Chapter 2

Essential Topics in General Surgery

Michael J. Moritz

Section A: Essentials of Normal Surgical Practice

I Wound Closure

Wounds, whether traumatic or surgical, must be appropriately closed, layer by layer.

A

There are three types of wound closure and healing; the choice of technique is determined by the degree of bacterial contamination in the wound (see Chapter 1, V C, D)

Primary intention. Clean and clean-contaminated wounds can be closed in this manner. All layers are closed.

This produces the most cosmetic scar.

With the skin closed, bacteria in the subcutaneous layer can result in a wound infection.

Secondary intention. Infected wounds are closed in this manner. The deep layers are closed, while the subcutaneous layer and the skin are left open.

Wound care consists of 1 to 3 dressing changes daily, including wound irrigation, packing, and sterile dressings.

The open portion of the wound granulates and slowly re-epithelializes with a broad scar.

Because the skin is not closed, a wound infection cannot occur.

Delayed primary intention. Contaminated wounds can be closed in this manner. The deep layers are closed, while the subcutaneous layer and skin are left open and packed.

At postoperative day 4 or 5, the wound is unpacked and inspected.

If the subcutaneous tissue is clean and just beginning to granulate, then the skin edges are closed, either with sutures placed and left untied at the initial procedure or with adhesive paper tapes.

If there is purulence in the subcutaneous layer, then the wound is left open to heal by secondary intention.

B The skin

The integumentary system is the largest organ in the body

Skin layers. The two principal layers, the dermis and epidermis, have specialized functions.

The epidermis is composed of stratified squamous epithelium, which covers the entire body and provides protection. Living cells migrate from the innermost level of the epidermis to the surface to form the dead, desquamating layer. The migration takes approximately 19 days.

The dermis , which serves in a nutritive capacity to the epidermis, is itself composed of two layers.

The papillary layer is composed of fine collagen fibers, ground substance, and capillaries.

The deeper reticular layer is composed of dense collagen, hair follicles, sebaceous glands, and sweat glands.

The hypodermis or subcutaneous tissue, which lies deep to the dermis, contains fat and nutrient vessels and can contain hair follicles and sweat glands.

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A cosmetically acceptable appearance is a goal of all closures.

Atraumatic handling of tissue minimizes necrosis and decreases scarring.

Eversion of the wound edges results in a level scar with time, whereas inversion of the edges may result in an uneven or concave scar.

Early removal of skin sutures or skin staples decreases the scarring.

C

Deeper fascial layers vary with location and the type of incision (i.e., transverse vs. vertical).

Fascia generally has greater strength than other layers, and the fascial closure should assume most of the tension distracting the wound, rather than the skin.

Where multiple deep layers exist, they can be closed as individual layers or in combination. For example, a transverse abdominal incision will have four deep layers: peritoneum and transversus abdominus, internal oblique, and external oblique muscles. Often, the deepest two or three layers are closed with a single suture line, and the shallowest one or two layers are closed with a second suture line.

When the integrity of the deep layers has been violated (or they are at high risk of disruption), as in the case of wound dehiscence, then all layers—deep and superficial, including the skin—can be included in a single suture line, a so-called mass closure, usually using interrupted retention sutures.

D Closure techniques

Suture lines can either be interrupted (a new knot every one or two stitches) or continuous (many stitches between knots). Continuous sutures are also called running sutures (Fig. 2-1).

Interrupted closures

The advantages. These closures have the potential for better vascular supply to the wound edges.

The disadvantages include the greater time it takes to close with this method, the inconsistency of tension on individual sutures, and the large number of knots required.

FIGURE 2-1 Suturing techniques. A: Simple interrupted suture. B: Interrupted vertical mattress suture. C: Interrupted horizontal mattress suture. D: Continuous (running) simple suture.

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Running closures

The advantages. Running closures take less time, have greater water -tightness, and the tension is equal along the entire suture line.

The disadvantages include the potential to strangulate the tissues if the suture is placed too tightly. Also, the integrity of the closure is dependent on one or two sutures and only a few knots, disruption of which will unravel the entire closure.

Sutures, whether continuous or interrupted, can be sewn in a simple or a complex fashion.

Simple sutures are also called “over and over” sutures.

Complex suture techniques include vertical and horizontal mattress sutures and their variations (Fig. 2-1).

Simple interrupted sutures are created with equal full -thickness bites of tissue.

Vertical mattress sutures are similar to simple sutures, but an additional bite close to each wound edge is used to ensure edge coaptation (far-far, reverse direction, near -near).

Horizontal mattress sutures are similar to simple sutures, but additional parallel bites are taken (far-far, move along incision, and reverse direction, far -far).

Subcuticular sutures are intradermal closures that are usually continuous horizontal mattress sutures; the suture material is usually absorbable. The advantages are the avoidance of suture marks on the skin, and there is no need to remove sutures (especially important in pediatric cases).

E Knot tying

The standard knot is a square knot (overhand throw, then underhand throw).

To create a secure knot, braided sutures (e.g., silk, polyester, polyglycolic acid) require three or four throws, whereas monofilament sutures (e.g., nylon, polypropylene, polydioxanone) require six to eight throws.

More throws are required for thicker suture sizes, running (as opposed to interrupted) closures, and more slippery suture materials (e.g., expanded dedpolytetraflouroethylene [ePTFE]).

When there is tension on the suture, a surgeon's knot can be used, which begins with a double -overhand throw to secure the first throws. Standard square knot throws follow. This knot is slightly weaker than a square knot.

A granny knot begins with overhand throw–overhand throw, creating a slip knot, which is then cinched down to the

appropriate tightness. Standard square knot throws follow. This knot is slightly weaker than a square knot.

F Suture materials

Strength of tissue. Although the gain in tensile strength varies from one type of tissue to another, as a general principle, the strength of tissue closed primarily returns toward normal, unincised tissue (100%) at the following pace:

At 20 days, 20% of normal.

At 40 days, 40% of normal.

At 90 days, 60% of normal.

At 1 year, 70% of normal.

The first factor in classifying suture material is nonabsorbable versus absorbable (Table 2-1). The second factor to include is whether the suture material is braided or monofilament.

Nonabsorbable sutures have enduring strength and last for years. They are permanent foreign bodies.

They can serve as a nidus for harboring bacteria, resulting in infection.

When the knots are prominent and just deep to the skin, they are noticeable, and patients may complain.

Examples of situations in which to use nonabsorbable sutures include:

Prosthetic heart valves

Vascular suture lines

Hernia repairs

Any difficult closure or where the patient's ability to heal at the usual pace is compromised (e.g., radiation therapy, corticosteroid therapy).

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TABLE 2-1 Types of Suture Materials

*ePTFE, expanded PolyTetraFluoroEthylene.

Absorbable suture materials degrade completely, last a variable time, and leave no permanent foreign body.

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Absorbable sutures are made of collagen or synthetic polymers and degrade by enzymatic digestion or hydrolysis. These sutures cause more tissue reaction than nonabsorbables, especially if enzymatically degraded (collagen).

Absorbable sutures are ideal for the biliary and urinary tracts, where a permanent suture can serve as a nidus for stone formation.

There may be a decreased infection risk without the permanent foreign body to harbor bacteria.

There are no permanent knots to bother patients.

If the suture loses strength before wound healing is adequate, the risk of wound disruption or incisional hernia increases.

Braided, multistrand sutures tend to be stronger, size for size, than monofilaments.

This is especially true for shear strength (as opposed to tensile strength), which is most important at the knot.

Braided sutures are softer, more flexible, and more pliant and hence are easier to handle, easier to tie, and require fewer throws to form a secure knot.

Because braided sutures have interstices in which bacteria can hide, the risk of infection may be increased.

Braided sutures are coarser, have increased drag on tissue, and can tear fragile tissue.

Monofilament sutures have much less drag when pulled through tissue, cause less tissue reaction, and have much less risk of harboring infection.

Because monofilament sutures are stiffer, they require more throws to form a secure knot. The knots can be large and bothersome to the patient.

Monofilament sutures must be handled with greater care; crushing, crimping, twisting, or kinking weakens the strand, which can lead to suture breakage.

Sutures can also be classified as natural materials or synthetic. Both require extensive processing.

Suture size uses a scale with “0” in the middle.

Smaller sizes. As the number of 0's rises, the sutures get finer, e.g., 4-0 (0000) is smaller than 3-0 (000). The smallest standard manufactured suture size is 10 -0 (pronounced ten-oh ).

Larger sizes. The sizes increase with each integer: no. 1 and no. 2. No. 2 is the largest standard manufactured suture size.

