Retroclival Arachnoid Cysts: Case Series, Literature Review, and New Classification Proposal.

BACKGROUND: The retroclival region is among the rarest locations for an arachnoid cyst (AC), with only a few reported cases. No accepted classification system is available for these rare cysts. Such a classification system would solve the nomenclature problem and could result in easier and more systematic management. We reviewed and analyzed data from databases and reported studies of retroclival ACs (RACs) and have proposed a classification system. METHODS: A retrospective review of RACs was conducted in Marmara and Adiyaman University Hospitals, Turkey. Cysts in the prepontine and/or premedullary cisterns that spared the chiasmatic cistern were included. Additionally, the reported data were searched for relevant studies on cysts. The findings were analyzed to establish a clear nomenclature and classification system, and the clinical presentations, treatment strategies, and surgical approaches were reviewed. RESULTS: We identified 1 adult and 1 pediatric patient, and only the adult had undergone surgery. Additional data searches yielded 14 patients with RACs. The cysts were classified as type 1 if they had extended superiorly beyond the borders of the diencephalic leaf of the Liliequist membrane. If they had not extended, they were classified as type 2. Finally, type 2 cysts that had extended to the anterior spinal cistern were classified as type 3. CONCLUSIONS: RACs can be more easily and systematically managed using a simple clinical classification system. Together with the previously proposed suprasellar AC classification, our proposed RAC classification should be adequate to classify all ACs in the ventral midline cistern, which could solve the nomenclature problem.

Prelimbic Cortex Deep Brain Stimulation Reduces Binge Size in a Chronic Binge Eating Rat Model.

BACKGROUND: Binge eating (BE) involves the consumption of a large amount of food in a short period of time and a loss of control during the binge episode. It is a key feature of the major subtypes of eating disorders like bulimia nervosa, BE disorder, anorexia nervosa binge/purge type. Alterations in the mesocorticolimbic pathway play a crucial role in its pathophysiology. OBJECTIVES: We hypothesized that BE rats receiving deep brain stimulation (DBS) in the prelimbic cortex, a functional analog of the dorsolateral prefrontal cortex in humans, would have a reduced binge size compared with those receiving sham stimulation. METHODS: Eight male Sprague-Dawley rats were implanted with a DBS electrode in the left prelimbic cortex. A protocol which included limited access to a "sweet-fat" diet was used to achieve a chronic BE state in the rats. After reaching a stable binge size, each rat had undergone sham, low-frequency stimulation (60 Hz), and high-frequency (130 Hz) stimulation for 3 sessions each, and 2 consecutive treatments were separated by at least 2 empty sessions to allow a washout of the effects. A one-way ANOVA was used for the data analysis. RESULTS: Low-frequency (60 Hz) stimulation of the prelimbic cortex significantly reduced the binge size compared to the sham stimulation (p < 0.0001). High-frequency DBS (130 Hz) had no significant influence on this behavior when compared to sham stimulation (p = 0.9). CONCLUSIONS: This study suggests that low-frequency prelimbic cortex stimulation in BE would be useful for correcting prefrontal hypofunction which is strongly associated with BE and addiction pathogenesis.

Antimicrobial Effect of Polymer-Based Silver Nanoparticle Coated Pedicle Screws: Experimental Research on Biofilm Inhibition in Rabbits.

STUDY DESIGN: Antimicrobial effect of a novel silver-impregnated pedicle screw in rabbits. OBJECTIVE: A novel spine implant model was designed to study the antimicrobial effect of a modified Titanium (Ti) pedicle screws with methicillin-resistant Staphylococcus aureus (MRSA) in multiple surgical sites in the lumbar spine of a rabbit. SUMMARY OF BACKGROUND DATA: Infection in spinal implant is of great concern. Anti-infection strategies must be tested in relevant animal models that will lead to appropriate clinical studies. METHODS: Fourteen New Zealand white rabbits were divided into 2 groups: group 1: infected unmodified Ti screw group (n =  6), and group 2: infected polyethylene glycol grafted, polypropylene-based silver nanoparticle (PP-g-PEG-Ag) covered Ti screw group (n = 6), and 2 rabbits as sterile (sham-operated and control) group. In all groups, left L4-right L6 vertebra levels were exposed and screws were drilled to transverse processes after contamination of burr holes and surrounding tissue with 0.1 mL of 10 colony forming units (CFU) MRSA solutions in groups 1 and 2. After 21 days, samples were collected and infection was analyzed via light and scanning electron microscopy and culturing. Silver nanoparticles (Ag-NP) on the screws and tissues were assayed pre and postoperatively. RESULTS: The bacterial colony count for modified-Ti screw group was lower than for unmodified Ti screw (17.2 versus 200 x 10(3) CFU/mL, P = 0.029) with less biofilm formation. There was no difference in duration of surgery among groups and within the surgical sites. Ag-NPs were detected on the screw surface postoperatively. CONCLUSION: This novel experimental design of implantation in rabbits is easy to apply and resembles human stabilization technique. Modified Ti screws were shown to have antimicrobial effect especially inhibiting the biofilm formation. This anchored Ag NPs that remained after 21st day of implantation shows that it is resistant to tapping forces of the screw.

