Laparotomy

Anatomy and Physiology

The abdominal wall encloses the abdominal cavity and protects the abdominal viscera. The layers of the anterior abdominal wall which may be encountered in a laparotomy include the following from superficial to deep: skin, subcutaneous fat, fascia of Camper, fascia of Scarpa, external oblique muscle, internal oblique muscle, rectus abdominis muscle, transverse abdominis muscle, pyramidalis muscle, transversalis fascia, and peritoneum.

The rectus abdominis muscles are two long vertical muscles on either side of the midline in the abdominal wall. The two recti are joined in the midline by the linea alba, a fibrous avascular plane that runs from the xiphoid process of the sternum superiorly to the pubic symphysis inferiorly. The lateral border of the two sides of this muscle creates a surface marking known as the linea semilunaris. This muscle is divided by fibrous intersections that join the linea alba to give the impression of the well-known six-pack. The rectus abdominis attaches to the pubic crest and inserts into the xiphoid process and costal cartilages of ribs 5, 6 and 7. It is considered a flat muscle which compresses the abdominal viscera and stabilizes the pelvis during movements such as walking. It is innervated by the thoracoabdominal nerve supplied by nerve roots T7-T11.

The pyramidalis, as the name suggests, is a small triangular muscle. It is found superficially and inferior to the rectus abdominis attached to the linea alba and has its base on the pubis bone.

The rectus abdominis and pyramidalis muscles are enclosed in the rectus sheath which is formed by the aponeuroses of the external oblique, internal oblique, and transversus abdominis. The rectus sheath consists of an anterior and posterior component.

• Anterior rectus sheath – made from the aponeuroses of the external oblique and half of the internal oblique.

• Posterior rectus sheath – made from the aponeuroses of the external oblique and of half of the internal oblique.

However, there is no posterior rectus sheath below the arcuate line. This point is approximately midway between the umbilicus and pubic symphysis and therefore puts the transversalis fascia in direct contact with the rectus abdominis.

The blood supply to the abdominal wall can be considered a dual supply. The first supply consists of the inferior and superior epigastric arteries form the deep epigastric arcade, which is found between the rectus abdominis muscle and the posterior rectus sheath (also known as the retrorectus plane). The rectus muscle is supplied by perforating vessels which also branch off to supply the linea alba. The other main supply is the segmental arteries which arise from the aorta to supply the oblique and transverse muscles. These run between the internal oblique and transverse muscles. [2]

The thoracoabdominal nerve, the iliohypogastric and ilioinguinal nerves, and the ventral branches from the 5 to 12 thoracic nerves all contribute to the innervation of the abdominal wall.

Indications

 The indications for a laparotomy have significantly reduced in recent times since the advent of minimal access surgery. It is however important to note that access is key to any surgical procedure. In many situations, keyhole surgeries may be extremely difficult or even impossible as the risk of injuries to vital structures may outweigh the benefits of minimal access procedures. In these situations, whether emergency or elective, the more traditional laparotomy remains the mainstay. Broadly, these situations include multiple dense adhesions from previous surgeries or inflammatory conditions, grossly distended intestines in intestinal obstruction or massive ascites in patients with end-stage liver or cardiac disease. Emergency conditions, such as those for acute intraperitoneal bleeding, uncontrollable gastrointestinal bleeding, blunt or penetrating abdominal injuries, generalised intraperitoneal sepsis due to perforated gastrointestinal tract are still the most common indications for laparotomy[3]. Elective procedures that involve a large specimen, such as Pancreaticoduodenectomy, pancreatic or intestinal transplants are also indications for laparotomy.

Contraindications

The most important contraindication to note is the patient who is unfit for general anesthesia which will likely be due to a combination of factors including co-morbidities, sepsis, hemodynamic instability, and widespread metastatic malignant disease. The patient’s wishes are also very important as it is their right to say no to a laparotomy (no matter the indication) if they have the capacity to make that decision.

A thorough clinical evaluation and relevant radiological investigations are paramount as one should always high index of suspicion for medical conditions that may mimic acute abdomen thereby causing a false indication for laparotomy such as acute pancreatitis, hyperglycaemic crisis, gout, gastritis or urinary tract infection[4].

A prognostic predictor tool such as the P-POSSUM score may be helpful at times to assess the morbidity and mortality risks.

Equipment

The extent of instruments for a laparotomy can vary depending on the indication for the operation. However, to simply gain access into the abdomen, the following instruments are used:

• Scalpel (usually a 10 blade)
• Monopolar cautery
• Tooth forceps
• Abdominal packs/swabs
• Fraser-kelly clips
• McIndoe scissors
• Retractor
• Suction

Personnel

Key personnel usually present at a laparotomy include the surgeon, surgeon’s assistant, scrub nurse, anesthetist, anesthesist technician, operating department practitioner, and some theatre staff to act as runners in case more kit is required.

Preparation

The extent of the physical and emotional elements of preparation can vary depending on the purpose of the operation. For example, it would be optimal to involve cancer nurse specialists in the event of cancer to help with pre-operative counselling. In the emergency situation, it is important to speak to the patient’s next of kin (NOK)/loved ones, should the patient wish, to help strengthen the patient’s support network during the acute stressful time. Informed consent is also vital in preparing the patient and his/her relatives to what to expect and likely outcomes. If the patient is unconscious or lacks capacity, then a Consent Form 4 can be completed by the surgeon to act in the patient’s best interests. To complete a Consent form 4, the patient must have a documented mental capacity assessment and a close member of the family must be discussed with if possible. Children below the age of consent, require consent form 2 completed with the parent or guardian actually providing the legal consent[5].