Usage of types of sutures

Braided permanent sutures are the easiest to handle but are known for their increased risk of harboring infection, and so they have fallen out of common use for fascial closures. Examples include silk, polyester, and cotton.

Braided absorbable sutures are the most used suture material. They can be used for gastrointestinal (GI) and other visceral surgery and for general closures. Examples include polyglactin-910 and polyglycolic acid.

Monofilament permanent sutures are stiff and harder to work with but are best for cardiovascular surgery (in small sizes) and fascial closures and hernias (in larger sizes). Examples include nylon, polypropylene, and stainless steel.

Monofilament absorbable synthetic sutures are the latest suture type to be developed. As both gut and chromic gut degrade quickly, the synthetic sutures have almost replaced the gut materials. They are better than braided absorbables for fascia because they last longer. They are also widely used for biliary and urinary tract surgery. Examples include polydioxanone and polyglyconate.

ePTFE sutures are a permanent porous monofilament with properties of both braided (interstices that can harbor bacteria, easy to handle, soft inconspicuous knots) and monofilament (slippery, requires six to eight throws to secure a knot) sutures.

Stapling devices fire multiple rows of small titanium staples for GI, vascular, and pulmonary applications. The staples act similarly to permanent monofilament sutures in that they are nonreactive, do not harbor

bacteria, and are permanent. Titanium has replaced steel for permanent implantables because of its compatibility with magnetic resonance imaging (MRI).

II Surgical Tubes

A Drainage tubes

Various types of tubes are used to drain either normal body fluid that cannot be handled by the body or abnormal material, such as pus. A tube can be mandatory, such as a chest tube for a hemothorax, or optional.

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Types of drains

Closed drains are tubes connecting a body cavity to a sealed reservoir.

Gravity drainage allows fluid to drain through the tube into a reservoir at a lower level (e.g., Foley bladder catheter).

Underwater -seal drainage systems prevent air and fluid from re-entering the body. The end of the drainage tube is under water in a sealed drainage bottle at floor level. The water prevents air from reentering the tube and prevents fluid from siphoning back (e.g., chest tube).

Suction drainage applies suction to a drainage tube and can drain large volumes of fluid, such as fluids that can collect in the GI tract. It also promotes closure of “dead space,” allowing a better approximation of tissue surfaces (e.g., Jackson -Pratt drain).

Sump drains are double -lumen catheters that allow air or irrigation fluid to enter through one lumen while suction is applied to the other lumen. Sump drains are used to evacuate particulate matter, such as debris from an abscess, or as continuous irrigation catheters (e.g., nasogastric [NG] tube).

Open drains are not sealed at either end. They allow bacteria and other materials access to the drained area. Open drains are still used for some contaminated cases (e.g., Penrose drain).

Examples of situations requiring drainage

Chest tube drainage of the pleural space is usually indicated to evacuate air, i.e., pneumothorax (simple, tension), and blood, i.e., hemothorax.

A GI tract that is nonfunctional for a prolonged period (more than 1 or 2 days) or obstructed requires NG drainage, usually with a sump tube.

The decompression lessens abdominal distention, intestinal dilatation, nausea, and vomiting.

Drainage also allows one to determine the amount and type of luminal fluid loss so that appropriate replacement can be made.

Areas where bodily fluids (e.g., bile, urine, pancreatic fluid) can collect internally require drainage.

Procedures such as mastectomies or skin flaps (see Chapter 1, V D 5) where large raw surfaces are to be kept opposed require suction drainage.

Deep abscesses not amenable to simple incision require drainage (e.g., deep cavities such as subphrenic or periappendiceal abscesses). Drains cannot be used to control a generalized infection, such as cellulitis or peritonitis (see VI B 2).

Caveats and complications

The presence of a drain is no guarantee that a fluid collection will not form. The foreign body reaction can isolate a drain from adjacent tissues, preventing fluid from accessing the drain's lumen.

A drain is not a substitute for hemostasis. If hemostasis is not adequate, a hematoma will likely develop despite drainage.

Drains can become colonized by microorganisms from exogenous sources. Drains, particularly open drains, increase the risk of infection.

Rigid drains may erode through the wall of a blood vessel or a hollow intestinal structure. This complication can be minimized by using soft drains and removing drains early.

Excessive suction on a tube can cause necrosis of nearby structures. Intermittent or low -level suction or use of a sump tube is safer.

A drain in direct contact with a fistula may perpetuate the fistula and delay its healing. The drain must then be withdrawn from the fistula if healing is to occur (see VII E 2).

Drains can retract into the body. They must always be firmly attached to the skin and should be marked with a radiopaque marker. A safety pin can be used to keep small drains outside the body.

The free peritoneal space cannot be drained because tubes are quickly “walled off.” Therefore, diffuse peritonitis cannot be drained. Localized collections can be drained.

Removal. Drains should be removed when they have fulfilled their purpose.

When the main risk of leakage has passed , the drain is removed.

After a liver resection, if a leak from a bile duct is present, it should be evident in 1 or 2 days. Therefore, drains are normally removed by the third day.

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After urinary bladder procedures, a urine leak would not be noticeable until the bladder catheter is removed. Therefore, drains are removed a day after the catheter is removed.

When a drain is used for postoperative fluid collections (i.e., blood or lymph), it is removed when no substantial drainage occurs.

When the drain is used in a reconstructive procedure, it is removed once the repair is safe.

After common duct exploration, a T tube is used to drain the bile duct until spasm of the sphincter of Oddi has resolved. The T tube is removed after a cholangiogram documents free flow of bile into the duodenum.

After gastrectomy and Billroth II reconstruction, a potential complication is disruption of the duodenal stump.

A tube may be placed within the duodenal lumen (tube duodenostomy) to prevent overdistention of the proximally closed duodenum and prevent disruption.

Once the patient has recovered from the surgical procedure and if no signs of duodenal leakage

have developed, the tube can be removed 2–4 weeks after surgery.

B Gastrointestinal tubes

Gastrostomy tubes are tubes inserted between the stomach and the skin and are used for feeding purposes or for prolonged gastric decompression.

Once the tube is no longer needed, it is removed. The tract formed between the skin and stomach will close in

A port is equivalent to a central venous catheter or PICC, except there is no external extension, and a port is intended for longer -term use. The catheter is attached to a device with a septum (the port) through which to access the lumen. The port is buried subcutaneously. A port is usually used less often than daily, e.g., for periodic chemotherapy.

A cuffed central venous catheter (Hickman -type catheter) maintains access to the veins for prolonged time periods.

The catheter has a Dacron felt cuff glued to the catheter. The cuff provokes ingrowth of granulation tissue, which functions to secure the catheter's position and as a mechanical barrier to organisms entering via the skin exit site.

They can function for years. Both single - and double -lumen styles are available; they are inserted percutaneously.

Typical uses include:

Chemotherapy and phlebotomy in patients with malignant diseases.

Hemodialysis in patients with problems with standard hemoaccess.

Long-term hyperalimentation in patients with nutritional problems.

Tenckhoff peritoneal dialysis catheters are inserted into the peritoneal cavity either for long-term dialysis therapy or for management of ascites in patients with malignant disease.

They may be inserted either percutaneously or surgically and can function for years if properly maintained with sterile technique.

Two Dacron cuffs are glued to the catheter: one adjacent to the peritoneum and one adjacent to the skin exit site. The cuffs function as barriers against infection (from the skin side) and leakage (from the peritoneal side).

III Hernias

Hernias are the abnormal protrusion of intra -abdominal contents through a defect in the abdominal wall.

A Overview

Frequency of occurrence. In both men and women, hernias occur most commonly in the inguinal region (75%–80% of all hernias). Incisional (ventral) hernias occur next in frequency (8%–10%), followed by umbilical hernias (3%– 8%).

Etiology. Hernias occur as a result of various factors.

Congenital defects include indirect inguinal hernia.

Loss of tissue strength and elasticity from aging or repetitive stress may result in herniation, as in hiatal hernia.

Trauma , especially operative trauma in which normal tissue strength is altered surgically, can lead to the development of hernia. A wound infection greatly increases the risk of late incisional hernia.

Increased intra -abdominal pressure as a result of

Heavy lifting

Coughing, asthma, and chronic obstructive pulmonary disease (COPD)

Bladder outlet obstruction (e.g., benign prostatic hypertrophy)

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Prior pregnancy

Ascites and abdominal distention

Obesity

Descriptive terms. Hernias may be described according to physical or operative findings.

Reducible. The hernia contents can be pushed back into the abdomen.

Incarcerated. The hernia contents cannot be pushed back.

