Efficacy and Safety of Percutaneous Ozone Injection Around Gasserian Ganglion for the Treatment of Trigeminal Neuralgia: A Multicenter Retrospective Study

CT-guided ozone-mediated lumbar-renal sympathetic denervation for resistant hypertension treatment: A pilot single-arm clinical trial

BACKGROUND

Renal sympathetic denervation (RDN) reduces blood pressure (BP).

METHODS

This single-arm open-label study enrolled patients with resistant hypertension (RH) and treat them by CT-guided ozone mediated lumbar-renal sympathetic denervation (L-RDN). The primary endpoint was to assess the changes of BP over 24-h ambulatory BP monitoring (ABPM) and to evaluate the anti-hypertensive medication burden (AHMB) at 3-month follow-up. This study was registered in Chictr.org.cn (ChiCTR2300071375).

RESULTS

17 patients (mean age 65.12 ± 10.77 years) with AHMB of 4.12 ± 1.11 were enrolled. After the procedure, 7 patients (46.7 %) matched the criteria for antihypertensive medication reduction. The AHMB decreased to 3.87 ± 0.96 for the whole objectives and from 3.87 ± 0.96 to 3.55 ± 0.78 for patients with normal baseline renal function. On top of the lessened AHMB, L-RDN further reduced morning systolic BP (SBP) by -8.6 ± 4.0 mmHg (p = 0.034) and diastolic BP (DBP) by -4.6 ± 2.1 mmHg (p = 0.032) for all participants and morning SBP by -13.2 ± 3.6 mmHg (p < 0.001), morning DBP by -6.2 ± 2.4 mmHg (p = 0.011) and daytime SBP by -4.1 ± 1.6 mmHg (p = 0.009) for those with normal baseline renal function at 3-month of follow-up. No adverse events were reported intra- and post operation.

CONCLUSIONS

CT-guided ozone-mediated L-RDN might be an innovative approach of RDN for treating RH. Confirmatory studies are warranted.

Chemogenetic inhibition of trigeminal ganglion neurons attenuates behavioural and neural pain responses in a model of trigeminal neuropathic pain

BACKGROUND

Nerve injury can lead to ectopic activation of injured nociceptorsand central sensitization characterized by allodynia and hyperalgesia. Reduction in the activity of primary afferent neurons has been shown to be sufficient in alleviating peripherally generated pain. The cell bodies of such trigeminal nociceptors are located in the trigeminal ganglia (TG) with central processes that terminate in the brainstem trigeminal nucleus caudalis (TNC). The TG is therefore a strategic locus where afferent input can be manipulated. We hypothesized that chemogenetic inhibition of TG would suppress TNC neuronal activity and attenuate pain behaviour in a rat model of painful traumatic trigeminal neuropathy (PTTN).

METHODS

Trigeminal neuropathic pain was induced in adult male Sprague-Dawley rats (n = 24) via chronic constriction injury to the infraorbital nerve (ION-CCI). Naïve and sham rats were used as controls (n = 20/group). Rats within each group received TG-directed microinjections of AAV virus containing either the inhibitory hM4Di-DREADD construct or EGFP.

RESULTS

In the ION-CCI group, systemic administration of the DREADD agonist clozapine N-oxide (CNO) reversed the hypersensitivity phenotype in animals expressing hM4Di but not EGFP. CNO-mediated activation of hM4Di DREADD in ION-CCI animals was also associated with reduced Fos expression in the TNC elicited by repeated mechanical stimulation of the dermatome ipsilateral to the injury. There was no effect of CNO on pain behaviour or TNC Fos expression in eGFP animals.

CONCLUSION

Our results indicate that DREADDs may offer an effective therapeutic approach for treatment of trigeminal neuropathic pain.

SIGNIFICANCE

Trigeminal neuropathic pain is highly resistant to therapy and we are in dire need of novel approaches. This study provides further evidence for the successful application of DREADDs as an effective tool for modulating central nervous system function. CNO mediated activation of hM4Di-DREADDs in the trigeminal ganglion (TG) attenuates nerve injury induced neuropathic pain by acting on hyperactive TG cells. It also establishes the TG as an effective target to manage pain in the face and head. Accessing the TG in clinical populations is a relatively simple and safe procedure, making this approach highly significant. Moreover, the methodology described here has applications in trigeminal neuropathic pain from traumatic other etiologies and in spinal neuropathic pain. Chronic pain syndromes are characterized by a progressive failure of brain centers to adequately inhibit pain and as these are identified, we may be able to target them for therapy. Therefore, our findings might have wide application in chronic pain syndromes.

Recent Advances in Trigeminal Neuralgia and Its Management: A Narrative Review

Trigeminal neuralgia (TN) is a chronic facial pain condition that affects one or more divisions of the trigeminal nerve (5th cranial nerve). It can be idiopathic, primary, or secondary. The cornerstone of the therapy has been antiepileptic medications, peripheral nerve blocks with various neurolytic agents, and surgical procedures. With the advent of newer technologies, minimally invasive neurolytic techniques like low-level laser therapy and ozone injection have revolutionized the management of TN. Novel drugs like vixotrigine and eslicarbazepine have been promising in reducing the frequency and severity of attacks. Inhaled carbon dioxide too has shown promising results in initial trials. Neuromodulation has given robust data in controlling neuralgic pain especially refractory to medical management. Pulsed radiofrequency has been used with increasing success and the side effects like dysesthesia and paresthesia are less. Cryotherapy, neural prolotherapy, and fiber knife techniques have helped us believe that TN can be controlled and cured. The need of the hour is to develop and explore newer modalities for trigeminal neuralgia treatment with minimum side effects. In this narrative review, we have tried to shed light into the newer modalities of treatment of TN along with new clinical classification for better disease recognition and management.