Biomedical subjects

Steven K Wilson

Publications and source records attributed to Steven K Wilson.

9 recordsLinked to original sources

PubMed2006

Current use of penile implants in erectile dysfunction.

Penile implants became popular with the introduction of effective models more than 30 years ago. Today they play a secondary but definitive role in the treatment of erectile dysfunction at times when more conservative therapies have failed. Improvements in reducing the incidence of infection, treating infection with antiseptic washes, enhancing device longevity, and instituting new techniques to manage complicated implantation procedures have made them more acceptable to patients. Although penile implants are the least often chosen and most invasive treatment for erectile dysfunction, they have the highest satisfaction rate--in the range of 80% to 90%--among both patients and partners.

Erectile Dysfunction↗

PubMed2006

Upsizing of inflatable penile implant cylinders in patients with corporal fibrosis.

INTRODUCTION: Placement of an inflatable penile prosthesis in a patient with scarred corporal bodies secondary to priapism or removal of a previously infected implant is a formidable surgical challenge; use of downsized implants has improved chances of successful reimplantation. Nevertheless, patients are frequently dissatisfied with the resulting short penises. AIM: This study investigates the use of downsized inflatable penile prosthesis cylinders as tissue expanders in patients with corporal fibrosis. MAIN OUTCOMES MEASURES: Corporal length and width were calibrated before implantation of downsized prostheses and after 1 year of their use as tissue expanders. METHODS: Thirty-seven patients had insertion of Mentor Narrow Base (18), AMS CXM (9), or AMS CXR (10) into scarred corporal bodies. Etiology was previously infected and removed implant (29) or priapism (8). In each of these cases it was not possible to dilate to 12 mm in order to place standard-sized cylinders. Patients were encouraged to inflate their implant for up to 3 hours daily. After several months intracorporal stretching occurred. The patients were reoperated; corporal length and width were recalibrated. RESULTS: Upon reoperation, it was possible to pass dilators of 12 mm width proximally allowing the substitution of standard-sized AMS 700 CX (23), Mentor Alpha 1 (10), or Mentor Titan (2). Additionally, corporal length measurements in the previously infected patients increased an average of 2.2 cm allowing placement of longer cylinders. Although priapism patients did not show this phenomenon of corporal lengthening, the implant space widened enough to permit replacement with standard-size cylinders improving girth, rigidity, and appearance. CONCLUSIONS: Wider and sometimes longer cylinders can be substituted in patients with corporal fibrosis that required implantation with downsized cylinders because of fibrotic corpora. Prolonged inflation over an 8- to 12-month period results in expansion of the cylinder cavity, permitting standard-sized cylinders in all patients.

Adult↗

PubMed2005

Revision washout decreases penile prosthesis infection in revision surgery: a multicenter study.

PURPOSE: Reoperation of penile implants carries a higher risk of infection (7% to 18%). Positive cultures and visible bacterial biofilm have been shown to be present on clinically uninfected inflatable penile prostheses (IPPs) at revision. A salvage irrigation protocol has proved to rescue patients with a clinically infected IPP. During revision surgery for noninfectious reasons we investigated washing out the implant space at revision surgery and using an antibiotic coated replacement prosthesis to determine if it would decrease subsequent infection rates. MATERIALS AND METHODS: At 3 institutions 183 patients with a penile prosthesis underwent revision surgery for noninfectious reasons between June 2001 and October 2003. Of these patients 140 had the entire implant removed and then underwent antiseptic solution lavage of the implant spaces (revision washout), followed by replacement with a 3 piece IPP. This revision washout is a modification of the original Mulcahy salvage procedure. In the remaining 43 patients the implant was removed but they did not undergo antiseptic irrigation before replacement with an antibiotic coated IPP. Patients were followed for 6 to 33 months, while observing for failure. RESULTS: Four of the 140 patients (2.86%) who underwent removal of the entire implant with irrigation of the implant spaces with antiseptic solutions and replacement with an IPP have had infection. In the remaining group 5 of the 43 patients (11.6%) who did not undergo antiseptic irrigation had infection. The difference was statistically significant at the 5% level (Fisher's exact test p = 0.034). CONCLUSIONS: Early results of combining complete implant removal and modified salvage protocol indicate a markedly decreased incidence of infection in patients with a penile prosthesis undergoing revision for noninfectious reasons.

Adult↗

PubMed2005

A survey of patients with inflatable penile prostheses for satisfaction.

