4 Minimally Invasive Procedures for Pain Treatment

At least 10% of the world’s population (and by some estimates up to 40% of the population in some countries) suffer from chronic pain(1). These and other conditions characterized by pain pose an emotional, physical, and financial burden for sufferers and their families. Most people with chronic pain report feeling less healthy overall, are more vulnerable to depression, and find that the pain interferes with daily activities and with relationships and social interactions. Predictably, increased pain severity is also associated with reduced functioning and well-being.

According to the WHO’s Global Burden of Disease study(2), conditions characterized or defined by the presence of pain (low back pain, neck pain, other musculoskeletal disorders, migraine, etc.) account for 5 of the top 10 conditions responsible for the most Years Lived with Disability globally, a measure of loss of productivity and quality of life.

Unfortunately, many of the most common pain generators are located in areas which aren’t reachable with surgery, or which pose a risk of high complications. Luckily, improved imaging capabilities and new interventions available in the IR space are enabling radiologists to play an ever larger role in pain management, without surgery or high risk, and all thanks to the array of minimally invasive procedures at their fingertips.

Indeed, less invasive, percutaneous approaches have largely supplanted open procedures(3). Interventional radiologists are able to use imaging guidance to access areas unreachable by surgery, and treat them safely and effectively using ablative technologies. More recent innovations in the form of targeted radiotherapy and focused ultrasound often eliminate the need for conventional surgery or punctures altogether.

Interventional radiologists are in a unique position to support patients with chronic pain, without surgery and without the use of dangerous or addictive pain medication. Let’s take a look at some of the most promising minimally invasive and non-invasive procedures for pain treatment available today.

1. Spinal ESI (Epidural Steroid Injections)

Back pain causes a significant fraction of the overall burden of chronic pain. In this procedure, a steroid or corticosteroid fluid is injected into the epidural space, or the area surrounding the spinal nerves, which reduces inflammation. This is commonly used after physical therapy and other conventional treatments have failed(4).

Spinal ESI can treat:

• Vertebral bone spurs (osteophytes)

• a herniated or bulging disk that pinches nerves, causing pain

• degeneration of the spine, or spondylolysis degeneration

• Failed back surgery syndrome (a term describing people who have had one or more spinal surgeries for pain, yet still experience pain)

• Narrowing of the spaces within the spine, also known as spinal stenosis

• nerve root irritation caused by scoliosis

• Other injuries to spinal nerves, vertebrae and surrounding tissues

For complex access routes, clinical studies have shown that navigation support is a promising tool to safely reach the target. However, only around 50% of patients experience relief, and even then, the effects can be temporary, lasting from a few weeks to 3 months.

2. Percutaneous Cryoneurolysis for Nerve Blocks

Nerve blocks (injecting an anesthetic or steroid near the nerve which is transmitting the pain) are commonly used ahead of medical procedures as an alternative for general anesthesia, but can also be effectively utilized for longer-lasting relief from pain(5). Typically guided via ultrasound, fluoroscopy or CT, the injection reduces inflammation or blocks the pain signals coming through the nerve. However, the effect is temporary as the medication wears off.

Percutaneous cryoneurolysis is a newer method for long-lasting nerve blocks. Utilizing a similar mechanism as pharmaceutical nerve blocks, percutaneous cryoneurolysis is performed by placing a probe near the nerve where extremely cold temperatures are used to freeze and destroy a small section of the nerve. This blocks pain signals from transmitting.

Because nerves control not only sensation but also movement, some treatments have a risk of loss of motor function. Given the nerve’s ability to regenerate, however, it is in some cases possible to induce a degeneration which is followed by a regeneration – meaning loss of motor skills can be recovered. This is known as percutaneous neuroregenerative therapy.

Cryoneurolysis is a feasible treatment for a variety of nerves and anatomical locations and a procedure which has the potential for long-term reduction of pain without the use of medication.

