MECHANICAL COMPLICATIONS ASSOCIATED WITH MENTOR INFLATABLE PENILE PROSTHESIS WILLIAM B. STEINKOHL, M.D. GARY E. LEACH, M.D.
From the Department of Urology, Kaiser Permanente Medical Center, Los Angeles, California ABSTRACT--The Mentor inflatable penile prosthesis was developed in an attempt to decrease the mechanical failure rate of the various prostheses" components. We herein report on the reliability oJ the device in 46 men implanted with the Mentor device from December 1982 to June 1987. Prior to manufacturer device modification in 1985, mechanical failure mainly attributable to input tubing cracks occurred in 10 of 30 implantations. Since device improvement in April 1985, the mechanical failure rate has decreased to 4 percent. The Mentor inflatable penile prosthesis has been a mechanically reliable device since design improvement in 1985.
The inflatable penile prosthesis has provided an attractive alternative to rigid prostheses in the treatment of the impotent male. Inflatable prostheses have the advantage of enhanced concealment, excellent flaeeidity~ and superior girth and rigidity when erect. However, the major drawback of the inflatable devices has been the high rate of mechanical complications requiring reoperation. The Mentor inflatable penile prosthesis (IPP) was developed in an attempt to decrease the risk of device failure due to mechanical problems. We herein report our experience with regard to device reliability in 46 men implanted with the Mentor IPP. Material and Methods The charts of 46 men who underwent implantation of a Mentor IPP from December 1982 to June 1987 were reviewed. The patients ranged in age from thirty-fve to seventy-five years, with a mean age of 58.5 years. All men underwent a complete history and physical examination, determination of serum testosterone and prolaetin (except in those patients who had undergone prior implantation), and psychologic evaluation prior to surgery. Nocturnal penile tumescence evaluation and determina-
32
TABL~ I. Etiology of impotence (N = 46) Etiology No. of Pts. Diabetes mellitus 14 Vaseulogenie 13 Radical pelvic surgery 8 Neurologic 5 Endocrine 3 Peyronie's disease 2 Psychogenic 1
tion of penile brachial indices were performed when appropriate. Forty-five of the men had an organic etiology for their erectile dysfunction, the most commo~ causes being diabetes mellitus and hypertensio~ (Table I). Seventeen percent of the group were impotent secondary to radical pelvic cancer surgery. Eight men were converted to a Mentor IPP after a previous prosthesis was removed (Table II). The duration of erectile dysfunctio0 prior to implantation ranged from eight month~ to twenty years (mean 5.5 years), la1 I m p l a n t a t i o n was p e r f o r m e d t h r o u g penoserotal approach early in the series and!i through a transserotal approach since 1985.! The patients were instructed to refrain fror0 UROLOGY
/ JULY 1991 /
VOLUME XXXVIII, NUMBER1
Patients with prior implantation ( N = 8)
!th Prior Implant dlure of previous ~rosthesis ervoir into bladder emirigid prosthesis isfaetion with evice
No. of Pts. 4 1 2 1
[II. lnitial mechanical failure tor inflatable prosthesis (IV = 10) nterval Failure Mechanical Failure 1 mo. Pump failure 31 mo. Cylinder input tube crack 36 mo. Cylinder input tube crack /2 mo. Cylinder input tube crack 38 mo. Pump tube crack L2 mo. Cylinder input tube crack 1 mo. Tube kink L9 mo. Tube kink !4 mo. Cylinder input tube crack 4 mo. Pump failure
Patients requiring second revision ( N = 3)
)uration to !nd Failure
Mechanical Failure Pump tube crack Cylinder input tube crack Cylinder input tube crack
7 mo.
1 mo. 21 mo.