Obstructing. The hernia contains a loop of bowel that is kinked and obstructs the GI tract.

Strangulated. The tissue contained in the hernia is ischemic and will necrose due to compromise of its blood supply.

Sliding. The wall of the hernia sac, rather than being formed completely by peritoneum, is in part formed by a retroperitoneal structure, such as the colon or the bladder.

Richter's hernia. Only one side of the bowel wall is trapped in the hernia (typically, the antimesenteric side) rather than the entire loop of bowel. This is especially dangerous because the incarcerated portion of bowel can necrose and perforate in the absence of obstructive symptoms.

Complications. Hernias should be repaired electively to prevent the development of major complications.

Intestinal obstruction.

Intestinal strangulation with bowel perforation.

B Inguinal hernias

Anatomy of the inguinal region (Figs. 2-2 and 2-3)

The internal inguinal ring is an opening in the transversalis fascia lateral to the inferior epigastric vessels.

The external inguinal ring is an opening in the external oblique aponeurosis.

The inguinal canal is the communication between the internal and external rings.

The anterior wall of the canal is formed by the external oblique aponeurosis.

The inferior wall of the canal is formed by the inguinal ligament (Poupart's ligament ) and its reflection.

The roof of the inguinal canal (superior ) is made up of fibers of the internal oblique and transversus abdominis muscles, forming a structure termed the conjoint tendon.

FIGURE 2-2 Anatomy of the inguinal region.

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FIGURE 2-3 Sites of direct, indirect, and femoral hernias and their relationship to anatomic structures.

The posterior wall or floor is formed by the transversalis fascia.

Within the posterior wall of the inguinal canal is Hesselbach's triangle.

The triangle is formed laterally by the inferior epigastric artery, inferiorly by the inguinal ligament, and superomedially by the lateral border of the rectus sheath.

In women , the round ligament traverses the inguinal canal.

In men, the spermatic cord structures pass into the internal ring, traverse the inguinal canal, and pass through the external ring into the scrotum. Structures within the spermatic cord include:

Arteries: testicular and cremasteric

Veins: pampiniform plexus

Vas deferens

Processus vaginalis: an evagination of peritoneum that accompanies the descent of the testicle and gubernaculum through the abdominal wall. Normally obliterated, it remains patent in an indirect hernia and forms the hernia sac.

Nerves: the ilioinguinal and genital branch of the genitofemoral nerves are within the inguinal canal but are external to the cremasteric fascia, which invests the spermatic cord.

Types of hernias

Indirect inguinal hernias

An indirect inguinal hernia passes from the peritoneal cavity through the internal inguinal ring (i.e., lateral to the epigastric vessels) and down the inguinal canal (Fig. 2-3). It may, on occasion, extend into the scrotum.

When the processus vaginalis is incompletely obliterated, a spermatic cord hydrocele may result, with or without an indirect inguinal hernia.

Incidence

Indirect inguinal hernias are the most common type of hernia in both men and women. They are 5 to 10 times more common in men than in women. Approximately 5% of men develop an inguinal hernia during their lifetime and require an operation.

Indirect inguinal hernias are five times more common than direct hernias.

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Indirect hernias may occur from infancy to old age but generally occur by the fifth decade of life.

A pediatric inguinal hernia (see Chapter 29, II) is almost always indirect and has a high risk of incarceration. It is more common on the right (75%) and is often bilateral.

Potential indirect hernias are associated with an undescended testis, a testis in the inguinal canal, and a hydrocele.

Bilateral patent processus vaginalis occurs in up to 10% of patients with an indirect inguinal hernia.

Direct inguinal hernias. The inferior epigastric vessels are the anatomic landmarks that distinguish indirect from direct inguinal hernias, which occur medial to the epigastric vessels.

A direct inguinal hernia occurs through the floor of the inguinal canal, i.e., through Hesselbach's

triangle (Fig. 2-2), because of an acquired weakness in the tissue.

The hernia is a direct protrusion of abdominal structures into the floor of the canal posterior to the spermatic cord. It is not contained in the cord as is an indirect hernia, and it does not pass into the scrotum. The sac is a broadly based defect. It is much less often associated with strangulation than an indirect inguinal hernia.

Direct inguinal hernia increases in occurrence with age and is related to physical activity.

A recurrent inguinal hernia usually recurs as a direct hernia. Most commonly, the defect occurs in the most medial aspect of the repair of the floor of the inguinal canal.

Pantaloon hernias are combinations of direct and indirect hernias in which the hernia sac passes both medially and laterally to the epigastric vessels.

Femoral hernias

A femoral hernia occurs along the femoral sheath in the femoral canal (Fig. 2-3).

The hernia contents protrude posterior to the inguinal ligament, anterior to the pubic ramus periosteum (i.e., Cooper's ligament ), and medial to the femoral vein.

The hernia traverses the femoral canal and can present as a mass at the level of the foramen ovale. It may also turn cephalad once it has exited the foramen ovale and can cross anteriorly to the inguinal ligament.

The sac has a narrow neck, and 30%–40% of femoral hernias become incarcerated or strangulated.

Femoral hernias are more common in women than in men.

Femoral hernias are associated with being female, prior pregnancy, and prior inguinal hernia repair.

Diagnosis of an inguinal hernia is based on history and physical examination.

The history may include the appearance of a lump in the groin. The mass may be intermittently present and may be painful. Its appearance is often associated with activity.

Physical examination should be performed with the patient in both the supine and standing positions.

A mass may be visible, and its size and visibility may depend on the patient's position.

The mass may be tender or may be reducible with gentle pressure.

The examining finger should be placed along the spermatic cord at the scrotum and passed into the external ring along the canal.

The mass may become palpable as an impulse felt by the examining finger upon a sudden increase in intra -abdominal pressure, as occurs with a cough.

A direct hernia causes a forward bulge low in the canal.

An indirect hernia touches the tip of the examining finger.

The differential diagnosis of an inguinal mass includes a hydrocele, a varix (especially if thrombosed), an inflamed or enlarged lymph node, a lipoma of the spermatic cord, an undescended testicle, or an abscess or tumor.

Repair of inguinal hernias. Surgery is the only curative procedure for inguinal hernias; there are no lesser therapies that have proved effective. A recent study has reported that the risk of incarceration is low in minimally symptomatic hernias and that observing them is a safe alternative (JAMA. 2006 Jan 18;295(3):285–292).

Repair of indirect inguinal hernia involves

Return of the hernia contents into the peritoneal cavity;

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Division and/or ligation of the base of the hernia sac at the level of the peritoneal cavity—the sac is always anteromedial to the cord at the level of the internal ring;

In adults , tightening of the internal ring and repair of the abdominal wall defect inguinal canal floor to prevent recurrence.

Repair of direct inguinal hernia is based on reinforcement of the inguinal canal floor after invaginating the hernia sac.

Repair of femoral hernia involves approaching the femoral sheath through the floor of the inguinal canal. The space is closed by apposing the posterior reflection of the inguinal ligament to Cooper's ligament (Cooper's ligament repair) or by plugging the space with polypropylene mesh.

Repair of the floor of the inguinal canal can be done with many techniques. Two classic techniques used less commonly now are described first, then two newer techniques are described.

Bassini repair

The transversalis fascia and conjoint tendon above are sutured to the reflection of the inguinal ligament (i.e., the shelving edge of Poupart's ligament) below.

In men, the spermatic cord is returned to its normal anatomic location between the reinforced inguinal canal floor and the external oblique aponeurosis.

In women, the round ligament may be ligated and the internal ring closed (true for all inguinal hernia repairs in women).

Cooper's ligament repair (McVay's method)

This method is similar to the Bassini repair except that the transversalis fascia and conjoint tendon are sutured to Cooper's ligament, which is the periosteum of the pubic ramus.

Because Cooper's ligament is more posterior than the inguinal ligament and subjects the repair to increased tension, a “relaxing” incision is often made in the anterior rectus sheath adjacent to the external oblique aponeurosis. This counterincision allows the conjoint tendon to be sutured to Cooper's ligament with less tension.

Tension is the problem with this technique, causing both postoperative pain and early and late recurrences.

Shouldice repair uses the transversalis fascia, which is divided longitudinally and imbricated upon itself in two layers. The internal oblique muscle and conjoint tendon are then sutured to the reflection of the inguinal ligament in two layers (total four suture lines).

Prosthetic mesh repairs (Lichtenstein repairs) are supplanting older techniques. These involve repairing the inguinal floor by using mesh to close the space, suturing it (as in a Bassini repair) to the transversalis fascia and conjoint tendon above and to the reflection of the inguinal ligament (i.e., the shelving edge of Poupart's ligament) below.

