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