73 - Evaluation of a Novel Denervation Technique to Relieve Lower Back Pain: A Cadaveric Feasibility Pilot Study

Poster Board Number: 73
There are separate poster presentation times for odd and even posters.
Odd poster #s – first hour
Even poster #s – second hour

Co-authors:

John Tran, PhD - Assistant Professor, Division of Anatomy, Department of Surgery, University of Toronto; Timothy Wilson, PhD - Associate Professor, Anatomy and Cell Biology, Western University; Eldon Loh, MD, FRCP(C) - Physiatrist; Associate Professor, Department of Physical Medicine and Rehabilitation, Lawson Health Research Institute; Western University

Abstract Body : Introduction: Facetogenic low back pain due to osteoarthritis accounts for approximately 15-45% of chronic low back pain cases, and figures heavily in the $6-12 billion spent annually on low back pain treatments by the Canadian medical system alone. Radiofrequency ablation (RFA) is a treatment for this condition, which uses needles carrying electrodes at their distal tips to be inserted in precise areas of the spine. Controlled heat lesions produced by electrodes intentionally damage the medial branches of lumbar dorsal rami – the nerves responsible for transmitting pain from osteoarthritic facet joints. Clinical outcomes vary in both duration and degree of pain relief, suggesting modification to needle placement may foster improved pain management. The traditional technique may pose risks to nearby lateral branches of dorsal rami, which are unrelated to facetogenic pain but provide motor innervation to postural muscles. This pilot study evaluates the feasibility of a novel parasagittal technique involving more acute angles from the parasagittal plane and greater cranial-to-caudal angles to better match medial branch trajectories.

Objective: To assess the anatomical feasibility of the proposed parasagittal RFA technique in its ability to achieve proper needle tip alignment and proximity to (< 5mm) medial and distance from ( >5mm) lateral branches of lumbar dorsal rami in a cadaveric model.

Materials and Methods: 14 parasagittal ablation techniques were placed in cadaveric specimens targeting lumbar (L1-L5) medial branches bilaterally, under fluoroscopic guidance by an experienced spine pain interventionalist. Meticulous dissection was then undertaken to assess needle alignment and measure proximities to target nerves (medial and lateral branches) using a digital caliper. Mean needle-to-nerve distances ± standard deviations were calculated in Excel and compared to a standard heat lesion radius (~10x5mm).

Results and Conclusion: The findings of the current study suggest the parasagittal technique is feasible in achieving proper needle placement, as it was successful in 12/14 attempts. The technique achieved close proximity of needle tips to medial branches (0.8 ±1.1mm), while maintaining safe distances from lateral branches (19.2 ± 7.2mm).

Significance: These results anatomically validate the parasagittal technique as a viable alternative to the traditional technique of RFA for facetogenic low back pain. The results warrant further validation in clinical trials to evaluate efficacy as compared to the traditional technique. If successfully implemented, this technique may afford improved medial branch ablation and accompanying pain relief. These outcomes may aid patients to regain lost quality of life, while lowering repeat procedures and the associated healthcare costs.