Practical Plastic Surgery

482 Practical Plastic Surgery

Table 80.1. Hand infections and the empiric antibiotics of choice

80Note: emerging bacterial resistance to cephalosporins may require the use of a secondor third-generation agent.

The most common infections and their management are discussed below:

Cellulitis

The dorsum of the fingers are most commonly affected. Streptoccoci and S. aureus are the likely offending organisms. Conservative therapy with oral antibiotics and elevation is often sufficient. However, if there are signs and symptoms of systemic infection (fevers, chills, increased WBC count, etc), ascending lymphangitis, lymphadenitis, or failure of oral antibiotics, the patient should be admitted for IV antibiotics and hand splinting in the intrinsic plus position.

Bites

Animal and human bites account for about a third of all hand infections. They not only can cause tissue damage but also can lead to serious infections if not treated properly. Human bites often cause infection due to the virulent microaerophilic Streptococci, S. aureus, and Eikenella corredens found in the human mouth.

Human Bites

Human bite wounds can be devastating. The human mouth contains mixed flora that can synergistically infect and destroy soft tissues, tendons, joints, and bones. For instance, a clenched fist that strikes a person’s mouth can result in a

Table 80.2. Principles of hand infection management

•Incision and drainage of pus

•Debridement of necrotic tissue

•Antibiotics-first empiric (usually a two-drug regimen) then targeted based on cultures

•Tetanus prophylaxis when indicated

•RICE (rest, immobilization, cold, and elevation)

•Early hand therapy

tooth penetrating the extensor tendon, metacarpal head or joint space. In such cases it is important to examine the hand with the fist in the clenched position. Early infections may present with nothing more than minimal swelling and erythema. These can often be treated as an outpatient, with exploration, debridement, irrigation and oral antibiotics. Advanced infections, however, can be severe with purulence and accompanying lymphangitis or lymphadinitis. Untreated, irreversable damage to vital structures can occur. At the first sign of severe infection, the patient must be hospitalized and the infection treated aggressively with debridement, drainage, irrigation, antibiotics, immobilization, and elevation. Human bite wounds to the hand should not be closed, but rather left open to heal secondarily. The wound should be evaluated on a daily basis to ensure that it is healing.

Dog and Cat Bites

Dog bites account for 90% of all animal bites. Dog bite wounds are often lacerations or avulsions of soft tissue, whereas cat bites are usually deep puncture wounds.

Not all bites become infected. Animal bites are less likely to progress to a clinical 80 infection than human bites. An infected animal bite presents as rapidly progressing cellulitis and swelling with drainage from the bite wounds. The organisms frequently

seen in dog bites are S. aureus, S. viridans, Pasturella multocida and Bacteroides species. Cat bites have similar organisms with a large number of Pasturella multocida often present. Treatment is similar to human bites. Antibiotic coverage against Pasturella (penicillin) should be included.

Paronychia

A paronychia is a soft tissue infection adjacent to the nail. Bacteria enter the surrounding tissue through the nail fold, usually after the patient pulls or bites a hang nail, or secondary to a foreign body at the site (such as a splinter). Consequently, the infection will often contain oral flora in addition to S. aureus. If discovered early, it can be treated with warm daily soaks, elevation and oral antibiotics. After the first 24 hours of infection, pus may develop under the nail fold. In such cases, treatment consists of elevating the nail fold off the nail to allow it to drain. Paronychia that fail this more conservative approach may require removal of the nail plate for adequate drainage to occur.

Chronic paronychia occur in the immunocompromised; Candida albicans is the most common organims involved. It usually involves nail bed destruction with the resulting nail plate fragments acting as a foreign body. This condition requires X-rays to rule out distal phalanx involvement. Treatment consists of excision of the proximal nail fold with healing by secondary intention or removal of the nail and topical antifungal therapy. Tissue specimens should be sent for culture and pathology to rule out an exotic infection or occult carcinoma/melanoma.

Eponychia

Eponychia is a soft tissue infection at the base of nail. It is usually caused by an infected hangnail or extension of an untreated paronychia. Conservative treatment is similar to that of a paronychia. More advanced infections may require paired incisions at the base of the nail. These are perpindicular incisions made at each lower corner of the nail.

