SURGICAL INCISIONS

An incision is a cut made into the tissues of the body to expose the underlying tissue, bone, or organ so that a surgical procedure can be performed. An incision is typically made with a sharp instrument, such as a scalpel that leaves the skin and tissues with clean edges that are able to heal well. Incisions can also be made with an electrocautery tool, which uses heat to both cut and cauterize at the same time, which can dramatically minimize bleeding during a procedure.

An incision typically goes through the skin, fat, the underlying tissue, and often through muscle in order to allow the surgeon to access the surgical site. Incisions can also expose bone, which may also be cut, depending upon the nature of the procedure.

An incision is much deeper than it appears on the surface. This is why an incision may appear to have healed on the surface in only a week or two but can take months to reach full strength as the underlying muscle and tissues continue to heal. It is also why a surgeon may give you restrictions to not lift anything heavy that last well beyond when the wound appears healed. 

Incision Size

A traditional "open" incision is a large incision used to perform surgery. Typically at least three inches long but may be much larger, varying from surgery to surgery and the severity of the problem. This allows the surgeon enough room to work and see the area that is being worked on and to insert the necessary surgical instruments to perform surgery. An incision may be enlarged during surgery in order to give the surgeon more room to work. For example, when a patient is having gallbladder surgery, a small incision may initially be made. If the surgeon discovers that the gallbladder is very large and full of gallstones, the incision may be made larger so that it is large enough for the gallbladder to be removed.

Once the operation is over, surgical excisions can be closed by sutures, staples, steri-strips, tissue glue, or a combination of these agents. The wound can be covered in a protective dressing and kept dry for a few days, before normal washing can resume. Non-absorbable sutures or staples must be removed; the time when they are removed may vary depending on the site and indication of the closure.

Choice of Incision

The choice of the incision depends on:

• the type of surgery
• the organ to be exposed
• whether speed is an important factor (e.g. a fancy incision is inappropriate if the patient is bleeding to death from a intra- abdominal catastrophe)
• the build of the patient
• the presence of previous abdominal incisions (which may themselves be the site of an incisional hernia)
• the experience and preference of the surgeon.

1. A serious emergency (e.g. ruptured abdominal aortic aneurysm, closed abdominal injury) should be approached through a midline incision because it gives rapid access and can be enlarged to the whole length of the abdomen in a matter of seconds.
2. A subcostal (Kocher) incision gives excellent access for open biliary surgery in the obese patient with a wide subcostal angle. However, this incision has no advantage over the quicker and easier to perform upper midline incision in the skinny patient with a narrow sub- costal angle.
3. The Pfannenstiel incision is a beautiful cosmetic procedure for elective pelvic surgery (including open access to the prostate), but is time-consuming.
4. A lower midline incision is needed for an emergency Caesarean section (where minutes may be crucial for baby and mother). The surgeon must also be sure of the pathology before performing this approach. Close the Pfannenstiel and start again with a lower midline if the ‘pelvic mass’ proves to be a carcinoma of the sigmoid colon.

Abdominal Incision

Opening the abdomen is the essential preliminary to the performance of a laparotomy. A correctly performed abdominal exposure is based on sound anatomical knowledge.

The abdominal cavity is an ovoid space bounded cephalad by the diaphragm and inferior thoracic margin, caudally by the pelvic brim, posteriorly by the lumbar spine along with quadratus lumborum, psoas major and iliacus, and anterolaterally by the retaining musculature of the abdominal wall. The muscles of the abdominal wall play a major role in supporting ventilation, forcing the diaphragm cephalad in order to increase intrathoracic pressure to aid expiration, and allowing it to contract into the abdomen to decrease pressure for inspiration.

Within the abdomen lie the majority of the digestive tract and associated structures such as the liver, biliary tree, pancreas, kidneys and ureters. 

Anatomy of the Abdominal Wall

The lateral abdominal walls are formed by a triad of muscles: the external oblique (E.O), with its fibres running inferomedially like the fingers of the hands placed into the front pockets of one’s jeans; the internal oblique (I.O) with its fibres running orthogonally to its external relation, and transversus abdominis (T.A) with its horizontal fibres. Superficial to the external oblique lies Scarpa’s membranous fascia, Camper’s subcutaneous fatty layer, and the skin. Deep to transversus abdominis, the transversalis fascia encircles the preperitoneal fat and parietal peritoneum.

