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Corporeal Veno-Occlusive Dysfunction: Predominantly Intracavernous Muscular Pathology
~-5347/97/1575-1678$03.00/0
Vol. 157. 1678-1680,May 1997 Printed i n U.S.A
THE JOURNAL OF UROIBGY Copyright 0 1997 by AMERICAN UR0LXX;ICAL
~ C ~ A T I O INC. N .
CORPOREAL WNO-OCCLUSIVE DYSFUNCTION: PREDOMINANTLY INTRACAWRNOUS MUSCULAR PATHOLOGY ERIC WESPES, AHMED A. SATTAR, JAFAR GOLZARIAN, DIDIER WERY, NICOLAS DAOUD CLAUDE C. SCHULMAN From the Departments
of
AND
Urology, Radiology, and Haematology and Microbiology, Erasme Hospital, Brussels, Belgium
ABSTRACT
Purpose: We investigated whether a relationship exists between the flow to maintain a n erection obtained at cavernosometry and the alteration of intracavernous structures in impotent patients with corporeal veno-occlusive dysfunction and normal arterial inflow. Materials and Methods: Computerized histomorphometric analysis of smooth muscle and elastic fibers, and endothelial cells was compared to the flow necessary to maintain erection after intracavernous vasoactive drug injection in 18 patients with corporeal veno-occlusive dysfunction. Results: A significant correlation between percentage of smooth muscle fibers a n d flow to maintain erection was observed, while no correlation was noted with elastic fibers and endothelial cells. Conclusions: Corporeal veno-occlusive dysfunction seems to be due mainly to smooth muscular alterations. According to this observation treatment of impotent patients with this abnormality should not be restricted to the penile veins but should also include the intracavernous structures, predominantly the muscular component. Key
WORDS:impotence, venous insufficiency, histology, penile erection
Erection is a vascular phenomenon under neurological control modulated by a specific hormonal environment and occurring in a particular psychological context.' During tumescence the intracavemous smooth muscles are relaxed, producing arterial dilatation and filling of the lacunar spaces. Compression of the sub-albugineal venous plexus by the lacunar spaces against the tunica albuginea increases the resistance to flow through the emissary veins, which induces penile rigidity.2.3 Failure to trap arterial blood in the penis is a frequent abnormality in impotence, and it currently is the most challenging problem in the diagnosis and treatment of erectile dysfunction. Alteration of the intracavernous smooth muscles4-7 or in the fibroelastic components of the trabecula6 seems to be the underlying cause of this syndrome, which explains the failures observed with surgical treatment restricted to the penile veins.$ However, no modification of the percentage of endothelial cells was observed.10 To understand better and determine the best treatment for this condition we compared the percentage of the different intracavemous structures obtained by histomorphometric study (smooth muscle and elastic fibers, and endothelial cells) to the flow necessary to maintain erection at cavernosometry. MATERIAL A N D METHODS
Clinical investigations. A total of 18 men 39 to 73 years old (mean age 52) was diagnosed with pure venous leakage based on a detailed sexual history and physical examination. Full blood and hormonal assays were done to exclude endocrinological disease. Every patient spent a t least 1 night at the hospital to evaluate the nocturnal tumescence with the Rigiscan* device. Nocturnal penile tumescence was interpreted based on multiple parameters, including duration of recording longer than 5 hours a night, frequency of tumescence 1to 2 a night, duration of erection 10 minutes or longer, Accepted for publication September 27, 1996. * Dacomed. Minneapolis, Minnesota.
