Hội chứng mãn tính ngăn Exertional pptx

Each compart-ment contains one major nerve, and two compartments anterior and deep posterior house major blood vessels, which may be affected by CECS.. Compartment ischemia is considered

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Michael J Fraipont, MD, and Gregory J Adamson, MD

Abstract

Compartment syndrome is defined as

increased pressure within a closed

fibro-osseous space, causing reduced

blood flow and tissue perfusion in

that space, leading to ischemic pain

and possible damage to the tissues of

the compartment Compartment

syn-drome may be either chronic or acute

Chronic compartment syndrome is

often recurrent and is associated with

repetitive exertion It is typically seen

in athletes whose exercise level

ele-vates the intramuscular pressure to

a point that the tissues within the

af-fected compartment become tight and

painful, thus preventing further

ac-tivity The pain disappears quickly

after rest, and there are usually no

permanent sequelae in the affected

tissue In 1962, French and Price1

doc-umented elevated compartment

pres-sures as the cause of chronic

exertion-al compartment syndrome (CECS) of

the tibia Previously, in 1956, Mavor2

had successfully treated a CECS by

widening the fascia of the anterior

compartment of the tibia The

ante-rior and lateral compartments of the

leg are most commonly involved in CECS, but it has been described in all compartments of the leg, shoulder, upper arm, forearm, hand, gluteus, thigh, and foot

In contradistinction, acute com-partment syndromes, whether in-duced by trauma or repeated exer-tion, are commonly progressive and require urgent attention to avoid ir-reversible damage to the tissues of the affected compartment Patients with acute compartment syndrome pre-sent with severe pain that is exacer-bated by passive stretch of the muscles and does not resolve spon-taneously with rest Development of paresthesia and pallor can be fol-lowed by the loss of pulse in the dis-tal extremity The typical presentation

of an acute compartment syndrome most often occurs after a high-energy trauma with or without fracture or reperfusion of an ischemic limb In an exercise-induced acute compartment syndrome, symptoms may not

devel-op until 24 to 48 hours after the pre-cipitating event The syndrome has

been reported in the hand, forearm, leg, thigh, gluteus, and foot In the rare untreated case, an acute compart-ment syndrome may result in myo-necrosis, causing release of myoglo-bin into the vascular circulation, which can lead to renal failure Treat-ment of myonecrosis consists of prompt hydration, restoration of

flu-id deficits, and concomitant diuresis (maintained at 100 to 200 mL/h).3

Anatomy

The three areas most commonly af-fected by CECS are the lower leg, thigh, and forearm The lower leg consists of four compartments: ante-rior, lateral, superficial posteante-rior, and deep posterior (Fig 1) Each compart-ment contains one major nerve, and two compartments (anterior and deep posterior) house major blood vessels, which may be affected by CECS The anterior compartment contains the anterior tibial artery and the deep peroneal nerve The lateral compartment contains the superficial peroneal nerve The superficial pos-terior compartment contains the sural

Dr Fraipont is Assistant Clinical Professor, Department of Orthopaedic Surgery, University

of Southern California, Pasadena, CA Dr Adamson is Associate Clinical Professor, Depart-ment of Orthopaedic Surgery, University of Southern California.

Chronic exertional compartment syndrome is an often overlooked and uncommon

cause of pain in the extremities of individuals who engage in repetitive physical

ac-tivity A thorough history, a careful physical examination, and compartment

pres-sure testing are essential to establish the diagnosis Catheter meapres-surements can

pro-vide useful information on baseline resting compartment pressures as well as

compartment pressures after exercise or trauma Patients with chronic exertional

compartment syndrome usually do not respond to nonsurgical therapy other than

completely ceasing the activities that cause the symptoms Surgical intervention

en-tails fasciotomies of the involved compartments Although obtaining accurate

com-partment pressure measurements can be difficult and fascial releases must be done

carefully, patients typically have satisfactory functional results and are able to

re-turn to their usual physical activities after fasciotomy.

