ULTRASOUND IN VITRECTOMY: An Alternative Approach to Traditional Vitrectomy Techniques.

PURPOSE: To study a prototype of an ultrasound-based vitrector, and to try to understand the physical phenomena underlying this new technology. METHODS: We tested the ultrasound-based vitrector prototype (UV) (ultrasonically-driven handpiece obtained from a modified version of the Alcon CONSTELLATION Vision System [Alcon]) using an automatic experimental setup. Balanced saline solution (BSS) and vitreous (from fresh postmortem enucleated porcine eyes) flow rates were analyzed using three different tips. RESULTS: In general, BSS solution flow rates increased with increasing aspiration levels and decreased when we used % US power. Vitreous flow rates were influenced by aspiration levels, % US power, and ultrasound-related phenomena: cavitation phenomenon and "jet streaming." CONCLUSION: Ultrasound-based vitrectomy may represent an important alternative to traditional vitrectomy. Such a tool, capable of liquefying and excising the vitreous body using ultrasound, could overcome all the limits of the guillotine-based technique (GV). Knowledge of the physical phenomena underlying ultrasound-based technology is a necessary prerequisite for further development of this new technology.

Human oestriasis acquired in Florence and review on human myiasis in Italy.

Myiases-causing flies are widely observed in tropical countries, whereas in Italy, a temperate country, their epidemiology and clinical presentation are poorly known. We report three cases of human conjunctival myiasis recently observed at our hospital, and the results of a review of the literature on human myiasis in Italy. In August 2012, a case of Oestrus ovis conjunctival myiasis acquired in the city centre of Florence, Italy was diagnosed at our hospital. In the early fall of 2013, two additional cases, acquired in the neighbouring areas, occurred. The review of literature showed that, up to the middle of 1990s, myiasis in Italy was mainly an occupational disease of shepherds, caused by O. ovis. Recently, cases of travel acquired furuncular myiasis emerged, together with "opportunistic" autochthonous cases of wound myiasis in patients with underlying health conditions. Considering the causative agents of human of myiasis in Italy, among the 703 autochthonous cases reported, 98.1% were caused by O. ovis, while among the 42 imported cases described, 59.5% were due to Cordylobia spp. and 40.5% to Dermatobia hominis. Our findings suggest that O. ovis conjunctival myiasis may still be observed in urban setting in Italy. Health care providers should know and implement the basic rules of entomoprophylaxis for myiasis in the facilities where they are working and use these indications to educate patients and care givers in both pretravel care and geriatric outpatient settings.

Changes in pallidal neural activity following long-term symptom improvement from botulinum toxin treatment in DYT6 dystonia: a case report.

BACKGROUND: The globus pallidus internus is the main target for the treatment of dystonia by deep brain stimulation. Unfortunately, for some genetic etiologies, the therapeutic outcome of dystonia is less predictable. In particular, therapeutic outcomes for deep brain stimulation in craniocervical and orolaryngeal dystonia in DYT6-positive patients are poor. Little is known about the neurophysiology of the globus pallidus internus in DYT6-positive dystonia, and how symptomatic treatment affects the neural activity of this region. CASE PRESENTATION: We present here the case of a 55-year-old Caucasian female DYT6-dystonic patient with blepharospasm, spasmodic dysphonia, and oromandibular dystonia where single-unit and local field potential activity was recorded from the globus pallidus internus during two deep brain stimulation revision surgeries 4 years apart with no symptomatic improvement. Botulinum toxin injections consistently improved dysphonia, while some of the other symptoms were only inconsistently or marginally improved. Neural activity in the globus pallidus internus during both revision surgeries were compared with previously published results from an idiopathic dystonic cohort. Single-cell firing characteristics and local field potential from the first revision surgery showed no differences with our control group. However, during the second revision surgery, the mean firing rate of single units and local field potential power in the gamma range were lower than those present during the first revision surgery or the control group. CONCLUSIONS: Symptoms related to facial movements were greatly improved by botulinum toxin treatment between revision surgeries, which coincided with lower discharge rate and changes in gamma local field oscillations.

A randomised, double-blind, sham-controlled trial of deep brain stimulation of the bed nucleus of the stria terminalis for treatment-resistant obsessive-compulsive disorder.

