Preview

Vestnik Urologii

Advanced search

Justification of vacuum prophylaxis as part of the penile rehabilitation in patients after nerve-sparing radical prostatectomy

https://doi.org/10.21886/2308-6424-2021-9-4-87-94

Abstract

Introduction. In healthy men, a significant increase in pO2 in the cavernous tissue occurs during episodes of nocturnal erections. This process ensures sufficient oxygenation and high-pressure substances such as prostaglandin-E1 and nitric oxide. These substances suppress the expression of transforming growth factor β1, thereby preventing collagen synthesis and the development of cavernous fibrosis. In patients undergoing nerve-sparing radical prostatectomy, nocturnal erections are absent, hypoxia inhibits the production of PGE-i, and neuropraxia inhibits NO. Thus, cavernous fibrosis develops through the production of pro-apoptotic and profibrotic factors, resulting in persistent erectile dysfunction. The importance of a vacuum in penile rehabilitation for the prevention of penile cavernous hypoxia is not fully understood. This is due to the deficiency of data on the gas composition of cavernous blood when a vacuum-induced erection is achieved.

Purpose of the study. To investigate the cavernous blood at the time of vacuum-induced erection, to analyze the obtained results with the International Index of Erectile Function score and with the values of penile hemodynamics.

Materials and methods. The study included i5 patients with prostate cancer and preserved sexual function. The average age of all men was 57.87 ±4.36 years. All patients underwent a preoperative comprehensive assessment of erectile function: International Index of Erectile Function questionnaire, dynamic duplex penile ultrasound. Immediately prior to the surgery, penile blood was collected at the time of achieving a vacuum-induced erection. The gas composition and oxygenation were assessed using the values of the partial oxygen pressure, carbon dioxide and saturation in accordance with the approved standards to differentiate arterial and venous blood. Statistical data processing was carried out using the PASW Statistics 22 software (IBM SPSS, IBM Corp., Chicago, IL, USA)

Results. All patients were divided into 3 groups depending on the gas composition and oxygen level of the cavernous blood. Group I included 4 (26.6%) patients with a predominance of arterial blood, group II — 4 patients (26.6%) with venous blood and group III — 7 patients (46.6%) with a mixed composition of cavernous blood. The average International Index of Erectile Function score in group I was 23.5 [2i.0; 25.0], in group II — 22.0 [2i.0; 24.0] and in group III — 24.0 [i9.0; 25.0]. Peak systolic velocity (cm/s) in group I was 40.i [35.i; 45.2], in group II — 35.9 [29.5; 50.2], in group III — 32.5 [32.5; 34.4]. End-diastolic velocity (cm/s) in group I was 2.52 [0.55; i0.5], in group II — 8.3 [2.9; i0.8], in group III — 7.5 [7.5; 9.0]. Resistive index in group I was 0.87 [0.77; 0.98], in group II — 0.75 [0.63; 0.94], in group III — 0.75 [0.73; 0.75].

Conclusions. Vacuum prophylaxis may be the method of choice for penile rehabilitation in patients after nerve-sparing radical prostateectomy, especially in the early postoperative period during neuropraxia. The use of vacuum devices should be prescribed to patients with preserved veno-occlusive mechanism, which should be confirmed by dynamic duplex penile ultrasound.

For citation:


Osadchinskiy A.E., Pavlov I.S., Kotov S.V. Justification of vacuum prophylaxis as part of the penile rehabilitation in patients after nerve-sparing radical prostatectomy. Vestnik Urologii. 2021;9(4):87-94. (In Russ.) https://doi.org/10.21886/2308-6424-2021-9-4-87-94