increase in penile tip and base length by 2.5 cm. or greater and penile rigidity 60%or greater at the tip and base. Duplex ultrasound (7.5 MHz. device) was used to obtain real-time images of the corpora cavernosa, and for visualization and Doppler calculations of the blood flow in the cavernous arteries. With the patient in the supine position the duplex probe was placed on the ventral side at the base of the penis, and a baseline image of the penis was obtained in the longitudinal and transverse planes, including measurements of blood flow in the cavernous arteries. A 20 pg. dose of prostaglandin E l was injected intracavernously using a 27% gauge needle. Blood flow in the cavernous arteries was measured a t approximately 2,5,10 and 20 minutes after injection, and peak and end diastolic velocities were determined. Peak systolic velocity greater than 35 cm. per second and end diastolic velocity less than 5 cm. per second demonstrated normal penile arterial inflow. Pharmacocavernosometry and pharmacocavernosography were performed with the patient supine on a n angiography table. A 19 gauge needle was inserted dorsolaterally in the right corpus cavernosum approximately halfway down the shaft and 20 pg. prostaglandin E l were injected. At 10 minutes after intracavernous injection body temperature physiological saline solution was injected through the needle with a high flow mechanical pump, with flow rates starting at 40 ml. per minute and increasing incrementally by 40 ml. per minute every minute until a full rigid erection was achieved. Rigid erection, evaluated subjectively by digital palpation, was sufficient for easy vaginal penetration. The flow rates needed to induce and maintain erection were recorded. A flow rate to maintain erection equivalent t o or greater than 15 ml. per minute was considered abnormal. Cavernosography was performed with injection of a low osmolality contrast medium diluted 1:4 with 2.500 p.A. heparinized saline solution to avoid a n y risk of thrombosis of the cavernous bodies. Serial films \yere t a k e n with a 100 mm. camera, and the corpora C ~ V W I I I I S ~a n d penile v e n o ~ i snetwork were studied i n thcx ohlicluc. ;md a n t c i . o p o s t ~ i i o projecr
1678
CORPOREAL -NO-OCCLUSIVE
tions At the end of the procedure the corpora were emptied by dixonnecting the needle to clear the contrast material. A sterile compression dressing was applied to prevent formation of a hematoma and stasis of the contrast medium. A pediatric cuff was inflated for 10 to 15 minutes to ensure effective compression. Tzssue processing. During vascular reconstruction or penile implantation a penile biopsy was obtained, the corpora were surgically opened and a small specimen under the tunica albuginea was resected. Light microscope evaluation and immunohistochemical staining were done. Following surgical removal cavernous biopsy specimens were immediately fixed in 10% formalin phosphate buffer solution, processed through xylene, embedded in paraffin and sectioned a t 5 pm. intervals. Four serial tissue sections were then used for hematoxylin and eosin staining and light microscopy to evaluate the cavernous tissue pathologically (11,for immunohistochemistry staining using factor VIII to determine the endothelial cells and actin anti-actin for smooth muscle fibers ( 2 ) , and for orcein staining for the elastic fibers (1).Immunohistochemical staining was used according to the biotinstreptavidin-peroxidase technique. The sections were incubated for 15 minutes with 2% (volume-in-volume)hydrogen peroxide solution to block endogenous peroxidase activity and processed for immunohistochemistry. After incubation with 1to 20 normal sheep serum, the sections were incubated overnight (14to 18 hours) with mouse anti-human factor VIII antibodies diluted 150 or with mouse anti-human antiactin antibodies diluted 1:50.After rinsing, the sections were incubated for 30 minutes at room temperature successively with sheep anti-mouse immunoglobulin biotin diluted 1:500 and with streptavidin, which is coupled to peroxidase 1:1,000 for 30 minutes. Peroxidase activity was revealed by 10 mg./lO ml. 3.3-diamin~henzidine~ pH 7.4, containing 0.01% (volumein-volume) hydrogen peroxide for 5 to 10 minutes at room temperature. Computerized image analysis. Quantitative analysis of endothelial cells, smooth muscle or elastic fibers in cavernous tissue was done with an image analyzer system combined with a light microscope equipped with a video camera. The images were interactively discriminated and the measurements were performed on the resulting binary images. The percentage of the structures for each image results from the quantification of the difference between the gray levels in the digitalized image. At least 20 different fields (X400)in the cavernous tissue were examined from each tissue section. The mean percentage was then considered.
1679
DYSFUNCTION
Cavernosomtry pammeter versus flow to maintain erection, and the percentage of cavermus smooth muscle fibers. elastic fibers and endothelial cells
kyz)
Flow Maintain pt'Age
60 52 56 73 35 50 51 58 70 44 39 70 47 53 44 50 43 39 Mean 51.88
100 50
40 40 20 40 20 25 20 15 50 80 40 80 50 80 80