until they were pain-free (usually 4 Results 2 % of the study group) expe9des of mechanical device failure cal revision (Table III). Three Of :quired a second surgical revision uent mechanical problem (Table h of time from implantation to ion averaged sixteen months )nths). Only 1 of the 10 patients a previous implant. Findings at ~vision included cylinder input ',ing fluid loss in 7, pump tubing
•0LOGY ~;
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JULY 1991
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VOLUME XXXVIII, NUMBER 1
FtCURE 1. Typical location of input tubing crack adjacent to prosthesis cylinder. crack in 2, t u b i n g kink in 2, and p u m p malfunction in 2 (Fig. 1). In response to the development of input tubing cracks, Mentor reinforced the junction of the input tube and the cylinder (and introduced "kink-free" tubing) in April 1985. Before this date, tubing-related failure occurred in 33 percent (10 of 30 men). After April 1985, only 1 in 25 men (4 %) experienced fluid loss due to a tubing crack. Comment The development of the inflatable penile prosthesis by Scott et al. 2 heralded a new era in the treatment of erectile dysfunction. However, enthusiasm for the inflatable penile prosthesis has been tempered by a significant mechanical failure rate. 3-s Silicone cylinders employed in the early IPP experience frequently resulted in cylinder aneurysms and cylinder rupture. Suture-tied connections also were associated with leaks from the connection points. Kesslera reported a 16 percent failure rate in 128 patients implanted with the American Medical Systems IPP between 1974 and 1979. The most common problem reported was fluid loss, but the exact component which was defective was not specified. Joseph, Bruskewitz, and Benson7 reviewed 88 patients with implants between 1977 and 1982. Fifty percent of the patients required at least one revision with the cylinders and tubing being most susceptible to failure. The Mentor IPP was developed in an attempt to improve the reliability of inflatable penile prostheses, s'9 Cylinders were constructed using polyurethane to alleviate the problem of cylinder aneurysms and cylinder rupture. Snap-on
33
connectors were utilized to more reliably secure connection points and to avoid failure at the connection sites. Complications with the Mentor IPP have been minimal in a number of series. Hackler s reported no complications in 46 men implanted with the Mentor IPP with an average follow-up of twenty-one months. Merrill's 1° extensive review of 206 patients also attested to the reliability of the Mentor IPP. The overall mechanical failure rate was 7.3 percent with an average follow-up of 18.1 months. Tubing leaks were the most common problem (2.9%), although the site of damage was not specified. The series herein reported had an overall mechanical failure rate higher than other series (22 % of 46 patients). The most common problem was input tubing crack adjacent to the cylinder. In response to this problem, the manufacturer reinforced the junction between the cylinder and the input tubing as well as introducing kink-free tubing in April 1985. Since that time, there has been only one failure with the improved components. Prior to kink-free tubing and input tubing reinforcement at the eylinder junetion, there were 10 complications secondary to tubing failures in 30 implantations (33%) with an average follow-up of thirty months. Sinee these modifications were made, there has been only one failure in 25 implantations (4 %) with follow-up of eighteen months. Due to the significant problems herein reported associated with the "premodifieation" Mentor IPP components, should re-exploration of the Mentor IPP be necessary, cylinders
34
without reinforced input tubing as well as the i{ older pump design without "kink-free tubing ii should be replaced regardless of the surgical findings. The Mentor IPP was developed to minimize cylinder and connector problems, and the current series supports the success of the device (especially since device modification in April 1985). There have been no connector failures or true cylinder failure due to aneurysmal dilatation or cylinder rupture. The most significant problem in this series was input cracks w h i c h have been minimized by device modification. Los Angeles, California 90027 (DR. LEACH) References 1. Leach GE: Trans-scrotal insertion of the inflatable penile prosthesis, Urology 27:465 (1986). 2. Scott FB, Bradley WE, and Timm GW: Management of erectile impotence: use of implantable inflatable prostheses, Urology 2:80 (1973). 3. Kessler R: Complications of inflatable penile prostheses, Urology 18:470 (1981). 4. Kaufman JJ, Lindner A, and Raz S: Complications of penile prosthesis surgery for impotence, J Urol 128:1192 (1982),! 5. Merrill DC: Clinical experience with the Scott inflatable! penile prosthesis in 150 patients, Urology 22:372 (1983). 6. Brooks MB: Forty-two months of experience with Mentor! inflatable prosthesis, J Urol 139:48 (1988). 7. Joseph DB, Bruskewitz RC, and Beuson RC Jr: Long-termi evaluation of inflatable penile prosthesis, J Urol 131: 670i~ (1984). 8. Hackler RH: Mentor inflatable penile prosthesis: a reliabl( mechanical device, Urology 28:489 (1986). 9. Merrill DC: Mentor inflatable penile prosthesis, Urology 221 504 (1983). 10. Merrill DC: Clinical experience with Mentor inflatabl~ penile prosthesis in 206 patients, Urology 28:185 (1986).