Introduction

The normal physiological condition of the non-erected penis in men with preserved erectile function (EF) is interrupted by regular episodes of nocturnal erection [1]. Most of the time, partial oxygen pressure (рO2) in a flaccid penis is 25 – 40 mmHg [2]. However, during episodes of nocturnal erection (on average, 3 – 5 times per night, 30 – 45 minutes each, which is 1.5 hours), рO2 in cavernous bodies increases to 90 – 100 mmHg [3]. Due to a high level of рO2, oxygenation (SO2) also increases. This process ensures the release of high-pressure substances such as prostaglandin-E1 and nitric oxide that suppress the expression of transforming growth factor β1, thereby preventing collagen synthesis and the development of cavernous fibrosis in the smooth muscles [4][5]. Patients that underwent nerve-sparing radical prostatectomy (nsRPE) have no episodes of nocturnal erections. Hypoxia inhibits the expression of PGE-1 and neuropraxia inhibits the expression of NO. The production of pro-apoptotic and pro-profibrotic factors promotes the development of cavernous fibrosis with the development of persistent erectile dysfunction (ED). To minimize the damage of cavernous tissue and provide early restoration of EF in the postoperative period, it is necessary to provide sufficient oxygenation in the cavernous tissue [6]. Currently, the most common method of prevention and treatment for ED is pharmacotherapy with phosphodiesterase type 5 inhibitors (PDE-5 inhibitors). The role of vacuum in penile rehabilitation (PR) in the prevention of cavernous hypoxia remains unclear because of the lack of data on gases composition in the cavernous blood during vacuum-induced erection (VIE) [7][8].

The study aimed to investigate the cavernous blood at the time of vacuum-induced erection, to analyze the obtained results with the International Index of Erectile Function score and with the values of penile hemodynamics.

Materials and methods

The study included 15 patients with prostate cancer (PCa) and preserved sexual function. The average age of men was 57.87 ± 4.36 years old. All patients before surgery (bilateral nsRPE) underwent complex evaluation of EF that included International Index of Erectile Function (IIEF) questionnaire, and penile dynamic duplex ultrasonography (Table 1). The assessment of penile hemodynamics with penile dynamic duplex ultrasonography included peak systolic velocity (PSV), end-diastolic velocity (EDV), and resistance index (RI).

Table 1. Patient demographics

Characteristics

Value

Number of patients

15

Mean age, yrs (M + SD)

57.87 ± 4.36

Preoperative total PSA level, ng/ml (Me [LQ; UQ])

6.2 [5.1; 7.5]

IIEF, mean (M + SD)

22.14 ± 3.21

Parameters of penile hemodynamics measured with dynamic duplex ultrasound:

PSV, mean cm/s (M + SD)

38.0 ± 9.20

EDV, mean cm/s (M + SD)

7.11 ± 3.78

RI mean (M + SD)

0.81 ± 0.13

Note: 1) M — mean; SD — standard deviation; PSA — prostate-specific antigen; Ме — median; LQ — 25% percentile; UQ — 75% percentile. 2) IIEF — international index of erectile function; PSV — peak systolic velocity; EDV — end-diastolic velocity; RI — resistive index.

Cavernous blood sampling was performed directly before bilateral nsRPE during anesthetic induction. During this manipulation, patients were on a surgical table. When VIE was achieved with a vacuum pump (Fig. 1), a puncture in a cavernous body was made on the dorsolateral surface of the penis (Fig. 2). A vacutainer (5.0 ml) with anticoagulant was used for blood sampling. Blood samples were delivered to the laboratory to study the gases composition and oxygenation by the assessment of pO2, pCO2, and saturation (satO2). The blood assay was conducted without storing the sample in strict temperature conditions.

To control the reliability of the results, cavernous blood assay included such parameters as pH of venous and arterial blood that were sampled simultaneously. Venous blood was sampled from the cubital vein and arterial blood — from the radial artery. These blood samples were also delivered to the laboratory.

Figure 1. Creating a vacuum-induced erection

Figure 2. Cavernous blood sampling

Statistical analysis. Statistical data processing was performed using the PASW Statistics 22 software (IBM SPSS, IBM Corp., USA). Descriptive statistics was presented as the mean and standard deviation, median 25 and 75 percentiles — Me [ 25%; 75%], minimal and maximal values in the sampling for qualitative variables. Numerous comparisons of qualitative data in the associated samplings were performed with a non-parametric Friedman’s test and two associated samplings were analyzed with a non-parametric Wilcoxon’s test. The differences were significant at p = 0.05 in all groups.

