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Long-term result of Memokath urethral sphincter stent in spinal cord injury patients
© Vaidyanathan et al; licensee BioMed Central Ltd. 2002
Received: 30 August 2002
Accepted: 11 November 2002
Published: 11 November 2002
Memokath urethral sphincter stents are used to facilitate bladder emptying in patients with spinal cord injury, but long term follow-up has not been reported.
Case series of ten men with spinal cord injury who underwent insertion of Memokath stents and were followed for up to nine years.
Within four years, the stent had to be removed in nine out of ten patients because of: extensive mucosal proliferation causing obstruction to the lumen of the stent; stone around the proximal end of the stent, incomplete bladder emptying, and recurrent urinary infections; migration of the stent into the bladder related to digital evacuation of bowels; large residual urine; concretions within the stent causing obstruction to flow of urine, and partial blockage of the stent causing frequent episodes of autonomic dysreflexia. In one patient the stent continued to function satisfactorily after nine years.
The Memokath stent has a role as a temporary measure for treatment of detrusor-sphincter dyssynergia in selected SCI patients who do not get recurrent urinary infection and do not require manual evacuation of bowels.
We reported our preliminary experience of using the Memokath urethral stent to facilitate bladder emptying in ten men with spinal cord injury. . During follow-up of 3 to 7 months, results were satisfactory. This article reports extended follow-up of nine years.
Selection of patients
Men with spinal cord injury and urinary retention due to detrusor-sphincter dyssynergia were selected for insertion of a Memokath urethral sphincter stent. The exclusion criteria, inclusion criteria, technique for insertion and after care are discussed in our previous publication . All 10 men who underwent stenting achieved satisfactory bladder emptying and were followed for up to nine years.
Patient 1 developed difficulty in passing urine five months after stent insertion. Cystoscopy revealed mucosal oedema at the distal end of the stent. Fulguration of the prouting mucosal tissue was performed and he was able to pass urine satisfactorily. Four months later, he again developed difficulty in passing urine. Cystoscopy showed extensive mucosal proliferation, obstructing the stent. There was no encrustation and no stone. The stent was removed. Eight years later, this patient is using a penile sheath and supplementary intermittent catheterisation.
Patient 2 noticed spasms and sweating about four years after stent insertion. Ultrasound scan showed residual urine in the bladder and a large stone around the proximal end of the stent. Cystoscopy revealed stricture at the bulbo-membranous urethra. Suprapubic cystostomy was done and the stent was removed.
Patient 3 developed sweating and difficulty in emptying his bladder eight months after stent insertion. Flexible cystoscopy showed the stent lying in the bladder. Probably, digital bowel evacuation performed against the anterior wall of the rectum (and the urethra) caused upward migration of the stent. The stent was removed from the bladder endoscopically, and indwelling urethral catheter drainage was established.
Patient 4 was admitted nine months after stent insertion with sweating and a moderately large bladder. The stent was removed endoscopically. There was no calcification around the stent. A sacral anterior root stimulator was implanted.
Patient 5 developed difficulty in passing urine about a year after stent insertion while he was on holiday abroad. Multiple unsuccessful attempts were made to insert a catheter per urethra. Suprapubic cystostomy was performed. Five months later, cystoscopy showed multiple false passages in the urethra. Concretions were present over the stent. He underwent urethrotomy, division of external sphincter, and transurethral resection of the bladder neck.
Patient 6 developed progressive difficulty in bladder emptying seven months after insertion of a stent. The stent was removed with a cystoscope. During removal, the stent was found to be patent and in the proper position, with no concretions. This patient is now using intermittent catheterisation.
Patient 8 noticed intermittent partial obstruction of the stent about two years after it was inserted. During these episodes he experienced sweating. The stent was removed and a sacral anterior root stimulator was implanted.
It is possible that physicians using a new medical device or carrying out a new surgical procedure may be reluctant to publish their failures, as publication of complications may amount to admission of professional incompetence. Unless complications of a procedure are reported and information regarding potential complications is made available to other health professionals, a procedure may continue to be carried out by physicians without incorporating necessary modifications, thus compromising patients' safety. We favour voluntary reporting of all adverse events as they occur in the course of clinical practice in a spinal injuries centre. [2–5]. As we became aware of long-term complications of Memokath urethral sphincter stent, we stopped using Memokath stent in the Regional Spinal Injuries Centre, Southport. We believe that Memokath stent has a role as a temporary measure to cure detrusor-sphincter dyssynergia in selected SCI patients, who do not get recurrent urinary infection, and do not require manual evacuation of bowels.
We thank AstraZeneca (Ms Charlotte Lawledge), Pharmacia (Ms Joanne Thomas), and Shire Pharmaceuticals (Mr Patrick Tierney) for financial support, which enabled the Regional Spinal Injuries Centre, Southport, United Kingdom to become an institutional member of BioMed Central.
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