UROLOGY
/ JULY 1991 /
VOLUME XXXVIII, NUMBEBi
From the Department of Urology, Kaiser Permanente Medical Center, Los Angeles, California ABSTRACT--The Mentor inflatable penile prosthesis was developed in an attempt to decrease the mechanical failure rate of the various prostheses" components. We herein report on the reliability oJ the device in 46 men implanted with the Mentor device from December 1982 to June 1987. Prior to manufacturer device modification in 1985, mechanical failure mainly attributable to input tubing cracks occurred in 10 of 30 implantations. Since device improvement in April 1985, the mechanical failure rate has decreased to 4 percent. The Mentor inflatable penile prosthesis has been a mechanically reliable device since design improvement in 1985.
The inflatable penile prosthesis has provided an attractive alternative to rigid prostheses in the treatment of the impotent male. Inflatable prostheses have the advantage of enhanced concealment, excellent flaeeidity~ and superior girth and rigidity when erect. However, the major drawback of the inflatable devices has been the high rate of mechanical complications requiring reoperation. The Mentor inflatable penile prosthesis (IPP) was developed in an attempt to decrease the risk of device failure due to mechanical problems. We herein report our experience with regard to device reliability in 46 men implanted with the Mentor IPP. Material and Methods The charts of 46 men who underwent implantation of a Mentor IPP from December 1982 to June 1987 were reviewed. The patients ranged in age from thirty-fve to seventy-five years, with a mean age of 58.5 years. All men underwent a complete history and physical examination, determination of serum testosterone and prolaetin (except in those patients who had undergone prior implantation), and psychologic evaluation prior to surgery. Nocturnal penile tumescence evaluation and determina-
32
TABL~ I. Etiology of impotence (N = 46) Etiology No. of Pts. Diabetes mellitus 14 Vaseulogenie 13 Radical pelvic surgery 8 Neurologic 5 Endocrine 3 Peyronie's disease 2 Psychogenic 1
tion of penile brachial indices were performed when appropriate. Forty-five of the men had an organic etiology for their erectile dysfunction, the most commo~ causes being diabetes mellitus and hypertensio~ (Table I). Seventeen percent of the group were impotent secondary to radical pelvic cancer surgery. Eight men were converted to a Mentor IPP after a previous prosthesis was removed (Table II). The duration of erectile dysfunctio0 prior to implantation ranged from eight month~ to twenty years (mean 5.5 years), la1 I m p l a n t a t i o n was p e r f o r m e d t h r o u g penoserotal approach early in the series and!i through a transserotal approach since 1985.! The patients were instructed to refrain fror0 UROLOGY
/ JULY 1991 /
VOLUME XXXVIII, NUMBER1
Patients with prior implantation ( N = 8)
!th Prior Implant dlure of previous ~rosthesis ervoir into bladder emirigid prosthesis isfaetion with evice
No. of Pts. 4 1 2 1
[II. lnitial mechanical failure tor inflatable prosthesis (IV = 10) nterval Failure Mechanical Failure 1 mo. Pump failure 31 mo. Cylinder input tube crack 36 mo. Cylinder input tube crack /2 mo. Cylinder input tube crack 38 mo. Pump tube crack L2 mo. Cylinder input tube crack 1 mo. Tube kink L9 mo. Tube kink !4 mo. Cylinder input tube crack 4 mo. Pump failure
Patients requiring second revision ( N = 3)
)uration to !nd Failure
Mechanical Failure Pump tube crack Cylinder input tube crack Cylinder input tube crack
7 mo.
1 mo. 21 mo.
