From the outside you wouldn't know by looking at the forearm that there are three separate compartments. Each section is separated by connective tissue called fascia. The hand has 10 of these compartments. There are a total of 15 compartments in the entire upper extremity (arm) from shoulder to hand. Any condition that changes the pressure in a compartment can reduce blood flow (called ischemia) and cause death of the tissues (necrosis).
Injuries that increase pressure in any one of these compartments can result in a condition called acute compartment syndrome (ACS). The most common cause of ACS is a bone fracture. Repetitive exercise (muscle contractions over and over) is another potential risk factor for ACS. Other causes of ACS of the upper extremity include dressings, tourniquets, or casts that are too tight. Bleeding disorders and burns can also increase the amount of fluid (called fluid volume) inside a compartment. And remember, these compartments are tightly packed with very little room for extra fluid. In a smaller number of cases, swelling from a spider or snake bite can also lead to ACS.
In this review article, hand surgeons bring us up to date on the diagnosis and treatment of ACS of the upper extremity. They begin by brushing up on the anatomy and descriptions of the compartments. Drawings help show the various compartments and the contents of each one. Muscles, tendons, nerves, and blood vessels are clearly labeled.
For the surgeon, a clear understanding of where each compartment begins and ends is important when making incisions to release pressure in the affected compartment. The necessary procedure to restore circulation and save the arm is called a fasciotomy. The surgeon makes long slits in the fascia to allow it to open and spread. Without release of the pressure within the compartment, the loss of blood flow can result in serious loss of arm and hand function. In severe cases, amputation may be the recommended treatment.
The decision to perform a fasciotomy is based on patient symptoms, clinical presentation (how the arm looks when examined), and pressure measurements taken inside the compartments. For mild to moderate increases in pressure, the patient is closely monitored by taking serial measurements. These same measurements are used to confirm that the compartments have returned to normal after surgical decompression. Each compartment must be measured separately. Special monitoring devices are used. Sometimes more than one compartment needs releasing.
The authors provide step-by-step drawings and descriptions of fasciotomies of the forearm and hand. Where to make the incisions with length and depth at each location are provided. How successful is this procedure? That depends on a number of different variables. For example, the patient's age and medical condition can affect outcomes.
Likewise, the type of injury, cause, and severity all play a role in the results. Early treatment has the best chance for good results with fewer complications. The longer a patient waits between injury and treatment, the greater the risk of problems such as infection, nerve damage, amputation, and even death.
One other serious problem that can develop is called Volkmann ischemic contracture. The long period without blood to the soft tissues inside the affected compartment(s) can cause irreversible damage. The muscles go into full contraction and cannot let go or relax. The patient's hand, forearm, and/or upper arm assume a telltale position, which is called Volkmann contracture.
Patients who progress to the point of having a Volkmann contracture are not likely to regain full use of the affected area even with surgical treatment. Additional surgeries such as muscle or tendon transfers may be needed.
In summary, any cause of increased pressure inside one or more of the 15 separate compartments of the upper extremity can be a very serious, even life threatening condition. Symptoms of pain, swelling, and tense tissue (especially with muscle contractures) are red flag findings. An early diagnosis of acute compartment syndrome (ACS) and immediate treatment are essential for a good outcome. In severe cases, patients should be counseled not to expect full recovery of motion, strength, or function of the involved arm.
Reference: Mark L. Prasarn, MD, and Elizabeth A. Oullette, MD. Acute Compartment Syndrome of the Upper Extremity. In Journal of the American Academy of Orthopaedic Surgeons. January 2011. Vol. 19. No. 1. Pp. 49-58.