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Brachial plexus injury

 
Neurological Disorder:

Brachial plexus injuries

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Definition

Brachial plexus injuries affect the nerves that originate from the spinal cord behind the head and neck (cervical nerves).

Description

The brachial plexus are nerves that leave the cervical vertebrae (but originate in the brain) and extend to peripheral structures (muscles/organs) to transmit motor and sensory nerve impulses. The brachial plexus consists of several cervical nerve roots, which include: C4, sending fibers to the shoulder and trapezius muscle; C5, sending fibers to the deltoid muscle and sides of upper arm or distal radius and involved with shoulders abduction; C6, involved with elbow flexion and fibers in the biceps and lateral forearm and thumb; C7, fibers to the triceps muscle, index and middle finger tips and involved with elbow extension; and C8, involved with extension of thumb and 4th and 5th fingers. Injury to the brachial plexus can involve avulsion injuries (nerve torn from attachment to the spinal cord), which are the most serious type of injury; neuroma injuries, due to injury causing scar formation tissue, which compresses nerves; rupture injuries, nerve is torn, but not at the spinal cord; and stretch injuries, nerve is damaged, but not torn.

Sports related injuries to the the cervical spine are common, especially injury to cervical vertebra 5 (C5) and C6. Erb described this condition with paralysis in 1874. Other names for the disorder include "burner" or "stinger" syndrome and cervical nerve pinch syndrome. Traumatic sports injury to the brachial plexus is characterized by a classical symptom—burning sensation that radiates down an upper extremity. The sensation may be short lived (2 minutes) or in chronic cases may last as long as two weeks. There are three common mechanisms that cause BPI, which include: direct impact to Erb point resulting in brachial plexus compression; traction caused by lateral flexion opposite from affected side; and nerve compression caused by hyperextension of the neck.

Obstetrical brachial plexus paralysis (OBPP) refers to injury to all or part of the brachial plexus during delivery. The condition was first described by Smellie in 1764 who described bilateral (both arms) paralysis in the newborn. Klumpke described paralysis (of the lower plexus) in 1885. Erb described paralysis of the upper brachial plexus (upper C5-C6 nerve damage) in 1874. Lower brachial plexus injuries are called Klumpke palsies and upper brachial plexus injury are termed Erb palsies. Injury is rare but is more prevalent in neonates born by cesarean delivery.

Demographics

In the United States a true measurement of new and existing cases is undetermined largely due to the significant underreporting of injuries. Approximately 5% of all peripheral nerve injuries results from trauma to the brachial plexus. Research studies conducted on college football players reported approximately 45% to 65% experience BPI during their collegiate careers. Additionally, it is estimated that there is an 87% recurrence rate. Estimates in other countries are not possible due to significant underreporting.

The incidence (number of new cases) of OBPP ranges from 0.2–4% of live births globally. The World Health Organization estimates the worldwide incidence is approximately 1–2%. In the United States it is rare and the incidence is 0.2% of live births. Every year 1–2 babies per 1000 live births are affected by obstetrical brachial nerve injury.

Causes and symptoms

BPI typically occurs as a result of a blow to the head, shoulder, and/or Erb point in an athlete during a contact sport. There are two grades of BPI. Grade 1 occurs when there is an interruption of nerve function due to demyelination. Muscle weakness is often detected soon after injury. Grade 2 describes more extensive damage to deeper and vital nerve areas (axons). Muscle weakness is often present and if persistent could mean a higher-grade lesion. Further tests for grade 2 BPI are indicated to fully assess the extent of nerve degeneration.

The causes of OBPP include shoulder dystocia, large birth weight, and breech delivery (vertex presentation accounts for 94–97% of cases). Maternal diabetes (mother has diabetes) is associated as a risk factor. Mothers who have had several children who were recorded to be large babies have an increased risk for delivering neonates with OBPP.

Commonly, affected athletes complain and describe burning and/or numbness in the neck, shoulder, or upper extremity (affected arm). Symptoms typically occur after a blow to the head or shoulder. These symptoms include burning sensation in the neck, pain in the neck, (also called dysesthesias), and a feeling of weakness or "heaviness" in the affected arm. Bilateral (on both arms) numbness possibly indicates a more severe form of cervical cord injury. Symptoms can last from a few seconds to weeks.

Infants affected by OBPI may present with flail arms at birth. The affected arm may be internally rotated and pronated and devoid of elbow and shoulder movement (Erb palsy). If brachial plexus paralysis is present the entire hand and arm is flail with no movement ability.

