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UTERINE HEALING AFTER CESAREAN SECTION IN GOATS

by

Raj Pal Singh Tyagi

AN ABSTRACT

Submitted to the College of Veterinary Medicine.
Michigan State University of Agriculture and
Applied Science in partial fulfillment of
the requirements for the degree of

MASTER OF SCIENCE
Department of Surgery and Medicine

1959

/ I ,' ' ' , ) // /
. I/ / / ,/// . I’ ,4, ’ - -—\__\
Approved /: 54’_ *;79/ s’; {171“ /.

2
RAJ PAL SINGH TYAGI ABSTRACT

This project was performed to study the
healing process of uterine wounds following Cesarean
section in goats. The following factors affecting
healing were studied:

A. Time necessary for healing.

B. Suture materials.

C. Suture technique.

Cesarean sections were performed on eight
goats producing eighteen uterine incisions. In one
goat, the two uterine incisions were sutured with
number 50 nylon using a single row of simple . _ _
interrupted stitches, and a single row of continuous
lock-stitches respectively. The remaining uterine
incisions were sutured with either 00 catgut or
nylon using a double row of continuous lock-
stitches, or two rows of simple interrupted
stitches. A

Biopsies were performed at intervals fol-
lowing the Cesarean sections and macroscOpic and
microscopic observations made.

. The gross study of scars showed satis-
factory healing in most cases. In two, sutured
with catgut, adhesions to other organs were found

at the site of the previous incision.

3
RAJ PAL SINGH TYAGI ABSTRACT

Microscopically, it was shown that healing
had taken place by scar tissue formation.' Eibroe‘
blastic proliferation was evident in all cases and
could be demonstrated from 1h to 27 days post-
Operatively. In some cases, healing was so
complete that the line of incision could not be
followed through the sections. However, a pre- .
ponderance of fibrous tissue denoted the probable
site of the incision. No smooth muscle regeneration
could be observed.

Considerable differences were found in the
tissue reaction during healing with the use of
different suture materials. With catgut, there
was severe reaction around the sutures in four cases
with adhesions to other organs in two. No such
reactions were found with nylon.

In this study, both interrupted and
continuous stitches showed good results. The
continuous lock-stitch was faster, therefore, it
was preferred. In one goat, a single row of
simple interruptedlstitChes of numbercv . w? w“

50 nylon was used to close one of the wounds.
These sutures gave way, leaving a gap of one

centimeter which was revealed at the time of

h
RAJ PAL SINGH TYAGI ABSTRACT

.ovmsmn
post-mortem examination. From this observation, it
was concluded that a single layer of simple in-
terrupted sutures did not produce a safe closure.

Infection arxi adhesions to other organs were
considered to be important factors in the production

of an imperfect scar.

UTERINE HEALING AFTER CESAREAN SECTION IN GOATS

by

Raj Pal Singh Tyagi

A THESIS

Submitted to the College of Veterinary Medicine
Michigan State University of Agriculture and
Applied Science in partial fulfillment of
the requirements for the degree of

MASTER OF SCIENCE

Department of Surgery and Medicine

1959

ACKNOWLEDGMENTS

With sincerity and deep appreciation, the
author wishes to thank Dr. wm. V. Lumb, Associate
Professor, Department of Surgery and Medicine,_for
his inspirational guidance and unfailing interest
during this project, and for his constant help in
preparation of this manuscript.

He is deeply indebted to Dr. W. O. Brinker,
Professor and Head of the Department of Surgery and
Medicine for facilities and equipment offered in
carrying out this research.

Thanks are due to the faculty and staff of
the Surgery and Medicine Department and others who
have been helpful in various ways.

Thanks are also extended to Dr. J. C. Leshock

for his precious help and assistance.

TABLE OF CONTENTS

CHAPTER PAGE
I. Introduction. . . . . . . . . I
II. Review of the Literature. . . . . 3
A. Experimental Studies. . . . . 3

B. Closure Technique. . . . . . 12
C. Suture Materials . . . . . . 24

III. Materials and Methods. . . . . . 28
IV. ReSUlts e o o o o e o e e o 32

A. General Considerations . . . . 32
B. Studies of Individual Cases . . #3

V. Discussion . . . . . . . . . 54

A. Operative Technique . . . . . 5h
B. Uterine Healing After

Cesarean Section. . . . . . 57
C. Suturing Technique . . . . . 61
D. Suture Materials . . . . . . 63

VI. Summary and Conclusions . . . . . 67

Bibliography. . . . . . . . . 69

Figure
Figure
Figure
Figure
Figure

Figure

OUT-PWNH

TABLE OF

PLATES

PAGE
38
38
40
#0
A2
A2

CHAPTER I
INTRODUCTION

In the last decade, due to the great im-
provements in anesthetic and surgical techniques,
Cesarean section has become an established stand-
ard and important operation of veterinary
obstetrical surgery. Not only must the patient
and offspring survive the Operation, but also the
patient must be left in such a condition that it
may give spontaneous birth after a subsequent
pregnancy. In human obstetrics, unless the preg-
nancy for which the first Operation was done is to
be the last, each succeeding pregnancy means
additional danger to the mother. This has been
studied in great detail. The condition of the
healed uterus after Cesarean was found to be an
important factor in deciding the safety of a
future pregnancy.

Wound healing in the uterine wall following
Cesarean section is in some ways unique. The
incision involves the wall of the organ which is
largely composed of smooth muscles and a variable

amount of connective tissue. There are mechanical

factors which are not encountered in association
with wounds of other organs. Following the
extraction of the foetus, but almost before re-
approximation of the edges, contraction of the
uterus begins. In a few days, the uterine body and
the incision will be reduced to less than one half
of its previous size.

The process of healing may be disturbed by
several factors, such as imprOper suturing, inter-
position of the endometrium and hormonal activity
of the uterus. Post-partum infection, with its
inflammatory reaction and prolonged exudative phase,
may result in delayed.healing.

In Spite of the existing wealth of literature
dealing with the problems of wound healing, most of
the studies have dealt only with skin wounds. The
repair of wounds of hollow viscera, especially the
uterus, has by comparison received very little
attention. Most study has been devoted to the scars
that follow Cesarean sections in human medicine. So
far, very little study has been done on the scar that
results from Cesarean section in animals and no work
has been reported on the goat.

Due to the lack of information in the literature
this project was performed to study the process of
healing of uterine wounds following hysterotomies in

the goat.

CHAPTER II
REVIEW OF THE LITERATURE

The literature concerning uterine closure
and wound healing in man after Cesareans is rather
voluminous. On the other hand, the veterinary
literature seems to be lacking in this field. This
review of literature is presented in three sections:

A. Experimental studies.

B. Closure technique.

C. Suture materials.

A. Experimental Studies

The fundamental question in studies of uterine
healing usually revolves around the behavior of the
uterine scar in subsequent pregnancies; whether it
shall prove adequately firm to tolerate the dis-
tention of the uterus as pregnancy advances and to
withstand the stress of labor itself. For the
past fifty years, several authors have been con-
cerned with the anatomical study of the uterine
scar. This seems to be due to the fact that the
strength of the scar is intimately dependent upon
the histology of wound healing in.the uterus and

A

the location of the incision. There still appears to
be considerable controversy as to the exact nature of
the reparative processes taking place in healing of
the uterine incision.

Hess, Pedowitz, Schwartz and Randall (19, 33,
37) supported the theory that "Once a Cesarean
always a Cesarean" because most of the ruptures
occurred through the site of previous incision.
Williams (50) on the other hand believed this was
erroneous. In a detailed study of uteri which had
been subjected to one or more Cesarean sections, he
noted that the old scar was invisible in most instances
or could be identified at most by the presence of
shallow vertical depressions over the external and
internal surfaces of the anterior uterine wall. This
observation has been confirmed again by Audebert.and
Holland and Losee (2, 21, 25).

