwannoma surgery: subgroup analysis of a randomized, multicenter trial

OBJECTIVE

Patient positioning in vestibular schwannoma (VS) surgery is a matter of ongoing discussion. Factors to consider include preservation of cranial nerve functions, extent of tumor resection, and complications. The objective of this study was to determine the optimal patient positioning in VS surgery.

METHODS

A subgroup analysis of a randomized, multicenter trial that investigated the efficacy of prophylactic nimodipine in VS surgery was performed to investigate the impact of positioning (semisitting or supine) on extent of resection, functional outcomes, and complications. The data of 97 patients were collected prospectively. All procedures were performed via a retrosigmoid approach. The semisitting position was chosen in 56 patients, whereas 41 patients were treated while supine.

RESULTS

Complete resection was obtained at a higher percentage in the semisitting as compared to the supine position (93% vs 73%, p = 0.002). Logistic regression analysis revealed significantly better facial nerve function in the early postoperative course in the semisitting group (p = 0.004), particularly concerning severe facial nerve paresis (House-Brackmann grade IV or worse; p = 0.002). One year after surgery, facial nerve function recovered. However, there was still a tendency for better facial nerve function in the semisitting group (p = 0.091). There were no significant differences between groups regarding hearing preservation rates. Venous air embolism with the necessity to terminate surgery occurred in 2 patients in the semisitting position (3.6%). Supplementary analysis with a 2-tailed permutation randomization with 10,000 permutations of treatment choice and a propensity score matching showed either a tendency or significant results for better facial nerve outcomes in the early postoperative course and extent of resection in the semisitting group.

CONCLUSIONS

Although the results of the various statistical analyses are not uniform, the data indicate better results concerning both a higher rate of complete removal (according to the intraoperative impression of the surgeon) and facial nerve function after a semisitting as compared to the supine position. These advantages may justify the potential higher risk for severe complications of the semisitting position in VS surgery. The choice of positioning has to consider all individual patient parameters and risks carefully.

A-train clusters and the intermedius nerve in vestibular schwannoma patients

OBJECTIVE

EMG "A-train" activity correlates with postoperative facial palsy after vestibular schwannoma (VS) surgery. An intermedius nerve separate from the facial nerve increases A-trains without significant impact on function. We investigate occurrence of A-train "clusters", A-trains over a majority of channels within a short time frame.

METHODS

Data from 217 patients with first surgery for VS were evaluated retrospectively. Continuous EMG recorded with 9 channels was evaluated for A-train patterns. "Clusters" of A-trains were identified, i.e. A-trains within 3 seconds over a majority of channels. Relation to a separate intermedius, tumor size and facial palsy was evaluated.

RESULTS

Correlations between A-trains and postoperative facial palsy were higher in patients without separate intermedius (r = 0.562 versus r = 0.194). Clusters were identified in 107 patients (49.3%), separate intermedius in 109 (50.2%), with significant association of both (p < 0.001, Chi-Square test). Excluding clusters slightly increased correlation of A-trains to facial nerve function.

CONCLUSIONS

A-train clusters have limited relevance for predicting postoperative paresis. However, they should be regarded as warning signs, suggesting the presence of a separate intermedius nerve.

SIGNIFICANCE

A-train "clusters" are a sign of hyperactivity of the facial nerve due to a separate intermedius nerve and may confound intraoperative monitoring during VS surgery.

Case report: A fatal case of cryptococcosis in an immunocompetent patient due to Cryptococcus deuterogattii (AFLP6/VGII)

Introduction

Cryptococcosis in immunocompetent adults is a rare disease in Europe, mostly induced by members of the Cryptococcus gattii species complex. The diagnosis can be challenging due to its rarity, unspecific symptoms and long symptomless latency.

