Stellate ganglion block increases blood flow into the optic nerve head and the peripapillary retina in human

A Cross Talk between the Endocannabinoid System and Different Systems Involved in the Pathogenesis of Hypertensive Retinopathy

The prognosis of hypertension leads to organ damage by causing nephropathy, stroke, retinopathy, and cardiomegaly. Retinopathy and blood pressure have been extensively discussed in relation to catecholamines of the autonomic nervous system (ANS) and angiotensin II of the renin–angiotensin aldosterone system (RAAS) but very little research has been conducted on the role of the ECS in the regulation of retinopathy and blood pressure. The endocannabinoid system (ECS) is a unique system in the body that can be considered as a master regulator of body functions. It encompasses the endogenous production of its cannabinoids, its degrading enzymes, and functional receptors which innervate and perform various functions in different organs of the body. Hypertensive retinopathy pathologies arise normally due to oxidative stress, ischemia, endothelium dysfunction, inflammation, and an activated renin–angiotensin system (RAS) and catecholamine which are vasoconstrictors in their biological nature. The question arises of which system or agent counterbalances the vasoconstrictors effect of noradrenaline and angiotensin II (Ang II) in normal individuals? In this review article, we discuss the role of the ECS and its contribution to the pathogenesis of hypertensive retinopathy. This review article will also examine the involvement of the RAS and the ANS in the pathogenesis of hypertensive retinopathy and the crosstalk between these three systems in hypertensive retinopathy. This review will also explain that the ECS, which is a vasodilator in its action, either independently counteracts the effect produced with the vasoconstriction of the ANS and Ang II or blocks some of the common pathways shared by the ECS, ANS, and Ang II in the regulation of eye functions and blood pressure. This article concludes that persistent control of blood pressure and normal functions of the eye are maintained either by decreasing systemic catecholamine, ang II, or by upregulation of the ECS which results in the regression of retinopathy induced by hypertension.

Successful Treatment of Herpes Zoster Ophthalmicus Complicated by Intense Orbital Inflammation Using Laser Irradiation over the Stellate Ganglion

A 56-year-old man presented with right-sided headache and ptosis accompanied by a facial skin rash. He was diagnosed with herpes zoster ophthalmicus (HZO). Despite acyclovir and steroid therapy, the ocular symptoms worsened. Magnetic resonance imaging (MRI) revealed severe orbital inflammation and abnormal lesions in the right trigeminal nucleus and tract. The effects of re-administration of intravenous acyclovir and steroid pulse therapy were limited. Laser irradiation of the stellate ganglion (SGL) and high-dose oral prednisolone therapy were effective. Our experience suggests the efficacy of early multimodal treatment, including SGL, in treating ocular symptoms associated with HZO.

Bilateral stellate ganglion block for migraine: A case report

RATIONALE

Migraine is a recurrent, disabling neurovascular headache disorder. The patient's quality of life can be severely impaired by migraine attacks. Stellate ganglion block (SGB) can be used to relieve pain in the head, neck, and upper extremities. In the present cases, we performed SGB in 2 patients with migraine that responds poorly to drugs.

PATIENT CONCERNS

Patients 1 and 2 suffered from chronic, bilateral pulsating headache, accompanied by nausea and vomiting. Patient 1 presented with headache of 8 on the visual analog scale (VAS), and 37 on the migraine disability assessment (MIDAS). Patient 2 reported headache of 7 on the VAS, and 32 on the MIDAS.

DIAGNOSIS

The patients were diagnosed with migraine without aura based on the International Classification of Headache Disorders version 3.

INTERVENTIONS

Patient 1 was treated with bilateral SGB every week for a month and then every month for 3 months. Patient 2 received bilateral SGB every 2 weeks for a month and then every month for 3 months.

OUTCOMES

Four months after SGB, patient 1 reported pain intensity of 4 on VAS and 6 on MIDAS and patient 2 rated pain intensity of 3 on VAS, and 6 on MIDAS, respectively.

LESSONS

The SGB can be an effective option to improve headache-related disability and relieve pain intensity in the patients with refractory migraine.