3. RFA Nerve Ablation

Utilizing a similar mechanism as cryoneurolysis, Radiofrequency Ablation (RFA) neurolysis uses radio waves to create heat and damage tissue. Most frequently, RFA is used as a cancer treatment given its precise ability to target and destroy tumour cells. However, RFA is increasingly used to treat pain by damaging pain-sensing nerves.

In RFA, a probe is placed into the target tissue where it emits an electrical current to transmit radio waves to the surrounding tissue, which heats up to temperatures more than 45°C –50°C (sustained for more than 20 seconds), after which permanent cellular destruction occurs causing cells to die(3).

A benefit of RFA is that the operator can quickly stimulate the nerve using the electrode before applying heat, enabling a confirmation of correct placement of the probe before any cellular destruction occurs. However, due to the absence of real-time imaging modalities, it is not possible to visualize the extent of the ablation as it is taking place. Initial clinical research shows that navigation systems for RF ablation are promising for precise and sustained location of the target(6).

Interventional radiologists can use imaging guidance to access areas unreachable by surgery, and treat them safely and effectively using ablative technologies. More recent innovations in the form of targeted radiotherapy and focused ultrasound often eliminate the need for conventional surgery or punctures altogether. with relationships and social interactions. Predictably, increased pain severity is also associated with reduced functioning and well-being.

4. High frequency focused ultrasound /High Intensity Focused Ultrasound (HIFU)

High-intensity focused ultrasound is a non-invasive technique which is effective for treating bone metastases, uterine fibroids, and essential tremors(7). Using ultrasound or MRI guidance, high-intensity ultrasound waves are focused on a small, clearly-defined location, resulting in increased temperatures and a precise, localized ablation of the area.

Focused ultrasound can reduce pain through a variety of mechanisms, including tissue denervation, tumor mass reduction, and neuromodulation, that can influence different pathways at the origin of the pain. In cancer patients, this treatment may represent what is known as a multimodality approach to treatment—combining pain relief, improved local drug delivery and radiation therapy effects, and stimulation of anticancer-specific immune responses.

In summary

Options for chronic pain treatment are more expansive and safer than ever, in large part thanks to innovations in the radiology department. Interventional radiologists have the opportunity to become integral parts of palliative and treatment-oriented care teams, and are more than ever central to the wellbeing of patients.

References

1. Henschke N, Kamper SJ, Maher CG. The epidemiology and economic consequences of pain. Mayo Clin Proc. 2015;90(1):139-147. doi:10.1016/j.mayocp.2014.09.010

2. Kassebaum NJ, Arora M, Barber RM, et al. Global, regional, and national disability-adjusted life-years (DALYs) for 315 diseases and injuries and healthy life expectancy (HALE), 1990–2015: a systematic analysis for the Global Burden of Disease Study 2015. The Lancet. 2016;388(10053):1603-1658. doi:10.1016/S0140-6736(16)31460-X

3. Tan H, Stedelin B, Bakr SM, Nerison C, Raslan AM. Neurosurgical Ablation for Pain: A Technology Review. World Neurosurg. 2023;170:114-122. doi:10.1016/J.WNEU.2022.11.047

4. Epidural Steroid Injection (ESI): What It Is, Benefits, Risks & Results. Accessed March 13, 2023. https://my.clevelandclinic.org/health/treatments/22301-epidural-steroid-injection-esi

5. Bittman RW, Behbahani K, Gonzalez F, Prologo JD. Ablative Therapy: Part 2: Interventional Cryoneurolysis: What Is the Same, What Is Different, What Is New? Semin Intervent Radiol. 2019;36(5):374. doi:10.1055/S-0039-1696705

6. Grigoriadis S, Filippiadis D, Stamatopoulou V, Alexopoulou E, Kelekis N, Kelekis A. Navigation Guidance for Percutaneous Splanchnic Nerve Radiofrequency Neurolysis: Preliminary Results. Medicina (B Aires). 2022;58(10). doi:10.3390/MEDICINA58101359

7. Dababou S, Marrocchio C, Scipione R, et al. High-intensity focused ultrasound for pain management in patients with cancer. Radiographics. 2018;38(2):603-623. doi:10.1148/RG.2018170129