40 48.33
% Smooth % Elastic % Endothelid Musclefibers Fibers Cells
19 21 19.6 22 32 27.7 28.3 26 30.7 33.2 21.4 22.4 24.6 19 27.2 22 23 26.4 24.75
5.5 6.3 5.4 4.7 6.2 5 5.3 4 3.3 4.4 3.9 4.7 6.2 5.3 4.2 6.7 3.8 4.2 4.95
2.7 2.2 1.4 4.6 3.3 1.8 2.2 3.9 2.6 2.5 3.5 2.4 3.8 1.6 4.3 3.4 2.6 2.8 2.86
of the trabecular smooth muscle, the basic structure in the mechanism of erection.1.2 Sufficient elasticity and compliance of the cavernous trabeculae are required for penile elongation. The intact lacunar space endothelial cells release endothelium-derived relaxing factor, which is diffused to the underlying smooth muscle causing its relaxation.12 This relaxation allows for expansion of the lacunar spaces and subsequent trapping of blood within the corpora due to compression of the subtunical venules by the dilated lacunar space^.^ Impotent patients may have adequate arterialinflow to the penis but excessive outflow through the cavernous subtunical venules. In these patients the corporeal veno-occlusive mechanism may not be functional, as diagnosed by pharmacoeavernosometry and cavernosography.13-14 These techniques have a major role in evaluating the degree of corporeal venous outflow resistance and demonstrating the routes of venous leak for planning of possible veno-ablative therapy. Indeed, these techniques should always be performed after smooth muscle relaxation by intracavernous vasoactive agent injection to obtain analogues to the physiological situation. During cavernosometry venous outflow resistance is assessed by determining the intracavemous flow rate of saline required to create or sustain an erection,l2.13 or by infusing saline to a suprasystolic intracavernous pressure and determining the rate of the pressure decrease after the infusion is RESULTS stopped.16 We relied predominantly on determination of the All patients had abnormal nocturnal tumescence, mainly infusion to maintain the erection and we standardized our characterized by short durations of tumescence and rigidity value as less than 15 ml.per minute. This maintenance flow greater than 60% a t the tip and base. They all had a normal rate used as the normal parameter was similar to that sugpeak systolic velocity of greater than 35 cm. per second but gested by others.16-18 a peak diastolic velocity of greater than 5 cm. per second. When flow to maintain the erection was compared to the Cavernosometry ranged from 15 to 100 ml. per minute percentage of cavernous smooth muscle fibers a relatively (mean 48.33, see table). The smooth muscle cell component good inversely proportional correlation was observed. The ranged from 19 to 28.3% (mean 24.75,normal plus or minus greater the percentage of cavernous smooth muscle, the standard deviation 45.2 5 3.2),8elastic fibers from 3.2 to lower the flow rate to maintain erection (part A of figure). 6.7% (mean 4.95,normal 9 2 2.5)" and endothelial cells from The other key factor in normal corporeal veno-occlusive 1.4to 4.6% (mean 2.86,normal 2.8 2 lU.10 dysfunction is the compliance of the trabecular fibmlastic A significant correlation was observed between the flow to frame. Its contribution is fixed and does not depend on the maintain erection and smooth muscle fibers (R2= 0.5777), degree of relaxation or contraction of the smooth muscle while no correlation was noted with the elastic fibers (R2= fibers but on intrinsic structural characteristics. A decrease 0.0402) and/or endothelial cells (R2= 0.0165,see figure). in elastic fibers has already been demonstrated in patients with veno-occlusive dysfunction8~but in our study no correDISCUSSION lation was observed between this decrease and the flow necThe intracavernous structures (cavernous smooth muscle essary to maintain the erection (part B of figure). This obserfibers, elastic fibers and endothelial cells) cooperate together vation demonstrated that elastic fibers may have a role in the with the penile vascular system to control the processes of physiopathological mechanism but this is certainly not of erection and flaccidity.'. 2 During erection there is relaxation crucial value as the role of the smooth musculature.
1680
CORPOREAL VENO-OCCLUSIVE DYSFUNCTION
I
I
I
. .
E
q'
I -
9'
i I: Ud--d
%d-dux6b
Xd--lr*h
B
A
C
Percent cavernous smooth muscle fiber(A), percent cavernous elastic fibers ( B )and percent cavernous endothelial cells correlated with flow to maintain erection.
Also, no correlation was noted between the endothelial cells and the flow to maintain erection (part C of figure). However, this observation did not exclude functional alteration of the endothelium and further investigations are required.I2 Indeed, these correlations could explain the importance of the percent of cavernous smooth muscle fibers in the diagnosis of the degree of caverno-venous leak, which could be an important factor that influences the surgical results. Most reports of surgery for venogenic impotence showed actual positive results of this surgery of less than 50%.IaPreviously, it was reported that impotent patients who underwent surgery due to caverno-venous dysfunction had good results when cavernous smooth muscle fibers were greater than 29%19or when good electromyography of the cavernous muscles was recorded.20 To study the intracavernous structures a small biopsy can be performed when vascular reconstruction is indicated.2' Morphometric analysis has already demonstrated no difference in the percentage of smooth muscle fibers in the different areas of the penis, meaning that vascular impotence is a diffuse disease.22 CONCLUSIONS
