Memokath: a second generation of intraprostatic spirals.

Memokath (Engineers & Doctors A/S, Hornbaek, Denmark) is a new intraprostatic spiral composed of titanium nickel alloy with shape memory effect. We describe the use of this spiral in 30 consecutive patients with prostatic outflow obstruction. Their median age was 79 years and all were either in a high risk group for surgery or had refused surgery. The spiral was inserted under sterile conditions via a delivery catheter under ultrasonic guidance. When flushed with hot water (45 degrees C or above) one section of the spiral expands in the prostatic apex and maintains the spiral in position. When cooled with cold water (10 degrees C or below) the spiral becomes supersoft, making removal easy. With a follow-up of 0.2 to 9 months (median 3) we report a success rate of 83%. Five patients discontinued treatment, 3 because of urinary retention, 1 because of progressive obstructive symptoms and 1 following persistent urinary incontinence. No migration of the spiral was observed. Encrustations have appeared and seem to be a persistent problem. Most patients were satisfied with the procedure, which provided a quick, safe and effective method of relieving infravesical prostatic obstruction. Follow-up is short and late complications have yet to be assessed.