ELECTROMYOGRAPHY, NERVE ACTION POTENTIAL, AND COMPOUND MOTOR ACTION POTENTIALS IN OBSTETRIC BRACHIAL PLEXUS LESIONS

Abstract OBJECTIVE Obstetric brachial plexus lesions (OBPLs) are caused by traction to the brachial plexus during labor. Typically, in these lesions, the nerves are usually not completely ruptured but form a “neuroma-in-continuity.” Even in the most severe OBPL lesions, at least some axons will pass through this neuroma-in-continuity and reach the tubes distal to the lesion site. These axons may be particularly prone to abnormal branching and misrouting, which may explain the typical feature of co-contraction. An additional factor that may reduce functional regeneration is that improper central motor programming may occur. Surgery should be restricted to severe cases in which spontaneous restoration of function will not occur, i.e., in neurotmesis or root avulsions. A major problem is how to predict whether function will be best after spontaneous nerve outgrowth or after nerve reconstructive surgery. When a decision has been made to perform an early surgical exploration, what to do with the neuroma-in-continuity can be a problem. The intraoperative appraisal is difficult and depends on experience, but even in experienced hands, misjudgment can be made. METHODS We performed an observational study to assess whether early electromyography (at the age of 1 month) is able to predict severe lesions. Additionally, the value of intraoperative nerve action potential and compound motor action potentials was investigated. RESULTS Severe cases of OBPL can be identified at 1 month of age on the basis of clinical findings and needle electromyography of the biceps. This outcome needs independent validation, which is currently in progress. Nerve action potential and compound motor action potential recordings show statistically significant differences on the group level between avulsion, neurotmesis, axonotmesis, and normal. For the individual patient, a clinically useful cutoff point could not be found. Intraoperative nerve action potential and compound motor action potential recordings do not add to the decision making during surgery. CONCLUSION The absence of a “gold standard” for the assessment of the severity of the OBPL lesion makes prognostic studies of OBPL complex. The currently available assessment strategies used to obtain the best possible solutions are discussed.

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Intraoperative nerve action and compound motor action potential recordings in patients with obstetric brachial plexus lesions

Journal of Neurosurgery ◽

10.3171/jns/2008/109/11/0946 ◽

2008 ◽

Vol 109 (5) ◽

pp. 946-954 ◽

Cited By ~ 26

Author(s):

Willem Pondaag ◽

Lieven P. A. J. van der Veken ◽

Paul J. van Someren ◽

J. Gert van Dijk ◽

Martijn J. A. Malessy

Keyword(s):

Decision Making ◽

Action Potential ◽

Brachial Plexus ◽

Root Avulsion ◽

Motor Action ◽

Severe Lesion ◽

Compound Motor Action Potential ◽

Intraoperative Assessment ◽

Nerve Action ◽

Obstetric Brachial Plexus

Object A typical finding in supraclavicular exploration of infants with severe obstetric brachial plexus lesions (OBPLs) is a neuroma-in-continuity with the superior trunk and/or a root avulsion at C-5, C-6, or C-7. The operative strategy in these cases is determined by the intraoperative assessment of the severity of the lesion. Intraoperative nerve action potential (NAP) and evoked compound motor action potential (CMAP) recordings have been shown to be helpful diagnostic tools in adults, whereas their value in the intraoperative assessment of infants with OBPLs remains to be determined. Methods Intraoperative NAPs and CMAPs were systematically recorded from damaged and normal nerves of the upper brachial plexus in a consecutive series of 95 infants (mean age 175 days) with OBPLs. A total of 599 intraoperative NAP and 836 CMAP recordings were analyzed. The severity of the nerve lesions was graded as normal, axonotmesis, neurotmesis, or root avulsion, based on surgical, clinical, histological, and radiographic criteria. Results The correlation of NAP and CMAP recordings with the severity of the lesion was assessed. The specificity of an absent NAP or CMAP to predict a severe lesion (neurotmesis or avulsion) was > 0.9. However, the sensitivity of an absent NAP or CMAP for predicting a severe lesion was low (typically < 0.3). The severity of the nerve lesion was related to CMAP and NAP amplitudes. Cutoff points useful for intraoperative decision making could not be found to differentiate between lesion types in individual patients. Conclusions Intraoperative NAP and CMAP recordings do not assist in decision making in the surgical treatment of infants with OBPLs. The authors' findings in infants cannot be generalized to adults.

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Assessment of upper extremity movement performance of patients with obstetric brachial plexus palsy

Current Directions in Biomedical Engineering ◽

10.1515/cdbme-2017-0001 ◽

2017 ◽

Vol 3 (1) ◽

pp. 1-5 ◽

Cited By ~ 1

Author(s):

Ligia C. S. Fonseca ◽

Annika K. Nelke ◽

Jörg Bahm ◽

Catherine Disselhorst-Klug

Keyword(s):

Brachial Plexus ◽

Upper Extremity ◽

Objective Data ◽

Brachial Plexus Palsy ◽

Obstetric Brachial Plexus Palsy ◽

Movement Performance ◽

Obstetric Brachial Plexus ◽

The Individual ◽

Acceleration Signals ◽

Upper Extremity Movement

Abstract:Coping strategies of patients with obstetric brachial plexus palsy (OBPP) are highly individual. Up to now, individual movement performance is assessed by visual observations of physicians or therapists - a procedure, which is highly subjective and lacks objective data. However, objective data about the individual movement performance are the key to evidence-based and individualized treatment. In this paper, a new approach is presented, which provides objective information about the upper extremity movement performance of patients with OBPP. The approach is based on the use of accelerometers in combination with a classification procedure. The movement performance of 10 healthy volunteers and 41 patients with OBPP has been evaluated by experienced physiotherapists and has been assigned to one of 4 categories representing the Mallet Scale (MS) IV to I. Three triaxial-accelerometers were placed at chest, upper arm and wrist of the affected side of the patient. Acceleration signals have been recorded during repetitive movements with relevance regarding daily life. Here, especially the results from the “hand to mouth” task are presented. From the 9 recorded acceleration signals 13 relevant features were extracted. For each of the 13 features 4 thresholds have been determined distinguishing best between the 4 patient categories of the MS and the healthy subjects. With respect to the thresholds each feature value has been assigned to the discrete numbers 0, 1, 2, 3 or 4. Afterwards, each discrete number has been weighted by a factor regarding the correlation between the feature’s value and the MS score. The resulting weighted discrete numbers of all 13 features have been added resulting in a score, which quantifies the individual upper extremity movement performance. Based on this score the movement performance of each patient has been assigned to the classes “very good”, “good”, “regular” and “bad”. All movements of the 10 healthy volunteers were classified as “very good”. The movement performance of two patients MS IV were classified as “very good” as well and the movements of the other 16 patients as “good”. The movements of the entire group of MS III patients fell into the class “regular”. Just one MS II patient was assigned to the class “regular” while the others were classified as “bad”. It was not possible to classify the movements of MS I patients. This was mainly due to the fact that none of these patients MS I was able to complete the task successfully. The developed approach demonstrated its ability to quantify the movement performance of upper extremity movements based on accelerometers. This provides an easy to use tool to assess patient’s movement strategies during daily tasks for diagnosis and rehabilitation.

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