Felon

A felon is an infection of the distal finger tip pulp, usually due to S. aureus. It can develop after a puncture wound or as the result of a proximally-extending paronychia. Patients often complain of dependent pain due to the pressure build up of fluid in the confined space of the pulp. Because of the fibrous septa in the volar pad, a felon is a closed space infection that must be incised and drained. If the infection has not pointed, the incision should be made over the site of greatest tenderness. Antibiotics and elevation of the hand are also important. When not treated adequately, a felon can spread into the phalanx, adjacent joint space, or flexor tendon sheath. X-rays should be performed to evaluate for the presence of a foreign body.

Deep Space Infections

The deep spaces in the hand include the thenar space, midpalmar space, web spaces, and subtendinous (Parona’s) space. Deep space infections usually follow a deep puncture wound, and S. aureus is the most commonly cultured organism. They require incision and drainage, antibiotics, splinting and elevation. Care must

80be taken not to injure the nearby neurovascular structures. These infections are often contained in a single space, but if neglected and allowed to spread they can form a “horse shoe abscess,” involving several deep hand spaces.

Infectious Tenosynovitis

Infections of the tendon sheath are most commonly due to Gram-positive, aerobic bacteria such as S. aureus. Human bites predispose to anaerobic organisms as well. Animal bites carry the additional risk of Pasteurella multocida infection. Gonococcal flexor tenosynovitis is due to hematogenous spread of disseminated gonorrhea.

Diagnosis

Dr. Kanavel described the cardinal signs of acute flexor tenosynovitis (Kanavel’s signs):

1.Pain with passive finger extension

2.Tenderness over the entire length of the flexor sheath

3.Finger held in the semiflexed position

4.Swelling of the finger

Treatment

Acute flexor tenosynovitis is a serious condition that requires immediate treatment. In cases of nonsuppurative tenosynovitis, 24 hours of broad spectrum antibiotics, splinting and elevation can be tried. If the patient does not improve, tendon sheath irrigation is indicated. Suppurative tenosynovitis is a surgical emergency, and tendon sheath irrigation is the mainstay of treatment. A proximal incision is made at the level of the distal palmar crease proximal to the A1 pulley. A distal incision is made over the DIP joint distal to the A5 pulley. The sheath is exposed, opened, and vigorously irrigated with antibiotic solution. Postoperatively, a catheter can be left in place distally and proximally to allow irrigation of the sheath. Intravenous antibiotics are also used, although the irrigation of the sheath is primary treatment. Patients are usually hospitalized for 2-3 days.

Outcome and Complications

Two to three days following surgery, active motion exercises are initiated. Complete functional recovery usually occurs within 1-2 weeks. Complications of flexor tenonsynovitis include tendon necrosis, rupture, or adhesions, joint complications, osteomyelitis, deep space abscess and even amputation.

Pearls and Pitfalls

When performing any incision and drainage procedure, the location of the incision must be carefully considered to optimize the function and aesthetics once the wound heals. For bite wounds, the site of penetration will often lead directly to the location of the purulence, and the choice of incision site becomes obvious. For paronychia and eponychia, the space between the nail plate and overlying skin fold is usually the site of drainage. In a deep space infection, make the incision over the most fluctuant, inflamed area. The same is true for a felon that has pointed. Otherwise, make a mid-lateral incision deep into the volar pulp to disrupt the septa. Avoid fish-mouth incisions since these can result in a fingertip deformity

after healing. For suppurative tenosynovitis, a mid-lateral incision is an excellent 80 choice, since a Bunnel-type incision that breaks down can expose the underlying flexor tendon sheath.

Suggested Reading

1.Arons MS, Fernando L, Polayes IM. Pasteurella multocida—the major cause of hand infections following domestic animal bites. J Hand Surg 1982; 7A:47.

2.Brook I. Paronychia: A mixed infection. Microbiology and management. J Hand Surg 1993; 18:358.

3.Dellinger EP, Wertz MJ, Miller SD et al. Hand infections. Bacteriology and treatment: A prospective study. Arch Surg 1988; 123(6):745.

