Combined treatment of a medulla oblongata hemangioblastoma via permanent cysto-cisternal drainage and (postponed) gamma knife radiosurgery: a case report and review of the literature.

BACKGROUND: Hemangioblastomas are histologically benign tumors with a variable degree of morbidity and mortality based on various factors, including their anatomical location. The following paper illustrates a unique approach of combined therapy of a brainstem hemangioblastoma (HB) not associated with von Hippel-Lindau disease (vHLd) located in the medulla oblongata. CASE DESCRIPTION: A 21-year-old preschool teacher presented with vertigo, followed by dysphagia, trouble coughing, tongue paresis and headache and vomiting. Magnetic resonance imaging (MRI) revealed a large cystic lesion with a small intramural nodule located in the left anterolateral medulla oblongata directly behind the vertebral artery. The diagnosis of hemangioblastoma was supported by digital subtraction angiography. CONCLUSION: Combined therapy consisted primarily of acute surgical fenestration and permanent drainage of the cystic portion of the tumor, due to symptomatic expansion. Follow-up stereotactic gamma knife radiosurgery was performed after 2 years for minor progression of the tumor nodule. To the best of our knowledge, this is the first time such approach has been described in the literature for this pathology.

Anterior hippocampus volume loss in narcolepsy with cataplexy.

Narcolepsy with cataplexy is a lifelong disease resulting from the loss of hypocretin neurons in the hypothalamus; structural changes are not, however, limited only to the hypothalamus. We previously revealed an overall hippocampal volume loss in narcolepsy with cataplexy. The aim of this study is to describe the volume reduction of the anterior and posterior parts of the hippocampus in patients with narcolepsy with cataplexy in comparison with a control group. The anterior hippocampus is more involved in episodic memory and imagination, and the posterior hippocampus in spatial memory. Manual magnetic resonance imaging hippocampal volumetry was performed in 48 patients with narcolepsy with cataplexy and in 37 controls using the manual delineation technique in the ScanView program. All participants were examined on the same 1.5 T MR scanner; measurement was carried out as T1W 3D image with a slice thickness of 1.0/0 mm. There was a significant absolute loss of the total volume of the anterior hippocampus (sum of left and right) in patients with narcolepsy with cataplexy as compared with the controls (10.5%, p = .03 ANCOVA after correcting for total brain volume and multiple testing). We found a negative correlation between the total anterior hippocampus volume and the duration of the disease (R = -0.4036, p = .016-corrected for multiple testing).

Emotion stimulus processing in narcolepsy with cataplexy.

Reported brain abnormalities in anatomy and function in patients with narcolepsy with cataplexy led to a project based on qualitative electroencephalography examination and analysis in an attempt to find a narcolepsy with cataplexy-specific brain-derived pattern, or a sequence of brain locations involved in processing humorous stimuli. Laughter is the trigger of cataplexy in these patients, and the difference between patients and healthy controls during the laughter should therefore be notable. Twenty-six adult patients (14 male, 12 female) suffering from narcolepsy with cataplexy and 10 healthy controls (five male, five female) were examined. The experiment was performed using a 256-channel electroencephalogram and then processed using specialized software built according to the scientific research team's specifications. The software utilizes electroencephalographic data recorded during elevated emotional states in participants to calculate the sequence of brain areas involved in emotion processing using non-linear and linear algorithms. Results show significant differences in activation (pre-laughter) patterns between the patients with narcolepsy and healthy controls, as well as significant similarities within the patients and the controls. Specifically, gyrus orbitalis, rectus and occipitalis inferior are active in healthy controls, while gyrus paracentralis, cingularis and cuneus are activated solely in the patients in response to humorous audio stimulus. There are qualitative electroencephalographic-based patterns clearly discriminating between patients with narcolepsy and healthy controls during laughter processing.

Hippocampal but not amygdalar volume loss in narcolepsy with cataplexy.

OBJECTIVE: Narcolepsy with cataplexy (NC) and narcolepsy without cataplexy (NwoC) are lifelong neurological disorders characterized primarily by excessive daytime sleepiness. Emotional events such as laughter are a trigger of cataplexy in NC. METHODS: We compared the volumes of key limbic structures, the amygdala and hippocampus, in 53 NC, 23 NwoC and 37 control subjects. MRI volumetry was performed in FreeSurfer (FS) and by manual delineation. RESULTS: We found no differences in amygdalar volume in the three groups, however, hippocampal volume was significantly smaller in the NC group than in other groups. Amygdalar and hippocampal volumes assessed by FS were significantly greater, but strong positive correlation between manual and FS results were observed. Thus, both methods are suitable for amygdalar and hippocampal volumetry.

Anterior transposition of the radial nerve to achieve primary suture for its reconstruction: Anatomical feasibility study.

INTRODUCTION: Radial nerve palsy after humeral shaft fractures is often associated with formation of a neuroma in continuity. The current standard of treatment is neuroma resection and nerve grafting with contentious results. Anterior transposition of the radial nerve may reduce the length of its path, allowing reconstruction by primary suture. The aim of this study was to determine the maximum length of radial nerve defect that can be treated by the anterior transposition to allow primary suture to be performed. METHODS: We use 10 arms from five fresh cadavers. The radial nerve was dissected in the lateral inter-muscular septum and along the anterior aspect of the forearm. The radial nerve was transected at the level of the spiral groove and both stumps were than transposed anterior to the medial inter-muscular septum. The length of tension-free overlap that could be achieved was measured. RESULTS: The average length of the overlap at zero degrees of elbow flexion was 10.00 ± 1.84 mm. Theoretically, this will allow a defect of 20 ± 3.69 mm SD to be treated by primary suture. CONCLUSION: Our results suggest that anterior transposition can be used for radial nerve defects up to 2 cm; however, dissection of both stumps proved to be challenging.

