Thermal finite element analysis of localized hypothermia treatment of the human eye.

Localized hypothermia treatment can reduce the risk of vision loss due to ocular trauma. Hypothermia reduces inflammation and metabolic rate, and improves blood flow to prevent nerve and tissue damage. This paper presents a finite element thermal analysis to determine the efficacy of local hypothermia treatment administered using a scleral eye contact ring that acts as a heat sink. A realistic model of the human eye orbit, including fat and muscle, is created using MRI scans. A simplified CAD-based model is also created based on the first model. A transient analysis is performed by lowering the contact surface between the device and the eye to 4∘C. The study shows that the device lowers the temperature of the optic nerve head to a therapeutic range of 32-34∘C in less than 10 min of treatment, hence supporting the efficacy of such a device.

THERMAL ANALYSIS OF INTRAOCULAR ELECTRONIC DISPLAY PROJECTOR VISUAL PROSTHESIS.

Corneal opacity is a leading cause of blindness, accounting for about 4% of global blindness. With corneal opacity, light is unable to pass through the cornea to form a clear image on the retina, resulting in blindness. To address this condition, an intraocular projection device has been designed. This device, while in use, would produce heat. According to international standard regulations, the temperature on the surface of the tissues should not increase more than 2°C due to medical devices. In order to establish the power budget of this intraocular electronic device, a steady state thermal finite element analysis was conducted on two different eye models. The device was placed at 9.98 mm from the retina, and was seen to run up to a maximum power of 82 mW for the first model and 91 mW for the second model. To reduce heating of tissues, the device was extended by 0.5 mm to create an air gap which acted as an insulator. The temperature in the nearest living tissue then dropped below the prescribed limit of 2°C at 100 mW.

Outcome of Surgical Resection of Craniopharyngioma:Single Center 12 Years' Experience.

Background Craniopharyngiomas (CPs) are rare epithelial tumors arising from the Rathke's pouch remnant located along the path of the craniopharyngeal duct accounting for 1.2-4% of all primary intracranial brain tumors, the primary treatment of which is surgery. Objective Whether radical surgical resection or partial resection followed by radiotherapy is a topic of debate. We presented our 12 years single center experience on surgical resection of craniopharyngioma. Method This was a descriptive cross-sectional study conducted among forty-five patients who underwent transcranial resection of craniopharyngioma during a period of 12 years. Data were collected from medical record archives. Glassgow outcome score (GOS), electrolyte imbalance and visual complications were assessed as outcome measure. GOS > 3 was considered favorable while score ≤ 3 was considered unfavorable. Recurrence of tumors were analyzed. Result Out of 45 patients, 28 patients were male with male to female ration of 1.64. Mean age was 32.22±16.42 years. Supra-sellar craniopharyngioma were the most common location. Gross total resection was accomplished in 32 patients (71.1%) while subtotal resection among 13 patients (28.9%). Post-operative Diabetes Insipidus was developed among 35 patients (77.7%). Adamantinomatous craniopharyngioma was the most common histopathological type. Postoperative MRI with contrast was repeated to ascertain the completeness of resection. All patient with subtotal resection received radiotherapy. Follow up period ranged from 3 months to 8 years with mean of 4.2 years. Favorable outcome (GOS>3) was seen among 41 patients while unfavorable among 4 patients. Recurrence seen among 4 patients (8.9%). Overall mortality was 4 (8.8%). Conclusion Gross total excision of craniopharyngioma has a favorable outcome with acceptable morbidity.

Cheiro-Oral Syndrome.

Cheiro-Oral Syndrome (COS) is a very rare neurological syndrome associated with varied etiology. We report a 53-year-old man presented with left sided perioral and ipsilateral hand/fingers burning sensation for a one-month duration. On examination, he had hypesthesia over left perioral and distal palmar aspect of all five fingers. MRI revealed subacute infarct in the posterior limb of right internal capsule adjacent to and minimally involving thalamus. He was diagnosed as CheiroOral Syndrome as a result of ischemic stroke and managed.

Feasibility and efficacy of thrombolysis in acute ischemic stroke: A study from National Institute of Neurological and Allied Sciences, Kathmandu, Nepal.

BACKGROUND: Stroke is the major cause of morbidity and mortality worldwide. The number of stroke patients receiving recombinant tissue plasminogen activator (rt-PA), also known as Alteplase, in the developing world is extremely low. We aim to study the feasibility and efficacy of thrombolysis for the 1(st) time in our country. MATERIALS AND METHODS: In this retrospective study (July 2012-August 2015), acute ischemic stroke patients who were thrombolyzed within 3 h of stroke onset were included. Their demographic profiles, clinical profiles, risk factors, type of thrombolytic used, and outcomes were systematically recorded and analyzed. RESULTS: A total of 9 patients were thrombolyzed. The mean time from the onset of stroke symptoms to first dose of rt-PA (onset to treatment) was 1.2 h. Six patients had good neurological outcome as measured by modified Rankin Scale (mRS). The median mRS at discharge was 3. Thrombolysis-related post treatment complication was noted in 44.4%, of which nonfatal intracranial bleed occurred only in 2 patients (22.2%). None of the patients receiving intravenous tenecteplase had thrombolysis-related complications, and none of the patients had fatal intracranial bleed. CONCLUSION: This study clearly demonstrates the beginning of a feasible and effective thrombolysis in the treatment of acute ischemic stroke in Nepal.

Outcome of head injury patients undergoing surgical management: a tertiary level experience.

BACKGROUND: Head injury is the major cause of death in a neurosurgical patient. OBJECTIVE: To find the outcome, and treatment modality affecting the outcome in patients with head injury. METHODS: Nine hundred eighty seven patients presenting to National Institute of Neurological and Allied Sciences, Kathmandu, with head injury from September 2009 to October 2010 were included in the study. Patients were categorized according to post resuscitation Glasgow Coma Score. Outcome was assessed at discharge using Glasgow Outcome Score and analyzed for any correlation with modality of treatment and severity of injury. RESULTS: Among 987 patients with head injury,152 (15.4%) had severe, 126 (12.8%) had moderate and 709 (71.8%) had mild head injuries. Three hundred twelve (31.6%) patients required definitive and supportive surgical intervention. One hundred eighty two required cranial surgical intervention. Overall mortality was 10% (99), 137 patients (13.9%) had unfavorable outcome and 850 (86.1%) had favorable Glasgow Outcome Score of 4 and 5. Mortality was 53.2%, 9.5% and 0.8% in severe, moderate and mild head injury group respectively. Mortality rate was significantly higher (64.6%) in severe head injury group managed conservatively than those in same group treated with supportive and definite surgical intervention (44.8%) (p=0.016). CONCLUSION: Mortality in head injury patients depend upon severity of injury. Mortality in severe head injury group can be reduced by supportive and definite surgical intervention.