New Horizons and Hurdles in Interventional Pain Management

Educational Objectives

The goal of this program is to improve delivery of interventional pain management. After hearing and assimilating this program, the clinician will be better able to:

1. Analyze evidence-based data supporting the use of various forms of spinal cord stimulation (SCS) for management of chronic back and joint pain.
2. Consider microdosing as an alternative approach to standard intrathecal therapy for management of chronic pain.
3. Explore use of minimally-invasive surgical options for management of chronic back and sacroiliac joint pain.

Summary

Advanced interventional procedures: radiofrequency ablation (RFA) — modalities include thermal (most commonly used), cooled, and pulsed; RFA preferentially destroys pain-carrying A-delta and C fibers; however, changes in insurance coverage affect its availability; spinal cord stimulation (SCS) — involves placing electrodes in the epidural space to relieve pain; in 1989, SCS received its first Food and Drug Administration (FDA) clearance for treating chronic pain resulting from nerve damage in the trunk, arms, or lower extremities (LEs); intrathecal (pump) therapy — initially used for terminal cancer pain and subsequently expanded to noncancer pain; remains one of the most effective therapies for refractory bone pain secondary to metastatic cancer; Stearns et al (2020) reported that intrathecal therapy improves patient quality of life (QOL) and extends longevity following cancer diagnosis

Recent advances in neurostimulation: high-frequency SCS — Kapural et al (2016) revealed that high-frequency SCS yielded substantially better long-term outcomes than traditional SCS; while the precise mechanism of action remains unclear, it is believed that high-frequency SCS modulates the spinal cord to promote pain relief; dorsal root ganglion (DRG) stimulation — the ACCURATE trial (Deer et al [2017]) demonstrated superiority of DRG stimulation vs traditional SCS, especially for focal pain (eg, complex regional pain syndrome [CRPS], causalgia); DRG is occasionally used off-label for cervical spine pain; the SUNBURST trial (Deer et al [2018]) demonstrated superiority of the BURST waveform compared with tonic (traditional) SCS; differential targeted multiplexed (DTM) SCS — Fishman et al (2021) demonstrated an ≈80% responder rate for LBP,vs ≈51% with traditional SCS; Vallejo et al (2020) suggested sustained efficacy of DTM stimulation ≤12 mo on glial cell modulation in a rat model; closed-loop stimulation — regulates spinal energy via electrode feedback; the EVOKE trial (Mekhail et al [2020]) focused on evoked compound action potentials (eCAPs) to customize therapy for individual patients; each patient underwent implantation, and their specific eCAP was measured and programmed into the device to maintain stimulation within the therapeutic window; after a long-awaited introduction, closed-loop stimulation therapy recently entered the market in a limited rollout fashion

Indications for SCS: traditional indications include failed back surgery syndrome and CRPS types I and II; recently added indications include intractable LBP and LE pain, plus chronic pain in the trunk or limbs, though following a history of an injury or failed surgery

Efficacy of SCS: Peterson et al (2021) demonstrated more significant pain relief and improved symptoms for patients with painful diabetic neuropathy following treatment with high-frequency SCS vs conventional medical management; FDA approval for painful diabetic neuropathy followed; 24-mo data demonstrated improved sensory function in ≈65% of patients; high-frequency SCS also improved body mass index, QOL, sleep, and functionality, with no increased risk for infection despite increase in hemoglobin A_1C; in 2022, the FDA expanded high-frequency SCS to patients with intractable back pain when the patient is no longer a candidate for back surgery or when back surgery has not been previously performed, following demonstration of ≈70% pain reduction, ≈15% decrease in Oswestry disability index (ODI) score, and ≈50% decrease in opioid use following high-frequency SCS (Al-Kaisy et al [2020])

MRI compatibility: interventional pain therapies are increasingly being used in younger patients and patients with all kinds of comorbidities; ensuring MRI compatibility allows patients access to advanced imaging modalities, minimizing reliance on CT and reducing overall radiation exposure

Artificial intelligence (AI)-based platforms: AI-based platforms use data about effective waveforms, settings, and programming to help guide patients without the need to wait for an office visit or to coordinate with the device representative; newer SCS devices are equipped with cloud-based connectivity, enabling continuous monitoring of patient use and therapy efficacy, as well as prompt identification and resolution of issues (eg, low battery levels, suboptimal therapy adherence)

Intrathecal therapy: recent research focuses on use optimization; traditional high-dose monotherapy led to granuloma formation at the tip of the catheter and induced opioid hyperalgesia; Hamza et al (2012) and Grider et al (2016) demonstrated improved functional outcomes with microdosing of opioids and without oral supplementation; some providers use off-label admixture therapies with good results