Dogs are sensitive to small variations of the Earth's magnetic field.

INTRODUCTION: Several mammalian species spontaneously align their body axis with respect to the Earth's magnetic field (MF) lines in diverse behavioral contexts. Magnetic alignment is a suitable paradigm to scan for the occurrence of magnetosensitivity across animal taxa with the heuristic potential to contribute to the understanding of the mechanism of magnetoreception and identify further functions of magnetosensation apart from navigation. With this in mind we searched for signs of magnetic alignment in dogs. We measured the direction of the body axis in 70 dogs of 37 breeds during defecation (1,893 observations) and urination (5,582 observations) over a two-year period. After complete sampling, we sorted the data according to the geomagnetic conditions prevailing during the respective sampling periods. Relative declination and intensity changes of the MF during the respective dog walks were calculated from daily magnetograms. Directional preferences of dogs under different MF conditions were analyzed and tested by means of circular statistics. RESULTS: Dogs preferred to excrete with the body being aligned along the North-South axis under calm MF conditions. This directional behavior was abolished under unstable MF. The best predictor of the behavioral switch was the rate of change in declination, i.e., polar orientation of the MF. CONCLUSIONS: It is for the first time that (a) magnetic sensitivity was proved in dogs, (b) a measurable, predictable behavioral reaction upon natural MF fluctuations could be unambiguously proven in a mammal, and (c) high sensitivity to small changes in polarity, rather than in intensity, of MF was identified as biologically meaningful. Our findings open new horizons in magnetoreception research. Since the MF is calm in only about 20% of the daylight period, our findings might provide an explanation why many magnetoreception experiments were hardly replicable and why directional values of records in diverse observations are frequently compromised by scatter.

Anatomical feasibility study of the infraspinatus muscle neurotization by lower subscapular nerve.

OBJECTIVES: To investigate the anatomical feasibility of the infraspinatus branch of the suprascapular nerve (IB-SSN) reconstruction by lower subscapular nerve (LSN) transfer. METHODS: The morphological study was performed on 18 adult human cadavers. The length of the distal stump of the IB-SSN, the length of the LSN available for reconstruction and diameter of both stumps were measured. The feasibility study of the LSN to IB-SSN transfer was performed. RESULTS: The mean length of the IB-SSN to the end of its first branch was 40.9 mm (±4.6). Its mean diameter was 2.3 mm (±0.3). The mean length of the LSN stump, which was mobilized from its original course and transferred to reach the distal stump of the IB-SSN was 66.5 mm (±11.8). Its mean diameter was 2.1 mm (±0.3). The mean ratio between LSN and IB-SSN diameters was 0.9 (±0.1). The nerve transfer was feasible in 17 out of 18 cases (94.4%). CONCLUSION: This study demonstrates that direct LSN to IB-SSN transfer is anatomically feasible in most cases in the adult population. It may be used in cases of complex scapular fractures resulting in severe suprascapular nerve injury.

Volume of the amygdala is reduced in patients with narcolepsy - a structural MRI study.

OBJECTIVE: Based on the clinical observation that patients suffering from narcolepsy with cataplexy (NC) have cataplectic attacks when they experience positive emotions, it is therefore hypothesised that the abnormal processing of external emotional input through the limbic system, or motor dysregulation induced by emotions, takes place during these episodes. To date, imaging studies have failed to reveal consistent brain abnormalities in NC patients. METHODS: Considering the discrepancies in reported structural or functional abnormalities of the hypothalamus, amygdala, and nucleus accumbens, we used the MRI volumetry to determine the volumes of the amygdala and nucleus accumbens in a group of eleven patients with NC (5 males and 6 females, mean age 41.7 years ± 17.7). This data was compared to an equal number of examinations in healthy volunteers matched for age and gender. RESULTS: We found a decrease in the amygdalar volume of NC patients in both raw (p<0.001) and relative (p<0.01) data sets. The difference in amygdalar volume between healthy volunteers and NC patients was about 17%. In contrast to the amygdala, we did not find any differences in the volumes of nucleus accumbens. CONCLUSION: In the present MRI volumetric study, we found bilateral gray matter loss in the amygdala only.

Anatomical aspects of the selective infraspinatus muscle neurotization by spinal accessory nerve.

The suprascapular nerve (SSN) is commonly reconstructed by spinal accessory nerve (SAN) transfer. However, reinnervation of its branch to the infraspinatus muscle (IB-SSN) is poor. Reconstruction of the SSN in cases of scapular fractures is frequently neglected in clinical practice. The morphological study was performed on 25 adult human cadavers. The course and the length of SSN of minimal diameter of 2 mm within the trapezius muscle, the length of the distal stump of IB-SSN to its branching point and the length of the SSN available for reconstructive procedure were measured. The feasibility study of the SAN - IB-SSN neurotization performed by using a bony canal under the spine of scapula was performed. The mean distance of the SAN from the spine was 8.5 cm (±0.88) at the point where it perforates the trapezius muscle and 4.49 cm (±0.72) at the most distal part of the nerve. The mean length of the intramuscular portion of the nerve was 14.74 cm (±1.99). It ran under a mean latero-medial angle of 15.54° (±2.51). The mean distance between the medial end of the scapular spine and the SAN was 2.44 cm (± 0.64). The mean length of the IB-SSN was 3.6 cm (± 0.67). The mean length of the SAN stump which was mobilized from its original course and transferred to the infraspinous fossa to reach distal stump of the IB-SSN was 8.09 cm (±1.6). Direct SAN to IB-SSN transfer is anatomically feasible in the adult population.