PURPOSE: We assessed patient satisfaction with 3 types of penile prostheses, namely the AMS 700 Series(R), Mentor Alpha 1(R) and Mentor Alpha NB(R). MATERIALS AND METHODS: The subjects consisted of 330 patients selected by stratified, systematic random sampling from among 1,298 subjects undergoing virgin 3-piece inflatable penile implant surgeries performed by the same surgical team at 1 hospital between January 1992 and December 1998. Data were collected by computer assisted telephone interviewing with a survey developed by the authors. The survey consisted of 37 questions in 7 sections, including 1 demographic section and 6 patient satisfaction sections. RESULTS: Of the 330 patients selected 248 (75%) could be contacted. Of these, 199 (80%) responded to the full survey and the remaining 49 (20%) agreed to respond only to the question, "How satisfied are you with the prosthesis?" Of the 199 full responders 12 (6%) had AMS implants and 187 (94%) had Mentor implants. Of the 49 single question responders 5 (10%) had AMS implants and 44 (90%) had Mentor implants. Of the 248 patients the overall satisfaction rate was 69%. Although there was no significant difference at the 5% level in patient satisfaction by implant type, responses tended to favor the Alpha IPPs in terms of overall sexual satisfaction (p =0.058), natural feeling of the prosthesis (p =0.061), flaccid appearance of the penis when deflated (p =0.054), and education with demonstration of inflation and deflation (p =0.075). CONCLUSIONS: There was a high degree of overall patient satisfaction across implant types.

Humans↗

PubMed2004

Penile prosthesis cultures during revision surgery: a multicenter study.

PURPOSE: Initial implantation of inflatable penile prosthesis has a 3% risk of infection. Reoperation of penile implants has a higher rate of infection, estimated between 10% and 18%. To explain the higher risk in revision surgery in this prospective study we cultured clinically uninfected prostheses requiring revision. Prosthesis pain was also investigated as a predictor of positive culture. MATERIALS AND METHODS: At 3 institutions cultures were prospectively obtained from 77 clinically uninfected penile prostheses at revision surgery. Immediately upon surgical exposure of the pump cultures were obtained. If a bacterial biofilm was noted on any component it was additionally cultured. All culture isolates positive for a staphylococcus species were tested for sensitivity to rifampin and tetracycline (minocycline). An implant is now available that is coated with these antibiotics. Patient history of chronic prosthesis pain was ascertained. RESULTS: Culture positive bacteria were found in 54 of 77 (70%) patients with clinically uninfected penile prostheses. In some patients more than 1 organism grew and, occasionally, the pump culture was negative but the biofilm was positive. Of 54 patients 49 had positive (90%) culture for staphylococcus genus with 10 different species. All staphylococcal species were sensitive to rifampin and/or tetracycline. We did not find a significant association between prosthesis related pain and culture laboratory results. CONCLUSIONS: The majority of clinically uninfected penile prostheses have organisms growing in the implant spaces at reoperation. Most of these organisms are staphylococcal species that are sensitive to rifampin/minocycline.

Aged↗

PubMed2004

The efficacy and safety of tadalafil in United States and Puerto Rican men with erectile dysfunction.

PURPOSE: We evaluate the efficacy and safety of tadalafil, taken as needed, in men with mild to severe erectile dysfunction (ED) and assess sexual intercourse attempt patterns. MATERIALS AND METHODS: In this multicenter, double-blind, placebo controlled, parallel study conducted in the United States and Puerto Rico 207 men with ED were randomized to placebo or 20 mg tadalafil for 12 weeks. The primary efficacy variables were changes from baseline in the mean International Index of Erectile Function erectile function domain score and mean per patient percentage of "yes" responses to Sexual Encounter Profile (SEP) diary questions 2 (successful penetration) and 3 (successful intercourse). The Global Assessment Question was a secondary end point and post hoc analyses on sexual intercourse attempt patterns were conducted. RESULTS: Men treated with tadalafil compared with placebo reported greater mean changes from baseline on the erectile function domain score (9.3 vs 0.3 with placebo, p <0.001) and on the mean per patient percentage of successful penetration (SEP question 2, 31.6% vs 2.3% with placebo, p <0.001) and successful intercourse attempts (SEP question 3, 43.6% vs 3.5% with placebo, p <0.001). The per treatment group percentage of successful intercourse attempts during treatment was higher for tadalafil than placebo (67.6% vs 24.1%, respectively, p <0.001) and most successful intercourse attempts occurred between 4 and 36 hours after taking tadalafil. Of the men treated with tadalafil 82.8% reported improved erections versus 19.6% taking placebo (Global Assessment Question, p <0.001). The most common treatment emergent adverse events were headache (15.7% vs 6.3% with placebo), back pain (8.8% vs 0%), and dyspepsia (7.5% vs 0%). CONCLUSIONS: Tadalafil (20 mg) significantly improved erectile function and patients did not closely temporally link sexual intercourse attempts with taking tadalafil. Tadalafil was also well tolerated in both groups of men with mild to severe ED.