The question raised is what factor can influence the integrity of cavernous smooth muscle fibers and, consequently, the diagnosis of caverno-venous dysfunction. This phenomenon of caverno-venous dysfunction may be due to vascular injury although the cavernous arteries are normal when studied with Doppler ultrasound. The helicine arteries are not investigated with this technique and could be abnormal, which results in the formation of a state of ischemia and, consequently, fibrosis of the cavernous smooth muscle fibers.23 Further studies are needed to explain the observation of low cavernous oxygen tension in this phenomenon and its relationship to cavernous smooth muscle alteration. Venoocclusive dysfunction could be the first event in the pathophysiological process of arterial disease. It is possible that presently lack of a more sensitive method of evaluation of penile arterial flow might explain these findings. REFERENCES
1. Krane, R. J., Goldstein, I. and Saenz de Tejada, I.: Impotence. New Engl. J. Med., 321: 1648, 1989. 2. Lue,T. F. and Tanagho, E. A.: Physiology of erection and pharmacological management of impotence. J. Urol., 137: 829, 1987. 3. Fournier. G.R., Jr., Juenemann, K-P., Lue, T. F. and Tanagho, E. A: Mechanism of venous occlusion during canine penile erection: an anatomic demonstration. J. Urol., 137 163,1987. 4. Persson, C., Diederichs, W.. Lue, T. F., Yen, T. S. B., Fishman, I. J., McLin, P. H. and Tanagho, E. A.: Correlation of altered penile ultrastructure with clinical arterial evaluation. J. Urol., 142 1462.1989. 5. Jevtich, M. J., Khawand, N. Y. and Vidic, B.: Clinical signifi-
cance of ultrastructural findings in the corpora cavernosa of normal and impotent men. J. Urol., 143: 289,1990. 6. Mersdorf, A., Goldsmith, P. C., Diederichs, W.,Padula, C. A., Lue, T. F., Fishman, I. J. and Tanagho, E.A.: Ultrastructural changes in impotent penile tissue: a comparison of 65 patients. J. Urol., 145: 749,1991. 7. Wespes, E., Goes, P. M., Schiffmann, S., Depierreux, M., Vanderhaeghen, J.J. and Schulman, C. C.: Computerized analysis of smooth muscle fibers in potent and impotent patients. J. Urol., 1 4 6 1015,1991. 8. Sattar, A. A., Wespes, E. and Schulman, C. C.: Computerized measurement of penile elastic fibres in potent and impotent men. Eur. Urol., 25: 142, 1994. 9. Wespes, E. and Schulman, C. C.: Venous impotence: pathophysiology, diagnosis and treatment. J. Urol., 149 1238,1993. 10. Sattar, A. A.,Schulman, C. C. and Wespes, E.: Objective quantification of cavernous endothelium in potent and impotent men. J. Urol., 1 5 3 1136,1995. 11. Sattar, A. A,, Haot, J., Schulman, C. C. and Wespes, E.: Comparison of anti-desmin and anti-actin staining for the computerized analysis of cavernous smooth muscle density. Brit. J. Urol., 77: 266,1996. 12. Saenz de Tejada, I., Goldstein, I., Azadzoi, K., Krane, R. J. and Cohen, R. A.: Impaired neurogenic and endothelium-mediated relaxation of penile smooth muscle from diabetic men with impotence. New Engl. J. Med., 3 2 0 1025,1989. 13. Wespes, E., Delcour, C., Struyven, J. and Schulman, C. C.: Pharmacocavernometry-cavernography in impotence. Brit. J. Urol., 5 8 429, 1986. 14. Lue, T. F., Hricak, H., Schmidt, R. A. and Tanagho, E. A.: Functional evaluation of penile veins by cavernosography in papaverine-induced erection. J. Urol., 135: 479, 1986. 15. Padma-Nathan, H.:Evaluation of the corporal veno-occlusive mechanism: dynamic infusion cavernosometry and cavernosography. Sem. Intervent. Rad., 6 205, 1989. 16. Stief, C. G., Wetterauer, U. and Sommerkamp, H.: Intraindividual comparative study of dynamic and pharmacocavernography. Brit. J. Urol., 64:93,1989. 17. Vickers, M.A.,Jr., Benson, C., Dluhy, R. and Ball, R. A,: The current cavernosometric criteria for corporavenous dysfunction are too strict. J. Urol., 147 614,1992. 18. Sasso, F., Gulino, G., Basar, M., Alcini, A. and Alcini, E.: Could standardized cavernosometry be helpful in therapeutic management of veno-occlusive dysfunction? J. Urol., 155: 150, 1996. 19. Wespes, E.,Moreira de Goes, P., Sattar, A. A. and Schulman, C. C.: Objective criteria in the long-term evaluation of penile venous surgery. J. Urol., 152 888,1994. 20. Stief, C. G.,Djamilian, M., Truss, M. C., Tan, H., Thon, W. F. and Jonas, U.: Prognostic factors for the postoperative outcome of penile venous surgery for venogenic erectile dysfunction. J. Urol., 151: 880,1994. 21. Wespes, E.,Depierreux, M. and Schulman, C. C.: Use of Biopty gun for corpus cavernosum biopsies. Eur. Urol., 18: 81, 1990. 22. Wespes, E.,de Goes, P. M. and Schulman, C. C.: Vascular impotence: focal or diffuse penile disease. J . Urol., 1 4 8 1435,1992. 23. Sattar, A. A.,Salpigides, G., Vanderhaeghen, J.-J., Schulman, C. C. and Wespes, E.: Cavernous oxygen tension and smooth muscle fibers: relation and function. J. Urol., 154: 1736,1995.
