|Year : 2021 | Volume
| Issue : 2 | Page : 77-82
Early penile rehabilitation with a vacuum erectile device in patients undergoing robotic-assisted radical prostatectomy: A randomized trial
Supichamon Rujinithiwat, Manint Usawachintachit, Kamol Panumatrassamee, Apirak Santingamkun, Kavirach Tantiwongse
Division of Urology, Department of Surgery, Faculty of Medicine, Chulalongkorn University, King Chulalongkorn Memorial Hospital, The Thai Red Cross Society, Bangkok, Thailand
|Date of Submission||10-Aug-2020|
|Date of Decision||20-Nov-2020|
|Date of Acceptance||15-Jan-2021|
|Date of Web Publication||22-Jun-2021|
Division of Urology, Department of Surgery, Faculty of Medicine, Chulalongkorn University, King Chulalongkorn Memorial Hospital, The Thai Red Cross Society, Rama IV Road, Patumwan, Bangkok,
Source of Support: None, Conflict of Interest: None
Purpose: This aim was to study the efficacy of a vacuum erectile device (VED) in rehabilitating the erectile function of patients undergoing nerve-sparing robotic-assisted radical prostatectomy. Materials and Methods: This prospective randomized study enrolled 35 prostate cancer patients from Thailand who had intact baseline erectile function and underwent nerve-sparing robotic-assisted radical prostatectomy. These patients were randomly assigned into either a study group which applied the VED for 10 min daily for 6 months or a control group which received no additional interventions. A 5-item version of the International Index of Erectile Function (IIEF-5) score, stretched penile length, and midshaft circumference were measured at 1, 3, and 7 months after surgery, respectively. Results: The mean patient age was 65.6 years, and the mean baseline IIEF-5 score was 22.91, which were comparable between the two groups. Three patients in the study group did not follow the VED protocol due to postoperative urinary incontinence. A per-protocol analysis revealed that the mean IIEF-5 score at 7 months was significantly higher in the study group compared to the control group (11.29 ± 7.47 vs. 6.61 ± 5.33, P = 0.047). The mean midshaft circumference was also higher in the study group (9.24 ± 1.43 cm vs. 7.91 ± 0.37 cm, P = 0.002). No statistically significant difference in the mean stretched penile length between the two groups was found. Conclusion: Early VED usage for penile rehabilitation following radical prostatectomy significantly improves IIEF-5 score and better preserves penile circumference but not penile length. A larger-scale multi-institutional study is required to validate these findings.
Keywords: Erectile dysfunction, penile rehabilitation, robotic-assisted radical prostatectomy, vacuum erectile device
|How to cite this article:|
Rujinithiwat S, Usawachintachit M, Panumatrassamee K, Santingamkun A, Tantiwongse K. Early penile rehabilitation with a vacuum erectile device in patients undergoing robotic-assisted radical prostatectomy: A randomized trial. Urol Sci 2021;32:77-82
|How to cite this URL:|
Rujinithiwat S, Usawachintachit M, Panumatrassamee K, Santingamkun A, Tantiwongse K. Early penile rehabilitation with a vacuum erectile device in patients undergoing robotic-assisted radical prostatectomy: A randomized trial. Urol Sci [serial online] 2021 [cited 2022 Aug 13];32:77-82. Available from: https://www.e-urol-sci.com/text.asp?2021/32/2/77/318995
| Introduction and Objectives|| |
Prostate cancer is one of the most common malignancies affecting men aged >50 years. At the localized stage, treatment with radical prostatectomy offers a high cure rate. Robotic-assisted radical prostatectomy has been increasingly performed due to the advantages of faster recovery and less postoperative pain compared to the traditional open approach. Nevertheless, major long-term complications may develop postoperatively, including urinary incontinence and erectile dysfunction.
Erectile dysfunction following treatment of prostate cancer dramatically affects a patient's quality of life and self-confidence. Some studies have shown that the penile morphology is worsened due to a lack of full erection for an extended period. Several methods, known as “penile rehabilitatio1,“ were introduced to improve erectile function after radical prostatectomy. They include the advent of “nerve-sparing” surgery, use of a phosphodiesterase-5 (PDE-5) inhibitor, intracavernosal injection therapy, and vacuum erectile devices (VEDs).
