The Influence of Dynamic Polyelectromyography in Surgical Planning of Spastic Elbow Deformities

Past Studies 

Past Studies indicate spastic limb deformities can occur when there is an imbalance of muscle forces across a joint. This can result as a consequence of stroke, traumatic brain injury, and cerebral palsy. Studies have shown that there is considerable variability in the patterns of muscle control in deformities that involve a bent or flexed elbow, since there are several muscles that cross the elbow. Information about what each muscle contributes to joint movement is useful in the assessment as a whole. Historically, physicians have used clinical examination to evaluate the muscles involved with deformities that are related to muscle stiffness after brain damage. Analysis of involved muscles by dynamic electromyography and motion data can provide more specific information necessary for successful treatments, including surgery. Dynamic electromyography involves recording the electrical activity of muscles as they are stretched passively or as they move actively, in order to tell whether those muscles “turn on” when they are supposed to or at the wrong time. Motion data can show how quickly the elbow moves and can show whether any slowing in movement is related to muscles that have turned on at the same time. Despite the logic behind polyelectromyographic analysis, research is lacking regarding its specific contribution to clinical and surgical decision making. The clinical usefulness of polyelectromyographic analysis has remained unproven.

This Study

This Study examined the surgical planning process of two different surgeons for 21 persons with spastic elbow flexion deformity. Each surgeon formulated a detailed surgical plan for each individual tendon unit. Participants then underwent motor-control analysis in which kinetic (muscle movement) and polyelectromyographic data were collected by using a standard protocol. Each surgeon formulated another surgical plan after independently reviewing the laboratory study.

After the surgeons reviewed the data, their frequency of change and degree of agreement in the surgical plans were used as measures for the effect of the laboratory studies. After the motor-control studies, 57% of the surgical plans were changed. The frequency of change did not differ by clinical years of experience by the surgeon. There was a trend toward higher agreement between the surgeons after the motor control studies than before.

Who May Be Affected By These Findings

Persons with brain or spinal cord damage and spastic elbow flexion deformity, health care providers, researchers, and surgeons

Caveats

The authors state that the ultimate question is whether motor-control analysis improves the functional abilities of people after surgery. This study reports an increase in muscle movement after surgery; however, this study did not assess how functional those movements were. The authors state that polyelectromyographic analysis could enhance non-surgical treatments, such as muscle specific injected medications. These are areas for future research.

Bottom Line

In this study, detailed electromyographic motor-control analysis altered surgical planning for persons with spastic elbow flexion deformities. Clinical assessment alone did not accurately identify the muscles responsible for the deformity or dysfunction. Greater clinical experience possessed by a surgeon did not reduce the need for or the effect of dynamic polyelectromyographic analysis on surgical planning. Motor-control analysis produced higher agreement between the two surgeons who were planning these surgeries. Dynamic polyelectromyographic analysis lead to excellent clinical outcomes in the surgical treatment of spastic elbow flexion deformity. Future research is needed to determine whether motor-control analysis improves the functional outcome of surgery.

 

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