Open and laparoscopic techniques (Chapter 30) are used to place polypropylene mesh to reinforce the weakened transversalis fascia. Open techniques also place mesh into the defect deep to the transversalis fascia.

For indirect hernia repairs, a cone -shaped polypropylene mesh is placed adjacent to (anteromedial to) the spermatic cord.

For direct hernia repairs, the cone -shaped mesh is used to “plug” the transversalis fascia defect.

Recurrence rates after surgical repair vary depending on the type of hernia, but generally, inguinal hernias recur in under 10% of cases. This figure is usually higher for hernias at other sites.

Special situations

When strangulation or necrosis of the incarcerated bowel is suspected but the bowel returns to the peritoneal cavity spontaneously before visual examination by the surgeon, the abdomen should be opened and explored so that any necrotic bowel can be resected.

Recurrent hernias or hernias with large defects may require the insertion of prosthetic material such as polypropylene mesh to repair the abdominal wall defect adequately.

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Simple high ligation of the hernia sac is used for hernias in the pediatric age group. No floor repair is needed.

A truss is a device that exerts external compression over the hernia defect, keeping the space compressed. It is used only when surgery cannot be safely performed or when the patient refuses surgery.

C Other types of abdominal wall hernias

Umbilical hernias occur through the defect where the umbilical structures passed through the abdominal wall.

Umbilical hernias occur 10 times more often in women than in men.

The defect is common in children but usually closes by age 2 years, and fewer than 5% of umbilical hernias persist into later childhood and adult life.

In adults, umbilical hernias are often associated with increased intra -abdominal pressure, as with ascites or pregnancy.

Repair of an umbilical hernia consists of a simple transverse repair of the fascial defect.

Epigastric hernias, also called epiploceles , result from a defect in the linea alba above the umbilicus.

They occur more commonly in men (in a 3:1 ratio).

Some 20% of epigastric hernias are multiple at the time of repair.

Repair (simple suturing) is associated with a recurrence rate as high as 10%.

Ventral hernias occur in the abdominal wall in areas other than the inguinal region.

An incisional hernia , the most common type of ventral hernia, results from poor wound healing in a previous surgical incision and occurs in 5%–10% of abdominal incisions.

Common causes include midline incision, wound infection or hematoma, advanced age, obesity, general debilitation or malnutrition, surgical technique, or a postoperative increase in abdominal pressure, as occurs with paralytic ileus, ascites, or pulmonary complications after surgery.

Incisional hernias are repaired after the patient has recovered from the prior surgery trauma.

Repair requires definition of the adequate fascial edges surrounding the defect, closure with nonabsorbable sutures, and use of prosthetic mesh (polypropylene or ePTFE) when the defect is too large to be closed primarily.

Spigelian hernias protrude through the abdominal wall along the semilunar line (the lateral edge of the rectus muscle) at the semicircular line of Douglas (below the umbilicus where the transversus abdominis and internal oblique aponeuroses change to pass anteriorly to the rectus muscle).

Obturator hernias occur in the pelvis through the obturator foramen. The hernia can cause pain along the obturator nerve (mid -anterior thigh), referred to as Howship -Romberg sign.

Lumbar hernias occur on the flank and are seen in the superior (Grynfeltt's) and inferior (Petit's) triangles.

Perineal hernias occur in the pelvic floor usually after surgical procedures such as an abdominoperineal resection.

Peristomal hernias develop adjacent to an intestinal ostomy.

IV Surgical Oncology

A Overview

Cancer is a group of diseases caused by unregulated growth and spread of neoplastic cells. Neoplasias may be either benign (noninvasive growth, no metastases) or malignant (invasive growth, metastases).

Types

Carcinomas are malignancies that arise from epithelium.

Adenocarcinomas are malignancies that arise from epithelium and have a glandular component.

Sarcomas are malignancies that arise from mesodermal tissues.

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Neoplastic transformation. Neoplastic cells have “escaped” from the normal homeostatic inhibition (or regulation) of cell proliferation. Causes of neoplastic transformation are listed next with illustrative examples of human tumors. Because no single etiology exists for most human cancers, remember that multiple factors lead to neoplastic transformation.

Chemical carcinogens. Soot is associated with cancer of the scrotum of chimney sweeps (described by Pott in 1775); asbestos is associated with mesothelioma of the pleura; and smoking tobacco is associated with squamous cell carcinoma of the lung.

Physical carcinogens. Ultraviolet light is associated with basal cell and squamous cell carcinomas of the skin; ionizing radiation is associated with bone cancer in radium-dial workers, lung cancer in uranium miners, and leukemia in atomic bomb survivors (Hiroshima); and papillary thyroid cancer appears in individuals treated with neck irradiation.

Hereditary factors. A few cancers have direct genetic links, such as retinoblastoma, familial adenomatous polyposis, and multiple endocrine neoplasia syndromes (e.g., pheochromocytoma, medullary carcinoma of the thyroid, and other endocrine tumors) (Chapter 17).

Geographic factors are unexplained epidemiologic phenomena whereby a particular cancer is very common in

certain locations (e.g., gastric cancer is common in Japan and esophageal cancer in southeastern China).

Oncogenic viruses. Epstein -Barr virus is linked to Burkitt's lymphoma and nasopharyngeal carcinoma; human papilloma virus is linked to cervical and anogenital carcinomas; human T -cell leukemia virus type 1 (HTLV-1) is linked to adult T -cell leukemia; and hepatitis B and C are linked to hepatocellular carcinoma.

B Epidemiology

Cancer is the second leading cause of death in the United States (20% of all deaths); approximately 1 million new cases are diagnosed annually. One in four U.S. residents will develop cancer during his or her lifetime, with an overall 5-year survival rate of 40%.

Mortality

Overall, the highest number of deaths is caused by lung cancer (incidence rising), followed by colon and rectal cancer and breast cancer (incidence stable), and pancreatic cancer (incidence rising). Lung cancer is now the most common cause of cancer death for both sexes (having exceeded breast cancer for women).

A decreasing number of deaths are found from gastric cancer and uterine/cervical cancer. For gastric cancer, the incidence is falling for unknown reasons. For uterine/cervical cancer, early diagnosis (Pap smear) and improved treatments are presumably responsible.

Incidence. Overall, the order is the same as for mortality. However, for women, the most common cancer is breast

cancer.

C Molecular physiology of neoplastic cells

Neoplastic cells proliferate more rapidly than normal cells and fail to acknowledge signals to stop dividing.

Cancer is caused by a cascade of inherited and acquired mutations in those genes, which result in unsuppressed cellular proliferation.

Mutations in DNA produce altered or lost genes: point mutations (altered single base pair), deletions (loss of a DNA segment), and translocations (rearrangements).

Recessive mutations must cause loss of both copies of a growth -regulating molecule to contribute to malignant transformation.

There are at least three types of cancer-causing genes.

Oncogenes result from mutations of the normal host proto -oncogenes.

Proto -oncogenes are expressed during cellular proliferation, e.g., during embryonic development or during injury/healing responses.

Examples of oncogenes:

The HER -2/ neu gene is a membrane receptor mimic, and it encodes a protein similar to the epidermal growth factor receptor. This gene is amplified (overproduced) in 30% of breast and ovarian carcinomas and independently adversely effects prognosis.

The ras oncogene encodes a signal transduction protein and is found in 20% of solid tumors and in 50% of colon carcinomas.

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C-myc is a nuclear transcription factor that binds to enhancer and promoter regions of target genes. C-myc expression is increased in many solid tumors. In Burkitt's lymphoma, c-myc is uniformly translocated adjacent to the immunoglobulin (Ig)G or IgM light chain genes.

Tumor suppressor genes function to suppress or regulate cellular proliferation.

Loss of function results from mutation or deletion in both genes.

p53 is a tumor suppressor oncogene. Normally, p53 suppresses DNA replication sites.

Loss of p53 is the single most common genetic change found in malignancy (75% of colon carcinomas, 90% of hepatocellular carcinomas caused by aflatoxin).

Human papilloma virus gene product E6 binds and inhibits p53.

C

DNA repair genes encode for proteins that correct most of the errors that creep into replicated DNA. Diminished or lost function of these genes increases the net mutation rate in other genes.

D Multistep carcinogenesis

Malignancy is the result of the accumulation of critical mutations that produce a cancerous cell.

As a corollary, a single specific oncogene or lost suppressor gene may be necessary but not sufficient by itself to produce the malignant phenotype.