VED uses negative pressure to increase the blood flow and oxygenation into the penis. Daily use of VED after radical prostatectomy, either with or without constriction ring, helps the patient to achieve vaginal intercourse and has few complications. Moreover, the daily use of VED following radical prostatectomy facilitates the early return to sexual intercourse and sexual satisfaction. Furthermore, VED is more economically advantageous compared to a PDE-5 inhibitor, which is not reimbursable in most countries and may be medically prohibited in some patients with preexisting conditions.
Most studies on penile rehabilitation with VED were conducted retrospectively. Different approaches for radical prostatectomy, including open, laparoscopic, and robotic-assisted surgeries, are utilized and may cause selection bias. Some studies used PDE-5 inhibitors in addition to VED to demonstrate the success. Moreover, nerve-sparing status was mixed or was not clearly stated., Importantly, almost all studies were conducted in patients from western countries,,, which may have different penile characteristics and sexual cultures compared to patients from Asian countries. Thus, this study aimed to evaluate the efficacy of VED in erectile function restoration among Thai men undergoing nerve-sparing robotic-assisted prostate cancer surgery.
| Materials and Methods|| |
This single-institution prospective randomized study was conducted at a university-based tertiary care hospital in Bangkok, Thailand, between February 2018 and February 2019. Institutional research board approval was obtained prior to study initiation (IRB# 496/62). We enrolled patients with localized prostate cancer aged between 50 and 75 years who were sexually active, able to obtain a partial or full erection, and planned to undergo nerve-sparing robotic-assisted radical prostatectomy. We excluded patients with moderate or severe erectile dysfunction defined by a score <12 on a 5-item version of the International Index of Erectile Function (IIEF-5). Patients with penile curvature, history of priapism, and bleeding disorder were also excluded. We obtained baseline characteristics, including demographic data, preoperative prostate-specific antigen (PSA) value, and Gleason score.
After obtaining informed consent, a research assistant allocated the patients under a 1:1 ratio using a four-block randomization to either the study group using VED or the control group. We recorded baseline IIEF-5 scores using a validated local language version. Preoperatively, two penile parameters were measured in a flaccid stage, stretched penile length, and midshaft circumference, using an unmarked paper ruler. Stretched penile length was measured from the root of the penis to the tip of the glans on the dorsal surface, while maximally extending the penis and pushing the pubic-fat pad toward the bone. Midshaft circumference was measured at the midshaft of the penis without any stretching. Duplication of each of the three measurements was completed, with the average value recorded. One general physician who was unaware of the randomization assignment evaluated the penile morphometrics to reduce any measurement bias.
Robotic-assisted radical prostatectomy was performed by one of the two robotic surgeons using the da Vinci Si surgical system (Intuitive Surgical Inc., Sunnyvale, CA, United States), with either unilateral or bilateral nerve-sparing approach. The conventional (non-Retzius sparing) approach was utilized in all procedures. One month postoperatively, patients in the study group were instructed to begin using the VED without constriction ring for 10 min daily for 6 months. No additional penile rehabilitation device was provided to the control group. In both the groups, the use of a PDE-5 inhibitor was prohibited during the study period. Follow-up visits were conducted at 1-, 4-, and 7-month intervals postoperatively. At each visit, an IIEF-5 score was collected, stretched penile length and midshaft circumference were measured, and the patients in the study group were assessed for any adverse effects resulting from VED use.
The primary study endpoint was the difference in IIEF-5 scores at 7 months. The secondary endpoints included the difference in stretched penile length, midshaft circumference, and any reported adverse events resulting from VED use. For sample size calculation, we based our findings on a previous study. Setting the power at 90% to detect a significant difference in IIEF score, a sample size of 36 with 18 patients in each group was required.
Data analysis was performed using IBM SPSS Statistics 18.0 (IBM Corporation, Armonk, NY, United States). Chi-square test, Student's t-test, and Mann–Whitney U-test were utilized with statistical significance indicated at P < 0.05.
| Results|| |
A total of 35 patients were enrolled in the study (17 in the study group and 18 in the control group). The mean age at surgery was 65.6 ± 5.81 years. Clinical prostate cancer staging ranged from T1c to T2b, with a mean preoperative PSA value of 11.37 ± 6.18 ng/dL. The mean baseline IIEF-5 score was 22.91 ± 4.36, the mean stretched penile length was 9.07 ± 2.03 cm, and the mean midshaft circumference was 8.48 ± 1.09 cm. All patients underwent nerve-sparing robotic-assisted radical prostatectomy without significant intraoperative complications. Unilateral nerve-sparing surgery was performed in eight patients (22.9%), and bilateral nerve-sparing surgery was performed in 27 patients (77.1%). All prostatectomy specimens showed negative surgical margins. Baseline preoperative data were not different between study and control groups [Table 1].
