urovestUrology HeraldВестник урологии2308-6424Rostov State Medical University10.21886/2308-6424-2021-9-4-87-94urovest-498Research ArticleORIGINAL ARTICLESОРИГИНАЛЬНЫЕ СТАТЬИJustification of vacuum prophylaxis as part of the penile rehabilitation in patients after nerve-sparing radical prostatectomyОбоснование применения вакуум-профилактики эректильной дисфункции с целью пенильной реабилитации пациентов после нервосберегающей радикальной простатэктомииhttps://orcid.org/0000-0003-2892-5665ОсадчинскийА. Е.OsadchinskiyA. E.
Осадчинский Александр Евгеньевич — аспирант кафедры урологии с курсом ИДПО БГМУ Минздрава России.
450008, Республика Башкортостан, Уфа, ул. Ленина, д. 3.
Alexander E. Osadchinskiy — M. D.; Postgrad. Student, Dept. of Urology, Bashkir State Medical University.
450008, Republic of Bashkortostan, Ufa, 3 Lenin St.
osadchinskiy@gmail.comhttps://orcid.org/0000-0003-2389-4118ПавловИ. С.PavlovI. S.
Павлов Иван Сергеевич — клинический ординатор кафедры урологии и андрологии РНИМУ им. Н.И. Пирогова Минздрава России.
117997, Москва, ул. Островитянова, д. 1.
Ivan S. Pavlov — Resident, Dept. of Urology and Andrology, Pirogov Russian National Research Medical University (Pirogov Medical University).
117997, Moscow, 1 Ostrovityanova St.
dr.pavlov.urology@gmail.comhttps://orcid.org/0000-0003-3764-6131КотовС. В.KotovS. V.
Котов Сергей Владиславович — доктор медицинских наук, профессор; заведующий кафедрой урологии и андрологии РНИМУ им. Н.И. Пирогова Минздрава России.
117997, Москва, ул. Островитянова, д. 1.
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.
urokotov@mail.ruБашкирский государственный медицинский университет Минздрава РоссииРоссияBashkir State Medical UniversityRussian FederationРоссийский национальный исследовательский медицинский университет им. Н.И. Пирогова Минздрава РоссииРоссияPirogov Russian National Research Medical University (Pirogov Medical University)Russian Federation202123122021948794Copyright © Osadchinskiy A.E., Pavlov I.S., Kotov S.V., 20212021Осадчинский А.Е., Павлов И.С., Котов С.В.Osadchinskiy A.E., Pavlov I.S., Kotov S.V.This work is licensed under a Creative Commons Attribution 4.0 License.https://www.urovest.ru/jour/article/view/498Introduction
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
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
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
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
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.
Введение
Введение. У здоровых мужчин во время эпизодов ночных эрекций происходит значительное повышение уровня рО2 в кавернозной ткани. Этот процесс обеспечивает достаточный уровень оксигенации и веществ, выделяемых под действием высокого давления, таких как простогландин-Е1 и оксид азота, подавляющих экспрессию трансформирующего фактора роста β1, тем самым предотвращая синтез коллагена и развитие фиброза в кавернозной ткани. У пациентов, перенесших нервосберегающую радикальную простатэктомию, ночные эрекции отсутствуют, гипоксия ингибирует выработку PGE-1, а нейропраксия — NO. За счёт продукции проапоптических и профибротических факторов развивается кавернозный фиброз с возникновением стойкой эректильной дисфункции. Роль применения вакуума в пенильной реабилитации с целью профилактики гипоксии кавернозной ткани полового члена до конца не ясна из-за отсутствия данных о газовом составе кавернозной крови в момент достижения вакуум-индуцированной эрекции.
Цель исследования
Цель исследования. Исследовать кавернозную кровь в момент достижения вакуум-индуцированной эрекции, проанализировать данные результаты с показателями международного индекса эректильной функции и со значениями пенильной гемодинамики.
Материалы и методы
Материалы и методы. В исследование включены 15 пациентов с раком предстательной железы и сохранной половой функцией. Средний возраст мужчин составил 57,87 ± 4,36 лет. Всем пациентам проводили предоперационную комплексную оценку эректильной функции: заполнение анкеты международного индекса эректильной функции, фармакодопплерографию сосудов полового члена. Непосредственно перед операцией выполняли забор пенильной крови в момент достижения вакуум-индуцированной эрекции. Для дифференцировки артериальной и венозной крови проводили оценку газового состава и оксигенации за счёт определения значений парциального давления кислорода, углекислого газа и сатурации согласно утверждённым нормам. Статистическую обработку данных проводили с использованием программы PASW Statistics 22 (IBM SPSS, IBM Corp., Чикаго, ИЛ, США).
Результаты
Результаты. В зависимости от значений газового состава и уровня содержания кислорода кавернозной крови пациенты были распределены на три группы. В группу I вошли 4 (26,7%) пациента с преобладанием артериальной крови, в группу II — 4 (26,7%) пациента с венозной кровью и в группу III — 7 (46,7%) пациентов со смешанным составом кавернозной крови. Средний балл международного индекса эректильной функции в группе I составил 23,5 [21,0; 25,0], в группе II — 22,0 [21,0; 24,0] и в группе III — 24,0 [19,0; 25,0]. Пиковая систолическая скорость (см/с) в группе I составила 40,1 [35,1; 45,2], в группе II — 35,9 [29,5; 50,2], в группе III — 32,5 [32,5; 34,4]. Конечно-диастолическая скорость в группе I составила 2,52 [0,55; 10,5], в группе II — 8,3 [2,9; 10,8], в группе III — 7,5 [7,5; 9,0]. Индекс резистентности в группе I составил 0,87 [0,77; 0,98], в группе II — 0,75 [0,63; 0,94], в группе III — 0,75 [0,73; 0,75].
Заключение
Заключение. Вакуум-профилактика эректильной дисфункции может быть методом выбора программы пенильной реабилитации у пациентов после нервосберегающей радикальной простатэктомии, особенно на раннем послеоперационном этапе в период нейропраксии. Применение вакуумных устройств целесообразно назначать только пациентам с сохранным вено-окклюзивным механизмом, что должно быть подтверждено с помощью фармакодопплерографии сосудов полового члена.
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.
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.
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The authors declare that there are no conflicts of interest present.