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Effect of diverting colostomy on breaking strength of anastomoses after resection of the left side of the colon
Effect of Diverting Colostomy on Breaking Strength of Anastomoses After Resection of the Left Side of the Colon Studies in the Rat
Peter Blomquist, MD, Maim6, Sweden Hasse Jiborn, MD, Maim6, Sweden Bengt Zederfeidt, MD, Maim6, Sweden
Resection and anastomosis of the left side of the colon is associated with a high incidence of anastomotic failure [•]. Diversion of the fecal content by a proximal colostomy is often used to prevent complications. However, a considerable n u m b e r of incidences of anastomotic leakage despite proximal diversion has been reported by several investigators
[i-31.
In a previous experimental study, we reported [4] that fecal diversion by colostomy results in a marked depression of collagen metabolism in the wall of the excluded colon. Since collagen formation is of importance for intestinal wall strength and anastomotic strength development, fecal diversion might mean decreased suture holding capacity and delay of healing of an anastomos;s [5]. The aim of the present study was to investigate the effect of a proximal diverting colostomy on suture holding capacity and on breaking strength of anastomoses in the excluded left side of the colon.
Material and Methods Forty-eight Wistar male rats that weighed about 200 g were used. The animals had free access to standard laboratory pellets and water. They were randomly allocated to one of four groups treated as shown in Table I. In all groups of animals, a median laparotomy was carried out under general anesthesia (chloral hydrate 25 rag/100 g body weight intraperitoneally). In Group A, the colon was mobilized. In Groups B and C, the colon was transected at the major flexure (Figure 1). The proximal end was brought out as a terminal colostomy in the upper part of the incision. The bowel wall was fixed to the fascia and skin with 7-0 polypropylene sutures. The distal end was closed with the same suture material after emptying the fecal content in the excluded colon. In Groups C and D, 1 cm of the distal From the Deparlments of Surgery and Experimental Research, Maim0 GeneralHospital,Universityof Lurid, Maln~. Sweden. Supportedin part by grants from the Swedish Medical Research Council (Project B80-17X00640--16A) and the Medical Faculty, Universityof Lund, Sweden. Requests for reprints should be addressedto Peter Blomqulst, MO, Department of Surgery,MalmOGeneral t-lospita~,214 01 Malmb, Sweden.
712
colon 2.5 cm above the peritoneal reflection was resected. A standardized anastomosis was made using a single layer of interrupted sutures with 7-0 polypropylene. Postoperative weight development was recorded for all animals. On the seventh postoperative day, the animals were sacrificed by an overdose of ether. In Groups C and D, signs o f a n a s tomotic complications were registered. Suture holding capacity was tested in Groups A and B. A colonic resection and anastomosis was made just before sacrifice as described for Groups C and D and the anastomotic strength immediately determined. The a n a s t o m o t i c strength was again determined after 7 days of healing in Groups C and D. In each group, half of the animats were tested with the sutures in place and the other half after removal of the sutures to allow evaluation of the importance of suture support in a 7 day old anastomosis. Breaking strength of the colonic segment containing the anastomosis was made by a specially constructed tensiometer that provided constantly increasing force. The force at r u p t u r e was recorded. For collagen determination the colon and rectum were divided into five defined parts (I through V) after the mechanical strength tests. From parts III and IV, standardized 10 mm segments were taken on both sides of the anastomosis. Anastomotic segments 3p and 3d were each 5 mm in length (see Figure 1). Collagen was determined as the amount of bydroxyproline in each colonic part and segment according to the method described by Stegemann and Stalder [7] and Pikkarainen [8]. The collagen content was then calculated (micrograms hydtoxyproline per part and segment}. In the statistical analysis of the results, the means, the standard deviation, and the standard error of the means were calculated. Comparisons of the means were carried out by Student's t test for unpaired observations.