until they were pain-free (usually 4 Results 2 % of the study group) expe9des of mechanical device failure cal revision (Table III). Three Of :quired a second surgical revision uent mechanical problem (Table h of time from implantation to ion averaged sixteen months )nths). Only 1 of the 10 patients a previous implant. Findings at ~vision included cylinder input ',ing fluid loss in 7, pump tubing
•0LOGY ~;
/
JULY 1991
/
VOLUME XXXVIII, NUMBER 1
FtCURE 1. Typical location of input tubing crack adjacent to prosthesis cylinder. crack in 2, t u b i n g kink in 2, and p u m p malfunction in 2 (Fig. 1). In response to the development of input tubing cracks, Mentor reinforced the junction of the input tube and the cylinder (and introduced "kink-free" tubing) in April 1985. Before this date, tubing-related failure occurred in 33 percent (10 of 30 men). After April 1985, only 1 in 25 men (4 %) experienced fluid loss due to a tubing crack. Comment The development of the inflatable penile prosthesis by Scott et al. 2 heralded a new era in the treatment of erectile dysfunction. However, enthusiasm for the inflatable penile prosthesis has been tempered by a significant mechanical failure rate. 3-s Silicone cylinders employed in the early IPP experience frequently resulted in cylinder aneurysms and cylinder rupture. Suture-tied connections also were associated with leaks from the connection points. Kesslera reported a 16 percent failure rate in 128 patients implanted with the American Medical Systems IPP between 1974 and 1979. The most common problem reported was fluid loss, but the exact component which was defective was not specified. Joseph, Bruskewitz, and Benson7 reviewed 88 patients with implants between 1977 and 1982. Fifty percent of the patients required at least one revision with the cylinders and tubing being most susceptible to failure. The Mentor IPP was developed in an attempt to improve the reliability of inflatable penile prostheses, s'9 Cylinders were constructed using polyurethane to alleviate the problem of cylinder aneurysms and cylinder rupture. Snap-on
33
connectors were utilized to more reliably secure connection points and to avoid failure at the connection sites. Complications with the Mentor IPP have been minimal in a number of series. Hackler s reported no complications in 46 men implanted with the Mentor IPP with an average follow-up of twenty-one months. Merrill's 1° extensive review of 206 patients also attested to the reliability of the Mentor IPP. The overall mechanical failure rate was 7.3 percent with an average follow-up of 18.1 months. Tubing leaks were the most common problem (2.9%), although the site of damage was not specified. The series herein reported had an overall mechanical failure rate higher than other series (22 % of 46 patients). The most common problem was input tubing crack adjacent to the cylinder. In response to this problem, the manufacturer reinforced the junction between the cylinder and the input tubing as well as introducing kink-free tubing in April 1985. Since that time, there has been only one failure with the improved components. Prior to kink-free tubing and input tubing reinforcement at the eylinder junetion, there were 10 complications secondary to tubing failures in 30 implantations (33%) with an average follow-up of thirty months. Sinee these modifications were made, there has been only one failure in 25 implantations (4 %) with follow-up of eighteen months. Due to the significant problems herein reported associated with the "premodifieation" Mentor IPP components, should re-exploration of the Mentor IPP be necessary, cylinders
34
without reinforced input tubing as well as the i{ older pump design without "kink-free tubing ii should be replaced regardless of the surgical findings. The Mentor IPP was developed to minimize cylinder and connector problems, and the current series supports the success of the device (especially since device modification in April 1985). There have been no connector failures or true cylinder failure due to aneurysmal dilatation or cylinder rupture. The most significant problem in this series was input cracks w h i c h have been minimized by device modification. Los Angeles, California 90027 (DR. LEACH) References 1. Leach GE: Trans-scrotal insertion of the inflatable penile prosthesis, Urology 27:465 (1986). 2. Scott FB, Bradley WE, and Timm GW: Management of erectile impotence: use of implantable inflatable prostheses, Urology 2:80 (1973). 3. Kessler R: Complications of inflatable penile prostheses, Urology 18:470 (1981). 4. Kaufman JJ, Lindner A, and Raz S: Complications of penile prosthesis surgery for impotence, J Urol 128:1192 (1982),! 5. Merrill DC: Clinical experience with the Scott inflatable! penile prosthesis in 150 patients, Urology 22:372 (1983). 6. Brooks MB: Forty-two months of experience with Mentor! inflatable prosthesis, J Urol 139:48 (1988). 7. Joseph DB, Bruskewitz RC, and Beuson RC Jr: Long-termi evaluation of inflatable penile prosthesis, J Urol 131: 670i~ (1984). 8. Hackler RH: Mentor inflatable penile prosthesis: a reliabl( mechanical device, Urology 28:489 (1986). 9. Merrill DC: Mentor inflatable penile prosthesis, Urology 221 504 (1983). 10. Merrill DC: Clinical experience with Mentor inflatabl~ penile prosthesis in 206 patients, Urology 28:185 (1986).
UROLOGY
/ JULY 1991 /
VOLUME XXXVIII, NUMBEBi
