Injection of Onabotulinum Toxin A into the Bilateral External Oblique Muscle Attenuated Camptocormia: A Prospective Open-Label Study in Six Patients with Parkinson's Disease

Introduction: Camptocormia (severe bending of the spine) is a debilitating complication of Parkinson's disease (PD) without established treatment. Botulinum toxin (BT) may be beneficial, but data is scarce regarding the efficacy of administration of BT into the bilateral external oblique (EO) muscle for treatment of camptocormia in PD.

Methods: Six patients with PD and camptocormia, with flexion of the thoracic spine, were enrolled in the study. BT (75 or 90 units, onabotulinum toxin A) were injected into each EO bilaterally under sonographic guidance. Camptocormia angle (CA) was defined as the angle between the acromion-greater trochanter line and a vertical line. CA and disabling symptoms were evaluated during the treatment course.

Results: Two weeks after the injection of BT, the mean CA showed significant attenuation [median (interquartile range); 38° (23.5°) vs. 18° (21°), p = 0.028]. Subjective relief was present in cases 1-3 and 6, and absent in cases 4 and 5. Cases 1-3 received repeated injections to maintain the amelioration; in cases 1 and 2, this was for 1 year or longer, while falls of case 3 limited the amelioration.

Conclusion: Botulinum therapy into bilateral EO attenuated the angle of thoracic-level camptocormia in six patients with PD over the observation period of 2 weeks. The reproducibility of the results, long-term efficacy, and subjective relief of symptoms require further examination.