|Table 1: Baseline demographic data, International Index of Erectile Function-5 score, stretched penile length, and midshaft circumference (intention to treat analysis)|
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Following surgery, three patients in the study group violated the study protocol by not utilizing the VED due to transient urinary incontinence in the early postoperative period. Thus, we separately evaluated the data by intention-to-treat analysis (17 patients in the study group and 18 patients in the control group) and per-protocol analysis (14 patients in the study group and 18 patients in the control group). With the per-protocol analysis, there were no statistically significant differences in baseline demographics, preoperative IIEF-5 score, stretched penile length, and midshaft circumference [Table 2]. In the study group, compliance of VED use was good, and no patients complained of any adverse effect.
|Table 2: Baseline demographic data, International Index of Erectile Function-5 score, stretched penile length, and midshaft circumference (per-protocol analysis)|
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At 1 and 4 months postoperatively, the mean IIEF-5 score decreased in all patients without any significant difference between the two groups. However, at the end of the study, the mean IIEF score in the study group was significantly higher than in the control group with the per-protocol sample (11.29 vs. 6.61, P = 0.047) [Figure 1] and [Table 3]. Furthermore, 2 of 14 patients in the study group reported spontaneous erection at a 7-month visit, while no patient in the control group reported this occurrence.
|Table 3: Comparison of the mean International Index of Erectile Function-5 score between the study and control groups (per-protocol analysis)|
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|Figure 1: Comparison of the mean International Index of Erectile Function-5 score between the study and control groups (per-protocol analysis)|
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Penile shortening was observed at 1 month postoperatively. Then, the stretched penile length slowly increased over time and approached its original baseline length by 7 months. There were no statistical differences in stretched penile length between the study and control groups at any of the three time periods [Figure 2] and [Table 4].
|Table 4: Comparison of the mean stretched penile length between the study and control groups (per-protocol analysis)|
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|Figure 2: Comparison of the mean stretched penile length between the study and control groups (per-protocol analysis)|
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At 1 month, the mean midshaft circumference was not reduced and showed no difference between the two groups. The mean midshaft circumference was significantly higher in the study group compared to the control group at the 4-month (9.27 vs. 8.02 cm, P = 0.002) and 7-month visits (9.24 vs. 7.91 cm, P = 0.002). This finding was also observed in the intention-to-treat analysis [Figure 3] and [Table 5].
|Table 5: Comparison of the mean midshaft circumference between the study and control groups|
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|Figure 3: Comparison of the mean midshaft circumference between the study and control groups (per-protocol analysis)|
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| Discussion|| |
Following radical prostatectomy, erectile function impairment often immediately occurs due to cavernous nerve damage known as neuropraxia. This nerve damage can be caused by mechanical stretching during prostate retraction, ischemia secondary to a blood supply disruption, thermal injury by electrocautery, and inflammatory effects secondary to surgical trauma. Nerve-sparing dissection can be meticulously performed with robotic-assisted surgery, which offers advantages of higher optical magnification and greater range of instrument motion offered by EndoWrist. However, some degree of neuropraxia is inevitable due to the proximity of the cavernous nerves to the prostate. Although these nerves usually recover slowly and reach a renewed functional status in a few years, permanent loss of penile size may occur because of prolonged absence or decreased level of spontaneous nocturnal erection.
Several strategies for penile rehabilitation following radical prostatectomy are widely available to improve patient's quality of life. These methods include the use of PDE-5 inhibitors, intracavernosal injection, intraurethral suppository, VED, or combination therapy.
VED utilizes negative pressure to increase the penile blood flow and distend the corporal sinusoids. Additional use of a constriction ring around the base of the penis, referred to as a vacuum constriction device, helps patients to maintain full erection and achieve sexual intercourse. The increased penile blood flow elevates tissue oxygen level, thus reducing tissue hypoxia damage caused by cavernous nerve injury following prostatectomy. It may inhibit the cell apoptosis process and prevent corporal tissue fibrosis. In the last decade, VED has been widely investigated as an option for penile rehabilitation after radical prostatectomy. Its ability to produce direct mechanical erection circumvents the limitation of oral PDE-5 inhibitors, which requires intact and functioning cavernosal nerves to produce an erection. Moreover, VED is less invasive, more affordable, and more accepted by patients compared to intracavernosal injection.