Physical preparation varies somewhat based on the nature of the operation and whether it is an emergency procedure or a planned, elective operation.

The points to consider include the following:

• Hair removal from the abdominal wall
• Patient BMI – For those having a planned ileostomy in an elective setting, weight loss may be requested before the operation to improve the patient's anaesthetic suitability and reduce the distance the small bowel mesentery has to traverse to be bought to the skin without tension.
• Previous operative scars/deformities of the abdominal wall - A previous operation increases the extent of adhesions.
• Hernia presence
• In a planned setting, one would consider the effect of smoking and diabetic control on wound healing.
• To consider the positioning of a stoma site if appropriate – This is usually at a level where the patient can see it, access it easily, and not have it interfering with belts or skin folds. It should also ideally avoid the costal margin and umbilicus.
• A nasogastric tube in cases of obstruction/perforation or if anticipating a postoperative ileus
• Adequate fluid and electrolyte resuscitation
• Urinary catheter
• Intravenous antibiotics
• Crossmatching of units of blood products
•  Appropriate imaging, e.g. CT AP

Technique or Treatment

The following incisions are used for access into the abdominal cavity:

Midline/Median Approach

The most common procedure is the midline laparotomy where an incision is made down the middle of the abdomen along the linea alba. The size of the incision can be limited depending on the site of the pathology. For example, an upper gastrointestinal problem may not require a lower midline incision. However, the decision can always be extended lengthways to gain more access if needed. Some surgeons will curve their incision around the umbilicus; however, a more cosmetically pleasing technique includes retracting the umbilicus away from the midline using a Littlewood's clamp to keep the incision vertically straight. The incision is usually made with a scalpel, although cutting cautery is also an option for the skin cut. Then, coagulative cautery is used to dissect the subcutaneous fat and superficial fascial layers down to the rectus sheath. As the linea alba is where the aponeuroses converge, this is an avascular plane, and therefore muscle should not be encountered. Once dissected through the rectus sheath (anterior and posterior components), two Fraser-kelly clips can be applied to the peritoneum and lifted up. McIndoe scissors then cut between the clips which should allow access into the peritoneal cavity. The surgeon then sticks his/her fingers into the hole created and widens the incision in the peritoneum, taking care not to injure any underlying structures such as the bowel.

Paramedian Approach

This approach is similar to the midline approach; however, the vertical incision is made lateral to the linea alb to allow access to lateral/retroperitoneal structures such as the kidneys and adrenal glands. The linea semilunaris, which is the lateral border of the rectus, is usually the landmark used. The paramedian incision increases the possibility of muscle atrophy, hematoma, and nerve injury because it is more likely for the surgeon to encounter various vessels and nerves supplying the muscles of the abdominal wall.

Transverse Approach

As the name suggests, this approach uses a transverse incision lateral to the umbilicus (compared to the previous approaches which are vertical). This is a common approach as it causes least damage to the nerve supply to the abdominal muscles as it follows a dermatome, and heals well. The incised rectus abdominis heals producing a new tendinous intersection. An example of where this is used is in an open right hemicolectomy.

Pfannenstiel Approach

Pfannenstiel incisions are made 5 cm superior to the pubis symphysis in a curved transverse fashion to gain access to the pelvic cavity When performing this incision, care must be taken not to perforate the bladder as the fascia around the bladder is thin. Intestinal loops can also be commonly encountered here. This incision is commonly used in emergency cesarean sections as well as a site of extraction for pathological specimens that have been excised elsewhere within the abdominal cavity.

Subcostal Approach

This incision starts inferior to the xiphoid process and extends inferior and parallel to the costal margin. The incision should be at least two fingerbreadths below the costal margin to reduce the risk of post-operative pain and poor wound healing. It is used to access the gallbladder and liver when performed on the right-hand side and the spleen when on the left-hand side. If both left and right subcostal incisions are joined together in the midline, they form a rooftop incision.

Complications

Complications of a laparotomy can be site-specific or general but are usually influenced by factors at the time of the operation. As such, it can be classified as patient-related or operator-dependent and, of course, should take into account the operation itself. The following is a broad list of possible complications:

• Bleeding
• Infection
• Bruising
• Seroma/ hematoma
• Wound dehiscence
• Necrosis
• Incisional hernia
• Chronic pain
• Skin numbness
• Fistulation with underlying structures
• Raised intra-abdominal compartment pressure
• Damage to underlying structures
• Poor cosmesis

Clinical Significance

The term laparotomy implies a potentially major operation in most surgical circles, however, does not stipulate in the name what operation the patient will have after the major open incision is performed. With advances in minimally invasive surgery and robotics, an open cut is being utilized less often unless clinically indicated, such as in an emergency situation where access into the abdomen needs to be fairly rapid or where the intra-abdominal environment is not amenable to other techniques.[6] Thus it is imperative that the patient is appropriately resuscitated, electrolytes, and sepsis are managed, and that care is taken when making the surgical cut to minimize the insult on the patient’s physiology.[7][8][9][10]

Enhancing Healthcare Team Outcomes

Key personnel usually present at a laparotomy include the surgeon, surgeon’s assistant, scrub nurse, anesthetist, operating department practitioner, and some theatre staff to act as runners in case more kit is required. The operating room nurses are required to set up the instruments and do a pre and post count of sponges, needles and other equipment used during the procedure. In general, no patient should leave the operating room with missing sponges or needles. Every hospital has protocols that both nurses and surgeons need to follow to ensure that no unintended item is ever left inside the patient.