J Am Acad Orthop Surg 2003;11:268-276

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nerve The deep posterior

compart-ment contains the posterior tibial

nerve and both the posterior tibial

and peroneal arteries and veins

The thigh consists of three

compart-ments that can be affected by CECS:

anterior, medial, and posterior (Fig

2) The anterior compartment contains

the femoral nerve The medial

com-partment contains the obturator nerve

and both the femoral and femoral

pro-fundus arteries The posterior

com-partment contains the sciatic nerve

The forearm consists of three

com-partments: volar (superficial and deep)

and dorsal, and the mobile wad (Fig

3) The volar compartment consists of

the six muscles responsible for

ion, pronation, and supination:

flex-or carpi radialis, flexflex-or pollicis

lon-gus, palmaris lonlon-gus, flexor digitorum

superficialis, flexor carpi ulnaris, and

flexor digitorum profundus This

com-partment also contains the median and

ulnar nerves along with the radial,

ul-nar, and anterior interosseous

arter-ies The dorsal compartment contains

the extensor pollicis brevis, extensor

digitorum communis, and extensor carpi ulnaris muscles, as well as the posterior interosseous nerve and ar-tery and perforators off the anterior interosseous artery The mobile wad consists of three muscles: the brachio-radialis, extensor carpi radialis lon-gus, and extensor carpi radialis brevis

Pathophysiology

During strenuous exercise, muscle fi-bers can swell to up to 20 times their resting size, leading to a 20% increase

in the muscle volume and weight.4 In-creased perfusing blood volume, muscle hypertrophy, and interstitial fluid volume within a nonexpanding compartment increase pressure in ac-cordance with Laplace’s law (a cap-illary membrane subjected to internal and external pressure reaches an equilibrium based on those forces) The blood flow through muscles is chiefly regulated by the resistance of the arteriole, which depends on the tension in the vascular wall The in-crease in intramuscular pressure causes a decrease in arteriolar blood flow Even though the circulation may not be totally arrested, venous return

is markedly reduced and some cap-illaries may become occluded When the blood flow is insufficient

to meet the requirements of the mus-cle, the patient experiences pain with continued activity The symptoms of CECS, which result from this is-chemia, are caused by inadequate tis-sue oxygenation from the decreased venous return and insufficient perfu-sion of muscle tissue Because mus-cles have blood flow only during the

Figure 1 Cross section of the lower left leg.

Figure 2 Cross section of the left thigh, 10 to 15 cm inferior to the inguinal ligament Note the intermuscular fascial septa.

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relaxation phase of exercise, increased

intracompartmental pressures during

the relaxation phase are thought to

have the greatest effect on muscle

is-chemia The most critical

intracom-partmental pressures are those

present when the muscle is not in a

contractile state During this phase,

the balance between intramuscular

compartment pressure and the

mi-crovascular pressure determines the

adequacy of perfusion and, hence, the

oxygenation of the muscle These

val-ues are best reflected by measuring

postexercise pressure The patient

will continue to experience pain in the

affected extremity after exercise

un-til the total intramuscular pressure

decreases to a level at which the blood

flow can again meet the muscle’s

re-quirements

Of patients with CECS involving

the legs, 39% to 46% have fascial

de-fects over the anterolateral lower leg

compared with asymptomatic

indi-viduals, who have <5% incidence.4,5

These fascial hernias or defects are

usually 1 to 2 cm2in size and occur

near the intermuscular septum

be-tween the anterior and lateral

com-partments, often at the exit of the

su-perficial peroneal nerve The fascial hernia is approximately at the junc-tion of the middle and distal thirds

of the leg The superficial peroneal nerve can be compressed by either the edge of the fascial defect itself or the muscle bulging through the defect At rest, no palpable abnormality may be apparent, but with exercise, local ten-derness and swelling may occur Oc-casionally Tinel’s sign may be found

at the site of the hernia

It is not clear why patients with CECS have increased total intramus-cular pressure at rest and higher than normal intramuscular pressure with exercise compared with normal indi-viduals It is unlikely that a limited osseofascial expansion can be the sole explanation of this increase because, after fasciotomy, the total intramus-cular pressure at rest usually remains higher than that in normal individ-uals In addition, while fascial

herni-as are a contributing anatomic find-ing, fascial hernias are not present in all patients with CECS Arteriole reg-ulation also may be a factor;

howev-er, it is likely that a combination of anatomic limitations contributes to the presence and severity of CECS.6

