Comparison of Two Botox Injection Techniques to Improve Gait

Not Applicable

Completed

• Conditions: Muscle Spasticity; Stroke Sequelae; Spasticity as Sequela of Stroke; Gait Disorders, Neurologic

• Registration Number: NCT07124806
• Lead Sponsor: Universidad de los Andes, Chile

Brief Summary

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.

Detailed Description

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.

Study Timeline

• Study Start: 2022-07-01
• Primary Completion: 2022-11-29
• Study Completion: 2022-12-04
• Status Verified: 2025-08
• Study First Submitted: 2025-08-08
• Study First Submitted QC: 2025-08-14
• Last Update Submitted: 2025-08-14
• Study First Posted: 2025-08-15
• Last Update Posted: 2025-08-15

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 18

Inclusion Criteria

• Hemiplegia secondary to an ischemic of hemorrhagic stroke.
• Focal spasticity of gastrocnemius muscles status 1-3 according to the modified Ashworth scale.
• Independent gait ability with or without the use of technical assistance.

Exclusion Criteria

• Spasticity status 4 according to the modified Ashworth scale.
• Focal spasticity of the tibialis posterior and/or soleus.
• Fracture and/or contracture in the lower extremities.
• Other medical treatment for spasticity.
• Allergy to the botulinum neurotoxin.
• Suffering from some infectious disease
• Pregnancy or breastfeeding

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Primary Outcome Measures

Name	Time	Method
Maximum ankle dorsiflexion during the stance phase in the paretic limb.	Before intervention (T0), three weeks (T3w) and six weeks (T6w) post botulinum neurotoxin injection	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.
Maximum ankle plantarflexion moment during the stance phase in the paretic limb	Before intervention (T0), three weeks (T3w) and six weeks (T6w) post botulinum neurotoxin injection.	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.
Foot clearance in the paretic limb.	Before intervention (T0), three weeks (T3w) and six weeks (T6w) post botulinum neurotoxin injection.	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.

Secondary Outcome Measures

Name	Time	Method
Spasticity of plantar flexor muscles using the Ashworth modified scale.	Before intervention (T0), three weeks (T3w) and six weeks (T6w) post botulinum neurotoxin injection.	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).
6-minute walk distance.	Before intervention (T0), three weeks (T3w) and six weeks (T6w) post botulinum neurotoxin injection.	Measurement of distance walked over a span of 6 minutes.
Timed up and go time.	Before intervention (T0), three weeks (T3w) and six weeks (T6w) post botulinum neurotoxin injection.	Time to complete a standing from a chair with no arms, walking 5 meters and returning to sit down.

Trial Locations

Locations (2)

Universidad de los Andes; 🇨🇱 Santiago, Las Condes, Chile

Instituto Nacional de Rehabilitación Pedro Aguirre Cerda; 🇨🇱 Santiago, Peñalolen, Chile