7. GI STAPLING TECHNIQUES

Introduction

Until now in the course you have been using suturing techniques in different situations, however the development of mechanical stapling devises means that there are alternative ways of performing many anastomoses.(13) These are not necessarily novel and have been in use for many years (Figure 7.1).

Figure 7.1 'Murphy's Button' devised in 1892 as an early mechanical device for GI anastomoses

The few trials that have been conducted have not shown any benefit in terms of outcome for either a sutured or a stapled anastomotic technique.(14-16) There is no doubt, however, that stapling techniques are quicker to perform, particularly in situations where access is difficult such as a low colorectal anastomosis or an oesophageal anastomosis. Stapling should, therefore, be part of the modern surgeon's armoury and you should be equally adept with a staple gun as with a needle holder and suture.

Historical principles

There are many types of stapling devices that may be used on the bowel, but these may be broadly categories into those which:

• produce a linear staple line (Figure 7.2)
  
  

  Figure 7.2 Linear stapling device

  
  
• cut between two linear staple lines (Figure 7.3)
  
  

  	Figure 7.3 Linear stapler and cutting device
  	Note the two cartridge sizes

  
  
• cut and result in a circular staple line (Figure 7.4).
  
  

  Figure 7.4 Circular stapling device

In all cases it is essential to be sure of what you wish to achieve with the mechanical stapler and to then select the appropriate instrument. In many cases there are different sizes of instrument and the correct one must be chosen for the correct procedure. Similarly, the size of the staples may be different or may be changeable depending upon the instrument and the manufacturer - clearly this must be gauged by the surgeon, again depending upon the task in hand.

Because the actual anastomosis is performed with a mechanical device instead of the individual placement of sutures, it does not mean that you afford to be any less meticulous in the setting up of the anastomosis and in the performance of the procedure. You must go through exactly the same steps as have been discussed in the previous chapters.

A stapled anastomosis will fail in the same way that a sutured anastomosis will, ie if the bowel ends are not well vascularised, are under tension or there is a technical failure in the performance of the anastomosis.

Clearly the application of each of these points will be dependent upon the site of the anastomosis, ie whether this is a small bowel, a colorectal or oesophago-gastric anastomosis. For the purposes of this course we will describe the reconstruction following a total gastrectomy using a stapling technique. The exposure and assessment of the situation are well-described elsewhere and will not be discussed further.(17) Instead, emphasis will be given to stages of the reconstruction in which stapling devices are frequently utilised.

Division of the duodenum

The duodenum is divided at least 2 cm distal to the proximal border of the tumour. Care should be taken in the mobilization of the duodenum to ensure that the small vessels between the first part of the duodenum and the pancreas are ligated or coagulated as these may bleed profusely. When the site of the duodenal transection has been decided upon, ensure that the common bile duct will not be compromised.

A clean and reliable method of transection of the duodenum is to use a linear cutting stapler such as the PLC (Ethicon, UK) or GIA (Autosuture, UK) (Figure 7.5).

Figure 7.5 Division of the duodenum

The advantage of this technique is that the duodenum is divided cleanly and both the gastric and duodenal margins are sealed with a row of staples. Many surgeons will then invert the duodenal stump using a continuous 3/0 PDS suture although this may not be necessary.

Formation of a Roux-en-Y loop

There are many ways of reconstruction after a total gastrectomy but the use of a Roux-en-Y loop is perhaps the most widely utilised. It has the advantage of providing a loop of jejunum without any tension on the anastomosis and at the same time reducing the risk of bile reflux into the oesophagus. The preparation of the jejunal loop has to be undertaken with the utmost care always ensuring that the vascularity is maintained. There are certain technical aspects to this:

• The division of the peritoneum over the mesentery using a scalpel may aid in the visualisation and subsequent division of vessels (See Figure 3.1).
  

  Figure 3.1 Division of the peritoneum covering the mesentery facilitates visualisation of the underlying vessels.

  
  
• Care must be taken in the application of ligatures to vessels such that the feeding vessels to the bowel are not compromised. The use of Lahey forceps to place the sutures and then tying in continuity helps in this regard (Figures 7.6).
  