Mason and Williams (29) made an experimental
study of the strength of the uterine scar of pregnant
guinea pigs. These authors did no histological work,
but merely tested the strength of the scar by dis-
tending the uterine muscles, including the scar, by
attadiing weights. As the weights were increased,
the strip ruptured and.rupture always took place

outside the line of incision. Seven experiments

were carried out from 7 to 10 weeks after the
operation. By these experiments, they proved that
the tissue gave way not at the scar, but through
normal muscle fibers. From this study, they con-
cluded that a carefully sutured and well united
scar would stand any strain which could be endured
by the uterine muscle.

Phaneuf (3A) was unable to identify the
cicatrix as such in forty-one repeated lower seg-
ment Cesarean sections. Whereas, Fuchs (1h) found
it impossible to visualize the scar in thirty-three
of forty-six cases upon which he performed a second
cervical hysterotomy. Corroboratory observations
have been made by Delee and Green and Wetterwald
(11, 1.8).

The literature on the reparative process is
also divided into two schools of thought. Baun-
funwald, Shanta and Braun cited by Audebert (2) re-
ported canplete muscle regeneration in the scar
following a Cesarean section. More significant was
Williams' (50) reiteration that microsc0pic
examination of tissue removed from the site of
incision revealed complete absence of fibrous tissue
in the uterine wall. This demonstrated that the

uterus, just as all other organs containing no

striated muscle, heals by complete regeneration of
muscle fibers and not by fibroblastic reSponse.
Audebert, Losee and Williams (2, 25, 51) stated
that in those cases where there was perfect co-
aptation of the incised tissues, where the various
layers were not separated by blood clot or serum,
and where there was no infection, the incision
healed by complete muscular regeneration in 80 to
90 percent of the cases.

Losee (25) in describing his impression of
early healing, stated that in the clean wound after
incision, leucocytes, red blood cells, fibrin and
later young connective tissue cells separated the
surfaces. These afterwards were obliterated and
eventually the muscle and.fibrous strands
separating the bundles assumed the relationship
normally observed in other areas of the postpartum
uterus. Other than thickened peritoneum, there was
no scar tissue observed macrosc0pically or
microscopically in the line of former incision when
exmnined at a subsequent Cesarean Operation, pro-
vided healing occurred under normal conditions.

On the other hand, Couvelaire (8) doubted
that the reparative processes could occur without

fibrous tissue formation. Fruhinsholz, Lauvray

and Nicoletti cited by Hindman (20) followed the
same'thought.

Siegel (AA) in his experimental study used
four pregnant and four non-pregnant dogs. A
minimum of four incisions were made in the uterus
of each animal so that comparisons were made between
16 sites of wound healing in the pregnant and non-
pregnant uteri. He stated that the scars of the
non-pregnant resembled those of the pregnant uteri
except in the degree of scarring. The scars in the
non-pregnant uteri had much less connective tissue
and were thinner. Scars of the pregnant uteri were
characterized by rich cellular stroma and large
amounts of connective tissue. This abundance was
thought to be due to pronounced vascularity re-
sulting in the formation of large numbers of
fibroblasts or proliferation of the interstitial
connective tissue which increased during pregnancy.
Finally, he came to the conclusion that the
connective tissue formation, after incision into
the pregnant uterus, was abundant and greater than
in the non-pregnant uterus.

Couvelaire (8) described the process of early
healing in the human uterus. He stated that the
cicatrix in the uterine muscle always left a con-

junctive scar. The two layers of the wound were

united by a band of fibrin. In two cases, at
autOpsy five days after operation, a band of fibrin
was found to close the substratum of the con-
junctive framework, which served as the basis of
union between the various muscle bundles.

Further, he reported that in Spite of the
constant contraction and relaxation.of the uterus,
if infection was absent and the sutures had been so
laid that the edges of the incision remained ap-
proximated, firm union almost invariably resulted.
On the other hand, if there was necrosis due to
infection, or if the sutures tore through leaving
a gaping wound, there was an ingrowth of endo-
metrium which involved almost the entire thickness
of the wound. Such a scar, when seen in a sub-
sequent pregnancy, was made up almost entirely Of
decidua and peritoneum, and its gross appearance in
the unopened distended uterus was characteristic.
Instead of the vertical shallow depression seen in
the most perfectly healed scars, it was represented
by a glistening translucent band of tissue which
bulged outward beyond the general surface. After
the uterus had been emptied, hardened and cut in
cross-section, the scar was marked by very deep
depressions on both the outer and inner surfaces.

Lauvray, cited by Audebert (2), stated that

in the early healing, the lips of the wound had
serous effusion which brought them together. The
fibrin of this exudate was deposited in such a
manner that its filaments fixed themselves to the
divided muscle bundles and connective tissue and a
framework for the union was thus formed. This
framework became the substratum of the new cell
formation and the future scar tissue was outlined.
Finally, there remained between the two lips of the
Old wound a sclerous tissue which lost the prOperty
of the uterine tissue.

Hess (19) reported in his experimental study
the character Of healing in three post Cesarean
wounds of the human uterus. In all cases, micro-
SCOpic sections revealed a preponderance of connective
tissue in the scars, although in some instances
this was interspersed with varying amounts of smooth
muscle fibers. He came to the conclusion that in at
least two Species (rabbit and guinea pig), the
initial reparative process of the uterine wound was
one of fibrOplasia. There was lesseevidence of
participation of smooth muscle fibers. Examination
of microsc0pic sections of Cesarean scars indicated
that healing involved mainly fibrous tissue, parti-
cularly in lower segment incisions. In wounds

involving the upper uterine segment, smooth muscle

10
fibers interSpersed within connective tissue were
more abundant. The character of the scar was
altered by several factors. Infection with its
inflammatory reaction and prolonged exudative phase
resulted in defective healing. The common 'wtwc'
association of a history of a febrile postOperative
course with wound disruption suggested a weaker
scar. In some instances of secondary healing, in-
fection was followed by a denser scar associated
with firm adhesions which made subsequent section
technically difficult.

Schwarz and Paddock (40) appeared to have
settled the issue in their exhaustive histological
study of the Cesarean scar in the human uterus.

They clearly demonstrated the laying down Of fibrin
and fibroblasts along the line of incision in the
early process of healing, and concluded that muscle
regeneration played no important role in the healing
of the scar, and that fibroblastic proliferation was
practically normal. These observations were followed
by a series of experiments on the uteri Of pregnant
guinea pigs at term. This work also showed that the
process of healing was by scar tissue formation. In
the early stages, the marked development of fibro-
blasts could be seen much like the limbs of a tree.

As early as twelve days, in ordinary hematoxylin

11
and eosin sections, it was difficult to demonstrate
the line of incision, because of the intimate
intermingling Of cut muscle edges with fibroblastic
proliferation.

In another study on a series of uteri from
pregnant rabbits, they demonstrated the pro-
liferation of the fibroblasts along the line of
incision entering the interstices between the
adjacent muscle bundles. AS the scar contracted,
this became less perceptible and it was difficult
to demonstrate the line of incision with ordinary
stains after a period of two weeks. It was this
marked shrinking of the newly developed connective
tissue and its branching proliferation along the
muscle fasciculae that made the Cesarean scar so
frequently invisible at subsequent Operations. This
study was done by Schwartz and Paddock (LI).

In 1957, Cheli (7) studied the healing pro-
cesses of cattle, sheep and bitch uteri which were
hysterotomized at different stages of pregnancy.

He concluded that myometrium reacted to the
operative attack by formation of cicatricial
tissue. The cicatrix had no negative influence
whatever on the reproductive activity of the
subjects which had been Operated or on their

capacity to carry subsequent pregnancies.

12
B. Closure Technique

From the above information, it seems that the
technique of closing the uterine wall is a decisive
factor in the resultant healing process of the
wound.

The history Of uterine closure after Cesarean
section may be said to extend over five periods: the
first lasting from the earliest times to the begin-
ning of the sixteenth century; the second extending
from the year 1500 to 1876; the third beginning with
the introduction by Porro of amputation of the body
Of the uterus and suture of the cervix in the
laparotomy wound} the fourth, extending from 1882
to 1907, following the description by Sanger of
an accurate technique for suturing the uterine
incision, and the fifth beginning in 1907 when
Frank devised the extraperitoneal technique.