Simultaneous influence of sympathetic autonomic stress on Schlemm's canal, intraocular pressure and ocular circulation

This study aimed to investigate changes in Schlemm's canal, intraocular pressure and ocular blood circulation following the activation of the sympathetic nervous system. Twenty healthy volunteers were enrolled in this study. The cold pressor test (CPT) was adopted. Cross-sectional area of Schlemm's canal (SCAR), superficial and deep retinal vessel densities (s-RVD;d-RVD), pupil diameter (PD), intraocular pressure (IOP), mean ocular perfusion pressure (MOPP) and heart rate variability (HRV) were measured at three time-points: baseline (T0) and 5 min (T1) and 10 min (T2) after the CPT. After cold stimulation, LF/HF index (the ratio of low frenquency and high frenquency) increased significantly. IOP decreased from 16.9 ± 1.9 mmHg at baseline to 16.4 ± 2.7 mmHg at T1 and to 15.2 ± 2.7 mmHg at T2. The nasal cross-sectional area of SCAR (SCAR-n) increased from 6283.9 ± 2696.2 µm2 at baseline to 8392.9 ± 3258.7 µm2 at T1 and to 10422.0 ± 3643.8 µm2 at T2. The temporal cross-sectional area of SCAR (SCAR-t) increased from 6414.5 ± 2218.7 µm2 at baseline to 8610.8 ± 2317.1 µm2 at T1 and to 11544.0 ± 4129.2 µm2 at T2. The expansion of Schlemm's canal was observed after the CPT might be caused by sympathetic nerve stimulation, subsequently leading to decreased IOP.

Predestinating Role of Cardiac Ganglia on Heart Life Expectancy in Rabbits After Brain Death Following Subarachnoid Hemorrhage: An Experimental Study

BACKGROUND

Cardiac ganglia are rechargeable batteries of the heart. The essential role of cardiac ganglia on cardiac life expectancy has not been examined following brain death. The aim of this study was to determine cardiac ganglia numbers and neuron density following subarachnoid hemorrhage (SAH).

METHODS

Twenty-five hybrid rabbits were grouped as control (n = 5), sham (n = 5), and SAH (n = 15). The SAH groups' animals were subjected to injections of lethal dose of 2.00 cc autologous blood into their cisterna magna until linear EEG was obtained. The hearts of all animals were extracted following intracardiac formalin injection and examined. Cardiac ganglia and normal/degenerated neuron densities of cardiac neurons were recorded.

RESULTS

The mean volume of normal neuron density of ganglia was 6.980 ± 830/mm³, and the degenerated neuron density of ganglia was 3 ± 1/mm³ in the control group, 6134 ± 712/mm³; 23 ± 9/mm³ in the sham group, 3456 ± 589; 1161 ± 72/mm³ in the surviving group; and 1734 ± 341/mm³, 4259 ± 865/mm³ in the dead animals in the SAH group. The algebraic results of heart work capacity (Wh) were estimated as 1375 ± 210 Wh in the control group, 1036 ± 225 in the sham group, 800 ± 110 Wh in the surviving group, and < 100 ± 20 in the dead animals in the SAH group. Degenerated cardiac neuron density/Wh correlation is statistically meaningful between the dead in the SAH group versus the SAH-surviving, sham, and control groups (P < .0005).

CONCLUSIONS

Normal cardiac ganglia numbers and/or cardiac ganglia neuron density may be related to cardiac survival following brain death after subarachnoid hemorrhage.

Effect of interscalene block on intraocular pressure and ocular perfusion pressure

BACKGROUND

Interscalene block (ISB) is commonly associated with Horner's syndrome due to spread of local anesthetic to the cervical sympathetic chain. Postganglionic neurons that originate from superior cervical ganglia form the sympathetic innervation of eye. Decrease in sympathetic tone may change intraocular pressure (IOP) and ocular perfusion pressure (OPP). The aim of the study was to investigate whether ISB affects IOP and/or OPP.

METHODS

Thirty patients scheduled for ambulatory shoulder surgery under regional anesthesia with a single-shot ISB (15 mL 0.5% bupivacaine and 15 mL 2% lidocaine) were recruited. The IOP and OPP in both eyes, mean arterial pressure (MAP), heart rate (HR) and end-tidal CO₂ (ETCO₂) were measured before ISB and 5, 10, 20, 30 and 60 min after ISB in the beach-chair position.

RESULTS

The baseline IOP and OPP were similar in the blocked and unblocked sides (IOP 17.60 ± 1.69 and 17.40 ± 1.96 respectively p = 0.432; OPP 49.80 ± 8.20 and 50 ± 8.07 respectively p = 0.432). The IOP in the blocked side significantly decreased between 10th to 60th min following ISB, compared to the baseline values (p < 0.001). The OPP in the blocked side significantly increased from 10th to 60th min (p < 0.001) whereas, there were no significant changes in IOP and OPP throughout the measurement period in the unblocked side.