A sine-wave-shaped skin incision for inserting deep-brain stimulators.

BACKGROUND: The sine-wave-shaped skin incision is a technique that minimizes skin-related complications near burr hole caps after electrode placement for deep-brain stimulation (DBS). METHODS: Between 2011 and 2013, 54 DBS electrodes were implanted in 27 consecutive patients with Parkinson's disease (PD), essential tremor, or dystonia. The sine-wave incision was used in 26 patients and conventional bilateral linear scalp incisions were used in one patient. RESULTS: None of the patients whose operations involved sine-wave-shaped incisions developed hardware-linked complications such as skin infection or skin erosion. The one patient who underwent conventional bilateral linear scalp incisions developed a skin infection. CONCLUSION: By preserving the vascular anatomy of the scalp and reducing skin tension at the wound site, the sine-wave-shaped incision promotes wound healing.

Spontaneous remission of acromegaly after infarctive apoplexy with a possible relation to MRI and diabetes mellitus.

OBJECTIVES: Pituitary apoplexy is a rare clinical syndrome associated with rapid enlargement of a pituitary mass. We report the initial presentation, subsequent course and outcome of an acromegalic patient who developed spontaneous remission following pituitary apoplexy with pathologic findings of tumor infarction. CLINICAL PRESENTATION: A 38 year-old man with typical acromegalic features was referred to our hospital. He had been diabetic and hypertensive. His basal GH and IGF-1 levels were high (80 µg/L and 747 ng/mL respectively). Sella MRI showed a macroadenoma about 19×20 mm in size. He admitted to emergency department with complains of severe frontal headache accompanied by nausea and vomiting two days after MRI was taken. His neurological examination and visual field test were normal. Emergent MRI of the sella disclosed an enhancing intrasellar mass of 24×23 mm compressing the optic chiasm. The patient underwent transsphenoidal decompression of the lesion. Histological examination revealed an adenomatous tissue showing nonhemorrhagic coagulation necrosis. Before surgery, his GH levels declined to 2.72 µg/L spontaneously and after surgery he was in remission even leading to a state of growth hormone deficiency. CONCLUSION: When apoplexy occurs in functioning adenomas, it may cause spontaneous remission. However pituitary apoplexy due to tumor infarction is very rare. Various precipitating factors have been reported in 25-30% of pituitary apoplexy patients. Diabetes mellitus and diabetic ketoacidosis are one of these. The presence of contrast media induced endothelial swelling with the result of hypoperfusion and diabetes mellitus associated vasculopathy might be a precipitating factor in this patient.

Comparison of intrathecal cilostazol and nimodipine treatments in subarachnoid hemorrhage: an experimental study in rabbits.

OBJECTIVE: intrathecal administration of calcium channel antagonists has been proposed to reduce cerebral vasospasm (CVS) in animal subarachnoid hemorrhage (SAH) models. Also, delayed CVS treatment model with oral administration of cilostazol can be seen in the literature. METHODS: in this study, 25 male New Zealand white rabbits were randomly assigned to five groups: control, SAH only, SAH/nimodipine, SAH/cilostazol, SAH/vehicle. The animals' basilar arteries were sectioned from four separate zones and four sections were obtained from each rabbit. Basilar artery luminal section areas were measured by using SPOT for windows Version 4.1 computer program. RESULTS: basilar artery luminal section areas in SAH/ nimodipine and SAH/ cilostazol groups were significantly higher than SAH only group (P < 0.05). CONCLUSION: phosphodiesterase 3 inhibitor cilostazol has vasodilatory effects without affecting cerebral blood flow. Nimodipine is a calcium channel blocker and is still used in vasospasm therapy either oral or intravenously. This study demonstrates that prophylactic bolus intrathecal administration of either cilostazol or nimodipine equally prevents SAH-associated CVS in an animal model. We therefore propose that cilostazol is a candidate for clinical trials in the treatment of delayed vasospasm.