Description
Discogenic
Low Back Pain
Discogenic low back pain is a common, multifactorial pain syndrome that involves low back pain without radicular symptoms findings, in conjunction with radiologically confirmed degenerative disc disease.
Treatment
Typical treatment includes conservative therapy with physical therapy and medication management, with potential for surgical decompression in more severe cases.
A number of
electrothermal intradiscal procedures have been introduced to treat discogenic low back pain; they rely on various probe designs to introduce radiofrequency energy into the disc. It has
been proposed
that heat-induced denaturation of collagen fibers in the annular lamellae may stabilize the disc and potentially seal annular fissures and that pain reduction may occur through the thermal coagulation of nociceptors in the outer annulus.
Some electrothermal intradiscal procedures
are briefly described
next.
With the intradiscal electrothermal annuloplasty procedure, a navigable catheter with an embedded thermal resistive coil is inserted posterolaterally into the disc annulus or nucleus. Using indirect RF energy, electrothermal heat
is generated
within the thermal resistive coil at a temperature of 90
°
C; the disc material
is heated
for up to 20 minutes. Proposed advantages of indirect electrothermal delivery of RF energy with intradiscal electrothermal annuloplasty include precise temperature feedback and control, and the ability to provide
electrothermocoagulation
to a broader tissue segment than would be allowed with a direct RF needle.
Percutaneous intradiscal radiofrequency thermocoagulation uses direct application of RF energy. With percutaneous intradiscal radiofrequency thermocoagulation, the RF probe
is placed
into the center of the disc, and the device
is activated
for only 90 seconds at a temperature of 70
°
C. The procedure is not designed to coagulate, burn, or ablate tissue. The Radionics RF Disc Catheter System has
been specifically designed
for this purpose.
Intradiscal biacuplasty uses two (2) cooled RF electrodes placed on the posterolateral sides of the intervertebral annulus fibrosus. It
is believed
that, by cooling the
probes,
a larger area may
betreatedthan
could occur with a regular needle probe.
Annuloplasty using a laser-assisted spinal endoscopy kit to coagulate the disc granulation tissue (percutaneous endoscopic laser annuloplasty) has also
been described.
Vertebral body endplates have been proposed as a source of lower back pain, caused by intraosseous nerves. The basivertebral nerve enters the posterior vertebral body and sends branches to the superior and inferior endplates. Vertebrogenic pain, transmitted via the basivertebral nerve, has been purported to occur with endplate damage or degeneration.
Regulatory Status
A variety of RF coagulation devices have
been cleared
for marketing by the United States Food and Drug Administration (U.S. FDA), some of which
are designed
for disc
nucleotomy
. In 2002, the Oratec Nucleotomy Catheter (ORATEC Interventions, Menlo Park, CA, acquired by Smith & Nephew in 2002) was cleared for marketing by FDA through the 510(k) process. The predicate device was the SpineCATH® Intradiscal Catheter, which received FDA clearance for marketing in 1999. The Radionics (a division of Tyco Healthcare group) Radiofrequency Disc Catheter System received marketing clearance by FDA through the 510(k) process in 2000. FDA product code: GEI.
In 2005, the Baylis Pain Management Cooled Probe was also cleared for marketing by FDA through the 510(k) process. It is intended for use 'in conjunction with the Radio Frequency Generator to create radiofrequency lesions in nervous tissue.' FDA product code: GXI.
Note: This evidence review does not address disc nucleoplasty, a technique based on the bipolar RF device (Coblation®; ArthroCare, Austin, TX, acquired by Smith & Nephew, 2014). With the
coblation
system, a bipolar RF device is used to provide lower energy treatment to the intervertebral disc, which is designed to provide tissue removal with minimal thermal damage to collateral tissue. Disc
nucleoplasty
is closer in concept to a laser discectomy in that tissue is removed or ablated
to
provide decompression of a bulging disc. Disc
nucleoplasty
and laser discectomy are considered in evidence review 7.01.93.
Summary of Evidence
For individuals who have discogenic back pain who receive intradiscal electrothermal annuloplasty, the evidence includes a small number of randomized controlled trials (RCTs). Relevant outcomes are symptoms, functional outcomes, quality of life (QOL), and treatment-related morbidity. Two (2) RCTs on intradiscal electrothermal annuloplasty reported conflicting results, with one (1) reporting benefit for intradiscal electrothermal annuloplasty and the other reporting no benefit. Further study in a sham-controlled trial with a representative population of individuals needed. The evidence is insufficient to determine that the technology results in an improvement in the net health outcome.
For individuals who have discogenic back pain who receive intradiscal radiofrequency annuloplasty, the evidence includes two (2) RCTs. Relevant outcomes are symptoms, functional outcomes, QOL, and treatment-related morbidity. Neither RCT found evidence of benefit with the treatment. More sham-controlled trials are needed. The evidence is insufficient to determine that the technology results in an improvement in the net health outcome.
For individuals who have discogenic back pain who receive intradiscal biacuplasty, the evidence includes two (2) industry-sponsored RCTs. Relevant outcomes are symptoms, functional outcomes, QOL, and treatment-related morbidity. One (1) trial reported significant improvements at six (6) months post-treatment, but not at one (1) and three (3) months. The other trial also showed a significant reduction in visual analog scale scores at six (6) months that appeared to continue to the 12 month follow-up; however, it is unclear whether this trial was sufficiently powered. More sham-controlled trials are needed. The evidence is insufficient to determine that the technology results in an improvement in the net health outcome.
For individuals who have vertebrogenic back pain who receive intraosseous ablation of basivertebral nerves, the evidence includes two (2) RCTs (the SMART and INTRACEPT trials). Relevant outcomes are symptoms, functional outcomes, QOL, and treatment-related morbidity. The SMART trial did not find a difference in the Oswestry Disability Index between individuals treated with basivertebral nerve ablation or sham control at three (3) months using an intent-to-treat analysis. Although the per protocol analysis showed a significant difference; results for the per protocol population at 12 months were not significantly different. Additionally, 73% of individuals in this trial crossed over to the active treatment group at 12 months and therefore, long-term comparative data are not available. The INTRACEPT trial found a significant difference in the Oswestry Disability Index and other pain scores between individuals treated with basivertebral nerve ablation and standard care at three (3) months. Comparative data at six (6) months postrandomization showed similar results. However, 92% of individuals initially assigned to standard care elected to cross over to receive early basivertebral nerve ablation, thus, long-term comparative data beyond six (6) months are not available. Additional limitations to this RCT include lack of a sham control. The evidence is insufficient to determine that the technology results in an improvement in the net health outcome.