Porro and William (35) stated that the first
authentic Cesarean section was done in 1610 by
Trautman of Wittenberg. Following this, it was
occasionally performed until it became temporarily
eclipsed by symphysiotomy in 1777. It was then
taken up again after the latter operation had
fallen into disrepute. During this period, the
uterus was simply incised and the child extracted.

The uterine walls were not sutured, the contraction

and retraction of the organ being relied upon to
check hemorrhage.

According to the same reference, sutures were
first employed by Lebas in 1769, but did not come
into general use until after the appearance of
Sanger's report (39) published in 1882. Sanger
revolutionized Cesarean section by insisting upon
the necessity for suturing the uterine incision.

He advocated the use Of Lembert's intestinal suture
for cloSure of the uterus following hysterotomy and
completely altered the prognosis of Cesarean Section
in humans. .

Hindman (20) in his review of the literature
from 1882 to 1938 discussed a total of 208 ruptures
of the classical scar in subsequent pregnancies.
The incidence of rupture following classical
sections varied from two percent (Audebert (21))
to six percent (Kerr (23)) with a generally ac-
cepted average of four percent. Holland (21) in
his extensive follow up of more than a thousand
hysterotomies, demonstrated an incidence of 3.6
percent. A recent survey by McDowells, cited by
Hindman (20), of 3,300 classical Cesarean sections
disclosed that 50 (1.5 percent) had undergone
spontaneous rupture in subsequent pregnancies with

but a single death.

14

Spalding (LE) observed that suturing the
uterus to prevent death from hemorrhage was followed
so frequently by peritonitis that Jorg in 1806,
suggested a method of extraperitoneal Cesarean
section which was successfully performed by Ritgen
in 1821. Repeated Cesarean section was rarely
successful in prewantiseptic days, because there
were extensive adhesions to the wall Of the peri»
toneal cavity.

This stimulated Porro and Williams (35) in
1876, to devise the Operation for removing the
uterus and suturing the cervix into the laparotomy
wound. While the Porro operation greatly reduced
the mortality from Cesarean section, removal of the
uterus was considered to be too radical to permit
any marked increase in the list of indications for
Cesarean section.

When Sanger (39) in 1882 described his well
known conservative operation, the immediate results
were found to be so good in regard to foetal and
maternal mortality that the original small list of
indications for Cesarean section was greatly inn
creased. Sanger stated that rupture rarely occurred
after his Operation, and when it had occurred, it
was because of poor technique on the part of the

operator.

15

In 1922, Gamble (15) mentioned that hurried
closure of the uterine incision without due care
in accurately approximating the cut surfaces, the
placing of the suture too widely apart, and the
inclusion of the decidua in the line of sutures may
all be factors in producing an imperfect scar. In
his clinic, the incision was closed with two layers
of catgut, the first consisting of deep buried
interrupted sutures placed at intervals of about
one centimeter, while the second consisted of
superficial running sutures, which brought together'
the serosal edges. If, after the first layer of
sutures had been placed, there was still con-
siderable gaping of the muscularis, additional
continuous buried sutures were used. The decidua
was avoided, since any bits of it inverted into
the wound might proliferate and develop into areas
of unusual friability.

Davis (9) placed much emphasis On suturing
and was of the Opinion that the secret of pre-
venting rupture lay in suturing the uterine
incision correctly. Firstly, the stitches should
not be too tightly tied. Secondly, the catgut
should be twenty to forty day chromic catgut, other-
lwiSe absorption would be too rapid. Finally the

sutures should be so applied that there are no

16
dead spaces. He stated it was a mistake to apply
continuous sutures for suturing the uterine wall
because they will loosen during the time of re-
traction Of the uterus.

Williams (50) followed the technique of
suturing the uterus in two layers, the first layer
consisted of interrupted sutures going through the
greater part of the uterine muscle, but not coming
to the peritoneal surface. After the knots were
tied and cut, they were buried by means of a
second row of continuous sutures which brought
together the superficial layer Of muscle and
peritoneum. Following this technique, he had only
a single rupture in fifty pregnancies following
previous sections, and that occurred in a woman who
was profoundly infected at the first section.

In 19A2, Potter (36) described the technique
of suturing the uterine incision by using
interrupted silk sutures. The sutures, which were
spaced one-fourth of an inch apart, were tied
sufficiently tight to hold_the parts intact with-
out blanching of tissues. Following this method,
he noted the marked absence of the usual post-
Operative bleeding which, in the two layer
technique, was a frequent occurrence. He con-

cluded that this improved method of closure not

17
only corrected the difficulties, but also prevented
strangulation of the muscle. He also Observed that
in the presence of infection of any degree, this
mode of suture permitted free and adequate drainage
into the uterine cavity.

Green and Bloom (18) in their experimental
study used interrupted sutures in four wounds. Two
of these incisions failed to show any scarring while
the other two contained much scar tissue, but were
anatomically strong. In these four cases, no bad
scars resulted. They observed that the closure
with interrupted sutures yielded better scars than
closure with continuous sutures.

Milne (31), in five cases presented to hisfl
clinic, closed the uterine incision with a single
layer of continuous Lembert suture using number
one medium chromic catgut with a swedged~on needle.
An injection of two to three cubic centimeters Of
posterior pituitary extract was used intramuscularly
to accelerate uterine involution. The incision
through the peritoneum, abdominal musculature and
aponeurotic layers was closed by a Single layer of
number two catgut using continuous or interrupted
horizontal mattress sutures.

In 1953, Riley £38) mentioned the technique

of suturing the uterus in ewes which he used in

l8

clinics. He emphasized the use of an anchoring
suture to hold the uterus into the incision as it was
sutured. A single strand of number two chromic cat-
gut was used to close the uterine incision. An
anchoring tie was made approximately one inch from
the lower extremity of the uterine incision,
leaving the free end of catgut protruding about two
inches from the surgeon?s knot. Then a series Of
continuous right angle Cushing sutures were used
dorsally up the length of the incision to a point
about one inch beyond the proximal extremity of
the incision. Without tying, the suturing was
reversed, using the same stitch, and tied to the
projecting piece cf catgut left when the initial
anchor suture was made. Thus, the first row of
sutures closed the uterine incision, inverting the
incision lips and bringing serosa to serosa, and
the second layer effectively buried the first layer.
He observed that closure of the uterine in-
cision should commence at the anterior or distal
portion of the uterine incision since marked
involution occurred quite rapidly in many cases.
Therefore, it was easier for the Operator to
finish his suturing and tying where he could see
and use his hands more freely.

Ellis (13) performed Cesarean section on 69

l9

ewes under local anesthesia using thirty cubic centi~
meters of five percent procaine hydrochloride for
infiltration. The lower left flank, lower right
flank and the midline approaches were tried and the
latter site was found to be the most satisfactory
one. It was observed that involution of the uterus
was rapid in ewes following removal of the fetuses
and consequently the incision in the cornua somew
times became out Of apposition with the abdominal
incision. For this reason, the incision was kept
as far back as the udder allowed. Continuous
single Lembert sutures with number one and number
two catgut were used for suturing the uterus,
while the abdominal would was sutured with inter=
rupted sutures of nylon.

Arthur, Gould and Mackinnon and Bayliss
(l, 16, 27) followed the same technique as described
by Ellis and Milne.

Parkinson (32) described the operative
technique in sheep and cattle. In sheep, he
sutured the uterus using a continuous Lembert type
of stitch with fine catgut. Abdominal muscles and
the peritoneum were closed together, using six or
seven mattress type sutures Of medium catgut. The
skin was closed the same way. In cases where the

uterine contents were found to be septic, oilswax

20

penicillin was inserted between each layer of sutures.

