Use of memokath, a second generation urethral stent for relief of urinary retention in male spinal cord injured patients

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Abstract
Memokath (Engineers & Doctors A/S, Hornbaek, Denmark) a second generation urethral stent composed of titanium nickel alloy with shape memory effect was deployed in 10 male spinal cord injured patients with urinary retention. The stent was inserted under sterile conditions via a delivery catheter under fluoroscopic control in seven and with the aid of a flexible cystoscope in three. The proximal end of the stent was positioned at the bladder neck and 50 ml of normal saline at 45 °C was flushed through the stent which resulted in expansion of the distal most four coils of the stent in the proximal bulbar urethra; thus the internal sphincter (bladder neck) and external sphincter zone were kept open by the stent. Urethral stenting helped to achieve complete vesical emptying in all 10 patients. The complications included transient autonomic dysreflexia in two, transient urinary retention due to blood clot in one, and acute urinary tract infection in one patient. With a follow up of 3-7 months, all 10 patients have been aysmptomatic, with residual urine of less than 50 ml. There has been no migration or blocking of the stent. However, these stents require replacement at 12-18 months, but it is a short procedure as the Memokath, when cooled with saline at 4°C, becomes supersoft, enabling its easy and nontraumatic removal. As these stents produce no permanent effect upon the lower urinary tract and their removal is quick, safe and atraumatic, we prefer the second generation nickel titanium alloy stent to transurethral resection of bladder neck, external urethral sphincterotomy or permanent indwelling epithelialising stent, particularly in young spinal cord injured patients who wish to retain their fertility potential.