Results Postoperative weight gain was similarly delayed in Groups B, C, and D compared with the sham operated group (Group A). In Group C, no signs of anastomotic leakage were seen. In Group D, 3 of 16 animals showed signs of anastomotic leakage with small perianvstomotic abscesses. These three animals were excluded from further study. Adhesions to the anastomotic region were not seen in G r o u p C b u t were c o m m o n in G r o u p D.
The Amertcan Jouma! of Surgery
Diverting C o l o s t o m y and Anastomotic Breaking Strength
TABLE I
Treatment Protocols and Evaluation
3.0~
Group (n) A (8) B (.8) C (16) D (16)
NEWTON~SEM
Operation
Test Day 7
Sham Colostomy Colostomy, resection & anastomosis Resection & anastom0s!s
Suture holding capacity Suture holding capacity Anastomotlc strength
I 2.5
....Anastomot!c strength 2.0
COLOSTOMY
9/c
1.5
E 1[
ANASTOMOSIS_
::.:.::.:.: 1
i ":'J
1.0
k::.;
0.5
ii!!i
!~?" 2
g~ggg O
4
15/"
¥ RECTUM
T CECUM Figure 1. Sites of coIostomy and the colonic parts (! through V) and segments ( I through 5). Part l, the cecum; part It, the proxImal colon to the major flexure; part Ill, the distal colon to the anastomosis 2.5 cm above Ihe perltoneal reflecUo,T part IV, the distal colon below the anastomosis to the peritoneal reflection; part V, the rectum (nomenclature according to LindstrOm el al
Is]).
The mean value of suture holding capacity when Groups A and B were compared was approximately 35 percent higher (p <0.05) in Group B with colostomy than in Group A (see Figure 2). The anastomotic strength was approximately 45 percent lower (p <0.001) in Group C than in Group D (see Figure 2). The strength without the sutures (C2 and D2) was not statistically different from that with the sutures left in place (C1 and D1). The collagen content in the colonic parts and segments among the groups of animals is given in Figures 3 and 4 as a ratio to that in the sham operated animals (Group A). In Groups B Volume 149, June 1985
,,,
:.'I.'~
.......
fJ.//~,
A B C1 C2 fll D2 Figure 2. Suture holding capacity ( A and B) and anastomotIc sfrongfh on th~ seventh postoporattve day with sutures (.C1, D1) and w~hout s~quros (C2, £)2). A = sham operated group, B = colosfomy group; C = colosfomy and resection group; D = re. section group,
and C, the collagen content was the same in all colonic parts and segments as in Group A. In Group D, the collagen content was significantly higher in part III and in segments I through 4 than in corresponding areas in Group C. Comments
In this investigation, we studied the suture holding capacity 7 days after diverting colostomy as well as the strength of an anastomosis in the left side of the colon with and without a proximal diverting colostomy. At the present time, formation of new collagen in the anastomosis has begun [9-11]. The anastomotic strength was tested both with and without sutures to evaluate the importance of suture support 1 week postoperatively. The suture holding capacity was approximately 35 percent higher (p <0.05) in animals with a 1 week old proximal colostomy than in the sham operated animals. Suture holding capacity is determined mainly by collagen [5]. As the amount of collagen was found to be similar in the two groups, it can be assumed that collagen quality was changed. The previously reported reduced turnover rate of collagen in the excluded colon might be the basis for such a quality change [4]. The anastomotie strength on the seventh postoperative day was approximately 45 percent less (p <0.001) i~ a~imals subjected to left colon resection
713
B l o m q u i s t et al
C O L L A G E N CONTENT
1.4
! !
1.2
0"8~ •
!
!