In cattle, once the calf,had been delivered,
the Opposite edges of the uterine wall were picked
up with forceps so that the foetal membranes could
fall back into the uterus. With an assistant still
holding the forceps and applying slight traction to
keep the empty horn exterior to the abdomen, the
uterus was closed with eight or nine interrupted
Lembert type stitches of catgut., These were
further reinforced with a continuous Lembert
stitch, again using catgut. This was found to be,
especially necessary where a dead and decomposing
foetus had been delivered. After the calf had
been removed, contraction Of the uterus was im-
pressive. The incision was observed to contract
‘ to half its normal length before the second row
of stitches had been inserted. After cleansing,
the organ was replaced in the abdomen. The peri-
toneum and internal Oblique muscle were then
picked up together and sutured with cOarse catgut
using interrupted Halsted stitches. A special
technique was used for closing the peritoneum and
muscle in which the sutures were placed at least
half an inch away from the cut edges. This was
done to keep the lip projecting externally so it
could be picked up and incorporated in the next

_ 21
layer of stitches. This strengthened the wound and
obliterated the dead Space between the different
layers of muscles. The next layer which was sutured
consisted of external muscle, connective tissue and
the lip projecting from the internal oblique muscle.
Interrupted mattress type stitches of catgut were
used. Oilawax penicillin was applied along the line
of stitches after the layers of sutures were com-
pleted. This method was recommended for its rapid
healing and neatness of finish.

In 1956, Messervy 23 g1, (30), in reporting
the advantages of performing Cesarean sections
through the left flank by vertical incision in the
standing position, mentioned the following:

1. There was reduced shock because of less

handling.

2. There was no omentum as it would be
present in the right flank.

3. Wounds were found to be easier to suture
and healed quicker perhaps due to the
fact that the incision was through.
muscles. The incision through the
aponeurosis lower down in the flank
parallel to the milk vein was found
slower to heal.

He sutured the uterus with a continuous

22

Lembert stitch of number four catgut on a straight
or curved atraumatic needle. At least one to one
and onewhalf inches of the cut edges were inverted.
He advised that suturing commence from the pos~
terior extremity of the wound as the uterus might
retract into the abdominal cavity and difficulty
might otherwise be experienced in the insertion of
sutures. Owing to rapid involution and tendency
of sutures to loosen, there was less likelihood of
strangulation of tissue and, therefore, sutures
could be tied snugly. In closure of the incision,
special care was taken to ensure that portions of
foetal membranes were not interposed between wound
edges as this was found to interfere with healing.

The abdominal would was closed, using eversion
stitches of number 50 nylon. Only six or seven
stitches were inserted, each being held at the edges
of the incision by rubber tubing through which the
suture material was threaded at the time of insertion.

In 1957, Lensch (2h) described the suturing
technique which he used in 8A Cesarean sections.
The uterus was closed by a running stitch with
number five catgut. He started from the cranial
end of the incision, going through the serosa and
muscularis, but avoiding the mucosa so that foetal

membranes would not be fixed to the uterine wall.

23
Protruding parts of the membranes were excised. In
the event of a living foetus, a second line Of
stitches was not applied, but in case of delayed
birth with an atonic and fragile uterus, a second
line was required. The abdominal muscles were
closed with catgut sutures with the stitches
penetrating the internal and external muscles at
the same time, thereby avoiding the formation of
cavities. The Skin was closed by "intraper-
cutaneous" sutures using nylon thread.

In 39 Operated animals, 9 were no longer used
in breeding. Thirty were served or inseminated
again with 24 becoming pregnant. One cow aborted
in the sixth month of pregnancy. Twenty-one cows
calved normally, and two required veterinary aid
due to abnormal position and size of the foetus.

In 1958, De Bois (10) reported the operative
technique of Cesarean section in 113 ewes and
listed the results achieved with this method. A
flank approach under inhalation anesthesia was
used. ,The uterus was closed by means of number 90
knotted linen using Lembert stitches. In all cases,
only one horn was incised and the foetuses from
both the horns were removed from the same incision.
The abdominal incision was also closed with knotted

suture.

2b
He could not study the fecundity of the
Operated animals as all of them had been intended
for the graziery. Only three afterwards conceived
and lambed in the normal way. Two of these animals

dropped normal lambs twice.

C. Suture Materials

Regarding suture material, Opinions are also
divided. Babcock, Gamble and Potter (3, 15, 36)
advocated the use of non-absorbable, non-irritating
suture materials as they caused less tissue reaction
and thus resulted in good healing. 0n the other
hand, Schmitz (43) obtained excellent results with
catgut and concluded that wound healing was less
dependent on the material than on the method.
Supporting this latter view was the’wtrk of Bowers,
Burns and Mengle (5) with fine 5-0 chromic catgut
suture in surgery of the gastroenteric tract, the
biliary tract, and in dura, tendon, nerve and
fascia.

In 1922, Gamble (15) mentioned that chromic
catgut had given relatively satisfactory results.
In a series of Operations, he used silkworm-gut in
a single instance, and the resulting scar was ideal.
When the uterus was removed a year later, the

sutures were still in situ, but dense adhesions

. 2 5
had developed along the entire length of the scar.
He believed this was the result of knots irritating
the surrounding tissues, and felt that when using
this material the sutures should be buried and the
superficial layer and peritoneum brought together
with catgut over them.

Holland (21) believed that chromic catgut was
absorbed more rapidly than was desirable, particu~
larly in the presence of infection. Upon analysis
of a large number of cases, he found that subse-
quent rupture occurred two and a half times more
frequently after the use of catgut than silk.
Consequently, he was of the Opinion that non-
absorbable sutures were preferable, and that
silkworm-gut fulfilled the requirement most
satisfactorily. ‘

Prusman, cited by Gamble (15), objected to
non-absorbable sutures on the ground that small
channels were formed around them. When they were
invaded by bacteria or even by endometrium,
necrosis and weakening of the scar resulted.

In 1904, Eckstein (12) indicated the ad-
vantage Of metalic sutures, and suggested the
use of thin flat bands of lead which, in addition
to being nonuabsorbable, would serve as a support

for the scar in future pregnancies.

26

Babcock (3) reported his experience of ten years
regarding the relation of wound reaction and lag in
healing to the suture. He stated that around the
catgut used in a wound closure there soon develOped
an intense polymorphonuclear infiltration within
which, close to the catgut, was a zone of tissue
necrosis. Thus, in a wound closed with catgut, the
early inflammatory and necrotic reaction so delayed
healing that the union was weakest about the seventh
day and there might be a tendency to suppuration.
He Observed that by putting only a few sutures in
the Cesarean wound the reactiorlwas reduced and
better healing resulted. In a septic field, he
found nothing to equal non—irritating metalic
sutures, which were not extruded even under
suppuration.

Bates (A) reported the following advantageous
features of fine silk:

1. Minimum wound reaction in healing.

2. Minimum infection in potentially clean

wounds.

3. Firm support of the wound throughout

its critical healing period.

He further studied the absorbability of
catgut on healthy adult dogs which were subjected
to gastroenterostomy under standard surgical

conditions. The gastroenterostomies and the

27
abdominal wounds were each closed with the suture to
be studied at intervals of 24 hours, four days, one
week, two weeks, and four weeks. The wounds were
examined grossly for the state of healing, perm
sistence of gross fragments of catgut and peritoneal
adhesions. Both the gastroenterotomy and the
abdominal wound in each case were examined micrOw
SCOpically.

He found that plain catgut excited a prompt,
violent exudative foreign body reaction which
delayed the appearance Of fibroblasts and so
delayed wound healing. Large plain catgut was
absorbed practically as fast as smaller sizes, and
any size failed to hold throughout the time wound
support was needed. Chromic catgut was associated
with a retarded and lessened exudative foreign
body reaction and with the early appearance Of
fibroblasts and early healing. Small chromic
functioned longer than very large chromic catgut.
Wound support and healing were most satisfactory

when the smallest chromic suture was employed.

CHAPTER III
MATERIALS AND METHODS

In this study, adult female pregnant goats
were used. Their weights varied from 85 to 115
pounds. Near term, they were kept in separate
stalls on ration consisting of hay and ground
dairy feed*.

Each animal was bred by artificial in-
semination and, when the usual physical signs of
approaching parturition developed, a Cesarean.
section was performed. The animal was fasted
overnight and an antiferment turcapsol** was
given orally via stomach tube, one hour before
the Operation. This was done in an attempt to
slow down the fermentation process in the rumen.
Ten minutes before the operation, a tranquilizer,

***), was

triflupromazine hydrochloride (vetame
injected intravenously at the rate of one milli~
*Okemos Elevator Co., Okemos, Michigan.

