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Indications & Patient Selection
Indications
- Vertebrogenic chronic low back pain due to Modic type I or II endplate changes on lumbar MRI
- Chronic LBP ≥6 months duration with VAS ≥4
- Modic changes at L3–S1 confirmed on MRI ≤6 months old
- Failed conservative therapy: physical therapy, NSAIDs, and spinal injections (facet, SI joint, epidural)
- Typical levels treated: L3-4, L4-5, L5-S1; 1–3 levels most common
- Also effective for adjacent-level vertebrogenic pain after prior lumbar fusion
Contraindications
- Modic III changes only (sclerotic end plates — no inflammatory component, no pain response expected)
- Osteoporosis (T-score < −2.5 at treatment level) — increased fracture risk through ablation zone
- Active spinal infection
- Uncorrectable coagulopathy
- Prior spinal fusion at the target level
- Primary pain source identified as discogenic, facetogenic, or SI joint (must rule out before proceeding)
Modic Change Classification (MRI Criteria)
| Type | T1 Signal | T2 Signal | Pathology | Pain Response |
|---|---|---|---|---|
| Type I | Hypointense (dark) | Hyperintense (bright) | Active inflammation / subchondral edema | Responds; may respond slightly better |
| Type II | Hyperintense (bright) | Isointense | Fatty marrow conversion | Responds; acceptable indication per labeling |
| Type III | Hypointense | Hypointense | Sclerotic / end-stage degeneration | No response; contraindication |
Required Workup
- MRI lumbar spine ≤6 months old confirming Modic I or II at target level(s) — review T1 and T2 sequences carefully
- Baseline VAS and Oswestry Disability Index (ODI) scores documented
- X-ray or DEXA to assess bone quality; exclude osteoporosis at treatment level
- Clinical exam excluding radiculopathy as primary complaint
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Pre-Procedure Checklist
Confirm Modic type on MRI. Review T1 and T2 sequences immediately before the procedure. Identify all target levels. Mark pedicle targets bilaterally on the pre-procedure images. Do not proceed without verified Modic I or II changes.
Intracept system (Relievant Medsystems) confirmed available. Verify Intracept bipolar RF probe, curved introducer cannula, and proprietary RF generator (Intracept console) are on hand. This is a proprietary system — standard RFA generators cannot be substituted.
Access instrumentation ready. 11G Jamshidi-type bone access trocar and 8G curved working cannula. Confirm sizes match the Intracept system specifications.
Imaging guidance confirmed. Biplanar fluoroscopy (preferred) or CT-fluoroscopy available. Confirm both AP and lateral views are achievable for the target levels before beginning.
Anesthesia: GA or deep sedation required. Bone drilling and pedicle access are painful — local anesthesia alone is insufficient. Coordinate with anesthesia team before scheduling.
Antibiotics: Cefazolin 1g IV. Administer within 60 minutes before skin incision. Bone procedure carries infection risk (diskitis, osteomyelitis). Document administration time.
Patient positioning: Prone. Confirm adequate prone positioning is tolerated by the patient. Pad pressure points. Ensure abdomen is free to reduce venous congestion.
Bone quality assessment. Review DEXA or X-ray. T-score < −2.5 at treatment level is a contraindication due to fracture risk. If not available and osteoporosis is suspected, obtain DEXA before proceeding.
Consent discussion. Review: post-procedure pain flare (20–40%, 2–4 weeks), fracture risk, neurologic injury (pedicle breach), infection (<0.5%), incomplete ablation requiring second procedure, and that improvement typically develops over 4–8 weeks.