Vol. 157. 1678-1680,May 1997 Printed i n U.S.A
THE JOURNAL OF UROIBGY Copyright 0 1997 by AMERICAN UR0LXX;ICAL
~ C ~ A T I O INC. N .
CORPOREAL WNO-OCCLUSIVE DYSFUNCTION: PREDOMINANTLY INTRACAWRNOUS MUSCULAR PATHOLOGY ERIC WESPES, AHMED A. SATTAR, JAFAR GOLZARIAN, DIDIER WERY, NICOLAS DAOUD CLAUDE C. SCHULMAN From the Departments
of
AND
Urology, Radiology, and Haematology and Microbiology, Erasme Hospital, Brussels, Belgium
ABSTRACT
Purpose: We investigated whether a relationship exists between the flow to maintain a n erection obtained at cavernosometry and the alteration of intracavernous structures in impotent patients with corporeal veno-occlusive dysfunction and normal arterial inflow. Materials and Methods: Computerized histomorphometric analysis of smooth muscle and elastic fibers, and endothelial cells was compared to the flow necessary to maintain erection after intracavernous vasoactive drug injection in 18 patients with corporeal veno-occlusive dysfunction. Results: A significant correlation between percentage of smooth muscle fibers a n d flow to maintain erection was observed, while no correlation was noted with elastic fibers and endothelial cells. Conclusions: Corporeal veno-occlusive dysfunction seems to be due mainly to smooth muscular alterations. According to this observation treatment of impotent patients with this abnormality should not be restricted to the penile veins but should also include the intracavernous structures, predominantly the muscular component. Key
WORDS:impotence, venous insufficiency, histology, penile erection
Erection is a vascular phenomenon under neurological control modulated by a specific hormonal environment and occurring in a particular psychological context.' During tumescence the intracavemous smooth muscles are relaxed, producing arterial dilatation and filling of the lacunar spaces. Compression of the sub-albugineal venous plexus by the lacunar spaces against the tunica albuginea increases the resistance to flow through the emissary veins, which induces penile rigidity.2.3 Failure to trap arterial blood in the penis is a frequent abnormality in impotence, and it currently is the most challenging problem in the diagnosis and treatment of erectile dysfunction. Alteration of the intracavernous smooth muscles4-7 or in the fibroelastic components of the trabecula6 seems to be the underlying cause of this syndrome, which explains the failures observed with surgical treatment restricted to the penile veins.$ However, no modification of the percentage of endothelial cells was observed.10 To understand better and determine the best treatment for this condition we compared the percentage of the different intracavemous structures obtained by histomorphometric study (smooth muscle and elastic fibers, and endothelial cells) to the flow necessary to maintain erection at cavernosometry. MATERIAL A N D METHODS
Clinical investigations. A total of 18 men 39 to 73 years old (mean age 52) was diagnosed with pure venous leakage based on a detailed sexual history and physical examination. Full blood and hormonal assays were done to exclude endocrinological disease. Every patient spent a t least 1 night at the hospital to evaluate the nocturnal tumescence with the Rigiscan* device. Nocturnal penile tumescence was interpreted based on multiple parameters, including duration of recording longer than 5 hours a night, frequency of tumescence 1to 2 a night, duration of erection 10 minutes or longer, Accepted for publication September 27, 1996. * Dacomed. Minneapolis, Minnesota.
