Surgical Anatomy

• 
  

  The arm is divided into two muscle compartments:

  
  
  
  
  • 
    

    The anterior compartment, which contains the biceps, the brachialis, and coracobrachialis, all innervated by the musculocutaneous nerve.

    
    
  • 
    

    The posterior compartment, which contains the triceps, which is innervated by the radial nerve.

  
  
  
  
• 
  

  The forearm is divided into three muscle compartments:

  
  
  
  
  • 
    

    The anterior or flexor compartment, which contains the muscles responsible for wrist flexion and pronation of the forearm. These muscles are innervated by the median and ulnar nerves and receive blood supply mainly from the ulnar artery.

    
    
  • 
    

    The posterior or extensor compartment, which contains the muscles responsible for wrist extension. They are innervated by the radial nerve and the blood supply is provided mainly by the radial artery.

    
    
  • 
    

    The mobile wad is a group of three muscles on the radial aspect of the forearm that act as flexors at the elbow joint. These muscles are often grouped together with the dorsal compartment. The blood supply is provided by the radial artery and the innervation by branches of the radial nerve.

  
  
  
  
• 
  

  The hand includes ten separate osteofascial compartments:

  
  
  
  
  • 
    

    The transverse carpal ligament, over the carpal tunnel, is a strong and broad ligament. The tunnel contains the median nerve and the finger flexor tendons.

  
  

General Principles

• 
  

  Common causes of upper extremity compartment syndrome include vascular injuries, severe fractures, crush injuries, extrinsic compression devices such as casts and dressings, extravasation of intravenous infusions, burns, edema from infection, and snakebites. This complication can also occur in unconscious or obtunded patients due to severe drug or alcohol intoxication and prolonged limb compression, injection of illicit drugs, and spontaneous bleeding in a muscle compartment due to pharmacological anticoagulation or bleeding disorders.

  
  
• 
  

  The diagnosis of compartment syndrome is made by a combination of clinical and lab findings and, in some cases, with measurement of compartment pressures. The most common clinical signs and findings include a tense compartment and severe pain, usually out of proportion. Characteristically, the pain becomes worse with passive stretching of the elbow, the wrist, or the fingers, depending on the site of the compartment syndrome. However, it might be difficult to elicit pain in unconscious or pharmacologically sedated patients. Other signs, such as paresthesia, pallor, pulselessness, or paralysis, may be present, and they are usually late signs. When in doubt, the compartment pressures should be measured.

  
  
• 
  

  The compartment syndrome is a potentially limb- and life-threatening condition. Renal failure due to myoglobinemia and myoglobinuria is a serious systemic complication due to delayed diagnosis and treatment. Volkmann’s ischemic contracture is another complication resulting in permanent disability. In extreme cases, it may cause muscle necrosis and limb loss.

  
  

  
  

  

  
  

  
  

  Figure 38.1 Advanced compartment syndrome of the left hand. Note the severe edema and the color changes of the skin.

  
  

  
  

  

  
  

  
  

  Figure 38.2 Delayed treatment of upper extremity compartment syndrome with muscle necrosis (a), requiring extensive muscle debridement (b).

  
  
  
  
• 
  

  Familiarity with the technique of muscle compartment pressure measurement is essential for all physicians taking care of trauma patients.

  
  
• 
  

  The normal muscle compartment pressure is <10 mmHg. Acute increase of the pressure to >30 mmHg may result in compartment syndrome, with muscle and nerve ischemia.

  
  
• 
  

  An absolute muscle compartment pressure of >30 or 40 mmHg is considered by many surgeons as a surgical emergency. An alternative to the absolute compartment pressure is the compartment perfusion pressure (CPP), as calculated by: CPP = Diastolic Pressure – Compartment Pressure. A CPP <30 mmHg is a surgical emergency and an indication for fasciotomy.

  
  
• 
  

  Reversible muscular ischemia and neuropraxia occur up to 4–6 hours of ischemia. Irreversible muscular ischemia and axonotmesis occur beyond 6 hours of ischemia.

  
  
• 
  

  The prognosis of acute compartment syndrome depends on the extent and duration of the pressure maintained in the compartment. Failure to decompress a compartment syndrome will result in progressive muscle and nerve ischemia, leading to permanent nerve damage, muscle necrosis, and myoglobinemia with kidney damage.

  
  
• 
  

  The most common muscle compartment in the upper extremity affected by compartment syndrome is the anterior (flexor) compartment of the forearm. The upper arm is the least commonly affected.

Special Surgical Instruments

• 
  

  Stryker intra-compartmental pressure measuring system, using an 18 gauge side-ported needle, should be available for measuring compartment pressures, if needed (see technique in Chapter 44 Lower Extremity Fasciotomies)

  
  
• 
  

  For vessel-loop shoelace wound closure: vessel loops and skin staples

  
  
• 
  

  Negative pressure dressing system (NPDS)

Positioning

The affected arm is placed 45° from the body on an arm board. The chest, arm, forearm, and hand are prepped into the surgical field.