Klaus-Peter Jünemann

Recovery of erectile function after nerve-sparing radical prostatectomy: improvement with nightly low-dose sildenafil.

To evaluate the effect of low‐dose sildenafil for rehabilitating erectile function after nerve‐sparing radical prostatectomy (NSRP), as the delay to recovery of erectile function after NSRP remains under debate.

Functional Outcome Following Photoselective Vaporisation of the Prostate (PVP): Urodynamic Findings Within 12 Months Follow-Up

OBJECTIVES We determined the impact of potassium-titanyl-phosphate (KTP) laser therapy of the prostate on urodynamic results, voiding function, quality of life, and sexual function. DESIGN, SETTING, AND PARTICIPANTS Forty-five patients complaining of symptomatic benign prostatic hyperplasia (BPH) and urodynamically proven obstructive voiding were included in the prospective study. Follow-up exams were repeated 3 mo and 12 mo after the treatment. INTERVENTION All patients underwent photoselective 80-Watt KTP laser vaporisation of the prostate performed by two experienced surgeons. MEASUREMENTS Disease-specific quality of life and sexual function were assessed using the International Prostate Symptom Score (IPSS) and International Inventory of Erectile Function (IIEF). Video-urodynamics were carried out to determine changes in pressure flow and bladder function. RESULTS AND LIMITATIONS The average preoperative prostate volume was 47.63 ml (range 30-75 m). The mean preoperative PSA-value, which had been 3.5 ng/ml (range 0.13-7 ng/ml) initially, dropped by 34.2% after 3 mo and 37.1% after 12 mo. Despite transient micturition complaints (40%), all patients showed significant improvement in the IPSS in urinary peak flow and detrusor pressure at peak flow. The mean post-void residual urine volume decreased, while erectile function and libido scores remained unaffected by the procedure according to the IIEF. Detrusor contractility was also not affected in any of the patients. The single-centre study design and small number of patients may have limited the study results. CONCLUSIONS KTP laser therapy of the prostate achieves significant improvements both symptomatically as well as with respect to objective micturition parameters. The procedure leads to a functional deobstruction of the lower urinary tract with steady improvement results throughout the follow up period.

Experimental basis of shockwave-induced renal trauma in the model of the canine kidney.

SummaryUsing the new electromagnetic shockwave source of the Modulith SL 20 shockwave-induced renal trauma was evaluated by acute and chronic studies in the the canine kidney model. In a further study the electromagnetic shockwave source of the Lithostar Plus Overhead module was tested. Overall, 92 kidneys were exposed to shock waves coupled either by water bath (Modulith lab type) or by water cushion (Modulith prototype, Lithostar Overhead) under ultrasound localization. The generator voltage ranged between 11 and 21 kV, the number of impulses between 25 and 2500. After application of 1500/2500 shocks the extent of the renal lesion depended strictly on the applied generator voltage and was classified into 4 grades: Grade 0, no macroscopic trauma detectable (at 11–12 kV); grade 1, petechial medullary bleeding (at 13 kV); grade 2, cortical hematoma (at 14–16 kV); and grade 3, perirenal hematoma (17–20 kV). Whereas at low and medium energy levels the number of shocks played only a minor role, at maximal generator voltage (20 kV) even 25 impulses induced a grade 2 and 600 shocks a grade 3 lesion, emphasizing the importance of shockwave limitation in the upper energy range. In shockwave-induced renal trauma a vascular lesion was predominant and cellular necrosis was secondary. Coupling with a water cushion resulted in a 15%–20% decrease in the disintegrative and traumatic effect, which was compensated for by increasing the generator voltage by 2 kV. Long-term studies showed complete restitution following grade 1 and 2 trauma, whereas after a grade 3 lesion a small segmental and capsular fibrosis without hyperplasia of the juxtaglomerular apparatus was observed. Based on the characteristic ultrasound pattern found in the first study, the threshold for induction of grade 1 lesion was investigated. With both lithotripters a wide range for induction of a grade 1 lesion (Modulith 234–411, Lithostar Plus 220–740) and also a significant overlapping with grade 0 and 2 lesions was seen at low energy settings (levels 2–4). In contrast, the range of shocks (Modulith 96–150, Lithostar Plus 90–142) and overlapping was minimal when high energy was used (levels 7–9). Finally, the disintegration-trauma coefficient combining the results obtained in a standard stone model with those of the canine kidney model was introduced.