increase in penile tip and base length by 2.5 cm. or greater and penile rigidity 60%or greater at the tip and base. Duplex ultrasound (7.5 MHz. device) was used to obtain real-time images of the corpora cavernosa, and for visualization and Doppler calculations of the blood flow in the cavernous arteries. With the patient in the supine position the duplex probe was placed on the ventral side at the base of the penis, and a baseline image of the penis was obtained in the longitudinal and transverse planes, including measurements of blood flow in the cavernous arteries. A 20 pg. dose of prostaglandin E l was injected intracavernously using a 27% gauge needle. Blood flow in the cavernous arteries was measured a t approximately 2,5,10 and 20 minutes after injection, and peak and end diastolic velocities were determined. Peak systolic velocity greater than 35 cm. per second and end diastolic velocity less than 5 cm. per second demonstrated normal penile arterial inflow. Pharmacocavernosometry and pharmacocavernosography were performed with the patient supine on a n angiography table. A 19 gauge needle was inserted dorsolaterally in the right corpus cavernosum approximately halfway down the shaft and 20 pg. prostaglandin E l were injected. At 10 minutes after intracavernous injection body temperature physiological saline solution was injected through the needle with a high flow mechanical pump, with flow rates starting at 40 ml. per minute and increasing incrementally by 40 ml. per minute every minute until a full rigid erection was achieved. Rigid erection, evaluated subjectively by digital palpation, was sufficient for easy vaginal penetration. The flow rates needed to induce and maintain erection were recorded. A flow rate to maintain erection equivalent t o or greater than 15 ml. per minute was considered abnormal. Cavernosography was performed with injection of a low osmolality contrast medium diluted 1:4 with 2.500 p.A. heparinized saline solution to avoid a n y risk of thrombosis of the cavernous bodies. Serial films \yere t a k e n with a 100 mm. camera, and the corpora C ~ V W I I I I S ~a n d penile v e n o ~ i snetwork were studied i n thcx ohlicluc. ;md a n t c i . o p o s t ~ i i o projecr
1678
CORPOREAL -NO-OCCLUSIVE
tions At the end of the procedure the corpora were emptied by dixonnecting the needle to clear the contrast material. A sterile compression dressing was applied to prevent formation of a hematoma and stasis of the contrast medium. A pediatric cuff was inflated for 10 to 15 minutes to ensure effective compression. Tzssue processing. During vascular reconstruction or penile implantation a penile biopsy was obtained, the corpora were surgically opened and a small specimen under the tunica albuginea was resected. Light microscope evaluation and immunohistochemical staining were done. Following surgical removal cavernous biopsy specimens were immediately fixed in 10% formalin phosphate buffer solution, processed through xylene, embedded in paraffin and sectioned a t 5 pm. intervals. Four serial tissue sections were then used for hematoxylin and eosin staining and light microscopy to evaluate the cavernous tissue pathologically (11,for immunohistochemistry staining using factor VIII to determine the endothelial cells and actin anti-actin for smooth muscle fibers ( 2 ) , and for orcein staining for the elastic fibers (1).Immunohistochemical staining was used according to the biotinstreptavidin-peroxidase technique. The sections were incubated for 15 minutes with 2% (volume-in-volume)hydrogen peroxide solution to block endogenous peroxidase activity and processed for immunohistochemistry. After incubation with 1to 20 normal sheep serum, the sections were incubated overnight (14to 18 hours) with mouse anti-human factor VIII antibodies diluted 150 or with mouse anti-human antiactin antibodies diluted 1:50.After rinsing, the sections were incubated for 30 minutes at room temperature successively with sheep anti-mouse immunoglobulin biotin diluted 1:500 and with streptavidin, which is coupled to peroxidase 1:1,000 for 30 minutes. Peroxidase activity was revealed by 10 mg./lO ml. 3.3-diamin~henzidine~ pH 7.4, containing 0.01% (volumein-volume) hydrogen peroxide for 5 to 10 minutes at room temperature. Computerized image analysis. Quantitative analysis of endothelial cells, smooth muscle or elastic fibers in cavernous tissue was done with an image analyzer system combined with a light microscope equipped with a video camera. The images were interactively discriminated and the measurements were performed on the resulting binary images. The percentage of the structures for each image results from the quantification of the difference between the gray levels in the digitalized image. At least 20 different fields (X400)in the cavernous tissue were examined from each tissue section. The mean percentage was then considered.
1679
DYSFUNCTION
Cavernosomtry pammeter versus flow to maintain erection, and the percentage of cavermus smooth muscle fibers. elastic fibers and endothelial cells
kyz)
Flow Maintain pt'Age
60 52 56 73 35 50 51 58 70 44 39 70 47 53 44 50 43 39 Mean 51.88
100 50
40 40 20 40 20 25 20 15 50 80 40 80 50 80 80
