Acute Compartment Syndrome of the Forearm

Impending tissue ischemia may be considered when the tissue pressure reaches between 30 mm Hg and 20 mm Hg below the diastolic blood pressure. A higher pressure is a strong indication that fasciotomy should be recommended. In a hypotensive patient, the acceptable pressure is lower. Fasciotomy should be performed in (1) normotensive patients with positive clinical findings and compartment pressures of greater than 30 mm Hg and when the duration of the increased pressure is unknown or thought to be longer than 8 hours; (2) uncooperative or unconscious patients with a compartment pressure greater than 30 mm Hg; and (3) patients with low blood pressure and a compartment pressure greater than 20 mm Hg. As a general rule, when in doubt, the compartment should be released. If it proves later to have been unnecessary, only a scar is the result. If a fasciotomy should have been done but was not, however, loss of muscle tissue and worse may result. A delay in diagnosis was the most important determining factor of poor outcome in one study. Compartment pressure should be monitored in young patients with injury to the forearm diaphysis or distal radius or in patients with significant soft tissue injury with a bleeding diathesis. Normal function was regained in 68% of patients in one study when fasciotomy was performed within 12 hours from the onset of compartment syndrome. When performing a volar fasciotomy, a volar curvilinear incision is used that allows release of the lacertus fibrosus proximally and the carpal tunnel distally. The interval between the flexor carpi ulnaris and the flexor digitorum sublimis is used for release of deep and superficial compartments. The dorsal forearm fascia is released through the interval between the extensor carpi radialis brevis and the extensor digitorum communis.

Forearm Fasciotomy and Arterial Exploration

Technique 74-2

For the volar fasciotomy, make a curvilinear incision similar to McConnell’s combined exposure of the median and ulnar nerve neurovascular bundles as described by Henry (Fig. 74-5). Make an anterior curvilinear incision medial to the biceps tendon, crossing the elbow flexion crease at an angle. Carry the incision distally into the palm to allow for a carpal tunnel release, but avoid crossing the wrist flexion crease at a right angle.

Divide the lacertus fibrosus proximally, and evacuate any hematoma.

In patients with suspected brachial artery injury, expose the brachial artery and determine whether there is a free blood flow. If the flow is unsatisfactory, remove the adventitia to expose any underlying clot, spasm, or intimal tear. Resect the adventitia if necessary, and anastomose or graft the artery.

Release the superficial volar compartment throughout its length with open scissors, freeing the fascia over the superficial compartment muscles.

Identify the flexor carpi ulnaris, and retract it with its underlying ulnar neurovascular bundle medially, and retract the flexor digitorum superficialis and median nerve laterally to expose the flexor digitorum profundus in its deep compartment. Check to see if its overlying fascia or epimysium is tight, and incise it longitudinally.

If the muscle is gray or dusky, the prognosis for recovery may be poor; however, the muscle may still be viable and should be allowed to perfuse.

Continue the dissection distally by incising the transverse carpal ligament along the ulnar border of the palmaris longus tendon and median nerve.

In cases of median nerve palsy or paresthesias, observe the median nerve along the entire zone of injury to ensure that it is not severed, contused, or entrapped between the ulnar and humeral head of the pronator teres. If it is, a partial pronator tenotomy is necessary.

In a patient with a supracondylar fracture, reduce the fracture, pin it with Kirschner wires, and control the bleeding.

Do not close the skin at this time; anticipate secondary closure later.

If the median nerve is exposed within the distal forearm, suture the distal radial-based forearm flap loosely over the nerve.

Check the dorsal compartments clinically, or repeat the pressure measurements. Usually, the volar fasciotomy decompresses the dorsal musculature sufficiently, but if involvement of the dorsal compartments is still suspected, release them also.

Make the incision distal to the lateral epicondyle between the extensor digitorum communis and extensor carpi radialis brevis, extending approximately 10 cm distally. Gently undermine the subcutaneous tissue, and release the fascia overlying the mobile wad of Henry and the extensor retinaculum.

Apply a sterile moist dressing and a long-arm splint. The elbow should not be left flexed beyond 90 degrees.

