history of a previous child with brachial plexus injury
Erbs (73%), Total Plexus (25%), Klumpke’s (2%)
Right > Left
4% bilateral (correlated with breech)
Nerve Injuries Seddon Classification (1943):
This is the least severe injury - a localized conduction block of the nerve. It can be
caused by streching or compression of the nerve. The axons inside the nerve remain intact, but there may be segmental demyelination of the nerve. Because there is no terminal structural damage to the nerve, this type of injury usually recovers quite quickly.
The sheath of the nerve remains intact, but there is axonal disruption. The axons
can regenerate, and near to complete recovery can be expected in the injuries where the motor targets are close enough.
This is an injury where the nerve has been ruptured. There will be no or very little recovery without surgical intervention.
Neuroma-in-continuity: In some cases, the nerve has begun to rupture, but the rupture is incomplete. In such cases, the nerve can develop a neuroma
The most severe type of injury is an avulsion, in which the nerve root has been torn out of the spinal cord.
Lower roots 4x more likely than upper roots to avulse. Upper roots more likely to rupture(88%) than avulse.
Roots of C5 and C6 are anchored to the transverse process by a dense fibrous sheath and gives them more protection from avulsion.
Lower roots do not have this attachment, weakest point (elastic limit) is the point at which the roots leave the spine
The degree of injury is inversely proportional to the length of the nerve – the elastic limit of a short nerve is more quickly exceeded compared to a longer nerve. C5 and C6 injuries are more common as they are shorter nerves.
poorer return of function in conservatively managed lower root injury versus similarly managed upper root injury.
In breech deliveries, upper roots also tend to be avulsed
Classification of Severity Medical Research Council Scale
M0 - No contraction
M1 - Flicker contraction
M2 - Muscle contraction with active motion with gravity eliminated
M3 - Full range of motion against gravity
M4 - Full range of motion against gravity with some resistance
Cervical xrays – fractures of the transverse processes might indicate avulsions of the corresponding roots, due to the attachments of the deep cervical fascia between the cervical roots and the transverse processes
Humeral/elbow xrays – potential radial, ulnar, median nerve injuries
In children with a persistent, passively tight, internal rotation contracture of the shoulder to rule out a posterior glenohumeral dislocation.
Accuracy of predictability is not the same for all roots
Avulsed roots can exist despite a normal myelogram.
Better to perform the myelography at least 1 month after the injury to allow for the pseudomeningocele to be sealed and to prevent the dye from flowing freely to the surrounding spaces.
Advantage of good visualization of the brachial plexus beyond the spinal foramen.
Visualization of intradural portion of the rootlets is difficult due to the insufficient contrast between the subarachnoid space and the neural structures, a problem caused mainly by cerebrospinal fluid pulsatility.
Overall sensitivity 81 percent. 50% for root avulsions
Study of paraspinal muslces help diagonose root avulsions
SNAP’s and somatosensory potentials improve the accuracy of the diagnosis
Normal sensory conduction velocities in conjunction with a flail anesthetic arm implies root avulsion,
Electromyography (EMG) and nerve conduction studies are less useful for patients with OBPP than they are for adults with brachial plexus injuries.
With electromyography, fibrillations are associated with denervation and will become apparent approximately 3-6 weeks following injury.
Motor unit potentials suggest reinnervation or collateral sprouting.
In general, EMG findings may be misleadingly optimistic.
Most surgeons believe that clinical examination is a better prognostic indicator than is EMG.
MANAGEMENT 1) Treat life threatening injuries
2) Look for associated Injuries
fractures of the clavicle, cervical transverse processes, or winged scapula
Very poor prognosis with scapulothoracic dissociation
Lower trunk lesions
Maintain Passive range
Serial followup to look for improvement
Criteria for surgery – remains controversial
Clinical motor testing is the key factor for selecting patients for surgery
Most use recovery of biceps function as indicator
More accurate if use recovery of multiple muscle groups rather than just using one.
Gilbert recommends surgery if biceps recovery is not evident by 3 months, Waters suggests waiting until 4 months, and Strombeck discouraged using deltoid or biceps activity at 3 months as the criterion for surgical intervention and came to the conclusion that children with little or no deltoid and biceps activity at 6-9 months were more appropriate candidates.
Clarke has developed an active movement scale and scores recovery to determine the need for surgery. At 9 months, the infant is assessed with the cookie test, which requires the child to put a cookie to his or her mouth with limited neck flexion. If the infant does not pass the cookie test, then surgery is recommended.
Shenaq - global injury that
does not improve by 3 months of age;
lack of motor function of one or more muscle units (elbow flexors, shoulder abductors and external rotators, and wrist and finger flexors) at 3 to 6 months
grade I-II muscle units with no progress at 6 months or beyond
Results of the spontaneous recovery following obstetrical palsy:
Landmark study “thesis of Tassin” / Gilbert et al
44 children followed for 10 years / no surgical intervention
Analysis: complete recovery possible if deltoid and biceps M1 by 2nd month
Results good but incomplete if recovery of biceps and deltoid by 3-3.5 months
Highly unsatisfactory results if biceps not M3 by 5 months