The limbs contain muscles in compartments enclosed by bones, fascia and interosseous membrane. A rise in pressure within these compartments due to any reason may jeopardize the blood supply to the muscles and nerves within the compartment, resulting in what is known as compartment syndrome.
Acute compartment syndrome (ACS) most often develops after significant traumas, particularly those involving long bone fractures. This syndrome may also occur following non-traumatic causes, although such incidents are less frequent. Acute compartment syndrome caused by leukemic infiltration of the muscles is uncommon but has sometimes been documented in acute leukemia or non-Hodgkin lymphoma. It is rare for acute compartment syndrome to occur in the chronic phase of chronic myeloid leukemia (CML).
Almost all orthopedic surgeons come across acute compartment syndrome (ACS) in their clinical practice. Dr. Volk- mann, a German doctor in 1881, described Acute compartment syndrome by reporting the hand contracture which was a consequence of this particular ular condition. In 1888, Petersen for the first time reported the management of acute compartment syndrome. The compartment syndrome is mostly diagnosed with variation in clinical symptoms and signs in sequential examinations. If the diagnosis is missed and left untreated, it can lead to serious damage to the soft tissues of the limb including muscles, nerves, and vessels. It can sometimes result in limb loss or even Loss of Life. An orthopedic surgeon must have an understanding of this condition, including specific injuries and specific group of patients which are more vulnerable in acute compartment syndrome. A surgeon should understand the basics of compartment syndrome including pathophysiology, epidemiology, diagnosis, and management.
Compartment syndrome is defined as a condition in which a closed compartment's pressure increases to such an extent that the microcirculation of the tissues in that compartment is diminished. Two factors are responsible for this condition, either a decrease in a compartment volume or an increase in the contents of a compartment, or sometimes both of these factors act at the same time. Acute compartment syndrome develops when the intra-compartmental pressure (ICP) exceeds the venous capillary pressure. Elevated ICP results in raised pressure at the venous capillary end and increases hydrostatic pressure, leading to arteriolar compression. The microcirculation is compromised due to arteriolar compression, hence reducing or diminishing perfusion of the tissues. Inadequate perfusion and oxygenation result in soft tissue ischemia and anoxia and death of the cells. The most ischemic vulnerable tissue in a compartment is skeletal muscle. Extent of muscle death is dependent on the duration of ischemia, temperature of the tissues, and the available residual microcirculation. Sufficient collateral blood supply and lower local temperature slow down the ischemic process. Rorabeck and Clarke showed that the duration of increased pressure is significant in the return of neurological function. Pressures 40 to 80 mm Hg sustained for 4 hours do not cause permanent nerve dysfunction, but when applied for 12 hours or more, permanent neurological changes occurred. In conclusion, the amount of skeletal muscle necrosis is directly proportional to the duration of ischemia and inversely proportional to temperature.
Compartment syndrome can be diagnosed early by high index of suspicion. Excessive pain, not relieved with usual doses of analgesics, in a patient with an injury known to cause compartment syndrome must raise an alarm in the mind of the treating doctor. Injuries with a high risk of developing compartment syndrome are as follows: Supracondylar fracture of the humerus, Forearm bone fractures closed tibia fractures, Crush injuries to the leg and forearm. 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 direction opposite to that of the damaged muscle's action. (example: passive extension of fingers produces pain in the flexor compartment of the forearm).
Other signs include a tense compartment, hypo-aesthesia in the distribution of involved nerves, muscle weakness etc. Compartment syndrome can be confirmed by measuring compartment pressure. A pressure higher than 40 mm of water is indicative of compartment syndrome. Pulses may remain palpable till very late in impending compartment syndrome, and should not provide a false sense of security that all is well.
A close watch for an impending compartment syndrome and effective early preventive measures like limb elevation, active finger movements etc. can prevent this serious complication. Early surgical decompression is necessary in established cases. This can be performed by the following methods: Fasciotomy: The deep fascia of the compartment is slit longitudinally (example: in forearm). Fibulectomy: The middle third of the fibula is excised in order to decompress all compartments of the leg.