BCD
I
~
liT
CECUM
RECTUM F/gure 3. ~ con/ant/n d/fferenf colenic parts on the seventh postoperative day in animals with cok~stomy (B), with coloslomy and tell colon anacfomosi$ ( C ), and with left colon anastomosis (D). T~e values are expressed as ratios to the value In the sham operated animals. Interrupted line indicates site of colosfomy In Grou~ B and C. Asterisks Indicate level of statistical signittcance; those within the columns Indicate differences In relation to Group C ( "p <0.05, ° ' p <0.01).
with a proximal colostomy than in those resected without a colostomy. This indicates that the presence of intraluminal content stimulates the strength development of an anastomosis. Using the data from Jiborn et al [12] for strength of the intact colonic wall (6.1 N for the left side of the colon), it can be calculated t h a t the strength of a 1 week old anastomosis in animals with and without a colostomy is only approximately 20 and 40 percent, respectively, of t h a t of the intact bowel walt. The breaking strength was similar in each resected group with and without sutures in place. ~'his suggests that suture support does not contribute to strength of colonic anastomoses 1 week after surgery, irrespective of the use of a di.verting colostomy. T h e present investigation confirms the marked increase of collagen content in the anastomotic region after colonic surgery reported in previous studies [11]. Fecal diversion, however, eliminates the postoperative collagen response. T h e findings are consistent with previous results of marked reduction in the collagen turnover rate in the excluded colonic
COLLAGEN
wall as a consequence of proximal fecal diversion [4]. We have previously reported [13] that relative bowel rest, obtained by feeding rats a low residue diet (Biosorbin ® MCT), led to unchanged postoperative strength development, despite a marked depression in colla[~en turnover in the colonic wall. Total bowel rest obtained by a colostomy seems to result in a more marked decrease in collagen turnover and a delay in anastomotic strength development. Gross anastomotic complications occurred in three animals without a diverting colost~my in comparison to no complications in animals with a colostomy. Furthermore, anastomotic adhesions were common in animals without a colostomy but were not seen at all in the animals with a diverting colostomy. T h i s suggests t h a t total bowel rest provides more uncomplicated wound healing. It should be noted that the excluded bowel was emptied of fecal contents during operation, which might reduce the risk of anastomotic leakage. The findings in the present study indicate that fecal diversion does not diminish the ability of the sutured bowel wall to withstand tearing forces. Instead, there was an increase in suture holding capacity in the excluded colon 7 days after diverting colostomy; however, total bowel rest led to a marked delay in anastomotic strength development. These differences in strength development were accompanied by a diminished collagen response in the anastomotic area after fecal diversion. Whether this represents impaired healing or is a sign of less complicated healing remains to be answered. T h e gross appearance of the anastomoses indicates t h a t colostomy prevents abscesses and adhesions.
Summary In the present investigation, the effect of a proximal diverting colostomy on suture holding capacity and on anastomotic strength of the excluded left colon was studied. Suture holding capacity was in-
CONTENT
2.4 2.2 2.0
.
'1"
•
1.8
o 1.4 2 1.o: o.8
714
:~,~
:~;
H
N
* BCD 1
2
u 3p
3d
4
5
Figure 4. Collagen content tn different colonic segments ( I through 5) on the seventh postoperative day In animals with coicstomy (B), with coloslomy and left colon anastomosl~ (C), and with left colon anasfomosls ( D). The values are expressed as ratios to the value in ihe sham operated animals. Interrupted line Indicates site of anaslomosls in Groups C and D. Asterisks Indicate level of statistical significance; those within columns Indicate differences in relation to Group C ( ' p <0.05, °°p <0.01, " ° p
The American Journal of Surgery
Diverting C o l o s t o m y and Anasto,"notlc Breaking Strength
creased 7 days after fecal diversion. Anastomotic strength development, however, was significantly delayed. These differences were accompanied by a diminished collagen response in the anastomotic region afte~ fecal diversion. This might suggest impairment of healing in the exciuded colon. The gross appearance of the anastomoses would, however, indicate that increased collagen formation and greater strength development in animals without colostomy is a result of more complicated healing.
