Compartment syndrome of the arm

Introduction

• A condition of increased tissue fluid pressure within a confined osteofascial space that reduces capillary blood perfusion below a level necessary for tissue viability.
• The forearm is the most common site of compartment syndrome in the upper extremity.

Anatomy

Muscles have an individual epimysial sheath surrounded by deep fascia and bone/interosseous membrane, which creates relatively non-distensible compartments.  Deep and central muscles are more affected by circulatory compromise.  Muscles bound by stiff bone or interosseous membrane are also at greater risk for compartment syndrome.

Compartments of the forearm include the dorsal compartment, volar compartment, and mobile wad.

Dorsal (Posterior) Compartment

• Muscles: Extensors, divided into deep and superficial layers ¹
  • Deep: Abductor pollicus longus, extensor pollicus brevis, extensor pollicus longus, extensor indicies, supinator
  • Superficial: Extensor digitorum, extensor carpi ulnaris, extensor digiti minimi, aconeus muscle from the long head of the triceps
  • Proximal extent = Lacertus fibrosis/pronator teres
  • Distal extent = Carpal tunnel
  • Pronator quadratus (PQ) can be considered separate compartment; isolated PQ compartment syndrome has been reported following distal radius fracture ²
  • Nerves: Posterior interosseous nerve
  • Vascular: Posterior interosseous artery

Figure 1. Dorsal (posterior) compartment of the forearm

Volar (Anterior) Compartment

• Muscles: Flexor and pronator muscles, divided by a transverse septum into deep and superficial groups by a transverse septum ¹
  • Deep compartment: Flexor pollicus longus, flexor digitorum profundus, pronator quadratus
  • Superficial compartment: Flexor carpi radialis, flexor carpi ulnaris, pronator teres, flexor digitorum superficialis, palmaris longus
  • Nerves: Median nerve and its branches, anterior interosseous nerve, ulnar nerve, deep branch of the radial nerve
  • Vascular: Major vessels of the forearm are in this compartment

Figure 2. Volar (anterior) compartment of the forearm

Mobile Wad

• Muscles: Extensor carpi radialis longus and extensor carpi radialis brevis, brachioradialis ¹
• Nerves: No important structures
• Vascular: No important structures

Figure 3. Mobile wad

Pathogenesis

Increased tissue pressure ? compression of arteriovenous structures ? ischemia ? vascular permeability ? interstitial edema ? further ischemia ? repeating cycle ? progressive cellular necrosis

Natural History

Decreased Compartment Size

• Prolonged, localized external pressure
  • Bandage/dressing/cast/pneumatic tourniquet
  • Tight fascial closure
  • Burn eschar

Increased Compartment Pressure

• Bleeding
  • Trauma/major vascular injury
  • Bleeding disorder
  • Increased capillary permeability
• Trauma (other than major vascular)
• Post-ischemic swelling
• Exercise
• Seizures
• Burns (electrical, thermal, and chemical)
• Increased capillary pressure
  • Venous obstruction
  • Muscle hypertrophy

Clinical Presentation

Patients often have a history of: ³

• Fractures
  • Most often closed fractures
  • In children, most common cause is supracondylar fractures ³
  • In adults, most common cause is fracture of the distal radius ³
    • Approximately 0.25% of distal radius fractures are complicated by compartment syndrome
• Penetrating trauma
  • Gunshot wounds and stabbings
• Drug abuse
• Crush injuries
• Intravenous infiltration
• Snake bites: Rattlesnakes, copperheads, moccasins
• Exercise: May be acute or chronic
• Infection: Strep/viral
• Newborns: From intrauterine pressure or entrapment in late pregnancy and descent

Patients often exhibit the classic 5 Ps of compartment syndrome:

• Pain (out of proportion to the injury; persistent, progressive, worse with passive stretch; most important clinical sign)
• Pallor
• Parasthesias
• Paralysis (late finding)
• Pulselessness (late finding; pressures must be >120 mm Hg to stop arterial flow)

A sixth P may also be assessed: Palpable fullness.

Diagnostic Dilemmas

Have a high index of suspicion in the following patients:

• Unconscious
• Traumatic brain injury
• Alcohol or drug intoxication
• Burns
• Language barrier

Imaging and Diagnostic Studies

Compartment syndrome is a clinical diagnosis. Several options are available for measuring compartment pressures:

• Whitesides et al⁴ recommend injection of saline into the compartment
  • Material readily available; quick, reliable
  • Pressure calculated indirectly
• Matsen et al⁵ describe a continuous infusion method
  • Allows for continuous pressure monitoring up to 3 days
  • Need pressure transducer, infusion pump
  • Concerns about infusion of saline (0.7 mL/day)
• Mubarek et al⁶ discuss using a wick catheter
  • Direct measurement of compartment pressure
  • Digital arterial monitoring system; ie, in ICUs
  • Wick gives greater surface area for equilibrium to occur more accurately
• Rorabeck et al ⁷support a slit catheter method
• Hand-held method: Stryker manometer

The normal intracompartmental pressure is 0-8 mm Hg. In acute compartment syndrome, the measured interstitial tissue pressures are greater than 30 mm Hg of the mean arterial pressure or 20 mm Hg of the diastolic blood pressure.

