• Direct inoculation from instruments and operating personnel

• Airborne bacteria-laden particles

• From the patient’s skin

• From the flora of the patient’s internal viscera, especially large bowel

• Via the bloodstream

• The concentration of organisms in the air

• The size of bacteria-laden particles

• The duration of exposure of the open wound

Minimising infection from operating theatre personnel: Only a modest proportion of wound infections derive from theatre personnel. Bacteria reach the wound via the air or by direct inoculation, often from viscera within the wound. About 30% of healthy people carry Staphylococcus aureus in the nose but pathogenic organisms may also be present in axillae and the perineal area, the last probably being the most important source of wound infections from theatre personnel. In addition, skin abrasions are usually infected, as are skin pustules and boils; thus personnel with these lesions must ensure that they are effectively covered with occlusive dressings or else should not enter the operating area.

Airborne, personnel-derived infection is reduced by changing from potentially contaminated day clothes to clean theatre clothes and shoes which should not be worn outside the theatre complex. Trouser cuffs should be elasticated or tucked into boots. Females should wear trousers instead of dresses, in order to reduce ‘perineal fallout’. Face masks are worn to deflect bacteria-containing droplets in expired air, but most types become ineffective after a very short period, especially when wet. With the exception of nasal Staph. aureus (particularly important in prostheses infection), bacteria derived from the head do not generally cause wound infection. The effectiveness of wearing masks and hair coverings to reduce infection is unknown.

Sterile gloves and gowns are worn by surgeons and staff directly involved in the operation to prevent inoculation of bacteria. Gloves are impermeable to bacteria but hands and forearms need washing before gloving and gowning with antiseptics that persist on the skin. This minimises bacterial contamination if a glove is punctured (as often happens) or the sleeve of the gown becomes wet. The traditional ritual of scrubbing with a brush for 3 minutes is actually less effective than washing the hands thoroughly because it causes microtrauma and brings bacteria to the surface.

Despite the protection given by wearing gloves and gown, the less a wound is handled the better. This principle applies particularly when aseptic conditions are less than ideal. On the ward, minor procedures such as bladder catheterisation or chest drain insertion should be performed using sterile precautions and a no-touch technique. Catheters, for example, should not be handled directly but only within their wrapper or with instruments.

Minimising infection from the patient’s skin: The patient’s skin, especially the perineal area, is the source of up to half of all wound infections. These may be minimised by the following measures:

Reducing infection from internal viscera: The large bowel teems with potentially pathogenic bacteria and the peritoneal cavity inevitably becomes contaminated in any operation where large bowel is opened. Pathogenic bacteria are also found in obstructed small bowel. The same applies to the stomach and small bowel of patients on proton pump inhibitors where the normal bactericidal effect of gastric acid is lost. Great care should be taken at operation to minimise this contamination. Bowel preparation of the colon before operation may help this process. All patients having bowel operations should be given prophylactic antibiotics before operation.

Sterilisation of instruments and other supplies: (see Table 10.1)

In modern surgical practice, infection from instruments, swabs, equipment and intravenous fluids has been virtually eliminated by the use of sterile packs from central sterile supply departments (CSSD). Reusable instruments and drapes are sterilised by high-pressure steam autoclaving according to strict regulations. Most disposable items are purchased in pre-sterilised, sealed packs. Sterilisation in small autoclaves near the operating theatre should only be performed if instruments in short supply are required for successive operations. Sterilisation by any method is ineffective unless all organic material is first removed by thorough cleaning. It is also important to transport soiled instruments promptly to CSSD as proteinaceous material becomes fixed to metal and resistant to removal. This is especially true for small and microsurgical instruments (e.g. in ophthalmology), where channels easily become blocked by organic matter and prevent effective sterilisation.

Instruments which would be damaged by heat, including plastics, cystoscopic lenses, flexible endoscopes and electrical equipment, can be sterilised using a variety of chemical methods such as ethylene oxide gas. The Sterilox method is commonly used for endoscopic instruments that need to be reused several times during a session; the endoscopes are bathed in an electro-chemically activated water system through which an electrical current is passed.

World-wide, many surgical instruments are prepared by boiling water ‘sterilisers’. Boiling water is markedly inferior to other methods but is included here as it may be the only practical method in developing countries because of cost and technical difficulties. Boiling water kills most vegetative organisms within 15 minutes but spores are not killed. All organic debris should, as always, be scrupulously removed first, then the instruments immersed in visibly boiling water, returned to the boil and boiled continuously for at least 30 minutes to ensure hepatitis and human immunodeficiency viruses are destroyed.

Prevention of cross-infection (nosocomial infection): Cross-infection is the term used for infection transmitted from other patients in the nearby hospital environment and should be distinguished from colonisation with other patients’ bacteria. Cross-infection is mainly spread via staff, medical equipment, food or ward furnishings. Doctors are probably the worst offenders as regards transfer of infection—by removing dressings to inspect wounds in the open ward, by failing to cleanse hands between patients and by careless aseptic technique when performing ward procedures such as bladder catheterisation. Minimising patient movements between wards and hospital units also decreases cross-infection rates.

A patient with an infection that is potentially dangerous to other patients, such as meticillin-resistant Staph. aureus (MRSA), should be isolated and barrier-nursed in a single room.

Prophylactic antibiotics: Despite using the best aseptic techniques, some operations carry a high risk of wound infection as well as other infective complications; these can be dramatically reduced by using prophylactic antibiotics. The chosen antibiotics should be matched to the organisms likely to occur in the area of the operation and should be bactericidal rather than bacteriostatic (see Table 10.2). The relative risk of postoperative infection in different types of operation is summarised in Box 10.2.