**Pitman-Moore Co. ivision of Allied Laboratories,
Inc., Indianapoiis, Indiana.

***E. R. Squibb and Sons, New Brunswick, New Jersey.

29
gram per pound of body weight as a preanesthetic.
_A trough shaped wooden table tOp was designed and
was placed on a normal size small animal Operating
table. The animal was restrained on this in left
lateral recumbenCy by tying both the front and hind
limbs with separate rOpes.

In the first case (goat 5), an ultra short
acting barbiturate, thiamylal sodium (surita1*),
provided general anesthesia, but in the rest of
the animals a paravertebral lumbar nerve block
technique was used. Ten cubic centimeters of a
two percent solution of procaine hydrochloride was
deposited on the last thoracic and first and second
lumbar nerves on the left side. In all, thirty
cubic centimeters of the solution were used. The
left paralumbar fossa was clipped and scrubbed
with liquid germicidal detergent*.. After masking
the Operative site with sterile drapes, a low
vertical six inch flank incision was made through
the skin, muscles and peritoneum midway between
the last rib and tuber-coxa. The uterus was
located and brought to the outside through the
incision. Then a five inch incision was made

into each horn, close to the body of the uterus

—_

*Parke, Davis and Co., Detroit, Michigan.

30
in all the animals, except goat 10 in which the
uterus was incised at four places.

The foetuses were immediately delivered,
dried with towels and removed to a cardboard box
fitted with light bulbs to keep them warm.

After extraction of the kids, the protruding
foetal membranes were returned to the uterine
horns. In.goat 5, the uterine incisions were
closed with size 00, medium chromic catgut by the
use of a double row of continuous lock-stitches.

In goat 10, 13 and 18, the uterine incision in one
horn was sutured with size 00, chromic catgut by
the use of a double row of continuous lock-stitches,
while a double row of interrupted sutures were used
to close the incision in the other horn. In goats
l, 2 and 21, the uterine incisions were closed with
number 50 nylon by the use of a double row of
continuous lock-stitches in one horn and a double
row of interrupted stitches in the other. In goat

3 only, a single row of continuous lock-stitches
was used in one horn and a single row of interrupted
stitches was used in the Opposite horn. In all
cases, the peritoneum and muscles of the abdominal
wall were closed with single simple interrupted

non-absorbable sutures (vetafil*) and the skin

 

*Bengen and Co., Hannover, Western Germany.

31
brought in apposition with simple interrupted sutures
of the same material. The goats were removed from
the Operating table and placed in a box stall.

The healing process of the uterine wounds was
checked after the following period of time; 3, 1h,
18, 19, 21, 26 and 27 days. At the end of the
desired number of days, the uterus was exposed
under aseptic conditions and a biOpsy was per-
formed. Surital was used to provide general
anesthesia in all cases. One inch of uterine
tissue was Obtained at the site of the scar and
fixed in ten percent formalin. After fixation,
portions of the tissue, including the healing
edges of the wound, were dehydrated and infiltrated
following the technique described by Johnson 23 51.
(22). Then the tissue was embedded in paraffin,
and cut at seven microns. Harris' hematoxylin
was used as routine stain. weigert's and Van
Geison's stains were used for the study of
elastic and collagenous tissues and muscle

fibers.

CHAPTER IV
RESULTS

A. General Considerations

Surital was used for general anesthesia in
the first animal of this series. It showed no
detrimental effect on the goat. Of the two kids,
one died one hour after birth of respiratory
failure and the other died two days later. Both
had shown some degree of depression. To overcome
this drawback in subsequent cases, a tranquilizer
(vetame) and paravertebral anesthesia were used.
This gave satisfactory anesthesia lasting for about
one and one-half hours and had no ill effect upon
the kids. This method of anesthesia also proved
useful in that the kids could be attended by the
mother immediately after the Operation.

To determine the best approach to the uterus
near the bifurcation of the horns, the mid-line and
the lower left flank approaches were tried on two
non-pregnant goats. The lower left flank approach
was found to be more satisfactory. (In the mid-line
approach, the udder was a considerable hinderance.

A five inch incision was made in the left

33
lower flank region, extending mainly in a dorso-
ventral direction. The lower part of the incision
terminated one inch above the mammary vein. An
anatomical study of this area was made and the
incision was found to pass through the following
layers:

1. Skin - Very thin and freely movable.

2. Muscle cutaneous trunci - Present through-
out the entire incision and increased in
thickness as the ventral limit of the
incision was reached.

3. Oblique muscles - Ventrally, the
incision passed through the combined
aponeurotic part of the external and
internal oblique muscles.

A. Internal sheath of the rectus abdominis
muscle which at the site consisted of
the aponeurosis of the transverse
abdominal muscle.

5. Peritoneum.

In this study, it was noted that any slight
variation in the Site of incision altered the
disposition of the muscular and aponeurotic tissues.
For instance, the incision made at the time of
biOpsy was two inches behind and dorsal to the pre-

vious incision. Consequently, at the upper

31+
extremity of the incision, muscle fibers of the
external and internal obliques were evident, but no
muscle fibers of the rectus abdominis and trans-
versalis were present.

Incision in the horn was made close to the
body of the uterus. In removing the foetuses,
emphasis was placed upon extension of either fore
or hind limbs to ensure that flexed elbows or
flexed stifles were not drawn through the uterine
incision simultaneously causing rupture. A care-
ful search of the uterus for twins or triplets was
carried out in all cases.

It was observed that involution of the
uterus was not so rapid as reported by other
authors following removal of the foetuses, and no
difficulty was encountered in suturing the
incisions of the uterine horns.

Difficulty was encountered in separating
the foetal membranes from the uterine mucosa. To
allow them to separate naturally, they were left
inside the uterus after removing the kids. The
foetal membranes were usually expelled post-
Operatively within twelve hours. However, in
some goats the retention of foetal membranes
extended up to 2A hours followed by a foetid

discharge from the vagina in one animal.

35

From the eight operated goats, nineteen kids
were delivered, twelve were living, two were
mumified and five died because of premature birth.
It was observed that of the twelve living kids a
few which were delivered prematurely had difficulty
in breathing.

During the routine postOperative care of the
goats, the temperature was recorded for three days
in all animals. Recovery was uneventful in all
except goat 3 which had a temperature of 105°F. and
died three days after operation. Goat 5 had a
temperature of 103°F. for three days and then it
returned to normal. In goat 3, 100 cubic centi-
meters of cal-dextro* were given intraperitoneally.
No medicine was given postoperatively in the re-
maining animals.

The character of healing was studied in
eighteen post-Cesarean wounds during this ex-
periment. Macroscopically at biopsy it was found
that healing was complete in all animals except
goat 3 which died three days after operation due
to uterine infection and hemorrhage from a carotid

loop. The carotid loop had been permanently

 

*Fort Dodge Laboratories, Inc., Fort Dodge, Iowa.

36
established some time previously for experimental
work by another graduate student. Although most
animals had a clear scar with no adhesions to ad-
jacent organs, goats 5 and 10 showed adhesions.

In goat 10, biopsy was made at two different
ingervals; that is 1A and 19 days postOperatively.
At the first biopsy, the wound was free of ad-
hesions, but at the second, extensive adheSions
were observed between the wall of the uterus and
omentum.

Microsc0pically, the line of incision could
be followed readily in the tissues Obtained from
goats 10 (Figures 1 and 2), 13 and 21 at 1h, 18
and 21 days after Operation respectively. But, in
other cases this could not be observed because of
complete healing. However, a preponderance of
fibrous tissue denoted the probable Site of the
incision.

Considerable differences were found in the
tissue reaction during healing with the use of
different suturing materials (Figures 3 and A).
Around the catgut sutures, a marked tissue
reaction characterized by the presence of
numerous leucocytes and blood could usually be
seen. With nylon sutures, there was very little

or no tissue reaction (Figures 5 and 6). No

Figure 1.

Figure 2.

37

‘Uterus of goat 10, 1h days postOperatively.

