Efficacy and safety of 99mTc-MIBI SPECT-guided botulinum toxin injection in parkinsonian postural abnormality

BACKGROUND: Tc-MIBI SPECT) guidance has been shown to significantly improve the efficacy of botulinum toxin (BTX) injection in dystonic postural abnormalities. But its effect in parkinsonian postural abnormalities remains unknown. METHODS: Tc-MIBI SPECT muscle metabolic imaging and baseline evaluation followed by SPECT-guided BTX injection. The primary efficacy outcome was the improvement in resting forward and lateral trunk flexion angle (RTF and RTL) at 1 month. Secondary efficacy outcomes included subjective efficacy, pain VAS score and PDQ-39 score. Adverse events (AEs) were also assessed. RESULTS: A total of 29 PD patients (14 males, 15 females) were analyzed with a mean age of 68.5 ± 8.9 years. The RTF increased (37.71 ± 16.82° vs. 40.17 ± 17.03°, Estimated Mean Difference = -2.46, 95% CI [-5.97, 1.06], p = 0.027) significantly while the RTL decreased (9.61 ± 8.78° vs. 8.28 ± 7.62°, Estimated Mean Difference = 1.34, 95% CI [-0.99, 3.67], p = 0.208) slightly at 1 month compared to baseline, though the difference was not significant. At 1 month, 4 patients (13.8%) experienced an improvement of more than 5° in RTF, 13 patients (44.8%) reported minimal to much subjective improvement and 10 patients (34.5%) saw an improvement of more than 1 point in the pain VAS score. Eleven AEs occurred, with no serious adverse events (SAEs). Related AEs mainly included transient worsening of postural abnormalities and low-back pain, which typically alleviated within 2 weeks to 2 months. CONCLUSIONS: Tc-MIBI SPECT-guided BTX treatment for parkinsonian postural abnormalities demonstrated acceptable safety but was not as effective as expected. Future studies should focus on identifying potential candidates who shall benefit from this method. CLINICAL TRIALS REGISTRATION: the Chinese Clinical Trial Registry, number ChiCTR2000039775, Nov. 8th, 2020.