Lumbar zygapophyseal or “facet” joint pain accounts for 15-30% of low back pain cases in the adult population. When facet-mediated pain fails to improve with conservative treatment, interventional treatment may be indicated. The COOLIEF Lumbar Cooled Radiofrequency System uses revolutionary cooling technology for lumbar medial branch neurotomy. Many patients may fail standard RF treatments, or have a challenging anatomy. The COOLIEF* Cooled RF System enables placement of a large volume, spherical lesion encompassing the medial branch nerve in one pass, eliminating the need for multiple passes.
The pain mediator in lumbar facet syndrome is the medial branch nerve of the dorsal ramus (MBN), which supplies the facet joints and multifidus muscles at each spinal segment. Thermal MBN lesioning interrupts these afferent nociceptive pathways by applying radiofrequency energy to an electrode placed at the target MBN. In contrast to conventional thermal radiofrequency ablation (T-RFA) wherein the target is heated to 80 degrees C for 90 seconds, cooled radiofrequency ablation (C-RFA) uses a constant flow of ambient water circulated through the electrode via a peristaltic pump to maintain a lower tissue temperature by creating a heat sink, but still allowing neurolysis to occur. By removing heat from tissues immediately adjacent to the electrode tip, a lower lesioning temperature is maintained, resulting in less tissue charring adjacent to the electrode and therefore less tissue impedance. The volume of tissue heated and the resultant thermal lesion size is substantially larger with C-RFA as compared to T-RFA . C-RFA lesions are spherical and project several millimeters beyond the electrode tip as compared to T-RFA, thereby increasing the probability of successful denervation of the target MBN. The lesion characteristics in C-RFA also allow the electrode to be positioned at any angle to make contact with the target neural structure. Together, these make the technique easier to perform.
Each lumbar facet joint has dual innervation, being supplied by 2 medial branch nerves. Each nerve emerges from its intervertebral foramen and enters the posterior compartment of the back by coursing around the neck of the superior articular process. Hugging the neck of the superior articular process, the medial branch passes caudally and slightly dorsally, covered by the mamillo-accessory ligament, hooking medially around the caudal aspect of the root of the superior articular process to enter the multifidus muscle.
Injections are generally avoided in patients with systemic infection or skin infection over puncture site, bleeding disorders or coagulopathy, allergy to local anaesthetics or any of the medications to be administered. Radiofrequency treatment is contraindicated in patients with pacemakers or any other neural implants (spinal cord stimulator, deep brain stimulator)
The COOLIEF Lumbar Cooled Radiofrequency System uses revolutionary cooling technology for lumbar medial branch neurotomy. Many patients may fail standard RF treatments, or have a challenging anatomy. The COOLIEF* Cooled RF System enables placement of a large volume, spherical lesion encompassing the medial branch nerve in one pass, eliminating the need for multiple passes.
The procedure is usually done on an outpatient basis. The procedure is performed under fluoroscopic guidance to ensure the accuracy of needle placement. Patients need to be aware that the outcome of the procedure is variable and they may not receive the desired benefits. Similarly, they must be aware of the transient nature of the therapeutic benefits and that there may need repeated injections.
Radiofrequency treatment is a two-step procedure. The first step is diagnostic, involving an injection of local anaesthetic around the medial branches innervating the relevant facet joints. Patients who experience good pain relief following diagnostic injections are offered radiofrequency denervation treatment. This involves creating a heat lesion around the nerves carrying painful impulses from the facet joints. Successful treatment can result in pain relief lasting 6 months to 2 years.
Radiofrequency treatment is performed under local anaesthesia and patient cooperation is very important in identifying the target nerves. The treatment does not work immediately and can take 4 to 6 weeks to kick in.
Complications are rare, particularly if injections are performed using a precise needle-positioning technique. Possible complications include spondylodiscitis, septic arthritis, and reaction to the injectates. Septic arthritis can be avoided with appropriate aseptic precautions. Severe allergic reactions to local anaesthetics are uncommon. Post-procedural pain flare-up is not uncommon and may be treated with painkillers. Neurological complications including paraesthesias, numbness, and paralysis have been described but are extremely rare. Radiofrequency treatment can cause patchy numbness of the overlying skin. Infections including epidural abscess and chemical meningitis can occur but the incidence is very low as the procedure is performed under strict aseptic conditions.