FIGURE 74-5 Incisions used in forearm in severe Volkmann contracture. A, Extensive opening of fascia of dorsum of forearm in dorsal compartment syndromes. B, Incision used for anterior forearm compartment syndromes in which skin and underlying fascia are released completely throughout. SEE TECHNIQUES 74-2, 74-4, AND 74-5.

Postoperative Care

The arm is elevated for 24 to 48 hours after surgery. If closure is not possible within 5 days, a split-thickness skin graft should be applied. Alternatively, closure of fasciotomy wounds can be accomplished gradually with progressive tension using vessel loops. The vessel loops are tightened progressively postoperatively during dressing changes. Wound closure by this method usually can be accomplished in 2 weeks (Fig. 74-6). A vacuum-assisted wound closure system may be used to assist in wound management. The splint is worn until sutures are removed or as determined by fracture care.

FIGURE 74-6 Vessel loop shoelace technique for fasciotomy closure. SEE TECHNIQUE 74-2.

Hand Fasciotomies

Technique 74-3

Make two dorsal parallel incisions through the skin overlying the second and fourth metacarpals, beginning at the level of the metacarpophalangeal joints and extending just distal to the wrist (Fig. 74-7A). Make each incision down to the musculofascial area.

Incise the fascia, and release the compression of the distended muscles by allowing them to extrude into the wound if necessary.

Identify each muscle individually to ensure that a complete release is done. Passively flex the metacarpophalangeal joints, and extend the proximal interphalangeal joints to stretch the muscles, ensuring that all are adequately released.

Release the thenar and hypothenar compartments by making additional palmar radial and palmar ulnar incisions along the glabrous and nonglabrous interval to allow for their separate decompression.

Release the carpal tunnel through a palmar midline incision.

Do not attempt to débride the interosseous muscles at this point. If the fingers are tensely swollen, and capillary refill is delayed, continue with digital fasciotomies through midlateral incisions along the radial border of the ring and small fingers and the ulnar border of the index and long fingers (Fig. 74-7B).

In general, it is prudent to release all compartments including the carpal tunnel if any of the hand compartments are involved.

Do not attempt to close the wounds at this time. They may be permitted to granulate and heal, or after the swelling has decreased, they can be closed secondarily. A vacuum-assisted wound closure system may be used to assist in wound management.

FIGURE 74-7 A, Longitudinal incisions over second and third metacarpals. B, Midaxial incision of finger. SEE TECHNIQUE 74-3.

Established Volkmann Contracture of the Forearm

If a compartment syndrome is untreated or inadequately treated, compartment pressures continue to increase until irreversible tissue ischemia occurs. Volkmann ischemic contracture is the result of several different degrees of tissue injury; however, the earliest changes usually involve the flexor digitorum profundus muscles in the middle third of the forearm (Fig. 74-8). The typical clinical picture of established Volkmann contracture includes elbow flexion, forearm pronation, wrist flexion, thumb adduction, metacarpophalangeal joint extension, and finger flexion.

FIGURE 74-8 Anatomy of Volkmann ischemia. A, “Collateral circulation” of elbow does not communicate with vessels within flexor compartment. These elbow collaterals join radial and ulnar arteries proximal to the pronator teres, the proximal guardian of the flexor compartment. B, Brachial artery and median nerve enter forearm through tight opening formed by biceps tendon insertion laterally and pronator teres muscle medially and are tightly covered by lacertus fibrosus. Proximal angulation, hematoma, or muscle swelling within this cruciate tendon-muscle portal is capable of major compression of neurovascular bundle. C, Radial artery, arising from brachial artery, passes distally superficial to pronator teres and all flexor muscles. It is not crossed by any structure along this route. Ulnar artery passes beneath pronator teres and lies in deepest portions of compartment. Median nerve usually passes between humeral and ulnar heads of fleshy pronator teres, and, emerging, it becomes compressed against firm arcuate band of flexor sublimis origin (see text).

