Injectate Volumes Needed to Reach Specific Landmarks in Lumbar Transforaminal Epidural Injections
Received 1 October 2009; accepted 18 April 2010.
Objectives
To identify the volumes of contrast material needed to reach specific landmarks during lumbar transforaminal epidural injections (L-TFEIs).
Design
Prospective, nonrandomized, observational human study.
Setting
Academic/private pain management practice.
Patients
Sixty-nine patients undergoing L-TFEIs were investigated. Sixty patients were included in this study.
Interventions
L-TFEIs were performed with the use of contrast-enhanced fluoroscopic visualization.
Main Outcome Measurements
After the appropriate spinal needle position was confirmed, up to 5.0 mL of nonionic contrast material was slowly injected. Under biplanar fluoroscopic guidance, contrast volumes were recorded as flow reached specific anatomic landmarks: ipsilateral neural foramen, ipsilateral disks superior and inferior to the injected level, and across the midline of the spinous process.
Results
After 1.1 mL of contrast was injected, 100% of L-TFEIs spread to the medial aspect of the superior pedicle (PED) of the corresponding level of injection. After 2.8 mL of contrast was injected, 95% of L-TFEIs spread to the superior aspect of the superior intervertebral disk (IVD) of the corresponding level of injection. After 3.6 mL of contrast was injected, 95% of L-TFEIs spread to the inferior aspect of the inferior IVD of the corresponding level of injection. After 3 mL of contrast was injected, 88% of L-TFEIs spread to cover both the superior and inferior IVDs of the corresponding level of injection. After 4 mL of contrast was injected, 93% of L-TFEIs spread to cover both the superior and inferior IVDs of the corresponding injection. After 4 ml of contrast was injected, 55% of L-TFEIs spread beyond the midline of the spinous process, but barely.
Conclusion
This study demonstrates injectate volumes needed to reach specific anatomic landmarks in L-TFEIs. A volume of 4.0 mL of injectate reaches both the superior aspect of the superior IVD and the inferior aspect of the inferior IVD 93% of the time.
aOrthopaedic and Spine Specialists, 1855 Powder Mill Road, York, PA 17403†
bDepartment of Physical Medicine and Rehabilitation, UMDNJ-New Jersey Medical School, New York, NY‡
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ABSTRACT