Cryoneurolysis for cervicogenic headache - a double blinded randomized controlled study

A Narrative Review of Ultrasound-Guided and Landmark-based Percutaneous Cryoneurolysis for the Management of Acute and Chronic Pain

PURPOSE OF REVIEW

Cryoneurolysis refers to the process of reversibly ablating peripheral nerves with extremely cold temperatures to provide analgesia for weeks to months. With ultrasound-guidance or landmark-based techniques, it is an effective modality for managing both acute and chronic pain. In this review, we summarize the reported literature behind its potential applications and efficacy.

RECENT FINDINGS

Here, we summarize several studies (from case reports to clinical trials) describing the use of ultrasound-guided and landmark-based cryoneurolysis for acute and chronic pain. Acute pain indications included pain related to knee arthroplasty, limb amputations, mastectomies, shoulder surgery, rib fractures, and burn. Chronic pain indications included chronic knee pain (due to osteoarthritis), shoulder pain, painful neuropathies, postmastectomy pain syndrome, phantom limb pain, facial pain/headaches, foot/ankle pain, inguinal pain, and sacroiliac joint pain. For both acute and chronic pain indications, more high quality randomized controlled clinical trials are needed to definitively assess the efficacy of cryoneurolysis versus other standard therapies for a multitude of pain conditions.

Applications of Cryoneurolysis in Chronic Pain Management: a Review of the Current Literature

PURPOSE OF REVIEW

The purpose of this review is to evaluate and summarize the literature investigating cryoneurolysis in the treatment of various chronic pain pathologies.

RECENT FINDINGS

There is an increasing amount of interest in the use of cryoneurolysis in chronic pain, and various studies have investigated its use in lumbar facet joint pain, SI joint pain, post-thoracotomy syndrome, temporomandibular joint pain, chronic knee pain, phantom limb pain, neuropathic pain, and abdominal pain. Numerous retrospective studies and a more limited number of prospective, sham-controlled prospective studies suggest the efficacy of cryoneurolysis in managing these chronic pain pathologies with a low complication rate. However, more blinded, controlled, prospective studies comparing cryoneurolysis to other techniques are needed to clarify its relative risks and advantages.

Ultrasound-controlled cryoneurolysis for peripheral mononeuropathies: a retrospective cohort study

Aim: Cryoneurolysis is a potential therapy for peripheral mononeuropathies, but randomized studies of its effects on the duration of pain reduction are lacking. Methods: This retrospective cohort study evaluated the analgesic effects of cryoneurolysis on patients with refractory peripheral mononeuropathy. We included 24 patients who underwent ultrasound-guided cryoneurolysis between June 2018 and July 2022. The daily maximum pain level was recorded using a numerical rating scale before and 1, 3 and 6 months after the procedure. Results: At 1 month, 54.2% of patients reported pain reduction of at least 30%. This percentage was significantly lower at 3 and 6 months (13.8 and 9.1%, respectively). Conclusion: Our results suggest that repeated cryoneurolysis may be a viable treatment for refractory mononeuropathy. Further investigations are needed.

Outcomes of Surgical Treatment of Migraines: A Systematic Review & Meta-Analysis

Background: Migraine surgery at 1 of 6 identified "trigger sites" of a target cranial sensory nerve has rapidly grown in popularity since 2000. This study summarizes the effect of migraine surgery on headache severity, headache frequency, and the migraine headache index score which is derived by multiplying migraine severity, frequency, and duration. Materials and Methods: This is a PRISMA-compliant systematic review of 5 databases searched from inception through May 2020 and is registered under the PROSPERO ID: CRD42020197085. Clinical trials treating headaches with surgery were included. Risk of bias was assessed in randomized controlled trials. Meta-analyses were performed on outcomes using a random effects model to determine the pooled mean change from baseline and when possible, to compare treatment to control. Results: 18 studies met criteria including 6 randomized controlled trials, 1 controlled clinical trial, and 11 uncontrolled clinical trials treated 1143 patients with pathologies including migraine, occipital migraine, frontal migraine, occipital nerve triggered headache, frontal headache, occipital neuralgia, and cervicogenic headache. Migraine surgery reduced headache frequency at 1 year postoperative by 13.0 days per month as compared to baseline (I2 = 0%), reduced headache severity at 8 weeks to 5 years postoperative by 4.16 points on a 0 to 10 scale as compared to baseline (I2 = 53%), and reduced migraine headache index at 1 to 5 years postoperative by 83.1 points as compared to baseline (I2 = 2%). These meta-analyses are limited by a small number of studies that could be analyzed, including studies with high risk of bias. Conclusion: Migraine surgery provided a clinically and statistically significant reduction in headache frequency, severity, and migraine headache index scores. Additional studies, including randomized controlled trials with low risk-of-bias should be performed to improve the precision of the outcome improvements.

Nerve blocks for occipital headaches: A systematic review and meta-analysis

Migraine surgeons have identified six "trigger sites" where cranial nerve compression may trigger a migraine. This study investigates the change in headache severity and frequency following nerve block of the occipital trigger site. This PRISMA-compliant systematic review of five databases searched from database inception through May 2020 is registered under the PROSPERO ID: CRD42020199369. Only randomized controlled trials utilizing injection treatments for headaches with pain or tenderness in the occipital scalp were included. Pain severity was scored from 0 to 10. Headache frequency was reported as days per week. Included were 12 RCTs treating 586 patients of mean ages ranging from 33.7 to 55.8 years. Meta-analyses of pain severity comparing nerve blocks to baseline showed statistically significant reductions of 2.88 points at 5 to 20 min, 3.74 points at 1 to 6 weeks, and 1.07 points at 12 to 24 weeks. Meta-analyses of pain severity of nerve blocks compared with treatment groups of neurolysis, pulsed radiofrequency, and botulinum toxin type A showed similar headache pain severity at 1 to 2 weeks, and inferior improvements compared with the treatment groups after 2 weeks. Meta-analyses of headache frequency showed statistically significant reductions at 1 to 6-week follow-ups as compared with baseline and at 1 to 6 weeks as compared with inactive control injections. The severity and frequency of occipital headaches are reduced following occipital nerve blocks. This improvement is used to predict the success of migraine surgery. Future research should investigate spinous process injections with longer follow-up.

