f Post graduate mcqs and discussion : Compartment syndrome

Thursday, March 22

Compartment syndrome

The contain muscles in compartments enclosed by bones , fascia and interosseous membrane. Arise in pressure with in these compartments due to any reason may jeopardize the blood supply to muscles and nerves within the compartment,  resulting in what is known as " the compartment syndrome " .

Fig: osseo-facial compartments 

Causes : the rise in compartment pressure can be due to any of the following reasons :

# any injuries leading to oedema of the muscles
# fracture haematoma within the compartment.
# ischemia to compartment,  leading to muscle oedema.

Consequences : the increased pressure with in the compartment compromises the circulation leading to further muscles ischemia . A viscous cycle is thus initiated and continues until the total vascularity of the muscles and nerves within the compartment is jeopardized.  Results in ischemic muscles necrosis and nerves damage.  The necrotic muscles undergoes healings with fibrosis,  leading to contractures . Nerve damage may result in motor and sensory loss.

In extreme case, gangrene may occur. 

Diagnosis : compartment syndrome can be diagnosed early by high index of suspicion.  Excessive pain not relieve by usual dose of analgesic,  in a patient's with an injury known to cause compartment syndrome must raise an alarm in the mind of treating doctors.  Injuries with high risk of developing compartment syndrome are as follows :

Supracondylar fracture of the humerus
Forearm bone fractures
Closed tibial fracture
Crush injuries to leg and forearms.

Stretch test : this is the earliest sign of impending compartment syndrome.  The ischemic muscles,  when stretched,  give rise to pain . It is possible to stretch the affected muscles by passively moving the joints in a direction opposite to that of the damaged muscles action ( passive extension of fingers produce pain in flexor compartment of forearm. )

Other signs include a tense compartment , hypoanesthesia in the distribution of involved nerves , muscles weakness and etc. It can be conformed by measuring compartments pressure.  A pressure higher than 40 mm of water is indicative of compartment syndrome.  Pulse may remain  palpable till very late in impending compartment syndrome,  and should not provide a false sense of security that all is well.

Treatment : A close watch for an impending compartment syndrome and effective early preventive measures like limb elevation,  active finger movements and etc can prevent this serious complications.  Early surgical decompression is necessary in established cases . This can be performed by the following methods :

Fasciotomy : the deep fascia of compartment is slit longitudinally ( e.g. : forearms )

Fibulectomy : the middle 3rd of fibula is excised in order to decompress all compartment of the legs .