Long-term effectiveness of sacral nerve stimulation for refractory urge incontinence.

OBJECTIVES: To evaluate the long-term efficacy of sacral nerve stimulation for refractory urinary urge incontinence. STUDY DESIGN AND METHODS: Urge incontinent patients qualified for surgical implantation of a neurostimulator system after trial screening with percutaneous test stimulation. Surgical implantation of the InterStim System (Medtronic Inc., Minneapolis, Minn., USA) was performed in cases where a >50% reduction in incontinence symptoms was documented during the 3- to 7-day test stimulation period. The InterStim System consists of an implantable pulse generator, a transforamenally placed quadripolar lead, and an extension that connects these two devices for unilateral stimulation of the S3 or S4 sacral nerve. Efficacy for 96 implanted patients was based on urinary symptom changes as quantified in voiding diaries collected at baseline and annually after surgical implantation. RESULTS: As compared to baseline, the group of 96 implanted patients demonstrated significant reductions in urge incontinent symptoms at an average of 30.8+/-14.8 (range 12-60) months with respect to the number of urge incontinent episodes per day, severity of leaking, and the number of absorbent pads/diapers replaced per day due to incontinence (all p<0.0001, respectively). Gender, pretreatment variables, and age were not found to be relevant factors that affected these results. 11 of the 96 patients underwent device explant due to lack of efficacy, pain or bowel dysfunction. These data were conservatively included in the efficacy results. No permanent injuries associated with the devices or therapy were reported. CONCLUSION: Sacral nerve stimulation is an effective treatment for refractory urge incontinence with sustained long-term benefit through an average of 30.8 months.

Modeling of frequency doubling and tripling with measured crystal spatial refractive-index nonuniformities.

Efficient frequency doubling and tripling are critical to the successful operation of inertial confinement fusion laser systems such as the National Ignition Facility currently being constructed at the Lawrence Livermore National Laboratory and the Omega laser at the Laboratory for Laser Energetics. High-frequency conversion efficiency is strongly dependent on attainment of the phase-matching condition. In an ideal converter crystal, one can obtain the phase-matching condition throughout by angle tuning or temperature tuning of the crystal as a whole. In real crystals, imperfections in the crystal structure prohibit the attainment of phase matching at all locations in the crystal. We have modeled frequency doubling and tripling with a quantitative measure of this departure from phase matching in real crystals. This measure is obtained from interferometry of KDP and KD*P crystals at two orthogonal light polarizations.

Sacral neuromodulation in the treatment of urgency-frequency symptoms: a multicenter study on efficacy and safety.

PURPOSE: Neuromodulation of sacral nerves has shown promising results in correcting voiding dysfunction. We report the results of a multicenter trial designed to assess the efficacy of sacral nerve neuromodulation in patients presenting with refractory urinary urgency-frequency. MATERIALS AND METHODS: A total of 51 patients from 12 centers underwent baseline assessment, including a detailed voiding diary, urodynamic evaluation and percutaneous test stimulation of the sacral nerves at S3 and/or S4. All patients enrolled in the study had undergone prior conventional treatment, such as pharmacotherapy, hydrodistention and surgical intervention, which failed. All patients demonstrated a satisfactory response to trial stimulation and were randomly divided into a stimulation group (25 patients) and a control group (26). A sacral nerve stimulation device was implanted after 6 months in the control group. Patients were followed at 1, 3 and 6 months, and at 6-month intervals for up to 2 years after implantation of a neuroprosthetic InterStim* system. dagger The study variables included the number of voids daily, volume voided per void and degree of urgency before void. RESULTS: Compared to the control group, 6-month voiding diary results demonstrated statistically significant improvements (p <0.0001) in the stimulation group with respect to the number voids daily (16.9 +/- 9.7 to 9.3 +/- 5.1), volume per void (118 +/- 74 to 226 +/- 124 ml.) and degree of urgency (rank 2.2 +/- 0.6 to 1.6 +/- 0.9). Patients in the control group showed no significant changes in voiding parameters at 6 months. Significant improvements in favor of the stimulation group were noted in various parameters with respect to water cystometry and quality of life (SF-36). At 6 months after implant, neurostimulators were turned off in the stimulation group and urinary symptoms returned to baseline values. After reactivation of stimulation sustained efficacy was documented at 12 and 24 months. CONCLUSIONS: Neuromodulation of the sacral nerves is an effective, safe therapy that successfully treats significant symptoms of refractory urgency-frequency.

Spatial filter pinhole development for the national ignition facility.

