Intestinal Anastomosis 
Richard Davis 
OPEN MANUAL OF SURGERY IN RESOURCE-LIMITED SETTINGS 
www.vumc.org/global-surgical-atlas 
This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License  
 
Introduction:  
In this chapter we present one technique for a 
hand-sewn bowel anastomosis. There are many ways 
to anastomose bowel using sutures, staples, or a 
combination of the two. All successful anastomoses 
will involve well vascularized tissue, under no 
tension, with the bowel being inverted, or folded into 
itself. Our technique is easy to learn, easy to teach, 
and relatively safe even in inexperienced hands. 
Please note as you review the pictures that this 
technique assumes both surgeons sew the inner layer 
by passing the needle from their left to their right. 
 
This is the same two layered technique we 
use for Billroth 1 gastroduodenostomy after partial 
gastrectomy, see that chapter for more photos and 
explanation of the technique.  
 
Two layer, hand sewn intestinal anastomosis 
proceeds according to the following steps: 
● Alignment of the two pieces of bowel with 
traction sutures 
● Posterior outer layer- interrupted 
● Posterior inner layer- running 
● Anterior inner layer- running 
● Anterior outer layer- interrupted 
● Closure of any mesenteric defect. 
 
Steps: 
1. The two ends of the bowel should not be kinked 
or twisted- this can be confirmed by aligning the 
mesenteries of both segments. The two ends 
should meet with absolutely no tension. 
Especially when anastomosing the colon, we 
prefer to see and feel a pulsatile vessel in the 
mesentery immediately adjacent to the cut edge 
of the bowel. Place a traction suture through the 
serosa and muscular layer of the mesenteric and 
antimesenteric sides of the bowel to align it. If 
possible, it should be aligned so that the 
anastomosis will be in a line between the two 
operators, as shown below: 
 
Traction sutures through the serosa and muscular layer of the 
bowel on both sides of the anastomosis, on both the 
antimesenteric (top) and mesenteric (bottom) layers of the 
bowel. The locations of the two surgeons are also shown here; 
preferably the anastomosis will be parallel to a line drawn 
between them.  
 
2. Tie the traction sutures and put them on slight 
tension, aligning the bowel.  
 
Well placed traction sutures will align the bowel so that the two 
lumens lie next to each other and are ready to be sewn together.  
Intestinal Anastomosis 
Richard Davis 
OPEN MANUAL OF SURGERY IN RESOURCE-LIMITED SETTINGS 
www.vumc.org/global-surgical-atlas 
This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License  
 
 
As seen here, the traction sutures hold and align the pieces of 
bowel that are to be anastomosed. The surgeon is preparing to 
place the posterior outer layer of sutures, as described further 
below. These photographs are from the closure of a loop 
colostomy: both ends of the bowel easily reached the skin, 
where the anastomosis was performed. Once the anastomosis 
was complete, it was placed  inside the abdomen and the fascia 
was closed.  
  
3. Perform the posterior outer layer of the 
anastomosis, passing the needle through the 
serosa and muscular layers of the bowel on both 
sides, aligning it further. We prefer interrupted 
sutures for this layer. 
 
Place interrupted seromuscular sutures about 3-5mm apart in 
between the two traction sutures. This is the posterior outer 
layer of the anastomosis. Either surgeon may perform this step. 
 
The posterior outer layer is complete and the two lumens of the 
bowel are aligned and ready for the posterior inner layer.  
 
4. Surgeon A begins the posterior inner layer of the 
anastomosis by suturing the mucosa of both sides 
together, right in the center. Put a hemostat on the 
other side of the suture, Surgeon B will tie to it 
later. Surgeon A then sews towards her/himself. 
 
Intestinal Anastomosis 
Richard Davis 
OPEN MANUAL OF SURGERY IN RESOURCE-LIMITED SETTINGS 
www.vumc.org/global-surgical-atlas 
This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License  
 
 
Surgeon A, standing inferior to this picture, has tied the suture 
and is about to start a running suture, sewing towards 
her/himself. 
 
5. Surgeon A continues the posterior inner layer 
suturing towards her/himself. Once you reach the 
edge of the bowel, you will pass the suture 
through each side separately.  
 