Results

Depending on the gases composition and the level of oxygenation in the cavernous blood, all patients were distributed into three groups. Group I included 4 (26.7%) patients with the parameters of their cavernous blood that corresponded with the parameters of arterial blood, Group II included 4 (26.7%) patients with the parameters of venous blood, and Group III — 7 (46.7%) patients with the mixed composition of cavernous blood.

The blood parameters, IIEF score, and penile hemodynamic values are presented in Table 2.

Table 2. Study results distributed by groups

Characteristics

Group I

Group II

Group III

Number of patients

4 (26.7%)

4 (26.7%)

7 (46.7%)

Blood composition in cavernous bodies after vacuum-induced erection

Arterial

Venous

Mixed

pO2 in cavernous tissue, mmHg.

85.9 [ 84.5; 88.6]

55.3 [ 47.3; 62.8]

68.1 [ 65.3; 93.2]

pO2 from a. radialis, mmHg.

97.8 [ 96.9; 98.5]

98.5 [ 97.9; 99.1]

98.7 [ 97.9;100.0]

pСO2 in cavernous tissue, mmHg.

38.6 [ 30.7; 40.5]

48.5 [ 44.5; 51.5]

42.8 [ 40.3; 45.2]

pСO2 from v. cubitalis, mmHg.

41.8 [ 38.35; 45.4]

50.75 [ 45.9; 54.1]

42.3 [ 42.0; 53.1]

IIEF score

23.5 [ 21.0; 25.0]

22.0 [ 21.0; 24.0]

24.0 [ 19.0; 25.0]

PSV, cm/s

40.1 [ 35.05; 45.1]

35.9 [ 29.4; 50.1]

32.5 [ 32.5; 34.3]

EDV, cm/s

2.52 [ 0.55; 10.5]

8.3 [ 2.92; 10.7]

7.5 [ 7.5; 8.9]

RI

0.87 [ 0.77; 0.98]

0.75 [ 0.63; 0.94]

0.75 [ 0.73; 0.75]

Note: pO2 — partial pressure of oxygen; pCO2 — partial pressure of carbon dioxide; IIEF — international index of erectile function; PSV — peak systolic velocity; EDV — end-diastolic velocity; RI — resistive index.

Discussion

Currently, there are no precise guidelines on the choice of the method of prophylaxis within the program of penile rehabilitation in patients after nsRPE [9]. The restoration of erection sufficient for sexual intercourse at the early postoperative period is a marker of successful penile rehabilitation. The application of vacuum devices is a relatively understudied method of prevention of erectile dysfunction in comparison with the indication of PDE-5 inhibitors. It is considered that vacuum-prophylaxis contributes to the minimization of damage to the cavernous tissue within the period of neuropraxia due to the maintenance of a sufficient level of oxygenation. Nadig et al. studied ED treatment. The study results showed that 91% of patients reported rigidity of the penis sufficient for sexual intercourse after the application of vacuum devices [10]. Derouet et al. also demonstrated that 85% of patients were satisfied with vacuum devices [11]. Zippe et al. were one of the first researchers that showed the restoration of EF after RPE in the prospective study. So, 80% of patients could have sexual intercourse twice a week after daily application of the vacuum device. Natural erections developed in 55% of men after nine months of daily application of vacuum devices [12].

The present study demonstrated that in patients with the prevalence of the arterial component (pO2 = 85.9 [ 84.5; 88.6] mmHg), PSV was higher than in other groups. In group I, RI met the normal value (0.87 [ 0.77; 0.98]), which demonstrated the functional capacity of the veno-occlusive mechanism and lack of a venous leak. Significant results obtained in Group I suggest the feasibility of the application of vacuum devices as a part of a program of penile rehabilitation in patients after nsRPE.

Hoyland et al. published the data that 59% of patients after RPE develop arterial insufficiency and 26% of patients have a venous leak caused by dysfunction of the veno-occlusive mechanism [13]. Broderick et al. used color dynamic Doppler ultrasonography in their study and showed that negative pressure increased the blood flow velocity in deep cavernous arteries [14].

