Abstract text (incl. figure legends and references)

OBJECTIVES

Assess the impact of the injection paradigms on muscle function and strength, assess the efficacy and safety over 10 years of repeated treatments every 3 months, identify risk factors maintaining chronicity.

METHOD:

One hundred patients were injected with a dilution ratio of 1:1 with a sterile 0.9 % saline solution, 50 patients with a 100u vial in one, 1cc tuberculin syringe, and 50 patients with a 200u vial of onabotulinum toxinA in two, 1cc tuberculin syringe during 10 years.

RESULTS

The strength of the paracervical and first portion of the trapezius muscle was altered in 6% (100u) and 18% (155u) of subjects. The second portion of the trapezius muscle was altered in 2% (100u) and 10% (155u) of subjects. Muscle function of the paracervical and first portion of the trapezius muscles was altered in 34% (100u) and 28% (155) of subjects, for the second portion of the trapezius muscle 58% (100u) and 52% (155) of subjects. The efficacy of onabotulinum toxinA was constantly maintained during the 10 years of treatment. 72% (100u), and 74% (155u) of subjects had less than 7migraine days /month (77% improvement). Early onset of migraine, comorbid emotional burden and chronic neck pain, should be considered as risk factors for the unremitting condition.

CONCLUSION

Muscle strength, and function alteration did not have an impact on esthetics of the face and on normal daily muscle function in both cohorts. In both cohorts more than 70% of patients had more than 75% improvement in monthly migraine days. Depth of the toxin injection, diffusion and presence of adipose tissue (lean versus obese patients) may be responsible for muscle strength and function alteration.