4.Goldstein EJ. Current concepts on animal bites: Bacteriology and therapy. Curr Clin Top Infect Dis 1999; 19:99.

5.Hausman MR, Lisser SP. Hand infections. Orthop Clin North Am 1992; 23:171.

6.Moran GJ, Talan DA. Hand infections. Emerg Med Clin North Am 1993; 11:601.

impaired venous return, increased capillary permeability and vasodilation, all of which cause greater fluid accumulation and serve to increase the pressure even further.

The tissues most sensitive to the resulting ischemia are nerve and muscle. Greater than 6-8 hours of ischemia will cause irreversible nerve and muscle damage. The deeper compartment muscles (such as flexor digitorum profundus) are usually affected first, and the central portions of the muscle belly are more susceptible due to poor collateral circulation.

Clinical Diagnosis

The diagnosis of compartment syndrome is clinical. Measurement of compartment pressures should be used only as an adjunctive tool. The signs and symptoms are usually progressive and include the following:

•A swollen, tense compartment

•Digits in MP extension and PIP flexion

•Pain out of proportion to the underlying injury

•Pain with passive stretching of the involved muscles

•Paresthesias in the distribution of the involved nerves

•Impaired two-point discrimination test

•Motor weakness in the distribution of the involved nerves/muscles

•Intact pulses or dopplerable arterial signals

Compartment Pressure Measurements

As stated above, compartment syndrome is a clinical diagnosis and pressure measurements only aid in confirming the diagnosis. In the uncooperative or obtunded patient however, an accurate exam is not possible, and objective pressure

determination can be of value if there is a high index of suspicion. The normal capillary perfusion pressure ranges from 20-25 mm Hg. Several techniques are available for measuring compartment pressure; however they differ on the threshold pressure used to make the diagnosis of compartment syndrome.

Whitesides’ method describes the use of needle manometery using readily available supplies. This technique considers a pressure within 20 mm Hg of the diastolic pressure as its threshold. A modification of this method can be performed using a standard arterial line connected to an 18 gauge needle inserted into the compartment.

The Matsen technique involves continuous monitoring of the compartment pressure for up to 3 days. It is similar to Whitesides’ technique. An absolute pressure threshold of 45 mm Hg is considered positive.

Finally, the Murbarak method directly measures compartment pressure using a wick (slit) catheter. There are a number of hand-held devices available that rely on this technique. Any pressure above 30 mm Hg is considered highly suggestive of compartment syndrome.

In the forearm, the needle should be inserted in the middle of each compart-

81ment, which corresponds more or less to the middle third of the forearm. In the hand, the pressure should be measured in the four dorsal and three volar interosseous compartments, as well as in the thenar and hypothenar compartments on the palmar surface. In the wrist, pressure should be measured in the carpal tunnel.

Management

Compartment syndrome is a surgical emergency. Without timely compartment release, irreversible damage will ensue. Most studies indicated that the fasciotomy should be performed within 12 hours of compartment syndrome onset. It is controversial whether to perform a fasciotomy more than 48 hours after injury. If the cause of the compartment syndrome is due to excessive external pressure, this should be immediately relieved. All dressings and cast material should be removed since this alone can significantly reduce compartment pressure and occasionally eliminate the need for surgical decompression.

Operative Treatment

The surgical release of the compartments is termed a fasciotomy. Occasionally a prophylactic fasciotomy is performed following revascularization of a limb that has been ischemic for over 4 hours. Skin incisions after fasciotomy are generally left open. They may be loosely approximated to cover any exposed nerves. The incisions can be closed several days later or skin-grafted if direct closure is not possible.

Arm

Two separate incisions are required. The flexor compartment is decompressed via an incision extending from the acromion along a line that lies just medial to the lateral bicipital sulcus. The extensor compartment is released using an incision that extends proximally from the olecranon along the lateral side of the arm over triceps. Alternatively, both compartments can be released through a single incision extending from the shoulder to the elbow crease along a line overlying the medial intermuscular septum.

Figure 81.1. The S-shaped fasciotomy incision for release of the volar compartment and mobile wad of the forearm. The incision extends from proximal to the elbow crease and into the palm, releasing the carpal tunnel along with the forearm.