Neuroanatomy and clinical significance of the external urethral sphincter.

Although the topographic muscular architecture of the pelvic floor is essentially understood, its nerve supply and functional anatomy remain controversial. We therefore dissected 3 male human cadavers by tracing the entire sacral plexus and the pudendal nerve from the cada equina down to their final destination. Our anatomic dissection demonstrated that the voluntary external urethral sphincter mechanism is augmented by two separate muscular components: the levator ani and the transversus perinei muscle. Urodynamic findings with sacral neurostimulation support our anatomic description.

Nocturnal tumescence: a parameter for postoperative erectile integrity after nerve sparing radical prostatectomy.

PURPOSE The exact process and time required for rehabilitation of erectile function after nerve sparing prostatectomy remain unclear to date. Different theories of the pathophysiology of postoperative erectile dysfunction are currently being discussed. In a prospective study we performed recordings of nocturnal penile tumescence and rigidity during the acute phase after nerve sparing radical prostatectomy, ie in the first night after removal of the catheter, to assess the organic penile integrity. MATERIALS AND METHODS In 27 patients with local prostate carcinoma who had been sexually active before the intervention, we performed unilateral or bilateral nerve sparing radical prostatectomy. Preoperative sexual function of all patients was evaluated by the International Index of Erectile Function-5 questionnaire. On the day of catheter removal (postoperative day 7 to 14) an NPTR recording was performed on the following night with an erectometer (RigiScan). RESULTS All patients had a preoperative IIEF score greater than 18. After removal of the catheter 25 of 27 patients (93%) showed 1 to 5 nocturnal rigidity increases by greater than 70% for at least 10 minutes. In a control group of 4 patients who underwent radical prostatectomy without nerve sparing, no nocturnal erections were recorded. CONCLUSIONS NPTR recording during the acute phase after nerve sparing radical prostatectomy showed residual erectile function as early as the first night after catheter removal. These results are significant for selecting adequate pharmacological treatment for optimal therapy and rehabilitation of satisfactory erections and sexual function. In cases of early nocturnal tumescence, application of a PDE5 inhibitor can support successive organ rehabilitation. However, if tumescence does not occur, penile injection therapy is recommended.

LONG-TERM FOLLOWUP AND SELECTION CRITERIA FOR PENILE REVASCULARIZATION IN ERECTILE FAILURE

PURPOSE We report the long-term results of penile revascularization surgery for erectile failure and suggest possible selection criteria for this controversial surgical procedure. MATERIALS AND METHODS In 7 years 62 impotent men who did not respond to pharmacotherapy underwent microsurgical penile revascularization and completed long-term followup evaluation in 41 months (range 18 to greater than 62) consisting of a detailed questionnaire, duplex sonography and optional pharmacotherapy or angiography. The Virag procedure was chosen for the first 7 patients, the original Hauri technique for the next 13 and the modified Mannheim triple anastomosis for 42. RESULTS Of all patients 34% achieved spontaneous and another 20% pharmacologically induced erections. Success in diabetics and older patients was lower (43% for diabetics, 39% for those older than 50 years at surgery), while it was high in men with less than 2 risk factors (58%) as well as in younger patients (69% for those up to 50 years old). Shunt patency was 92%. Complications such as glans hyperemia developed in 13% of patients, shunt thrombosis in 8% and inguinal hernias in 6.5%. CONCLUSIONS Patient selection is vital for the successful outcome of penile revascularization surgery. We adhere to strict selection criteria, such as patient age maximum of 50 years, less than 2 risk factors, no recent diabetes and termination of nicotine abuse. Penile revascularization surgery is highly indicated in this group of patients, especially since it is the only causal therapy for erectile failure.