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Relevant Anatomy
Basivertebral Nerve (BVN)
- Sensory nerve located within the posterior vertebral body; transmits pain signals from the vertebral endplates
- Enters the vertebral body through the basivertebral foramen (BVF) — a midline posterior channel that also carries the basivertebral veins
- Innervates the superior and inferior endplates of the vertebral body
- Nerve density increases in damaged and degenerated endplates — sensitization underlies vertebrogenic pain in Modic I/II changes
- Target for ablation: posterior one-third of the vertebral body, centered on the BVF
Basivertebral Foramen & Access Route
- BVF location: midline, posterior vertebral body at mid-height of the vertebra — visible as a notch or indentation on lateral fluoroscopy
- Transpedicular approach: the trocar enters through the pedicle (ipsilateral) to reach the posterior vertebral body center — pedicle acts as a bony "tunnel" protecting neural structures
- Bilateral pedicle access (right and left) provides better BVF coverage; curved cannula deflects to midline from each side
- Ablation zone at 85°C × 15 minutes creates an ovoid zone encompassing the BVF and surrounding subchondral bone
- Post-ablation MRI: oval signal change within the vertebral body (STIR/T1/T2) confirms ablation zone
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Technique
Default RadCall approach · share your own below
Supplies
Intracept bipolar RF probe (Relievant)
Intracept curved introducer cannula
Intracept RF generator console
11G Jamshidi bone access trocar
8G curved working cannula
Biplanar fluoroscopy
Cefazolin 1g IV
GA or deep sedation
ChloraPrep
Sterile drape
Sterile dressing
Transpedicular BVN Ablation — Standard Technique
Steps
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Positioning & planning
Patient prone on fluoroscopy table. Set up biplanar fluoroscopy with AP and lateral views available. Review pre-procedure MRI to confirm Modic I/II levels. Mark pedicle targets bilaterally for each treatment level (most common: L3-4, L4-5, L5-S1).
▶ Unipedicular vs bipedicular approach planning
Unipedicular approach: AP fluoroscopic planning confirms pedicle target — used for single-level ablation when bilateral access is not required.
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AP "Owl Eye" targeting
Obtain AP fluoroscopy. Rotate C-arm to align with the target endplate (square the disc space). Both pedicles appear as oval "owl eye" targets. Align the 11G Jamshidi trocar with the center of the ipsilateral pedicle using coaxial technique — the trocar tip should project within the pedicle shadow throughout advancement.
▶ AP “owl eye” fluoroscopy confirmation
AP “owl eye” view: pedicle seen en face — advance trocar to center of pedicle without crossing medial wall; lateral wall contact is acceptable.
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Transpedicular trocar advancement
Advance the 11G trocar through the pedicle cortex using a mallet if needed — confirm on AP that the trocar remains within the pedicle oval. Switch to lateral view: advance to the posterior quarter (25%) of the vertebral body depth. Do not cross the midline or advance to the anterior half on lateral view at this stage.
▶ Pedicular trocar advancement to basivertebral foramen
Transpedicular access: trocar advanced through pedicle to posterior vertebral body — lateral view confirms trajectory before crossing the posterior cortex.
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Insert curved working cannula
Through the Jamshidi trocar, insert the 8G curved working cannula. The curve deflects the cannula toward the midline basivertebral foramen. Advance until the tip reaches the center of the vertebral body on lateral view (approximately 50% depth). Confirm on AP view: tip should be at or near midline.
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Confirm BVF position
AP view: cannula tip at midline = correct position at basivertebral foramen. Lateral view: tip at center of vertebral body (slightly posterior to center) = correct. If tip is off midline on AP, the cannula has not reached the BVF — reassess pedicle entry point (may need to re-enter more medially).
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Insert Intracept RF probe & ablate
Insert the Intracept bipolar RF probe through the curved cannula to the confirmed BVF position. Connect to Intracept RF generator console. Ablation parameters: 85°C × 15 minutes per level. The generator runs a proprietary ablation cycle — do not interrupt. Single 15-minute cycle achieves adequate ablation in standard anatomy.
▶ Intracept RF probe deployed — active ablation
Intracept RF probe deployed at basivertebral foramen — AP view confirms probe position at midline; ablation creates a 10 mm zone targeting BVN terminals.
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Contralateral pedicle (bilateral approach)
Repeat steps 2–6 through the contralateral pedicle for bilateral BVF coverage. Bilateral approach improves ablation zone coverage of the entire BVF. If a single curved cannula definitively reaches the midline with adequate coverage confirmed, contralateral access may be deferred — but bilateral is preferred.
