As the individual nerve roots emerge from the neck they join together and separate in a complex fashion in an area called the brachial plexus, running down from the neck to the axilla where the individual arm nerves emerge. Nerves are very vulnerable structures and can be injured in gunshots, direct blows, knife attacks and traction injuries, which involve a sudden stretch. The results can be very disabling, with a chronically painful arm the patient is not able to move or use very well. Recovery is very variable and many patients have to cope with a less than useful arm.
Brachial plexus injuries are most commonly caused by high speed incidents such as a motorcycle crash where the head and the shoulder region are forced apart violently by the impact of hitting the ground. Traction injuries like that, wrenching the arm away from the body with the neck stretching in the other direction are the usual mechanism of injury, with car accidents, penetrating injuries from gunshots or knives or direct damage from a hard object also contributing to this form of injury.
The number of brachial plexus lesions is difficult to estimate as they are very variable and not common, being most common in fifteen to twenty-five year old males who make up a great preponderance of trauma victims. Narakas, who treated many of these injuries, indicated his rule of seven seventies:
70% were from traffic accidents of which 70% were motorcycle accidents and 70% of these had multiple injuries
Supraclavicular injuries, involving trauma to the area above the collar bone where the brachial plexus lies, made up 70% of these multiple injuries
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.
As useful recovery may take more than eighteen months the maintenance of joint ranges, the control of swelling and the management of the chronic pain problem can be difficult. Surgery is much more effective for younger patients in terms of restoring functional strength.
Brachial plexus injuries are most commonly caused by high speed incidents such as a motorcycle crash where the head and the shoulder region are forced apart violently by the impact of hitting the ground. Traction injuries like that, wrenching the arm away from the body with the neck stretching in the other direction are the usual mechanism of injury, with car accidents, penetrating injuries from gunshots or knives or direct damage from a hard object also contributing to this form of injury.
The number of brachial plexus lesions is difficult to estimate as they are very variable and not common, being most common in fifteen to twenty-five year old males who make up a great preponderance of trauma victims. Narakas, who treated many of these injuries, indicated his rule of seven seventies:
70% were from traffic accidents of which 70% were motorcycle accidents and 70% of these had multiple injuries
Supraclavicular injuries, involving trauma to the area above the collar bone where the brachial plexus lies, made up 70% of these multiple injuries
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.
As useful recovery may take more than eighteen months the maintenance of joint ranges, the control of swelling and the management of the chronic pain problem can be difficult. Surgery is much more effective for younger patients in terms of restoring functional strength.
About the Author:
Jonathan Blood Smyth is the Superintendent of Physiotherapy at an NHS hospital in the South-West of the UK. He writes articles about back pain, neck pain, and injury management. If you are looking for Physiotherapists in Bournemouth visit his website.
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