Long-term effect of repeated lidocaine injections into the external oblique for upper camptocormia in Parkinson's disease

Background: Parkinson's disease (PD) is occasionally complicated by camptocormia. In a previous study, we classified camptocormia into upper and lower types based on the inflection point, and reported that lidocaine injection into the external oblique muscle, but not into the internal oblique or rectus abdomen, improved upper camptocormia in PD. The effect of a single lidocaine injection disappeared over a period of few days. In this study, we used repeated lidocaine injections into the external oblique for 4-5 days and evaluated the effects of such treatment for up to 90 days. Methods: The study subjects were 12 patients with PD and upper camptocormia who were treated with repeated lidocaine injections into the bilateral external oblique followed by rehabilitation. The effect of treatment was evaluated by measuring the angle of truncal flexion before and after the injection. Patients who showed improvement with repeated injections were evaluated during a 90-day period. Results: Eight out of 12 patients showed significant improvement in posture after a single lidocaine injection. However, the effect subsided several days after treatment. Repeated injections produced long-term improvement in 9 out of 12 patients, which was maintained during the 90-day observation period in eight of these patients. Conclusions: Our results showed that repeated lidocaine injections into the external oblique improved upper camptocormia, and that the effect was maintained in the majority of patients during the 90-day observation period, indicating that repeated lidocaine injections into the external oblique have therapeutic effect on upper camptocormia in patients with Parkinson's disease.