Do statins reduce the rate of revision surgery after chronic subdural hematoma drain?

BACKGROUND: With chronic subdural hematoma (CSDH), surgery is the therapeutic mainstay for large or symptomatic cases. Statins are reported to be effective as the primary therapy of CSDH to obviate the need for surgery. However, the effect of statins on the postoperative course of CSDH is largely unclear. We therefore sought to determine whether statins reduce the rate of repeat surgery after CSDH drain. METHODS: We performed an analysis of all patients who underwent surgery for CSDH at our institution between 2012 and 2018. The patients were separated into those who received statins as part of their previous medication (statin group) and those who did not (control group). The medical records were reviewed for repeat surgeries and complications. Additionally, patients or their relatives were contacted via phone to obtain missing data and inquire about possible repeat surgeries at other institutions. RESULTS: We identified 407 patients who received CSDH evacuation via burr hole craniotomy. In total, 123 patients were treated with statins as part of their daily medication. Repeat surgery was performed in 26 patients in the statin group (21.1%) and 57 patients in the non-statin group (20.1%, p = 0.81). Upon multivariate logistic regression analysis, neither of the variables statins, age, antithrombotic medication, Charlson comorbidity index, or Markwalder grading score yielded a statistically significant effect upon the revision rate. CONCLUSIONS: We found no evidence for the protective effect of statins in patients who underwent surgery for CSDH. We thus conclude that statin therapy is not warranted for CSDH perioperatively.

Ischaemic post-conditioning in rats: Responder and non-responder differ in transcriptome of mitochondrial proteins.

Ischaemic post-conditioning (IPoC) is a clinical applicable procedure to reduce reperfusion injury. Non-responsiveness to IPoC possibly caused by co-morbidities limits its clinical attractiveness. We analysed differences in the expression of mitochondrial proteins between IPoC responder (IPoC-R) and non-responder (IPoC-NR). Eighty rats were randomly grouped to sham, ischaemia/reperfusion (I/R), IPoC or ischaemic pre-conditioning (IPC, as positive cardioprotective intervention) in vivo. Infarct sizes were quantified by plasma troponin I levels 60 minutes after reperfusion. After 7 days, rats were sacrificed and left ventricular tissue was taken for post hoc analysis. The transcriptome was analysed by qRT-PCR and small RNA sequencing. Key findings were verified by immunoblots. I/R increased plasma troponin I levels compared to Sham. IPC reduced troponin I compared to I/R, whereas IPoC produced either excellent protection (IPoC-R) or no protection (IPoC-NR). Twenty-one miRs were up-regulated by I/R and modified by IPoC. qRT-PCR analysis revealed that IPoC-R differed from other groups by reduced expression of arginase-2 and bax, whereas the mitochondrial uncoupling protein (UCP)-2 was induced in IPC and IPoC-R. IPoC-R and IPoC-NR synergistically increased the expression of non-mitochondrial proteins like VEGF and SERCA2a independent of the infarct size. Cardiac function was more closely linked to differences in mitochondrial proteins than on regulation of calcium-handling proteins. In conclusion, healthy rats could not always be protected by IPoC. IPoC-NR displayed an incomplete responsiveness which is reflected by different changes in the mitochondrial transcriptome compared to IPoC-R. This study underlines the importance of mitochondrial proteins for successful long-term outcome.

Clinical Validation of Quality Improvements Using the Six Sigma Concept: A Case Study for Deep Brain Stimulation in Parkinson's Disease.