Evaluation History

During physical exertion, a patient with CECS often notices pain that ini-tially begins as a dull ache If it is ig-nored and the patient continues to train, the pain increases to the point that the activity must be stopped The onset and degree of the pain often be-come both predictable and reproduc-ible because the pain begins at about the same time during the exercise ac-tivity The pain typically is well local-ized to the entire affected compart-ment

Patients experience a feeling of fullness or a cramplike sensation in the affected compartment when they attempt to exercise They also may complain of transient numbness, tin-gling, or weakness in the motor and sensory distributions of nerves

with-in the with-involved compartments In some cases, patients may have had a recent increase in training time or in-tensity that now takes them over their threshold level for generating symp-toms Rest usually relieves the pain, but it takes some time for complete relief to occur, especially as the CECS becomes more severe Patients typi-cally will not have persistent pain the following day unless they exercise again Generally, they have no

histo-ry of trauma, and if they return to their sport after discontinuing it for some time, the symptoms typically recur Most patients present with bi-lateral symptoms.7

Patients with CECS of the fore-arm complain of a feeling of firm-ness or cramping associated with weakness in the hands and wrists during vigorous athletic or repeti-tive grasping activities In addition, they may experience numbness and tingling These symptoms can man-ifest in the thenar, interosseous, or hypothenar regions as well as in the forearm Symptoms resolve quickly when the activity is discontinued but recur with resumption of the ac-tivity

Figure 3 Cross section of the middle of the left forearm distal to the level of the pronator

teres insertion.

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Physical Examination

Results of the physical

examina-tion of the lower extremity at rest are

usually normal However, Rowdon et

al8showed that athletes with CECS

demonstrated a contradictory

elec-tromyographic finding: decreased

postexercise potentiation of the

pe-roneal motor amplitude and mild

im-pairment in vibratory sensation

Di-rect inspection and circumference

measurements are typically normal;

however, muscle atrophy may be

found if the condition is unilateral

Results of physical examination of the

extremity after it has been provoked

by exercise may reveal tenderness

and increased tension in the involved

compartment In addition, there may

be an associated decreased sensation

or tingling in the distal region

In the upper extremity, results of

physical examination usually reveal

neither signs of nerve entrapment (eg,

a Tinel sign at the wrist or elbow) nor

abnormal two-point discrimination

Results of the neurodiagnostic

eval-uation, including nerve-conduction

studies and electromyographs of the

ulnar and median nerves, also should

be normal, although Kutz et al9

re-ported slowed median nerve

conduc-tion in one case While muscle

ten-derness may be noted, symmetrically

functioning muscles in the hands and

forearms are usually found

Differential Diagnosis

A number of different conditions

may overlap with the diagnosis of

CECS (Table 1) When the patient

his-tory, physical examination results,

and pressure measurements are not

diagnostic for CECS, consideration

should be given to further imaging,

neurophysiologic testing, and/or

lab-oratory studies

Testing

Equipment and Criteria

Patients with CECS demonstrate

increased intracompartmental

pres-sures in the affected extremity at rest and during and after exercise Mea-suring intracompartmental pressures during exercise is difficult and im-practical; resting and postexercise measurements have been shown to be the best method of confirming the di-agnosis of CECS.4,5,10-12 The type of exercise used during measurement taking can vary, but it must be suf-ficiently provocative to induce symp-toms The following different com-partment measurement methods show equal effectiveness, assuming correct use: slit catheter,13 microtip pressure method,14 wick catheter,15

microcapillary infusion,5and needle manometer.16

Many authors use the criteria of Pedowitz et al10to evaluate patients These criteria are appropriate for eval-uation of both the upper and lower extremities: a resting pressure mea-surement ≥15 mm Hg, and/or a measurement taken 1 minute after ex-ercise≥30 mm Hg, and/or a measure-ment taken 5 minutes after exercise