As the running suture nears the edge of the bowel, Surgeon A 
must be mindful of the orientation of each stitch. This one is 
passed from inside to outside the lumen of the bowel on Surgeon 
A’s  right. 
 
This photo shows that the most recent stitch has been taken on 
the lumen to the right, from inside out. The needle is now 
outside the lumen of the bowel, and the next stitch will be from 
the outside in on the lumen to the left.  
 
6. When surgeon A reaches the edge of the bowel, 
it is critically important to remember when the 
needle is inside and when it is outside the bowel. 
Each pass of the needle will now be separate, 
going from inside to outside the lumen, and then 
from outside to inside. Failure to maintain this 
orientation can result in an anastomotic leak.  
 
Surgeon A now passes the needle from outside the lumen to 
inside on the bowel on the left.  
 
Intestinal Anastomosis 
Richard Davis 
OPEN MANUAL OF SURGERY IN RESOURCE-LIMITED SETTINGS 
www.vumc.org/global-surgical-atlas 
This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License  
 
 
The needle passes from outside to inside on the bowel on the 
left. 
 
7. After a few such “corner” stitches, Surgeon A is 
finished. The suture is left outside the lumen by 
convention, so that later, when Surgeon B starts 
suturing with it, it is clear what should be done 
next. Do not tie the suture at this point.  
 
Surgeon A is finished, having taken 3-4 such stitches and having 
“rounded the corner.” Do not tie the suture at this point: later  
on, Surgeon B will continue sewing with this suture towards 
him/herself, performing the anterior inner layer.  
 
8. Surgeon B then passes another suture adjacent to 
Surgeon A’s original knot, ties the suture, and 
then ties to the tail of Surgeon A’s knot.  
 
Surgeon B now starts their part of the posterior inner layer, 
passing the first stitch through the mucosa next to the knot that 
Surgeon A had tied previously.  
 
 
Surgeon B ties the suture to itself. The tail of surgeon A’s suture 
is held by a hemostat.   
Intestinal Anastomosis 
Richard Davis 
OPEN MANUAL OF SURGERY IN RESOURCE-LIMITED SETTINGS 
www.vumc.org/global-surgical-atlas 
This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License  
 
 
Surgeon B then ties the suture to the tail of Surgeon A’s knot, 
still held by the hemostat in this picture. 
 
9. Surgeon B then begins sewing towards 
him/herself, just as Surgeon A did. Upon 
reaching the edge of the bowel, Surgeon B must 
also remember to pass the needle inwards to and 
outwards from the lumen, taking the last stitch 
from inside out.  
 
Surgeon B now sews their portion of the posterior inner layer, 
obeying the same rules as described above. For Surgeon B, 
standing opposite the viewer in this picture, the needle passes 
inside-out on the side that is on their right, as shown above. 
Surgeon A will now take this needle and begin the anterior 
inner layer of the anastomosis.  
 
Surgeon B continues “rounding the corner” and eventually 
takes their final bite of the posterior inner layer, passing the 
needle through the lumen on their right and leaving the suture 
outside the lumen.  
 
10. Surgeon A now takes the needle opposite them 
(that was previously placed by Surgeon B) and 
begins sewing the anterior inner layer of the 
anastomosis, towards her/himself. Be careful 
during this stage that you see the needle as it 
passes, so you do not catch the “back wall” of the 
anastomosis and narrow it. 
 
Surgeon A is now sewing the anterior inner layer, using the 
needle that Surgeon B just finished with. The needle continues 
in the same orientation of “outside-in, inside-out” that Surgeon 
B was doing. If this transfer was done correctly, the direction 
and inside-out orientation of the needle is unchanged. 
Intestinal Anastomosis 
Richard Davis 
OPEN MANUAL OF SURGERY IN RESOURCE-LIMITED SETTINGS 
www.vumc.org/global-surgical-atlas 
This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License  
 
 
Surgeon A is now sewing the anterior inner layer, using the 
suture that Surgeon B has just finished with.  
 
11. Once Surgeon A has reached approximately the 
center of the bowel, Surgeon B takes the opposite 
needle (previously placed by Surgeon A in step 
7) and starts sewing towards themselves. As the 
remaining defect becomes smaller, it becomes 
easier to inadvertently catch the “back wall” with 
your needle.  
 