BACKGROUND: The Six Sigma concept allows for the evaluation of quality changes after the implementation of new technical equipment or adjustment of perioperative procedures. Exemplarily, we applied this method for quality assessment in deep brain stimulation surgery (DBS) for Parkinson's disease. METHODS: The medical procedure and possible errors were registered. Then, 6 critical-to-quality characteristics regarding clinical outcome, surgical precision, and the surgical process were measured. The surgical procedure was then optimized in 2 steps, and its measurement, along with the analysis, was repeated twice. RESULTS: By optimizing perioperative settings, the operation time could be reduced, and the precision of the lead placement could be increased. Clinical outcome, as measured by improvement in UPDRS-III, IV, and reduction of medication could also be improved with smaller required stimulation voltage. With directional leads considerable reduction of medication was achieved in 97% of patients (σ-value 3.39) compared to 83.7% (σ-value 2.53) with nondirectional leads. CONCLUSION: This study shows that the Six Sigma concept is a suitable quality tool to analyze and improve treatment quality of complex medical procedures such as lead positioning in DBS surgery in clinical routine. Our results suggest that directional leads in subthalamic nucleus DBS may have a favorable impact on patients' outcome.

Somatosensory functional MRI tractography for individualized targeting of deep brain stimulation in patients with chronic pain after brachial plexus injury.

BACKGROUND: The optimal targets for deep brain stimulation (DBS) in patients with refractory chronic pain are not clearly defined. We applied sensory functional MRI (fMRI)- and diffusion tensor imaging (DTI)-based DBS in chronic pain patients into 3 different targets to ascertain the most beneficial individual stimulation site. METHODS: Three patients with incapacitating chronic pain underwent DBS into 3 targets (periventricular gray (PVG), ventroposterolateral thalamus (VPL), and posterior limb of the internal capsule according to fMRI and DTI (PLIC). The electrodes were externalized and double-blinded tested for several days. Finally, the two electrodes with the best pain reduction were kept for permanent stimulation. The patients were then followed up for 12 months. Outcome measures comprised the numerical rating scale (NRS), short-form McGill's score (SF-MPQ), and health-related quality of life (SF-36). RESULTS: Continuous pain (mean NRS 6.6) was reduced to NRS 3.6 after 12 months. Only with stimulation of the PLIC pain attacks, that occurred at least 3 times a week (mean NRS 9.6) resolved in 2 patients and improved in one patient concerning both intensity (NRS 5) and frequency (twice a month). The mean SF-MPQ decreased from 92.7 to 50. The health-related quality of life improved considerably. CONCLUSION: fMRI- and DTI-based DBS to the PLIC was the only target with a significant effect on pain attacks and seems to be the most promising target in chronic pain patients after brachial plexus injury. The combination with PVG or VPL can further improve patients' outcome especially in terms of reducing the continuous pain.

Safety and Effectiveness of Bis-Chloroethylnitrosourea Wafer Chemotherapy in Elderly Patients with Recurrent Glioblastoma.

OBJECTIVE: To assess the safety and effectiveness of bis-chloroethylnitrosourea (BCNU) wafers in elderly patients with recurrent glioblastoma (GBM). METHODS: Patients with recurrent GBM operated on between 2007 and 2014 were divided into 3 groups: >65 years with BCNU wafer implantation, >65 years without BCNU wafer implantation, and ≤65 years with BCNU wafer implantation. We compared survival and complications. RESULTS: A total of 79 patients were identified: 24 in the older BCNU group (median age 68.2 years, 33.3% with a methylated MGMT promoter), 16 in the older non-BCNU group (median age 68.6 years, 31.3% with a methylated MGMT promoter), and 39 in the younger BCNU group (median age 56.8 years). Survival after progression was 9.2 months in the elderly BCNU group and 7.6 months in the elderly non-BCNU group (p = 0.34); overall survival was 17.2 and 15.9 months, respectively (p = 0.35). We found a tendency toward a higher rate of seizures and pneumonia in the older BCNU group. CONCLUSION: BCNU wafer implantation after resection of recurrent GBM is a reasonably safe treatment in patients aged >65 years. Seizures and systemic infections may occur more frequently, but the trade-off is still favorable as survival may be influenced positively. Higher age should not be regarded as a contraindication for BCNU wafers.

Bilateral thalamic deep brain stimulation for essential tremor in elderly patients.

The purpose of this study was to assess the influence of age on thalamic deep brain stimulation (DBS) in essential tremor (ET). Tremor, cognition, mood and adverse events in patients with thalamic DBS for ET were evaluated in 26 consecutive patients with established standardized methods for tremor and cognition. Twelve patients <70 and 14 patients ≥70 years were included and followed for 2 years. Clinical outcomes did not differ significantly. DBS seems to be safe and effective for ET independent of age.