40 48.33
% Smooth % Elastic % Endothelid Musclefibers Fibers Cells
19 21 19.6 22 32 27.7 28.3 26 30.7 33.2 21.4 22.4 24.6 19 27.2 22 23 26.4 24.75
5.5 6.3 5.4 4.7 6.2 5 5.3 4 3.3 4.4 3.9 4.7 6.2 5.3 4.2 6.7 3.8 4.2 4.95
2.7 2.2 1.4 4.6 3.3 1.8 2.2 3.9 2.6 2.5 3.5 2.4 3.8 1.6 4.3 3.4 2.6 2.8 2.86
of the trabecular smooth muscle, the basic structure in the mechanism of erection.1.2 Sufficient elasticity and compliance of the cavernous trabeculae are required for penile elongation. The intact lacunar space endothelial cells release endothelium-derived relaxing factor, which is diffused to the underlying smooth muscle causing its relaxation.12 This relaxation allows for expansion of the lacunar spaces and subsequent trapping of blood within the corpora due to compression of the subtunical venules by the dilated lacunar space^.^ Impotent patients may have adequate arterialinflow to the penis but excessive outflow through the cavernous subtunical venules. In these patients the corporeal veno-occlusive mechanism may not be functional, as diagnosed by pharmacoeavernosometry and cavernosography.13-14 These techniques have a major role in evaluating the degree of corporeal venous outflow resistance and demonstrating the routes of venous leak for planning of possible veno-ablative therapy. Indeed, these techniques should always be performed after smooth muscle relaxation by intracavernous vasoactive agent injection to obtain analogues to the physiological situation. During cavernosometry venous outflow resistance is assessed by determining the intracavemous flow rate of saline required to create or sustain an erection,l2.13 or by infusing saline to a suprasystolic intracavernous pressure and determining the rate of the pressure decrease after the infusion is RESULTS stopped.16 We relied predominantly on determination of the All patients had abnormal nocturnal tumescence, mainly infusion to maintain the erection and we standardized our characterized by short durations of tumescence and rigidity value as less than 15 ml.per minute. This maintenance flow greater than 60% a t the tip and base. They all had a normal rate used as the normal parameter was similar to that sugpeak systolic velocity of greater than 35 cm. per second but gested by others.16-18 a peak diastolic velocity of greater than 5 cm. per second. When flow to maintain the erection was compared to the Cavernosometry ranged from 15 to 100 ml. per minute percentage of cavernous smooth muscle fibers a relatively (mean 48.33, see table). The smooth muscle cell component good inversely proportional correlation was observed. The ranged from 19 to 28.3% (mean 24.75,normal plus or minus greater the percentage of cavernous smooth muscle, the standard deviation 45.2 5 3.2),8elastic fibers from 3.2 to lower the flow rate to maintain erection (part A of figure). 6.7% (mean 4.95,normal 9 2 2.5)" and endothelial cells from The other key factor in normal corporeal veno-occlusive 1.4to 4.6% (mean 2.86,normal 2.8 2 lU.10 dysfunction is the compliance of the trabecular fibmlastic A significant correlation was observed between the flow to frame. Its contribution is fixed and does not depend on the maintain erection and smooth muscle fibers (R2= 0.5777), degree of relaxation or contraction of the smooth muscle while no correlation was noted with the elastic fibers (R2= fibers but on intrinsic structural characteristics. A decrease 0.0402) and/or endothelial cells (R2= 0.0165,see figure). in elastic fibers has already been demonstrated in patients with veno-occlusive dysfunction8~but in our study no correDISCUSSION lation was observed between this decrease and the flow necThe intracavernous structures (cavernous smooth muscle essary to maintain the erection (part B of figure). This obserfibers, elastic fibers and endothelial cells) cooperate together vation demonstrated that elastic fibers may have a role in the with the penile vascular system to control the processes of physiopathological mechanism but this is certainly not of erection and flaccidity.'. 2 During erection there is relaxation crucial value as the role of the smooth musculature.
1680
CORPOREAL VENO-OCCLUSIVE DYSFUNCTION
I
I
I
. .
E
q'
I -
9'
i I: Ud--d
%d-dux6b
Xd--lr*h
B
A
C
Percent cavernous smooth muscle fiber(A), percent cavernous elastic fibers ( B )and percent cavernous endothelial cells correlated with flow to maintain erection.
Also, no correlation was noted between the endothelial cells and the flow to maintain erection (part C of figure). However, this observation did not exclude functional alteration of the endothelium and further investigations are required.I2 Indeed, these correlations could explain the importance of the percent of cavernous smooth muscle fibers in the diagnosis of the degree of caverno-venous leak, which could be an important factor that influences the surgical results. Most reports of surgery for venogenic impotence showed actual positive results of this surgery of less than 50%.IaPreviously, it was reported that impotent patients who underwent surgery due to caverno-venous dysfunction had good results when cavernous smooth muscle fibers were greater than 29%19or when good electromyography of the cavernous muscles was recorded.20 To study the intracavernous structures a small biopsy can be performed when vascular reconstruction is indicated.2' Morphometric analysis has already demonstrated no difference in the percentage of smooth muscle fibers in the different areas of the penis, meaning that vascular impotence is a diffuse disease.22 CONCLUSIONS
