A comparison of retinal prosthesis electrode array substrate materials.

Simulations of artificial vision suggest that 1000 electrodes may be required to restore vision to individuals with diseases of the outer retina. In order to achieve such an implant, new technology is needed, since the state-of-the-art implantable neural stimulator has at most 22 contacts with neural tissue. A critical component of this system is the multi-channel, stimulating electrode array.

Finite element modeling of retinal prosthesis mechanics.

Epiretinal prostheses used to treat degenerative retina diseases apply stimulus via an electrode array fixed to the ganglion cell side of the retina. Mechanical pressure applied by these arrays to the retina, both during initial insertion and throughout chronic use, could cause sufficient retinal damage to reduce the device's effectiveness. In order to understand and minimize potential mechanical damage, we have used finite element analysis to model mechanical interactions between an electrode array and the retina in both acute and chronic loading configurations.

Effect of skin indentation on heat transfer during cryogen spray cooling.

Background And Objectives: Cryogen spray cooling (CSC) is used to pre-cool the epidermis during dermatological laser procedures such as treatment of port wine stain (PWS) birthmarks, hair removal, and non-ablative photorejuvenation. Thus far, heat transfer studies related to CSC optimization have assumed a flat surface but clinical observation suggests that human skin indents due to the force of an impinging cryogen spray.

Study Design/materials And Methods: High-speed videos of cryogen spray impingement on in vivo human skin were taken and the resulting indentations characterized as a function of both nozzle-to-skin distance and anatomic location.

Inguinal herniorrhaphy in the continuous ambulatory peritoneal dialysis patient.

Inguinal hernia repair in the patient on continuous ambulatory peritoneal dialysis (CAPD) is complicated in theory by an increased potential for recurrence. In addition to the constant increased intraabdominal pressure, chronic renal failure has been shown to impair tissue healing. Controversy exists regarding the waiting period before resuming CAPD postoperatively.