An important point is the diverse functions of the lost or mutated molecules. The multiplicity of genes and their products and the multitude of possible mutations leads to enormous diversity on every level for human cancers.

Hereditary factors are well illustrated by the BRCA -1 and BRCA -2 genes.

BRCA -1 and BRCA -2 are genes, certain mutations of which increase a woman's risks of breast (BRCA -1 only) and ovarian cancers. These mutations are usually inherited and are highly penetrant autosomal dominant traits.

The BRCA -1 gene is a tumor suppressor gene. Mutations are present in 10% of young women (younger than 35 years old) with breast cancer but in 20% of young Jewish women with breast cancer.

For BRCA -1 and BRCA -2, the prevalence of these mutations is 0.0014. The cumulative lifetime risk of breast cancer for carriers is 73.5%, in contrast to a risk of 6.8% for noncarriers.

For ovarian cancer, the equivalent lifetime risks are 28% for carriers and 2% for noncarriers.

In the United States, individuals with BRCA -1 mutations account for 3% of breast cancers and 4.4% of ovarian cancers.

The steps in colon carcinogenesis are relatively well understood.

APC (adenomatous polyposis coli) gene mutations occur early and may be the first event in tumorogenesis of sporadic cases. APC mutations are typically found in benign calonic adenomatous polyposis.

When two copies of this recessive gene are inherited, the individual has Familial Adenomatous Polyposis and develops multitudinous colonic polyposis with early cancers.

The DCC (deleted in colorectal carcinoma) gene is typically lost late in adenomatous polyposis. Loss of the DCC gene also plays a role much later, after tumorigenesis, in propensity of a cancer to metastasize.

K -ras, an oncogene, typically mutates in adenomes, perhaps enabling small adenomatous polyposis to enlarge.

p53 is a tumor suppressor gene, and loss of the second normal allele typically occurs at the initiation of malignancy.

For HNPCC (hereditary nonpolyposis colon cancer), a different etiology of carcinogenesis has been described. These patients are hypermutable because of defects in the DNA repair genes. However, the cascade of mutations seen in sporadic colon cancers (APC, DCC, K -ras, p53) also occurs in HNPCC.

Cancerous cells (i.e., growth unregulated cells) are not necessarily capable of metastasis. Further changes are required to produce the metastatic phenotype. Some of these changes may include the following:

Altered or increased expression of cell adhesion molecules or their receptors, which allows circulating blood - or lymph -borne cancer cells to adhere to endothelial cells.

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Ability to produce extracellular matrix molecules for its own milieu or enzymes to degrade the existing matrix, e.g., type IV collagenase to degrade endothelial basement membrane collagen and to gain access to new tissues.

Ability to produce cytoskeletal proteins for increased cell motility.

Ability to produce angiogenic factors for neovascularization of the new “colony.”

E Diagnostics

A single malignant cell that undergoes 30 doublings results in 1 billion cells, which creates a 1-cm diameter tumor.

With tumor doubling times of clinical cancers ranging from 20–120 days, one can extrapolate that most human tumors have been present for 1–10 years to reach clinical detection.

Flow cytometry is a test done on tumor cells to detect the relative amount of DNA and the growth rate.

Ploidy describes the amount of DNA.

Diploid signifies a normal amount of DNA (i.e., two copies of each chromosome).

Aneuploid signifies abnormal DNA content.

Polyploid signifies increased DNA content at integer multiples of normal.

S -phase measures the proportion of cells in the S -phase of the cell cycle. When elevated, this indicates more rapid tumor growth and presumably a more aggressive tumor.

Tumor markers are tests developed to detect tumor or tumor-specific products.

Classification includes tumor-specific antigens, tumor-specific enzymes, and tumor-specific hormones.

Screening. A marker used for screening should possess a high sensitivity for the detection of early, curable lesions in asymptomatic patients. Prostate-specific antigen (PSA) is an example.

Prognosis and detection of residual disease. Carcinoembryonic antigen (CEA) is used as a measure of colorectal malignancy. A rising level of CEA indicates recurrence as well as prognosis (see Chapter 13, IV B 9 c).

Molecular diagnostics increases the sensitivity of biopsy material.

For more accurate pathology of lymph nodes in breast cancer, immunohistochemistry is used to look for cytokeratin (an epithelial cell marker) in lymph nodes. Approximately 10%–30% of nodes considered negative with standard pathology will be found positive by the above techniques.

Quantitative immunohistochemistry for oncogene c-erbB -2 on frozen sections of breast cancer primary tumors correlates increased expression of c-erbB -2 with poorer survival.

To increase the sensitivity of pancreatic aspiration cytology biopsies, polymerase chain reaction (PCR)

amplification for the K -ras oncogene has a 96% sensitivity for pancreatic cancer cells.

F Clinical manifestations of cancer

Seven classic symptoms of cancer spell out the mnemonic “CAUTION:”

Change in bowel or bladder habits

A sore that does not heal

Unusual bleeding or discharge

T hickening or lump in the breast or elsewhere

I ndigestion or difficulty swallowing

O bvious change in a wart or mole

Nagging cough or hoarseness.

Other manifestations

Growth, causing a mass, obstruction, or neurologic deficit

Growth into neighboring tissues causing pain, paralysis, fixation, or immobility of a palpable mass

Tumor necrosis causing bleeding or fever

Systemic manifestations such as thrombophlebitis, endocrine symptoms due to hormones secreted by the tumor, and cachexia

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Extreme weight loss over a short period of time

Metastatic spread as the first symptom such as enlarged lymph nodes, neurologic symptoms, or pathologic bone fractures.

Screening tests for cancer detection. Asymptomatic cancers detected by screening generally have a better prognosis than symptomatic cancers. Common screening tests and the current American Cancer Society's recommendations for their use include:

Mammography (annually after age 35–40)

Stool for occult blood and digital rectal examination (annually after age 50)

Pap smear of the cervix (every 3 years after two negative tests 1 year apart)

G Staging of cancer

The standard staging of most cancers is based on the tumor, nodes, and metastasis (TNM) system. Various TNM classes are then grouped into stages. The staging of gastric cancer will be used to exemplify this system (Table 2-2).

T describes the primary tumor.

N describes the involvement of lymph nodes with metastatic spread.

M describes distant metastases.

Stage grouping. Staging is necessary to choose the appropriate therapy and to assess the prognosis. It also allows investigators to report their results in a standardized way so that conclusions regarding treatments and their outcomes are interpretable.

H Diagnostic procedures

Biopsy. It is mandatory that tissue be obtained to prove microscopically that a malignancy is present. Therefore, a biopsy is always obtained in diagnosing and treating cancer. There are several types of biopsy.

Aspiration biopsy or aspiration cytology biopsy. A narrow needle (e.g., 22 -gauge needle) is inserted into the lesion, and cells are aspirated into the needle and deposited on slides. The specimen is similar to that obtained by a Pap smear and is read by a cytopathologist.

TABLE 2-2 Tumor, Nodes, and Metastasis (TNM) Classification System and Stage Grouping for Gastric Adenocarcinoma

Tumor (T)

Stage grouping

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Needle biopsy. A large needle (e.g., 18 -gauge) is inserted into the lesion and a core of tissue is removed for histology. Because a needle biopsy removes more tissue than does aspiration, complications (e.g., bleeding) are more common, but the specimen is larger and the diagnosis obtained is more precise.

Incisional biopsy removes a superficial or accessible portion of the lesion for diagnosis.

Excisional biopsy completely removes a discrete tumor without a wide margin of normal tissue and is not curative for malignancy. It is used when local removal will not interfere with the therapy to be used for definitive local control.

Staging laparotomy for Hodgkin's disease establishes the correct stage.

Imaging studies , such as computed tomography (CT) scan, ultrasound, and MRI are useful for assessing the extent of spread when the study is positive. A negative imaging study does not exclude the possibility of microscopic disease spread.

Positron emission tomography (PET) scanning is an imaging modality that measures the radiation emitted by radioactive tracer molecules as they are taken up by specific cells.

The data are translated into an image by CT reconstruction.

Cancer cells exhibit accelerated glucose membrane transport. Administered radio-labeled 2-fluoro -2- deoxy -D-glucose (FDG) is metabolized intracellularly and remains trapped in the cell for essentially all human cancers.

PET -FDG scanning has been demonstrated to be superior to CT scanning in detecting colorectal cancer both for preoperative staging and post-treatment assessment of recurrence, metastases, etc.

Laparoscopy for staging has become standard for upper abdominal tumors (gastric, pancreatic, hepatic) to exclude intra -abdominal spread. This decreases the number of laparotomies at which unresectable (i.e., nonsurgical) disease is found.