study. Am ,} Mad Scl 1887;94:436-61. 6. Undstrbm CG, Rosengren J-E, Fork FT. Colon of the rat. An anatomic, hlatologic and radiographic Investigation. Acts Radlol (Oiagn) 1979;20:523-36. 7. Stegernann H, Staldef K. I.')etermlnatlon of hydroxyproline. Clin Chlm Acte 1967;18:267-73. 8, Plkkaralnen J. The molecular structures of vertebrate skin collagens. Acta Physlol 1968;309 (suppl):23-5. 9. Cronln K, Jackson DS, Dunphy JE. Changing bursting strength and collagen content of the healing colon. Surg Gynecol Obstet 1968;126:747-53. 10. IP,dn TT, Hunt TK. Reappraisal of the healing process of anastomosis of the colon. Surg Gynecol Obstot 1974;138:
References
11. BIomqu~at P, AhonenJ, Jiborn H, Zederleidt B. The effect of relative bowel rest on heeling of colonic anastomoses. Collagen synthesis and content in the colonic well after left colon resection and anastomosis In the rat. Acta Chtr Scand 1984; 150:677-61. 12. Jiborn H, Ahonen J, ZederfelcIt B. Healing of experimental coIonic anastomoses. II. Breaking strength of the colon after left colon resection and anastomosis. Am J Surg 1978; 136:595-9. 13. Blomqulst P, JIborn H, Zederfaldt B. The effect of relative bowel rest on healing of colonic anastomoses. Breaking strength and collagen in the colonic wall following left colon resection arid anastomosis in the rat. Acta Chit So.and 1984;150: 671-5.
74,~6.
1. Gollgher JC, Graham NG, de Dombal FT. Anastomotlc dehiscence after anterior resection of rectum and slgmoid. Br J Surg 1970;57:109-18. 2. Sct~ock TR, Dever~y CW, Ou~phy JE. Factors contrtbut|ng to leakage of colonic anastomoses. Ann Surg 1973;177: 513-8. 3. Were P, S@rensen K, Berg V. Proximal fecal diversion. Dis Colon Rectum 1981;24:114-9. 4. Blomqulst P, Jibom H, Zederfeldt B. Effect of diverting colostom), on collagen metabolism in the colonic wall. Studies In the rat. Am J Surg 1985;149:330-3. 5. Heisted W~. Circular suture of the intestine: an experimental
Volume 149, June t985
715
Peter Blomquist, MD, Maim6, Sweden Hasse Jiborn, MD, Maim6, Sweden Bengt Zederfeidt, MD, Maim6, Sweden
Resection and anastomosis of the left side of the colon is associated with a high incidence of anastomotic failure [•]. Diversion of the fecal content by a proximal colostomy is often used to prevent complications. However, a considerable n u m b e r of incidences of anastomotic leakage despite proximal diversion has been reported by several investigators
[i-31.
In a previous experimental study, we reported [4] that fecal diversion by colostomy results in a marked depression of collagen metabolism in the wall of the excluded colon. Since collagen formation is of importance for intestinal wall strength and anastomotic strength development, fecal diversion might mean decreased suture holding capacity and delay of healing of an anastomos;s [5]. The aim of the present study was to investigate the effect of a proximal diverting colostomy on suture holding capacity and on breaking strength of anastomoses in the excluded left side of the colon.
Material and Methods Forty-eight Wistar male rats that weighed about 200 g were used. The animals had free access to standard laboratory pellets and water. They were randomly allocated to one of four groups treated as shown in Table I. In all groups of animals, a median laparotomy was carried out under general anesthesia (chloral hydrate 25 rag/100 g body weight intraperitoneally). In Group A, the colon was mobilized. In Groups B and C, the colon was transected at the major flexure (Figure 1). The proximal end was brought out as a terminal colostomy in the upper part of the incision. The bowel wall was fixed to the fascia and skin with 7-0 polypropylene sutures. The distal end was closed with the same suture material after emptying the fecal content in the excluded colon. In Groups C and D, 1 cm of the distal From the Deparlments of Surgery and Experimental Research, Maim0 GeneralHospital,Universityof Lurid, Maln~. Sweden. Supportedin part by grants from the Swedish Medical Research Council (Project B80-17X00640--16A) and the Medical Faculty, Universityof Lund, Sweden. Requests for reprints should be addressedto Peter Blomqulst, MO, Department of Surgery,MalmOGeneral t-lospita~,214 01 Malmb, Sweden.