Incisions through the anterolateral wall will, therefore, breach the following structures:

• Skin
• Subcutaneous fatty layer
• Membranous fascia
• External oblique
• Internal oblique
• Transversus abdominis
• Transversalis fascia
• Preperitoneal fat
• Parietal peritoneum

As the fibres of the lateral abdominal wall muscles progress medially they give rise to fibrous sheets of tissue known as aponeuroses, allowing a far wider area of insertion than would be achievable with the typically round tendons seen on muscles of the appendicular skeleton. The internal oblique is unique in that its aponeurosis divides into an anterior and posterior leaf, the relevance of which will become clear later. These aponeuroses combine and interdigitate in such a way as to invest the paired longitudinal rectus abdominis muscles, forming the anterior midline structure known as the rectus sheath.

The rectus sheath

The paired rectus abdominis muscles originate from the anterior bony pubic bones toward the midline and run cephalad to insert onto the xiphisternum and costal cartilages of ribs 5-7. They derive their blood supply from the superior and inferior epigastric arteries from the internal thoracic and external iliac arteries respectively, and their innervation from the anterior rami of spinal nerve roots T7-T12.

The rectus sheath may be considered as having three distinct sections:

1. For most of the length of the paired recti, the anterior sheath is formed by the external oblique and anterior leaf of the internal oblique aponeuroses. The recti are interrupted by three paired tendinous intersections anchoring them to the anterior sheath, broadly found close to the xiphisternum, at the level of the umbilicus and then halfway between the two.

The posterior sheath is formed by the posterior leaf of the internal and the transversus abdominis aponeuroses and bears the superior and inferior epigastric arteries and their anastomotic network. The aponeurotic components of the sheath interdigitate in a thickened fibrous midline raphe between the two recti known helpfully as the linea alba (‘white line’). An elastic defect in this raphe may allow the fascia to stretch and abdominal contents to bulge forward through the resulting divarication of the recti. This produces a distinct ridge in the midline on increasing intra-abdominal pressure that is often mistaken for an epigastric hernia.

Point defects in the aponeurotic intersections of the linea alba may facilitate the development of epigastric hernias, which often simply contain preperitoneal fat but are often disproportionately painful for their size owing to their high tendency to strangulate.

2. There is no posterior sheath above the level of the costal margin, as the recti remain covered anteriorly by the external oblique aponeurosis and insert directly onto the underlying costal cartilages.

3. Roughly one third to halfway between the umbilicus and the pubic symphysis lies the arcuate Line (of Douglas), which is the point at which the posterior elements of the sheath perforate to join the anterior sheath and leave the thickened transversalis fascia in direct contact with the rectus muscles. The sheath is bounded laterally by the Linea Semilunaris, which is the longitudinal margin at which the internal oblique aponeuroses bifurcate to form anterior and posterior leaves. Defects in the integrity of the internal oblique may give rise to the formation of Spigellian Hernias, allowing protrusion of the peritoneal sac into the rectus sheath. On examination, the patient may have a palpable lump close to the lateral border of the rectus sheath, commonly at the level of Douglas.

Abdominal Incisions

Midline Incision

The most common incision for laparotomy is the midline incision, a vertical incision which follows the linea alba. Midline incisions are particularly favoured in diagnostic laparotomy, as they allow wide access to most of the abdominal cavity. The midline abdominal incision has many advantages because it:

• is very quick to perform
• is relatively easy to close
• Is virtually bloodless (no muscles are cut or nerves divided).
• affords excellent access to the abdominal cavity and retroperitoneal structures
• can be extended from the xiphoid to the pubic symphysis.

The upper midline incision is placed exactly in the midline and extends from the tip of the xiphoid to about 1 cm above the umbilicus. Skin, subcutaneous fat, linea alba, extraperitoneal fat and peritoneum are divided in turn. The extraperitoneal fat  is abundant and vascular in the upper abdomen (especially in the obese) and small vessels must be coagulated with the dia thermy. The falciform ligament with the ligamentum teres in its free edge lies in the midline, and is best avoided by opening the peritoneum to the left or right of the midline deep to the belly of the rectus abdominis. The ligamentum teres should be double clamped, divided and ligated if it interferes with the exposure.

The lower midline incision is similar to the upper. Below the umbilicus, the linea alba is narrow and, not infrequently, the rectus sheath on one or other side is inadvertently opened.

