Radiation Dose and Procedure Time for 994 CT-guided Spine Pain Control Procedures

Abstract

Background: Image guidance for spine pain control procedures, including epidural steroid injection, nerve root block, and facet block, can be performed with either computed tomography (CT) or conventional fluoroscopy. CT has the advantage of improved anatomic localization and use of air for contrast; however, there are concerns that CT leads to higher radiation dose and longer procedure time. Objective: To evaluate procedure time and radiation dose for multiple types of spine pain control procedures performed under CT guidance. Study Design: Retrospective evaluation. Setting: Department of radiology in single academic medical center. Methods: Institutional review board approval was obtained. We reviewed CT-guided spine procedures performed over a 12-month period from January 2012 to December 2012. Procedure type, procedure time, and dose-length product were recorded. Patient age and gender were recorded for each case; additionally, demographic and medical history data were obtained for a sub-group of patients. Results: Nine hundred ninety-four studies (performed in 699 patients) were reviewed, including 585 epidural steroid injections, 228 nerve root blocks, and 90 facet blocks. For all studies, procedure time averaged 7:34 ± 5:05, and dose-length product averaged 75 mGy·cm ± 61. Additional medical history (available for 483 patients) revealed high rate of obesity (body mass index [BMI] = 30 ± 6.8, with 76% of patients overweight [BMI > 25] and 42% obese [BMI > 30]), and frequent medical comorbidities (including hypertension [n = 179], diabetes [n = 101], renal failure [n = 30], and heart failure [n = 17]). Limitations: This study was performed retrospectively, and limited to a single institution. Conclusion: These findings add to the growing evidence that CT guidance is a safe and effective technique for epidural steroid injection. These results further demonstrate that other spine intervention procedures, including nerve root block and facet block, can also be performed under CT guidance with short procedure time and reasonable levels of radiation exposure. This approach can be effectively used in a patient population with a high rate of obesity and medical comorbidities. Key words: Epidural steroid injection, nerve root block, facet block, CT-guidance, spine intervention, radiation dose

Counterpoint: Conventional Fluoroscopy-Guided Selective Cervical Nerve Root Block—A Safe, Effective, and Efficient Modality in the Hands of an Experienced Proceduralist

“…11 With safety and efficacy equivalence, this study suggests that CF is the more practical technique by way of potentially reduced procedural times and radiation exposure for both the patient and the proceduralist. 11,21,25,27 Nevertheless, there is a recent publication by Dietrich et al 28 that suggests that radiation exposure for the proceduralist may be higher with CF than with CT/F-guided lumbar procedures. However, the authors indicated that during most CT/F acquisitions, the proceduralist is positioned behind the side of the gantry, while during most acquisitions with CF guidance, the operator is directly adjacent to the patient.…”

“…All fluoroscopy times for CF-SCNRB were recorded at under 2 minutes, with a range of 7-78 seconds. The fluoroscopy time averaged 24.3 seconds per procedure, and radiation exposure based on the time is shown in Table 4 and compared with an average effective dose for CT-guided interventions in a study by Lazarus et al 11 using a conversion factor developed by Huda et al 21…”

“…10 Another disadvantage of CT guidance is added cost to the patient. 11,25 CT guidance has been reported as approximately 0.9 relative value units higher than CF (3.32 for CT for therapy guidance versus 2.41 for CFguided spinal injection). 11 With safety and efficacy equivalence, this study suggests that CF is the more practical technique by way of potentially reduced procedural times and radiation exposure for both the patient and the proceduralist.…”

“…11,25 CT guidance has been reported as approximately 0.9 relative value units higher than CF (3.32 for CT for therapy guidance versus 2.41 for CFguided spinal injection). 11 With safety and efficacy equivalence, this study suggests that CF is the more practical technique by way of potentially reduced procedural times and radiation exposure for both the patient and the proceduralist. 11,21,25,27 Nevertheless, there is a recent publication by Dietrich et al 28 that suggests that radiation exposure for the proceduralist may be higher with CF than with CT/F-guided lumbar procedures.…”

“…2,7,8 However, CT-guided SCNRB may deliver a larger radiation dose to both the patient and proceduralist, 9 with CT fluoroscopy (CT/F) reported to have an increase in the incurred radiation dose over CF by 19-fold in the cervical region (an increase of the incremental dose of 49 uSv). 10 CT guidance is also more costly, 11 may have longer procedural times, 2 and limits real-time assessment of intravascular invasion. 3,4,8 Although sparse, current literature on SCNRB reports various differences in techniques via imaging medium, approach, and needle placement.…”