As a general principle, pre or peroperative prophylactic antibiotics are indicated if the anticipated risk of infection exceeds 10%, e.g. all emergency abdominal surgery and all elective colonic operations. Prophylactic antibiotics are also used by many surgeons for operations in the 5–10% risk category, e.g. cholecystectomy. Prophylactic antibiotics are also indicated for inherently low-risk cases where the consequences of infection would be catastrophic, e.g. operations employing prosthetic implants, or in patients with mitral stenosis or other cardiac defects at risk of infective endocarditis. Prophylactic antibiotics can reduce postoperative infection rates in high-risk cases by 75%, and may almost entirely eliminate infection where the risk is lower.

In most wound-related infections, the organisms are introduced during the operation and become established during the next 24 hours. Thus, for prophylactic antibiotics to be effective, high blood levels must be achieved during the operation when contamination occurs. To achieve this, the first dose should be given 1 hour before operation or preferably intravenously at induction of anaesthesia; prophylactic antibiotics should not be given earlier as this may encourage resistant organisms to proliferate (Box 10.3). A single preoperative dose of antibiotic is generally sufficient if it is rapidly bactericidal and the inoculum of bacteria is small; long operations with heavy blood loss, e.g. ruptured abdominal aortic aneurysm, merit a second perioperative dose of antibiotics later in the operation. Longer courses of prophylactic antibiotics are of no advantage.

In general, intravenous antibiotics give the most predictable blood levels and peak tissue levels are achieved within 1 hour of injection. However, for prophylaxis against anaerobes, metronidazole administered rectally gives blood and tissue levels equivalent to intravenous administration but later, 2–4 hours after administration.

General principles: Some form of anaesthesia is needed for almost every surgical procedure, with the aim of preventing pain in all cases, minimising stress for the patient in most, and providing special conditions for some operations, e.g. muscular relaxation in abdominal surgery. The choice of anaesthetic techniques includes topical (surface) anaesthesia, local anaesthetic infiltration or peripheral nerve block, spinal or epidural anaesthesia and general anaesthesia. Methods other than general anaesthesia may be supplemented with intravenous sedation if the patient is anxious or agitated (e.g. with benzodiazepines). Intravenous sedation with these drugs produces relaxation, anxiolysis and amnesia whilst retaining protective reflexes. However, these drugs can also cause unconsciousness and they must be carefully titrated to produce just the desired effects. Intravenous sedation of this type does not provide pain relief; if needed, this is achieved with local anaesthesia or intravenous analgesics.

Choice of anaesthetic technique: Combining local or regional anaesthesia (for pain relief) with general anaesthesia can minimise postoperative respiratory and cardiovascular depression compared with general anaesthesia alone, reducing morbidity. An example is the use of caudal anaesthesia in perineal operations. Local or regional anaesthesia with bupivacaine or levobupivacaine can also be administered during an operation to provide postoperative pain relief; for example, intercostal nerve blocks during an abdominal operation allow more comfortable breathing and coughing, reducing respiratory complications. Another common example is wound infiltration with the same long-acting local anaesthetics. The main factors influencing choice of anaesthesia are summarised in Box 10.4.

Choice of incision: The purpose of most skin incisions is to gain access to underlying tissues or body cavities. When planning an incision, the first concern is to achieve good access and also allow it to be extended if necessary. It must also be sited in such a way that it can be effectively closed to give the best chance of primary healing and the lowest chance of an incisional hernia later. Despite patients’ impressions, the length of an incision (and the number of sutures) has little bearing on the rate of healing, and the success of an operation should not be put at risk by inadequate access.

Secondary considerations in the choice of incision are as follows:

Dissection and handling of deeper tissues: The skin consists of thin epidermis and dense, somewhat thicker dermis, as well as the underlying fatty hypodermis which may be 10 cm or more thick in an obese individual.

Once the skin incision has been made, the scalpel is mainly reserved for incising fascia and other fibrous structures such as breast tissue and very fine dissection. Anatomical detail is exposed and displayed by a combination of blunt and sharp dissection. Blunt dissection involves teasing or stripping tissues apart using fingers, swabs or blunt instruments, following natural tissue planes. Sharp dissection with scissors and forceps or scalpel is used where tissues have to be cut and also to display small structures. Some surgeons prefer sharp to blunt dissection in general, believing it causes less tissue trauma. Most dissection, however, involves a combination of both.

Clipping, ligation and under-running: Ligation or specialised bipolar diathermy is obligatory when large vessels are divided and is desirable for vessels larger than about 1 mm calibre (see Fig. 10.1). If the end of a bleeding vessel cannot be grasped by haemostat forceps, a suture can be used to encircle the vessel and its surrounding tissues, a technique often described as under-running. It is particularly useful for a bleeding artery in the fibrous base of a peptic ulcer.

Diathermy: Diathermy achieves haemostasis by local intravascular coagulation and contraction of the vessel wall caused by heating (-thermy), generated by particular electrical waveforms. However, enough heat is also produced to burn the tissues and these may be needlessly damaged by careless use, particularly near the skin or nerves. Ordinary diathermy is ineffective for large vessels, which should be ligated. There are three main variants of diathermy, illustrated in Figure 10.2, and all three modes are available on modern diathermy machines.

Monopolar diathermy is the most widely used for operative haemostasis but there is wide dispersion of coagulating and heating effects, making it unsuitable for use near nerves and other delicate structures. Since the current passes through the patient’s body, there is a risk of coagulating vessels en passant (e.g. monopolar diathermy used in circumcision may cause penile thrombosis), as well as provoking arrhythmias in patients with cardiac pacemakers. Monopolar diathermy may also result in skin burns at the indifferent electrode plate if skin contact is poor or if the plate becomes wet during operation. To improve contact, hair should be shaved from the skin where the plate is placed.