Lumbar spinal stenosis

Intervertebral disk (IVD): drying and shrinkage of the intervertebral disks (IVDs) lead to changes in spinal curvature that transfer weight more posteriorly and cause central, lateral, and foraminal narrowing of recesses, resulting in neurogenic claudication; newer products attempt to supplement and rehydrate the IVD to restore its cushioning function; currently only one commercialized product exists, which provides cadaveric nucleus pulposus material via needle insertion (similar to diskography); the product available on the market differs from the one initially studied because of FDA-related changes

Posterior column: as disk degeneration progresses, the multifidus muscle attempts to carry the load as body weight posteriorly shifts, and it protectively contracts in response to axial back pain; over time, atrophy occurs, impairing stabilization; 3 yr following application of PNS to the multifidus muscle, Gilligan et al (2023) demonstrated ≥50% reduction in LBP for 77% of patients, complete resolution for 67%, and decrease in ODI scoring; insurance coverage is currently limited

Vertebral body: basivertebral nerve — the basivertebral nerve innervates the vertebral body and is implicated in pain generation; IVDs leak inflammatory mediators as they dry out, leading to reactive Modic changes in the bone; Koreckij et al (2021) demonstrated reduction of axial LBP and improvement in ODI scoring 24 mo following application of RFA to the basivertebral nerve; 31% of patients were pain-free at 24 mo; compression fractures — vertebroplasty and kyphoplasty are used to treat compression fractures; returning the vertebral body to near its original height and leveling out the weight distribution on the end plate helps prevent subsequent fractures and adjacent level fractures

Neurogenic claudication: patients experience LBP and LE pain and heaviness when forced to stand or walk upright, or may awake at night with LE pain or heaviness (if sleeping on the back), but experience profound relief with flexion; it is important to differentiate neurogenic claudication from vascular claudication; minimally invasive lumbar decompression — involves removing part of the ligamentum flavum to relieve pressure on the spinal cord to alleviate symptoms of neurogenic claudication; Staats et al (2018) demonstrated a safety profile comparable with epidurals; insurance coverage may be limited; interspinous spacers — wedged between spinous processes to block extension; a risk of subsidence over time exists because of the lack of fixation to the spine; interspinous spacers offer a solution for patients unable to undergo other decompression methods; minimally invasive lumbar stabilization — involves using various devices to provide stabilization and indirect decompression; Skoblar et al (2023) demonstrated a fusion rate of ≈93% over 1 yr following use of a lateral approach to a posterior fusion; Shah et al (2024) demonstrated a ≈50% reduction in pain scores 3 to 4 mo following implantation; in a study by Falowski et al (2023), 82% of patients reported improvement 3 mo after the procedure, and 65% of patients experienced clinically meaningful improvements in pain and function; only one adverse event occurred, which was unrelated to the device and did not produce long-term complications

Sacroiliac (SI) joint dysfunction: patients who are postpartum or have had lumbar spine surgery are especially susceptible; fusion of lumbar vertebrae can increase motion in the SI joints, leading to pain; symptoms include localized pain that can radiate to the, eg, buttock, thigh, groin, lateral calf; patients may have difficulty arising from chairs or car seats, or they may preferentially use one leg when ascending stairs; SI joint injections — are effective, but patients may become refractory to steroids; radiofrequency ablation — no longer covered by insurance; surgery — open surgical approaches, historically performed with a lateral approach, have mixed outcomes and significant risks; minimally invasive options show promise; interim data from Calodney et al (2022) demonstrated significant pain reduction, improved functionality, and fewer adverse events following posterior bone allograft, compared with use of the standard lateral bone allograft; 12-mo data revealed reduced anesthesia time, blood loss, and fluoroscopy exposure with a posterior vs lateral approach

