Prädiktoren für das Auftreten eines Facettengelenkssyndroms nach lumbaler Bandscheibenoperation

Ein interventionsbedürftiges postoperatives Facettengelenkssyndrom (pFGS) ist ein weit verbreitetes Problem, welches auf eine lumbale Diskektomie (BSOP) folgen kann. Das Ziel dieser retrospektiven Studie war es mögliche Prädiktoren, chirurgische Aspekte oder individuelle charakteristische Merkmale zu identifizieren, die zur Entwicklung eines pFGS beitragen und die eine Verhinderung dieses häufigen postoperativen Problems ermöglichen können.509 Patienten, die sich zwischen 2006 und 2009 einer offenen mikrochirurgischen Diskektomie in unserer neurochirurgischen Klinik unterzogen haben und die in unserer Ambulanz zur Nachkontrolle erschienen sind, wurden in diese Studie eingeschlossen. Folgende Daten wurden aufgezeichnet: Geschlecht, Alter, prä- und postoperativer klinischer und neurologischer Status, Operationstechnik, Dauer der Operation, Auftreten eines Rezidivbandscheibenvorfalls, anschließende Rehabilitationsbehandlungen und Entwicklung eines pFGS. 43 Patienten (8,4%) entwickelten ein pFGS, was durch eine erfolgreiche Facettengelenkblockade bestätigt wurde. Patienten mit einem pFGS waren signifikant älter als diejenigen ohne pFGS (univariat 55,7 Jahre im Vergleich zu 50,9 Jahren; p=0,03) und hatten häufiger wiederkehrende Bandscheibenvorfälle (univariat p=0,001). Außerdem wurden die Dauer der Operation (p=0,01), intra- und postoperative Komplikationen (z.B. postoperative Blutungen, Duraverletzung, p=0,001) und Komorbidität (p=0,001) mit einem pFGS in assoziiert. Des Weiteren korrelierte die OP-Technik (Diskektomie versus Sequesterektomie, p=0,049) und die Durchführung einer postoperativen Rehabilitationsbehandlung (multivariat, p=0,019) mit einem pFGS. Die obengenannten Faktoren begünstigen statistisch signifikant das Auftreten eines relevanten pFGS. Unsere Ergebnisse charakterisieren ein Profil von Patienten, die ein erhöhtes Risiko für das Auftreten eines OP-assoziierten pFGS haben

Distance between Active Electrode Contacts and Dentatorubrothalamic Tract in Patients with Habituation of Stimulation Effect of Deep Brain Stimulation in Essential Tremor

Background Some patients under thalamic deep brain stimulation (DBS) for essential tremor (ET) experience habituation of tremor reduction. The nucleus ventralis intermedius (Vim) is the current main target side for ET in DBS. However, the dentatorubrothalamic tract (DRTT) is considered the relevant structure to stimulate. We investigated the distance between the active contact of the DBS electrode and the DRTT and compared this distance in patients with habituation of tremor reduction and good responders. Material and Methods In this retrospective study, we performed deterministic fiber tracking of the DRTT in 6 patients (12 hemispheres) with ET who underwent DBS in the Vim. We subsequently measured the distance between the active contact of the electrode and the ipsilateral DRTT in both hemispheres. The clinical tremor response of those 6 patients was analyzed accordingly. Results The distance between the active contact and the DRTT in patients with better and constant clinical tremor reduction was shorter (mean distance: 2.9 +/- 2.2 mm standard deviation [SD]) than in patients who showed habituation of their response (mean distance: 6.1 +/- 3.9 mm SD). After re-placement of a thalamic electrode inside the DRTT in one patient who experienced unsatisfying tremor reduction due to habituation of stimulation, the tremor alleviation was significant and persistent at a 13-month follow-up. Conclusion This retrospective analysis suggests that recurrence of ET tremor under chronic DBS might be associated with a larger distance between the DRTT and the active lead contact, in comparison with the smaller distances in patients with persistently good tremor control

Expression of fatty acid synthase in nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is characterized by hepatic lipid accumulation which starts with simple hepatic steatosis and may progress toward inflammation (nonalcoholic steatohepatitis [NASH]). Fatty acid synthase (FASN) catalyzes the last step in fatty acid biosynthesis, and thus, it is believed to be a major determinant of the maximal hepatic capacity to generate fatty acids by de novo lipogenesis. The aim of this study was to analyze the correlation between hepatic steatosis and inflammation with FASN expression. In vitro incubation of primary human hepatocytes with fatty acids dose-dependently induced cellular lipid-accumulation and FASN expression, while stimulation with TNF did not affect FASN levels. Further, hepatic FASN expression was significantly increased in vivo in a murine model of hepatic steatosis without significant inflammation but not in a murine NASH model as compared to control mice. Also, FASN expression was not increased in mice subjected to bile duct ligation, an experimental model characterized by severe hepatocellular damage and inflammation. Furthermore, FASN expression was analyzed in 102 human control or NAFLD livers applying tissue micro array technology and immunohistochemistry, and correlated significantly with the degree of hepatic steatosis, but not with inflammation or ballooning of hepatocytes. Quantification of FASN mRNA expression in human liver samples confirmed significantly higher FASN levels in hepatic steatosis but not in NASH, and expression of SREBP1, which is the main transcriptional regulator of FASN, paralleled FASN expression levels in human and experimental NAFLD. In conclusion, the transcriptional induction of FASN expression in hepatic steatosis is impaired in NASH, while hepatic inflammation in the absence of steatosis does not affect FASN expression, suggesting that FASN may serve as a new diagnostic marker or therapeutic target for the progression of NAFLD

Probabilistic vs. deterministic fiber tracking and the influence of different seed regions to delineate cerebellar-thalamic fibers in deep brain stimulation

This study compared tractography approaches for identifying cerebellar-thalamic fiber bundles relevant to planning target sites for deep brain stimulation (DBS). In particular, probabilistic and deterministic tracking of the dentate-rubro-thalamic tract (DRTT) and differences between the spatial courses of the DRTT and the cerebello-thalamo-cortical (CTC) tract were compared. Six patients with movement disorders were examined by magnetic resonance imaging (MRI), including two sets of diffusion-weighted images (12 and 64 directions). Probabilistic and deterministic tractography was applied on each diffusion-weighted dataset to delineate the DRTT. Results were compared with regard to their sensitivity in revealing the DRTT and additional fiber tracts and processing time. Two sets of regions-of-interests (ROIs) guided deterministic tractography of the DRTT or the CTC, respectively. Tract distances to an atlas-based reference target were compared. Probabilistic fiber tracking with 64 orientations detected the DRTT in all twelve hemispheres. Deterministic tracking detected the DRTT in nine (12 directions) and in only two (64 directions) hemispheres. Probabilistic tracking was more sensitive in detecting additional fibers (e.g. ansa lenticularis and medial forebrain bundle) than deterministic tracking. Probabilistic tracking lasted substantially longer than deterministic. Deterministic tracking was more sensitive in detecting the CTC than the DRTT. CTC tracts were located adjacent but consistently more posterior to DRTT tracts. These results suggest that probabilistic tracking is more sensitive and robust in detecting the DRTT but harder to implement than deterministic approaches. Although sensitivity of deterministic tracking is higher for the CTC than the DRTT, targets for DBS based on these tracts likely differ