We present results from a major experimental effort to understand the behavior of spatial filter pinholes and to identify and demonstrate a pinhole that will meet the requirements of the National Ignition Facility (NIF). We find that pinhole performance depends significantly on geometry and material. Cone pinholes are found to stay open longer and to cause less backreflection than pinholes of more conventional geometry. We show that a +/-150-microrad stainless-steel cone pinhole will pass a full-energy NIF ignition pulse with required margins for misalignment and for smoothing by spectral dispersion. On the basis of a model fitted to experimental results, a +/-125-microrad stainless-steel cone pinhole is also projected to meet these requirements.

Measurement of thermal effects on the optical properties of prostate tissue at wavelengths of 1,064 and 633 nm.

BACKGROUND AND OBJECTIVE: The extent of thermal injury during laser prostatectomy is dependent on the light distribution in laser-irradiated tissue. As tissue is irradiated, the optical properties change as a function of temperature due to an alteration of molecular and cellular structure. The purpose of the present study was to determine how the exposure of both fresh and previously frozen canine prostate tissue to elevated temperatures affects the optical properties. STUDY DESIGN/MATERIALS AND METHODS: Optical properties were measured by using a double integrating sphere spectrophotometer with an inverse adding-doubling algorithm. Measurements were made at two wavelengths (1,064 nm and 633 nm) on samples heated in a waterbath in 5 degree-10 degree increments for 10 min through a 50 degrees C temperature range. RESULTS: Upon coagulation, the absorption coefficient of fresh tissue decreased from the baseline measurement for both wavelengths (0.027 +/- 0.003 to 0.019 +/- 0.002 for lambda = 1,064 nm; 0.073 +/- 0.007 to 0.061 +/- 0.006 for lambda = 633 nm). However, the scattering coefficient increased sharply from the baseline measurement following coagulation (3.06 +/- 0.26 to 6.05 +/- 0.29 for lambda = 1,064 nm; 4.89 +/- 0.23 to 7.22 +/- 0.30 for lambda = 633 nm). Thermal coagulation occurred during exposure to temperatures between 60 degrees C and 70 degrees C. CONCLUSION: Data obtained in this study indicate that thermal coagulation of tissue alters the optical properties. The extent to which these changes occur was found to be dependent on wavelength and freshness of tissue. These results are significant because they suggest how thermally induced changes in the optical properties may limit the depth of light penetration in tissue thus compromising treatment.

Long, narrow all-light atom guide.

A 1-mm-diameter all-light atom guide capable of transporting ultracold atoms tens of centimeters with high efficiency is described. We made the atom tunnel, a dark hollow beam that is blue detuned from resonance, by passing a few tens of milliwatts of energy from a TEM(00) diode laser beam through an optical sequence composed of three axicons and a simple lens. We demonstrate transport of 10(8)Cs atoms approximately 20 cm with minimal heating. We show that it is possible for one to control the direction and speed of the atoms in the tunnel by varying the detuning of the tunnel beam.

Review and assessment of measured values of the nonlinear refractive-index coefficient of fused silica.

The literature describes more than 30 measurements, at wavelengths between 249 and 1550 nm, of the absolute value of the nonlinear refractive-index coefficient of fused silica. Results of these experiments were assessed and best currently available values were selected for the wavelengths of 351, 527, and 1053 nm. The best values are (3.6 ? 0.64) x 10(-16) cm(2)/W at 351 nm, (3.0 ? 0.35) x 10(-16) cm(2)/W at 527 nm, and (2.74 ? 0.17) x 10(-16) cm(2)/W at 1053 nm.

Nonlinear holographic imaging of phase errors.

Experimental measurements and computer simulations of nonlinear holographic imaging of phase errors in laser beams are presented. The computer models are found to accurately predict the results of the experiments. Comparison with similar results by use of amplitude scatterers reveals that the image location (along the propagation path) is the same for phase and amplitude scatterers. However, the intensity and fluence of the image of a phase scatterer are significantly larger, indicating that phase objects pose a larger damage threat to optical components.

Multicrystal designs for efficient third-harmonic generation.

Efficient frequency tripling of high-fluence, narrow-band laser pulses is routinely accomplished with a doubling crystal and a sum-frequency mixer. The addition of a second mixer can dramatically improve conversion efficiencies for the large bandwidths of interest for inertial confinement fusion. Designs that involve two doublers similarly offer a higher dynamic range of conversion efficiency versus intensity than the usual two-crystal design.

