Yesterday, I think I came across my favourite General Surgical operation yet. An open right hemicolectomy.
I have had the pleasure of scrubbing into a variety of operations so far, however, it was the open right hemicolectomy yesterday that really made me think:
“wow this is awesome”.
It was just so visual; bowel was spilling out of the abdominal wall, a huge tumour was invading through the colonic wall, all the anatomy clear as day in all it’s g(l)ory. So far, I had only assisted in the laparoscopic version of this operation, where the anatomy was much more difficult to fully appreciate, as it all appeared 2-dimensional and I didn’t have any manual feedback from handling the bowel. In this open case, once the midline laparotomy opening had been created, the bowel was mobilised and brought up to the skin, at which point the omentum was reflected back and the transverse colon was exposed, along with the rest of the large and small bowel. I’ll be honest, I really struggled to get my head round the whole anatomy of the greater and lesser sac during my revision for the MRCS part A as it’s difficult to appreciate on Google Images. Even YouTube videos just about made it digestible, yet as soon as I’d close the video, the knowledge would leave my head. Nevertheless, I realised my appreciation of anatomy and opportunities to see open surgery such as this really help consolidate all the time spent trawling through Google Images trying to recreate a 3D structure from 2D information.
So, what is a hemicolectomy and what does it entail?
The first port of call is to break down the name:
Hemicolectomy = hemi (half) + col (colon) + ectomy (removal) = removal of a portion of the colon.
A right hemicolectomy, as in the case for which I scrubbed in, therefore indicates the resection (aka surgical removal) of the right half of the colon. This comprises the ascending colon, including the caecum, and maybe some transverse colon (if most/all of the transverse colon and terminal ileum is resected then it’s referred to as an extended hemicolectomy). It is usually undertaken to excise a tumour of the right colon, including caecal cancer, or inflammatory bowel disease which affects the terminal ileum such as Crohn’s disease.
A rough overview of an open right hemicolectomy is as follows:
- Midline laparotomy incision. This incision goes right through the linea alba, in the middle of the rectus sheath – this avoid disruption to the rectus sheath and ensures good healing. It provides excellent access to the contents of the abdominal cavity and is the main incision used for major open intra-abdominal surgery such as this.
- Mobilisation of the ascending colon. This is done by detaching the ascending colon from its anterior peritoneal attachments. It is a retroperitoneal structure and so care needs to be given to adjacent structures such as the right kidney just under the hepatic flexure and the duodenum. The duodenum tends to lie posteromedially to the ascending colon but can easily be brought up with the ascending colon when it is mobilised, rendering it vulnerable to injury.
- Detachment from mesentary. Once the ascending colon has been mobilised from its peritoneal attachments, some careful dissection takes place to detach the colonic segment from the mesentary. The appendicular artery is ligated and the pedicle of the ileocolic artery is cautiously located.
- Detachment from omentum. Now, this bit is pretty cool. The omentum is flipped up onto the skin overlying the ribs and sternum to expose the anteroinferior surface of the transverse colon, along with the entirety of the abdominal contents below this level. This forms the best visualisation of the abdominal cavity, as the tissue is fresh, unlike cadaveric dissection where literally everything is a unique shade of pinky brown. The omentum is a bright yellow and the large bowel is easily discernible from the small bowel due to the obvious haustra and taeniae coli. Anyway, back to the omentum. The posterosuperior portion of the omentum, just adjacent to the point of attachment to the transverse colon is opened in order to mobilise this colonic segment. The inferior portion of the transverse colon is also dissected away from the mesentary.
- Ileocoloic anastamosis. Once both the ascending and transverse colonic segments are detached from the mesentary and omentum (only for the transverse colon), the pedicle is tackled. The artery is ligated from as far back as is safe to do so without compromising mesenteric blood flow. Once this is complete, the ascending colon is now free. Small incisions are made in the terminal ileum and the transverse colon. These incisions are where the jaws of the linear cutting stapler are placed prior to anastamosis. Any remaining bits of fat are stripped away from the bowel segments which are to be anastamosed and the staple jaws are brought together with the bowel segments lying side-by-side. The blade slices through and the staples click into place with one swift, smooth and satisfying motion of the linear cutting stapler trigger. Another staple line is then formed perpendicular to the side-by-side staple anastamosis, to separate the resectable portion of bowel from the anastamosed portion of bowel.
- Closure. Finally, the anastamotic staple line is reinforced and buried with hand sewn sutures. The abdominal cavity is thoroughly washed using water – this ensures a hyperosmolar gradient between any remaining tumour cells and the wash causing additional tumour lysis. A drain is placed in the pelvic cavity, i.e. the dependent portion of the abdomen where an intra-abdominal collection will usually form should an anastamotic leak occur. The bowel is replaced in the abdominal cavity, careful to ensure proper alignment of the bowel to avoid any twists, and the midline laparotomy wound is closed using Jenkin’s rule*.
*Jenkin’s rule is the principle to which the closure of the abdominal wall for any midline laparotomy wound should adhere. The suture must be 4 x the length of the wound. Bites are taken continuously with an even spacing of 1cm. Each bite must be 1cm of the wound edge. In this case, we used size 1 looped Polydiaxanone suture (PDS).
So, all in all, this was a lengthy but high yield educational case which enabled me to consolidate a lot of the abdominal anatomy I have learned over time. I would say it is definitely worth scrubbing into and just being curious about what you see. Reading about it afterwards and recalling the anatomy, even doing some teaching if possible, makes the knowledge retention so much more effective.
Vasudev Zaver 