I Multimodality cancer therapy

Most cancer patients are treated surgically, with radiation, chemotherapy, and immunotherapy playing increasingly important roles. Choice of therapy is based on disease, stage, histologic grade, patient age, other concomitant diseases, and the intent of therapy (i.e., cure vs. palliation).

Surgery and radiation therapy are both used for the treatment of the primary tumor and the regional lymph nodes. Neither has any effect on areas of distant spread.

Chemotherapy and immunotherapy are systemic therapies with the potential to affect distant areas of spread.

Adjuvant therapy is systemic therapy used for patients with local control (e.g., resection) who are at high risk of microscopic disease existing in lymph nodes or distant organs. A high proportion of these patients would develop recurrence at these sites, and adjuvant therapy attempts to destroy these distant, microscopic foci of cancer.

Multimodality therapy uses the advantages of each therapy to counteract the shortcomings of others. Examples follow:

Curable breast cancer. Surgery (mastectomy) or surgery (lumpectomy) plus radiation are used for local control. Surgery is used for staging of axillary lymph nodes, and postoperative chemotherapy is used for patients with positive malignancy in the nodes to decrease the chance of metastatic disease.

Pancoast tumor of the lung. Preoperative radiation is used for regional spread into the brachial plexus to decrease the tumor's size and to render the tumor surgically resectable.

Extremity sarcoma. Incisional biopsy is used for diagnosis; preoperative radiation therapy is used to decrease tumor size; radical local resection is used for initial local control; postoperative adjuvant radiation is used for further regional control; and chemotherapy is used for systemic control.

J Cancer surgery

The principles of cancer surgery are based on removing a tumor for cure. To prevent implantation of tumor cells at surgery, dissection is done through uninvolved tissue, staying away from the tumor. To prevent vascular dissemination, tumors are minimally manipulated, and the vascular pedicle is ligated early. To prevent lymphatic spread , the measures described previously are performed, plus the lymph node draining area is removed in continuity with the tumor.

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Curative resection. The several types of curative resection vary with the tumor's size, biologic behavior, and location.

Wide local resection is adequate for low -grade neoplasms that do not either metastasize to regional lymph nodes or deeply invade surrounding tissue. Examples include basal cell carcinoma of the skin or mixed tumor of the parotid gland.

Radical local resection is used for neoplasms that deeply invade surrounding tissue, e.g., extremity sarcoma where the resection includes the entire biopsy incision and the entire muscle compartment where the tumor lies.

Radical resection with en bloc excision of lymphatic drainage is used for tumors that usually first metastasize to regional lymph nodes (e.g., colon cancer where the segment of colon plus regional mesentery and lymphatics are removed as one specimen).

Super radical resections remove large portions of the body and are reserved for locally extensive disease with low likelihood of metastatic spread. Examples include pelvic exenteration removal of rectum, bladder, uterus [in women], and all pelvic lymphatics and soft tissues) for locally advanced cancers of the rectum, cervix, uterus, or bladder.

Staging procedures are used to establish the extent of disease to guide treatment.

Lymph node dissections for breast cancer and malignant melanoma are important for assessing prognosis and determining treatment. There is significant morbidity associated with lymph node dissection.

Sentinel lymph node excision is a less invasive, potentially equally accurate staging technique.

The tumor or just adjacent to the biopsy site is injected with a tracer , which is followed to the first lymph node draining the area.

The tracer can be a visible dye (isosulfan blue) or a radioactive tracer (technetium-99m[ 99 Tc]-labeled sulfur colloid) visualized with a hand-held gamma probe.

The sentinel node can be identified in about 95% of cases; however, excisional biopsies distort lymphatic drainage and lead to lack of success in identifying the node and also compromise the technique's accuracy.

The false -negative rate for sentinel node biopsy (negative sentinel node but other nodes in the same area positive) is less than 5%.

The diagnostic accuracy depends on precise pathology, often utilizing immunohistochemistry (see IV E 5).

Other surgical resections

Resection of recurrent cancer is occasionally feasible with localized recurrences. Examples include local (anastomotic) recurrence of GI cancer and local recurrence of skin cancer.

Resection of metastases is feasible in several circumstances. The two most common are isolated liver metastases from colon cancer and pulmonary metastases (especially from sarcomas sensitive to chemotherapy).

Palliative surgery is used to relieve or prevent a specific symptom of a cancer patient but without the intent to cure. An example is removal of an obstructing or bleeding colon cancer in a patient with liver metastases.

Debulking is the removal of the majority of a tumor, leaving residual disease. The rationale is that the remaining, smaller number of cancer cells will be more susceptible to chemotherapy or radiation therapy. It appears to be useful for advanced ovarian cancers.

Section B: Problems and Complications

V Postoperative Complications

Postoperative complications can be associated with any operation or can be related to a specific kind of surgery. The latter types are discussed in the relevant chapters, whereas general types of complications are discussed here. Thrombophlebitis and pulmonary embolus , which are common postoperative complications, are discussed briefly here and in detail in Chapter 8. Most surgical complications develop in relation to some event that occurs in the operating room, emphasizing the fact that prevention is the best form of management.

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A General principles of management

during the postoperative period are important both in preventing potential complications and in allowing early detection of problems that do develop. These principles include:

Daily or more frequent examination of the patient , including the surgical wound.

Removal of all surgical tubes as soon as possible.

Early ambulation of the patient.

Close monitoring of fluid balance and electrolyte levels.

Adequate but not excessive pain medication.

Good nursing care.

B

Postoperative fever occurs in typical patterns, and the “5W's” mnemonic is useful

W ind. Pulmonary complications, which typically occur earliest, on postoperative days 1–3.

Atelectasis is the usual problem and is treated with coughing, deep breathing, ambulation, and incentive spirometry. Antibiotics should not be given unless evidence of infection is present. For a collapsed pulmonary

Attending to fluid balance and weighing the patient daily should prevent this problem.

VI Surgical Infections

Surgical infections can be defined as infections that require surgical intervention to resolve completely or infections that develop as a complication of surgery. Some are in both categories.

A Overview

Characteristics of surgical infections

They usually involve a penetrating injury (e.g., from trauma), a perforating injury (e.g., a perforated ulcer), or an operative site (e.g., the surgical wound).

Multiple organisms are often present.

Treatment may require surgical drainage of the infection or debridement of necrotic or grossly contaminated tissue; antibiotics alone will not resolve the infection.

Surgical wound infections

The incidence of wound infections is related directly to the nature of the surgical procedure performed. The classification of wounds by extent of contamination is described in Chapter 1, V C.

Clinical presentation. Wound infection often presents as a spiking fever at approximately the fifth to eighth postoperative day. There may be localized wound tenderness, cellulitis, or drainage from the wound.

Treatment. Simple incision and drainage will resolve most postoperative wound infections. Deeper wound infections or extensive necrosis may require operative debridement and antibiotics.

Prosthetic infections. Prostheses are synthetic implantable devices, including vascular grafts, heart valves, artificial joints, fascial mesh replacements, and metallic bone supports.

Clinical presentation. An infected prosthesis usually causes symptoms of either local infection or generalized sepsis. The most common organisms infecting prostheses are staphylococci; these infections are life threatening.

Treatment. Prophylactic antibiotics are always used when implanting a prosthesis; however, an infected prosthesis usually cannot be sterilized with antibiotics and, therefore, removal of the prosthesis is usually necessary.

Prophylactic antibiotics are given during the perioperative period to combat bacterial contamination of tissues that occurs during the operative procedure. The general rules for the use of prophylactic antibiotics are:

The operation must carry a significant risk of a postoperative infection. A clean procedure would not require prophylactic antibiotics, but the following situations would:

A procedure in which a prosthesis is to be implanted

Clean -contaminated procedures, where a nonsterile area is entered; e.g., the respiratory or upper GI tract

Contaminated procedures, such as colon or rectal surgery

The antibiotics used should be effective against the pathogens likely to be present in the operative site.

The antibiotics must reach an effective tissue level at the time of the incision. Therefore, they should be given 1–2 hours before surgery.

The antibiotics should be given for only 6–24 hours after surgery. Longer -lasting regimens offer no additional protection and carry risks of superinfection.

The benefits of the prophylactic antibiotic should outweigh its potential dangers, such as allergic reactions or

the risk of bacterial or fungal superinfections from overgrowth of pathogens.

B Abscesses

Cutaneous abscesses

Types

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Furuncles (boils) are cutaneous staphylococcal abscesses. They are frequently seen with acne and other skin disorders. Bacterial colonization begins in hair follicles and can cause both local cellulitis and abscess formation.

