Radiation Dose Practice Audit of 6,234 Fluoroscopically-Guided Spinal Injections.

Background: Fluoroscopic imaging guidance is frequently used in performing spinal interventional techniques. Reference level standards are a quality improvement tool to help reduce radiation dose and serve as benchmarks for physicians and their technologists to achieve reasonable radiation exposure while performing fluoroscopically-guided spinal procedures. There are limited data describing radiation dose for musculoskeletal injections - in particular, spinal injections without any published reference standards.

Objective: The purpose of this study is to perform a practice audit of radiation doses of fluoroscopically-guided spinal injections to establish preliminary reference levels as a quality improvement tool for potential use in future radiation reduction measures.

Study Design: Retrospective, observational study.

Settings: An academic-based subspecialty, high volume pain medicine practice.

Methods: A retrospective analysis of 6,234 spinal injections of 9 different types performed by experienced practitioners between January and December 2012 was conducted under an institutional review board's approval with HIPAA compliance and waiver of informed consent. Cumulative radiation dose (in mGy) and exposure time (in seconds) distributions (percentiles) as displayed on the C-arm were calculated per injection for each type of fluoroscopically-guided spinal injection. Confidence intervals for the dose distributions were determined by using bootstrap resampling and were used to determine preliminary reference levels.

Results: Proposed preliminary reference levels of cumulative radiation dose (in mGy) and exposure time (in seconds) for fluoroscopically-guided spinal interventional procedures are provided for lumbar transforaminal (13 mGy, 30 s), cervical transforaminal (6 mGy, 49 s), caudal epidural (12 mGy, 23s), cervical facet injection (3 mGy, 36 s), lumbar facet injection (9 mGy, 20s), interlaminar (13mGy, 39s), lumbar radiofrequency denervation (7 mGy, 17s), lumbar sympathetic block (21 mGy, 39s), cervical medial branch block (2 mGy, 25 s), lumbar medial branch block (4 mGy, 12s) and sacroiliac joint injections (18 mGy, 37s).

Limitations: Study performed at a single subspecialty institution using only one type of C-arm which limits generalizability.

Conclusions: Radiation doses and preliminary reference levels of fluoroscopically-guided interventional spine procedures performed by experienced practitioners are made available without correction for body habitus or field of view, magnification or subtraction techniques or continuous vs pulsed mode. A registry of radiation-dose data for fluoroscopically-guided interventional spine procedures would be the next step to refine this data.

Key Words: Spinal procedures, radiation dose, patient safety.