≥20 mm Hg The criteria of Whitesides and Heckman17for acute compartment syndrome have been applied to CECS Compartment ischemia is considered

to occur when a compartment

pres-Table 1 Differential Diagnosis for Chronic Exertional Compartment Syndrome

Diagnosis Findings Confirmatory Studies Stress fracture Localized tenderness

directly over the tibia;

pain with torsional or bending stress

Plain radiograph, bone scan, MRI

Medial tibial stress syndrome (periostitis at the muscular attachment site along the

posteromedial tibia)

Manual resistance to active plantarflexion and inversion leading to pain along the distal

posteromedial aspect of the tibia; localized to diffuse tibial tenderness

Bone scan, MRI

Chronic regional pain syndrome (reflex sympathetic dystrophy)

Allodynia and trophic skin changes

Triple-phase bone scan, thermography, sympathetic block Tenosynovitis of the

ankle dorsiflexors or the posterior tibialis tendon

Tenderness along the extent of the tendon aggravated by flexion and extension maneuvers

MRI

Peripheral nerve entrapment syndromes

Tingling or numbness associated with a specific location (Tinel’s sign)

EMG, nerve conduction study Venous stasis disease Trophic skin changes Duplex ultrasound Deep vein thrombosis Palpable cords or pain

with plantarflexion; calf swelling

Duplex ultrasound, venogram

Radiculopathy Sensory losses, weakness EMG, central nervous

system evaluation Arterial vascular disease Pain, paresthesias, and

coolness with activities;

claudication

Ankle-brachial index

Popliteal artery entrapment syndrome

Pain and coolness;

paradoxical claudication

Arteriogram

EMG = electromyogram; MRI = magnetic resonance imaging

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sure increases to 20 mm Hg below the

diastolic pressure

Measurement Limitations

Factors that can affect the

accura-cy of pressure measurements include

proper use of the equipment, correct

anatomic placement of the catheter

tip, depth of needle insertion,

posi-tion of the extremity during pressure

measurement, and the contractile

force of the muscle This process can

be especially difficult to control and

interpret in the clinical setting

There-fore, care must be taken to place the

limb in a relaxed and consistent

po-sition for accurate, reproducible

mea-surements

Although the measurement of

in-tracompartmental pressures of the

anterior compartment of the leg is

rel-atively simple, the same cannot be

said for the deep posterior

compart-ment or for the so-called fifth

com-partment, the tibialis posterior

mus-cle When measuring deep posterior

compartment and tibialis posterior

muscle pressures, the exact location

of the tip of the catheter may vary

Schepsis et al18described a method

of placing the catheter medially,

par-allel to the posterior surface of the

tib-ia at the junction of the middle and

distal thirds of the leg, into the flexor

digitorum longus muscle Wiley et

al19proposed using ultrasound as a

guide for catheter placement into the

deep posterior compartment Mollica

and Duyshart20advocated placing

in-tracompartmental pressure

measure-ment apparatus in the medial foot

compartment Upper extremity

cath-eter placement is dcath-etermined by the

affected compartment.21,22

Other Testing Modalities

Alternative methods of testing for

elevated compartment pressures are

being considered, especially because

of the difficulty in measuring the deep

compartment pressures Mohler et al23

found that patients with CECS of the

anterior compartment had greater

deoxygenation of the muscle during

Figure 4 The single-incision or perifibular approach allows access to all four compartments

through a lateral incision A, The skin incision is made in line with and directly over the fibula B, Release of the lateral compartment (2) can be done directly after identification of

the intermuscular septum Care must be taken to preserve the superficial peroneal nerve,

