InhibiZone: Antibiotic-Impregnated Inflatable Penile Prostheses and Infection-Related Revision
InhibiZone was a retrospective cohort analysis of patient information forms voluntarily filed with the device manufacturer for 39,005 men who received a first inflatable penile prosthesis between 2001 and 2008, comparing minocycline- and rifampin-impregnated implants with nonimpregnated implants for initial revision due to infection. At up to 7.7 years, 1.1% of 35,737 men with impregnated implants and 2.5% of 3,268 men with nonimpregnated implants had undergone initial revision for infection (log-rank P < 0.0001).[1]
- Design and population
- Retrospective cohort from a voluntary manufacturer registry. Men who received a first inflatable penile prosthesis between May 1, 2001 and December 31, 2008 and had a patient information form filed with the manufacturer.
- Arms
- Minocycline- and rifampin-impregnated (InhibiZone) inflatable penile prosthesis versus nonimpregnated inflatable penile prosthesis
- Report and follow-up
- 2010 · Up to 7.7 years (life-table analysis)
| Endpoint | Results | Effect | Finding |
|---|---|---|---|
| Initial revision due to infection at up to 7.7 years | 1.1% of 35,737 vs 2.5% of 3,268 | P <0.0001 |
Voluntary manufacturer patient information form database · Report DOI
Design
The source was the manufacturer's database of patient information forms, which were filed voluntarily after implantation. The 2011 report analyzed forms for initial implants from May 1, 2001 to December 31, 2008 and compared revision for infection between impregnated and nonimpregnated devices. Device survival free of revision was estimated by life-table analysis. The authors had previously reported a lower infection rate with impregnated original implants at 1-year follow-up.[1]
InhibiZone is an antibiotic surface treatment that combines rifampin and minocycline hydrochloride.[2] The impregnated group was 35,737 men and the nonimpregnated group 3,268.[1]
Results
Initial revision due to infection was less common with impregnated implants on life-table analysis (log-rank P < 0.0001). At up to 7.7 years of follow-up, 1.1% of 35,737 men with impregnated implants and 2.5% of 3,268 men with nonimpregnated implants had undergone initial revision for infection.[1]
The manufacturer's database was analyzed in two further reports. Among diabetic men who received a first three-piece inflatable prosthesis between 2001 and 2008, initial revision for infection at any time in the study period was 1.47% of 6,071 men with impregnated implants and 4.17% of 624 with nonimpregnated implants. The life-table rate at 7 years was 1.62% versus 4.24% (log-rank P < 0.0001).[3]
At replacement surgery, in men whose first recorded operation replaced a previously implanted prosthesis (forms submitted from 2001 to 2007), secondary revision due to infection at up to 6.6 years was 2.5% of 9,300 men with impregnated implants and 3.7% of 1,764 with nonimpregnated implants (log-rank P = 0.0252).[4]
Surgery and treatment delivery
The intervention was a rifampin and minocycline hydrochloride surface treatment of the device.[2] The diabetic-men analysis included only three-piece inflatable prostheses, and the replacement analysis only men whose first recorded operation replaced an existing prosthesis.[3][4]
Adverse events
Infection-related revision was the outcome analyzed in all three reports. In the diabetes analysis, diabetic men had a higher 7-year rate of revision for infection (1.88%) than men without diabetes (1.53%; log-rank P = 0.0052).[3]
Limitations
The endpoint is surgical revision for infection, so an infection managed without a revision operation is not counted. The nonimpregnated comparison group (3,268 men) was much smaller than the impregnated group (35,737). Forms were filed voluntarily with the manufacturer, one author's listed affiliation is the manufacturer, and implants were not randomized, so patient, surgeon and perioperative differences between groups are not controlled by the log-rank comparison.[1]
In conversation
The AUA erectile dysfunction guideline summarizes a Coloplast patient-information-form analysis of the Titan prosthesis with and without its hydrophilic coating (infection 1.4% of 29,360 coated versus 4.6% of 7,031 uncoated) and a series in which 1,511 men received an infection-retardant coated device with a "no-touch" technique (infection 0.46%).[5] These reports differ in device and endpoint, and none is randomized.