Bipolar diathermy is used mainly for finer surgery. The current passes only between the blades of the forceps and it requires fairly accurate grasping of the bleeding vessel. It uses low levels of electrical power, there is almost no electrical dispersion from the tip of the forceps and much less heat is generated. The main advantages are minimal tissue damage around the point of coagulation and safety in relation to nearby nerves, blood vessels and cardiac pacemakers. Specialised computer controlled bipolar diathermy is often used for larger vessels during laparoscopic surgery.

Cutting diathermy is mainly used for dividing large masses of muscle (e.g. during thoracotomy or access to the hip joint) and cutting vascular tissues (e.g. breast). The intention is a form of sharp dissection, at the same time coagulating the numerous small blood vessels as the tissue is cut; unfortunately this is not always wholly effective. A blend of cutting and coagulation is sometimes used.

Tourniquet and exsanguination: This technique is used in surgery of the limbs and hands where a bloodless field is desirable. For the whole limb, a pneumatic tourniquet is placed proximally. The limb is exsanguinated by elevation and spiral application of a rubber bandage (Esmark) or a ring exsanguinator from the periphery; the tourniquet is then inflated. Upper limb tourniquets must not be left inflated for more than 30 minutes and lower limb tourniquets for more than about 1 hour to avoid the risk of necrosis.

Pressure: Pressure is a useful means of controlling bleeding until platelet aggregation, reactive vasoconstriction and blood coagulation take over. It can be used for emergency temporary control of severe arterial or venous bleeding but is equally useful for controlling diffuse small-vessel bleeding from a raw area, e.g. liver bed after cholecystectomy. Pressure is usually applied with gauze swabs which must be kept in position for at least 10 minutes. Even if bleeding is not arrested completely, this process usually allows a clearer view and allows haemostasis by standard means.

For intractable bleeding which is not amenable to ligature, diathermy or suture, various resorbable packing materials, e.g. oxidised cellulose, can be left in position until haemostasis occurs, allowing the wound to be closed. If bleeding simply cannot be controlled—for example, after liver injury—the bleeding cavity can be packed with gauze swabs which are left in situ and removed 48–72 hours later at a further operation. Bleeding, once controlled by this method, rarely recurs.

When a raw cavity has been created beneath the skin, external pressure dressings are sometimes a useful method of controlling potential superficial postoperative oozing and minimising haematoma formation.

Types of suture material and needles: Numerous types of suture are available (see Box 10.5), with the most important distinction being between absorbable and non-absorbable materials. The groups can be subdivided into natural and synthetic materials (although natural materials are being phased out) and further subdivided into monofilament and polyfilament (braided) materials. The choice of suture material depends upon the task at hand, the handling qualities and personal preference.

Absorbable versus non-absorbable materials: The strength of absorbable sutures declines at a predictable rate for each type of material, although the suture material remains in the wound long after it has any useful ability to hold tissues together.

In increasing duration of useful strength, the main absorbable materials are:

The eventual elimination of absorbable materials from the body overcomes the problem of a permanent foreign body which can harbour infection. Absorbable sutures are often used in skin to avoid the need for removal; typical applications are minor skin operations, median sternotomies, surgery in children, circumcisions and vasectomies. Polyglycolic acid/polyglactin (undyed) gives good results as the sutures are removed by hydrolysis without inflammation. The modified short-lived polyglactin has ideal properties for skin closure where short suture life is required, e.g. inguinal hernia repair, and the monofilament poliglecaprone 25 (Monocryl) is ideal for situations when longer wound support is required.

Non-absorbable sutures retain most of their strength indefinitely. They are used where the repaired tissues take a long time to reach full strength (e.g. abdominal wall closure) or will be inherently weak (e.g. inguinal and incisional hernia repairs, arterial anastomoses). Non-absorbable sutures are also widely used for skin closure; synthetic monofilament sutures give reasonable cosmetic results and are easily and painlessly removed. Subcuticular sutures, which do not penetrate the epidermis, give excellent cosmetic results.

Natural versus synthetic materials: Catgut has been used as a suture and ligature material since before Roman times, derived from the material used for musical instrument strings. It consists mainly of collagen and is actually made from the dried small bowel submucosa of sheep or cattle. Silk and linen also have a long and distinguished history. Many surgeons believe that silk has the best handling and knotting properties of any material, but it provokes a strong inflammatory response exceeded only by linen. Silk was sometimes used for skin sutures, where its softness means there are no sharp ends to prick nearby skin. In general, natural materials are cheaper than synthetics, a factor of importance in developing countries.

The main advantages of synthetic absorbable suture materials are that they are stronger and provoke little or no inflammatory reaction. There is no risk of biological contamination with prions or viruses and they can be designed to meet specific requirements of absorbability, period of retention of strength, and handling properties.

Non-absorbable synthetic materials, similarly, do not provoke inflammatory reactions. Polyesters, nylon and polypropylene all retain virtually all of their strength over long periods in the tissues; this is particularly important when they are used to suture arterial prostheses where healing alone would not retain the prosthesis.

Monofilament versus polyfilament sutures: Monofilament materials have a smooth surface and can be pulled through the tissues with minimal friction; this makes them easier to insert and remove than polyfilament braided materials. On the other hand, monofilament materials are stiff, springy and more difficult to knot. Braided materials have the best handling qualities, but their interstices are a haven for bacteria. When used at a surface (e.g. skin or bowel wall) they tend to act as a ‘wick’, drawing infected material in. This problem is partly overcome by the manufacturers’ application of surface coatings.