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Repeat at additional levels
For each additional Modic level (up to 3 levels in a single session), repeat the bilateral transpedicular approach. Confirm probe position before each ablation cycle. Document treated levels.
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Post-procedure confirmation & closure
Obtain post-procedure CT (or final fluoroscopy) to confirm probe placement and exclude cortical breach. Remove cannulas and trocars. Apply sterile dressings. Recover 1–2 hours. Same-day mobilization — no bed rest required.
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Fluoroscopic Landmarks
AP View — "Owl Eye" Pedicle Targeting
- Both pedicles appear as oval or circular targets ("owl eyes") in AP view when the endplate is squared with the fluoroscopy beam
- Advance trocar coaxially within the ipsilateral pedicle oval — tip should remain inside the pedicle circle throughout advancement
- Trocar medial wall breach (tip crosses the medial pedicle cortex) → risk of epidural hematoma; stop and recheck
- Final curved cannula tip: at or crossing midline on AP = correct BVF position
- Tip lateral to midline on AP = has not reached BVF; curved cannula entry point too lateral
Lateral View — Depth Control
- Advance trocar to posterior 25% of vertebral body depth on lateral view before inserting curved cannula
- Insert curved cannula through trocar; advance to center of the vertebral body (50% depth) on lateral — this is the BVF location
- Correct lateral position: tip slightly posterior to true center (posterior 40–50% of body depth)
- Stop immediately if trocar or cannula approaches the anterior 25% on lateral — risk of anterior cortex breach
- Anterior cortex breach = potential injury to great vessels or viscera — abort and obtain CT
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Troubleshooting
Problem
Curved cannula will not redirect to midline
Likely cause: Pedicle entry point is too lateral — the curved cannula's trajectory from a lateral starting position cannot reach the midline BVF even with full deflection.
Next step: Remove the cannula. Re-enter the pedicle more medially (aim for the medial third of the pedicle oval on AP view). Re-insert and confirm midline tip position on AP before proceeding to ablation.
Problem
Cortical breach detected
Likely cause: Over-advancement of trocar or cannula beyond intended depth; excessive lateral angulation causing pedicle wall breach.
Next step: Obtain CT immediately to characterize the breach location. Minor posterior cortex breach without neural injury may allow cautious continuation. Anterior cortex breach or medial pedicle breach with neurologic concern: abort procedure. Neurologic exam post-procedure mandatory.
Problem
Post-procedure worsening pain (acute)
Likely cause: Post-ablation inflammatory response — very common (20–40%). The ablation zone triggers a local inflammatory cascade before healing. This is expected and typically peaks at 1–2 weeks then resolves by 2–4 weeks.
Next step: Counsel patient pre-procedure that this is expected. Manage with NSAIDs (if not contraindicated). If severe or associated with neurologic symptoms, obtain MRI to exclude hematoma or infection. Most cases self-resolve within 4 weeks.
Problem
Wrong levels selected / Modic type mismatch
Likely cause: Modic levels confirmed on old imaging not repeated; Modic type misidentified (Type III treated as Type II); confusion between adjacent vertebrae.
Next step: Always re-examine the MRI T1 and T2 sequences immediately before the procedure. Confirm level by counting from S1 on both AP fluoroscopy and the MRI. Type III (hypointense on both T1 and T2) will not respond — do not treat. If any uncertainty about level, obtain intraoperative CT correlation before trocar placement.
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Complications
Expected / Common
- Post-procedure pain flare (20–40%) — transient worsening of LBP for 2–4 weeks post-ablation; inflammatory response to ablation zone; counsel patient before discharge; manage with NSAIDs; resolves spontaneously
- Minor access site discomfort — pedicle entry site soreness; expected; resolves in days
Serious / Rare
- Vertebral fracture through ablation zone — very rare; risk increased with osteoporosis; screen with DEXA pre-procedure; T-score < −2.5 is contraindication
- Neurologic injury — rare with proper technique; lateral pedicle breach can cause epidural hematoma or nerve root injury; medial breach can injure thecal sac; confirm AP pedicle position throughout trocar advancement
- Infection (diskitis / vertebral osteomyelitis) — incidence <0.5%; prophylaxis with cefazolin 1g IV + strict sterile technique; presentation: fever, worsening pain, elevated inflammatory markers; workup with MRI spine with contrast; treat with antibiotics ± surgical drainage if abscess
- Incomplete ablation — suboptimal Modic change coverage; may require second-stage procedure; ensure bilateral pedicle access and midline cannula tip confirmation before each ablation
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Critical Pearls
✶
Patient selection is EVERYTHING. Only Modic I or II endplate changes respond to BVN ablation. No Modic changes (or only Modic III) = no benefit. This is not a procedure for nonspecific LBP. Confirm on MRI T1 and T2 sequences immediately before the procedure — do not rely on outside reads alone.
