Disclosures: Brian Malave, BA: No financial relationships or conflicts of interest

Objective: To determine the accuracy and safety of EMG needle localization of the cervical multifidus muscle, which is commonly studied in the electrodiagnostic work-up of a cervical radiculopathy. To our knowledge, this has not been validated before.

Design: Experimental study

Setting: Anatomy laboratory

Participants: 2 cadavers

Interventions: We performed needle insertions at three different cervical levels – C5, C7, and T2. Each cervical level had 3 injections per multifidus muscle (6 injections total) – one done at a 45 degree angle caudally and laterally, another at 45 degree angle cranially and laterally, and the last at a 45 degree angle laterally only. Insertion was always 2.5cm lateral to spinous process. Injections were first done with acrylic paint to determine needle endpoint, and then with wire to determine needle pathway. A total of 72 injections were performed.

Main Outcome Measures: Whether the acrylic paint identified the multifidus muscle of interest, and whether the wire was close ( < 5mm) to any nerve, artery, vein, or spinal cord.

Results: No insertion was within 5mm of a nerve, artery, or spinal cord. Only 27% of wires remained in multifidus muscle, although they allowed for good visualization of the pathway the needle took. Acrylic paint allowed for better determination of needle endpoint. There was 100% accuracy of localization of the cervical multifidus muscle on acrylic paint analysis.

Conclusions: Our proposed protocol for EMG needle localization of the cervical multifidus muscle is safe, accurate and reproducible.

Level of Evidence: Level III

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PM&R Meeting Abstracts - https://pmrjabstracts.org/abstract/what-a-pain-in-the-neck-determining-accuracy-of-emg-needle-localization-of-cervical-multifidus-muscle/