A novel temporary prostatic stent for the relief of prostatic urethral obstruction.

OBJECTIVES: To determine the effect of a novel temporary prostatic stent (The Spanner, AbbeyMoor Medical, Inc., Minnesota, USA) on variables of voiding function and quality of life among patients with prostatic urethral obstruction. PATIENTS AND METHODS: The stent design is very similar to the proximal 4-6 cm of a Foley catheter; this includes a proximal balloon to prevent distal displacement, a urine port situated cephalad to the balloon, and a reinforced stent of various lengths to span most of the prostatic urethra. There is also a distal anchor mechanism attached by sutures, and a retrieval suture which extends to the meatus and deflates the proximal balloon when pulled. The stent was inserted under topical anaesthesia in 30 patients. The maximum flow rate (Qmax), voided volume (W), postvoid residual (PVR), the International Prostate Symptom Score (IPSS) and stent position were assessed. RESULTS: Stents remained in situ for a mean (range) of 57 (1-98) days. The mean overall Qmax at baseline and after insertion were 8.2 and 11.6 mL/s, representing a 42% improvement (P < 0.001); the respective mean overall Ws were similar, at 219.7 and 221.6 mL (0.9% increase, not significant) and the PVRs were 312.1 and 112.3 mL, representing a 64% decrease (P = 0.004). The overall mean IPSS declined from 22.3 before to 7.1 after insertion, representing a 68% decrease (P < 0.001). There were only minor adverse events. The stability, patency and lack of migration of the device were confirmed radiographically up to 12 weeks of use. CONCLUSIONS: This early study shows that this temporary prostatic stent is easily inserted and removed, remains anchored in position, and significantly improves the Qmax, PVR and IPSS while preserving volitional voiding and continence.

Transurethral hot-water balloon thermoablation for benign prostatic hyperplasia: patient tolerance and pathologic findings.

OBJECTIVES: To determine the patient tolerance and thermal ablation pattern in human prostatic tissue after treatment with a hot water, catheter-based system. METHODS: Twenty-seven men scheduled for surgery for symptomatic benign prostatic hyperplasia or adenocarcinoma of the prostate underwent water-induced thermotherapy. The patients were randomly assigned to one of four treatment groups. Lidocaine gel was the sole means of pain control. The patients and an observer recorded patient discomfort during therapy. A Foley catheter was left in place until surgery (n = 13) or successful voiding (n = 14). Prostates were subsequently enucleated or removed, whole mounted, and examined. RESULTS: Patients reported mild treatment discomfort, the level of which did not correlate with the extent of necrosis, balloon diameter, or water temperature (all P >0. 05). Distal penile burning was the most commonly reported discomfort. All 14 patients successfully voided within 12 days of treatment. Prostates were enucleated (n = 24) or removed (n = 3) at a mean of 27 days (range 4 to 120) after thermotherapy, except for a single adenectomy 17 months after therapy. Pathologic findings included periurethral hemorrhagic necrosis, with focal or extensive urothelial denudation and mild inflammation. The mean maximal depth of necrosis from the urethral lumen was 7, 9, 10.33, and 11 mm in groups 1, 2, 3, and 4, respectively. The extent of necrosis was similar in all groups (P = 0.11), regardless of the water temperature; conversely, the balloon diameter correlated with the depth of necrosis (P = 0.024). CONCLUSIONS: This system of tissue ablation appears to be well tolerated, and it produced consistent pathologic results.

Intrarenal distribution of flow during perfusion.

Intrarenal flow distribution in ischemic and nonischemic dog kidneys has been studied using the 133Xe washout technique and angiography. These preliminary studies showed two different hemodynamic alterations during perfusion, vasoconstriction, and diminution of cortical flow. Vasoconstriction of the renal artery and branches noted in both groups was observed to be a reversible phenomenon and disappeared within 1 hr of perfusion. A decrease in cortical flow was also seen at the beginning of perfusion in both groups, being much more severe in the ischemic group. Significant improvement in cortical flow was noted during the 1st hr of perfusion by both angiographic and washout techniques. This was most pronounced in the nonischemic group. The determination of flow distribution by 133Xe washout technique appears to correlate well with concomitant angiography. Future studies directed toward modification of preservation methods to minimize these changes may well lead to improvement of the present state of renal preservation.