✶
Level-1 trial evidence supports this procedure. The SMART trial (Fischgrund et al.) and the INTRACEPT trial (Khalil et al.) both demonstrated statistically significant and clinically meaningful improvements in ODI and VAS versus sham/conservative care. INTRACEPT was stopped early by the data safety monitoring board due to overwhelming benefit in the treatment arm. 75% responder rate (≥50% VAS reduction) at 1 year vs. 33% sham; sustained at 5 years.
✶
Modic I may respond slightly better than Modic II in some subgroup analyses, but both are acceptable indications per Relievant Medsystems labeling. Do not exclude Modic II patients from consideration.
✶
Bilateral pedicle approach gives better BVF coverage than unilateral. The curved cannula from a single pedicle may not fully encompass the BVF. Bilateral entry ensures the ablation zone covers the midline foramen from both sides. Plan for bilateral access at each level from the start.
✶
Ablation parameters are fixed by the system. The Intracept generator delivers 85°C × 15 minutes — this is the validated protocol from the pivotal trials. A single 15-minute cycle achieves adequate ablation in standard anatomy. Do not try to abbreviate the cycle or substitute a generic RF generator.
✶
Works well for adjacent-level vertebrogenic pain after lumbar fusion. Patients who have undergone prior lumbar fusion and develop Modic changes at adjacent levels are good candidates. The fused segment is not treated; the adjacent unfused level is targeted. Confirm the adjacent level is not included in the fusion construct before planning access.
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References
Citations
- Prologo JD, Ray CE Jr., eds. Advanced Pain Management in Interventional Radiology: A Case-Based Approach. Thieme; 2024. Ch. 30 (Nguyen AML, Nguyen DTD).
- Fischgrund JS, Rhyne A, Franke J, et al. Intraosseous basivertebral nerve ablation for the treatment of chronic low back pain: a prospective randomized double-blind sham-controlled multi-center study. Eur Spine J. 2018;27(5):1146–1156.
- Khalil JG, Smuck M, Koreckij T, et al.; INTRACEPT Trial Investigators. A prospective, randomized, multicenter study of intraosseous basivertebral nerve ablation for the treatment of chronic low back pain. Spine J. 2019;19(10):1620–1632.
- Fischgrund JS, Rhyne A, Franke J, et al. Randomized controlled trial of basivertebral nerve ablation for the treatment of chronic low back pain. Spine J. 2018;18(10):1753–1765.
- Modic MT, Masaryk TJ, Ross JS, Carter JR. Imaging of degenerative disk disease. Radiology. 1988;168(1):177–186.
- Lotz JC, Fields AJ, Liebenberg EC. The role of the vertebral end plate in low back pain. Global Spine J. 2013;3(3):153–164.
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References & Resources
Primary sources · Key data · Related procedures
Key Guidelines
- SIR Standards of Practice for Thermal Ablation
- ACR Appropriateness Criteria for Low Back Pain
Primary References
- Fischgrund JS et al. Randomized controlled trial comparing radiofrequency ablation of the basivertebral nerve to conservative medical management for treatment of chronic low back pain. Spine J. 2018;18(10):1794-1802.
- Prologo JD, Ray CE Jr., eds. Advanced Pain Management in Interventional Radiology. Thieme; 2024. Ch. 30: Basivertebral Nerve Ablation.
- Becker S et al. Basi-Vertebral nerve ablation in chronic vertebrogenic low back pain. Acta Neurochir Suppl. 2019;125:179-183.