An interventional study of Botulinum toxin guided by ultrasonography and anatomical references and Botulinum neurotoxin guided by ultrasonography and in vivo location of innervation zones guided by high-density electromyography in Muscle Spasticity, Stroke Sequelae and Spasticity as Sequela of Stroke, sponsored by Universidad de los Andes, Chile. Completed at 2 sites in Chile. Per ClinicalTrials.gov, last updated 2025-08-15.
Sponsored by Universidad de los Andes, Chile · Not applicable, Interventional, and Treatment
According to our hypothesis, the use of HD-EMG shall allow an accurate localization of the innervations zones of the muscles, offering a better complement to the methodology applied so far to define the botulinum neurotoxin (BoNT) injection site. To achieve that goal, a randomized clinical trial comparing the effectiveness of two guiding methods to define the BoNT injection site in the gastrocnemius muscles will be conducted. One arm will be guided with ultrasonography + localized IZ using anatomical references; while the second arm with ultrasonography + in vivo location of the IZ through HD-EMG. The effectiveness will be evaluated by changes in functional tests and in biomechanical parameters of the gait assessed with a three-dimensional motion analysis system. These outcomes will be measured at baseline (T0), at three (T3w) and six weeks (T6w), post BoNT injection. The differences between sessions will be evaluated as measurements of effectiveness. We expect that greater effectiveness will be found in the group that receives the injection of BoNT, guided by the in vivo location of the IZ.
This research proposal seeks to improve the current procedures to determinate the botulinum neurotoxin (BoNT) injection site. More precisely, we propose to complement the ultrasonography with an in vivo location of the IZ, using a non-invasive technique based on surface multielectrode electromyography grid, which is called high density-surface EMG (HD-EMG). According to our hypothesis, the use of HD-EMG shall allow an accurate localization of the IZs of the muscles, offering a better complement to the methodology applied so far to define the BoNT injection site. To achieve that goal, a randomized clinical trial comparing the effectiveness of two guiding methods to define the BoNT injection site in the gastrocnemius muscles (main ankle extensors or plantar flexors) will be conducted. One arm will be treated with the best available option, which includes ultrasonography + localized IZ using anatomical references. The second arm will be managed using ultrasonography + in vivo location of the IZ through. The last will be measured using HD-EMG by recording the motor unit action potentials along the muscle fibers. This technique can identify the location of the IZ by the change of phase of those potentials. The effectiveness will be evaluated by changes in biomechanical parameters of the gait, assessed using a three-dimensional motion analysis system. The outcomes will be biomechanical gait variables associated with the ankle joint (ankle joint moment, dorsiflexion range, among others) and functional tests (spasticity using Ashworth scale, 6-minute walk test and the Timed Up and Go Test). These outcomes will be evaluated at baseline (T0), at three (T3w) and six weeks (T6w), post BoNT injection. The differences between sessions will be evaluated as measurements of effectiveness (Delta1 = T3w-T0; Delta2 = T6w - T0). To compare the effectiveness between groups, these delta values will be compared using a student's t-test or a Mann-Whitney U test, as appropriate. Also, a Cohen's d will be calculated to determine the magnitude of these differences. In addition, the post-hoc power (1-β) will be measured. All statistical analyses will be performed in the STATA software (version 14.0 Stata-Corp LP, USA), considering a one tailed analysis, and a confidence level of 95%. Statistically significant differences will be considered those associated with a p-value lower than 0.05. We expect to find greater effectiveness in the group that receives the injection of BoNT, guided by the in vivo location of the IZ using HD-EMG.
704 studies on the registry are indexed under Muscle Spasticity; 149 are open to participants now.
This study's enrollment of 18 is below the median of 36 across 525 interventional studies indexed under Muscle Spasticity.
Browse Muscle Spasticity studies →Universidad de los Andes, Chile is the lead sponsor of 44 studies on the registry; 13 are open to participants now.
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Exclusion Criteria:
Patients will be treated with a botulinum neurotoxin (BoNT) injection into the medial and lateral gastrocnemius muscles of the paretic hemi-body. This injection will be guided by ultrasonography and anatomical references described in the EUROMUSCULUS/USPRM guideline.
