Hallazgos aguja electromiografía de los puntos gatillo en zona del cuello-hombro antes y después del tratamiento de inyección

OBJECTIVES:

Evaluate the electromyographic findings in the trigger points [TrPs] of 31 patients, suffering from myofascial pain syndrome in the neck-shoulder area, before and after injection treatment.

METHODS:

One hundred and seventy-two TrPs and 31 reference points were studied with needle-electromyography and then the TrPs were injected via the same needle with small doses of either botulinum toxin A [BTA] or saline in a double-blind study.

RESULTS:

In the baseline, the occurrence of spontaneous electrical activity containing endplate spikes [EPS] was 23.3 percent in all the TrPs and 9.7 percent in the reference points. This difference did not reach statistical significance, but the difference was statistically significant in the TrPs of upper trapezius [P = 0.02 on the left and 0.04 on the right side]. We found complex repetitive discharges in 3.5 percent of studied TrPs, but not at any of the reference points. At four weeks after the BTA treatment, fibrillation potentials were found in 31.3 percent of the TrPs against none in the saline group [P < 0.001]. Injections of BTA reduced the mean prevalence of EPS in TrPs significantly [P < 0.05] when compared with saline injections. The change of EPS prevalence correlated with the subjective result of treatment assessed on verbal scale, but not with other pain measurements.

CONCLUSIONS:

In our clinical study the occurrence of spontaneous electrical activity containing spikes was not specific to TrPs, but more common in some TrPs of the neck-shoulder area than in the painless point in deltoid muscle. The change of EPS prevalence may be related to the treatment outcome of TrPs.