Objective: The aim of this study was to evaluate the effect of botulinum toxin (BoNT) injections on postural evolution, pain, and functional outcomes in patients with Parkinson’s disease (PD) presenting with postural disorders, integrating both clinical assessment and patient-reported outcomes.

Background: Camptocormia (CC) and Pisa syndrome (PS) represent highly disabling conditions. The use of BoNT has been proposed as a therapeutic option, although its efficacy remains controversial.

Method: We conducted a prospective single-center study including PD patients presenting with CC +/- associated with PS. The protocol consisted of a minimum of three BoNT injections administered at 3–4 months intervals into the abdominal muscles (rectus abdominis and/or external obliquus) and repeated in case of clinical benefit. The main outcome measure was global improvement, using both clinician (CGI-I) and patient (PGI-I) Global Impression of Improvement scales. Postural measures and pain assessments were secondary outcomes.

Results: Sixty-seven patients were included (37% CC; 63% CC+PS). Postural improvement was modest according to the clinician’s assessment (18%), whereas patients reported improvement in 32% of cases. Clinicians reported stability in 40% of the cases, whereas 66% of patients reported being stable. Isolated CC remained globally stable over time, while the CC+PS group showed a slight but significant worsening of forward trunk flexion (of 5.5°; p=0.01). Pain significantly improved, particularly in the CC+PS group (from 6.2 to 5.2/10; p=0.005). Regarding secondary outcome correlations, abnormalities on muscle CT imaging were positively associated with worsening of the thoracic forward flexion angle. Treatment was well tolerated, with rare and transient adverse events.

Conclusion: To date, this is the largest prospective series reported. Botulinum toxin appears to have a limited effect on postural correction, likely reflecting the multifactorial pathophysiology of these disorders, in which dystonia may not be the predominant mechanism. Its main benefit appears to be pain reduction. The apparent discrepancy between global improvement assessed by PGI and CGI scales and objective angular measurements raises the question of the most appropriate outcome measures for evaluating BoNT efficacy in postural disorders. Larger randomized studies are needed to better define indications and optimize treatment protocols.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/postural-disorders-in-parkinsons-disease-the-role-of-botulinum-toxin-a-french-prospective-cohort/