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The Effect of Section of Both Sacral Nerves on Intravesical Pressure
THE EFFECT OF SECTION OF BOTH SACRAL NERVES ON INTRAVESICAL PRESSURE AN EXPERIMENTAL STUDY1 J. CRAIG POTTER
The Mayo Foundation, Rochester, Minnesota Received for publication August 23, 1925
Atony of the bladder, as a result of injury to the peripheral nerves is rather a rare clinical finding. In the hope of throwing some light on this condition a series of experiments was planned, to study the effect of section of the various nerves supplying the bladder, and to observe the result of such injury on the intact dog. LITERATURE
Considerable work has been done by various observers to determine the nervous control of the bladder. In general their findings are that the hypogastric nerves affect mainly the neck and trigone, while the nervi erigentes control the bladder muscle proper. Elliott reconciled the various conclusions of others by finding that the control varied from species to species. In a general way he found that the sacral nerves contract the bladder and relax the sphincter, while the hypogastric nerves relax the bladder and contract the sphincter. This is most marked in the cat. In the dog the inhibitory mechanism is less highly developed. Harrington reports that division of the posterior sacral roots in the cat permanently abolishes micturition. He found that section of the sacral nerves causes retention, followed in a few days by interval urination which takes place in a series of feeble spurts with a tendency toward residual urine. 1 Work done in the Section on Urology and Division of Experimental Surgery and Pathology, Institute of Experimental Medicine.
197
198
J. CRAIG POTTER
The results of other investigators do not agree, nor do they give adequate explanation of the variation. The mechanism of the bladder has not been explained by any of the experimental work that has been carried out. TECHNIC AND METHOD
Quiet, docile dogs were selected for the experimental work. The bladder was emptied by catheterization. No. 12 and No. 14 catheters and a small curved metal catheter were used. Little difference could be seen so far as the results were concerned. Great care was necessary in manipulating the catheters to prevent hematuria. The metal catheter was the most easily handled. The tone of the bladder was determined by filling it with 10 cc. of a 12.5 per cent solution of sodium iodid for each kilogram of body weight, and then taking the pressure in centimeters by allowing the solution to flow out through the catheter into a 2 mm. glass tube attached to a meter rod. The level of the external urethral orifice was selected as the point for the zero reading. Following this a cystogram was taken to record the form of the bladder and the reflux up the ureters. Two animals were used as controls. The others, after a varying number of readings (two or three) were etherized, and under sterile technic, a low abdominal incision was made in the median line, the sacral nerves were severed on each side, doubly ligated, and the ends separated as far as possible. At intervals of from two to six weeks following this the intravesical pressure per constant volume was taken and roentgenograms made. In making the observations it is important to have the dog's head supported so as to cause the abdominal muscles to relax; otherwise wide variations in readings will occur from very slight movements. The observations extended over about nine months. RESULTS
In general the readings of intravesical pressure, immediately and remotely after section of the sacral nerves in the dog, were the same as the preoperative readings (fig. 1).
199
EFFECT OF SECTION OF SACRAL NERVES
The cystograms never showed any reflux up the ureters. The dogs had perfect vesical control; there was no dribbling, and they voided at intervals. No residual urine was obtained by catheter after micturition. Infectious sarcoma of the vulva appeared in one of the control dogs, and this probably accounts for the curve shown. It was then necessary to discard the animal. The sharp rises in pressure recorded are due, in the main, to the play of the abdominal muscles when the dogs were restless. MM
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5
THE lNTRAVESICAL TONE BEFORE AND AFTER SECTION OF BOTH SACRAL NERVES
The slight drop in tone seen in the first part of the chart is probably due to the animal's becoming more accustomed to the procedures. As the pressure readings of three of the dogs before operation were taken in a slightly different manner from the other readings, they have not been recorded in the graph. They were essentially the same as those found after operation. COMMENT
An alternative method of recording changes in the vesical pressure was considered. It consisted of keeping the pressure
200
J. CRAIG POTTER
constant and varying the volume of the contents. It was not found to be feasible because the least elevation of the dog's head or turn of the body affects the result. It was very necessary to keep the animal quiet and at ease to avoid contradictory results. It is probable that if the bladder were filled with 5 cc. of the solution for each kilogram of body weight, less trouble would need to be taken in preventing the animal from making slight movements. CONCLUSION
Section of both sacral nerves in the dog does not affect the vesical tone, nor the mechanism of micturition; neither does it cause retention of urine nor reflux up the ureter. REFERENCES (1) BARRINGTON, F. J. F.: The nervous mechanism of micturition. Quart. Jour. Exper. Physiol., 1915, viii, 33-71. (2) ELLIOTT, T. R.: The innervation of the bladder and urethra. Jour. Physiol., 1906-1907, XXXV, 367--445.