Peripheral nerve field stimulation for trigeminal neuralgia, trigeminal neuropathic pain, and persistent idiopathic facial pain.

OBJECTIVE: Peripheral nerve field stimulation (PNFS) is a promising modality for treatment of intractable facial pain. However, evidence is sparse. We are therefore presenting our experience with this technique in a small patient cohort. METHODS: Records of 10 patients (five men, five women) with intractable facial pain who underwent implantation of one or several subcutaneous electrodes for trigeminal nerve field stimulation were retrospectively analyzed. Patients' data, including pain location, etiology, duration, previous treatments, long-term effects and complications, were evaluated. RESULTS: Four patients suffered from recurrent classical trigeminal neuralgia, one had classical trigeminal neuralgia and was medically unfit for microvascular decompression. Two patients suffered from trigeminal neuropathy attributed to multiple sclerosis, one from post-herpetic neuropathy, one from trigeminal neuropathy following radiation therapy and one from persistent idiopathic facial pain. Average patient age was 74.2 years (range 57-87), and average symptom duration was 10.6 years (range 2-17). Eight patients proceeded to implantation after successful trial. Average follow-up after implantation was 11.3 months (range 5-28). Using the visual analog scale, average pain intensity was 9.3 (range 7-10) preoperatively and 0.75 (range 0-3) postoperatively. Six patients reported absence of pain with stimulation; two had only slight constant pain without attacks. CONCLUSION: PNFS may be an effective treatment for refractory facial pain and yields high patient satisfaction.

Peripheral nerve field stimulation in medically refractory trigeminal neuralgia attributed to multiple sclerosis.

OBJECTIVE: Case reports and small patient series have suggested peripheral nerve field stimulation (PNFS) as a treatment for refractory trigeminal neuralgia attributed to multiple sclerosis (MS). Here, the authors aimed to assess the effects of this technique on long-term pain severity. METHODS: Data were prospectively collected on patients with refractory trigeminal neuralgia attributed to MS who underwent PNFS between July 2013 and August 2017 at the authors' neurosurgical department. Patients were evaluated before and after the first treatment as well as at follow-up at least twice a year. Patients underwent assessment of their pain severity using the Barrow Neurological Institute (BNI) Scale before treatment and at follow-up and were questioned about adverse events following cranial MRI performed after implantation of a permanent PNFS system. RESULTS: Eight patients (3 women) underwent PNFS trials and their median age was 61 years (IQR 73.75 - 46.5 years). Seven patients proceeded to permanent implantation of the stimulation system. At a median follow-up of 33 months (IQR 42 - 24 months), pain severity decreased from baseline to the last follow-up (BNI score decrease from V [IQR V - V] to III [IQR V - III], p = 0.054). Four patients experienced long-lasting benefit (at 48, 33, 24, and 15 months' follow-up, respectively), while in 3 patients the treatment eventually failed after an initially successful period. One patient had an infection, requiring system removal and subsequent reimplantation. No other complications occurred. No adverse events were noted in the patients undergoing MRI postimplantation. CONCLUSIONS: This analysis indicates a possibly beneficial long-term effect of PNFS on refractory trigeminal neuralgia attributed to MS in some patients.

A Systematic Review of the Semi-Sitting Position in Neurosurgical Patients with Patent Foramen Ovale: How Frequent Is Paradoxical Embolism?

