A simple approach for ultrasound-guided pararadicular injections in the sacral spine: a pilot computer tomography controlled cadaver study.

Abstract

Injection therapies play an increasingly decisive role in the treatment of lower back pain. Cumulative studies couldshow the benefits of ultrasound-guided instillation procedures in the cervical and lumbar spine. We conducted this study toprovide a new simple sonographic approach for pararadicular injections of the sacral spinal nerves and to prove the feasibilityand accuracy by means of CT and anatomic dissection. Eight ultrasound-guided injections at fourdifferent levels of the sacral spine on a human ethanol-glycerol-embalmed cadaver (S1-S4) were performed. By means ofsonography the sacral foramina were identified and the spinal needles were advanced in "in-plane technique" to the medialmargin of the respective sacral foramen. Subsequently a solution of blue dye and contrast agent were injected. Then CT scansand anatomic dissection of the cadaver were performed to verify the correct placement of the needle tips and to visualize thedispersion of the injected solution in the respective compartment. Altogether a 100% success rate for a correct injectioncould be achieved. CT examination confirmed the correct placement of every needle tip within the intended compartment.Also, the anatomic dissections affirmed the appropriate needle positioning. Moreover, the blue dye dispersion was seen in thecorrect compartments and around the targeted spinal nerves. Although this study was only performed on cadavericmodels, this new sonographic approach for pararadicular injections in the sacral spine allows an easy, precise and unerringneedle placement within the dorsal sacral foramen.