The symptoms of OBPP can be grouped according to Sunderland's classification, which was proposed in 1951. A first-degree injury (also called neuropraxia or "stretch injuries") involves nerve injury that can completely resolve within 12 weeks. A second-degree injury results in severe trauma and nerve compression, but essential nerve elements are still intact and complete recovery is expected. A third-degree nerve injury is more severe, and essential nerve structures have been damaged as well as possible muscle damage. Some nerves and muscles may be permanently damaged. A fourth-degree injury results from extensive nerve damage that affects muscles, and typically it requires corrective surgical repair. The most severe form of obstetrical brachial plexus injury is fifth-degree injury, which is complete transaction of the nerve (the nerve is completely cut).

Diagnosis

A careful history, physical examination, and testing are essential for diagnosis. The clinician must suspect cervical fracture and/or spinal cord injury in an athlete presenting with altered consciousness. If the patient is awake and alert a complete neurological examination is indicated. The patient's mental status should be immediately assessed. Cervical nerve root assessment for detection of motor and sensory deficits is essential. A special test called the Spurling test is performed. During the Spurling test, the cervical spine is extended and head rotated toward the affected shoulder while loading axial weight. The purpose of manipulating the neck in this fashion is to reproduce the symptoms of the BPI. A positive Spurling test will reproduce symptoms. Clinical examination on-site at the time of injury typically includes; grip strength, identification of specific symptoms, duration of symptoms; assessment of motor impairment; assessment of cervical range of motion (only if no cervical fracture is present). Lab tests are generally not required and imaging studies are routinely limited to radiographic (x-ray) studies, taken from different views. Higher resolution studies such as MRI and CT scans can be utilized in cases where cervical spine or cervical nerve root damage is suspected. Use of a special test to detect the extent of muscle damage (electromyography) can help to localize lesions and confirm the diagnosis. No specific lab tests are useful in the diagnostic process.

For infants with BPI due to delivery complications an assessment scale called the Active Movement Scale (7-point scale) can determine impairment from no contraction to full motion in the absence of or against gravity. This scale can help to assess arm movement impairment caused by nerve damage. The extent of nerve damage can be classified according to Sunderland. Typically, a lack of clinical evidence of elbow flexion by the 3rd or 4th month of life is indication for surgical repair of damaged nerves.

Treatment team

The treatment team for sports-related BPI typically includes the immediate responders (coach, team physician). Further consults from a comprehensive team can include a primary care practitioner, neurologist, physical therapist, and possibly a medical pain specialist.

For patients with OBPP a complete team of special nursing care and specialists is usually indicated. For surgical candidates, a specialist in neurosurgery or an orthopedic spine surgeon is essential. The pediatrician and pediatric neurologist play a vital role in assessment and provide information to parents. Long-term rehabilitation may be necessary in severe cases.

Treatment

On-site treatment for sports-related BPI typically includes mobilization and icing of the affected region. Treatment of BPI can be divided into three phases: the acute phase, recovery phase, and maintenance phases. Treatment during the acute phase typically involves physical therapy and medical issues (i.e., further imaging studies). Surgery may be required. During the recovery phases, physical therapy continues and the patient is monitored to continue follow-up care. During the maintenance phase of treatment physical therapy continues. The goal for medication is to prevent complications and help alleviate pain. Typically analgesics such as the anti-inflammatory type or an opiate narcotic are recommended. Analgesia may also help the affected person to cope better with physical therapy sessions. Typical opiate-narcotics include Lortab, Norcet, or Vicodin. Nonsteroidal anti-inflammatory drugs (NSAIDs, e.g., Motrin, Ibuprin) have both anti-inflammatory and analgesic effects.

For infants with OBPI medical treatment initially focuses on protection of ligaments, joints, and tendons from stress. Physical therapy may be indicated for movement exercises. Surgical intervention may be necessary if patients do not show recovery of neurological function by four months of age. Some controversy exists in the United States, with some surgeons advocating surgery on patients younger than 4 months.