A mild contracture, also termed localized Volkmann contracture, results from partial ischemia of the profundus mass with flexion contractures usually involving only two or three fingers. Sensory changes usually are mild or absent. Intrinsic muscle contractures and joint contractures are absent. During the early stages of a mild contracture, dynamic splinting to prevent wrist contracture, functional training, and active use of the muscles may be helpful. After 3 months, the involved muscle-tendon units can be released and lengthened. When multiple tendon units are involved, however, a muscle sliding operation is better than lengthening of multiple tendons, wrist resection, or other possible procedures. An involved pronator teres may require excision.

A moderate contracture usually involves not only the long finger flexors but also the flexor pollicis longus and possibly the wrist flexors. Median and ulnar nerve sensory changes and intrinsic minus deformities are present. In this instance, the muscle sliding operation, a careful neurolysis of the median and ulnar nerves without injuring their branches, and the excision of any fibrotic muscle mass encountered may be done. When no useful movement of the finger flexors has been retained, volar transfers of such dorsal wrist extensors as the brachioradialis and extensor carpi radialis longus and a complete release of the wrist and finger flexors may be required.

A severe contracture involves the flexors and extensors of the forearm. Fractures of the forearm bones and scars on the skin also may be present. Sensory feedback usually is impaired because the nerves are strangulated by the contracted and scarred muscles surrounding them. The preferred treatment in these instances is early excision of all necrotic muscles, combined with complete median and ulnar neurolysis to restore sensibility and possibly intrinsic function. Although one author recommended this be done no sooner than 3 months but no later than 1 year after the ischemic event, others have recommended surgical intervention within 3 weeks to prevent additional contractures from developing. Tendon transfers to restore function should be performed as a secondary procedure. These may include transfer of the brachioradialis to the flexor pollicis longus and the extensor carpi radialis longus to the flexor digitorum profundus tendons. If motors to restore finger flexion are unavailable, a free innervated muscle transfer using the gracilis muscle may be considered (see Chapter 63). In one long-term study (32 years), substantial improvement was noted with excision of fibrotic muscle, neurolysis, and tendon transfers or free gracilis transfer; however, tendon lengthening alone rarely was satisfactory. Oishi and Ezaki recommended for severe Volkmann ischemic contracture a two-stage procedure with initial muscle débridement and neurolysis followed by a free functioning gracilis transfer after return of sensation and intrinsics to the hand. Satisfactory results also have been reported using a free medial gastrocnemius myocutaneous flap for reconstruction in patients with established Volkmann contracture.

Established Intrinsic Muscle Contractures of the Hand

The proper surgical release of established intrinsic muscle contractures depends on the severity of the contractures. When the contractures are mild (Fig. 74-9), the metacarpophalangeal joints can be passively extended completely, but while they are held extended, the proximal interphalangeal joints cannot be flexed (positive intrinsic tightness test); the distal intrinsic release of Littler may be indicated (Fig. 74-10).

FIGURE 74-9 Abduction contracture of fifth finger in patient who developed fibrosis in abductor digiti quinti, probably secondary to ischemic myositis from compressive bandage.

FIGURE 74-10 Littler release of intrinsic contracture. A, Extensor aponeurosis at level of metacarpophalangeal joint consists of long extensor tendon, transverse fibers (which flex metacarpophalangeal joint), and oblique fibers (which extend interphalangeal joint). Crosshatched part is resected from each side of hood. B, Appearance of aponeurosis after release. SEE TECHNIQUE 74-6.

In contractures that are more severe, the interosseous muscles are viable but contracted and the intrinsic tightness test is positive. Active spreading of the fingers may be possible. In these instances, the contracted muscles may be released from the metacarpal shafts by a muscle sliding operation (Fig. 74-11A).

FIGURE 74-11 A, Method of stripping and advancing interosseous muscles to slacken them, allowing proximal finger joints to extend and distal two to flex. Interosseous muscles of two clefts have been stripped. Stripping of interossei is done only when muscles still retain considerable function. Nerve supply should be spared. B, Complete intrinsic tenotomy for severe intrinsic contractures in which nonfunctioning interosseous muscle remains.

