(Research Hub Theater) Cadaveric Ultrasound Injection Training to Improve Targeting: Utility of a Single Ultrasound Teaching Intervention to Improve Anatomical Localization

Background and/or Objectives: Botulinum toxin (BoNT-A) injection treatment is considered first line treatment for focal spasticity management. Proper targeting of the spastic muscle(s) is imperative in order to optimize treatment outcomes. There is evidence that ultrasound improves injection accuracy, and this has led to an increase in demand for ultrasound-guided BoNT-A injection courses.

Design: Our study evaluated the improvement in the accuracy of injection technique by comparing pre and post cadaveric ultrasound education to help target commonly treated spastic muscles.

Setting: A two-day training course including didactic and hands-on ultrasound scanning using cadaveric teaching was conducted.

Participants: 12 trainees (9 PMR specialists, 1 pediatrician and 2 physician assistants) in their first 5 years of practice.

Interventions: As part of this training, participants were asked to inject 2 cadaveric muscles with acrylic paint without guidance (i.e only using their knowledge of anatomic landmarks). Then, each participant was provided approximately 5 minutes of one-to-one individualized ultrasound-teaching by two experienced instructors to localize the previously targeted muscles. Participants were then asked to reinject the same muscles using ultrasound-guidance with acrylic paint (different color).

Main Outcome Measures: An anatomist performed cadaveric dissections to evaluate discrepancies between location of the acrylic paint placement from the anatomic landmark-based technique compared to the ultrasound-guided injection technique.

Results: Cadaveric dissections showed that the anatomical landmark injection success rate was 76% (16 out of 24 muscles). Ultrasound-guided injections success rate was 92% (22 out of 24 muscles). Statistical analyses showed a significant effect of ultrasound contribution in goal achievement (p < 0.001).

Conclusions: In this pilot study, the addition of ultrasound anatomical landmarking led to a substantial improvement of on-target paint injections. These results, obtained after a single brief ultrasound training exposure, suggest that the use of ultrasound in cadaveric spasticity courses can help improve localization and targeting of key muscles in the upper and lower limb.