According to the values of partial pressure of oxygen and carbon dioxide, 26.6% of patients had a prevalence of the venous component in the cavernous blood during VIE. The parameters of penile hemodynamics in patients from this group (EDV — 8.3 [ 2.92; 10.7] cm/s and RI — 0.75 [ 0.63; 0.94]) indicate dysfunction of veno-occlusive mechanism, which leads to a decrease in pO2 in the cavernous tissue. During VIE, passive blood afflux is observed due to negative pressure, but the force of pumping was not considered. Probably, a fast increase in negative pressure caused afflux of the venous component to the cavernous bodies. It is suggested that the application of vacuum devices in this group of patients is not feasible. In 2019, a group of authors from China conducted a study on rat models and showed that the pressure of 200 mmHg is optimal for vacuum devices used for penile rehabilitation. High pressure (300 – 500 mmHg) often caused complications [15].

According to the values pO2 and pCO2, 46.6% of patients had a mixed composition of cavernous blood. Hemodynamic parameters in patients from this group (EDV — 7.5 [ 7.5; 8.9] and RI — 0.75 [ 0.73; 0.75]) also indicated incapacity of veno-occlusive mechanism.

Padmanabhan et al. used a tissue oximeter to assess oxygenation in the cavernous bodies. Group I included 27 men with preserved EF (SHIM > 21) and Group II included 144 patients with mild ER (SHIM < 21). It should be mentioned that among patients, 59 patients underwent nsRPE, five of them were included in Group I. The authors concluded that saturation of cavernous tissue with SO2 in patients with ED is lower than in patients with normal EF regardless of the risk factors [16].

Conclusion

Vacuum prophylaxis of erectile dysfunction can be the method of choice in the program of penile rehabilitation in patients with nsRPE, especially in the early postoperative period during neuropraxia. The application of vacuum devices is feasible only in patients with the preserved veno-occlusive mechanism for the prevention of the cavernous body hypoxia, which must be verified using penile dynamic Doppler ultrasonography. In the present study, 73% of patients with decreased parameters of penile hemodynamics (EDV and RI) had a venous or mixed gases composition in the cavernous blood. In these cases, vacuum therapy is not feasible for penile rehabilitation.

References

1. Qian SQ, Gao L, Wei Q, Yuan J. Vacuum therapy in penile rehabilitation after radical prostatectomy: review of hemodynamic and antihypoxic evidence. Asian J Androl. 2016;18(3):446-51. DOI: 10.4103/1008-682X.159716.

2. Kim N, Vardi Y, Padma-Nathan H, Daley J, Goldstein I, Saenz de Tejada I. Oxygen tension regulates the nitric oxide pathway. Physiological role in penile erection. J Clin Invest. 1993;91(2):437-42. DOI: 10.1172/JCI116220.

3. Fisher C, Gorss J, Zuch J. Cycle of penile erection synchronous with dreaming (REM) sleep: preliminary report. Arch Gen Psychiatry. 1965; 12:29-45. DOI: 10.1001/archpsyc.1965.01720310031005.

4. Kogan M. I., Popov I. V., Popov I. V., Todorov S. S. Penile cavernous fibrosis: etiology, morphogenesis, erectile dysfunction. Urologiia. 2020;(4):144-50. (In Russ.). DOI: 10.18565/urology.2020.4.144-150.

5. Moreland RB. Is there a role of hypoxemia in penile fibrosis: a viewpoint presented to the Society for the Study of Impotence. Int J Impot Res. 1998;10(2):113-20. DOI: 10.1038/sj.ijir.3900328.

6. Clavell-Hernandez J, Wang R. The controversy surrounding penile rehabilitation after radical prostatectomy. Transl An-drol Urol. 2017;6 (1):2-11. DOI: 10.21037/tau.2016.08.14.

7. Qian SQ, Qin F, Zhang S, Yang Y, Wei Q, Wang R, Yuan JH. Vacuum therapy prevents corporeal veno-occlusive dysfunction and penile shrinkage in a cavernosal nerve injured rat model. Asian J Androl. 2020;22(3):274-279. DOI: 10.4103/aja.aja_57_19.

