Editor-in-Chief: Kenneth D. Candido, MD
BACKGROUND: Recent literature has demonstrated that the contralateral oblique (CLO) view provides a more reliable angle in determining needle depth when compared to the lateral view during cervical interlaminar injections. Despite the utilization of CLO safety views, contrast patterns, and loss-of-resistance techniques, inherent risk of injury still remains. Additional safety measures must be assessed to provide clinicians with further safeguards to prevent procedural complications.
OBJECTIVE: The purpose of our study is to provide a reliable method of gauging needle depth insertion during cervical interlaminar injections by comparing the distance from the skin to the epidural space when measured on magnetic resonance imaging (MRI) and when measured intraoperatively.
METHODS: The study sample included 45 patients with cervical radiculopathy or cervical spinal stenosis. The distance from the skin to the epidural space was measured on cervical spine MRI and with the spinal needle intraoperatively. Primary analysis included the correlation between these distances, and whether differences in depth were influenced by injection level, needle tip location, or body mass index (BMI).
RESULTS: A significant correlation (r = .975, P < .001) with an average difference of .03 mm (standard deviation, 2.99 mm) was found between MRI and procedural measurements. Neither injection level nor BMI had a significant influence on the difference in depth.
CONCLUSION: When combined with traditional safety techniques, obtaining preprocedural MRI depth measurements can provide a reliable method in predicting the true needle depth to safely enter the epidural space. Because the majority of patients undergoing interlaminar cervical epidural steroid injections will have already obtained MRI, measuring the distance preprocedurally is a simple and practical method for physicians to implement.
KEY WORDS: Cervical, fluoroscopy, radiculopathy, injection, contra-lateral oblique, contrast, safety, complications, spinal stenosis, radiation, interlaminar