Wire sutures: Metal wire sutures have largely been displaced by non-absorbable synthetics. Stainless steel wire is, however, extensively used in orthopaedic surgery for bone fixation and sometimes for closure of sternotomy wounds in cardiac surgery. It is virtually inert but its main disadvantages are high rates of glove penetration and late breakage due to metal fatigue.

Gauge of suture material: The gauge of suture chosen for a particular task depends largely on practical experience. This takes into account the following factors:

The traditional method of describing suture gauge (US Pharmacopoeia) is confusing for the newcomer and derives from the time when sutures were much thicker than those used today. The finest suture then was designated gauge 1, with gauge 2 and upwards applying to heavier sutures. As finer and finer sutures came into use, the scale had to be taken progressively backwards from 1, i.e. gauges 0, 00 (i.e. 2/0), 000 (3/0) and so on. Nowadays, the finest suture is 11/0, used for extremely delicate surgery such as in the eye. A more rational metric gauge, based on suture diameter, is in use but the traditional gauge is still widely used. A simple guide to the use of different gauges is outlined in Box 10.6.

Types of suture needle: Vast ranges of needles have been designed to accommodate the breadth of different demands of general and specialist surgery and the stringent requirements of microsurgery. Characteristics of needles and broad indications for their use are summarised in Box 10.7 and illustrated in Figure 10.3.

Methods of skin suturing: The objective of skin suturing is to approximate the cut edges so they will heal rapidly, leaving a minimal scar. Edges to be apposed should have been cut in a clean line and perpendicular to the skin surface; ragged or angled edges should be trimmed. The cut edges should be capable of being brought together neatly and without tension; otherwise the wound may break down or the scar slowly stretches, giving an ugly result. To achieve this, it may be necessary to insert a layer of subcutaneous sutures or even mobilise the skin by undercutting in the fatty layer (see Fig. 10.4). Undue laxity should also be avoided by trimming excess skin.

There are many techniques of skin closure, the choice being governed by the nature and site of the operation and by the surgeon’s preference. In general, facial wounds are closed with multiple fine sutures removed after 4 or 5 days. Abdominal and chest wound sutures are generally removed after 7 days, while sutures for wounds on the back are best left for 14 days to minimise wound stretching.

Subcuticular sutures, either non-absorbable or absorbable, are often used for longer wounds in cosmetically sensitive areas, provided the risk of infection is low. Elsewhere, the choice is between interrupted and continuous suture techniques. Interrupted sutures are indicated if there is a risk of infection; if infection develops, some sutures can be removed early to facilitate drainage. If the risk of infection is high, e.g. large bowel perforation, skin wounds are better left open and closed 48–72 hours later by delayed primary closure. The commonly used methods of skin suturing are illustrated in Figure 10.5.

Clips and staples: Stainless steel clips (e.g. Michel clips) have been used for decades for closing skin wounds and are popular for neck incisions after thyroidectomy as they are haemostatic. As the clips do not penetrate skin yet give good edge apposition, the cosmetic result is excellent. Staples are used for both skin closure and bowel surgery. The skin closure devices are similar in concept to ordinary paper staplers, with staples stored in a magazine and applied singly instead of sutures (Fig. 10.6). More complex devices, which apply multiple staples simultaneously, either in a linear or circular fashion, are available for bowel anastomoses and closure of tubular viscera. Some devices have revolutionised surgical practice, e.g. re-anastomosis of colon to rectum after Hartmann’s resection or bronchial stump closure. When used for internal viscera, the staples remain in place indefinitely.

Types of wound dressing: For small surgical wounds, particularly on the face, a dressing is often unnecessary as the linear crust of inflammatory exudate performs this task very well. For other simple wounds, plastic spray dressing is suitable, e.g. Opsite. In most other cases, prepacked adhesive dressings are used, incorporating an absorbent pad with non-stick film in contact with the wound surface. While convenient, these dressings may conceal accumulations of blood, inflammatory exudate or infected discharge. Wound inspection then requires painful removal of the dressing which can be an opportunity for infection to enter. Transparent semipermeable plastic film dressings neatly overcome this problem but are unsuitable for discharging wounds.

A flexible polyamide net coated with soft silicone (e.g. Mepitel) is useful for covering raw areas. This has very low wound adherence and is usually easy to remove. Other dressings include calcium alginate (seaweed origin), hydrocolloids and hydrogels. These dressings offer a better wound environment with increased hydration, fewer dressing changes, easier dressing removal and greater comfort.

Gamgee is a thick cotton wool dressing material enveloped in a thin layer of gauze; this is variously used for padding sites vulnerable to trauma (e.g. amputation stumps) or as pads beneath pressure bandages or as absorbent dressings for leaking wounds. Dry dressings are wads of dressing material (e.g. cotton gauze), usually taped or bandaged in place. Dry dressings need regular replacement and may be prevented from sticking by placing a piece of non-adherent dressing (e.g. Melolin, N/A dressing) against the wound.

Removal of dressings and sutures: Provided the dressing remains clean and dry and the patient afebrile and generally well, there is no need to inspect clean surgical wounds until the time of suture removal. If wound complications are suspected, the dressing should be removed and the wound checked and redressed. If infection is apparent, a wound swab should be taken for culture and sensitivity. Localised abscess formation requires suture removal and probing to effect drainage, whilst spreading cellulitis requires antibiotic therapy in addition.

