Effective Dose of CT- and Fluoroscopy-Guided Perineural/Epidural Injections of the Lumbar Spine: A Comparative Study

Abstract

The objective of this study was to compare the effective radiation dose of perineural and epidural injections of the lumbar spine under computed tomography (CT) or fluoroscopic guidance with respect to dose-reduced protocols. We assessed the radiation dose with an Alderson Rando phantom at the lumbar segment L4/5 using 29 thermoluminescence dosimeters. Based on our clinical experience, 4-10 CT scans and 1-min fluoroscopy are appropriate. Effective doses were calculated for CT for a routine lumbar spine protocol and for maximum dose reduction; as well as for fluoroscopy in a continuous and a pulsed mode (3-15 pulses/s). Effective doses under CT guidance were 1.51 mSv for 4 scans and 3.53 mSv for 10 scans using a standard protocol and 0.22 mSv and 0.43 mSv for the low-dose protocol. In continuous mode, the effective doses ranged from 0.43 to 1.25 mSv for 1-3 min of fluoroscopy. Using 1 min of pulsed fluoroscopy, the effective dose was less than 0.1 mSv for 3 pulses/s. A consequent low-dose CT protocol reduces the effective dose compared to a standard lumbar spine protocol by more than 85%. The latter dose might be expected when applying about 1 min of continuous fluoroscopy for guidance. A pulsed mode further reduces the effective dose of fluoroscopy by 80-90%.

Computer-assisted fluoroscopic navigation of percutaneous spinal interventions

“…Fluoroscopic navigation can display multiple X-ray images at the same time reducing radiation exposure while tracing the moving instrument in real time [12]. The success of CT-guidance for percutaneous interventions has been shown in perineural injections [7], pulsed radiofrequency stimulation [9], spinal biopsy [13], percutaneous discectomy [14], kyphoplasty [15], aspiration of spinal cysts [16], and the implantation of pedicle screws [8,11,12,[17][18][19][20]. Foley et al [18] pointed out not only advantages, but also limitations of fluoroscopic navigation and urgently invited to engage in research for other solutions.…”

“…The various spine pathologies therefore demand a pin-point accuracy of diagnostic and therapeutic interventions, which may be difficult in cases with altered anatomy [1][2][3][4][5][6][7]. This particularly applies for percutaneous procedures which are based on accurate needle placement in the pedicles or the disc space [2][3][4][5][6].…”

“…This particularly applies for percutaneous procedures which are based on accurate needle placement in the pedicles or the disc space [2][3][4][5][6]. Intraoperative orientation here is usually based on two-dimensional fluoroscopic imaging [2][3][4][5][6][7][8]. As the needle can only be visualised in one plane, the C-arm position must be changed repeatedly hence, the procedure is prolonged, being more incriminatory for the patient and bearing a higher risk for infection and collateral damage due to repetitive needle correction with higher radiation exposure [7,[9][10][11][12].…”

Reducing Patient Radiation Dose during CT-Guided Procedures: Demonstration in Spinal Injections for Pain

“…Doses for lumbar CTs in adult patients with suspected disk herniation were reduced 35% in this manner without degrading image quality, 10 and experiments in phantoms have predicted substantial dose reductions with lower tube currents during lumbar spine injections. 11 Finally, because CT-guided spinal injections require imaging only short lengths along the scanner axis, switching from helical to axial acquisition modes also can reduce the radiation dose from over-ranging. [12][13][14] This study describes the impact of several steps that were taken in our academic practice to reduce patient radiation during CT-guided injection procedures for spinal pain.…”

MRI-Guided and CT-Guided Cervical Nerve Root Infiltration Therapy: A Cost Comparison

“…The radiation exposure needed for CT fluoroscopic guidance has a potentially damaging effect on patients and personnel [15 -17] and is of importance because many patients often require multiple interventions to achieve lasting pain relief. Hoang et al [39] and Schmid et al [40] documented the average effective dose in CT-guided nerve root infiltrations with the help of a phantom model and calculated average effective dose values of 0.45 mSv and between 0.22 -0.45 mSv. A similar average dose value of 0.48 mSv (approximated) was achieved in our study.…”