In general, the peritoneum in the upper midline incision should be opened first at the lower end so that the exact position of the ligamentum teres and falciform ligament can be identified, allowing them to be dealt with as described above. In contrast, the peritoneum in the lower midline incision is opened first in its upper part to avoid the bladder. A catheter must be placed in lower abdominal surgery to ensure that the bladder is empty.

The upper and lower incisions can be extended the part or the whole extent of the abdominal wall. Most surgeons circumnavigate the umbilicus with the scalpel, but others take the incision directly through the umbilicus.

Paramedian Incision

The paramedian incision was originally used to access much of the lateral viscera, such as the kidneys, the spleen, and the adrenal glands (Fig 1).

The incision runs 2-5cm lateral to the midline, cutting through the skin, subcutaneous tissue, and the anterior rectus sheath. The anterior rectus sheath is separated and moved laterally, before the excision is continued through the posterior rectus sheath (if above the arcuate line) and the transversalis fascia, reaching the peritoneum and abdominal cavity.

The incision will take a long time and is often technically difficult, however it does prevent any division of the rectus muscle and provides access to lateral structures. A paramedian incision can damage the muscles’ lateral blood and nerve supply, which may result in the atrophy of the muscle medial to the incision.

Right iliac fossa muscle split incision (Mc Burney’s / Gridiron Incision & Rocky-Davis / Lanz incision)

The right iliac fossa muscle split incision is the incision of choice for appendicectomy. The external oblique aponeurosis is divided along the line of its fibres, and the internal oblique and trans- versus abdominis muscles are split along their lengths. There’s no postoperative weakening of the abdominal wall because no muscles are cut across. Wound dehiscence and incisional herniation are virtually unknown if this incision is performed correctly.

The skin incision is centred at McBurney’s point (Gridiron incision), two-thirds of the distance along a line which joins the umbilicus to the anterior superior iliac spine, and is placed at right angles to this line. This places the incision along the line of the fibres of the external oblique aponeurosis.This is a useful incision in the obese subject or if the incision must be extended, by:

• enlarging the skin incision
• extending the incision laterally by dividing the oblique muscles.

In most cases a more aesthetic skin crease incision is used (Lanz incision). However, a common mistake is to use McBurney’s point as the centre of the incision: this will place it too medially and the operator will find himself over the anterior rectus sheath. Hence, in the patient of average build, the transverse skin crease incision should start 1–2 cm medial to the anterior superior iliac spine.

After dividing skin and subcutaneous fat, the external oblique aponeurosis is divided along the line of its fibres. The fibres are retracted to expose the underlying internal oblique muscle, which is opened with artery forceps or closed scissors at right angles to the fibres or external oblique, starting at the lateral edge of the rectus sheath. The under-lying transversus abdominis muscle is closely applied to the internal oblique and will usually be found to be split open with it; the two muscles are then widely opened with the two index fingers and held apart with retractors. A fold of peritoneum is then picked up with forceps, carefully nicked open with the scalpel and the opening stretched with the two index fingers.

Kocher Incision

A Kocher incision is a subcostal incision used to gain access for the gall bladder & the biliary tree. It is usually performed on the right side (e.g. biliary surgery), but may be performed on the left (Chevron/Rooftop incision) or the two may be joined across the midline to give major access to the upper abdomen (Mercedes Benz incision).

The skin incision starts in the midline 2.5–5 cm below the costal margin. Some surgeons employ an almost transverse skin crease incision. The incision is about 12 cm long in the subject of average size and build. After dividing skin and subcutaneous fat, the anterior rectus sheath is divided along the line of the incision. The rectus muscle is divided using diathermy to control branches of the superior epigastric vessels. The lateral abdominal muscles are split in an outward direction to provide extra access. The small 8th intercostal nerve is sacrificed, but the larger 9th nerve (lying between the internal oblique and transverse muscles) should be identified and saved. The incision is deepened to open the posterior rectus sheath and underlying peritoneum.

Two modification of Kocher Incision

Chevron/Rooftop incision

• the extension of the incision on the other side of the abdomen.
• Used for splenectomy, gastrectomy, oesophadectomy, bilateral adrenalectomy etc

Mercedes Benz incision

• The Kocher & chevron incision joined together across the midline with a vertical incision & breakthrough the xiphisternum.
• Used for liver transplant & other hepatic surgeries.