CONCLUSIONS

ISB decreased IOP in the blocked side. ISB could be considered as a safe regional technique of choice in elderly patients at high risk for developing glaucoma.

Long-term Results of Stellate Ganglion Block in Patients with Olfactory Dysfunction

Background

Olfactory dysfunction, including anosmia and hyposmia is difficult to treat. Although the mechanism is not well known, stellate ganglion block (SGB) is used to treat olfactory dysfunction. There are no prior studies on the long-term effects of SGB on olfactory dysfunction. The purpose of this study was to evaluate the continuity of therapeutic effects and patient satisfaction with SGB treatment.

Methods

This was a follow-up study carried out via a telephonic survey. The olfactory function of the patient was evaluated using a visual analog scale (VAS). We checked VAS three times: VAS-I (pre-treatment VAS), VAS-A (post-treatment VAS), and VAS-C (VAS at follow up telephone survey). We divided the subjects into 2 groups according to their responsiveness to SGB: the responsive (R group) and the unresponsive groups (UR group). Patient satisfaction was evaluated using a Likert scale.

Results

Out of the 40 subjects, 37 responded to the telephone survey. In the UR group, there was difference in the olfactory function. However, in the R group, there were significant VAS differences; VAS-I was 9.6 ± 0.7, VAS-A was 5.1 ± 4.2, and VAS-C was 2.7 ± 2.7 (P < 0.05). On the Likert scale, patient satisfaction was as follows: grade 1, 17 patients (45.9%); grade 2, 6 patients (16.2%); grade 3, 6 patients (16.2%); and grade 4, 8 patients (21.6%).

Conclusions

SGB is a safe, long-lasting, and effective therapeutic modality for olfactory dysfunction treatment.

Human orbital sympathetic nerve pathways

PURPOSE

To determine pathways of sympathetic nerves from the orbital apex to the eyelids in human cadaver tissue using immunohistochemistry.

METHODS

Human cadaver orbit tissue was sectioned and immunolabeled with a monoclonal antityrosine hydroxylase antibody.

RESULTS

In the orbital apex, the nasociliary, frontal, lacrimal, and maxillary branches of the trigeminal nerve demonstrated intense staining upon entering the orbit. Immunoreactive axons from the nasociliary and frontal nerves were observed to join the extraocular motor nerves in the posterior orbit. A plexus of immunolabeled nerves was observed to accompany the ophthalmic artery as it entered the orbital apex. The ophthalmic artery and its branches throughout the orbit demonstrated staining of nerve fibers in the peripheral muscularis. The nasociliary nerve contributed sympathetic branches to the ciliary ganglion. Nerves passing through the ciliary ganglion and a few ganglion cell bodies demonstrated mild to moderate tyrosine hydroxylase reactivity. Axons within the short and long ciliary nerves demonstrated strong tyrosine hydroxylase reactivity and were observed to enter the posterior sclera and the suprachoroidal space. The lacrimal gland demonstrated mild pericapillary staining and occasional stromal nerve fibers reactive to the antityrosine hydroxylase antibody. Müller muscle and the inferior tarsal muscle possessed a strong tyrosine hydroxylase-reactive nerve supply that appeared to originate from the anterior terminal branches of the nasociliary and lacrimal nerves.

CONCLUSIONS

Sympathetic nerves enter the orbit via the first and second divisions of the trigeminal nerve and a plexus of nerves surrounding the ophthalmic artery. Extraocular motor nerves receive a sympathetic nerve supply from the sensory nerves in the posterior orbit. Some ciliary ganglion cell bodies demonstrated tyrosine hydroxylase-like reactivity, suggesting a sympathetic modulatory role for the ciliary ganglion. Sympathetics innervate ocular structures via the posterior ciliary nerves. Sympathetic axons travel anteriorly in the orbit via the nasociliary and lacrimal nerves to innervate the sympathetic eyelid muscles. Sympathetic nerves also travel with the frontal branch of the ophthalmic nerve to innervate the forehead skin. The ophthalmic artery and all of its branches contain a perivascular sympathetic nerve supply that may be involved in regulation of blood flow to ocular and orbital structures.