BACKGROUND: The semi-sitting position is preferred in some surgeries of the posterior fossa and the cervical spine. At the same time, it is associated with a risk of air embolism. In the presence of a patent foramen ovale (PFO) with an intracardial right-to-left shunt, an air embolism can result in a paradoxical embolism to the heart or brain. It is unclear whether the risk-benefit ratio favors the semi-sitting position in this scenario. METHODS: We conducted a systematic review of the relevant studies published after 2007 by searching the PubMed, Science Direct, and Cochrane Database of Systematic Reviews databases. Studies in which the presence of PFO was stated and the occurrence of paradoxical embolism was evaluated in patients who underwent neurosurgical procedures in the semi-sitting position were included in our analysis. RESULTS: We identified 4 observational studies with a total of 977 patients who underwent surgery of the posterior fossa or cervical spine in the semi-sitting position; among these, 82 had a PFO. Air embolism occurred in 33 of these 82 patients (40.2%). No paradoxical embolisms were detected. CONCLUSIONS: In experienced medical centers, neurosurgery in the semi-sitting position is feasible with acceptable risk even in patients with PFO. If the PFO is large, or if a permanent right-to-left shunt is present in a patient with a history of paradoxical embolism, it may be reasonable to repair the PFO before surgery if the semi-sitting position is strongly preferred. The risk analysis must be done on a case-by-case basis.

Catalytic Systems for the Cross-Linking of Organosilicon Polymers.

Silicones and silicone rubbers are omnipresent in household and industrial products such as lubricants, coatings, sealants, insulators, medical devices, etc. This plethora of applications arises from their unparalleled properties including hydrophobicity, low surface energy, chemical inertness, extreme temperature stability, elasticity, and biocompatibility. Even though silicones have been known for more than five decades, their chemistry is still far from fully understood. Industrially, the vast majority of processes for their synthesis, transformation, and use are based on rather well established, alas outdated technologies, which are frequently empirical and poorly investigated. This review attempts to summarize the different approaches for the synthesis of silicone rubbers by vulcanization or curing of silicone polymers, the catalysts used, and the corresponding reaction mechanisms. Apart from the well-known methods (radical, hydrosilylation, and metal-based condensation), novel approaches such as organo- and bio-catalysis are also addressed.

Recent Developments in the Preparation of Silicones with Antimicrobial Properties.

This Focus Review describes state-of-the-art methods for the preparation of antimicrobial silicones. Given the diversity of antimicrobial activity and their mechanisms, the performance of these materials is highly dependent on the characteristics of the polymeric matrix. Therefore, different synthetic routes have been developed, such as 1) physical treatments, 2) chemical transformations, and 3) copolymerization. This classification is not exclusive, so some products belong to more than one class. Herein, we attempt to present a handy overview of the development of antimicrobial silicones, their most important application fields, the most relevant antimicrobial assays, and, as the title suggests, an overview of the most relevant preparation methods.

The Effect of Cataract on Early Stage Glaucoma Detection Using Spatial and Temporal Contrast Sensitivity Tests.

BACKGROUND: To investigate the effect of cataract on the ability of spatial and temporal contrast sensitivity tests used to detect early glaucoma. METHODS: Twenty-seven glaucoma subjects with early cataract (mean age 60 ± 10.2 years) which constituted the test group were recruited together with twenty-seven controls (cataract only) matched for age and cataract type from a primary eye care setting. Contrast sensitivity to flickering gratings at 20 Hz and stationary gratings with and without glare, were measured for 0.5, 1.5 and 3 cycles per degree (cpd) in central vision. Perimetry and structural measurements with the Heidelberg Retinal Tomograph (HRT) were also performed. RESULTS: After considering the effect of cataract, contrast sensitivity to stationary gratings was reduced in the test group compared with controls with a statistically significant mean difference of 0.2 log units independent of spatial frequency. The flicker test showed a significant difference between test and control group at 1.5 and 3 cpd (p = 0.019 and p = 0.011 respectively). The percentage of glaucoma patients who could not see the temporal modulation was much higher compared with their cataract only counterparts. A significant correlation was found between the reduction of contrast sensitivity caused by glare and the Glaucoma Probability Score (GPS) as measured with the HRT (p<0.005). CONCLUSIONS: These findings indicate that both spatial and temporal contrast sensitivity tests are suitable for distinguishing between vision loss as a consequence of glaucoma and vision loss caused by cataract only. The correlation between glare factor and GPS suggests that there may be an increase in intraocular stray light in glaucoma.