Validity and reliability of dry needle placement in the deep lumbar multifidus muscle using ultrasound imaging: an in-vivo study

Objectives: To use ultrasound (US) imaging to determine the validity and reliability of needle placement of two dry needling (DN) protocols for the lumbar multifidus (LM) in individuals with a high body mass index (BMI).

Methods: Twenty-one participants with a BMI higher than 25 kg/m² completed the study. A US scanner was used to determine the location of needle placement after a 100 mm long needle was inserted in the LM at L4 and L5 following two DN protocols for the deep LM muscle. US images were saved and viewed 6 months later to determine the intra-tester reliability.

Results: The probability of reaching the deep LM muscle was high (85-95%) at L4 and L5. Although the needle reached a bony landmark 85-100% of the time, it only reached the vertebra lamina as intended 70-75% of the time. The intra-tester reliability of needle placements based on analysis of real-time and recorded US images was poor-to-moderate.

Conclusions: Although the bony drop may not indicate that the needle has reached the vertebra lamina as the protocol intended, reaching a bony drop is still meaningful as it coincided with reaching the LM in the majority of participants.