What is the role of spinal injections during the recovery phase of lumbosacral facet syndrome treatment?

Updated: Nov 19, 2018
  • Author: Gerard A Malanga, MD; Chief Editor: Craig C Young, MD  more...
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Answer

Three fluoroscopically guided spinal injections are often used in the diagnosis and management of Z-joint pain, although their efficacy remains in question. The goal of Z-joint injections is to facilitate a physical therapy program; therefore, their utility is primarily to verify the diagnosis and perhaps reduce pain to make the patient’s physical therapy program more successful. If previous injections were helpful and pain recurs, injections can be repeated; however, they should be limited.

Single injections with a local anesthetic have high false-positive rates (38%). Therefore, when performing any interventional injection, the criterion standard is to use a double- or triple-block paradigm. In a double-block protocol, the patient is given an injection with a short-acting anesthetic (eg, lidocaine) and records the duration of pain relief in a diary. On a follow-up visit (typically 1-2 wk later), a second injection is performed, using an anesthetic with a different duration of action (eg, bupivacaine, which has a longer half-life than lidocaine), and the patient again should chart pain relief in a diary. A patient is diagnosed as having a positive block if they receive pain relief (typically >80%) for both injections for a length of time corresponding to the duration of action of the medication.

For additional diagnostic accuracy, a third block can be performed with saline, although this is rarely performed in clinical practice. The diagnostic reliability of double- and triple-block protocols is clearly superior to that of a single-block protocol; therefore, these should be used before performing an ablation procedure or surgery.

Intra-articular Z-joint injection with corticosteroids and a local anesthetic can also be performed. [24, 25, 26, 27, 28, 29] Typically, this is performed under fluoroscopic guidance with contrast medium. Intra-articular anesthetic injections are considered the most accurate method for diagnosing Z-joint–mediated pain, particularly when performed with a double- or triple-block protocol.

Some have questioned, however, whether intra-articular corticosteroids are as effective in relieving Z-joint–mediated pain as other options, namely RFA of the medial branch of the dorsal ramus. [30, 31, 32] Additionally, injections into the Z-joint are often technically difficult because of joint degeneration and bony overgrowth. The main advantage of intra-articular injections, then, is not so much in its efficacy, but rather that it allows the practitioner to offer a potentially therapeutic injection at the same time as the diagnostic injection (as opposed to RFA, which is preferably performed after a double- or triple-block diagnostic protocol, and thus requires at least 3 separate injections).

Proietti et al aimed to evaluate the effectiveness of facet joints injections in lumbar facet syndrome correlating clinical results to the sagittal contour of the spine. Only patients with thoracolumbar kyphosis and short hyperlordosis (Type I Rossouly classification) showed significant improvement in pain at 3 month follow-up. For other classifications, facet joint injections provided only a temporary pain relief and should be reserved for diagnostic use. [33]

The long-term benefit of intra-articular injection remains controversial, and some studies have reported similar results with either steroids or saline injection.

Complications are rare, although tenderness at the injection site is reported. A few reports have noted spinal block, vasovagal episodes, and chemical meningitis due to puncturing of the dural cuff, but these reports are rare. Recommend that patients withhold medications that promote bleeding, such as NSAIDs, warfarin (Coumadin), and aspirin. However, recent guidelines from the NASS have noted that the risk of MI or stroke in stopping these medications is much greater than the risk of bleeding in the soft tissues of the lumbar spine. Contraindications include bacterial infection, possible pregnancy, bleeding diathesis, and local anesthetic allergy.

Medial branch block for diagnostic purposes has already been described (see Workup, Procedures), and studies have shown it to be effective in this regard; however, controversy remains regarding its use as a therapeutic intervention. Note that such a block also eliminates pain that may be emanating from other structures that are innervated by the medial branch, such as the multifidus or interspinous muscles or the interspinous ligaments.

An alternative to medial branch block denervation was studied by Iwatsuki et al in 21 patients with lumbosacral facet syndrome. [34] These investigators evaluated the use of laser denervation to the dorsal surface of the facet capsule. At 1-year postprocedure, 17 patients (81%) experienced complete or greater than 70% pain reduction, whereas 4 patients (19%) had unsuccessful therapy. [34] Iwatsuki et al suggested that the dorsal surface of the facet capsule might be a more preferable target for facet denervation.

A third intervention involves a medial branch neurotomy through RFA, chemical neurolysis, or cryoneurolysis. Percutaneous radiofrequency neurotomy is a method of denaturing the nerves that innervate the Z-joint through coagulation, thus resulting in more prolonged pain relief. [35, 36] Medial branch neurotomy through RFA has emerged as the standard therapy for facet-mediated low back pain. [20] When performing these procedures, remember that the radiofrequency signal spreads circumferentially from the shaft and not linearly from the tip of the transducer; therefore, the shaft of the transducer must be placed parallel to the medial branch (as opposed to when performing a medial branch block, in which the tip should be aimed at the medial branch because the anesthetic leaves the tip of the needle and not the shaft). Once the axons regenerate, pain often returns.

The therapeutic benefit of this procedure likewise remains controversial [30, 37, 38] ; however, success rates range from 17-90% for periods of 6-12 months. Many of the studies have poor selection criteria, inconsistent techniques, poor outcome measures, and small sample sizes.


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