Two rows of continuous lock-stitches of

00 chromic catgut were used. The incision
is visible running vertically through the
center of the tissue. Large dark masses
are catgut surrounded by phagocytes.

17x.

Higher magnification of incision shown
above. Fibroblastic proliferation is
evident between the edges of the

incision. 75x.

 

 

6.

.
w,
0’

1? 9-

 

Figure 3.

Figure he

39

Uterus of goat 1, 1h days postoperatively.
Two rows Of simple interrupted stitches of
number 50 nylon were used. The incision
runs vertically through the center of the
tissue and is almost indiscernable. There
is little peritoneal reaction. The
straight line through-the tissue is an
artifact. 75X. A

Uterus of goat 21, 21 days postoperatively.
Two rows of continuous lock-Stitches of OO
chromic catgut were used. An intense
peritoneal proliferation surrounds the
catgut near the surface Of the uterus.

The line of incision cannOt be definitely
distinguished. 75x.

 

40

Figure 5.

Figure 6.

#1

Number 50 nylon in uterus 19 days post-
operatively. Note the honeycomb
appearance of the nylon and lack of

surrounding tissue reaction. 75x.

Chromic OO catgut in uterus 27 days
postoperatively. Phagocytes are
infiltrating the catgut along its

surfaces 75x0

‘L .W .I O L Iv" ‘I.Obwuk ’0 ‘

\

 

Figure 6

 

#3
evidence of smooth muscle regeneration could be

observed during this study.

B. Studies or Individual Cases

Goat 3: Uterine scar three days post-
operatively. Nylon was used to close the wounds.
A single row of interrupted stitches was used to
close the incision in one horn, and a single row of
continuous lock-stitches was used in the opposite
horn.

This animal died three days after Operation
and at post-mortem the following gross lesions
were noticed:

1. Marked post-mortem changes.

2. Pale mucous membranes.

3. Fibrinous exudate and blood tinged fluid

in.the-abdominal cavity.

A. A hole about one centimeter in diameter
in the uterine wound which was stitched
with simple interrupted stitches. The
continuous lock-stitches used in the
other horn were intact.

5. Uterus moderately distended with fluid.
Bacterial examination of the uterus
revealed the presence Of coliforms, an

enterococcus and a beta streptococcus.

1.1.
Conclusions and comments by the pathologist: "It is

my Opinion this animal died from a peritonitis due
partially to the spilling of uterine contents in the
abdominal cavity and external hemorrhage from the
area where the catheter was inserted into the
carotid artery".

Microscopic study revealed no healing of the
uterine wound and there was infection present as
evidenced by numerous bacteria and leucocytes.
Suture material was not evident anywhere in the
section. There was a wide gap between the two
edges of the incision which was filled with
fibrinous exudate. There was hemorrhage along
the line of incision. In this case, the line of
cleavage was clearly defined.

Goat l: Uterine scar 1A days post-
Operatively. Nylon was used for suturing the
wounds. There were two wounds in the uterus, one
in each horn. In one wound a double row of
interrupted nylon stitches were used, whereas: in
the other wound a double row of continuous lock-
stitches were used. 4A.gross study of the tissue
showed healing with no adhesions to other organs.

MicroscOpic examination revealed healing had
progressed well and the approximation of wound

edges along the incision line was almost perfect.

45

There was no sign of infection. Very little reaction
was seen around the edges of the wound. At places
tissue surrounding the suture material was rich
with leucocytes and cells of the reticulo-endothe-
lial system. A few giant cells could be seen
around the suture material. Where the inflammatory '
reaction surrounding the suture material was
marked, the infiltration of fibroblasts and white
blood cells was quite evident. Here the line of
incision could not be distinguished. L

Goat 2: Uterine scar 19 days post-
Operatively. Nylon was used to close the wounds.
There were two wounds in the uterus, one in each
horn. In one wound, a double row Of interrupted
stitches were used, whereas, in the other wound a
double row of continuous lock-stitches were used.

Gross examination of the scar showed healing
with no adhesions to adjacent structures. The
nylon sutures were lying very superficially in the
serosa. There was very little scarring on the
external surface of the uterus. There was good
approximation throughout the wound and histological
findings were no different than in goat 1. Very
little reaction was seen in the tissue. The reaction
around the nylon sutures was practically nil. In

the entire area of the incision, a marked

#6
proliferation Of fibrous tissue could be seen. The
line of incision could not be distinguished in the
sections.

Coat 13: Uterine scar 18 days post-
Operatively. Catgut was used to close the wounds.
There were two wounds in the uterus, one in each
horn. A double row of simple interrupted stitches
were used in one horn, whereas, in the other wound
a double row of continuous lock-stitches were
inserted.

Gross examination of the scar showed
complete healing with no adhesions to other
structures. There was a considerable amount of
scarring at the site of the incision.

MicroscOpic study revealed complete ad-
herence Of the wound edges. Scar tissue was still
in formation as evidenced by the presence of young
fibroblasts in the area of incision. There was
quite extensive reaction around the suture material
and reabsorption was still in progress. Layers
around the suture material from within outward
were as follows:

1. Central layer: Catgut giving the

appearance of a homogenous pink mass.

2. Middle layer: White blood cells and

cellular debris.

A7

3. External layer: Young fibroblasts with

blood capillaries and white blood cells
dispersed between them.
There was extensive reactiOn in the area of the
wound. The line of incision was not visible
throughout the section.

Coat 10: Uterine scars It and 19 days post-
Operatively. Catgut was used to close the wounds.
Four incisions were made in the uterus two in each
horn. In two wounds, a double row of interrupted
stitches were used, whereas, in the remaining two
wounds a double row of continuous lock-stitches
were used:

Gross examination after 14 days showed com-
plete healing with all the wounds being free from
adhesions. After 19 days, extensive omental ad-
hesions were observed at the site Of the wounds.

Microsc0pic study revealed healing had pro-
gressed well in all the tissues and no infection
was present. The line of incision could be readily
followed through the tissues taken at 1A days after
Operation, but the tissue taken 19 days after
Operation showed no incision line. Fibroblasts
could be seen along the entire wound and at some
places blood was present between the two edges of

the wound. There was a marked reaction around the

#8
catgut sutures which were present in all the tissues.

Coat 21: Uterine scar 21 days postOperatively.
There were two wounds in the uterus, one in each
horn. Nylon was used for suturing the wounds. In
one wound, a double row of simple interrupted
stitches were used, whereas, in the other hdrn a
double row of continuous lock-stitches were used.

Gross examination of the scar showed complete
healing with very little granulation tissue on the
external surface of the uterus.

MicroscOpic study revealed very little healing
at a few places along the line of incision, but
where the edges had been well approximated there was
good union between the two sides. At places red
cells were present between the two edges of the
wound. Suture material was present, but there was
no inflammatory reaction in the surrounding tissue.
Some white blood cells and young fibroblastic cells
could be seen infiltrating the suture material and
it presented the appearance of adipose tissue or of
a honey comb. The line of incision could be readily
followed in the tissue.

Goat 5: Uterine scar 26 days postOperatively.
There were two wounds in the uterus, one in each

horn. -Catgut was used to close the wounds. A

#9
double row of continuous lock-stitches were inserted
in both the horns.

Gross examination of the scar showed slight
adhesions around the catgut sutures.

Microscopic sections showed extensive tissue
reaction. The tissue was heavily infected and there
was marked increase of neutrOphils. At places,
clotted blood was also present. Damage extended
into the mucosa, involving the epithelium at a few
places. The adventitia was rich with engorged
blood vessels showing excessive inflammatory
changes.

, Coat 18: Uterine scar 27 days post-
Operatively. There were two wounds in the uterus,
one in each horn. Catgut was used for suturing the
wounds. In one horn a double row of simple inter-
rupted stitches were used, whereas, in the Opposite
horn a double row of continuous lock-stitches were
inserted.

Gross examination of the scar showed healing
with no adhesions to other organs.

Microscopic study revealed phagocytic action
in the tissue and some hemorrhage in the area of
the wound. Engorgement of the vessels was seen at
a few places. The incision line could not be

distinguished.