Evaluation of renal resistive index, maximum velocity, and mean arterial flow velocity in a hydronephrotic partially obstructed pig model.

RATIONALE AND OBJECTIVES: The authors investigate, in a controlled pig model, the usefulness of Doppler sonographic measurements of resistive index (RI), maximum velocity (Vmax), and mean velocity (Vmean) in diagnostic evaluation of the partially obstructed kidney. METHODS: Seven female pigs underwent surgical partial unilateral renal obstruction at the ureteropelvic junction. Doppler parameters of RI, Vmax, and Vmean were measured preoperatively and postoperatively in obstructed and contralateral nonobstructed kidneys. The General Linear Model multivariate analysis of variance was used for statistical analysis of data. RESULTS: There was no significant difference in the preoperative control values of RI (P = 0.71), Vmax (P = 0.27), and Vmean (P = 0.12). There was a statistically significant decrease in the Vmax and Vmean after postoperative day 5 in the obstructed kidney compared with the contralateral nonobstructed kidney (P = 0.01 and 0.03, respectively). There was no statistically significant difference in RI during the study. CONCLUSIONS: In this study, RI was not a reliable indicator of partial renal obstruction. Measurements of maximal and mean blood flow velocities reached discriminatory significance only after the fifth postobstructive day, proving insensitive in the immediate postobstructive period. Vmax and Vmean demonstrated a decrease in the partially obstructed renal collecting system after 5 days of obstruction and may serve as useful parameters in the evaluation of obstruction after the immediate acute period, when compared with a nonobstructed contralateral system.

Perturbation theory for electric-field amplitude and phase ripple transfer in frequency doubling and tripling.

A theory is presented for the transfer of a perturbation of the electric field from the input to the output of a frequency converter. The transfer relationship for the field ripple is shown to depend on the plane-wave operating parameters of the converter. Predictions of the theory are shown to be in excellent agreement with full numerical simulations of doubling and tripling and experiments measuring ripple transfer in frequency doubling.

Nonlinear formation of holographic images of obscurations in laser beams.

Computer models are used to simulate the nonlinear formation of images of obscurations in laser beams. The predictions of the model are found to be in good agreement with measurements conducted in the nonlinear regime corresponding to a typical solid-state laser operation. In this regime, peak-to-mean fluence ratios large enough to induce damage in optical components are observed. The amplitude of the images and their location along the propagation axis are accurately predicted by the simulations. This indicates that the model is a reliable design tool for specifying component staging and optical specifications to avoid optical damage by this mechanism.

Techniques of coagulation laser prostatectomy for narrow divergence angle fibers.

Although laser prostatectomy has become an accepted technique for the treatment of obstructive prostatism, considerable debate remains about which laser prostatectomy method to use in various treatment situations. This article discusses the different methods of noncontact side-firing coagulation laser prostatectomy using narrow divergence angle fibers (< 30 degrees). Static treatment strategies that have been successfully employed with widely divergent beams are not appropriate for fibers producing narrow divergence angle beams. Narrow divergence angle beams produce a small diameter spot on the prostatic urethra and far larger power density. Additionally, neodymium/yttrium aluminum garnet light scatters relatively poorly within prostatic tissue. Most light continues along the path of through transmission until ultimate tissue absorption and conversion into heat. The width and total volume of the coagulated lesion is therefore limited when using a narrow divergence angle fiber to produce static lesions. Probe movement is essential. Rapid (> 2 mm/s) probe movement produces only superficial coagulation. An initial dwell period of approximately 3 s is also important to maximize coagulated tissue volume. Scanning strategies where the fiber is moved through the prostatic urethra in longitudinal and radial directions are discussed and compared. Radial and longitudinal scanning methods produce similar coagulation defects. Treatment using a rocking motion within a limited volume of tissue may increase coagulation depth. No technique is ideal for all clinical situations. Vaporization prostatectomy or contact laser transurethral incision of the prostate is appropriate for primary treatment of glands < 30 g or as adjunctive therapy to facilitate early catheter removal. Alternative treatment methods are compared to noncontact coagulation prostatectomy.

The Hytrin Community Assessment Trial study: a one-year study of terazosin versus placebo in the treatment of men with symptomatic benign prostatic hyperplasia. HYCAT Investigator Group.