  

  Figures 7.6 Ligation of mesenteric vessels in continuity

  
  
• Where a long loop of jejunum is required and several arcades of vessels have to be ligated it may be useful to apply a soft clamp to the vessels so that the vascularity of the bowel can be assessed prior to any permanent ligation and division.

Once the mesentery has been divided, the jejunum is divided. This is conveniently performed using a short linear cutting stapling device (Figure 7.7), the smaller size of staple being favoured for most cases (blue cartridge). After firing the stapler the jejunum is cut and sealed. However, the ends must be inspected to ensure that there is good vascularity or, alternatively, they are not bleeding.

Figure 7.7 Division of the jejunum

The distal limb of the jejunum is now brought retro-colically to the level of the eventual oesophago-jejunal anastomosis.

Oesophago-jejunal anastomosis

This can be a very difficult anastomosis to perform as access may be difficult, a long segment of jejunum may be required, and its vascularity may, therefore, be difficult to maintain so the oesophagus may not be well vascularised. Care must be taken in your set up and preparation to circumvent these problems. The anastomosis can be performed using a sutured technique but a stapled anastomosis will be described in this situation.

The site of the anastomosis should be on the anti-mesenteric border of the jejunal loop at a site that easily reaches to the divided end of the oesophagus, approximately 2-5 cm away from the divided end of the jejunum.

Prior to the division of the oesophagus stay sutures should be placed at the right and left sides of the oesophagus. After division, further stay sutures placed anteriorly and posteriorly will allow the anvil of a circular stapling device to be inserted into the oesophagus (Figure 7.8).

Figure 7.8 Insertion of the anvil of a circular stapler into the oesophagus

Care must be taken at this stage to ensure that the anvil is of the appropriate size and that the oesophagus is not split/torn by its insertion. A purse string suture is inserted around the circumference of the oesophagus and tied snugly against the anvil (Figure 7.9).

Figure 7.9 A purse string suture has been tied around the anvil of a circular stapler in the oesophagus

Attention is now focused on the jejunal loop. At a distance 45-50 cm proximal to the intended site for the anastomosis an enterotomy is made and the circular stapling gun is inserted into the jejunum (Figure 7.10).

Figure 7.10 A circular stapling device is inserted into the jejunum

It should be well lubricated and gently advanced, concertinaing the jejunum over this until the chosen point for the anastomosis is reached. The jejunum is held taught over the end of the gun and an assistant advances the spike through the bowel wall (Figure 7.11). Care is taken not to tear the jejunum and often a small incision over the advancing spike is helpful.

Figure 7.11 The spike of a circular stapling device is shown emerging through the anti-mesenteric border of the jejunum at the proposed site of an oesophago-jejunal anastomosis

Different staplers have different mechanisms but the anvil and stapler should be joined together (Figure 7.12).

Figure 7.12 Connection of the anvil to the stapling gun in preparation for an oesophago-jejunal anastomosis

Now the stapling gun should be tightened so that the jejunum and the oesophagus are approximated. Ensure that the jejunum lies well, ie untwisted and with no other tissues interposed between the oesophagus and jejunum. Most devices will have an indicator as to when the anvil and stapling gun are close enough together; only when this is reached can the gun be fired. After the stapler has been fired it should be loosened (usually two full twists of the tightening mechanism). The whole stapler is now gently rotated and then removed. Inspection of the cartridge should reveal two complete circles of jejunum and oesophagus. The staple line should also be inspected to ensure that it is complete.

Jejuno-jejunostomy

The final stage of the reconstruction is to join the proximal divided jejunum to the jejunal loop. To ensure that there is adequate biliary diversion this should be 45-50 cm distal to the oesophago-jejunostomy. The enterotomy site used for the insertion of the staple gun is a suitable site for the anastomosis. The proximal jejunal loop should be brought to lie adjacent to the existing enterotomy. It may be useful to insert stay sutures both at the site of the enterotomy and distally. An enterotomy is made on the proximal loop of jejunum and a linear stapling device inserted into the two limbs of jejunum (Figure 7.13).

Figure 7.13 Side-side jejunostomy using a linear cutting stapler

Care must be taken to ensure that the two components of the stapler are correctly fitted back together and that the jejunum is held up against the proximal end of the stapler - thereafter the stapler can be fired. After removal of the stapler the enterotomy wounds can be closed with a sero-submucosal continuous PDS suture as described previously.