Assessing the Agreement Between Radiologic and Clinical Measurements of Lumbar and Cervical Epidural Depths in Patients Undergoing Prone Interlaminar Epidural Steroid Injection

Abstract

Background Fluoroscopy-guided epidural steroid injection (ESI) is commonly performed to treat radicular pain, yet can lead to adverse events if the needle is not advanced with precision.1, 2, 3 Accurate preoperative assessment of the distance from the skin to the epidural space holds the potential for reducing the risks of adverse effects from ESI. It was hypothesized that the distance from the skin to the epidural space as measured on preoperative magnetic resonance imaging (MRI) would agree with the distance traveled by a Touhy needle to reach the epidural space during midline, interlaminar ESI. This study compared the final needle depth measurement at the point of loss of resistance (LOR) from cervical or lumbar ESI to the distance from the skin to the anterior and posterior borders of the epidural space on the associated cervical and lumbar preoperative MRI. Methods This retrospective chart review analyzed the procedure notes, MRI, and demographic data of patients who received a prone, interlaminar ESI at an outpatient chronic pain clinic between June 1, 2013 and June 1, 2015. The following data were collected: BMI, age, gender, intervertebral level of the ESI, and LOR depth. We then measured the distance from the skin surface to the anterior border of the ligamentum flavum (ligamentum flavum depth, or LFD) and dura (dura depth, or DD) on MRI. A total of 335 patients were categorized into the following patient subgroups: age ≥ 65 years, age < 65 years, BMI ≥ 30 kg/m2 (obese), BMI < 30 kg/m2 (non-obese), male, and female. Secondary analyses were then performed to compare the agreement between LOR depth and DD with that between LOR depth and LFD within each patient subgroup. Intra-class correlation coefficient (ICC) and Bland-Altman plot were used to assess the agreement between DD or LFD and LOR depth. Results Data from 335 ESIs were analyzed, including 147 cervical ESIs and 188 lumbar ESIs. Estimated ICC values for the agreement between LOR depth and LFD for all lumbar and cervical measurements were 0.88 (95% CI 0.85 – 0.91) and 0.72 (95% CI 0.64 – 0.79), respectively. Estimated ICC values for the agreement between LOR depth and DD for all lumbar and cervical measurements were 0.86 (95% CI 0.82 – 0.89) and 0.69 (95% CI 0.60 – 0.77), respectively. Conclusions This study assessed the agreement between MRI-derived measurements of epidural depth and those determined clinically. MRI-derived measurements from the skin to the anterior border of the ligamentum flavum, which represents the most posterior aspect of the epidural space, revealed stronger agreement with LOR depths than did measurements to the dura, or the most anterior aspect of the epidural space. These results require further analysis and refinement before supporting clinical application.

Cervical Spondylopathy and Lumbar Intervertebral Disc Herniation Coexist in Free Radical Metabolism and Focus Separation in the Body

“…Therefore, repeated ischemia-reperfusion can be caused locally. During acute and chronic inflammation and ischemia-reperfusion injury, the production of free radicals and lipid peroxidation is increased, resulting in chronic injury of tissues and cells [ 3 ].…”

Correlation of the epidural space measured intraoperatively and estimated by MRI or US: an observational study

“…The agreement between the actual epidural depth and radiologic measurements was assessed to predict the epidural depth. 9 , 10 , 11 , 12 , 21 , 22 , 23 …”

“…Previous studies assessed the agreement between the actual epidural depth and radiologic estimates of epidural depth measured with computed tomography, Magnetic Resonance Imaging (ED/MRI), and Ultrasonography (ED/US) in a variety of patient populations with varying age groups to provide a reliable estimate of the epidural depth. 8 , 9 , 10 , 11 , 12 , 13 …”

“…Former studies assessing the correlation between the actual epidural depth with those measured with ED/US and ED/MRI were retrospective in nature, and the “actual epidural depth” was defined as the epidural needle depth. 8 , 12 , 13 To the best of our knowledge, our study is unique in that we identified the “actual epidural depth” as the “Epidural Depth measured from the surgical site” (ED/AC), and the study is prospectively designed.…”

Relationship between needle depth for lumbar transforaminal epidural injection and patients' height and weight using magnetic resonance imaging

“…However, most calculated the depth of the epidural space by converting the needle length used for the injection and did not provide an exact description of the lumbar level. Further, the majority of studies conducted are limited to interlaminar epidural injection [ 22 ], and there is a lack of research on depth in TFEI [ 14 ]. Commonly used needles for TFEI are too short to approach the target points or target lesions in some patients.…”