Skin sutures should be removed as soon as the wound is strong enough to remain intact without support. On the back and around joints, this can take 14 days; on the abdomen, it takes about 7 days (longer in the case of steroid therapy or infection). On the face and neck, healing is rapid and less influenced by functional stresses. Here, sutures can be safely removed after 3–5 days, giving a better cosmetic result.

Management of drains in the postoperative period: Abdominal drains provide a potential route for infection to enter, even though the intra-abdominal pressure nearly always exceeds external pressure. The risk can be minimised by ensuring the drain opens into a sterile environment such as a drainage bag (closed drainage) and by removing the drain as soon as its task is completed. Decisions about removal of drains should rest with the operating surgeon who will undoubtedly have personal preferences.

The general principles of drain management are as follows:

Open or endoscopic biopsy: If major surgery or other therapy is being considered for a suspected malignant lesion, an accurate tissue diagnosis should be made.

Skin lesions can be biopsied by incision under local anaesthesia. Rectal lesions can be biopsied without anaesthesia using forceps through a rigid or flexible sigmoidoscope or colonoscope, while gastric and colonic lesions can be biopsied via a flexible endoscope. Breast lumps or suspicious mammographic lesions can be sampled using percutaneous core needle biopsy or by fine needle aspiration cytology (see below). Gastroscopy allows biopsy of upper GI mucosal lesions as well as lesion of the pancreatic head.

Enlarged lymph nodes can often be diagnosed by incision biopsy or by removing one or more completely for histological examination (excision biopsy), although many units can now obtain satisfactory results by needle biopsy. Lymphadenectomy often requires general anaesthesia, particularly for lumps in the neck.

Biopsy guided by ultrasound or CT scanning: Abdominal masses such as liver metastases or pancreatic lesions can be biopsied percutaneously with the aid of ultrasound or CT scanning. The suspicious lesion is first located as an image and then a biopsy needle is guided into it with the help of further imaging. The technique can be used to sample abdominal masses or suspicious para-aortic lymph nodes in staging lymphomas or following treatment for testicular germ cell tumours.

Cytology: Special staining techniques for malignant cells can be applied to material obtained by fine needle aspiration. Cytological diagnosis requires particular laboratory skills but often permits accurate diagnosis (e.g. of malignancy), which renders more invasive investigations unnecessary. A negative cytological result, however, must be interpreted with great caution because it may be due to sampling error.

Cytological diagnosis can be useful for the following:

Local anaesthesia for skin lesions: The usual method of administration is by infiltration (injection) of local anaesthetic agents (e.g. lidocaine 0.5% or 1%) into the skin surrounding the lesion. Between 1 and 10 ml of solution is usually required, but care must be taken to remain within maximum safe dosages (see Table 10.3). A vasoconstrictor (e.g. adrenaline (epinephrine) 1 in 200 000) may be incorporated to reduce vascularity in the operative field, but this must never be used on the extreme peripheries, i.e. fingers, toes, penis or nose, because of the risk of ischaemic necrosis. The injecting needle should be as fine as possible and inserted into the skin as few times as possible to avoid causing unnecessary pain. Before each injection, aspiration is attempted to ensure that the solution is not injected directly into a blood vessel as intravascular injection may cause systemic toxicity. Methods of infiltration of local anaesthetic are illustrated in Figure 10.7.

Biopsy techniques:

Destruction of lesions by diathermy, electrocautery, cryocautery or curettage: These techniques are used for small lesions where there is no clinical suspicion of malignancy or for small basal cell carcinomas where a histological diagnosis is not required; the lesion is destroyed in the process of removal. Local anaesthesia is needed except for cryocautery, which is relatively painless.

Removal of cysts: A cyst is a fluid-filled lesion, lined by epithelium and usually encapsulated by a condensation of fibrous tissue. The aim of treatment is to remove the whole epithelial lining because any remnant leads to recurrence. The technique of removal is outlined in Figure 10.10. Ideally, the cyst is dissected out intact without puncturing the cavity. If this occurs, the cyst collapses, making it difficult to identify and remove the epithelial lining. Inflamed cysts are best simply drained and excised later when the inflammation has settled.

Management of dirty or contaminated wounds: Major soft tissue injuries result in crushing and tearing of tissues, leaving devascularised areas and deep impregnation with soil, road grit or fragments of clothing. If such a wound is merely sutured, pyogenic infection is certain, and there is a serious risk of gas gangrene or tetanus.

The principles of managing these wounds were first established during the First World War, as follows:

Tissue transfer techniques: Obtaining satisfactory skin cover is a key problem in plastic surgery, and other tissues such as fat and muscle cannot satisfactorily be transferred without revascularisation. Free transplantation of full-thickness skin (other than tiny grafts) or any other tissue other than bone without revascularisation is usually unsuccessful.

Tissue transfer can be achieved in three main ways:

Skin grafts: Split skin (Thiersch) grafting involves transplanting a very thin layer of skin consisting of little more than epidermis, which has no blood supply of its own. It depends on nutrition from the recipient bed for its survival. Split skin grafts are commonly employed for burns and after wide excision of skin lesions, provided there is a recipient base of healthy tissue. The donor site heals rapidly since small islands of epithelium are left behind (see Fig. 10.11). The donor site is potentially more painful than the recipient but pain is well controlled if the donor site is dressed immediately with hydrogel or similar dressings. These are left in position for 7–10 days until the wound has epithelialised. Grafts fail because of sliding or shearing movement, or lifting off by haematoma or infection. Dressings exerting mild pressure such as a ‘sponge tie-over’ aim to reduce this. Creating a ‘mesh’ of the graft with a device to make multiple regular perforations helps the graft attach in certain circumstances as it allows free drainage through the perforations. Meshing also allows a graft to be expanded to cover a greater area but gives a poor cosmetic result.