Case presentation

A 49-year-old woman with a three weeks history of headache was admitted to the hospital due to discrete ataxia and impaired vision. Cranial magnetic resonance imaging (MRI) showed a contrast-enhancing mass in the cerebellum. Further investigations detected a slight leukocytosis and a single subpleural nodule in the right inferior lung lobe. The cerebral lesion was surgically removed, and a direct frozen section only showed an unspecific inflammation. In the course of her admission she developed non-treatable cerebral edema and died ten days after surgical intervention. Histopathological examination of the surgical specimen and postmortem evaluation of the lung and the cerebrum demonstrated fungal elements. Molecular identification of the fungal elements in formalin-fixed paraffin-embedded tissue lead to the diagnosis of cryptococcosis induced by C. gattii sensu lato. Molecular genetic analysis identified the involved cryptococcal species as genotype AFLP6/VGII, recently described as Cryptococcus deuterogattii, which is known to be endemic to the west-coast of Canada and the USA. Additional heteroanamnestic information revealed that she had spent her holidays on Vancouver Island, Canada, two years before disease onset, indicating that infection during this stay seems to be plausible.

Conclusion

Cryptococcosis due to C. deuterogattii is a rarely encountered fungal disease in Europe, not particularly associated with immunodeficiency, and infection is likely to be contracted in endemic areas. Due to its rarity, long symptomless latency, unspecific symptoms and misleading radiological features the diagnosis can be challenging. Physicians need to be aware of this differential diagnosis in immunocompetent patients, as early adequate therapy can be lifesaving.

Reduced risk of venous thromboembolism with the use of intermittent pneumatic compression after craniotomy: a randomized controlled prospective study

OBJECTIVE

The term "venous thromboembolism" (VTE) subsumes deep venous thrombosis (DVT) and pulmonary embolism. The incidence of DVT after craniotomy was reported to be as high as 50%. Even clinically silent DVT may lead to potentially fatal pulmonary embolism. The risk of VTE is correlated with duration of surgery, and it appears likely that it develops during surgery. The present study aimed to evaluate intraoperative use of intermittent pneumatic compression (IPC) of the lower extremity for prevention of VTE in patients undergoing craniotomy.

METHODS

A total of 108 patients undergoing elective craniotomy for intracranial pathology were included in a single-center controlled randomized prospective study. In the control group, conventional compression stockings were worn during surgery. In the treatment group, IPC of the calves was used in addition. The presence of DVT was evaluated by Doppler sonography pre- and postoperatively.

RESULTS

Intraoperative use of IPC led to a significant reduction of VTE (p = 0.029). In logistic regression analysis, the risk of VTE was approximately quartered by the use of IPC. Duration of surgery was confirmed to be correlated with VTE incidence (p < 0.01); every hour of surgery increased the risk by a factor of 1.56.

CONCLUSIONS

Intraoperative use of IPC significantly lowers the incidence of potentially fatal VTE in patients undergoing craniotomy. The method is easy to use and carries no additional risks.■ CLASSIFICATION OF EVIDENCE Type of question: therapeutic; study design: randomized controlled trial; evidence: class I.Clinical trial registration no.: DRKS00011783 (https://www.drks.de).

[Intraoperative monitoring of cochlear nerve function during cerebello-pontine angle surgery]

BACKGROUND

Surgical procedures in the cerebello-pontine angle (CPA), e. g. for vestibular schwannoma, have an increased risk for damage to the cochlear nerve. Consequently, hearing deterioration up to complete deafness may result with severe impact on quality of life. Methods for intraoperative monitoring of function may minimize such risks.

OBJECTIVE

Review of current methods for intraoperative monitoring of the cochelar nerve and summary of new developments.

MATERIALS AND METHODS

Analysis and summary of literature, discussion of new methods.

RESULTS

Early auditory evoked potentials using click stimuli remain the standard method for intraoperative monitoring of cochlear nerve function. Amplitude and latency changes indicate a risk of postoperative hearing deterioration; however demonstrate only limited further differentiation of hearing quality. As novel methods, near-field recordings may allow faster feedback and auditory steady state responses potentially enable frequency specific testing.

CONCLUSIONS

Intraoperative monitoring of the cochlear nerve is an integral component of CPA surgery. It enables detection of potential nerve damage and thus contributes to avoiding postoperative functional deficits. Development and implementation of novel and additional approaches may further improve its clinical value.