Efficacy of single-photon emission computed tomography aided botulinum toxin injection in cervical dystonia: A double-blind, randomized study.

BACKGROUND: Although single-photon emission computed tomography (SPECT/CT) could help to predetermine dystonic muscles in patients with cervical dystonia (CD), its efficacy in aiding botulinum toxin injection is undetermined. This randomized, double-blinded study aimed to assess the efficacy of SPECT/CT aided botulinum toxin injection in CD. METHODS: Patients were randomized into study group (candidate muscles selected by SPECT/CT and clinical evaluation) or control group (clinical evaluation). Follow-ups were done at two weeks (T1), one (T2), three (T3) and six months (T4). The primary outcomes included symptom improvement assessed using Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) and Tsui score at T2. RESULTS: A total of 122 patients were enrolled and 108 patients accomplished the study. For primary outcomes, the study group had significantly better symptom improvement at T2 (TWSTRS: ß, -4.86 [95%CI -9.40 to -0.32; P = 0.036]; Tsui: ß, -1.65 [95%CI -2.77 to -0.54; P = 0.004]). For secondary outcomes, the study group also showed better outcomes at T1 (TWSTRS: ß, -6.33 [95%CI -10.17 to -2.49; P = 0.001]; Tsui: ß, -1.42 [95%CI -2.48 to -0.37; P = 0.008]) and T3 (TWSTRS: ß, -6.05 [95%CI -11.09 to -1.01; P = 0.019]; Tsui: ß, -1.24 [95%CI -2.40 to -0.08; P = 0.037]). The interval of re-injection was significantly longer in the study group than the control group (159.1 ± 28.6 versus 141.8 ± 51.0 days, P = 0.032). CONCLUSIONS: SPECT/CT could improve the efficacy of botulinum toxin in CD. It could become a useful tool to aid botulinum toxin injection.

The efficacy of single-photon emission computed tomography in identifying dystonic muscles in cervical dystonia.

INTRODUCTION: The key point for botulinum toxin type A injection in treating cervical dystonia is to accurately identify dystonic muscles. This study aimed to evaluate the efficacy of technetium-sestamibi single-photon emission computed tomography in identifying target muscles in cervical dystonia. METHODS: In the study group (n = 18), target muscles were selected according to clinical evaluation combined with technetium-sestamibi single-photon emission computed tomography, while in the control group (n = 18), target muscles were selected by clinical evaluation alone. All patients were followed-up at 2 weeks, 1, 3 and 6 months after botulinum toxin type A injection. The primary outcomes were the reduction rates in Toronto Western Spasmodic Torticollis Rating Scale and Tsui score at 1 month. RESULTS: Although the reduction rates in Toronto Western Spasmodic Torticollis Rating Scale and Tsui scores were not different between the two groups at 2 weeks and 1 month, the reduction rates in both scores were significantly higher in the study group at 3 and 6 months. The number of patients receiving re-injection within 6 months was significantly lower in the study group. Also, the re-injection interval was significantly longer in the study group. In the study group, more deep cervical muscles were injected, which concerns especially semispinalis capitis, longissimus capitis, and obliques capitis inferior muscles. CONCLUSION: technetium-sestamibi single-photon emission computed tomography is a useful method for screening target muscles in cervical dystonia. It helps clinicians draw a 'blueprint' for the distribution of dystonic muscles before botulinum toxin type A injection.