Pain Points

Discogenic pain is one of the most debated diagnoses in spine care. The patient has chronic low back pain, the MRI shows a "dark disc" or a "high-intensity zone," and the physician is unsure whether the disc is the source of the pain.

The 22G RF needle is often used to treat discogenic pain, but the results are inconsistent. Some patients get excellent relief, while others get no relief at all. The inconsistency is frustrating for the patient and the physician.

The problem is that discogenic pain is not a single entity. It can be caused by annular tears, inflammatory mediators, nerve ingrowth, or mechanical instability. Each of these causes requires a different treatment approach.

Other pain points include:

The operator may not perform a discography before the RF procedure. The discography is essential for confirming that the disc is the source of the pain.

The operator may not use the correct RF technique. Thermal ablation, pulsed RF, and biacuplasty are different techniques with different mechanisms of action.

The operator may not have the right needle. The needle must have the appropriate exposed tip length and insulation for the target.

Principle

Discogenic pain arises from the innervation of the annulus fibrosus. The outer third of the annulus is innervated by the sinuvertebral nerve and the gray ramus communicans. When the annulus is damaged, inflammatory mediators and nerve ingrowth can sensitize these nerves, causing pain.

RF energy can modulate or ablate these nerves. Thermal RF creates a lesion in the annulus, interrupting the pain signal. Pulsed RF modulates the nerve function, reducing the inflammatory response. Biacuplasty creates a bipolar lesion in the posterior annulus, targeting the pain fibers.

The physics is the same ionic friction. The RF energy heats the tissue around the tip, creating a lesion or modulating the nerve function. The key is the placement and the technique.

Device Types

Several types of 22G disposable RF needles are available for discogenic pain procedures.

22G Intradiscal Thermal Needle​ is used for thermal annuloplasty. The needle is placed in the disc, and RF energy is delivered to the posterior annulus. The heat coagulates the pain fibers and shrinks the annular tissue.

22G Pulsed RF Disc Needle​ is used for pulsed RF of the disc. The needle delivers pulsed RF energy to the annulus, modulating the nerve function without destroying the tissue.

22G Biacuplasty Bipolar Needle​ is used for biacuplasty. The needle has two electrodes that create a bipolar lesion in the posterior annulus. The lesion targets the pain fibers while sparing the nucleus.

22G Racz-Type Catheter Needle​ is used for targeted delivery of RF energy to the annular tear. The catheter is advanced through the needle to the target, and RF energy is delivered.

22G Diagnostic Provocation Needle​ is used for discography. The needle is placed in the disc, and contrast is injected to reproduce the pain. The provocation confirms that the disc is the source of the pain.

Hands-on Guide

The following steps represent best practice for using a 22G disposable RF needle for discogenic pain.

Step 1: Perform Discography First.​ The operator should perform a discography to confirm that the disc is the source of the pain. The discography should reproduce the patient's typical pain at a low pressure and at a low volume.

Step 2: Confirm the Annular Tear.​ The operator should confirm the annular tear on the discography image. The contrast should leak through the tear, confirming the annular disruption.

Step 3: Select the Appropriate Technique.​ The operator should select the appropriate technique based on the clinical scenario. Thermal annuloplasty for a contained tear, pulsed RF for inflammatory pain, and biacuplasty for posterior annular pain.

Step 4: Place the Needle in the Target.​ The operator should place the needle in the target using imaging guidance. The tip should be positioned in the posterior annulus for thermal and biacuplasty, or in the nucleus for pulsed RF.

Step 5: Deliver RF Energy.​ The operator should deliver RF energy at the appropriate settings for the technique. The operator should monitor the temperature and impedance throughout the procedure.

Step 6: Document the Procedure.​ The operator should document the discography results, the technique, the settings, and the patient's response.

Field Experience

Centers that use discography before RF report better patient selection and higher success rates. The discography confirms that the disc is the source of the pain, reducing the risk of a failed procedure.

One important lesson from the field: the discography is not always positive. Some patients with discogenic pain do not have a positive discography. These patients are unlikely to respond to RF.

Another lesson: the technique matters. Thermal annuloplasty is more effective for contained tears, while pulsed RF is more effective for inflammatory pain. The operator should choose the technique based on the clinical scenario.

Summary

Discogenic pain is a complex condition that requires a precise diagnosis and a targeted treatment. The 22G RF needle provides a minimally invasive tool for modulating or ablating the pain fibers in the annulus. The key is the patient selection and the technique.

The result is a procedure that is effective in the right patients and avoided in the wrong patients. The 22G needle is a precision instrument, and precision instruments require precision indications.

Outlook and Recommendations

The future of discogenic pain RF will be shaped by advances in diagnosis and treatment.

Molecular Biomarkers.​ Future protocols will use molecular biomarkers of disc degeneration, such as inflammatory cytokines, to identify patients who are likely to respond to RF.

Stimulation-Guided RF.​ Future needles will incorporate stimulation electrodes that can map the pain fibers in the annulus. The operator can identify the exact location of the pain fibers and deliver RF energy precisely.

Combination Therapy.​ RF will be combined with other treatments, such as stem cell therapy or platelet-rich plasma, to enhance the healing of the disc.

For procurement, the recommendation is to include a discography protocol in the training bundle. The protocol should specify the contrast volume, the pressure, and the interpretation criteria.