Pfannenstiel incision

The Pfannenstiel incision is a useful incision for:

• elective open gynaecological surgery
• elective Caesarean section
• the retropubic approach to the prostate and the bladder neck

The incision is placed in the curving interspinous skin crease, immediately inferior to the pubic hair line in the female. At this level, the superficial fascia is in the two layers, the: more superficial fatty layer (Camper’s fascia) & deeper fibrous layer (Scarpa’s fascia).

The fatty layer contains three sets of vessels that must be divided and tied; these are, from medial to lateral.

• external pudendal
• superficial inferior epigastric
• superficial external iliac arteries, together with their veins.

The anterior rectus sheath is divided on both sides along the length of the wound. The cut edge of the sheath is lifted and dissected away from the adherent anterior aspect of the rectus muscle on each side by scissors or scalpel dissection. The rectus muscles are retracted laterally from each other to expose the underlying peritoneum and the peritoneum is then opened in the midline.

It is easy to damage the bladder in this procedure unless two vital precautions are taken:

• empty the bladder before the operation by means of a self- retaining catheter, which is left in situ
• start opening the peritoneum at the upper end of the wound.

Transverse Incision

A useful laparotomy technique for use in paediatric patients who have not yet developed deep subphrenic or pelvic recesses, and in whom the surgeon, therefore, does not need the ability to extend the incision longitudinally as afforded by the midline incision. This incision is also commonly utilised by vascular surgeons for elective and emergency repair of abdominal aortic aneurysms. 

Thoracoabdominal Incision (Iver Lewis)

The thoracoabdominal incision is a unique incision that connects the pleural cavity and the peritoneal cavity; it yields great exposure to lateral organs, retroperitoneal space, pleural space, and the distal esophagus. Right-sided incisions may yield proper exposure to the hepatic region as well as the right kidney. A left-sided incision may yield exposure for the stomach as well as the distal esophagus.

When performing this incision, the patient is placed with their abdomen tilted 45 degrees from horizontal, and the thorax twisted into the completely lateral position. This position will expose the abdomen as well as the lateral thoracic region. A vertical incision through the left or right upper quadrant is made to explore the abdominal contents first, and then the incision is extended through the eighth intercostal space from medial to lateral for pleural exposure. The incision will disrupt the rectus abdominis, the oblique muscles, if placed lateral, as well as the transversus abdominis. The thoracic end extends through the intercostals, as well as the latissimus dorsi muscle. Once the thoracic cavity is entered, the lung is deflated. The two incisions should meet at a sharp angle for cleaner closure. Blood supply to the latissimus dorsi is the thoracodorsal artery. This blood supply may be interrupted during the pleural incision laterally. The abdominal incision could lead to disruption in superior epigastric branches.

McEvedy Incision

The McEvedy is a vertical incision from the femoral canal and brought superior to above the inguinal ligament. It opens the femoral space to allow access to the femoral canal as well as the peritoneum. Femoral hernias may be reduced and repaired through this incision. If the peritoneal cavity needs to be accessed, this will provide minimal access, as the incision is not really over the peritoneal space. Due to the location on top of the femoral canal, special care needs to be taken not to injure the femoral vein, artery, or nerve.

Supra-umbilical/Infra-umbilical Incision

Supra and infra-umbilical incisions (Fig 1) are used for access into the peritoneum through the tissues surrounding the umbilicus. Due to the umbilical stalk, it is unwise to incise directly through the umbilicus so the incision must route around it. Infra-umbilical incisions may be vertical (such as when gaining access for a Hasson port) along the linea alba, which is avascular. The incision may be transverse if the surgeon is performing an open umbilical hernia repair. Supra-umbilical incisions may be used to gain access into the peritoneum or for open umbilical hernia repairs when there have been previous incisions in the infra-umbilical region. If the transverse incision is made, then it may be used in a tight “U,” or inverted “OMEGA” shape around the umbilicus to keep the future scar hidden, or it can be curvilinear to match the natural curve of the umbilical ridge. However, one must make sure not to devascularize the umbilical stalk or the thin umbilical skin. If an incision is made along the umbilical ridge, then there must be enough untouched skin on the opposing side of the incision to provide sufficient blood supply.

Pararectus

A para-rectus is an incision that is made through the semilunar line laterally to the rectus abdominis muscle (Fig 1). This incision may be used for a Spigelian hernia, or if modified, can be used for an ostomy. If the incision is made circularly and the rectus abdominis is not incised but retracted, then the incision can be carried through to the peritoneum to retrieve the intestine for ostomy formation. How inferior or superior the incision is located will affect blood supply either from the inferior epigastric, the superior epigastric or in the watershed zone between the two main arteries.

