Birth injuries of the brachial plexus

Interrater reliability of electrodiagnosis in neonatal brachial plexopathy

INTRODUCTION

We investigated interrater reliability of overall assessment of nerve root lesions by electrodiagnostic testing (EDX) in neonatal brachial plexus palsy (NBPP).

METHODS

Two blinded, board-certified reviewers retrospectively reviewed de-identified EDX data from 37 infants with NBPP for 2005-2012. Only nerve conduction and electromyography needle data were included. The examiners independently assigned 1 of 4 nerve root lesion categories: (1) pre-ganglionic lesion (avulsion), (2) post-ganglionic lesion (rupture), (3) normal, or (4) "unable to determine." Simple percentage agreement, the Cohen kappa statistic representing interrater reliability for each nerve root (C5-T1), and overall kappa between examiners were evaluated.

RESULTS

Interrater reliabilities were substantial to almost perfect for each nerve root except C5. Considering all nerve roots, overall interrater reliability was substantial (kappa = 0.62); simple percentage agreement was 75% (138/185).

CONCLUSIONS

Interrater reliability of nerve root assessment by EDX for infants with NBPP was high for C6-T1 root levels, but less reliable for C5 because of technical factors. Muscle Nerve 55: 69-73, 2017.

Bone discrepancy as a powerful indicator for early surgery in obstetric brachial plexus palsy

OBJECTIVES

One of the unfortunate sequelae in obstetric brachial plexus palsy (OBPP) is upper limb length discrepancy. However, the influence of primary nerve reconstruction remains undetermined. In this study, the resultant discrepancy in children with OBPP who underwent primary reconstruction was analyzed in relation to the severity of the lesion, the timing of surgery, and the functional outcome following surgery.

METHODS

Fifty-four patients that met the inclusion criteria were included in this study. Preoperative and postoperative bilateral scanograms were obtained to document the effect of reinnervation on bone growth. The length of the humerus, ulna, third metacarpal, third proximal phalange, and total limb length were measured and the percentage between the affected and normal side were accessed. Correlations between all the measures of limb length and measures of active motion (i.e., three different classification systems) were performed.

RESULTS

Spearman's rank correlation coefficients revealed significant correlations between limb length discrepancies and nearly all measures of active upper extremity movement. The timing of surgery and the severity of the lesion significantly influenced the resultant limb length discrepancy.

CONCLUSIONS

The prevention of a non-acceptable upper limb discrepancy is fundamental for both the patient and family. The extent of the resultant discrepancy appeared to be strongly related to the time between injury and surgery, degree of severity, and the outcome of surgery. Patients with better functional recoveries of the affected upper extremities showed smaller differences in limb length.

Motor nerve-conduction studies in obstetric brachial plexopathy for a selection of patients with a poor outcome

BACKGROUND

The criteria and timing for nerve surgery in infants with obstetric brachial plexopathy remain controversial. Our aim was to develop a new method for early prognostic assessment to assist this decision process.

METHODS

Fifty-four patients with unilateral obstetric brachial plexopathy who were ten to sixty days old underwent bilateral motor-nerve-conduction studies of the axillary, musculocutaneous, proximal radial, distal radial, median, and ulnar nerves. The ratio between the amplitude of the compound muscle action potential of the affected limb and that of the healthy side was called the axonal viability index. The patients were followed and classified in three groups according to the clinical outcome. We analyzed the receiver operating characteristic curve of each index to define the best cutoff point to detect patients with a poor recovery.

RESULTS

The best cutoff points on the axonal viability index for each nerve (and its sensitivity and specificity) were <10% (88% and 89%, respectively) for the axillary nerve, 0% (88% and 73%) for the musculocutaneous nerve, <20% (82% and 97%) for the proximal radial nerve, <50% (82% and 97%) for the distal radial nerve, and <50% (59% and 97%) for the ulnar nerve. The indices from the proximal radial, distal radial, and ulnar nerves had better specificities compared with the most frequently used clinical criterion: absence of biceps function at three months of age.

CONCLUSIONS

The axonal viability index yields an earlier and more specific prognostic estimation of obstetric brachial plexopathy than does the clinical criterion of biceps function, and we believe it may be useful in determining surgical indications in these patients.