Fig. 6.1
PET/CT scan, coronal reconstruction illustrating a right C4–C5 facet joint which is FDG avid
Standard and dynamic X-rays define normal and pathological curves of the spine. Spine and facet joint have a higher chance of suffering in locations where curves change physiologically; as far as upper spine is involved, these locations include low cervical level and cervico-thoracic junction. In case of pathologic spinal curves (scoliosis, listhesis, inversion of lordosis or hyperkyphosis), X-rays may reveal the area of potential maximum pressure and pain along with findings suggestive of arthritis such as osteosclerosis and osteophytes. On the other hand, MRI and CT scan may additionally reveal ligament hypertrophy, subchondral hyper-pressure and intra-articular effusion [1]. Any imaging examination has to be correlated with data from clinical examination in order to select the area of potential painful source and additionally exclude other causes of suffering (vertebral fracture, disc herniation-degeneration, etc).
Once diagnosis of a painful facet joint is confirmed, the first therapeutic approach includes a 4–6-week course of standard conservative treatment (including medication and physiotherapy); once and if this course fails, interventional treatments have to be considered. A faster approach circumventing medication treatment might be used in cases of intolerance to NSAIDs.
6.2 Steroid Injections
Under imaging guidance and local sterility measures, a 22 G spinal needle is advanced intra-articularly inside the facet joint of interest. Contrast medium injection with subsequent joint opacification will verify correct needle placement inside the joint. Depending on an operator’s preference, a mixture containing steroid with local anaesthetic or normal saline is injected. This injection is not considered a selective pain bloc, but provides information and identifies the facet joint as a potential pain source due to three different responses:
During the injection (pain is usually reproduced in the symptomatic area)
During the anaesthetic period (pain reduction or diminishment due to the local anaesthetic)
During the follow-up period (pain reduction or diminishment due to the anti-inflammatory effect of steroid)
As stated previously, intra-articular facet joint steroid injections should not be considered facet specific, for two main reasons:
- 1.
The volume of injected products is higher than the joint’s capacity and a diffusion of anaesthesia has to be considered probable (epidural or periradicular); pain reduction post injection could be related to this extra-articular diffusion as well [3].
- 2.
A general effect of steroid is usually observed in the days following the injection and patients often report to be better in other arthritis-related locations after a facet injection.
Prior to radiofrequency denervation, according to most guidelines, two specific nerve blocs are mandatory [4–6]. These are performed by accessing the median branch, which transfers the sensory stimulus of the posterior articulation at each level of spine. It can be accessed by needle under fluoroscopic or CT guidance for diagnostic or therapeutic purposes (Fig. 6.2). Median branch block, in contrast to facet injection, should be considered a selective pain bloc; with this technique a small quantity (0.2–0.3 cc) of local anaesthetic—in order to avoid potential liquid diffusion—is performed under imaging guidance at the level of the median nerve.
Fig. 6.2
Lateral fluoroscopy view: yellow lines indicate the location of median nerve branches at C3–C4 level
As far as the cervical spine is concerned, the access for a median branch block is posterolateral and ascending to the antero-lateral part of the joint (Fig. 6.3) [7]. Under strict sterile condition, a 22 G spinal needle is advanced to the define target with our without skin anaesthesia (paraspinal muscle anaesthesia on the way of the needle is usually not performed to diminish false positive response due to muscular relapse). The anaesthetic is injected gently after imaging control proving good positioning of needle and needle tip assuming a bone contact in the defined area. Patient is clinically evaluated before and after the selective pain bloc to define diminishing of pain and comfort. Generally, pain bloc is considered positive if the pain is diminishing during the anaesthetic period at least four VAS graduations. According to the life expectancy of the anaesthetic, the patient should inform when the pain is returning at a specific level. If two selective blocs performed at least 48 h apart are positive, radiofrequency treatment is indicated.
