Right Hemi-Colectomy

SECTION 5.00 INSPECTING THE PERITONEAL CAVITY

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5.01 INSPECT THE PERITONEAL CAVITY

This assessment considers a malignant tumour of the caecum or right colon, but can be applied in large part to Crohn's disease and other rarer conditions.
An easily remembered approach is to use an acronym TNMO.

      TUMOUR
      NODES
      METASTASES
      OTHER PATHOLOGY

5.02 ASSESSING THE TUMOUR - READ ON

5.03 CHECK THE PRESENCE OF A TUMOUR

A tumour is usually palpable as a hard mass in the wall of the right colon.
A benign or malignant polyp in the right colon may not be palpable through the bowel wall. You will need to rely on colonoscopy or radiological findings for the position of the lesion.

5.04 CHECK THE SIZE

A typical tumour of the right colon is a bulky mass. This is partly due to the diameter of the right colon being large. The tumour is less likely to encircle the bowel and cause an obstruction than in the narrower left colon.

5.05 CHECK THE AMOUNT OF LOCAL SPREAD

This will determine the resectability of the tumour.
Spread around the circumference of the bowel, causing obstruction.
Spread up or down in the bowel wall, dictating how much bowel needs to be removed to ensure clear resection margins. This is conventionally about 15cm beyond the macroscopic tumour margin.

It may spread through the wall of the bowel in any of 4 directions - medial, lateral, posterior or anterior.

5.06 CHECK THE MOBILITY OF THE TUMOUR

If the tumour feels mobile when held in the hand,
It is unlikely to have spread into local structures.
It is very likely to be resectable.
More than 60% of tumours are mobile and resectable without major additional surgery.

5.07 CHECK THE ADHERENCE TO LOCAL STRUCTURES

Anterior spread
The surrounding peritoneum.
This implies transcoelomic spread as well as local spread.
Omentum.
Part of the greater omentum may be adherent to the tumour or seal off a perforation. It should be removed in continuity with the tumour.
The omentum attached to the right colon is removed as part of an en bloc procedure, mainly because of the lymph nodes embedded in it.
Small bowel.
There may be anything from a marginally adherent loop of small bowel to a mass of small bowel, usually ileum, fixed to the tumour.
Large bowel.
A low caecal tumour may be adherent to the sigmoid colon with the chance of fistula formation.
Lateral spread
Lateral abdominal wall.
There may be an abscess in thickened tissue in this area.
Medial spread
Mesocolon.
There is usually lymph node spread in addition.
Posterior spread
Ureter.
If the ureter is affected by the tumour, it is more likely to be compressed by the tumour than invaded by it.
Nevertheless, the surgeon should be prepared to divide the ureter and even remove the right kidney if required.
The left kidney must always be assessed before embarking on this surgery.
Right kidney.
The right kidney may be directly invaded by a tumour in the hepatic flexure of the colon. It is more often the site of hydronephrosis from ureteric compression.
It may need to be removed as part of an en bloc resection, or for ureteric invasion.
Duodenum.
The third part of the duodenum lies directly behind the hepatic flexure of the colon. It should be sought in every right hemicolectomy.
It may be compressed or invaded by a tumour of the hepatic flexure. If invaded, it needs to be resected with an appropriate bypass such as a gastro-jejunostomy.
Vena cava
The vena cava is an important posterior relation to the right colon. It needs to be avoided when mobilising the right colic vessels. However it is rarely invaded in otherwise operable cases of carcinoma of the right colon
If necessary, parts of the vena cava can be resected and repaired with a vein graft

5.08 CHECK THE DEGREE OF OBSTRUCTION

This implies circumferential spread. It is most likely in a tumour affecting the narrow ileo caecal area. The presentation will be that of a low small bowel obstruction, often incomplete at first.
If the tumour stenoses the colon more distally and the ileo-caecal valve is competent:
There will be a closed loop obstruction presenting as an emergency.
This will be much more rapid than if the ileo-caecal valve is incompetent. Then there is only gradual distension of large and then small bowel through the ileo-caecal valve.
It is more acute than an ileo-caecal obstruction, with perforation of the caecum possible within a matter of 4-6 hours or so.
Distension of the small bowel due to obstruction may help match the diameter of the small bowel to that of the undistended distal large bowel for the anastomosis.
However the distended small bowel is likely to be oedematous, fragile and
hypoxic, making the anastomosis more hazardous.

