Why wait 3 months before doing electromyography in obstetricbrachial plexus lesions? Challenging the normMATTHEW PITTGreat Ormond Street Hospital for Children Trust – Clinical Neurophysiology, London,UK.

doi: 10.1111/j.1469-8749.2012.04326.x

This commentary is on the original article by van Dijk et al. To view thispaper visit http://dx.doi.org/10.1111/j.1469-8749.2012.04310.x

There is nothing straightforward about obstetric brachialplexus palsies (OBPPs). Even the name itself is controversial,implying the obstetrician is to blame in every case (which isnot certain). But the problems of nomenclature are as nothingwhen one considers attempts to predict prognosis. Unlike thesituation in adults, children have a much more variable prog-nosis from a variety of factors. These include luxury innerva-tion with, for example, the C7 root supplying biceps, lesseningthe impact of C5-C6 root injury.1 Also, children seem torecover better from nerve injuries than adults. Finally, even ifone was able to accurately identify those infants in whom sur-gery might be contemplated, the difficulties of grafting tinynerves – if done very early, or knowing when to remove a neu-roma in continuity when the operation is performed late –cannot be overestimated. It is, therefore, not surprising thatthere is a considerable degree of conservatism with regard tosurgery, often restricting itself to correction of the associatedsoft tissue injuries and bony deformities.

Electromyograpny (EMG) should be the premier investiga-tion. However, results have been disappointing and the expla-nations of the disparity between the findings and the laterprognosis have been a source of considerable interest. van Dijket al.2,3 have offered the most likely explanation for this dis-parity, as well as different timescales for the appearance ofsuch markers of nerve damage as fibrillation potentials. Notsurprisingly, therefore, neurophysiologists seeing thesepatients will be entitled to experience a certain sinking feeling.The technical difficulty in performing a comprehensive exami-nation, which is always distressing for infants at 3 months ofage, is considerable and even when you have finished you are

left with uncertainty as to what the results mean. The aimof the study by van Dijk et al.4 is to rationalize and reduce theneurophysiological examination to a series of simple tests thatcan be performed by any neurophysiologist.

The paper shows an EMG examination at 1 month as thebest time to give accurate prediction of later prognosis, and inthe form proposed is easily within the compass of skill of anyneurophysiologist whether they are experienced with children,or not. One omission is the determination of whether a com-bination of denervation and absent motor unit potentials hasan even stronger predictive value. It is interesting to note thateven with the theoretical prediction of fibrillation potentialsoccurring within a few days of birth, the examination at 1 weekof age found this to be an uncommon observation.

I have always been unhappy with the accepted policy of theEMG examination of children with OBPPs at 3 months ofage.5 It is very difficult to leave parents with such uncertaintyfor this long. Many obstetricians and neonatologists adopt anoptimistic approach to the recovery as they will have seencases where recovery does occur within the first few weeks.However, in those children for whom this is not the situation,it would be so much better to be able to counsel familieswhere the situation is more serious. My personal preference isto use the compound muscle action potential early on in thecourse of disease, but this is technically very difficult to per-form and uncertain in its results thus far.

If there is a major disruption of the brachial plexus with rootavulsion and significant neurotmesis, nature theoretically willnever do as well as early intervention with nerve grafting. Theresults may still be disappointing but such surgery is nevergoing to be done early enough unless patients can be identifiedmuch more quickly. With imaging not able to help at present,EMG seems the only possible way forward. However, thestandard practice of examination at 3 months of age is goingto take a lot to change. Hopefully the paper by van Dijk et al.will encourage more prompt referral to EMG and begin atransformation in management practices.

REFERENCES

1. Vredeveld JW, Blaauw G, Slooff BA, Richards R, Rozeman

SC. The findings in paediatric obstetric brachial palsy differ

from those in older patients: a suggested explanation. Dev

Med Child Neurol 2000; 42: 158–61.

2. van Dijk JG, Malessy MJ, Stegeman DF. Why is the electro-

myogram in obstetric brachial plexus lesions overly optimis-

tic? Muscle Nerve 1998; 21: 260–1.

3. van Dijk JG, Pondaag W, Malessy MJ. Obstetric lesions of

the brachial plexus. Muscle Nerve 2001; 24: 1451–61.

4. van Dijk JG, Pondaag W, Buitenhuis SM, van Zwet EW,

Malessy MJA. Needle electromyography at 1 month predicts

paralysis of elbow flexion at 3 months in obstetric brachial

plexus lesions. Dev Med Child Neurol DOI: 10.1111/j.1469-

8749.2012.04310.x. (Published online).

5. Pitt M, Vredeveld JW. The role of electromyography in the

management of the brachial plexus palsy of the newborn. Clin

Neurophysiol 2005; 116: 1756–61.

ª The Author. Developmental Medicine & Child Neurology ª 2012 Mac Keith Press 1

DEVELOPMENTAL MEDICINE & CHILD NEUROLOGY COMMENTARY