Full thickness (Wolfe) grafts have some advantages for small skin grafts. They do not contract and usually have a better colour match. Donor sites include skin from behind the ear (post-auricular), where the defect can be closed primarily. This can be used for lower eyelid or finger tip reconstruction. However, these grafts pick up blood supply less readily than split skin and so are restricted to reconstructing small areas. See also pinch grafts (Fig. 10.11).

Vascularised flaps: Skin grafts cannot be used where there is a cavity, or bare bone or cartilage and these are absolute indications for flap repair. Flaps can also give good cosmesis, e.g. after skin cancer excision on the face. A flap has a blood supply of its own and is not a graft. The blood supply reaches the flap via its base, the vascular pedicle. Flaps can be advanced, rotated or transposed into the defect and this alone may provide sufficient mobility to close a moderate defect. If flap rotation produces a new defect, this clean area can usually be covered with a split skin graft.

The early random flaps, devised by Gillies, were limited in scope because there was no dominant blood supply and this prevented construction of a flap longer than 2 : 1 ratio to breadth. Later it was realised that longer flaps could be created by ‘axialising’ them. Most flaps are now axial, using recognised anatomical sites to ensure a blood supply running the full length. An early technique was the pedicle flap, a flap of skin raised and formed into a tube while initially remaining attached to its site of origin at both ends.

Axial flaps are selected according to the site of the defect and the tissues needed. A series of flaps have now been described, based on detailed anatomical studies of blood supply. Flaps may be cutaneous (e.g. forehead flap), fasciocutaneous (e.g. the ‘Chinese’ radial forearm flap), myocutaneous (e.g. latissimus dorsi, pectoralis major), TRAM (transverse rectus abdominis myocutaneous—often used for breast reconstruction), and osseous (e.g. fibula, radius, iliac crest and rib).

Free flaps: In free tissue transfer, a carefully planned piece of tissue is first dissected out, complete with at least one main artery and vein; axial flap sites are often suitable. The whole flap is then relocated to the recipient site where the vessels are anastomosed to a suitable local artery and vein by microvascular anastomoses. The donor site can often be closed primarily or else covered with a split skin graft. Examples are the radial forearm flap which supplies bone, muscle and skin (often used for mandibular and intra-oral reconstruction), and the big toe which can be used to replace a lost thumb.

Advantages of laparoscopic surgery: The advantages of laparoscopic surgery go well beyond simply avoiding large painful wounds to give better cosmesis and less postoperative pain:

Risks and complications: Certain complications are common to open and laparoscopic surgery, but laparoscopic operations carry their own particular risks. Specific problems include:

Technique of laparoscopy: Laparoscopy is usually performed under general anaesthesia, most often with muscle relaxation to allow full and safe insufflation of the abdominal cavity. A pneumoperitoneum is first created by introducing carbon dioxide under controlled pressure to lift the abdominal wall away from the viscera, allowing inspection of the peritoneal cavity.

Gas is most safely introduced via a blunt cannula placed by an open technique to enable direct visualisation of the peritoneal contents. The technique has largely replaced ‘blind’ insufflation via a Veress needle which has a significant risk of vascular injury. The gas pressure should be kept as low as possible while maintaining a satisfactory view, in order to minimise cardiac and respiratory risks. A 5 or 10 mm diameter laparoscope with video camera is then introduced into the abdominal cavity, displaying the image on monitors.

Most laparoscopic procedures need additional cannulae (trocars) through which to pass diathermy hooks, graspers, needle holders, clip appliers and linear staplers. These secondary trocars are inserted through new access points under direct vision from within the abdomen to prevent injury to bowel and other viscera. Different operations each require different port placements. Preferences vary from surgeon to surgeon and port siting also depends on the particular conditions of the operation; for example, cholecystectomy in an obese patient necessitates different port sites from those used in a slim patient.

The laparoscopic operation is performed by an operator and one or more assistants, all observing progress on monitors. Sharp or blunt dissection may be employed as in open surgery. Sharp dissection uses laparoscopic scissors whilst blunt dissection is carried out using fine dissecting forceps (‘Petolins’ or ‘Marylands’), laparoscopic gauze pledgets or the tip of a suction probe. Blunt dissection tears rather than cuts small vessels, deliberately causing minor tissue damage that rapidly activates the coagulation cascade and causes spontaneous cessation of bleeding. This is safer than sharp dissection which may require (potentially excessive) use of diathermy. Haemostasis still requires diathermy and this must be cautiously used to prevent arcing to adjacent organs. Increasingly, safer alternatives are being used such as bipolar diathermy forceps or the harmonic scalpel, which uses ultrasound to coagulate and cut vessels and tissue.

In laparoscopic-assisted surgery, for example colectomy, a large part of the dissection is performed laparoscopically and then a small abdominal incision is made to deliver the resected specimen.

After operation, patients experience abdominal discomfort at trocar insertion sites and shoulder discomfort from retained gas in the peritoneal cavity. Few restrictions are placed on the patient after discharge; he or she can return to work as soon as comfortable, often after a few days.

Robotic-assisted surgery: Robotically assisted surgical systems are increasingly being used for certain technically challenging operations such as laparoscopic prostatectomy and cardiothoracic operations. These robots are not autonomous but aid the surgeon who sits at a remote console (which may be close to the patient or far away). The surgeon very precisely controls the robotic manipulation of laparoscopic instruments, previously inserted into the anaesthetised patient, via the surgical arm unit. The imaging system provides three-dimensional vision. The da Vinci system allows manipulation of all instruments whilst other simpler systems just control the camera.