Recovery and rehabilitation

Rehabilitation for BPI primarily entails physical therapy (PT) during the entire treatment course (acute, recovery, and maintenance treatment phases). The focus of PT during the acute phases primarily involves early mobilization and icing. Patients attempt to improve cervical range of motion to strengthen cervical muscles. During the recovery phases, special PT programs attempt to strengthen cervical muscles to a level of performance prior to injury. Special focus on muscles supporting the injured brachial plexus nerve (i.e., cervical and shoulder regions) is emphasized. Treatment for the maintenance phases primarily focuses on continuation of cervical muscle strength and conditioning. Clinical findings during examination and testing are key factors for determining return to play and recovery. A full recovery of affected muscle is necessary to prevent recurrence of burner syndrome and further injury. An athlete in a contact sport, who has fully recovered, is capable of supporting his or her weight at the neck leaning at a 45 degree angle. Some athletes may have some asymmetry of affected muscles that persists, and care should be taken as the athlete returns to contact sport participation.

Most infants with OBPI spontaneously recover (92-95% of reported cases) because the nerve injury is usually minor. Initial rehabilitation can include physical therapy to maintain passive range of movement. Surgery may be necessary for severe cases that require special postoperative care, monitoring, and physical therapy. Recovery for children with OBPP depends on the severity of nerve injury. Recovery after surgery is variable given that results depend on extent of damage to nerves and successful repair if surgery is indicated.

Prognosis

Prognosis for sports-related BPI is generally good. Some athletes develop a chronic complicated condition with symptoms called chronic burner syndrome. Most cases of nerve injury in infants are self-limiting and spontaneously resolve. Severe cases may require surgery. Surgical candidates typically have severe nerve injury and must undergo microsurgery to repair nerve damage.

Special concerns

In sports-related injury medical/legal problems can exist because cervical spine injury is sometimes not considered the cause of symptoms. Overlooking BPI can result in further damage to peripheral nerves.

Resources

PERIODICALS

Clancy, W. G. "Upper Trunk brachial plexus injuries in contact sports." American Journal of Sport Medicine 5, no. 5 (1977).

WEBSITES

Brachial plexus injury. http://www.mayoclinic.org.

Brachial plexus injury. http://www.cincinnatichildrens.org.

Laith Farid Gulli, M.D.

Robert Ramirez, D.O.


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Wikipedia: Brachial plexus injury
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Home > Library > Miscellaneous > Wikipedia
Brachial plexus injury
Classification and external resources
ICD-10 G54.0, P14.3, S14.3
ICD-9 353.0, 767.6, 953.4
DiseasesDB 31267
MeSH D020516

The brachial plexus is a network of nerves that conducts signals from the spinal cord, which is housed in the spinal canal of the vertebral column (or spine), to the shoulder, arm and hand. These nerves originate in the fifth, sixth, seventh, and eighth cervical (C5-C8), and first two thoracic (T1-T2) spinal nerves, and innervate the muscles and skin of the chest, shoulder, arm and hand. Brachial plexus injuries, or lesions, are caused by damage to those nerves.[1][2][3]

Brachial plexus injuries, or lesions, can occur as a result of shoulder trauma, tumours, or inflammation. The rare Parsonage-Turner Syndrome causes brachial plexus inflammation without obvious injury, but with nevertheless disabling symptoms.[1][4] But in general, brachial plexus lesions can be classified as either traumatic or obstetric. Obstetric injuries may occur from mechanical injury involving shoulder dystocia during difficult childbirth.[5] Traumatic injury may arise from several causes. "The brachial plexus may be injured by falls from a height on to the side of the head and shoulder, whereby the nerves of the plexus are violently stretched....The brachial plexus may also be injured by direct violence or gunshot wounds, by violent traction on the arm, or by efforts at reducing a dislocation of the shoulder joint".[6]

Contents

Causes

In most cases the nerve roots are stretched or torn from their origin, since the meningeal coverings of the nerve roots are thinner than the sheaths enclosing the peripheral nerves. The epineurium of the peripheral nerve is contiguous with the dural mater, providing extra support to the peripheral nerves.

Brachial plexus lesions typically result from excessive stretching; from rupture injury where the nerve is torn but not at the spinal cord; or from avulsion injuries, where the nerve is torn from its attachment at the spinal cord. A build-up of scar tissue around a brachial plexus injury site can also put pressure on the injured nerve, disrupting innervation of the muscles. Although injuries can occur at any time, many brachial plexus injuries happen during birth: the baby's shoulders may become impacted during the birth process causing the brachial plexus nerves to stretch or tear. Obstetric injuries may occur from mechanical injury involving shoulder dystocia during difficult childbirth, the most common of which result from injurious stretching of the child's brachial plexus during birth, mostly vaginal, but occasionally Caesarean section. The excessive stretch results in incomplete sensory and/or motor function of the injured nerve.[2][5]