Neurophysiology of penile erection

SummaryIn 6 dogs and 6 monkeys electrical stimulation of the cavernous, pudendal and hypogastric nerve was performed to gain better understanding of the erectile neurophysiology. Arterial flow, intracorporeal pressure and venous restriction studies during single and combined neurostimulation demonstrated that initiation and maintenance of erection is a parasympathetic phenomenon. Penile rigidity however, could only be achieved with additional pudendal nerve stimulation resulting in muscular compression of the blood distended cavernous bodies. Detumescence or subsidence of erection is primarily under sympathetic control, due to inhibition of sinusoidal smooth muscle relaxation. On the basis of our observations we conclude that penile erection is dependent upon three neurophysiological mechanisms: 1. the parasympathetic “vascular mechanism”, the somatomotor “muscular mechanism” and the sympathetic “inhibitory mechanism”.

Comparison of urodynamic findings and response to oxybutynin in nocturnal enuresis.

Sixty-three children with persistent nocturnal enuresis were urodynamically assessed and subsequently treated with oxybutynin chloride. Urodynamic evaluation, including graduation of detrusor instability and comparison of maximum bladder capacity with the age-predicted norm, confirmed an inadequate storage function in 84% of the children. Treatment benefit totaling 70% was dependent upon urodynamic findings, with best relation to the determined bladder capacity. The value attributed to graduation of uninhibited contractions was prognostic in accordance with further subdivision of the maximum bladder capacity. Treatment benefit was limited in children with normal urodynamic findings.

Effects of acute urinary bladder overdistension on bladder response during sacral neurostimulation

Objective: Urinary retention and micturition disorders after overdistension are clinically well-known complications of subvesical obstruction. We attempted to evaluate whether bladder overdistension influences bladder response and whether overdistension supports detrusor decompensation. Methods: Following lumbal laminectomy in 9 male foxhounds, the sacral anterior roots S2 and S3 were placed into a modified Brindley electrode for reproducible and controlled detrusor activation. The bladder was filled in stages of 50 ml from 0 to 700 ml, corresponding to an overdistension. At each volume, the bladder response during sacral anterior root stimulation was registered. After overdistension, the bladder was refilled stepwise from 0 to 300 ml and stimulated. Results: In all dogs, the bladder response was influenced by the intravesical volume. The maximum pressure (mean 69.1 cm H2O) was observed at mean volume of 100 ml. During overdistension, a significant reduction in bladder response of more than 80% was seen. After overdistension, a significant reduction in intravesical pressure of 19.0% was observed. In 2 cases, reduction in bladder response was more than 50% after a single overdistension. Conclusions: We conclude that motoric bladder function is influenced during and after overdistension. A single bladder overdistension can support acute and long-lasting detrusor decompensation. In order to protect motoric bladder function, bladder overdistension must be prevented.

The effect of impaired lipid metabolism on the smooth muscle cells of rabbits

SummaryOur clinical data enabled us to demonstrate a correlation between impaired lipid metabolism and vasculogenic impotent men. Our aim was to evaluate the effect of an impaired lipid metabolism on the smooth muscle of the corpus cavernosum. A total of 16 rabbits were given a cholesterol-enriched diet for 3 months, and 8 of these received additional thromboxane A2 receptor antagonist; 10 other rabbits (control) were fed a normal diet. Subsequently, cavernous tissue biopsies were taken, and tissue lipid extractions and electron microscopic evaluation were made from 3 rabbits in each group. In the untreated high-cholesterol diet group, cholesterol levels reached approx. 2.1 μg/mg body weight compared with 1.07 μg/mg b.wt. in the thromboxane A2 receptor antagonist-treated group and elevated levels compared with control group. Similar results were found for the triglyceride and free fatty acid levels. Lecithin tissue levels in treated rabbits were distinctly elevated against those of other 2 groups. Ultramorphological examination of the control group disclosed normal smooth muscle cell (SMC) architecture with numerous sites of intercellular contacts. These findings contrasted with those of the high-cholesterol diet groups which showed significant SMC degeneration with loss of intercellular contacts. Our data imply that impaired lipid metabolism causes cavernous SMC degeneration which plays a major role in the pathogenesis of erectile dysfunction. The thromboxane A2 receptor antagonist seems to produce a protective metabolic effect on the erectile tissue which may have some consequences future treatment strategies.