Relative Effects of Various Factors on Ice Ball Formation and Ablation Zone Size During Ultrasound-Guided Percutaneous Cryoneurolysis: A Laboratory Investigation to Inform Clinical Practice and Future Research

INTRODUCTION

Ultrasound-guided percutaneous cryoneurolysis provides analgesia using cold temperatures to reversibly ablate peripheral nerves. Cryoneurolysis probes pass a gas through a small internal annulus, rapidly lowering the pressure and temperature, forming an ice ball to envelope the target nerve. Analgesia is compromised if a nerve is inadequately frozen, and laboratory studies suggest that pain may be paradoxically induced with a magnitude and duration in proportion with the incomplete ablation. We therefore investigated the relative effects of various factors that may contribute to the size of the ice ball and the effective cryoneurolysis zone.

METHODS

A cryoprobe was inserted into a piece of meat, a gas was passed through for 2 min, and the resulting ice ball width (cross-section) and length (axis parallel to the probe) were measured using ultrasound, with the temperature evaluated in nine concentric locations concurrently.

RESULTS

The factor with the greatest influence on ice ball size was probe gauge: in all probe types, a change from 18 to 14 increased ice ball width, length, and volume by up to 70%, 113%, and 512% respectively, with minimum internal temperature decreasing as much as from -5 to -32 °C. In contrast, alternating the type of meat (chicken, beef, pork) and the shape of the probe tip (straight, coudé) affected ice ball dimensions to a negligible degree. The ice ball dimensions and the zone of adequate temperature drop were not always correlated, and, even within a visualized ice ball, the temperature was often inadequate to induce Wallerian degeneration.

CONCLUSIONS

Percutaneous probe design can significantly influence the effective cryoneurolysis zone; visualizing a nerve fully encompassed in an ice ball does not guarantee adequate treatment to induce the desired Wallerian degeneration because ice forms at temperatures between 0 and -20 °C, whereas only temperatures below -20 °C induce Wallerian degeneration. The correlation between temperatures in isolated pieces of meat and perfused human tissue remains unknown, and further research to evaluate these findings in situ appears highly warranted.

Efficacy of interventional treatment strategies in the management of patients with cervicogenic headache- A systematic review

Cervicogenic headache (CeH) is caused by the disorder of the cervical spine and its anatomical structures. Patients who fail to respond to conservative therapies can undergo interventional treatment. The purpose of this review is to describe the various interventions and compare their relative efficacies. Although a few reviews have been published focusing on individual interventions, reviewing studies on other available treatments and establishing the most efficacious approach is still necessary. We performed a systematic review of studies available on the various interventions for CeH. The PubMed, Embase, and Cochrane databases were searched for literature published between January 2001 and March 2021. Based on the inclusion criteria, 23 articles were included. Two reviewers independently extracted the data from the studies and summarized them in a table. Eleven of twenty-three studies evaluated the effect of radiofrequency ablation (RFA), 5 evaluated occipital nerve blocks, 2 each for facet joint injections and deep cervical plexus blocks, and 1 study each evaluated atlantoaxial (AA) joint injections, cervical epidural injection, and cryoneurolysis. Most of the studies reported pain reduction except 2 studies on RFA. In conclusion, based on the available literature, occipital nerve blocks, cervical facet joint injection, AA joint injection, deep cervical plexus block, cervical epidural injection may be reasonable options in refractory cases of CeH. RFA was found to have favorable long-term outcomes, while better safety has been reported with pulsed therapy. However, our review revealed only limited evidence, and more randomized controlled trials are needed to provide more conclusive evidence.

Efficacy and Safety of Cryoneurolysis for Treatment of Chronic Head Pain Secondary to Occipital Neuralgia: A Pilot Study

Purpose

Treatment of chronic pain associated with occipital neuralgia (ON) is complex, and no consensus statement or guidelines have been published for ON management. This pilot study evaluated the efficacy and safety of cryoneurolysis for management of ON-associated chronic pain.

Patients and Methods

The study was a prospective, multicenter, nonrandomized cohort study assessing the degree and duration of clinical effect of cryoneurolysis therapy for reducing pain in patients diagnosed with unilateral or bilateral ON. The primary outcome measure was improvement in pain due to ON from baseline to day 7, measured on an 11-point numeric rating scale for pain. Secondary outcome measures included duration of treatment effects and safety events, including anticipated observations and adverse events. Treatment effect was assessed at days 7, 30, and 56 by asking the patient if they were continuing to experience a treatment effect, with potential responses of “effect,” “no effect,” or “no longer effective.” A posttreatment questionnaire evaluated patient satisfaction.

Results

Twenty-six patients (9 men, 17 women) with a mean age of 49.1 years enrolled and completed the study. A total of 64% (16/25) of participants reported a clinically important improvement of ≥2 points in numeric rating scale pain scores at day 7; similar results persisted to day 30. Treatment effects were reported by 50% (13/26) of participants at day 30, with a continued effect reported by 35% (9/26) of participants at day 56. Overall, ~70% of participants were satisfied with treatment at 7, 30, and 56 days. No serious anticipated observations, adverse events, or unanticipated adverse device effects were reported.

Conclusion

Cryoneurolysis provided significant relief from pain associated with ON ≤30 days after treatment and had an acceptable safety profile.