8. Osadchinskii A. E., Vinogradov I. V., Darenkov S. P. Vacuum therapy — prevention of hypoxia of cavernous tissue patients after radical prostatectomy. Vestnik Urologii. 2018;6(1):48-54. (In Russ.). DOI: 10.21886/2308-6424-2018-6-1-48-54

9. Salonia A, Bettocchi C, Boeri L, Capogrosso P, Carvalho J, Cilesiz NC, Cocci A, Corona G, Dimitropoulos K, Gul M, Hatzichristodoulou G, Jones TH, Kadioglu A, Martinez Salamanca JI, Milenkovic U, Modgil V, Russo GI, Serefoglu EC, Tharakan T, Verze P, Minhas S; EAU Working Group on Male Sexual and Reproductive Health. European Association of Urology Guidelines on Sexual and Reproductive Health-2021 Update: Male Sexual Dysfunction. Eur Urol. 2021;80(3):333-357. DOI: 10.1016/j.eururo.2021.06.007.

10. Nadig PW, Ware JC, Blumoff R. Noninvasive device to produce and maintain an erection-like state. Urology. 1986;27(2):126-31. DOI: 10.1016/0090-4295(86)90368-7.

11. Derouet H, Caspari D, Rohde V, Rommel G, Ziegler M. Treatment of erectile dysfunction with external vacuum devices. Andrologia. 1999;31 Suppl 1:89-94. DOI: 10.1111/j.1439-0272.1999.tb01456.x.

12. Zippe CD, Raina R, Thukral M, Lakin MM, Klein EA, Agarwal A. Management of erectile dysfunction following radical prostatectomy. Curr Urol Rep. 2001;2(6):495-503. DOI: 10.1007/s11934-001-0045-5.

13. Hoyland K, Vasdev N, Adshead J. The use of vacuum erection devices in erectile dysfunction after radical prostatectomy. Rev Urol. 2013;15(2):67-71. PMID: 24082845; PMCID: PMC3784970.

14. Broderick GA, McGahan JP, Stone AR, White RD. The hemodynamics of vacuum constriction erections: assessment by color Doppler ultrasound. J Urol. 1992;147(1):57-61. DOI: 10.1016/s0022-5347(17)37132-x.

15. Yang XL, Yang Y, Fu FD, Wu CJ, Qin F, Yuan JH. Optimal pressure in penile rehabilitation with a vacuum erection device: evidence based on a rat model. Asian J Androl. 2019;21(5):516-521. DOI: 10.4103/aja.aja_7_19.

16. Padmanabhan P, McCullough AR. Penile oxygen saturation in the flaccid and erect penis in men with and without erectile dysfunction. J Androl. 2007;28(2):223-8. DOI: 10.2164/jandrol.106.001313.


About the Authors

A. E. Osadchinskiy
Bashkir State Medical University
Russian Federation

Alexander E. Osadchinskiy — M. D.; Postgrad. Student, Dept. of Urology, Bashkir State Medical University.

450008, Republic of Bashkortostan, Ufa, 3 Lenin St.


Competing Interests:

The authors declare no conflicts of interest. 



I. S. Pavlov
Pirogov Russian National Research Medical University (Pirogov Medical University)
Russian Federation

Ivan S. Pavlov — Resident, Dept. of Urology and Andrology, Pirogov Russian National Research Medical University (Pirogov Medical University).

117997, Moscow, 1 Ostrovityanova St.


Competing Interests:

The authors declare no conflicts of interest. 



S. V. Kotov
Pirogov Russian National Research Medical University (Pirogov Medical University)
Russian Federation

Sergey V. Kotov — M. D., Dr.Sc. (Med), Full Prof.; Head, Dept. of Urology and Andrology, Pirogov Russian National Research Medical University (Pirogov Medical University).

117997, Moscow, 1 Ostrovityanova St.


Competing Interests:

The authors declare no conflicts of interest. 



Review

For citation:


Osadchinskiy A.E., Pavlov I.S., Kotov S.V. Justification of vacuum prophylaxis as part of the penile rehabilitation in patients after nerve-sparing radical prostatectomy. Vestnik Urologii. 2021;9(4):87-94. (In Russ.) https://doi.org/10.21886/2308-6424-2021-9-4-87-94

Views: 175


Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.


ISSN 2308-6424 (Online)