TABLE I‘

SUMMARY OF DATA

50

 

 

 

 

 

 

Type of stitches Number of
and number of rows days post-
Goat Suture A. Right horn Operative
Number Material B. Left horn biOpsy made
A. Single row of
simple inter-
rupted stitches.
3 Nylon 3 days
B. Continuous
lock-stitches.
A. Two rows of
simple inter-
rupted stitches.
1 Nylon 1A days
B. Two rows of
continuous
lock-stitches.
A. Two rows of
simple inter-
rupted stitches.
10 Catgut 1h days
B. Two rows of
continuous
lock-stitches.
A. Two rows of
Simple inter-
rupted stitches. ,
l3 Catgut 18 days

 

 

B. Two rows of
continuous
lock-stitches.

 

 

u

51

TABLE I
(Continued)
SUMMARY OF DATA

W

 

Goat Gross Microscopic
Number Appearance Appearance
A hole one centi- 3 NO healing. In-
meter in diameter fection present.
in the uterine in- Line of cleavage

cision. No adhesions. clearly defined.

No adhesions. No healing.
Stitches were intact.

 

NO adhesions. Complete healing.
No infection.

Very little re-
action in the tis-
1 sue. Line of in-
cision could not
be distinguished.

A

 

No adhesions. Healing in pro-

" gress. No in-
fection. Marked
. reaction around
10 sutures. Line of
incision could be
followed in the
tissue.

 

NO adhesions. Healing complete.
Extens ve reaction

' around sutures.

13 Line of incision

could be dis-

tinguished in

tissue.

 

 

 

TABLE I

(Continued)

SUMMARY OF DATA

52

 

 

Goat
Number

Suture
Material

Type of stitches
and number of rows

A.
B.

Right horn
Left horn

f

Number of
days post-
Operative
biOpsy made

 

10

Catgut

A.

Double row of
interrupted
stitches.

Double row of
continuous
lock-stitches.

19 days

 

Nylon

Two rows of
interrupted
stitches.

Two rows of
continuous
lock-stitches.

19 days

 

21

Nylon

Two rows of
simple inter-
rupted stitches.

Two rows of
continuous
lock-stitches.

21 days

 

Catgut

and B. Double
row of continuous
lock-stitches.

26 days

 

18

 

Catgut

 

Two rows of
Simple inter-
rupted stitches.

Two rows of
continuous
lock-stitches.

27 days

 

 

TABLE I

(Continued)

SUMMARY OF DATA

53

 

Goat
Number

Gross
Appearance

‘

Microscopic
Appearance

 

lO

Extensive adhesions
around the sutures
in both the wounds.

Healing complete.
Line of incision
not clearly defined.
No infection.

Marked reaction
around the sutures.

 

No adhesions.

Healing was good.
Very little reaction
in the tissue. No
reaction around the
sutures. Line of
incision could not
be distinguished.

 

21

No adhesions.

Little healing at
few places along
the line Of in-
cision. The in-
cision line could
be readily followed.
No tissue reaction.

 

Slight Adhesions.

Infection present.
Extensive tissue re-
action. Complete
healing. Incision
line could not be
distinguished.

 

18

 

No adhesions.

 

Healing complete.
Phagocytic action
in tissue and

‘lincision line could

not be distinguished.

A

 

CHAPTER V

DISCUSSION

A. Operative Technique

Ever since Sanger (39) first described the
technique of Cesarean section, the history of the
Operation has been a recital of a series of efforts
to find the most suitable point of entrance into
the uterus. Almost all operative techniques in the
veterinary field have been standardized and one or
possibly two methods are almost universally re-
cognized as the most successful. This cannot be
said Of Cesarean section. Large numbers of ’
successful cases, varying in suture techniques are
recorded.

One of the American authors cited by Lensch
(24) states, "I have carried more than 500 Cesarean
sections in standing and lying cattle, as laparo-
tomy right and left, in the lying animal in the
’median.plane, paramedian left and right according
to the position of the foetus. Each of these
methods has its drawbacks and advantages. In
obstetrical surgery, different to all other surgery,
it is most important to master every technique

55
according to the position Of the foetus. The
obstetrical patient forces the veterinarian to adapt
his method to the Special condition".

What is required is a site from which the
uterus can be readily brought into the incision and
maintained there without undue strain on the
Operator or his assistant. Unquestionably, success
depends largely upon experience and good assistants.
As to the detailed operation, it seems tO matter
little in the result whether the abdominal incision
is made in the flank region or at mid-line; whether
the uterine incision is close to the bifurcation of
the horns or away from it. Anyone able to do a
Cesarean section is generally capable of deciding
for himself the best way tO deliver a given case.

In this study, the lower left flank incision
was found much more suitable than any other site.
The peritoneum could be entered along the lower
border of the rumen. On pulling the omentum for-
ward, the uterus was immediately exposed and could
be drawn into the incision. This approach pre-
vented the escape of abdominal viscera and no
difficulty was encountered in handling the uterus.
The advantage of the left flank site is that there
is less danger Of intestinal prolapse. However,

if the rumen is nearly full, it may be difficult

56
to keep out of the way.-

It is interesting to note that in human
obstetrics there is a current tendency to favor
Spinal anesthesia for blocking pain perception.

By this method, there is minimal transplacental dif-
fusion of drug to depress fetal metabolism. Newborn
infants seldom require resuscitation after spinal
anesthesia, whereas, it is often necessary after
general anesthesia. The University of Denver
Hospital reported that fetal mortality associated
with Cesarean section was 19 percent during the first
five-year period preceeding 19A6 (46). All Of these
operations were performed under general anesthesia
administered by inhalation. During the next five
year period, 96 percent of the Cesarean sections
were performed under regional anesthesia. Fetal
mortality drOpped from 19 to 8 percent. The im~
provement was attributed largely to the use of
regional instead of general anesthesia. Comparable
data are not available in veterinary medicine, but
the similarity of other principles of anesthesiology
in man and animals justifies the assumption that

the above data for human beings may have application
to domestic animals.

In this study, general anesthesia was used

in goat 5. It had no untoward effect on the

5?
mother, but certainly had a depressing effect on the
kids. To avoid this difficulty a combination of
tranquilizer (vetame) as preanesthetic and procaine
hydrocthride as a local anesthetic was used. Fol-
lowing this technique no difficulty was encountered
in obtaining good anesthesia and no ill effects
were noticed upon the kids.

Although paravertebral lumbar anesthesia is
preferred for surgery on the region of the para-
lumbar fossa, difficulty may sometimes be en-
countered in anesthetizing excessively fat animals
because Of the obliterated anatomical landmarks.

In this study, no such difficulty was encountered

in blocking the nerves.

B. Uterine HealinggAfter Cesarean Sectiqg

The histological characteristics of the
healing wound to a large extent reflect the strength
of the scar. The type of tissue of which the
latter is composed will govern its ability to
withstand the effects of the ensuing pregnancy and
the additional strain of labor. On this subject
many differences of opinion were expressed in the
literature. A large group of Obstetricians believed
that the uterine incision healed by the formation of

scar tissue while another group firmly believed

58
that healing was entirely by the process Of muscle
regeneration. Since the assertion by Williams (50)
that union resulted from regeneration of smooth
muscles, most authors have directed their attention
to the anatomical studies of these scars. The
ability of smooth muscle fibers to undergo growth
changes and reproduce themselves has been demon-
strated by many authors (19, 21, 25).

In spite of the above statements, in this
study no smooth muscle regeneration could be
Observed. 0n the other hand, in all eight uteri
of this series microscOpic study revealed the
presence of fibroblasts along the line of incision
with the scar being composed mainly of connective
tissue. These results agreed with Schwarz' and
Paddock's findings (40, A1) which showed that
healing was the result Of proliferation of fibrous
tissue and clearly demonstrated the lying down of
fibroblasts along the incision line. Their
observation has not been contradicted. Cheli (7)
has also observed the formation of cicatricial
tissue in uteri of cattle and sheep following
Cesarean section.

