to penetrate, rigidity (from both the patient and

partner perspective) and SHIM scores. Seventy-

seven percent of patients initiated on combination

therapy and are the basis for comparative assess-

ment. All these domains experienced a 20–40%

increase in satisfaction with the addition of silde-

nafil. One critical limitation when comparing the

two group in this study is that these patients were

offered a PDE-5 inhibitor only when dissatisfied

with their VED alone, thus creating an adverse

selection bias for the control group in this subgroup

analysis. However, because almost 50% of patients

who initiated a VED reported dissatisfaction early

on, combination therapy was used in a large fraction

of the overall sample. These results suggest that the

VED may have a complementary role in EP and we

utilize it in our program for this reason.

Consistent with our philosophy on multi-modal-

ity therapy, the VED offers a non-invasive means of

achieving enhanced penile oxygenation without the

exclusion of other treatments. Additionally, it is

the most cost-effective therapy given the absent

marginal cost of usage and the ability to immedi-

ately achieve, for some, an erection sufficient for

sexual function almost immediately. While we do

not utilize this therapy alone, it offers a practical

and supportive complement to the previously

described pharmacotherapeutic regimen.

Intracavernosal injections

Among the most established strategies for producing

an erection in a patient with ED is ICI. As has been

discussed, Montorsi

et al

introduced alprostadil

ICI therapy in post-RP patients in a 1997 study that

altered the way clinicians managed post-RP patients.

Patients who used penile injections three times per

week for 12 weeks after RP were 3.5 times more

likely to have erections sufficient for erectile func-

tion. Although this study changed the way patients

are managed after RP, there are several important

limitations for inclusion and assessment, especially

because ED therapy was in its infancy and validated

assessment tools did not exist. Additionally, con-

founders for post-RP ED (for example NS) were not

well described and surgical techniques have since

evolved with the introduction of advanced laparo-

scopic and robotic techniques.

Advances in the physiologic awareness of penile

blood flow dynamics has prompted a change from

alprostadil-based ICI to trimix, a mixture of papa-

verine (30 mg ml

–1

), phentolamine (1 mg ml

–1

) and

PGE1 (10 mg ml

–1

). This combination of therapies is

typically used for ICI therapy, as it is inexpensive

and highly effective.

Mulhall

et al

conducted a non-randomized

study to assess the value of erectogenic pharma-

cotherapy on medication assisted and unassisted

erections

after

RP.

Patients

were

required

commit to a 12-month protocol premised on PDE-5

inhibitors with subsequent transition to ICI for non-

responders. Their results were compared with

patients who did not enroll in the formal protocol.

Seventy-seven percent of protocol patients required

ICI. Results at 18 months suggested substantial

improvements for the protocol group (for example

77% using ICI and 23% using a PDE-5 inhibitors

three times per week) versus the control with

respect to (1) the recovery of spontaneous erections

(52% versus 19%), (2) response to sildenafil (64%

versus 24%) and (3) response to ICI (95% versus

76%). This suggests that, for non-responders to

PDE-5 inhibitors, ICI is valuable in restoring the

ability to recover medication-assisted erectile func-

tion in almost all patients. An important limitation

to this study is that recruitment into the treatment

group was voluntary and the results may be

confounded by selection bias toward patients more

likely to be compliant with EP, who had greater pre-

RP sexual function, or were more likely to recover

natural erectile function for other reasons.

While ICI is clearly a pillar of any effective EP

program, clinicians should aggressively assess com-

pliance since documented compliance rates have

been less than desirable.

This will maximize the

opportunity for clinically desirable outcomes. In our

program, ICI is used for non-responsive patients or

those desiring to switch to this modality of therapy

in lieu of intrauretheral alprostadil suppositories.

The documented efficacy and immediacy of this

therapy are attractive, although it is not introduced

too early in the course of therapy because of

psychosexual concerns associated with self-admi-

nistered penile injections.

Testosterone replacement

In order to ensure effective recovery of erectile

function after RP, it is clear the penile tissue health

is a critical factor to both enable natural erectile

function and support the mechanisms of some of the

aforementioned agents. As has been previously

discussed, the nitric oxide pathway is an essential

signal driving erectile function by promoting penile

blood flow. An elegant animal model used by Marin

et al

demonstrated the role of testosterone in

supporting the function of nitric oxide synthase:

normal function was restored in castrated rates only

after testosterone replacement. Other studies have

shown a direct correlation between testosterone

and PDE-5 levels, suggesting that testosterone is

involved in overall penile smooth muscle home-

ostasis.

That is, testosterone regulates nitric oxide

and PDE-5 in corporal smooth muscle. Perhaps, this

balance is important to erectile function or the

general health of the penile tissues.

Androgen deprivation has also been shown to

promote adipocyte accumulation in the cavernosal

tissues.

Traish

et al.

performed a simple and elegant

experiment with control and orchiectomized rabbits.

Review and treatment protocol: erectile preservation for RP patients

DJ Moskovic

et al

186

International Journal of Impotence Research