In Reply:—
Critical to the safety of cervical transforaminal injection of steroids is an understanding of the anatomy of the cervical intervertebral foramina and their contents, coupled with disciplined and accurate imaging. We thank both Dr. Gajraj and Drs. Willis and Martin for emphasizing that cervical transforaminal injection should be performed by experienced and well-trained practitioners. Indeed, the radiographic anatomy of the cervical spine is difficult to master. We have all watched talented physicians-in-training get confused by small changes in alignment on the x-ray image caused by positioning or rotation of the neck and stray dangerously off-course during needle placement. Image-guided injection in the cervical spine requires advanced and extended training under the guidance of an experienced practitioner; as we have emphasized before, this is not something that can be mastered through a weekend cadaver course.1
Even with the best technique in skilled hands, minimal changes in needle direction and depth can lead the tip into contact with neural structures. After the needle is in proper position, the volume of the injectate itself can cause painful neural compression. We have emphasized the need to maintain an awake and responsive patient when performing cervical epidural steroid injection via a translaminar route as the only safe means to avoid injury,2and we thank Dr. Gajraj for raising this point because it is equally relevant to any type of neural blockade.
As for Drs. Willis and Martin’s advocating pulsed radiofrequency treatment of the dorsal root ganglion as a superior technique for treating cervical radicular pain, we point out that there is little evidence to support their assertion. Small, randomized trials of conventional radiofrequency treatment (i.e. , resulting in a thermal lesion) of the dorsal root ganglion for the treatment of cervical radicular pain suggest time-limited efficacy.3,4Results from similar trials in patients with lumbosacral radicular pain have been less promising: An initial large observational study suggested significant pain reduction,5but a subsequent randomized trial by the same investigators showed no benefit over placebo.6Pulsed radiofrequency treatment has evolved from the notion that the pain relief that ensues after radiofrequency treatment does not result from actual tissue destruction caused by conventional thermal lesions; rather, it is brought about by the large voltage fluctuations in the area of treatment that induce long-term changes in the dorsal horn of the spinal cord.7The appeal of pulsed radiofrequency treatment is immediately clear: a simple treatment that imparts long-term pain relief without tissue destruction. However, we do not have even a single randomized trial that compares the efficacy of pulsed radiofrequency to any type of control treatment or to conventional radiofrequency treatment. We hope that the evidence will soon appear to support the unbridled zeal of practitioners for this new treatment. We urge those like Drs. Willis and Martin who have extensive experience with these techniques to conduct the randomized trials we need to demonstrate the effectiveness (or lack thereof) of pulsed radiofrequency treatment.
* University of Vermont, Burlington, Vermont. james.rathmell@vtmednet.org