Classification

• Incipient: Impending; no increased compartment pressures or irreversible tissue damage yet
• Acute: Intracompartmental pressure above critical level; irreversible damage if maintained
• Subacute: No typical acute signs and symptoms, but chronic sequela develop
• Chronic: Recurrent/exercise induced
  • Transient rise in ICP after repetitive motion/exercise
  • Usually no permanent sequela, but may develop into acute compartment syndrome
    • Transient ischemia, pain, and weakness, with occasional neurologic deficits
  • Symptoms resolve over minutes to hours with cessation of activity
  • Exercise increases intracompartmental volume with increased capillary perfusion, blood volume, more interstitial edema, and muscle fiber swelling
  • If slight hypertrophy or tighter than normal fascia, then a small increase in IMP leads to problems
• Late: Irreversible damage has already occurred
  • Fasciotomy will not restore normal muscle perfusion
  • Debate about whether it is advisable to operate
    • Increased risk of infection and amputation
• Crush syndrome: Severe compartment syndrome that leads to systemic symptoms
  • Myoglobinemia
  • Hyperkalemia
  • Acidosis
  • Can lead to organ failure, death

Treatment

Medical Therapy

• Discontinue medications that can cause bleeding dyscrasias, such as heparin and warfarin
• Patient should be normotensive; hypotension can decrease perfusion pressure

Nonoperative Treatment

• Limited to “incipient” compartment syndrome
• Remove constrictive casts/dressings
  • Complete removal is more effective at reducing intracompartmental pressure than cutting and spreading
• Reposition limb/arm at heart level
• Monitor closely

Operative Treatment: Fasciotomy^1,8

Indications

• Classic history and symptoms (the best indicator is pain out of proportion to the injury)
• 6 hours of total limb ischemia
• Elevated compartment pressure
• Suspected compartment syndrome (because of the severity of sequelae, it is important not to leave a suspected compartment syndrome untreated) 

Contraindications

Cases delayed greater than 24 hours are at increased risk of infection, septicemia, amputation, and/or death.

Procedure

In a fasciotomy,⁸ the volar compartment is released first, which may improve dorsal and mobile wad compartment pressures. There are two approaches for volar release:

• Curvilinear anterior volar approach, which also releases the mobile wad
• Extended ulnar approach of Henry
  • Will need incisions for dorsal &, rarely, mobile wad

To release the dorsal compartment, a single dorsal incision is made from 3 to 4 cm distal to the lateral epicondyle toward Lister's tubercle. Some authors have argued that because of interconnection between the compartments, a volar fasciotomy can effectively decompress all compartments; however, a separate release of each compartment is more reliable.

Then, check each muscle. Release the epimysial sheath and debride necrotic tissue.

The median nerve can be released as well:

• Lacertus fibrosis
• Two heads of pronator teres
• Flexor digitorum superficialis
• Carpal tunnel

Infrequently, the ulnar nerve needs release:

• Elbow (two heads FCU)
• Proximally at Arcade of Struthers,
• Medial intermuscular septum,
• Guyon’s
  • CTR may take care of Guyons

Outcome

After release, patients may need multiple visits to the OR for wound care. Skin closure may be staged; it is important to achieve coverage for nerves, tendons, and joints.

Complications

Overall complication rate of compartment syndrome is 42%.³  The most common complication is neurologic deficits.³ Other complications include:³

• Volkmann’s ischemic contracture
• Untreated compartment syndrome with irreversible muscle and nerve damage
• Myonecrosis leads to fibroblastic proliferation
• Decreased excursion and mobility
• Gangrene
• Chronic regional pain syndrome
• Rhabdomyolysis
  • Subsequent renal failure

Pearls and Pitfalls

Compartment syndrome is a clinical diagnosis. The surgeon must be aware of the diagnosis and have a high index of suspicion in the appropriate clinical setting. Especially in cases of obtunded or intubated patients, there should be a low threshold for releasing the compartments.

Controversy

There is controversy regarding the treatment of compartment syndrome as a result of envenomation. The toxicology literature supports non-operative treatment with monitoring the patient and administration of antivenin.^8,9 The older orthopedic literature supports early release of compartment syndrome to minimize muscle death. In reviewing the literature on both sides, it appears that it would be prudent to initially treat cases of compartment syndrome secondary to envenomation with antivenin and close in-hospital monitoring.¹⁰ Compartment release may still be necessary for these cases and an early surgical consult should be obtained.

References

1. Leversedge FJ, Moore TJ, Peterson BC, Seiler Iii JG. Compartment Syndrome of the Upper Extremity. The Journal of Hand Surgery. 2011;36(3):544-559.
2. Schumer ED. Isolated compartment syndrome of the pronator quadratus compartment: a case report. The Journal of Hand Surgery. 2004;29(2)299-301.
3. Kalyani BS, Fisher BE, Roberts CS, Giannoudis PV. Compartment Syndrome of the Forearm: A Systematic Review. The Journal of Hand Surgery. 2011;36(3):535-543.
4. Whitesides TE, Haney TC, Harada H, Holmes HE, Morimoto K. A simple method for tissue pressure determination. Arch Surg 1975; 110:1311--1313.
5. Matsen FA, Mayo KA, Sheridan GW, Krugmire RB Jr. Monitoring of intramuscular pressure. Surgery 1976;79:702--709.
6. Mubarak SJ, Hargens AR, Owen CA, Garetto LP, Akeson WH. The wick catheter technique for measurement of intramuscular pressure. J Bone Joint Surg 1976;58A:1016--1020.
7. Rorabeck C, Castle G, Hardie R, Logan J. Compartmental pressure measurements: an experimental investigation using the slit catheter. J Trauma 1981;21:446--449.
8. Gold BS, Barish RA, Dart RC, Silverman RP, Bochicchio GV. Resolution of compartment syndrome after rattlesnake envenomation utilizing non-invasive measures. J Emerg Med 2003;24(3):285-288.
9. Cumpston KL. Is there a role for fasciotomy in Crotalinae envenomations in North America? Clin Toxicol (Phila). 2011 Jun;49(5):351-65.
10. Anz AW, Schweppe M, Halvorson J, Bushnell B, Sternberg M, Koman LA. Management of Venomous Snakebite Injury to the Extremities. J Am Acad Orthop Surg. 2010; 18(12): 749-59.