Carbuncles are cutaneous abscesses that spread through the dermis into the subcutaneous region. They are common in individuals with diabetes.

Hidradenitis suppurativa is an infection involving the apocrine sweat glands in the axillary, inguinal, and perineal regions. The infection results in chronic abscess formation and often requires complete excision of the apocrine gland -bearing skin to prevent recurrence.

Causative organisms

Staphylococcal organisms (Staphylococcus epidermidis, Staphylococcus aureus) frequently infect cutaneous lesions. Staphylococci usually produce pus , which must be drained to allow healing.

Other organisms, including anaerobic and gram -negative organisms, can also cause cutaneous abscesses. Coliform organisms are often present in axillary, inguinal, and perineal cutaneous abscesses.

Diagnosis. The microbiologic diagnosis is made by incising the abscess, then culturing and Gram staining the pus. Most staphylococcal organisms are resistant to penicillin; therefore, one of the semisynthetic penicillins, erythromycin, a cephalosporin, or a fluoroquinolone should be used.

Treatment

Drainage

Appropriate antibiotic therapy

Wound care with irrigation and debridement when necessary

Excision of the involved area when it contains multiple small abscesses, sinus tracts, or necrotic tissue.

Intra -abdominal abscesses

Causes

Extrinsic causes include penetrating trauma and surgical procedures.

Intrinsic causes include perforation of a hollow viscus, such as the appendix or duodenum; seeding of bacteria from a source outside the abdomen, e.g., tubo -ovarian abscess; or ischemia and infarction of tissue within the abdomen.

The most common sites are the

Subphrenic space

Subhepatic space

Lateral gutters posteriorly

Pelvis

Periappendiceal or pericolonic areas.

Multiple abscesses are present in up to 15% of cases.

Signs and symptoms of abdominal abscesses are fever, pain, and leukocytosis.

These abscesses may be large and usually produce spiking fevers.

Postoperative abscesses usually produce fever during the second postoperative week.

When there is a delay in seeking medical attention or a delay in diagnosis, patients may present with generalized sepsis.

GI bleeding or pulmonary, renal, or hepatic failure may occur.

Diagnosis. The key to an expeditious diagnosis is a high index of suspicion.

The patient may have tenderness or an abdominal mass, but often no physical findings are present (particularly with a pelvic abscess).

Ultrasonography and CT scan are essential for diagnosis.

Treatment

The mainstay of intra -abdominal abscess treatment is drainage.

Diagnosis and localization with imaging studies allows proper choice of modality.

Unilocular and accessible abscesses can be drained percutaneously with radiologic guidance.

Abscesses that are complex, multilocular, include significant amounts of necrotic debris, or are inaccessible require surgical drainage.

Ideally, drainage is performed without contaminating the general peritoneal cavity.

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Pelvic abscesses may be drained transrectally or through the superior vagina.

Subphrenic abscesses may be drained posteriorly through a twelfth rib approach.

C

Cellulitis is inflammation of the dermal and subcutaneous tissues secondary to nonsuppurative bacterial invasion. It may result from a puncture wound or any other type of skin break.

Signs and symptoms

Cellulitis produces redness, edema, and localized tenderness. Fever and leukocytosis are usually present.

The bacteria may also infect the lymphatics, resulting in red, tender streaks on an extremity (lymphangitis).

A deep abscess can result in overlying cellulitis and should be suspected when a patient does not rapidly respond to antibiotics.

Treatment. The usual organism is a Streptococcus , which is almost always sensitive to penicillin.

D Tetanus prophylaxis

Active immunization with tetanus toxoid injections given in the recommended schedule results in a protective titer within 30 days. This immunization is usually given in infancy (with the diphtheria-pertussis -tetanus shots) or during military induction. A booster dose every 10 years is recommended.

Prophylaxis at the time of injury

Any person with a penetrating injury must receive tetanus prophylaxis if previous immunization cannot be documented.

A previously immunized person should be given a booster dose if not given within the past 5 years.

A patient with a clean injury who has never been immunized may be given the first of three immunizing doses, but the patient must receive the subsequent two doses (4–6 weeks and 6–12 months later, respectively).

A patient with a dirty wound who has never been immunized should be given passive immunization with human tetanus immune globulin intramuscularly.

The protection lasts approximately 1 month.

The first dose of tetanus toxoid may be given at the same time, but it should be given at a separate intramuscular site.

Adequate debridement of devitalized tissue and removal of all foreign debris are also essential.

The value of antibiotics , particularly penicillin, for the prophylaxis of tetanus -prone wounds is unproven. However, for patients who have a suspected Clostridium tetani infection or extensive necrosis, prophylactic penicillin should be given in high doses.

E

Necrotizing fasciitis is a rapidly progressive bacterial infection in which multiple organisms invade fascial planes. The infection travels rapidly and causes vascular thrombosis as it progresses, resulting in necrosis of the tissue involved. The overlying skin may appear normal, leading the clinician to underestimate the severity of the infection. Necrotizing fasciitis may result from a puncture wound, a surgical wound, or open trauma.

Signs and symptoms

Hemorrhagic bullae may develop on the skin, accompanied by edema and redness, and crepitus may be present; however, the skin also may appear normal.

The patient shows signs of progressive toxicity (fever, tachycardia) and may have localized wound pain.

The necrotic wound or tissue involved has a foul -smelling serous discharge.

A plain radiograph of the wound area may reveal air in the soft tissues. CT scans will also show air in the tissues.

Diagnosis. Gram stain reveals multiple organisms, which act synergistically, giving the fasciitis its rapidly progressive and destructive character, including:

Microaerophilic streptococci

Staphylococci

Gram-negative aerobes and anaerobes.

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Treatment is surgical, and early diagnosis is extremely important.

The surgeon attempts to remove all infected or devitalized tissue at the first debridement because remaining necrotic tissue will allow the process to continue.

The removal of large amounts of skin and surrounding tissue and, occasionally, amputation of an extremity may be required.

Daily debridement may be needed.

Appropriate antibiotics in high doses are required.

This infection is life threatening , and prompt treatment is essential.

F

Clostridial myositis and cellulitis (gas gangrene) is most commonly caused by Clostridium perfringens.

Characteristics of wounds susceptible to develop this condition include the following:

Extensive tissue destruction has occurred

Marked impairment of the local blood supply from the injury itself, from complications of the injury (e.g., vascular thrombosis), or from iatrogenic causes (e.g., an overly tight orthopedic cast)

The wound is grossly contaminated

There has been a delay in treatment (usually more than 6 hours)

The patient has a pre-existing condition causing immunologic incompetence, such as corticosteroid drug therapy or poorly controlled diabetes.

Clinical presentation

The onset of symptoms is usually 48 hours after injury but may occur as early as 6 hours after injury.

The most common complaint, severe pain at the site of injury, is due to the rapidly infiltrating infection. This symptom may be obscured if the patient is receiving narcotics. If a surgical patient requires an increase in narcotics, the wound should be examined before the narcotics are increased.

The pulse is rapid and thready. The patient appears diaphoretic, pale, weak, and confused or delirious. The temperature is often, but not always, elevated.

The wound is more tender to the touch than is the usual postoperative wound. The skin may appear normal, but the wound usually drains a brownish serous fluid with a foul odor. Crepitus may appear around the wound edges but is often a late sign.

Blood studies reveal a falling hematocrit and a rising bilirubin from hemolysis. The white blood count may be mildly elevated.

Gram stain of the wound discharge reveals Gram -positive bacilli with spores. Numerous red blood cells are present, but few white cells are present.

A plain x-ray of the wound area may reveal air in the soft tissues.

Treatment. Adequate debridement at the time of initial injury is important for prophylaxis. Treatment for established clostridial infection includes extensive debridement within the tissue planes involved and antibiotics, especially penicillin. If extensive soft tissue necrosis is present in an extremity, amputation may be necessary.

Hyperbaric oxygen therapy is used, but its value is unproven.

Human tetanus immune globulin will not prevent or treat gas gangrene.

Delay in treatment to consider further diagnostic procedures or to observe the patient's course is usually

catastrophic.

G Infections after surgery

Gastrointestinal surgery

Upper GI tract surgery

The rate of serious infections after operations on the upper GI tract is 5%–15%.

The oral cavity is colonized by large numbers of aerobic and anaerobic bacteria. These bacteria are generally killed in the low pH environment of the stomach.

Gastric cultures become positive when obstruction or blood is present; therefore, prophylactic antibiotics should be used in these settings.

