Safety of dry needling to the upper lumbar spine: a pilot cadaver study

ABSTRACT

Objective: When inserting a dry needle laterally into the upper lumbar spine (L1-L3) there is an increased risk of piercing the kidney; therefore, the objective of this study was to determine a zone of safety for practitioners to needle in the upper lumbar spine.

Methods: Ten cadavers were screened for inclusion. L1 spinous process was identified and confirmed with ultrasound imaging. A digital caliper was used to measure laterally at 1.5 cm, 2.0 cm, and 2.5 cm. Dry needles were inserted maximally at each point and a binary decision, yes or no, was made to determine if bony contact was made. Needle depth and abdominal width measurements were also recorded. Safety of the dry needling procedure was interpreted as such if bony contact was made by the needle. If bony contact was made, then it was assumed that the needle cannot advance further into pleura or kidney.

Results: Forty-four percent of needles did not make bony contact at 2.5 cm lateral of the L1 spinous process, whereas 22% did not make bony contact at 1.5 cm and 2.0 cm. There was a weak to moderate negative correlation between abdominal width measurements and needle depth at 1.5 cm (−0.48) and 2.0 cm (−0.45), and at 2.5 cm (−0.39).

Conclusion: A safety zone of needling less than 2.5 cm is likely safe, but needs to be confirmed with future study. Dry needling 2.5 cm lateral appears more risky due to the higher frequency of not contacting a bony backdrop.

KEYWORDS:

• Ultrasound imaging
• lumbar spine
• low back
• safety
• kidney

Acknowledgments

We would like to acknowledge the contributions of individuals and their families who donate their bodies to the University which aid in the education and research of health-care providers.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Notes on contributors

CJ Mansfield

CJ Mansfield is a Fellow of the American Academy of Orthopedic Manual Physical Therapists and is working towards becoming a clinician scientist with a focus on understanding the effects of dry needling on acute and chronic musculoskeletal pathologies.  He is pursuing his PhD training through the School of Health and Rehabilitation Sciences at OSU and works as a physical therapist in the Sports Medicine department at OSU.

M Harr

M Harr is is an undergraduate student at OSU with an interest in research regarding biomechanics, sports medicine, and  low back injuries.

M Briggs

M Briggs is a clinical assistant professor in the Department of Orthopaedics, researcher at the Sports Medicine Research Institute, lecturer in the Division of Physical Therapy and also serves as the director of the Sports Physical Therapy Residency for Sports Medicine.

J Onate

J Onate main research focus is developing functional motion assessment research that bridges the gap across research to clinical systems to allow for evidence-based outcomes for aiding individuals to sustain optimal health and performance throughout their careers and lives. He is an associate professor and co-director of the Sports Medicine Movement Analysis and Performance program.

LC Boucher

LC Boucher is an assistant professor and her research focuses on pediatric injury biomechanics and more recently has started to explore the role of using musculoskeletal ultrasound in teaching physical exam skills, exploring how tissue responds to stress, as well as applications to aid in clinical decision making.