Distribution patterns of transforaminal injections in the cervical spine evaluated by multi-slice computed tomography

Abstract

Transforaminal injections are sometimes used for the diagnosis and treatment of painful conditions in the lumbar and to a lesser degree in the cervical spine. The technique is most often used when investigating/treating radiculopathy caused by degenerative disease. But how selective are the nerve root blocks? What possible structures other than the intended nerve root are affected from such injections? This study was undertaken in order to try to answer these questions, as no study focusing on the possible spread from the transforaminal selective nerve root blocks in the cervical spine has been performed earlier. In three groups of patients, each group including three patients, we injected three different volumes (0.6, 1.1 and 1.7 ml) with a transforaminal technique in the cervical spine. In all the injections, a small amount of contrast media was added. The spread of the injections were then investigated using multi-slice computed tomography with reconstructions. The imaging revealed a possible effect on other nerve roots than the intended ones when a larger volume was used for the root blocks. The spread was related to the injected volume as well as to local anatomy (size of foraminal area). In this study, only 0.6-ml injections could be accepted for being selective enough for diagnostic investigations.

Occipital Nerve Pulsed Radiofrequency Treatment: A Multi-Center Study Evaluating Predictors of Outcome

“…The correlation between lower block volume and success rate is likely related to increased diagnostic specificity and is similar to studies evaluating other diagnostic nerve blocks [28–30]. The observation that more cycles of PRF were associated with better outcomes is consistent with some [31], but not all [22], preclinical studies that found greater anti‐allodynic effects with increased PRF duration.…”

Randomized Study Assessing the Accuracy of Cervical Facet Joint Nerve (Medial Branch) Blocks Using Different Injectate Volumes

“…There are several limitations that should be addressed to place these results in context. First, although CT scans have previously been used as the definitive standard for evaluating the accuracy of fluoroscopically guided nerve blocks, 18,40 they are limited by their inability to visualize nervous tissue. Despite potential variability in nerve location, 33,41 this was deemed acceptable because the target sites are almost always the same for fluoroscopically guided MBB, [2][3][4]17,27 which are subject to the same limitations.…”

The diagnostic utility and cost-effectiveness of selective nerve root blocks in patients considered for lumbar decompression surgery: a systematic review and economic model

“…Of the five studies 28,[38][39][40][41] included in our review, three 28,39,41 were also included in the updated Datta et al review. 62 Of the remaining 13 included in the Datta et al review 62 but excluded from our study, three studies [64][65][66] were excluded as they focused on cervical spine injections (see Table 21). Six studies 27,[67][68][69][70][71] were excluded from our review because it was impossible to reconstruct sensitivity and specificity or 2 × 2 tables of index test and reference standard results.…”