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Patients without the protective low gastric pH, e.g., those taking antiulcer medications (H 2 -blockers,

proton pump inhibitors, etc.), achlorhydria, or gastric malignancy also should be given prophylactic antibiotics.

The usual antibiotics are a cephalosporin or a fluoroquinolone to cover both aerobes and anaerobes.

Biliary tract surgery

The biliary tree is not colonized with bacteria in the normal individual. The colonization rate rises to 15%–30% for patients with chronic calculous cholecystitis and to over 80% in patients with common duct obstruction. Of those patients with positive cultures:

Escherichia coli is present in over one half of the cases; other gram -negative organisms account for most of the remainder.

Streptococcus faecalis, the aerobic gram -positive enterococcus, may also be present, and Salmonella strains are occasionally present. Anaerobic organisms, especially C. perfringens , are present in up to 20% of cases.

For elective cholecystectomy, simple prophylaxis with a cephalosporin is adequate.

Therapeutic antibiotics are needed in patients with common duct stones, cholangitis, and empyema or gangrene of the gallbladder. A cephalosporin or penicillin -combination should be given.

Colonic and rectal surgery

Wound and intraperitoneal infections often (6%–60%) follow colorectal surgery.

Normal human colonic flora is composed of both aerobes and anaerobes.

Aerobes are present at levels of 10 8 –10 9 bacteria per gram of stool. E. coli , the most common aerobe, is the organism most often found in wound infections after colonic surgery.

Anaerobes are present at levels of 10 11 bacteria per gram of stool (1000-fold greater numbers than those for aerobes). Many types are present, but Bacteroides fragilis is the most common and is the usual cause of anaerobic wound infections.

Mixed aerobic and anaerobic infections are typical.

An effective preoperative regimen combines the removal of gross feces (mechanical preparation of the bowel) with the use of oral nonabsorbable antibiotics.

Mechanical removal of the feces is the most important factor in lowering the bacterial counts and the incidence of wound infections. Regimens include aggressive purgation—with potent oral laxatives such as mannitol or polyethylene glycol—plus enemas.

Antibiotic prophylaxis will lower the incidence of wound infection only after adequate mechanical preparation. To be effective, the antibiotics must be active against both aerobic and anaerobic organisms.

Oral antibiotics , such as neomycin and erythromycin base started 10–22 hours before surgery, result in maximal bacterial suppression at the time of surgery. Longer treatment periods allow resistant bacterial overgrowth.

IV antibiotics may further lower the incidence of wound infection.

Preparation of the colon and rectum should be carried out before all elective operations unless a high-grade (complete) obstruction is present. An obstruction will compromise the mechanical bowel preparation and may require the creation of a proximal stoma to relieve the obstruction.

In emergency procedures (e.g., after trauma) when no bowel preparation is possible, IV antibiotics should be given, and the wound should not be closed primarily. Colonic anastomoses are riskier in these situations than in elective situations.

Gynecologic surgeries are usually clean-contaminated procedures, and prophylactic antibiotics are appropriate.

Urologic surgery

Although the normal urinary tract is sterile, the most common pathogen encountered is E. coli , followed by other gram -negative rods and enterococci.

The general principle is that elective surgery should be postponed until any infection has been successfully treated; this principle is especially true for urologic surgery.

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Chronic indwelling tubes (e.g., suprapubic bladder catheters nephrostomies) are generally colonized with bacteria but do not require antibiotic therapy unless the patient has a symptomatic local infection, generalized sepsis, or catheter obstruction; or unless a urea -splitting organism, such as Proteus , is present.

In the presence of urinary tract pathology , it may be impossible to sterilize the urine. Therefore, antibiotics are used perioperatively as both treatment and prophylaxis.

Congenital. Distal tracheoesophageal fistula with esophageal atresia is the most important congenital fistula (see Chapter 29, IV ).

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TABLE 2-3 Approximate Electrolyte Content of Gastrointestinal Secretions

Trauma or operative injury. Traumatic injury or anastomotic breakdown can produce fistulization. Examples include a colocutaneous fistula from an anastomotic leak or a pancreaticocutaneous fistula complicating a splenectomy.

Inflammation. Crohn's disease can cause many fistulas, including enterovesical (i.e., small bowel to bladder) and ileosigmoid.

Malignancy. Fistulas can develop when a tumor destroys tissue. For example, a colovesical fistula can occur if a sigmoid colon cancer erodes into the urinary bladder.

Radiation damage. An enterovaginal fistula can develop after pelvic irradiation for cervical carcinoma.

C Complications

Fluid and electrolyte imbalances are frequent complications of fistulas, especially those involving the proximal bowel or pancreas. The electrolyte content of various GI secretions is shown in Table 2-3. Electrolyte losses can be directly measured from a sample of the fistula drainage. For example, a pancreatic fistula that drains 700 mL of bicarbonate-rich fluid a day can produce dehydration and metabolic acidosis.

Sepsis, a frequent accompaniment of fistulas, occurs when the contents of an organ leak and contaminate sterile spaces (e.g., peritoneum or pleura).

Skin excoriation can occur when intestinal secretions drain onto the abdominal skin. This skin disruption can be painful and result in cellulitis or sepsis.

Malnutrition can develop either from inadequate absorption of nutrients due to short circuiting of the bowel or external loss of ingested food (e.g., gastrocolic fistula and high-output enterocutaneous fistula, respectively) or because of increased caloric needs from associated infection or stress.

Hemorrhage is an infrequent but potentially life -threatening complication of enteric fistulas. It occurs when a fistula

erodes into a mesenteric blood vessel, causing severe bleeding.

D Evaluation

Management of the patient with an enteric fistula requires knowledge of the anatomy, etiology, and physiology of the defect.

History and physical examination

The history can provide useful etiologic information, e.g., diverticulitis or Crohn's disease, or pneumaturia.

Examining the patient provides information about the location of an external fistula and the character of its drainage. The status of hydration and malnutrition should be assessed.

The volume of drainage must be determined.

Radiographic studies are vital in determining the anatomy. Contrast material may be administered by mouth, by rectum, or directly into the fistula (fistulogram or sinogram ).

Ultrasonography, CT scan, and MRI can be useful in locating an undrained collection (i.e., an abscess), which may be associated with the fistula and if undrained could be a source of infection.

Radiographs should also be used to exclude the presence of obstruction distal to the fistula (see VII E 6 f). P.60

Laboratory tests on the drainage are useful to determine electrolyte losses from the fistula, and bacteriologic

cultures should be obtained in patients with possible sepsis.

E Management

Hydration and correction of electrolyte disturbances require urgent attention.

Control of infection requires immediate attention. Antibiotics and drainage of abscesses are usually required before patients improve: A fistula will not heal in the presence of an infected collection.

Control of external drainage helps to minimize further morbidity. Suction catheters, drains, collection bags, or operative diversion may be useful in protecting body surfaces from irritation. Bowel rest, provided by prolonged fasting, often diminishes GI fluid losses.

Correction of malnutrition should begin as soon as the patient is stabilized. Most patients require parenteral nutrition. Occasionally, tube feedings of a low -residue diet, or even oral feedings, will be possible.

Therapy to inhibit organ -specific secretions is used when appropriate.

For the stomach: H2 -blockers or proton pump inhibitors

For the pancreas: octreotide.

“Spontaneous closure” will occur in most patients with conservative therapy to minimize drainage and with appropriate nutrition. Closure with conservative measures takes 2–8 weeks. However, spontaneous closure is unlikely, and operative repair is required when any of the following is present, using the mnemonic “FRIEND”:

F oreign body at the fistula

Radiation injury at the fistula

I njured bowel or inflammatory bowel disease at the fistula site

E pithelialization of the fistula tract

Neoplasia (or cancer) at the fistula

Distal obstruction beyond the fistula.

Operative repair is best performed electively in a nonseptic, well-nourished patient. Operation typically involves:

Identification of the fistula

Resection of the fistula and damaged bowel

Anastomosis to restore bowel continuity.

F Results

Major improvements in fistula management have occurred in the past 2 decades, with resultant increased survival rates.

Mortality rates. Until the mid 1960s, mortality rates were over 50% for gastric, duodenal, or small bowel fistulas.

Management emphasized early attempts at operative repair before malnutrition developed.

Major causes of death were electrolyte and fluid disturbances, malnutrition, and peritonitis.

Current management should lower the mortality rates to 2%–10%, depending on the etiology of the fistula.

Sepsis and renal failure remain significant causes of death.

Malnutrition and electrolyte disturbances have largely been eliminated as causes of death because of improved techniques for venous access, blood chemistry monitoring, and prolonged parenteral feeding.