Evening star., 1952-02-06
New Kind of Painless
Surgery Is Described
SpinoI Cords and Bruins
Of Animals Operated On
By Thonaos r. Henry

Scalpels Of uItrasound may be used
in q new kind Of painless and bloodless
surgery Of the central nervous system
possibly Of the brain.
This has Just been reported 10 the
American Association for the Advance
ment Of Science by Q cooperating
group from the University Of Chicago.
the University Of Illinois and an Illinois
State mental hospital.
Work thus far has been confined 70
animals. Operations have been on tho
spinal cords of frogs and rats and
on the brains Of rats. Beams Of sound
waves far above the hearing stage
it has been found. can be directed with
extreme precision against parts Of the
central nervous system.
The intensity-and hence the degree
Of destruction can be varied ut win.
Sound may be transmitted In steady
beam or in q series Of short pulses.
OF the greatest significance, according
TO the report by DR.. Patrick p. Wan
and his associates. sis the fact that
ultraSound wave lengths can be chosen
which viii injure only one kind Of
cell. The destruction can be confined
strictly to nervous tissue. leaving sur
rounding tissue such as muscle and
blood supply entirely unaffected. More.
over, the discrimination can be 30 hne
that only one Of the many types Of
nerve cells. usually inextricably mixed
together. is affected.
Complete Paralysis Produced.
Characteristic were experiments with
sound irradiation Of the lumbar section
Of the spinal cords Of frogs. whose nerve
centers control movements Of the hind
legs. When large doses Of ultraSound
are beamed against this region, COM
plete paralysis is produced as well -
complete loss of all sensation.
When the irradiated sections are ex.
amined from two to seven days after
treatment complete destruction Of an
the nerve cells is found. There also Ii
complete destruction OF supporting tis.
sue. The cord loses its normal strHe.
ture and becomes very soft. Many nerve
fibers are found apparently intact.
Blood vessels are dilated, but not broken.
In contrast to the effects Of the heavy
dosage, when only the minimum dose
required to produce complete paralysis
is used, sensation in the hind limbs re.
mains. Unparalyzed front legs react
vigorously to stimulation Of the skin
Of the hind legs. The explanation Is
that only those nerve cells concerned
in motion have been affected. Those
concerned with feeling have been left
essentially undamaged. There Is NO
damage to the blood vessels and finO
fibers In the spinal cord.
Still smaller doses produce no obvious
signs OF paralysis or SenSory change. eli.
though examination shows that certain
nerve cells have been badly damaged.
Major Problem.
"A major problem to be solved Is the
manner in which the cells are injured
or damaged. One theory Is that death
Is produced by overheating due to sound
absorption. It has been demonstrated.
however, that this would affect all types
OF cells in about the same manner. When
the sound radiation Is given in small
pulses, there Is very little increase in
temperature
The radiation Of the frog spinal cords
was through skin and flesh. With mice,
however. 1t was necessary to expose the
nerve area to be radiated, because Of the
strong absorbent effects Of flesh and
bone. Thus 1t was necessary to cutSS I
window through the skull Ia order ID
treat the brain. Here. however, the
direct surgery ended. sesE ss s.
DR.. Wall and his associates agree that
they are only at the frontier Of this
possible new type Of nerve and brain
surgery and no experiments vet have
been performed with humans.
1T now is clear" they say, "that Q
focused beam Of ultrasound may be
used to produce discrete LESSONS In the
central nervous system without destruc.
ton OF blood vessels or surrounding tis.
sues. BY careful control of the dosage
1t is possible to destroy latge cells only
and leave small cells, flbers, blood vessels
and connective tissue intact. Work Il
now in progress on the production Of
such selective LESSONS In order to de.
termine the anatomical and psysiologi.