A bioresorbable urethral stent

Kemppainen, Esko; Talja, Martti; Riihelä, M; Pohjonen, Timo; Törmälä, Pertti; Alfthan, O

doi:10.1007/bf00590042

Cited by 108 publications

(37 citation statements)

References 9 publications

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“…IS Although some of these polypoid growths coalesce over the metal, the stent is not truly incorporated in the wall thickness because mucosal cells are still present on the ablu minal side of the stent. 16 Recently a bio resorbable urethral stent has been investi gated in rabbits by Kemppainen et al 17 The bioresorbable urethral stent is made of biodegradable self-reinforced poly-L-lactide to achieve an active initial tissue reaction and better tissue penetration. As the tissue reaction around the bioresorbable stent material is minimal, the chances of stenosis due to exuberant fibrotic proliferation re quiring endoscopic treatment which has been reported with the self-expandable urethral stent (wallstent) may be diminished in case of the bioresorbable stent.…”

Section: Discussionmentioning

confidence: 99%

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

1994

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Memokath (Engineers & Doctors A/S, Hornbaek, Denmark) a second genera tion 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, particu larly in young spinal cord injured patients who wish to retain their fertility potential.

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Section: Discussionmentioning

confidence: 99%

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

1994

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“…anterior urethra of the rabbit [1]. The SR-PGA spiral stent has been used in combination with visual laser…”

Section: Methodsmentioning

confidence: 99%

Effects of biodegradable self‐reinforced polyglycolic acid, poly‐dl‐lactic acid and stainless‐steel spiral stents on uroepithelium after Nd:YAG laser irradiation of the canine prostate

Pétas

Kärkkäinen

Talja

et al. 1997

British Journal of Urology

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Objective To evaluate the safety and tissue effects on canine uroepithelium and prostate of biodegradable self‐reinforced polyglycolic acid (SR‐PGA) and self‐reinforced poly‐dl‐lactic acid (SR‐PLA) spiral stents compared to stainless‐steel (SS) spiral stents. Material and methods Twenty‐five dogs (median body weight 12 kg) underwent a one‐stage midline laparotomy and cystotomy. A side‐firing Nd:YAG laser fibre was placed in the prostatic urethra antegradely and laser power applied at a setting of 20 W for 10 s in each side lobe, followed by dilatation to 4 mm diameter and insertion of a spiral stent. Dogs were randomized to receive an SR‐PGA, SR‐PLA or SS stent and no catheter was placed post‐operatively. The dogs were killed after a follow‐up of 1, 3 or 6 months and the bladder, prostate and urethra removed. Routine histological sections were prepared from the bladder, prostate, the proximal urethra immediately below the prostate and the distal urethra. Results Histological examination showed a mild to moderate foreign‐body reaction and an acute inflammatory reaction after 1 month in the SR‐PGA and the SR‐PLA groups. The tissue effect was minimal in the SR‐PGA group after 6 and 12 months. The SS stent group had more fibrosis, chronic inflammation and oedema at all follow‐up assessments. There were erosions of the epithelium with subepithelial oedema in the animals with the SS stent. No dysplasia was detected and some remnants of the suture material were evident in the area of the cystotomy closure. There was one stricture at the apex of prostate in the SR‐PGA group at 3 months in one re‐operated dog. Conclusion The histopathological changes in tissues caused by SR‐PGA and SR‐PLA stents were generally minor and decreased during the follow‐up. The biocompatibility of SR‐PGA and SR‐PLA stents was good when combined with Nd:YAG laser treatment of the prostate.

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“…Kemppainen et al 29 placed biodegradable self-reinforced stent made of poly-L-lactide (SR-PLLA) in 16 male rabbits after urethrotomy. In this report, authors concluded biodegradable SR-PLLA is promising material for a urethral stent to prevent re-stenosis of urethral strictures.…”

Section: Bioabsorbable Stentmentioning

confidence: 99%

Gastrointestinal Stent Update

Kang

2010

Gut Liver

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The use of self-expanding metallic stents in the upper gastrointestinal tract, placed under radiologic imaging or endoscopic guidance, is the current treatment of choice for the palliation of malignant gastrointestinal outlet obstructions. Advances in metallic stent design and delivery systems have progressed to the stage where this treatment is now considered a minimally invasive therapy. Metallic stent placement will broaden further into the field of nonsurgical therapy for the gastrointestinal tract. To date, metallic stents placed in the esophagus, gastric outlet, colorectum, and bile ducts are not intended to be curative, but rather to provide a palliative treatment for obstructions. The evolution of metallic stent technology will render such procedures not only palliative but also therapeutic, by enabling local drug delivery, and the use of biodegradable materials will reduce procedure-related complications. (Gut Liver 2010;4(Suppl. 1):S19-24)

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A bioresorbable urethral stent

Cited by 108 publications

References 9 publications

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

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

Effects of biodegradable self‐reinforced polyglycolic acid, poly‐dl‐lactic acid and stainless‐steel spiral stents on uroepithelium after Nd:YAG laser irradiation of the canine prostate

Gastrointestinal Stent Update

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