Potential benefits include increased precision of movement with ‘smoothing’ of tremor, prevention of fatigue in long operations and perhaps eventually the need for fewer assistants in the theatre. In the longer term, a surgeon could, at least theoretically, operate on a patient many kilometres away by tele-surgery. Disadvantages of robotic surgery include the high capital cost (currently around $1–1.5 million), complete lack of any tactile feedback for the surgeon and long set-up times for individual patients.

Diagnostic laparoscopy: Diagnostic laparoscopy has long been used by surgeons for assessing chronic liver disease and ascites of unknown origin. Advances in instrumentation and imaging now allow surgeons to perform abdominal exploration almost as thoroughly as is possible via a long laparotomy incision. A key application is for staging gastric or pancreatic cancer to assess operability. This is achieved by inspection, by obtaining peritoneal washings for cytology and by performing biopsies. By this method, patients with incurable disease can be spared the trauma of exploratory open surgery (Box 10.9). Diagnostic laparoscopy is valuable for assessing right iliac fossa pain, particularly in women of menstruating age. The procedure allows more accurate assessment of the gynaecological organs, improves diagnostic accuracy and minimises negative appendicectomy rates.

Therapeutic laparoscopy: Laparoscopic cholecystectomy is already the standard operation for removal of the gall bladder, both in the elective and the emergency situation (described in Ch. 20). Other procedures described below and listed in Box 10.10 are becoming standard operations in the armoury of laparoscopic surgeons.

Laparoscopic surgery for obesity: (Fig. 10.12)

In recent years there has been a major expansion in laparoscopic surgery for obesity (bariatric surgery). The most common technique involves placing an adjustable restrictive silicone band around the upper part of the stomach to create a small proximal pouch that causes early satiety. Results are excellent in carefully selected, well-motivated patients who have good support and follow-up. More radical bariatric operations such as gastric bypass and biliary-pancreatic diversion (BPD) operations are also being performed laparoscopically. These operations achieve greater weight loss and more rapid regression of diabetes but may carry higher rates of morbidity and mortality, largely operator-dependent.

• Vascular (e.g. aneurysm, arteriovenous malformation and stroke)

• Paediatric (e.g. hydrocephalus, tumours and congenital anomalies)

• Spinal (e.g. degenerative disease and tumours)

• Oncology (e.g. glioma, meningioma and metastases)

• Functional (e.g. movement disorders, chronic pain and epilepsy)

• Skull base (e.g. acoustic neuroma, meningioma and chordoma)

Intraoperative considerations: Good intraoperative care and attention to detail allows the operation to proceed safely. ‘Special considerations’ for neurosurgical patients are shown in Table 10.4.

Postoperative considerations: Patients should be recovered in a monitored environment with regular neurological observations. The surgeon should be informed of any neurological deterioration. Depressed consciousness is usually an early sign of rising intracranial pressure. Pupillary dilatation and autonomic changes occur late (e.g. Cushing’s reflex).

Postoperative seizures, reduced conscious level or altered neurology may herald intracranial complications such as oedema or bleeding. Repeat CT is needed after stabilising blood pressure and oxygenation. Sedating analgesics should generally be avoided. Paracetamol and codeine phosphate or small doses of morphine may be appropriate. NSAIDs impair platelet function and should be avoided early on in high-risk patients.

Intravenous fluid needs careful consideration; dextrose may increase cerebral oedema and 0.9% saline or Hartmann’s solution is usually administered. Plasma sodium abnormalities are relatively common in neurosurgical patients and need investigation. These include the syndrome of inappropriate antidiuretic hormone hypersecretion (SIADH), which causes hyponatraemia and sometimes fluid overload, and diabetes insipidus (DI) which causes polyuria and polydipsia by diminishing the ability to concentrate urine.

Treatment of communicating hydrocephalus: This can be relieved temporarily via lumbar puncture (but never in non-communicating hydrocephalus). Long-term management requires diversion by insertion of a shunt as described below.

Treatment of non-communicating hydrocephalus: If secondary to tumour, this may respond to dexamethasone to temporise before tumour removal. Otherwise the obstruction needs to be bypassed by endoscopic third ventriculostomy, insertion of an external ventricular drain, or creation of a permanent CSF diversion with a shunt. Shunting is usually via a catheter between lateral ventricle and peritoneum with a pressure regulating valve.

Bone: Bone is composed of an organic and an inorganic matrix. It undergoes continual adjustment as cells are remodelled and elements refreshed in response to external stimuli. The skeleton is a living organ providing support for muscles and tendons, it has haemopoetic capacity, and it is a calcium reservoir.

Bone structure includes cortical and trabecular components. A solid shell of cortical bone is strong in compression and resists bending forces. Mature cortical bone is arranged in lamellae or layers with vascular channels running through. Its precursor is immature woven bone, seen in healing and in the growing skeleton. Its organisation is random without heed to external stresses.

Bone metabolism involves complicated homeostasis of its matrix (governed by physical stresses), plus regulation of minerals and ions, principally calcium and phosphate. The inorganic component is largely crystalline calcium phosphate and hydroxyapatite, and a feedback loop controls mineralisation and turnover, involving serum ion levels, vitamin D₃, parathormone and calcitonin (see Fig. 49.10, p. 611).

The organic matrix of bone is largely composed of type I collagen, with types V and XI in small amounts contributing to flexibility and strength. Also found are bone morphogenic proteins (BMP 1–17), and cytokines and signallers (interleukin 1 and 6 and insulin-like growth factor).

Articular cartilage: Articular cartilage provides a near frictionless interface between bones to facilitate movement. Synovial joints are covered with hyaline cartilage, a special tissue composed of chondrocytes bound in an extracellular matrix. The matrix is layered tangentially and radially throughout the cartilage; 90% of this collagen is type II.