In the most severe contractures, the intrinsic muscles not only may be contracted but also necrotic and fibrosed, so any useful muscle excursion is absent. In these instances, the tendon of each muscle must be divided to release the contractures (Fig. 74-11B). Other procedures, such as capsulotomies and tendon transfers, also may be necessary.

Adducted Thumb

Only complete loss of the thumb causes more disability in the hand than a fixed severe adduction of the thumb (web contracture). The thumb is the only digit with the ability to bring its terminal sensory pad over the entire surface of any chosen finger or over the distal palmar eminence. The saddle-like first carpometacarpal joint provides the circumductive movement of the thumb necessary for pinch or grasp. The intrinsic muscles of the thumb and the extrinsic flexors and extensors all are important in the balanced control required in performing these functions effectively. The short abductor muscle positions and stabilizes the thumb metacarpal for pinch; the adductor muscle supplies power for pinch by acting on the proximal phalanx; the long extrinsic flexor positions the distal phalanx in varying degrees of flexion and consequently controls the type of pinch, whether it be fingernail-to-fingernail opposition or pulp-to-pulp opposition with another digit. The thumb web must be supple if these important movements of the thumb are to be possible. Any contracture of the thumb web causes limited opposition of varying degrees. In severe contracture, the thumb is in a position of adduction and external rotation.

The thumb web consists of skin, subcutaneous tissue, muscle, fascia, and joint capsule. Contracture of any one of these tissues can cause a secondary contracture of the others; rarely is there contracture of only one. Scarring of the skin, burns, infection, crush injuries, congenital webbing, paralysis, Dupuytren contracture, and faulty immobilization for some injuries are causes.

The proper treatment of a contracted web is determined by which structures of the web are involved; little is accomplished by releasing the skin alone when deeper structures, such as muscle, fascia, or joint capsule, also are contracted. When the skin alone is contracted from a hypertrophic scar after a surgical incision or a laceration along the border of the web, it sometimes can be released by a Z-plasty or a local flap.

Crushing injuries, infections, or deep burns result in extensive fibrosis within the thumb web that cannot be treated by release of the skin alone; rather, the scarred components of the contracted skin, muscle, fascia, and capsule must be excised with care to avoid damaging the radial artery near the carpometacarpal joint. This excision produces a deep fissure that must be filled with skin and subcutaneous fat to provide an elastic functioning web. Usually this can be accomplished by dorsal rotation or a sliding flap with supplemental skin grafting (Figs. 74-12 and 74-13). If adjacent dorsal skin is unsuitable for transfer, a cross arm flap may be considered. The cross arm flap is fashioned as a double triangle, one on the dorsal surface and one on the volar surface of the web, to eliminate any line of scar paralleling the border of the web. The first and second metacarpals are fixed in the desired position with Kirschner wires. When motion in the carpometacarpal joint can be restored, any necessary tendon transfers for apposition can be done later, but if motion cannot be restored, the carpometacarpal joint must be arthrodesed to maintain the new position of the thumb permanently.

FIGURE 74-12 One method of releasing dorsal skin of adducted thumb (see text) (Brand). A, Skin incision. B, Skin grafting covers defect after release has been accomplished by undermining dissection.

FIGURE 74-13 Cross arm flap coverage of deepened thumb web. A, Web space deepening after skin division and muscle recession. B, Position of hand with triangular distal flap (b) sutured into dorsal thumb web defect. Outline of proximal triangular flap (a) that will be used for palmar web coverage. C, Web space reconstruction after transfer of palmar flap at second-stage operation 3 weeks later.

Paralysis of the muscles of apposition can result in secondary contracture of the skin and joint capsule and in contracture of the thumb web, requiring release by a Z-plasty or by a local flap and a skin graft as described by Brand and Milford (see Fig. 74-13). Contracted fascia and bands of muscle must be released, and capsulotomy of the carpometacarpal joint must be done at the same time.

Occasionally, a useless index finger may provide a filleted pedicle with which a satisfactory thumb web can be constructed in one stage. This procedure not only widens the web in that the index metacarpal is excised but also provides skin that can be repositioned over a nearby defect or scar (see discussion of filleted graft in Chapter 65).