The Mayo Foundation, Rochester, Minnesota Received for publication August 23, 1925
Atony of the bladder, as a result of injury to the peripheral nerves is rather a rare clinical finding. In the hope of throwing some light on this condition a series of experiments was planned, to study the effect of section of the various nerves supplying the bladder, and to observe the result of such injury on the intact dog. LITERATURE
Considerable work has been done by various observers to determine the nervous control of the bladder. In general their findings are that the hypogastric nerves affect mainly the neck and trigone, while the nervi erigentes control the bladder muscle proper. Elliott reconciled the various conclusions of others by finding that the control varied from species to species. In a general way he found that the sacral nerves contract the bladder and relax the sphincter, while the hypogastric nerves relax the bladder and contract the sphincter. This is most marked in the cat. In the dog the inhibitory mechanism is less highly developed. Harrington reports that division of the posterior sacral roots in the cat permanently abolishes micturition. He found that section of the sacral nerves causes retention, followed in a few days by interval urination which takes place in a series of feeble spurts with a tendency toward residual urine. 1 Work done in the Section on Urology and Division of Experimental Surgery and Pathology, Institute of Experimental Medicine.
197
198
J. CRAIG POTTER
The results of other investigators do not agree, nor do they give adequate explanation of the variation. The mechanism of the bladder has not been explained by any of the experimental work that has been carried out. TECHNIC AND METHOD
Quiet, docile dogs were selected for the experimental work. The bladder was emptied by catheterization. No. 12 and No. 14 catheters and a small curved metal catheter were used. Little difference could be seen so far as the results were concerned. Great care was necessary in manipulating the catheters to prevent hematuria. The metal catheter was the most easily handled. The tone of the bladder was determined by filling it with 10 cc. of a 12.5 per cent solution of sodium iodid for each kilogram of body weight, and then taking the pressure in centimeters by allowing the solution to flow out through the catheter into a 2 mm. glass tube attached to a meter rod. The level of the external urethral orifice was selected as the point for the zero reading. Following this a cystogram was taken to record the form of the bladder and the reflux up the ureters. Two animals were used as controls. The others, after a varying number of readings (two or three) were etherized, and under sterile technic, a low abdominal incision was made in the median line, the sacral nerves were severed on each side, doubly ligated, and the ends separated as far as possible. At intervals of from two to six weeks following this the intravesical pressure per constant volume was taken and roentgenograms made. In making the observations it is important to have the dog's head supported so as to cause the abdominal muscles to relax; otherwise wide variations in readings will occur from very slight movements. The observations extended over about nine months. RESULTS
In general the readings of intravesical pressure, immediately and remotely after section of the sacral nerves in the dog, were the same as the preoperative readings (fig. 1).
199
EFFECT OF SECTION OF SACRAL NERVES
The cystograms never showed any reflux up the ureters. The dogs had perfect vesical control; there was no dribbling, and they voided at intervals. No residual urine was obtained by catheter after micturition. Infectious sarcoma of the vulva appeared in one of the control dogs, and this probably accounts for the curve shown. It was then necessary to discard the animal. The sharp rises in pressure recorded are due, in the main, to the play of the abdominal muscles when the dogs were restless. MM
_r ,_..__.
800 70 0
600
,I
-@" 400 ~ 300~
9-.
100
~~\ Q1_ -- _',! '{_~_
0
~
200
r-,.._,_
Q
6
7
6
/
/
I'---,
--
'
FIG. 1.
I
'-
1,v
"'-
" 1 /.
V
/
/4
1924
9
10
sa:.ra~ ne Ive~
I"-
t
W' V
,,-/
/
/
r---,
~ '¾..
"-
I/ ~./
r-0 I"-
/
-
/
V
I~
1--- ~
./
.:::-i--.." :/'./ .,'I-,-1 55
C
l.t.:-- ~
I
GBO) ~ r. ALlA "- ~
Month
"-
I
~
,n
I'-..
b
1
500
oS ~cti
" I'-..
I\
on
11
12
2
.3
192.S
4
5
THE lNTRAVESICAL TONE BEFORE AND AFTER SECTION OF BOTH SACRAL NERVES
The slight drop in tone seen in the first part of the chart is probably due to the animal's becoming more accustomed to the procedures. As the pressure readings of three of the dogs before operation were taken in a slightly different manner from the other readings, they have not been recorded in the graph. They were essentially the same as those found after operation. COMMENT
An alternative method of recording changes in the vesical pressure was considered. It consisted of keeping the pressure
200
J. CRAIG POTTER
constant and varying the volume of the contents. It was not found to be feasible because the least elevation of the dog's head or turn of the body affects the result. It was very necessary to keep the animal quiet and at ease to avoid contradictory results. It is probable that if the bladder were filled with 5 cc. of the solution for each kilogram of body weight, less trouble would need to be taken in preventing the animal from making slight movements. CONCLUSION
Section of both sacral nerves in the dog does not affect the vesical tone, nor the mechanism of micturition; neither does it cause retention of urine nor reflux up the ureter. REFERENCES (1) BARRINGTON, F. J. F.: The nervous mechanism of micturition. Quart. Jour. Exper. Physiol., 1915, viii, 33-71. (2) ELLIOTT, T. R.: The innervation of the bladder and urethra. Jour. Physiol., 1906-1907, XXXV, 367--445.