and the fasciotomy is done 1 cm posterior to the intermuscular septum C, If the anterior

compartment (1) needs to be released, the skin is retracted anteriorly and the fasciotomy is

done 1 cm anterior to the intermuscular septum D, For the fasciotomy of the superficial pos-terior compartment (3), the skin is retracted pospos-teriorly for exposure E, For fasciotomy of

the deep posterior compartment (4), the lateral and superficial posterior compartments are retracted and the compartment is reached by following the interosseous membrane from the posterior aspect of the fibula (Adapted with permission from Rorabeck CH: A practical

ap-proach to compartment syndromes: III Management Instr Course Lect 1983;32:102-113.)

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exercise and delayed reoxygenation

of the muscle after exercise compared

with patients who did not have CECS,

as measured by infrared

spectrosco-py A more promising and practical

measurement of elevated pressure is

by magnetic resonance imaging, which

can be used in diagnosing CECS.24The

affected compartment shows an

in-crease in T2-weighted signal

intensi-ty during exercise Although the

as-sistance of an experienced radiologist

in reviewing these subtle findings can

be helpful, the intracompartmental

sig-nal intensity can be normalized with

the signal intensity from surrounding

tissue not affected by CECS.24Bone

scan technology using thallium Tl 201

single-photon emission computed

to-mography (SPECT) has been shown

to localize an ischemic compartment.25

Management

CECS occurs when athletes perform

an activity above their threshold

lev-el Therefore, nonsurgical treatment

of CECS can be successful only when

the patient gives up the activity or the

activity level that causes the

symp-toms However, it is not unreasonable

to offer a treatment plan that includes

stopping the activities that provoke

the symptoms while introducing a

different program of appropriate

con-ditioning Nevertheless, because most

patients with CECS who seek

med-ical attention are unwilling to

mod-ify their exercise programs,

subcuta-neous fasciotomy of the involved

compartment should be considered

It is the mainstay of treatment and is

successful in relieving pain and

al-lowing a return to full activities.12,26

Endoscopically assisted,

two-incision fasciotomy is an alternative

technique purported to be as safe and

effective as single-incision fasciotomy.27

The advantages of endoscopic release

in the lower extremity are access to

the entire length of the compartment

and visualization of the superficial

peroneal nerve and its branches.27

Surgical Techniques

Anterior and Lateral Leg Compartment Fasciotomy

Surgical release of the anterior and lateral compartments is done through

a 10-cm longitudinal incision over the

anterolateral aspect of the leg in its midportion between the tibial crest and the fibula (Fig 4, A) After iden-tification of the anterior intermuscu-lar septum between the anterior and lateral compartments (Fig 4, B and C), the fascia is divided proximally

Figure 5 Either or both incisions from the two-incision fasciotomy technique can be

utilized depending on the number and location of affected compartments A, Position of two incisions (dotted line = posteromedial incision) B, Cross section of lower leg showing the

relationship of the two incisions to the four compartments 1 = anterior compartment,

2 = lateral compartment, 3 = superficial posterior compartment, 4 = deep posterior

compart-ment C, The anterior intermuscular septum D, The fascia is divided to separate the anterior

and lateral compartments The superficial peroneal nerve will be visualized (Adapted with permission from Rorabeck CH: A practical approach to compartment syndromes: III

Man-agement Instr Course Lect 1983;32:102-113.)

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and distally in both compartments

under direct visualization (Fig 4, D)

Care must be taken to identify the

su-perficial peroneal nerve before

re-lease Fasciotomy should include

in-spection for and release of any fascial

hernias

Superficial and Deep Posterior Leg

Compartment Fasciotomy

The superficial posterior, deep

posterior, and tibialis posterior

mus-cle compartments can be released

through either an extended dissection

from the lateral approach (Fig 4, D

and E) or more easily through a

sep-arate 10-cm medial incision (Fig 5 )

Once the muscular fascia is identified,

the superficial posterior compartment

can be released directly because it lies

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