Traumatic brachial plexus injuries brachial plexus injury may arise from several causes, including sports, high-velocity motor vehicle accidents, especially in motorcyclists, but also all-terrain-vehicle (ATV) accidents. Injury from a direct blow to the lateral side of the scapula is also possible. The severity of nerve injuries may vary from a mild stretch to the nerve root tearing away from the spinal cord (avulsion). "The brachial plexus may be injured by falls from a height on to the side of the head and shoulder, whereby the nerves of the plexus are violently stretched...The brachial plexus may also be injured by direct violence or gunshot wounds, by violent traction on the arm, or by efforts at reducing a dislocation of the shoulder joint".[6]

Brachial plexus lesions can be divided into two types:

  1. An upper brachial plexus lesion, which occurs from excessive lateral neck flexion away from the shoulder. Most commonly, forceps delivery or falling on the neck at an angle causes upper plexus lesions leading to Erb's palsy.[6] This type of injury produces a very characteristic sign called Waiter's tip deformity due to loss of the lateral rotators of the shoulder, arm flexors, and hand extensor muscles.[2][7]
  2. Much less frequently, sudden upward pulling on an abducted arm (as when someone breaks a fall by grasping a tree branch) produces a lower brachial plexus lesion, in which the eighth cervical (C8) and first thoracic (T1) nerves are injured "either before or after they have joined to form the lower trunk. The subsequent paralysis affects, principally, the intrinsic muscles of the hand and the flexors of the wrist and fingers".[6] This results in a form of paralysis known as Klumpke's paralysis.[6][8]

Injury Classification

The severity of brachial plexus injury is determined by the type of nerve damage.[1] There are several different classification systems for grading the severity of peripheral nerve and brachial plexus injuries. Most systems attempt to correlate the degree of injury with symptoms, pathology and prognosis. Seddon's classification, devised in 1943, continues to be used, and is based on three main types of nerve fiber injury, and whether there is continuity of the nerve.[9]

  1. Neurapraxia: The mildest form of nerve injury. It involves an interruption of the nerve conduction without loss of continuity of the axon. Recovery takes place without wallerian degeneration.[9][10]
  2. Axonotmesis: Involves axonal degeneration, with loss of the relative continuity of the axon and its covering of myelin, but preservation of the connective tissue framework of the nerve (the encapsulating tissue, the epineurium and perineurium, are preserved).[9][11]
  3. Neurotmesis: The most severe form of nerve injury, in which the nerve is completely disrupted by contusion, traction or laceration. Not only the axon, but the encapsulating connective tissue lose their continuity. The most extreme degree of neurotmesis is transsection, although most neurotmetic injuries do not produce gross loss of continuity of the nerve but rather, internal disruption of the nerve architecture sufficient to involve perineurium and endoneurium as well as axons and their covering. It requires surgery, with unpredictable recovery.[9][12]

A more recent and commonly used system described by the late Sir Sydney Sunderland,[13] divides nerve injuries into five degrees: first degree or neurapraxia, following on from Seddon, in which the insulation around the nerve called myelin is damaged but the nerve itself is spared, and second through fifth degree, which denotes increasing severity of injury. With fifth degree injuries, the nerve is completely divided.[9]

Presentation (Signs and Symptoms)

Signs and Symptoms may include a limp or paralyzed arm, lack of muscle control in the arm, hand, or wrist, and lack of feeling or sensation in the arm or hand. Although several mechanisms account for brachial plexus injuries, the most common is nerve compression or stretch. Infants, in particular, may suffer brachial plexus injuries during delivery and these present with typical patterns of weakness, depending on which portion of the brachial plexus is involved. The most severe form of injury is nerve root avulsion, which results in complete weakness in corresponding muscles. This usually accompanies high-velocity impacts that occurs during motor vehicle or bicycle accidents.[2]

The cardinal signs of brachial plexus injury then, are weakness in the arm, diminished reflexes, and corresponding sensory deficits.

  1. Erb's palsy. "The position of the limb, under such conditions, is characteristic: the arm hangs by the side and is rotated medially; the forearm is extended and pronated. The arm cannot be raised from the side; all power of flexion of the elbow is lost, as is also supination of the forearm".[6]
  2. In Klumpke's paralysis, a form of paralysis involving the muscles of the forearm and hand,[14] a characteristic sign is the clawed hand, due to loss of function of the ulnar nerve and the intrinsic muscles of the hand it supplies.[7][15]

Diagnosis

The diagnosis may be confirmed by an EMG examination in 5 to 7 days. The evidence of denervation will be evident. If there is no nerve conduction 72 hours after the injury, then avulsion is most likely.[citation needed].