Combination Product: Botulinum toxin guided by ultrasonography and anatomical references
Patients will be treated with a botulinum neurotoxin (BoNT) injection into the medial and lateral gastrocnemius muscles of the paretic hemi-body. However, in this case the injection will be guided by ultrasonography and the in vivo location of the innervation zones using noninvasive multielectrode electromyography.
Combination Product: Botulinum neurotoxin guided by ultrasonography and in vivo location of innervation zones guided by high-density electromyography
The botulinum neurotoxin (BoNT) will be calculated according to the weight of each patient. It will be injected in four places: two of them into the medial gastrocnemius and the other two into the lateral gastrocnemius. For medial gastrocnemius muscle, ¼ of the dose will be injected into the muscle belly at the 25% of the distance between the popliteal fossa and the intermalleolar line. Another ¼ will be injected into the muscle belly at the 35% of the previously mentioned distance. For lateral gastrocnemius, ¼ of the dose will be injected into the muscle belly at the 20% of the distance between the popliteal fossa and the intermalleolar line. The remaining ¼ of the dose will be injected into the muscle belly at the 30% of the previously described distance. All patients will conduct the same physical therapy program and under the direction of the same team of physical therapists. This program will begin two weeks after receiving the BoNT injection.
Also known as: Botox injection
The botulinum neurotoxin (BoNT) will be calculated according to the weight of each patient. It will be injected in eight places: four will be located in vivo for gastrocnemius medialis and four for gastrocnemius lateralis. These places will correspond to innervation zones located by high-density electromyography in different zones of each muscle. Thus, each of the eight located innervation zones will receive 1/8 of the calculated dose for the gastrocnemius muscle. All patients will conduct the same physical therapy program and under the direction of the same team of physical therapists. This program will begin two weeks after receiving the BoNT injection.
Also known as: Botox injection, Linear electrode array electromyography
Maximum ankle dorsiflexion during the stance phase in the paretic limb.
Peak dorsiflexion angle during the stance phase in the paretic limb. This value will be calculated from Vicon Nexus 2.12 software, using the conventional gait model + functional calibration, and will be considered as the average value within 8 to 10 gait cycles.
Time frame: Before intervention (T0), three weeks (T3w) and six weeks (T6w) post botulinum neurotoxin injection
Maximum ankle plantarflexion moment during the stance phase in the paretic limb
Peak internal ankle dorsiflexion moment during the stance phase in the paretic limb. This value will be calculated from Vicon Nexus 2.12 software, using the conventional gait model + functional calibration, and will be considered as the average value within 8 to 10 gait cycles.
Time frame: Before intervention (T0), three weeks (T3w) and six weeks (T6w) post botulinum neurotoxin injection.
Foot clearance in the paretic limb.
Minimum distance between the lowest point on the shoe and the ground during the swing phase in the paretic limb. This value will be calculated from a custom-made biomechanical model, and will be considered as the average value within 8 to 10 gait cycles.
Time frame: Before intervention (T0), three weeks (T3w) and six weeks (T6w) post botulinum neurotoxin injection.
Spasticity of plantar flexor muscles using the Ashworth modified scale.
Qualitative evaluation of the increase in ankle plantar flexors tone during a muscle stretch movement (dorsiflexion). This will be scaled from 0 (no increase in muscle tone) to 4 (ankle rigid during dorsiflexion movement).
Time frame: Before intervention (T0), three weeks (T3w) and six weeks (T6w) post botulinum neurotoxin injection.
6-minute walk distance.
Measurement of distance walked over a span of 6 minutes.
Time frame: Before intervention (T0), three weeks (T3w) and six weeks (T6w) post botulinum neurotoxin injection.
Timed up and go time.
Time to complete a standing from a chair with no arms, walking 5 meters and returning to sit down.
Time frame: Before intervention (T0), three weeks (T3w) and six weeks (T6w) post botulinum neurotoxin injection.
Plan to share: Yes — Study protocol and statistical analysis plan will be published. Statistical analysis plan includes all databases used in the study. These databases will not include personal information of patients.
Supporting information: Study protocol, Sap
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Universidad de los Andes, Chile