5.09 CHECK FOR FAECAL LOADING PROXIMALLY AND DISTALLY

Faecal loading proximal to a right colon carcinoma is not a problem, because the faecal matter will be removed with that part of the bowel.
It is a main indication for performing an extended right hemicolectomy for a tumour in the left colon.
Faecal loading distal to a right colon tumour is not directly related to the malignancy, but is a source of damaging back pressure on an ileo colic anastomosis.
Milking the faecal matter down as far as possible into the sigmoid colon and rectum is worthwhile.
Consider a gentle anal sphincter stretch in a patient under 70 years.
A postoperative enema is worth considering.
Review preoperative washout procedures.

5.10 CHECK FOR LYMPH NODE SPREAD

Lymph node spread indicates an increased chance of death from distant metastases.
In addition, invaded lymph nodes may cause morbidity and mortality directly by obstructing bowel or the biliary system at the porta hepatis.
Look for enlarged nodes:
    The mesocolon.
    The paraoartic region.
    In the porta hepatis.
Enlarged nodes are not necessarily invaded with tumour. Reactive nodes are common, as are nodes enlarged secondary to abscess formation.

5.11 CHECK FOR METASTASES

In the abdominal cavity, as in the whole body, start at the top and work your way steadily downwards.
Take biopsies by excision or with needles such as Trucut needles to confirm the histology. Fat necrosis and scar tissue may mimic malignancy.

5.12 CHECK FOR LIVER METASTASES

Examine visually and by palpation both lobes of the liver.
You may not be able to feel metastases deep in the liver substance, which have been demonstrated on ultrasound or CT scans.
You may feel granular metastases on the liver surface, which are often not detected by imaging.

5.13 CHECK FOR PERITONEAL AND OMENTAL METASTASES

On the peritoneal surface, these are usually granular, but may coalesce in folds and creases in the peritoneum.
Omental metastases are often gritty or lumpy. They may reach 10cm or more in diameter.

5.14 CHECK FOR BOWEL METASTASES

These are usually peritoneal metastases which can be sufficiently large or stenosing to cause or threaten obstruction, particularly in the small bowel.
Occasionally there is a diffuse infiltration of the mesentery.
Palpate the whole length of the small bowel.

5.15 CHECK FOR OTHER TUMOURS IN THE LARGE BOWEL

Palpate the whole length of the large bowel to exclude previously undetected primary tumours.
Add resection of any such lesion to the planned right hemicolectomy.

5.16 CHECK FOR SKIP LESIONS IN CROHN'S DISEASE

In Crohn's disease, examine the whole of the alimentary tract from the stomach to the rectum for skip lesions.
They are reddened, oedematous thickened patches on the bowel wall.
They may extend all round the circumference of the bowel and involve 2-10cm of the wall or more.
There may be more than one.
In severe cases, most of the small and large bowel may be affected.

5.17 CHECK FOR OVARIAN AND PELVIC METASTASES

Krukenberg tumours of the ovary are found in perhaps 5% of female patients with carcinoma of the large bowel.
In fact, a benign ovarian swellings are also relatively common in this age group.
Seek gynaecological assistance in further management.
If gynaecological advice is not available:
Perform an oophorectomy for a mobile ovarian tumour and await histology in the postoperative period.

5.18 CHECK FOR OTHER PATHOLOGY IN ABDOMEN AND PELVIS

Common findings include stones in the gallbladder, symptomless aortic or iliac aneurysms, uterine fibroids.
Usually simply noting the findings at this stage is all that is required.
Resist the temptation to embark on extra procedures for non urgent conditions.

5.19 CHECK FOR ADHESIONS OR HERNIAS AROUND ANY STOMA

If a caecostomy or ileostomy has been performed:
Check whether the peritoneal space lateral to the stoma has been closed. This will need to be freed off later in the operation.
Check that there is no herniation of omentum or small bowel alongside the stoma. Again, this will need to be freed off later.