Treatment

Treatment for brachial plexus injuries includes occupational or physical therapy and, in some cases, surgery. Some brachial plexus injuries may heal without treatment. Many infants improve or recover within 6 months, but those that do not have a very poor outlook and will need further surgery to try to compensate for the nerve deficits.[1][5] The ability to bend the elbow (biceps function) by the third month of life is considered an indicator of probable recovery, with additional upward movement of the wrist, as well as straightening of thumb and fingers an even stronger indicator of excellent spontaneous improvement. Gentle range of motion exercises performed by parents, accompanied by repeated examinations by a physician, may be all that is necessary for patients with strong indicators of recovery.[2]

To relieve symptoms associated with this type of injury, common drugs include Lyrica and Sesamet.[citation needed].

Prognosis

The site and type of brachial plexus injury determine the prognosis. Avulsion and rupture injuries require timely surgical intervention for any chance of recovery. For milder injuries involving build-up of scar tissue and for neurapraxia, the potential for improvement varies, but there is a fair prognosis for spontaneous recovery, with a 90 - 100% return of function.[1][2]

See also

References

  1. ^ a b c d e "NINDS Brachial Plexus Injuries: Information Page". National Institute of Neurological Disorders and Stroke. Last updated September 29 2008 - see bottom of webpage). http://www.ninds.nih.gov/disorders/brachial_plexus/brachial_plexus.htm. Retrieved 2009-10-11. 
  2. ^ a b c d e f "Brachial Plexus Injury: Description & illustrations". Cincinnati Children's Hospital, health information website. (revision 9/09 - see bottom of webpage). http://www.cincinnatichildrens.org/health/info/neurology/diagnose/brachial-plexus.htm. Retrieved 2009-10-11. 
  3. ^ Glanze, W.D., Anderson, K.N., & Anderson, L.E, ed (1990). Mosby's Medical, Nursing, and Allied Health Dictionary (3rd ed.). St. Louis, Missouri: The C.V. Mosby Co.. ISBN 0-8016-3227-7.  p.165
  4. ^ "Parsonage-Turner Syndrome". Who Named It? (whonamedit.com). Date unclear. http://www.whonamedit.com/synd.cfm/1910.html. Retrieved 2009-10-11. 
  5. ^ a b c A.D.A.M Healthcare center
  6. ^ a b c d e f Warwick, R., & Williams, P.L, ed (1973). Gray’s Anatomy (35th ed.). London: Longman.  pp.1046
  7. ^ a b "Neurology notes". MrCPass.com. (modified 3-10-2009 - see bottom of webpage). http://www.mrcpass.com/Notes/Neurology%20Notes.pdf. Retrieved 2009-10-11. 
  8. ^ Bienstock, A., & Kim, J.Y.S. (Updated July 13 2009). "Brachial Plexus Surgery article, with overview of brachial plexus injury". Emedicine. http://www.emedicine.com/plastic/topic450.htm. Retrieved 2009-10-11. 
  9. ^ a b c d e Tavaris, Marcio Pessanha (Publication date unclear). "Classification of nerve injuries". MEDSTUDENTS - Neurosurgery. http://www.medstudents.com.br/neuroc/neuroc4.htm. Retrieved 2009-10-08. 
  10. ^ Glanze, W.D., Anderson, K.N., & Anderson, L.E (1990), p.805
  11. ^ Glanze, W.D., Anderson, K.N., & Anderson, L.E (1990), p.117
  12. ^ Glanze, W.D., Anderson, K.N., & Anderson, L.E (1990), p.810
  13. ^ Ryan, G.B. (August 1995). "Obituary: Professor Emeritus Sir Sydney Sunderland (1910-1993)" (PDF). Journal of Anatomy 187(Pt1): 249–251. doi:?. PMID 1167365. http://www.pubmedcentral.nih.gov/picrender.fcgi?artid=1167365&blobtype=pdf. Retrieved 2009-10-08. 
  14. ^ Glanze et al. (1990) p.667
  15. ^ "Scrub Notes: Pope's Blessing Vs. Claw Hand". http://scrubnotes.blogspot.com/2008/02/popes-blessing-vs-claw-hand.html. Retrieved 2009-10-11. 

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