712
colon 2.5 cm above the peritoneal reflection was resected. A standardized anastomosis was made using a single layer of interrupted sutures with 7-0 polypropylene. Postoperative weight development was recorded for all animals. On the seventh postoperative day, the animals were sacrificed by an overdose of ether. In Groups C and D, signs o f a n a s tomotic complications were registered. Suture holding capacity was tested in Groups A and B. A colonic resection and anastomosis was made just before sacrifice as described for Groups C and D and the anastomotic strength immediately determined. The a n a s t o m o t i c strength was again determined after 7 days of healing in Groups C and D. In each group, half of the animats were tested with the sutures in place and the other half after removal of the sutures to allow evaluation of the importance of suture support in a 7 day old anastomosis. Breaking strength of the colonic segment containing the anastomosis was made by a specially constructed tensiometer that provided constantly increasing force. The force at r u p t u r e was recorded. For collagen determination the colon and rectum were divided into five defined parts (I through V) after the mechanical strength tests. From parts III and IV, standardized 10 mm segments were taken on both sides of the anastomosis. Anastomotic segments 3p and 3d were each 5 mm in length (see Figure 1). Collagen was determined as the amount of bydroxyproline in each colonic part and segment according to the method described by Stegemann and Stalder [7] and Pikkarainen [8]. The collagen content was then calculated (micrograms hydtoxyproline per part and segment}. In the statistical analysis of the results, the means, the standard deviation, and the standard error of the means were calculated. Comparisons of the means were carried out by Student's t test for unpaired observations.
Results Postoperative weight gain was similarly delayed in Groups B, C, and D compared with the sham operated group (Group A). In Group C, no signs of anastomotic leakage were seen. In Group D, 3 of 16 animals showed signs of anastomotic leakage with small perianvstomotic abscesses. These three animals were excluded from further study. Adhesions to the anastomotic region were not seen in G r o u p C b u t were c o m m o n in G r o u p D.
The Amertcan Jouma! of Surgery
Diverting C o l o s t o m y and Anastomotic Breaking Strength
TABLE I
Treatment Protocols and Evaluation
3.0~
Group (n) A (8) B (.8) C (16) D (16)
NEWTON~SEM
Operation
Test Day 7
Sham Colostomy Colostomy, resection & anastomosis Resection & anastom0s!s
Suture holding capacity Suture holding capacity Anastomotlc strength
I 2.5
....Anastomot!c strength 2.0
COLOSTOMY
9/c
1.5
E 1[
ANASTOMOSIS_
::.:.::.:.: 1
i ":'J
1.0
k::.;
0.5
ii!!i
!~?" 2
g~ggg O
4
15/"
¥ RECTUM
T CECUM Figure 1. Sites of coIostomy and the colonic parts (! through V) and segments ( I through 5). Part l, the cecum; part It, the proxImal colon to the major flexure; part Ill, the distal colon to the anastomosis 2.5 cm above Ihe perltoneal reflecUo,T part IV, the distal colon below the anastomosis to the peritoneal reflection; part V, the rectum (nomenclature according to LindstrOm el al
Is]).
The mean value of suture holding capacity when Groups A and B were compared was approximately 35 percent higher (p <0.05) in Group B with colostomy than in Group A (see Figure 2). The anastomotic strength was approximately 45 percent lower (p <0.001) in Group C than in Group D (see Figure 2). The strength without the sutures (C2 and D2) was not statistically different from that with the sutures left in place (C1 and D1). The collagen content in the colonic parts and segments among the groups of animals is given in Figures 3 and 4 as a ratio to that in the sham operated animals (Group A). In Groups B Volume 149, June 1985
,,,
:.'I.'~
.......