Deep brain stimulation (DBS) is a promising treatment for severe, treatment-resistant obsessive-compulsive disorder (OCD). Here, nine participants (four females, mean age 47.9 ± 10.7 years) were implanted with DBS electrodes bilaterally in the bed nucleus of the stria terminalis (BNST). Following a one-month postoperative recovery phase, participants entered a three-month randomised, double-blind, sham-controlled phase before a twelve-month period of open-label stimulation incorporating a course of cognitive behavioural therapy (CBT). The primary outcome measure was OCD symptoms as rated with the Yale-Brown Obsessive-Compulsive Scale (YBOCS). In the blinded phase, there was a significant benefit of active stimulation over sham (p = 0.025, mean difference 4.9 points). After the open phase, the mean reduction in YBOCS was 16.6 ± 1.9 points (χ2 (11) = 39.8, p = 3.8 × 10-5), with seven participants classified as responders. CBT resulted in an additive YBOCS reduction of 4.8 ± 3.9 points (p = 0.011). There were two serious adverse events related to the DBS device, the most severe of which was an infection during the open phase necessitating device explantation. There were no serious psychiatric adverse events related to stimulation. An analysis of the structural connectivity of each participant's individualised stimulation field isolated right-hemispheric fibres associated with YBOCS reduction. These included subcortical tracts incorporating the amygdala, hippocampus and stria terminalis, in addition to cortical regions in the ventrolateral and ventromedial prefrontal cortex, parahippocampal, parietal and extrastriate visual cortex. In conclusion, this study provides further evidence supporting the efficacy and tolerability of DBS in the region of the BNST for individuals with otherwise treatment-refractory OCD and identifies a connectivity fingerprint associated with clinical benefit.

Evaluation of ocular perforation during retrobulbar block using high-resolution spectral domain-optical coherence tomography and optical coherence tomography angiography.

INTRODUCTION: This article reports a case of ocular perforation during a retrobulbar block in a patient who underwent scleral buckle for retinal detachment. METHODS: Sterile air was immediately injected into the vitreous cavity to restore intraocular pressure and the scleral buckle operation was quickly finished. One week later, a laser retinopexy was performed on the two retinal holes that were outside the foveal area. After 6 months, spectral domain-optical coherence tomography and optical coherence tomography angiography were performed on the perforated wall centered on the exit hole area. RESULTS: The visual acuity was maintained 20/20 and the retina was totally attached. Spectral domain-optical coherence tomography showed a localized interruption of inner retina, retinal pigment epithelium, and choroid, with a higher posterior reflectivity in correspondence with the sclera. Optical coherence tomography angiography was able to detect atrophic alterations in the choroidal slab with a good visualization of large and rarefied choroidal vessels due to lack of retinal pigment epithelium and choriocapillaris. CONCLUSION: When ocular perforation by a needle is outside the foveal area and when there is an early awareness of the perforation, the complications may be avoided, and we could observe a good final visual acuity result. Furthermore, using spectral domain-optical coherence tomography and optical coherence tomography angiography, we could observe the perforated eyeball wall and study the effects of a 25-gauge needle perforation in the retinal and choroidal blood stream.

Single-unit activity of the anterior Globus pallidus internus in Tourette patients and posterior Globus pallidus internus in dystonic patients.

OBJECTIVES: Our goal was to provide a detailed analysis of neurons' electrophysiological activity recorded in sub-territories of Globus pallidus internus (GPi) used as Deep Brain Stimulation (DBS) targets for these clinical conditions to potentially assist electrode targeting. METHODS: We used intra-operative microelectrode recording during stereotactic neurosurgery to guide implantation of DBS lead. RESULTS: Units in the medial anterior part of GPi of 7 Tourette's syndrome patients under general anesthesia were firing at mean and median rate of 32.1 and 21 Hz respectively (n = 101), with 45% of spikes fired during bursts and 21.3 bursts per minute. In the latero-posterior part of GPi of 7 dystonic patients under local anesthesia the mean and median activity were 46.1 and 30.6 Hz respectively (n = 27), and a mean of 21.7 bursts per minute was observed, with 30% of all spikes occurring during these bursts. CONCLUSION: Units activity pattern - slow-regular, fast-irregular or fast-regular were present in different proportions between the two targets. SIGNIFICANCE: The electrophysiological characteristics of the medial-anterior part of GPi and its latero-posterior portion can be used to assist DBS electrode targeting and also support the refinement of pathophysiological models of Tourette's syndrome and Dystonia.

Rotatable Small Permanent Magnet Array for Ultra-Low Field Nuclear Magnetic Resonance Instrumentation: A Concept Study.

OBJECT: We studied the feasibility of generating the variable magnetic fields required for ultra-low field nuclear magnetic resonance relaxometry with dynamically adjustable permanent magnets. Our motivation was to substitute traditional electromagnets by distributed permanent magnets, increasing system portability. MATERIALS AND METHODS: The finite element method (COMSOL®) was employed for the numerical study of a small permanent magnet array to calculate achievable magnetic field strength, homogeneity, switching time and magnetic forces. A manually operated prototype was simulated and constructed to validate the numerical approach and to verify the generated magnetic field. RESULTS: A concentric small permanent magnet array can be used to generate strong sample pre-polarisation and variable measurement fields for ultra-low field relaxometry via simple prescribed magnet rotations. Using the array, it is possible to achieve a pre-polarisation field strength above 100 mT and variable measurement fields ranging from 20-50 µT with 200 ppm absolute field homogeneity within a field-of-view of 5 x 5 x 5 cubic centimetres. CONCLUSIONS: A dynamic small permanent magnet array can generate multiple highly homogeneous magnetic fields required in ultra-low field nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) instruments. This design can significantly reduce the volume and energy requirements of traditional systems based on electromagnets, improving portability considerably.