1. 2018;21;E477-E482A Retrospective Review of Spinal Radiofrequency Neurotomy Procedures in Patients with Metallic Posterior Spinal Instrumentation – Is it Safe?
   Retrospective Review
   Stephen Ellwood, BS, Peter Shupper, MD, and Andrew Kaufman, MD.

BACKGROUND: Recent studies have shown that medial branch radiofrequency neurotomy (RFN) procedures done at the level of a pedicle screw can increase pedicle screw temperature, and it has been speculated that pedicle screw heating may cause thermal injury. There has been a limited amount of investigation into the real-world safety profile of RFN procedures in patients with pedicle screws.

OBJECTIVES: We aim to demonstrate that the occurrence of serious adverse events is rare for a medial branch RFN procedure completed at a level with metallic spinal hardware when performed according to the Spine Intervention Society practice standards.

STUDY DESIGN: This study involved retrospective chart reviews of every patient who received an RFN procedure for spinal facet joint pain during the 5-year time period from 2012-2016.

SETTING: The research took place within a single university-based interventional pain management center.

METHODS: The study sample included 507 patient charts. Data collection included patient demographics, RF denervation sites at a level with metallic hardware, and all serious RF-related complications that could be attributable to heated metallic hardware. The research team developed medical-chart abstraction criteria for each of the following categorized complications: a) superficial burns, b) deep burns, c) denervation of dorsal ramus, d) denervation of ventral ramus, and e) coagulation of a spinal vascular structure.

RESULTS: Of the 36 patients who met the inclusion criteria for this study, 43.6% were men and 56.4% were women. The mean age was 59.5 years old, with an age range of 25 to 87 years. There were a total of 56 ablations performed at a level with metallic spinal hardware, of which 11 were cervical, 44 were lumbar, and 1 was thoracic . There were zero documented complications found among our patient population in any of the 5 categories of serious complications.

LIMITATIONS: As a retrospective chart review, this study was dependent on the availability and accuracy of medical records. Chart abstraction criteria for each outcome measure were developed by the research team without scientific testing.

CONCLUSIONS: There have been no reported complications attributable to hardware temperature increases when performing medial branch RFNs at the level of a pedicle screw. For safety, it is important to use multiplanar fluoroscopic imaging techniques to ensure that the RFN cannula is not in contact with the pedicle screw.

KEY WORDS: Radiofrequency neurotomy, medial branch nerve ablation, safety, thermal injuries, metallic spinal hardware, pedicle screws, lateral mass screws, cervical facet joints, severe complications, adverse events