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
), phentolamine (1 mg ml
) and
PGE1 (10 mg ml
). This combination of therapies is
typically used for ICI therapy, as it is inexpensive
and highly effective.
et al
conducted a non-randomized
study to assess the value of erectogenic pharma-
cotherapy on medication assisted and unassisted
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-
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
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
International Journal of Impotence Research