Hyaline cartilage has very poor healing ability. It is aneural, avascular and alymphatic, and derives nourishment by osmosis from synovial fluid. Superficial abrasions or injuries provoke no healing response and result in permanent damage. Deeper injuries that reach the capillary bed of the bone cause clot formation and later repair with fibrocartilage. Healing never perfectly restores the initial hyaline cartilage or its specialised smooth surface.

Osteoarthritis: Osteoarthritis (OA) is an idiopathic disorder of joint wear. Over the lifetime of a joint, the hyaline cartilage tends to wear out causing pain and stiffness. The process is governed by genetic, developmental and other factors that are not yet completely understood. Some joints such as hip and knee are often affected, whereas others (e.g. ankle) rarely wear out. Some hips wear out because of imperfect articulation or development from birth. It is not yet known why some individuals are plagued by widespread osteoarthritis in their 50s and others have little or none in their 80s. Treatment includes palliative analgesia and often, ultimately surgery.

Post-traumatic osteoarthritis: This is linked to trauma sustained at the joint surface. This may be an intra-articular fracture, a cartilage tear or anything that increases friction at the bearing surface. Post-traumatic OA occurs between 5 and 20 years after the trauma. Heavy impact sport in early life can play a part.

Inflammatory arthropathies: This group includes rheumatoid arthritis (RA) and other joint diseases characterised by a chronic nature and an inflammatory component. Autoimmunity is often involved, and the group should be considered as systemic diseases which often lead to multijoint involvement with symmetrical patterns.

In most inflammatory arthropathies the pathology is synovial, with chronic inflammation and thickening of epithelial layers leading to pain, stiffness and altered blood chemistry. Low-level joint destruction occurs over many years, and secondary osteoarthritis is eventually superimposed. Treatment aims to control or modify the inflammation to prevent progression.

Crystal arthropathies: A subgroup of inflammatory joint diseases occurs in acute episodes and causes painful joints. The most common is gout, where monosodium urate crystals enter the synovium and synovial fluid causing profound inflammation. The joint becomes hot, swollen and painful. Initial treatment is analgesia and rehydration with joint splintage. In pseudogout, similar problems are caused by calcium pyrophosphate dehydrate.

Osteomyelitis: Bone infection passes through several stages: an acute inflammatory response with soft tissue swelling, demineralisation and death of bone (sequestrum formation), then, if infection is controlled, new bone (involucrum) formation. Identifying the infecting organism by biopsy, aspirate and culture is critically important before targeted antibiotic therapy. Long courses may be needed to eradicate infection from sites with poor blood supply such as the tibia. Surgical debridement of abscesses and removal of dead bone is also an important step.

Septic arthritis: (Fig. 10.14)

This is an orthopaedic emergency and occurs by traumatic penetration of a joint or by spread from metaphyseal osteomyelitis. Articular cartilage in synovial joints is very easily damaged when a joint fills with pus. Hyaline cartilage breaks down in hours, so treatment is urgent. This means early removal of dead tissue, joint irrigation and targeted antibiotics. Without this, secondary osteoarthritis is inevitable within very few years.

In adults, the usual infecting organism in primary osteomyelitis and septic arthritis is Staphylococcus spp., although Streptococcus spp., Salmonella, Pseudomonas and other rarities occur, usually in immunocompromised patients.

Children also suffer predominantly staphylococcal infection. Widespread immunisation against Haemophilus has largely banished it as a cause of bone infection. Yeasts and fungi sometimes infect the musculoskeletal system but viruses do not, although viral influenza can cause multiple painful joint effusions and synovitis.

Plain radiology: This is the chief orthopaedic investigation. X-rays have been used for decades and doses and techniques are now refined to minimise ionising radiation. Bones are shown in great detail because of the high calcium content. The usual model is two X-rays at right angles and including nearby joints; both views must be examined for abnormality, fracture or disruption before reaching a diagnosis. Radiology of the skeleton in its loaded state can give more information, e.g. standing or flexed, and X-rays of an arthritic joint are often taken with knees and hips in a standing position.

Ultrasound: Ultrasound is widely used in orthopaedics. It gives a dynamic view of soft tissues and is good at examining liquid filled structures; bones are not seen in useful detail. Cysts, ganglia and tendons are well evaluated and a dynamic picture of a joint is valuable in motion disorders or impingement syndromes.

Magnetic resonance imaging (MRI): This modality is risk free and is increasingly used to give detail of soft tissues and three-dimensional architecture. Some examples include: nerve roots exiting the spinal cord, menisci and ligaments in the knee joint (with contrast); wrist ligaments and carpal bones can also be examined.

Computed tomography (CT): CT scans can give detail of bones down to millimetre level. Images can be reformatted into three-dimensional virtual models, e.g. for fractures or to plan complex anatomical reconstructions of acetabulum or spine.

Arthroscopy: Accurate diagnosis of a joint injury often requires internal inspection. Despite accurate history, examination and even MRI, the problem can be missed if it is transient, or only reproduced under conditions of load.

Arthroscopy is often employed for shoulder or knee, less often in the elbow and rarely in the hip. Under anaesthesia, a 5 mm arthroscope (rigid telescope with video camera) is inserted into the joint enabling inspection and, if necessary, probing with another instrument. Abnormalities can often be repaired or material removed at the same time and most procedures take less than 30 minutes so patients can go home the same day and usually recover rapidly. Arthroscopic techniques have been extended over the years to include ligament reconstruction, rotator cuff repair and cartilage repair.