3',5'-Cyclic-GMP Phosphodiesterases↗

PubMed2003

New surgical technique for sphincter urinary control system using upper transverse scrotal incision.

PURPOSE: Traditional implantation of the AMS Sphincter 800 Urinary Control System (American Medical Systems, Minnetonka, Minnesota) requires 2 incisions. The cuff is placed via a perineal incision, and the pressure regulating balloon and pump are placed through a separate suprapubic incision. We describe a novel implantation of all the artificial urinary sphincter components using a single upper scrotal incision. The scrotal incision allows excellent access to the proximal bulbar urethra and retropubic and subdartos spaces, and leaves the bulbocavernosus muscle intact. MATERIALS AND METHODS: A total of 37 patients have undergone artificial urinary sphincter implantation using the new operative technique for revisions or reimplantations of a sphincter previously removed for infection/erosion (12) or as an initial procedure (25). In 9 of the 25 patients and 2 of the 12 dual implantation of a 3-piece penile prosthesis through the same incision was performed. RESULTS: All patients are using the devices. Of the patients 66% are completely dry with no pad use and the remainder use 1 pad for accident prevention. Operative time was reduced due to easier exposure of the urethra and a second incision for placement of the pressure regulating balloon was not necessary. Followup at 1 year shows no difference in complication rate with the single incision technique compared to the traditional method. CONCLUSIONS: Artificial urinary sphincter implantation through a single scrotal incision is easier and faster than the traditional 2-incision technique. Success in achieving continence is similar to traditional methods. Long-term followup is necessary to ensure that complications remain low.

Humans↗

PubMed2003

Reimplantation of inflatable penile prosthesis into scarred corporeal bodies.

Reimplantation of an inflatable three-piece prosthesis in a patient with severe corporeal fibrosis represents a formidable surgical challenge. In the past, a variety of techniques have been offered to facilitate implantation in these difficult patients including the use of instruments to produce a channel in which cylinders can be placed and choosing multiple surgical sites, including the use of surgical sites that have not previously been used. The author of this communication describes newer tools and techniques to enhance placement of an inflatable device in patients with severe fibrosis. This includes the use of specially designed cavernotomes for dilating fibrotic corpora, the use of downsized prosthetic cylinders, alternative procedures to fix cylinders in the face of perforation as opposed to primary closure of the perforation, and replacing the original cylinders after 1 y after the modified cylinders have served as tissue expanders. Details of these newer techniques are presented by an experienced surgeon.

Cicatrix↗

PubMed2002

The mentor Alpha 1 penile prosthesis with reservoir lock-out valve: effective prevention of auto-inflation with improved capability for ectopic reservoir placement.

PURPOSE: Auto-inflation is a common and annoying complication of 3-piece penile prostheses. In the published literature the rate is approximately 11% with a 2% operative revision rate. We report the results of a review of 160 Alpha 1 and NB implants (Mentor Corp., Santa Barbara, California) with the new lock-out valve located on the reservoir to treat impotence. We compared it with 339 Alpha 1 implants with the standard reservoir. We also investigated the lock-out reservoir for ectopic nonretropubic implantation. MATERIALS AND METHODS: We compared 339 Alpha prostheses with the standard reservoir that were implanted between January 1, 1998 through December 31, 1999 and 160 with the new lock-out valve placed since January 2000 with at least 6 months of followup. Implants were further stratified as first time (virgin) or revision-replacement of a previous implant. In 8 patients with a scarred or obliterated retroperitoneal space the lock-out reservoir was placed superior to the transversalis fascia and beneath the abdominal musculature. RESULTS: Kaplan-Meier estimated 1-year survival was not significantly different in terms of mechanical failure (p = 0.57 and 0.85) revision for any cause (p = 0.92 and 0.92), patient dissatisfaction (p = 0.35 and 0.11) or infection (p = 0.64 and 0.94) for all implants and virgin implants only, respectively. Only 2 patients (1.3%) with a lock-out valve complained of auto-inflation initially and the problem resolved in each after instruction on how to operate the device. Of the patients in the earlier series 11% complained of auto-inflation and 2% required operative correction. None of the 8 patients with an ectopic reservoir location complained of auto-inflation. CONCLUSIONS: Our results indicate that the lock-out valve prevents early auto-inflation. Addition of the lock-out valve does not impact the revision rate compared with the same implant with a standard reservoir. In patients with a scarred retropubic space the lock-out valve offers the penile implant surgeon a decreased probability of auto-inflation with ectopic reservoir placement.

Cohort Studies↗