OBJECTIVES: To determine the clinical effectiveness and safety of alpha(1)-blockade therapy versus placebo in the treatment of men with moderate to severe symptoms of prostatism in a community-based population under usual care conditions. METHODS: The Hytrin Community Assessment Trial is a prospective, placebo-controlled, randomized, double-blinded, 1-year clinical trial, conducted at 15 academic medical centers (regional sites) and 141 private urology practices (satellite sites). A total of 2084 men at least 55 years old with moderate to severe symptoms of benign prostatic hyperplasia (BPH) as determined by an American Urological Association (AUA) Symptom Score (AUA-SS) of 13 or more points and a bother score (AUA-BS) of 8 or more were enrolled. Randomized patients at regional sites were required to have a peak urinary flow rate less that 15 mL/s with voided volume of at least 150 mL. Treatment with terazosin was initiated with 1 mg daily for 3 days, followed by 2 mg daily for 25 days. Thereafter, patients were titrated stepwise to 5 or 10 mg if they failed to achieve a 35% or greater improvement in the AUA-SS. Primary outcome measures were AUA-SS, AUA-BS, BPH Impact Index (BII), disease-specific quality of life (QQL) score, and treatment failure as defined as discontinuation due to persistent or worsening symptoms or need for surgical intervention for BPH. Secondary outcome measures were peak urinary flow rate and postvoid residual urine volume. RESULTS: AUA-SS (0 to 35 point scale) improved from a baseline mean of 20.1 points by 37.8% during terazosin (n=976) and by 18.4% during placebo (n=973) treatment (P<0.001). Similarly, statistically superior improvements were observed in regard to the AUA-BS, BII, and the QQL score in the terazosin-treated patients. Peak urinary flow rate improved from a baseline of 9.6 mL/s (both regional treatment groups) by 2.2 mL/s in the terazosin group (n=137) and by 0.7 mL/s in the placebo group (n=140) (P< or = 0.05). Treatment failure occurred in 11.2% of terazosin- and 25.4% of placebo-treated patients (P<0.001; Kaplan-Meier adjusted withdrawal rates of 365 days). Withdrawal from study drug treatment due to adverse events occurred in 19.7% of terazosin- and 15.2% of placebo-treated patients (P<0.001). CONCLUSIONS: Terazosin given once daily in a dose ranging from 2 to 10 mg in community-based urology practices under conditions simulating usual care is effective in reducing the symptoms, perception of bother, and the impairment of QQL due to urinary symptoms in men with moderate to severe symptoms of prostatism. This effect is superior to placebo and maintained over 12 months of follow-up. Clinical research outcome studies in BPH can be conducted in community-based practices, thus simulating as closely as possible "usual care" conditions.

Evaluation and management of the urologic consequences of neurologic disease.

Neurologic disorders create important functional urinary tract abnormalities. Loss of bladder reflex inhibition and coordination due to neurologic disease or injury to higher centers may lead to morbidity such as recurrent urinary tract infection, hydronephrosis, urinary tract stones and loss of renal function. This paper discusses neurogenic bladder disease using a descriptive urodynamic format. The importance of detrusor hyperreflexia and internal and external sphincter dyssynergia are discussed in detail. Finally, a practical clinical management plan is discussed for patients with urologic dysfunction due to cerebrovascular accident, Parkinson's disease, multiple sclerosis, spinal cord injury, and peripheral neuropathy.

The effect of zanoterone, a steroidal androgen receptor antagonist, in men with benign prostatic hyperplasia. The Zanoterone Study Group.

PURPOSE: Zanoterone (100 to 800 mg.) versus placebo was studied in 463 patients with benign prostatic hyperplasia. MATERIALS AND METHODS: Study end points were maximum urinary flow rate, American Urological Association symptom index, prostate volume, prostate specific antigen and sex steroid concentrations after 6 months of treatment. RESULTS: Mean increases in maximum urinary flow rate were 2 to 3-fold over placebo, although only the 200 mg. group had significant results (1.7 ml. per second, p = 0.026). There were no statistically significant differences between the zanoterone and placebo groups in symptom index or prostate volume. Estradiol and testosterone concentrations, and the incidence of breast pain and gynecomastia increased significantly with zanoterone compared with placebo. Prostate specific antigen levels decreased significantly. CONCLUSION: Zanoterone did not demonstrate a favorable risk-to-benefit profile for the treatment of benign prostatic hyperplasia.

Prevention and treatment of incontinence after radical prostatectomy.

