Sep 23 2009
Brachial Plexus Lesions | ArticlesBase.com
At the side of the neck on each side the nerves exit from the spinal areas at each level and join and separate in a complicated manner in what is anatomically called the brachial plexus. This nerve collection runs down from the neck to the armpit where it separates into the individual nerves of the arm. The plexus is well placed to be easily injured in knife wounds, bullet wounds, sudden traction (stretch) and direct blows. Because of the severity of the injury and limited recovery, a brachial plexus lesion can leave someone with a painful arm of very limited use.
Motorcycle injuries are the most common mechanism of brachial plexus injury, with severe traction occurring as the shoulder and head hit the ground, forcing the two structures apart and stretching the nerves severely. Wrenching the arm violently away from the body is a typical injury, with high speed car injury also providing many victims. Penetrating injuries from attacks with knives or guns or direct trauma from falls from a height or blunt objects can also give a brachial plexus injury.
It is difficult to estimate the number of this kind of injury and overall they are not common, with males in the 15 to 25 years old group affected preferentially as they are in many kinds of trauma. Narakas, a doctor, indicated his rule of seven seventies to explain the occurrence of these injuries:
Traffic accidents made up 70% of injuries and 70% were on motorcycles, of which 70% had multiple injuries
70% of these had supraclavicular injuries, damaging the area above the collar bone where the brachial plexus lies
70% of supraclavicular injuries involved one nerve root being avulsed (pulled out of the spine) and 70% of those were lower nerve roots in the neck, 70% of which generate a chronic pain problem.
If the neck and shoulder are moved apart suddenly with force there can be severe injury to the nerves of the brachial plexus with the nerve damage varying from a limited stretch to total nerve rupture from the spinal cord. If the connections are avulsed close to the spinal cord the picture is more serious and less likely to recover or be amenable to surgery. Further away from the spinal cord any rupture is more likely to have a good outcome. C5 and C6 injuries, the higher nerve roots, are more often damaged when the incident occurs with the arm by the side. C8 and T1 injuries, the lower nerve roots, are more likely injured when the arm is pulled suddenly overhead by the trauma.
A detailed examination of the arm may be necessary in a case of multiple injuries to ensure a brachial plexus lesion is not present. Typical symptoms are pain in the shoulder and neck, heaviness and weakness in the arm and abnormal sensations such as abnormal pain feelings or pins and needles. The shoulder can be very swollen and vascular injury from blood vessel traction should be suspected if pulses are absent or reduced. Medical examination of the reflexes, motor power and sensibility is performed to establish the nerves which have been injured and the degree of their injury. Testing for this can be difficult as nerve anatomy is variable and experience is necessary for interpretation.
Typical past management of brachial plexus injuries was conservative, the patient recovering from the injury and the doctors would monitor the changes in the muscle power and sensibility over 12-18 months. Once the time had elapsed the remaining restrictions were considered permanent although small changes could still occur with time. The arm was treated surgically to make it more useful as a tool or by amputating it if it was in the way. Typical management now is surgical, with early exploration of open injuries (e.g. knife wound) and direct repair of nerves. In blunt trauma this might be delayed.
During the long period waiting for any improvement, often up to 18 months, it is difficult to manage the problems such as development of chronic pain, arm swelling and maintenance of the normal ranges of the joints. Physiotherapists are closely involved in the maintaining of healthy joints and the strengthening of recovering muscles. The restoration of functional muscle strength by surgical intervention is more predictable in younger people.
About the Author:
Jonathan Blood Smyth, editor of the Physiotherapy Site, writes articles about Physiotherapy, back pain, orthopaedic conditions, neck pain, injury management and physiotherapists in Birmingham. Jonathan is a superintendant physiotherapist at an NHS hospital in the South-West of the UK.
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