Maylard Incision (Mackenrodt)

A transverse incision 6cm above the pubic tubercle that is made through the rectus abdominis to gain access to pelvic structures (Fig 1). The incision is made through the rectus abdominis on both sides, through the linea alba, and the medial aspects of the obliques. The portions of inferior epigastric, as well as the superficial epigastric, will be damaged.Can be used for cesarean cases.

Gibson (either side but conventionally left)

Three centimeters above and parallel to the inguinal ligament is the Gibson incision (Fig 1). It is used in gynecological procedures as well as urological procedures (renal transplant)

Inguinal incision (Groin)

The inguinal incision is a transverse or oblique incision over the inguinal canal. This incision is used for open inguinal hernia repairs. The incision is made through the skin to the subcutaneous fat, through Camper and Scarpa fascia. The superficial epigastric veins are commonly encountered and ligated. This incision reaches the external oblique aponeurosis and provides access to the inguinal canal.

CHEST INCISIONS

Subclavicular Incision (Infraclavicular incision)

Made transversely through the skin and subcutaneous tissues inferior to the clavicle, giving access to the subclavian vessels.

Supraclavicular Incision

This incision is a transverse incision superior to the clavicle. It may extend along the length of the clavicle to the midline of the sternum and will provide access from another vantage point to the subclavian vessels. The advantage of this incision is that it can meet a sternotomy incision or a cervical incision to provide greater exposure to cervical anatomy or thoracic anatomy. When making this incision, care must be taken medially to avoid the internal and external jugular veins. The platysma will be severed, and the incision provides access to the anterior scalenes as well. This approach is most often utilized in trauma to gain access to the subclavian vessels.

Median Sternotomy

The sternotomy is a vertical incision over the sternum. It is used to access the mediastinum, pleural cavity, the aorta and branches to the head and upper extremities, as well as the epigastric region. It is the most commonly used open heart incision.

  Trapdoor Incision

The trapdoor incision is a combination of the collar incision, the sternotomy, as well as a laterally extended incision from the inferior aspect of the sternotomy below the pectoral muscles. This incision is used rarely to control bleeding from penetrating trauma to zone three of the neck, and on occasion is used for aortic arch aneurysms. The trapdoor incision opens a “door” to the pleural space, the mediastinum, the cervical vasculature, and the heart. The three incisions that are used still need to be conducted carefully due to the vascular supply as well as the nerves running along the anterior chest wall. The blade used needs to be handled with care because if it is too deep then the lung, aorta, or other major vascular structures may be injured, leading to hemorrhage.

Clamshell Incision

Clamshell incision is a large transverse incision that spans across the entire chest wall. It is also known as a bilateral thoracotomy and is used during massive chest trauma, lung transplant, or resection of tumors in the chest. The incision extends through the sternum, between the fourth and fifth ribs bilaterally, and extends to the mid-axillary line. Mammary vessels will be interrupted as well as intercostal muscles with associated intercostal nerves and vessels.

NECK INCISIONS

Carotid Incision

A carotid incision is used to access the carotid sheath for carotid endarterectomy. It is made along the anterior aspect of the sternocleidomastoid muscle in a vertical direction. There needs to be are to avoid hitting the external jugular vein or the internal jugular vein. The incision will need to go through the platysma.

Thyroidectomy

Thyroidectomies are performed through a transverse incision superior to the sternal notch, and it travels parallel to the clavicles, preferably in the neck crease. Care needs to be taken to not to cut the anterior veins by cutting too deep too quickly, or this will result in heavy bleeding.

Tracheostomy

Tracheostomies are performed through a vertical or horizontal incision that overlays the trachea, superior to the thyroid over the second or third tracheal rings.

Laparoscopic Incision

Initial access is usually best achieved at the umbilicus either by using a Veress needle or the cut-down method using a Hassan trochar. A Visi port is a special port that allows for laparoscope placement in the trochar itself, then after an incision is made, direct visualization with twisting of the port and steady downward pressure is applied to gain access to the intraperitoneal space. When additional trochars are placed, it is wise to avoid any vessels that are traveling through the abdominal wall that may be illuminated by the laparoscope inserted through the previously inserted larger port. If access at the umbilical site is not advisable due to multiple surgeries, the presence of scar tissue, or large wall deformities, then the next best initial access site is the left upper abdomen. Decompression of both the stomach and bladder is recommended before any initial trochar insertion.