N/A
N=25
Eye Muscle Needle Electromyogram (EMu) Study
Strabismus
Bottom Line
View on ClinicalTrials.gov: NCT03895632 ↗Enrolled (actual)
25
Serious AEs
0.0%
Results posted
Aug 2020
Primary outcome: Primary: α (Slope) Parameter of the Electromyogram (EMG) Signal Power Spectral Density (PSD) Plot as Needle Approaches Then Enters Muscle. — 1.49; 2.86; 3.56 log (mV^2 / Hz) / log (Hz) — p=<0.0001
Study Design & Population
- Study type
- Observational
- Phase
- N/A
- Interventions
- —
- Age
- Adult, Older Adult · 18+ yrs
- Sex
- All
- Sponsor
- Liverpool University Hospitals NHS Foundation Trust
- Primary completion
- May 2019
Outcome Measures
| Outcome | Result | p-value |
|---|---|---|
| PRIMARY α (Slope) Parameter of the Electromyogram (EMG) Signal Power Spectral Density (PSD) Plot as Needle Approaches Then Enters Muscle. |
1.49; 2.86; 3.56 | <0.0001 sig |
| SECONDARY Clinical Score of EMG Change |
4.6 | — |
| SECONDARY Clinical Score of Needle Placement Accuracy |
87.6 | — |
| SECONDARY Clinical Score of EMG Quality. |
4.5 | — |
| SECONDARY Post-treatment Angle of Deviation |
— | — |
Summary
In some cases, strabismus, or squint, is treated with injections of Botulinum toxin (BTX) to temporarily relax the eye muscle responsible for causing the eye to be pulled to one side. Due to the deep location of the muscles, electromyogram (EMG) needle guidance is used to help ensure the toxin is delivered accurately. EMG needle guidance involves listening to the EMG signal from the tip of the delivery needle - when the needle is in the right place a sound akin to "rain on a tin roof" is heard and the BTX can be injected.
From previous research, clearly clinicians want to improve the technology of this procedure and increase the treatment efficacy and repeatability. After all, the current procedure is imprecise and subjective for what is a small target, with the eye muscles being around 2.5 mm to 4.7 mm in diameter. There may also be an increase in the likelihood of side effects such as droopy eyelids when the toxin spreads beyond the target muscle.
There is a strong need for new knowledge to improve EMG needle guidance in this context. It is hypothesised that the EMG signal could be cleaned and mined for information in real time during the procedure, thus providing the clinician with better information to guide the positioning of the needle before injecting. This pilot study will deliver the knowledge essential to indicate the feasibility of doing this. If feasible, this study will inform a full study with the aim of benefitting patients by allowing new technology to be developed to improve the treatment of strabismus with BTX.
Eligibility Criteria
Inclusion Criteria
i. Adults undergoing planned, routine EMG needle guided BTX injection into either lateral or medial rectus muscle for the treatment of strabismus.
ii. Patients being treated by Mr Yagan.
Exclusion Criteria
- Patients with Chronic progressive external ophthalmoplegia (CPEO) are excluded; a highly attenuated EMG signal is expected.
Data sourced from ClinicalTrials.gov (NCT03895632). Outcome figures and adverse-event rates are extracted automatically from the registry's posted results and are provided for clinician reference, not as a substitute for the primary publication.