Surgeon B has taken the needle left by Surgeon A (in Step 7) 
and started sewing, towards him/herself, the anterior inner 
layer of the anastomosis.  
 
Surgeon B is sewing towards him/herself and finishing the 
anterior inner layer of the anastomosis.  
 
12. Once the two needles meet in the middle, they 
should be on opposite sides of the bowel. They 
are then tied to each other (by either operator,) 
finishing the anterior inner layer of the 
anastomosis.  
 
The completed anterior inner layer, with both sutures meeting 
in the middle and tied to each other.  
Intestinal Anastomosis 
Richard Davis 
OPEN MANUAL OF SURGERY IN RESOURCE-LIMITED SETTINGS 
www.vumc.org/global-surgical-atlas 
This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License  
 
 
Appearance of the bowel after the anterior inner layer is 
complete. The next step is to completely bury this suture line, 
just as the posterior inner layer was “buried” by the posterior 
outer layer in Step 3 
 
13. At this time the anterior outer, interrupted layer 
is sewn by either of the surgeons. The needle 
takes a bite of the serosa and muscularis from 
either side of the previously completed 
anastomosis. These stitches are taken a few mm 
from the suture line on either side. When tied, 
this suture has the effect of “burying” the 
previous suture line. This is called a Lembert 
stitch. 
 
 
A bite of serosa and muscularis is taken from either side of the 
suture line. Each bite is taken with a separate pass of the needle, 
making it more likely that the suture line will be “buried.”  
 
 
 
 
Once the Lembert stitch is tied, the previous suture line 
becomes inverted, as shown.  
 
 
It may be tempting to take both bites with a single pass of the 
needle at this point, but the inversion of the suture line will be 
more complete if each bite is taken separately.  
 
14. These interrupted sutures are placed 3-5mm 
apart, on the anterior aspect of the anastomosis 
all the way between the two traction sutures.  
Intestinal Anastomosis 
Richard Davis 
OPEN MANUAL OF SURGERY IN RESOURCE-LIMITED SETTINGS 
www.vumc.org/global-surgical-atlas 
This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License  
 
 
Once all the Lembert sutures have been placed, there will be a 
continuous line of these sutures between the two traction 
sutures. The suture line of the inner layer is completely covered 
and inverted by the outer layer.  
 
 
The anastomosis is now complete, with two separate layers of 
sutures making an anastomosis that is inverted on itself 
circumferentially.  
 
15. A defect in the mesentery will often remain. 
Close this with interrupted sutures, taking care 
not to encircle and ligate any blood vessels that 
are supplying the anastomosis.  
16. Postoperative care includes allowing the patient 
to take clear liquids and awaiting flatus. Continue 
IV fluids during this time, as the patient will not 
be able to keep hydrated until gastrointestinal 
function resumes. Some surgeons will advance 
the diet beyond clear liquids before the patient 
passes flatus. Doing so has no effect on the 
anastomotic leak rate at all, but patients will not 
tolerate much intake by mouth until all of their 
GI tract has awakened.  
17. Generally, patients will restrict their own feeds 
until they are ready to eat. No feeding strategy 
has proven to be superior as long as pain is well 
controlled and hyperglycemia, hypoxia, and 
hypotension are avoided. However, patients who 
are confused or otherwise not mentally 
competent should not be given unlimited food or 
drink, as they may overeat and vomit.  
 
Pitfalls 
● Any technical error, especially not remembering 
the orientation of the needle relative to the lumen, 
may result in a leak. You may even choose to say 
out loud the words, “Outside in” and “Inside out” 
as you pass the needle, to help yourself remember 
which one you did last.  
● Some surgeons like to manipulate the bowel, 
“pinching” the lumen to be sure that it is patent. 
We prefer not to manipulate the anastomosis 
excessively once it is complete. If you carefully 
follow these principles you will not need to 
“verify” anything once you are done.  
● Recognizing an anastomotic leak can be very 
difficult. The signs can be very subtle. We 
discuss this matter further in Recognizing 
Postoperative Intra-Abdominal Sepsis. 
 
Richard  Davis, MD FACS FCS(ECSA) 
AIC Kijabe Hospital  
Kenya 
 
January 2023 