At 7 months, we found that the mean IIEF-5 score was significantly higher in the study group compared to that in the control group. The erectile function score decreased postoperatively in both the groups. Then, the score showed increases at the 4- and 7-month time intervals. Despite better performance in the study group, IIEF-5 scores remained much lower than preoperative levels (23.29–11.29 in the study group and 22.28–6.61 in the control group).
Raina et al. prospectively randomized 109 patients undergoing radical prostatectomy into study group (n = 74) or no erectogenic group (n = 35). Patients in the first group utilized VED daily after catheter removal and applied the constriction ring only when attempting sexual intercourse. The majority of patients (80%) in the study group successfully used VED and constriction ring for intercourse, while the remaining patients discontinued treatment because of discomfort, inability to obtain an airtight seal, social inconvenience, or penile bruising. Similar to our finding, Raina et al. found that early VED use was associated with better recovery of erectile function. At 9 months, patients in the VED group had a mean IIEF-5 score of 16 ± 7.33, significantly better than that at the early postsurgical period of 4.8 ± 3.62. Simultaneously, patients in the control group had a mean IIEF-5 score of 11.17 ± 1.76, which was significantly lower than the VED group.
Penile length has been shown to decrease following radical prostatectomy. Munding et al. measured stretched penile length preoperatively and again 3 months postoperatively in 31 patients. At 3 months, the majority of men had a decrease in their stretched penile length, and half of them had shortening >1 cm. The possible explanations for penile shortening include removal of the prostatic urethra, prepubic scarring with shortening of the penile suspensory ligament, and fibrotic changes in the corporal body resulting from penile denervation and erectile dysfunction.,
Dalkin and Christopher evaluated the benefits of VED use on stretched penile length in 42 men undergoing radical prostatectomy. Participants were instructed to use VED daily, beginning on the day after catheter removal and continuing for 90 d. From this nonrandomized prospective study, men who used VED >50% of possible days had better preservation of penile length at the 90-d assessment. A randomized study from Raina et al. revealed that most patients in the VED group were satisfied with penile length when using VED.
In contrast, our study did not find any benefit of VED use in the preservation of stretched penile length. Most patients had penile shortening at 1 month postoperatively; then, the penile length slowly regained regardless of additional intervention. Temporary penile shortening may result from the surgical process itself and does not occur from erectile dysfunction. Kadono et al. have shown that the stretched penile length was shortest at 10 d after radical prostatectomy and gradually recovered thereafter. Based on their magnetic resonance imaging study, penile shortening resulted from the mobilization of the proximal urethra into the pelvis during urethrovesical anastomosis. At 12 months postoperatively, the membranous urethra spontaneously returned to the original position, and the penis resumed to its preoperative length.
Preservation of penile girth with VED was strongly supported by our study. At the 4-month and 7-month visits, the mean midshaft circumference was significantly higher in the study group than the control group. A prospective study from Raina et al. similarly demonstrated that patients in the VED group were more satisfied with their penile circumference than patients in the control group. Repetitive distension of corporal sinusoid from VED-induced erection may inhibit the apoptosis process and prevent cavernosal tissue fibrosis, which leads to penile circumference shrinkage.
In summary, we have demonstrated the benefits of early VED application in patients undergoing nerve-sparing robotic-assisted radical prostatectomy. However, some study limitations should be addressed. Although designed prospectively with randomized groups and sample size calculation, the study was performed in patients from a single institution with a relatively small sample size. The occurrence of three patients in the study group not following the VED protocol complicated the statistical analysis and compromised the study reliability. Moreover, we did not measure patient or spouse satisfaction with sexual activity, which may offer more contextual outcomes. Moreover, the follow-up period of 7 months might be relatively short, and the persistence of clinical benefits is unknown. Nevertheless, the benefits derived from early VED use are promising, and it should be integrated as an option for penile rehabilitation following radical prostatectomy.
| Conclusion|| |
Following nerve-sparing robotic-assisted radical prostatectomy, early penile rehabilitation with daily VED use significantly improved IIEF-5 score and better preserved penile circumference but did not affect penile length. A larger-scale multi-institutional study is required to validate these findings.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5]