The question raised is what factor can influence the integrity of cavernous smooth muscle fibers and, consequently, the diagnosis of caverno-venous dysfunction. This phenomenon of caverno-venous dysfunction may be due to vascular injury although the cavernous arteries are normal when studied with Doppler ultrasound. The helicine arteries are not investigated with this technique and could be abnormal, which results in the formation of a state of ischemia and, consequently, fibrosis of the cavernous smooth muscle fibers.23 Further studies are needed to explain the observation of low cavernous oxygen tension in this phenomenon and its relationship to cavernous smooth muscle alteration. Venoocclusive dysfunction could be the first event in the pathophysiological process of arterial disease. It is possible that presently lack of a more sensitive method of evaluation of penile arterial flow might explain these findings. REFERENCES
1. Krane, R. J., Goldstein, I. and Saenz de Tejada, I.: Impotence. New Engl. J. Med., 321: 1648, 1989. 2. Lue,T. F. and Tanagho, E. A.: Physiology of erection and pharmacological management of impotence. J. Urol., 137: 829, 1987. 3. Fournier. G.R., Jr., Juenemann, K-P., Lue, T. F. and Tanagho, E. A: Mechanism of venous occlusion during canine penile erection: an anatomic demonstration. J. Urol., 137 163,1987. 4. Persson, C., Diederichs, W.. Lue, T. F., Yen, T. S. B., Fishman, I. J., McLin, P. H. and Tanagho, E. A.: Correlation of altered penile ultrastructure with clinical arterial evaluation. J. Urol., 142 1462.1989. 5. Jevtich, M. J., Khawand, N. Y. and Vidic, B.: Clinical signifi-
cance of ultrastructural findings in the corpora cavernosa of normal and impotent men. J. Urol., 143: 289,1990. 6. Mersdorf, A., Goldsmith, P. C., Diederichs, W.,Padula, C. A., Lue, T. F., Fishman, I. J. and Tanagho, E.A.: Ultrastructural changes in impotent penile tissue: a comparison of 65 patients. J. Urol., 145: 749,1991. 7. Wespes, E., Goes, P. M., Schiffmann, S., Depierreux, M., Vanderhaeghen, J.J. and Schulman, C. C.: Computerized analysis of smooth muscle fibers in potent and impotent patients. J. Urol., 1 4 6 1015,1991. 8. Sattar, A. A., Wespes, E. and Schulman, C. C.: Computerized measurement of penile elastic fibres in potent and impotent men. Eur. Urol., 25: 142, 1994. 9. Wespes, E. and Schulman, C. C.: Venous impotence: pathophysiology, diagnosis and treatment. J. Urol., 149 1238,1993. 10. Sattar, A. A.,Schulman, C. C. and Wespes, E.: Objective quantification of cavernous endothelium in potent and impotent men. J. Urol., 1 5 3 1136,1995. 11. Sattar, A. A,, Haot, J., Schulman, C. C. and Wespes, E.: Comparison of anti-desmin and anti-actin staining for the computerized analysis of cavernous smooth muscle density. Brit. J. Urol., 77: 266,1996. 12. Saenz de Tejada, I., Goldstein, I., Azadzoi, K., Krane, R. J. and Cohen, R. A.: Impaired neurogenic and endothelium-mediated relaxation of penile smooth muscle from diabetic men with impotence. New Engl. J. Med., 3 2 0 1025,1989. 13. Wespes, E., Delcour, C., Struyven, J. and Schulman, C. C.: Pharmacocavernometry-cavernography in impotence. Brit. J. Urol., 5 8 429, 1986. 14. Lue, T. F., Hricak, H., Schmidt, R. A. and Tanagho, E. A.: Functional evaluation of penile veins by cavernosography in papaverine-induced erection. J. Urol., 135: 479, 1986. 15. Padma-Nathan, H.:Evaluation of the corporal veno-occlusive mechanism: dynamic infusion cavernosometry and cavernosography. Sem. Intervent. Rad., 6 205, 1989. 16. Stief, C. G., Wetterauer, U. and Sommerkamp, H.: Intraindividual comparative study of dynamic and pharmacocavernography. Brit. J. Urol., 64:93,1989. 17. Vickers, M.A.,Jr., Benson, C., Dluhy, R. and Ball, R. A,: The current cavernosometric criteria for corporavenous dysfunction are too strict. J. Urol., 147 614,1992. 18. Sasso, F., Gulino, G., Basar, M., Alcini, A. and Alcini, E.: Could standardized cavernosometry be helpful in therapeutic management of veno-occlusive dysfunction? J. Urol., 155: 150, 1996. 19. Wespes, E.,Moreira de Goes, P., Sattar, A. A. and Schulman, C. C.: Objective criteria in the long-term evaluation of penile venous surgery. J. Urol., 152 888,1994. 20. Stief, C. G.,Djamilian, M., Truss, M. C., Tan, H., Thon, W. F. and Jonas, U.: Prognostic factors for the postoperative outcome of penile venous surgery for venogenic erectile dysfunction. J. Urol., 151: 880,1994. 21. Wespes, E.,Depierreux, M. and Schulman, C. C.: Use of Biopty gun for corpus cavernosum biopsies. Eur. Urol., 18: 81, 1990. 22. Wespes, E.,de Goes, P. M. and Schulman, C. C.: Vascular impotence: focal or diffuse penile disease. J . Urol., 1 4 8 1435,1992. 23. Sattar, A. A.,Salpigides, G., Vanderhaeghen, J.-J., Schulman, C. C. and Wespes, E.: Cavernous oxygen tension and smooth muscle fibers: relation and function. J. Urol., 154: 1736,1995.