Preserve Erectile Function
October 26, 98. Urologists are evaluating a new surgical
tool that can help spare some men from becoming impotent after surgery
for localized prostate cancer. The aim is to enhance and improve existing
The new tool aids surgeons in pinpointing
the microscopic nerves around the prostate that control sexual function,
so that they can avoid damaging these nerves during prostate removal,
said James Brooks, MD, an assistant professor of urology who is participating
in a national, multi-center study of the device.
"It's a useful tool to help us locate
those nerves and decrease the side effects of the operation. I think it
has great potential for decreasing impotence after radical prostatectomy
[prostate removal]," said Brooks, who practices with the Stanford
Urology Clinic, part of UCSF Stanford Health Care.
The device, approved in the USA a year ago
by the Food and Drug Administration, works by delivering a low-level electrical
stimulus to the nerves around the prostate and then measuring the erection
response. Through this process, the device helps produce a map of these
critical nerves, which are invisible to the naked eye, so that doctors
can navigate around them during surgery.
By simplifying an otherwise challenging
surgical procedure, the new tool ultimately could make nerve-sparing surgeries
much more widely available to prostate cancer patients, Brooks said. "Doctors
will be able to figure out where the nerves are, map them out and save
them," he said. "So I think this will be a boon to surgery."
Men with cancers that have spread beyond
the prostate are not candidates for nerve-sparing procedures, he noted.
Brooks is currently the only physician in Northern California who is using
the new device, which is being evaluated on a large scale at 21 medical
centers across the country. The device, called the CaverMap Surgical Aid,
is made by UroMed, a biomedical company in Needham, Mass.
The field of prostate surgery took a major leap forward in 1982, when
Patrick Walsh, MD, a urologic surgeon at Johns Hopkins Medical Center
in Baltimore, discovered that the nerves controlling erections do not
pass through the prostate, as previously thought, but are instead situated
alongside the prostate. By 1984, Walsh had developed a new technique —
nerve-sparing radical prostatectomy — that enabled him to preserve sexual
function in a percentage of his prostate cancer patients.
Results vary — while many urologists now
use nerve-sparing procedures, the results vary widely depending upon the
skill of the surgeon, the age of the patient and other factors, according
to published reports. In studies of patients undergoing such procedures,
reported rates of success in preserving sexual function have ranged from
11 to 86 percent.
A recent study from the University of Toronto
claims that with use of the CaverMap Surgical Aid, doctors may get consistently
good results in nerve preservation. In the study, described in the October
1998 issue of the GOLD Journal of Urology, Toronto researchers say they
preserved potency in 16 out of 17 men.
The device consists of a white surgical wand with a flexible tip that
delivers an electrical stimulus of up to 20 milliamps to the tissue around
the prostate. A separate, fluid-filled ring that is placed around the
penis can detect even the slightest erectile swelling in response to the
stimulus. The physician typically begins locating the critical nerves
by placing the tip of the wand at the end of the prostate, then moving
it to the middle and finally to the base of the organ. This effectively
produces a map of the key nerves involved in erectile function, Brooks
said. The patient, under general anesthetic, feels nothing, he said.
After the prostate has been removed, the
physician can retest the nerves to confirm that they have been spared,
Brooks said. Most men take months to regain erectile function after any
prostate surgery because of the trauma to the region, he noted. Use of
the nerve-finding device adds about an hour to the standard surgical procedure,
for a total of about three hours, Brooks said. Studies by others have
shown that cure rates for localized prostate cancer are the same whether
doctors perform a traditional surgery or use the nerve-sparing approach,
1, 1998. ModifiedDecember 26, 1998
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