Readings

Al-Kaisy A, Van Buyten JP, Amirdelfan K, et al. Opioid-sparing effects of 10 kHz spinal cord stimulation: a review of clinical evidence. Ann N Y Acad Sci. 2020;1462(1):53-64. doi:10.1111/nyas.14236; Calodney AK, Azeem N, Buchanan P, et al. Six month interim outcomes from SECURE: a single arm, multicenter, prospective, clinical study on a novel minimally invasive posterior sacroiliac fusion device. Expert Rev Med Devices. 2022;19(5):451-461. doi:10.1080/17434440.2022.2090244; Deer TR, Levy RM, Kramer J, et al. Dorsal root ganglion stimulation yielded higher treatment success rate for complex regional pain syndrome and causalgia at 3 and 12 months: a randomized comparative trial. Pain. 2017;158(4):669-681. doi:10.1097/j.pain.0000000000000814; Deer T, Slavin KV, Amirdelfan K, et al. Success using neuromodulation with BURST (SUNBURST) study: results from a prospective, randomized controlled trial using a novel burst waveform. Neuromodulation. 2018;21(1):56-66. doi:10.1111/ner.12698; Falowski SM, Raso LJ, Mangal V, et al. A prospective, observational, open-label, non-randomized, multicenter study measuring functional outcomes in a novel interspinous fusion device in subjects with low back pain: REFINE study. Pain Ther. 2023;12(1):187-199. doi:10.1007/s40122-022-00447-0; Fishman M, Cordner H, Justiz R, et al. Twelve-month results from multicenter, open-label, randomized controlled clinical trial comparing differential target multiplexed spinal cord stimulation and traditional spinal cord stimulation in subjects with chronic intractable back pain and leg pain. Pain Pract. 2021;21(8):912-923. doi:10.1111/papr.13066; Gartenberg A, Nessim A, Cho W. Sacroiliac joint dysfunction: pathophysiology, diagnosis, and treatment. Eur Spine J. 2021;30(10):2936-2943. doi:10.1007/s00586-021-06927-9; Grider JS, Etscheidt MA, Harned ME, et al. Trialing and maintenance dosing using a low-dose intrathecal opioid method for chronic nonmalignant pain: a prospective 36-month study. Neuromodulation. 2016;19(2):206-219. doi:10.1111/ner.12352; Kapural L, Yu C, Doust MW, et al. Comparison of 10-kHz high-frequency and traditional low-frequency spinal cord stimulation for the treatment of chronic back and leg pain: 24-month results from a multicenter, randomized, controlled pivotal trial. Neurosurgery. 2016;79(5):667-677. doi:10.1227/NEU.0000000000001418; Koreckij T, Kreiner S, Khalil JG, et al. Prospective, randomized, multicenter study of intraosseous basivertebral nerve ablation for the treatment of chronic low back pain: 24-month treatment arm results. N Am Spine Soc J. 2021;8:100089. doi:10.1016/j.xnsj.2021.100089; Petersen EA, Stauss TG, Scowcroft JA, et al. Effect of HIGH-FREQUENCY (10-kHz) spinal cord stimulation in patients with painful diabetic neuropathy: a randomized clinical trial. JAMA Neurol. 2021;78(6):687-698. doi:10.1001/jamaneurol.2021.0538; Shah A, Hagedorn JM, Latif U, et al. Posterior lateral arthrodesis as a treatment option for lumbar spinal stenosis: safety and early clinical outcomes. J Pain Res. 2024;17:107-116. doi:10.2147/JPR.S422736; Staats PS, Chafin TB, Golovac S, et al. Long-term safety and efficacy of minimally invasive lumbar decompression procedure for the treatment of lumbar spinal stenosis with neurogenic claudication: 2-year results of MiDAS ENCORE. Reg Anesth Pain Med. 2018;43(7):789-794. doi:10.1097/AAP.0000000000000868; Stearns LM, Abd-Elsayed A, Perruchoud C, et al. Intrathecal drug delivery systems for cancer pain: an analysis of a prospective, multicenter product surveillance registry. Anesth Analg. 2020;130(2):289-297. doi:10.1213/ANE.0000000000004425; Wilkes DM, Orillosa SJ, Hustak EC, et al. Efficacy, safety, and feasibility of the morphine microdose method in community-based clinics. Pain Med. 2018;19(9):1782-1789. doi:10.1093/pm/pnx132.

Disclosures

For this program, the following relevant financial relationships were disclosed and mitigated to ensure that no commercial bias has been inserted into this content: Dr. Bailey-Classen was a member of the advisory board for Biotronik and Spinal Simplicity, and served on the speaker’s bureau for Aurora Spine & Pain, Medtronic, Nevro, and Spinal Simplicity. Members of the planning committee reported nothing relevant to disclose. Dr. Bailey-Classen’s lecture includes information related to the off-label or investigational use of a therapy, product, or device.

Acknowledgements

Dr. Bailey-Classen was recorded at the 2023 Annual Convention and Conclave of the American Osteopathic College of Anesthesiologists, held September 30 to October 3, 2023, in Saint Petersburg, FL, and presented by the American Osteopathic College of Anesthesiologists. For information about upcoming CME activities from this presenter, please visit https://www.aocaonline.org. Audio Digest thanks the speakers and presenters for their cooperation in the production of this program.

CME/CE INFO

Accreditation:

The Audio- Digest Foundation is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians.

The Audio- Digest Foundation designates this enduring material for a maximum of 1.25 AMA PRA Category 1 Credits™. Physicians should claim only the credit commensurate with the extent of their participation in the activity.

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Lecture ID:

AN661502

Expiration:

This CME course qualifies for AMA PRA Category 1 Credits™ for 3 years from the date of publication.

Instructions:

To earn CME/CE credit for this course, you must complete all the following components in the order recommended: (1) Review introductory course content, including Educational Objectives and Faculty/Planner Disclosures; (2) Listen to the audio program and review accompanying learning materials; (3) Complete posttest (only after completing Step 2) and earn a passing score of at least 80%. Taking the course Pretest and completing the Evaluation Survey are strongly recommended (but not mandatory) components of completing this CME/CE course.

Estimated time to complete this CME/CE course:

Approximately 2x the length of the recorded lecture to account for time spent studying accompanying learning materials and completing tests.