1‘ McCallum (26) in his textobook of pathology,
stated that from experimental and other studies of

the healing Of defects in smooth muscle, very

59
little activity was found in this region. Sometimes
mitotic figures were described, but more recent .
studies favored the idea that there was very little
regeneration of muscle tissue in higher vertebrates
and that healing by scar tissue brought together
the muscle edges at the site of the defect. More-
over, muscle regeneration played no conspicuous'
part in the final picture as proved by the work Of
Walsh and Loch (,7). They showed that mitotic
figures were rarely found in the uterus of the
. guinea pig more than seven days after delivery and
rarely more than eleven days when the uterus was
' injured.

Thus it appears that muscle regeneration, if
it has to play a conspicuous part in the dis-
appearance of these scars must do it early. It
was quite evident from the sections of this series
which were taken fourteen to twenty-seven days
postoperatively that this was not the case.

Study of eighteen uterine scars Showed results
similar to those reported by Covelaire and Losee
(8, 25), in that the deposition of a considerable
band of fibrin between the cut edges formed the
basis from which healing took place.

Fibroblastic proliferation which was
definitely evident in all goats, and which could

60
be considered to be normal healing, indicated that
the early process was similar to that described by
SchWarz and Paddock (A1) in the guinea pig and
rabbit.

Phaneuf and Williams (3A,-50) have reported
that the Old scars were invisible in most instances
and could not be identified at the time of re-
Operation.

The absence of a demonstrable scar over a
considerable extent of well healed uterine wall
might be due to the fact that the line of scar
tissue was originally small. Secondly, the scar
tissue, which ramified along the line of incision
between the adjacent muscle bundles, contracted
pulling the muscle bundles close together. There-
fore, as the scar contracted it simulated more and
more the normal pattern of the uterine wall and was
not demonstrable on histological examination.

In goats l, 2, 5 and 18 on histological
examination the line of incision could not be
distinguished through the sections because of
complete healing. In some of these it was difficult
in the healed uterus to locate grossly the site of
the incision line. In these, the uterus was in-

distinguishable from the unoperated uterus.

61
C. Suturing Technique

Zinke (52) in a discussion on Cesarean section
scars at the sixtyweighth annual session of the
American Medical Association, Observed, "One of the
conclusions I have reached is that it matters little
what type of sutures we use in sewing up the wound,
but that it is most important that we have an
aseptic wound; that we bring the sides of the
incision into perfect apposition. This procedure
is absolutely essential to a firm uterine scar".

In this study, three methods were used in
closing the uterine incisions. In goat 3, a single
layer of interrupted stitches Of number 50 nylon
was used to close the wound in one horn. In this
case, the sutures gave way leaving a gap of about
one centimeter and the animal died three days
after Operation. Postumortem examination revealed
the spilling of uterine contents into the abdominal
cavity and peritonitis, which could have been the
cause Of death. From this observation, it was
concluded that a single layer of number 50 nylon
does not produce a safe closure. In the remaining
animals a double row of continuous lock-stitches
or a double row of interrupted stitches were used
to close the uterine incisions. It was interesting

to note that both types of stitches gave good

62

results and healing was satisfactory in all the
cases. These results agreed with the observation
of a previous investigator (Zinke (52)).

Kerr (23) stated that the defective scar was
not due to faulty technique, but to (a) The dif-
ficulty of securing complete asepsis, owing to the
danger of infection from the vagina; (b) The
hinderance to the healing process resulting from
the degenerated state of uterine muscle post»
Operatively; (c) The irregular distribution of
the sheets of muscle forming the uterine wall;

(d) The state of unrest of the uterus subsequent

to Operation, caused not only by the retraction but
by occasional contractions during which stitches
were stretched.

The first part of Kerr?s statement does not
agree with the findings of this experiment. In
goat 5, in spite of infection, healing was com-
plete and the scar was normal. It was Observed
in this study that perfect suture technique
played a more important part in good healing,
although other factors described by Kerr may be
of additional importance.

Two essential points for producing a better
scar were observed. One was inclusion Of the

entire wall of the uterus in the suture in order

63
to secure proper coaptation Of the entire length of
the incision. The other was the prevention of
infection. There is some difference of Opinion
as to whether the uterine wounh Should be closed
with interrupted or continuous stitches.; Green and
Bloom (18) observed that closure with interrupted
stitches yielded better scars than closure with
continuous stitches. Others (1, 13, 27) have pre-
ferred continuous stitches. In this study, both
types showed good results. The continuous lock—

\

stitch was faster, therefore, it was preferred.

I

D. Suture Materials

Suture materials are an important factor in
a closure. By placing a suture one implants a
foreign body. The tissue diSposes of foreign
bodies by either digestion or burial. It digests
absorbable materials by phagocytic action and
buries the non-absorbable material in fibrous
tissue. The essential point of a good suture is
that it should be strong enough to bring and hold
the structures in apposition so that healing may
proceed unimpaired until complete. At the same
time, it should not constitute an irritating
foreign body. The tension applied to sutures

should be only sufficient to bring the tissue

6A
into apposition. There is swelling following trauma
in the process of suturing so sutures are auto-
matically tightened during healing. If tied too
tightly, they interfere with blood supply, causing
a local area of ischemia which retards healing.

The fact that a wide variety of suture
material has been used by many authors in closing
the uterine incision is sufficient proof that
none is entirely satisfactory from every point of
view. (Plain and chromic catgut, silk worm-gut,
kangaroo tendon, silk, nylon and metallic wire have
been employed at one time or another.

Holland (31) upon the analysis of a large
number of cases, found that subsequent ruptures
occurred two and a half times more frequently
after the use of catgut than after the use of silk.
On the other hand Prusman, cited by Gamble (15),
objected to non-absorbable sutures on the ground
that in the presence of infection they caused
necrosis and weakening of the scar. Bowers gt gl.
(5) and Schmitz gt g1. (A3) also favored the use
of catgut.

In this series of Operations, number 50
nylon and 00 chromic catgut were used to close
the incisions. The former showed more satis~

factory results than the latter. With catgut

65
there was marked reaction around the sutures in most
cases and in two, goats 5 and 10, omental adhesions
developed along the incision line, probably as a
result of stiff knots irritating the surrounding
tissues. With nylon very little or no reaction was
found around the suture material and the uterine
scar at the time of biopsy was free of adhesions.
This was perhaps due to the fact that the non-
absorbable material possesses great tensile
strength, consequently, fine materials could be
used thereby reducing the size of the foreign body.
Furthermore, the advantage of nonaabsorbable
materials such as nylon over catgut is that they
do not possess the power of capillary attraction
and have a smooth surface which is less irritant
to the tissue causing less tissue reaction.

According to Gamble (15), adhesions following
Cesarean section were common but in this study
adhesions were found only in two cases, so it was
not justifiable to draw any inference from these
data. It is difficult to determine just how much
harm such adhesions do. Doubtless they may give
rise to considerable abdominal discomfort, which
may occasionally be so great as to necessitate a
second operation and cause difficulties at the

time of Operation. For example, in goat 10 of

66
this series after the adhesions had been freed, the
hemorrhage from the surface of the uterus was dif-

ficult to control.

CHAPTER VI
SUMMARY AND CONCLUSIONS

Cesarean sections were performed on eight
goats producing eighteen uterine incisions. In
one goat, the two uterine incisions were sutured
with number 50 nylon using a Single row of simple
interrupted stitches and a single row of con-
tinuous lock-stitches respectively. The single
row of Simple interrupted sutures did not produce
a safe closure. The remaining uterine incisions
were sutured with either catgut or nylon using a
double row of continuous lock-stitches or two rows
of simple interrupted stitches.

Biopsies were performed at intervals fol-
lowing the Cesarean sections and macrOSCOpic and
microscopic observations made.

Microscopic examination revealed that the
edges of the wound throughout the entire line of
incision were held together by early proliferation
of fibroblasts along with blood capillaries.

A definite scar tissue develOped which could
be demonstrated 14 to 27 days postOperatively.

Muscle regeneration could not be observed in

68

the healing process.

With catgut sutures there was severe tissue
reaction in four cases with omental adhesions in
two. No such reactions were found with nylon.

Infection and adhesions played important

roles in the production of an imperfect scar.

9.

10.

ll.

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