fJ.//~,
A B C1 C2 fll D2 Figure 2. Suture holding capacity ( A and B) and anastomotIc sfrongfh on th~ seventh postoporattve day with sutures (.C1, D1) and w~hout s~quros (C2, £)2). A = sham operated group, B = colosfomy group; C = colosfomy and resection group; D = re. section group,
and C, the collagen content was the same in all colonic parts and segments as in Group A. In Group D, the collagen content was significantly higher in part III and in segments I through 4 than in corresponding areas in Group C. Comments
In this investigation, we studied the suture holding capacity 7 days after diverting colostomy as well as the strength of an anastomosis in the left side of the colon with and without a proximal diverting colostomy. At the present time, formation of new collagen in the anastomosis has begun [9-11]. The anastomotic strength was tested both with and without sutures to evaluate the importance of suture support 1 week postoperatively. The suture holding capacity was approximately 35 percent higher (p <0.05) in animals with a 1 week old proximal colostomy than in the sham operated animals. Suture holding capacity is determined mainly by collagen [5]. As the amount of collagen was found to be similar in the two groups, it can be assumed that collagen quality was changed. The previously reported reduced turnover rate of collagen in the excluded colon might be the basis for such a quality change [4]. The anastomotie strength on the seventh postoperative day was approximately 45 percent less (p <0.001) i~ a~imals subjected to left colon resection
713
B l o m q u i s t et al
C O L L A G E N CONTENT
1.4
! !
1.2
0"8~ •
!
!
BCD
I
~
liT
CECUM
RECTUM F/gure 3. ~ con/ant/n d/fferenf colenic parts on the seventh postoperative day in animals with cok~stomy (B), with coloslomy and tell colon anacfomosi$ ( C ), and with left colon anastomosis (D). T~e values are expressed as ratios to the value In the sham operated animals. Interrupted line indicates site of colosfomy In Grou~ B and C. Asterisks Indicate level of statistical signittcance; those within the columns Indicate differences In relation to Group C ( "p <0.05, ° ' p <0.01).
with a proximal colostomy than in those resected without a colostomy. This indicates that the presence of intraluminal content stimulates the strength development of an anastomosis. Using the data from Jiborn et al [12] for strength of the intact colonic wall (6.1 N for the left side of the colon), it can be calculated t h a t the strength of a 1 week old anastomosis in animals with and without a colostomy is only approximately 20 and 40 percent, respectively, of t h a t of the intact bowel walt. The breaking strength was similar in each resected group with and without sutures in place. ~'his suggests that suture support does not contribute to strength of colonic anastomoses 1 week after surgery, irrespective of the use of a di.verting colostomy. T h e present investigation confirms the marked increase of collagen content in the anastomotic region after colonic surgery reported in previous studies [11]. Fecal diversion, however, eliminates the postoperative collagen response. T h e findings are consistent with previous results of marked reduction in the collagen turnover rate in the excluded colonic
COLLAGEN
wall as a consequence of proximal fecal diversion [4]. We have previously reported [13] that relative bowel rest, obtained by feeding rats a low residue diet (Biosorbin ® MCT), led to unchanged postoperative strength development, despite a marked depression in colla[~en turnover in the colonic wall. Total bowel rest obtained by a colostomy seems to result in a more marked decrease in collagen turnover and a delay in anastomotic strength development. Gross anastomotic complications occurred in three animals without a diverting colost~my in comparison to no complications in animals with a colostomy. Furthermore, anastomotic adhesions were common in animals without a colostomy but were not seen at all in the animals with a diverting colostomy. T h i s suggests t h a t total bowel rest provides more uncomplicated wound healing. It should be noted that the excluded bowel was emptied of fecal contents during operation, which might reduce the risk of anastomotic leakage. The findings in the present study indicate that fecal diversion does not diminish the ability of the sutured bowel wall to withstand tearing forces. Instead, there was an increase in suture holding capacity in the excluded colon 7 days after diverting colostomy; however, total bowel rest led to a marked delay in anastomotic strength development. These differences in strength development were accompanied by a diminished collagen response in the anastomotic area after fecal diversion. Whether this represents impaired healing or is a sign of less complicated healing remains to be answered. T h e gross appearance of the anastomoses indicates t h a t colostomy prevents abscesses and adhesions.