Guidelines and approvals
- AUA (Erectile Dysfunction, 2018), discussion of statement 18. The guideline text cites this analysis and states that no randomized studies have compared prosthesis models with and without infection-inhibiting coatings, while observational studies indicate that coated models have greatly reduced infection rates, with most series reporting rates of 1-2%. The guideline contains no graded statement on coated devices.[5]
- FDA. The agency lists the AMS 700 inflatable penile prosthesis "with and without InhibiZone" under premarket approval N970012 (Boston Scientific).[6]
Report history
| Published | Report | Cutoff | Headline results | Citation |
|---|---|---|---|---|
| 2010-12-18 | Up to 7.7-year revision analysis · primary | — | Initial revision due to infection at up to 7.7 years: 1.1% of 35,737 vs 2.5% of 3,268; P <0.0001 | Carson CC III, Mulcahy JJ, Harsch MR. Long-term infection outcomes after original antibiotic impregnated inflatable penile prosthesis implants: up to 7.7 years of followup. *J Urol.* 2011;185(2):614-618. doi:10.1016/j.juro.2010.09.094 DOI |
| 2011-02-04 | Diabetic men, 7-year outcomes · secondary | — | Initial revision due to infection at any time during the study period: 1.47% of 6,071 vs 4.17% of 624; — Life-table rate of infection-related revision at 7 years: 1.62% vs 4.24%; P <0.0001 | Mulcahy JJ, Carson CC III. Long-term infection rates in diabetic patients implanted with antibiotic-impregnated versus nonimpregnated inflatable penile prostheses: 7-year outcomes. *Eur Urol.* 2011;60(1):167-172. doi:10.1016/j.eururo.2011.01.046 DOI |
| 2012-07-20 | Replacement implants · secondary | — | Secondary revision due to infection at up to 6.6 years: 2.5% of 9,300 vs 3.7% of 1,764; P 0.0252 | Nehra A, Carson CC III, Chapin AK, Ginkel AM. Long-term infection outcomes of 3-piece antibiotic impregnated penile prostheses used in replacement implant surgery. *J Urol.* 2012;188(3):899-903. doi:10.1016/j.juro.2012.04.116 DOI |
References
1. Carson CC III, Mulcahy JJ, Harsch MR. "Long-term infection outcomes after original antibiotic impregnated inflatable penile prosthesis implants: up to 7.7 years of followup." J Urol. 2011;185(2):614-618. doi:10.1016/j.juro.2010.09.094
2. Carson CC III. "Efficacy of antibiotic impregnation of inflatable penile prostheses in decreasing infection in original implants." J Urol. 2004;171(4):1611-1614. doi:10.1097/01.ju.0000118245.66976.e1
3. Mulcahy JJ, Carson CC III. "Long-term infection rates in diabetic patients implanted with antibiotic-impregnated versus nonimpregnated inflatable penile prostheses: 7-year outcomes." Eur Urol. 2011;60(1):167-172. doi:10.1016/j.eururo.2011.01.046
4. Nehra A, Carson CC III, Chapin AK, Ginkel AM. "Long-term infection outcomes of 3-piece antibiotic impregnated penile prostheses used in replacement implant surgery." J Urol. 2012;188(3):899-903. doi:10.1016/j.juro.2012.04.116
5. Burnett AL, Nehra A, Breau RH, et al. Erectile Dysfunction: AUA Guideline. American Urological Association; 2018. Discussion of statement 18, "Infection" (pp 29-30 of the website edition).
6. U.S. Food and Drug Administration. Premarket Approval (PMA) record N970012 S205: AMS 700 Inflatable Penile Prosthesis with and without InhibiZone. Boston Scientific Corp.