Forearm and Wrist

Release of the flexor compartment and the mobile wad should be performed

first since often this will reduce the elevated pressure in the dorsal compartment. 81 An S-shaped skin incision is made, extending from proximal to the elbow crease

and into the palm (Fig. 81.1). Thus, the carpal tunnel is released along with the volar compartment. After the skin and subcutaneous tissue have been incised, the deeper fascia (including the transverse carpal ligament) is incised and the muscles are mobilized. The median nerve is identified and full release of any nerve compression is performed along its entire course. If there is suspicion of ulnar or radial nerve compromise, these nerves should also be decompressed.

If the dorsal compartment still has elevated pressures after volar release, a dorsal fasciotomy incision is made. It begins from a point 2 cm lateral and distal to the lateral epicondyle and extends about 10 cm towards the center of the wrist.

Hand

Decompression of all of the hand compartments requires multiple volar and dorsal incisions. The dorsal and palmar interosseus compartments are approached using two dorsal incisions over the second and fourth metacarpals (Fig. 81.2). The thenar and hypothenar compartments are accessed through a longitudinal incision along the radial side of the first metacarpal, and the ulnar side of the fifth metacarpal, respectively (Fig. 81.2). The carpal tunnel is released using either the standard open approach, or with an extended incision that can also allow Guyon’s canal to be released (for ulnar nerve decompression). Access to the adductor compartment can be gained through the carpal tunnel release.

Postoperative Considerations

In the immediate postoperative period, urine myoglobin levels should be monitored since elevated levels can produce acute renal failure. Myoglobinuria peaks several hours after circulation is restored. Prophylaxis and treatment consist of alkalinizing the urine and keeping the patient well-hydrated. A urine output of at least 1-2 ml/kg/ hr should be maintained. Serum creatinine phosphokinase (CPK) levels should also be followed since extremely high CPK levels are also a risk factor for renal failure.

81

Figure 81.2. Fasciotomy incisions over the second and fourth metacarpals for releasing the dorsal and palmar interosseus compartments. Longitudinal fasciotomy incisions along the radial side of the first metacarpal and the ulnar side of the fifth metacarpal for release of the thenar and hypothenar compartments, respectively. The carpal tunnel is released via an extended incision which also allows access to Guyon’s canal and the adductor compartment.

The arm is dressed in a bulky dressing and kept elevated postoperatively. The patient is brought back to the operating room after 3-5 days for wound inspection and fasciotomy closure. If direct closure is not possible, split-thickness skin grafts are used to cover the defect. This can be done immediately or within 1-2 weeks. Active and passive hand motion exercises should be initiated as soon as possible to help limit stiffness and contractures.

Complications

Unrecognized or undertreated compartment syndrome is likely to result in one or more complications. Even those cases that are recognized and treated in a timely fashion can be complicated by one of the following:

•Wound complications such as infection, dehiscence, and hypertrophic scarring

•Intrinsic hand contracture secondary to necrosis and fibrosis of intrinsic hand muscles

•Volkman’s contracture of the forearm flexor muscles

•Scar contracture across the elbow or wrist leading to impaired joint motion

•Hand or arm dysfunction secondary to permanent muscle injury

•Renal failure secondary to rhabdomyolysis

•Neurologic sequelae

•Sensory nerve deficits

Pearls and Pitfalls

The diagnosis of compartment syndrome is challenging and requires a high index of suspicion. The clinical exam, underlying mechanism, and pressure measurements

1.Botte MJ, Gelberman RH. Acute compartment syndrome of the forearm. Hand Clin 1998; 14:391.

2.Gellman H, Buch K. Acute compartment syndrome of the arm. Hand Clin 1998; 14:385.

3.Ortiz Jr JA, Berger RA. Compartment syndrome of the hand and wrist. Hand Clin 1998; 14:405.

4.Serokhan AJ, Eaton RG. Volkmann’s ischemia. J Hand Surg [Am] 1983; 8:806.

5.Whitesides TE, Haney TC et al. Tissue pressure measurements as a determinant for the need of fasciotomy. Clin Orthop 1975; 113:43.