Summary In the present investigation, the effect of a proximal diverting colostomy on suture holding capacity and on anastomotic strength of the excluded left colon was studied. Suture holding capacity was in-
CONTENT
2.4 2.2 2.0
.
'1"
•
1.8
o 1.4 2 1.o: o.8
714
:~,~
:~;
H
N
* BCD 1
2
u 3p
3d
4
5
Figure 4. Collagen content tn different colonic segments ( I through 5) on the seventh postoperative day In animals with coicstomy (B), with coloslomy and left colon anastomosl~ (C), and with left colon anasfomosls ( D). The values are expressed as ratios to the value in ihe sham operated animals. Interrupted line Indicates site of anaslomosls in Groups C and D. Asterisks Indicate level of statistical significance; those within columns Indicate differences in relation to Group C ( ' p <0.05, °°p <0.01, " ° p
The American Journal of Surgery
Diverting C o l o s t o m y and Anasto,"notlc Breaking Strength
creased 7 days after fecal diversion. Anastomotic strength development, however, was significantly delayed. These differences were accompanied by a diminished collagen response in the anastomotic region afte~ fecal diversion. This might suggest impairment of healing in the exciuded colon. The gross appearance of the anastomoses would, however, indicate that increased collagen formation and greater strength development in animals without colostomy is a result of more complicated healing.
study. Am ,} Mad Scl 1887;94:436-61. 6. Undstrbm CG, Rosengren J-E, Fork FT. Colon of the rat. An anatomic, hlatologic and radiographic Investigation. Acts Radlol (Oiagn) 1979;20:523-36. 7. Stegernann H, Staldef K. I.')etermlnatlon of hydroxyproline. Clin Chlm Acte 1967;18:267-73. 8, Plkkaralnen J. The molecular structures of vertebrate skin collagens. Acta Physlol 1968;309 (suppl):23-5. 9. Cronln K, Jackson DS, Dunphy JE. Changing bursting strength and collagen content of the healing colon. Surg Gynecol Obstet 1968;126:747-53. 10. IP,dn TT, Hunt TK. Reappraisal of the healing process of anastomosis of the colon. Surg Gynecol Obstot 1974;138:
References
11. BIomqu~at P, AhonenJ, Jiborn H, Zederleidt B. The effect of relative bowel rest on heeling of colonic anastomoses. Collagen synthesis and content in the colonic well after left colon resection and anastomosis In the rat. Acta Chtr Scand 1984; 150:677-61. 12. Jiborn H, Ahonen J, ZederfelcIt B. Healing of experimental coIonic anastomoses. II. Breaking strength of the colon after left colon resection and anastomosis. Am J Surg 1978; 136:595-9. 13. Blomqulst P, JIborn H, Zederfaldt B. The effect of relative bowel rest on healing of colonic anastomoses. Breaking strength and collagen in the colonic wall following left colon resection arid anastomosis in the rat. Acta Chit So.and 1984;150: 671-5.
74,~6.
1. Gollgher JC, Graham NG, de Dombal FT. Anastomotlc dehiscence after anterior resection of rectum and slgmoid. Br J Surg 1970;57:109-18. 2. Sct~ock TR, Dever~y CW, Ou~phy JE. Factors contrtbut|ng to leakage of colonic anastomoses. Ann Surg 1973;177: 513-8. 3. Were P, S@rensen K, Berg V. Proximal fecal diversion. Dis Colon Rectum 1981;24:114-9. 4. Blomqulst P, Jibom H, Zederfeldt B. Effect of diverting colostom), on collagen metabolism in the colonic wall. Studies In the rat. Am J Surg 1985;149:330-3. 5. Heisted W~. Circular suture of the intestine: an experimental
Volume 149, June t985
715