Postoperative complications after radical prostatectomy have only recently been studied in a formal prospective manner. A survey of existing literature yields widely disparate rates of postoperative incontinence. Classically, about 5% of patients were believed to be incontinent. More recent studies that involve patient questionnaires and a specific continence history indicate that nearly 30% of patients experience some urinary leakage with activity. Evolving new operative techniques such as modified apical dissection and construction of a tubularized neourethra have potential to improve continence rates considerably. Patients who do experience urinary incontinence should be offered appropriate evaluation and treatment. In addition to cystourethroscopy, all patients should undergo cystometry and Valsalva leak-point testing to differentiate sphincteric dysfunction from detrusor instability. Injection of bovine cross-linked collagen into the preexternal sphincter zone or implantation of the artificial urinary sphincter are options for treatment of intrinsic sphincter dysfunction. Detrusor instability is best treated with pharmacotherapy. This article discusses the details of prevention, evaluation, and treatment of postprostatectomy incontinence.

Laser prostatectomy devices and their tissue effects.

Laser systems used for prostatectomy may be right-angle (sidefiring) devices, which are either refractive or reflective, or contact devices. The tissue physics of these systems differ, and as a result, there are very real differences in the optimal exposure techniques. An understanding of the device being used is essential for producing a satisfactory result.

Intrapelvic pressure monitoring in the partially obstructed porcine kidney.

OBJECTIVES: The diagnosis of urinary obstruction in newborns and infants remains difficult because the diagnostic studies available at present are fraught with many problems. It is our premise that precise measurement of renal pelvic pressures under physiologic conditions in patients with urinary tract dilation will allow diagnosis of obstruction and prediction of further renal damage. This study evaluates an intrapelvic pressure monitoring system. METHODS: Four porcine subjects had partial ureteropelvic junction obstruction created surgically; two subjects were used as controls. Doppler ultrasound and MAG-3 furosemide renography were performed preoperatively and each week pressures were measured with a Millar 5 F solid-state pressure transducer and the analog signals were converted on line to digital information to allow signal processing and later data analysis. Antegrade nephrostograms were obtained at the same sitting and showed that the model remained stable over time. Measurements were obtained at physiologic flow rates as well as at the standard Whitaker infusion rate of 10 cc/min. RESULTS: Thirteen pressure studies were performed on 9 kidneys. Each study was classified as normal (4), partial obstruction (8), or total obstruction (1), based on ultrasound and nephrostogram criteria. The normal units had baseline pressures of 4.12 +/- 0.94 cm water (H2O), which increased to 9.12 +/- 1.38 cm H2O with infusion. In the partially obstructed group, baseline was 16.4 +/- 3.83 cm H2O and increased to 35.3 +/- 15.9 cm H2O with infusion. The kidney with total obstruction showed a baseline pressure of 27 cm H2O, which increased to 68 cm H2O with infusion. These pressure measurements were also compared to furosemide renography. CONCLUSIONS: Intrapelvic pressures correlated well with conventional ultrasound and nephrostogram in the evaluation of partial obstruction. However, the results of furosemide renography and the Whitaker test were quite variable and did not accurately define partial obstruction or correlate with intrapelvic pressure. The Millar solid-state transducer monitoring system is an accurate method of evaluating the intrapelvic pressure and could possibly become a standard for diagnosing significant urinary obstruction against which other studies can be evaluated.

Rapidly progressive acute renal failure due to acyclovir: case report and review of the literature.

Acyclovir nephrotoxicity has been described since the inception of the drug's use more than a decade ago. Acute renal failure mediated by this compound is characterized by abrupt elevations in serum creatinine and a gradual return to baseline renal function on discontinuation of the drug. Drug crystal formation in collecting tubules resulting in an intraparenchymal form of obstructive nephropathy has been suggested as the mechanism for acyclovir nephrotoxicity. The patient we present developed rapidly progressive acute renal failure with concomitant mental status changes in the setting of treatment with high-dose parenteral acyclovir. Acyclovir therapy was discontinued and an open renal biopsy was obtained to further evaluate our patient's diminishing renal function. Pathologic examination of the biopsy specimen revealed loss of proximal tubule brush border and dilated proximal and distal tubules with flattening of lining cells and focal nuclear loss. No crystals were noted. These changes were consistent with acute tubular necrosis with regeneration. Over the next 4 days our patient's renal and neurologic levels recovered to their prehospitalization statuses. It appears that our patient was affected by acyclovir-mediated nephrotoxicity that manifested on biopsy by acute tubular necrosis and the absence of crystalluria or crystal deposition. Intravenous acyclovir treatment can therefore produce rapidly progressive acute neurologic and renal toxicity that is usually reversible. The pathologic changes of acute tubular necrosis must now be included as part of the spectrum of renal damage associated with acyclovir therapy.