This is a technical description of how I do a dunking anastomosis for reconstruction of a pancreaticoduodenectomy in a patient with a soft pancreas and/or very small duct. The drawings are beyond my ability with powerpoint so apologies for the hand drawn cartoons.
The pancreatic anastomosis whether it is to the stomach or the jejunum is generally considered (with good reason) to be the Achille’s heel of the pancreaticoduodenectomy (Whipple) procedure. Published leak rates vary between centres from as low as 3% and up to 15% or more. There are so many definitions of pancreatic leak that an international consensus conference was established to try to agree a uniform definition!
Over the years I have experimented with all of the major types of pancreatic anastomosis for reconstruction after pancreaticoduodenectomy. My choice of pancreatic anastomosis depends on the size of the duct and the consistency of the pancreas. If the duct is dilated and the pancreas is firm, I would choose to do a 2 layer pancreaticojejunostomy with a continuous 5/0 pds duct to mucosa anastomosis under magnification for the internal layer. If the pancreas is very soft and the duct ❤ mm or invisible, I prefer to do a dunking anastomosis. As it happens we have done 3 such anastomoses in the past week alone and so I thought I would describe my personal tips and hints for doing this.
Indication- soft pancreas pancreatic duct<3mm (some people actually use this anastomosis all of the time and so it is fine for firm pancreases too although not my choice). Consider in duodenal cancer, small neuroendocrine cancers, trauma or situations where there is no duct dilatation and a soft pancreas.
Let us assume that you have fully mobilised the head of the pancreas, divided the duodenum or stomach proximally and the jejunum distally and just need to divide the neck of the pancreas. I use 3/0 PDS sutures to place a haemostatic suture on the left side of the tunnel in front of the portal vein at the upper and lower border of the pancreas. These sutures are about 5mm from the intended line of transection of the neck of the pancreas and are quite deep taking around 7 mm of pancreas on each side. Tie these sutures in their middle and leave both needles on. Place similar sutures on the right side of the tunnel but the needles don’t matter here as the head of the pancreas is coming out.
Divide the neck of the pancreas complete the posterior dissection and remove the specimen. You should be left with the tail of the pancreas and your two 3/0 sutures looking something like this.
Now you need to mobilise the tail of the pancreas carefully off the splenic vein for 1-1.5 inches or 2.5-3.5cm. Take the small feeding vessels that often enter the upper and lower border of the neck of the pancreas here (you will not compromise blood supply to the tail which comes from the splenic artery). You can then lift the neck of the pancreas gently away from the splenic vein.
Next bring your loop of jejunum up to the region of the cut surface of the pancreas. I usually take the jejunal loop around behind the superior mesenteric artery where the duodenum was previously. Excise the staple line across the whole length of the jejunum.
Now we are set up to start the anastomosis. Take a 4/0 PDS (some people use prolene) double ended suture and starting at the upper border of the pancreas as far distally as you have mobilised. What I do is to create a horizontal mattress suture taking the pancreas capsule on one side and the serosa of the edge of the jejunum on the other, alternating between the two. The capsule and the duct are really the only two parts of the pancreas that have any tensile strength and this utilizes the capsule to create an outer layer.
I tend to do this as a parachuted anastomosis with a gap between the pancreas and the jejunum. When you have finished the backwall reaching the lower border of the pancreas spray some saline or water on the sutures as you gently pull both ends to move the jejunum up to the capsule of the pancreas. Be very careful and only pull on sutures coming through the jejunal wall or you will risk tearing the soft pancreas.
Your anastomosis should now look something like the picture above. Now take the first of the upper border 3/0 PDS sutures and pass them down the lumen of the jejunum for about 3 cm and exit from inside to outside the jejunum. Take the second and exit around 4-5 mm in any direction from the first suture. Now do the same with the two lower border 3/0 PDS sutures. Then ask your assistant to take the anterior edge of the jejunum with a pair of Debakey forceps and pull in the direction of the tail so that the cut end of the pancreas passes into the jejunal loop as you tie both of the 3/0 PDS sutures to the other of its pair.
Once you have done this the pancreas will lie in the jejunal loop and you then need to complete the anterior layer by taking the upper border 4/0 PDS suture and continuing the horizontal mattress suture between the pancreatic capsule and the serosal edge of the jejunum to complete a circle around the tail of the pancreas.
When you have finished and tied off the 4/0 suture your anastomosis should look like the picture below and you should be able to feel the cut edge of the pancreas 2.5-3 cm inside the jejunal loop.
You now need to complete the other anastomoses either on to the same loop or onto a separate Roux loop.
Practical tips (some reiterated).
1. some people prefer to use prolene rather than PDS.
2. Make sure you mobilize an adequate length of neck/body of pancreas and clean it up well from attached tissue.
3. Keep shallow horizontal bites on the pancreatic capsule and dont try and pull too tight or from the pancreas side of the anastomosis.
4. Tie the large 3/0 PDS sutures snug but agin not too tight or you will risk tearing the pancreas.
5. When completing the anterior wall get your assistant to pull up the jejunum as you increase tension along your suture line so that you avoid tearing out your sutures.
I did not invent this anastomosis and there are lots of subtle variations to this all of which I am sure work. This anastomosis works very well for me with the soft pancreas and I hope it will suit you too!