Preparation for open appendicectomy

• The patient will require a general anaesthetic and be positioned supine

• Prophylactic antibiotics are given to reduce the incidence of wound infection

• The patient should be draped to expose the right lower abdominal quadrant and allowing identification of the umbilicus and right anterior superior iliac spine (ASIS)

Incision for open appendicectomy

Classically the incision lies over McBurney's point; which is a surface marking 1/3rd of way along an imaginary line joining the right ASIS and the umbilicus. An incision is made perpendicular to this line. This is also known as a gridiron or McBurney's incision.

The Lanz incision is more commonly used now as it has a better cosmetic result. This incision is made horizontally over McBurney's point.

A lower midline incision should be considered in the middle aged or elderly patient or if the diagnosis is in doubt.

Tip: It is useful and also good practise to palpate the abdomen once the patient is anaesthetised and relaxed. This allows you to possibly identify an appendix mass and often the caecum can be palpated which aids the location of your incision.

Tip: For the exams - remember that McBurney's point is supposed to mark the base of the appendix, as the tip can lie in many places.

Procedure for open appendicectomy

After the skin incision the subcutaneous fat is divided down to the external oblique aponeurosis. And it is useful to clear the fat of the aponeurosis with a small swab at this stage.

An incision is made in the line of the fibres into the external oblique aponeurosis with a scalpel and extended with tissue scissors. Beneath this you will find the internal oblique muscle which is split with a pair of curved heavy scissors. The split can be enlarged with either your fingers or a pair of retractors. Peritoneum should now be visible. It can be picked by and tented by two small clips. The peritoneum is then opened by stroking with the belly of a scalpel blade. Ensure there is nothing adherent to the underlying peritoneum and extend the incision with scissors.

Made a note of any fluid released from the peritoneal cavity and if turbid then consider sending a culture swab.

In acute appendicitis it is very likely that the omentum will have migrated down to the right iliac fossa. This can be gently pushed away medially.

Probably the easiest method of finding the appendix is to first identify the caecum. If the caecum is not readily identifiable then find some small bowel and follow it back to the caecum. The taeniae on the caecum can then be followed down to the appendix. Attempted to deliver the caecum and appendix through the wound. If the appendix is very inflammed it will be adherent to surrounding structures. Pass your index finger down from the base of the appendix clearing and adhesions with gentle blunt dissection.

If at this stage you are unable to deliver the appendix then enlarge your incision by dividing the fibres of internal oblique. If necessary rectus can be divided too.

Once the appendix is delivered it should be held with a tissue holding forcep such as a babcock. The mesoappendix is then clipped and divided and the pedicles tied with an braided absorbable tie such as vicryl.

The base of the appendix is crushed with a heavy clip and the clip is placed slightly higher on the appendix. The safest method of dealing with the base is to suture ligate it. The appendix is then divided under the attached clip with a scalpel blade and the suture cut. The remaining suture can then be used to bury the stump with either a purse string or a 'Z' stitch. Now ensure that both the remaining suture and blade used are discarded as they are dirty.

The ceacum is gently placed back into the peritoneal cavity and any fluid sucked out. A washout can be performed although some argue that it just spreads the contaminated fluid around the whole abdomen.

Closure following appendicectomy

The edges of the peritoneum are identified and picked up with up to four clips. The peritoneum is then closed using a continuous 3/0 absorbable suture. The muscle fibres can be loosely approximated with some interrupted stitches. The external oblique defect must be securely repaired. This is done with a continuous 3/0 absorbable suture.

A local anaesthetic agent can now be infiltrated to provide postoperative pain relief.

Skin can be closed with a continuous subcuticular absorbable suture. If the wound has been highly contaminated then consider closing with an interrupted suture or skin clips.

Postoperative Care

• Routine observation of heart rate, blood pressure and temperature

• Allow free fluids orally and full diet the next day

• DVT prophylaxis should be commenced immediately

• Two further doses of the antibiotic used on induction can be given postoperatively

Other points to note

• If the appendix looks macroscopically normal it should still be removed. Patients with a right iliac fossa scar will be assumed to have had a appendicectomy by other medical staff. Additionally, 15% of macroscopically normal appendixes prove to be acute appendicitis under microscopy.

• If macroscopically normal, then do remember to check for other causes, such as mesenteric adenitis, Meckel's diverticulitis, ovario-tibular pathology or a sigmoid diverticulitis.

• If an appendix mass (abscess) is present and the appendix can not be found then place an abdominal drain to the mass and close. An interval appendicectomy can be performed at a later date.

• Occasionally you will find a right colon carcinoma or terminal ileitis. This require a right hemi-colectomy to be performed and senior help should be obtained if required.