The Bilateral Effect of Stellate Ganglion Block on the Facial Skin Blood Flow:

Changes in blood flow at the mandibular angle and Horner syndrome in a rat model of superior cervical ganglion block

Background

A stellate ganglion block (SGB) causes increased blood flow in the maxillofacial region, exhibiting the potential for regenerative effects in damaged tissue. The focus of this study was to understand the efficacy of SGB for regenerative effects against nerve damage. A rat model of the superior cervical ganglion block (SCGB) was created instead of SGB, and facial blood flow, as well as sympathetic nervous system function, were measured.

Methods

A vertical incision was made on the left side of the neck of a Wistar rat, and a 5-mm resection of the superior cervical ganglion was performed at the back of the bifurcation of the internal and external branches of the left common carotid artery. Blood flow in the skin at the mandibular angle and mean facial temperature were measured using a laser-Doppler blood flow meter and a thermographic camera, respectively, over a 5-week period after the block. In addition, the degree of ptosis and miosis were assessed over a period of 6 months.

Results

The SCGB rat showed significantly higher blood flow at the mandibular angle on the block side (P < 0.05) for 3 weeks, and significantly higher skin temperature (P < 0.05) for 1 week after the block. In the SCGB rat, ptosis and miosis occurred immediately after the block, and persisted even 6 months later.

Conclusions

SCGB in rats can cause an increase in the blood flow that persists over 3 weeks.

Can nerve regeneration on an artificial nerve conduit be enhanced by ethanol-induced cervical sympathetic ganglion block?

This study aimed to determine whether nerve regeneration by means of an artificial nerve conduit is promoted by ethanol-induced cervical sympathetic ganglion block (CSGB) in a canine model. This study involved two experiments—in part I, the authors examined the effect of CSGB by ethanol injection on long-term blood flow to the orofacial region; part II involved evaluation of the effect of CSGB by ethanol injection on inferior alveolar nerve (IAN) repair using polyglycolic acid-collagen tubes. In part I, seven Beagles were administered left CSGB by injection of 99.5% ethanol under direct visualization by means of thoracotomy, and changes in oral mucosal blood flow in the mental region and nasal skin temperature were evaluated. The increase in blood flow on the left side lasted for 7 weeks, while the increase in average skin temperature lasted 10 weeks on the left side and 3 weeks on the right. In part II, fourteen Beagles were each implanted with a polyglycolic acid-collagen tube across a 10-mm gap in the left IAN. A week after surgery, seven of these dogs were administered CSGB by injection of ethanol. Electrophysiological findings at 3 months after surgery revealed significantly higher sensory nerve conduction velocity and recovery index (ratio of left and right IAN peak amplitudes) after nerve regeneration in the reconstruction+CSGB group than in the reconstruction-only group. Myelinated axons in the reconstruction+CSGB group were greater in diameter than those in the reconstruction-only group. Administration of CSGB with ethanol resulted in improved nerve regeneration in some IAN defects. However, CSGB has several physiological effects, one of which could possibly be the long-term increase in adjacent blood flow.

Effects of Linearly Polarized Near-Infrared Irradiation Near the Stellate Ganglion Region on Pain and Heart Rate Variability in Patients with Neuropathic Pain

Background

Neuropathic pain associated with sympathetic overactivity can be effectively relieved by light irradiating the region near stellate ganglion (SGI), applied as an alternative to a conventional sympathetic blockade. The clinical effect of SGI on heart rate variability (HRV) and its association with pain outcomes require investigation.

Objective

This study attempted to identify the effects of SGI on pain outcomes and HRV indices and to determine the association between pain and HRV outcomes.

Design

A prospective double-blind, randomized study.

Setting

An outpatient pain medicine clinic.

Subjects and Methods

A total of 44 patients were enrolled and randomized into the experimental group ( n = 22) and control group ( n = 22). The experimental group received 12 sessions (twice weekly) of standard SGI, whereas the control group received the same protocol with sham irradiation. Pain and HRV were measured before and after each irradiation session. All outcome measures used in the first- and second-half treatment courses were analyzed.

Results

Pain and HRV outcome measures of the experimental group significantly improved after SGI when compared with the control group in both courses. Considering time and frequency domains, the changes in HRV in the second-half treatment course exceeded those in the first-half treatment course. Pain was significantly associated with postirradiated HRV indices ( P < 0.001).

Conclusions

Twelve sessions of SGI exerted time-dependent positive effects on pain and sympathovagal imbalance. HRV outcomes, including time and frequency domains, were an independent indicator of the clinical efficiency of SGI for treating pain in patients with neuropathic pain.

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.

Mesial temporal lobe seizures may activate thermoregulatory mechanisms in humans: an infrared study of facial temperature

Facial temperature T(f), an important link in cerebral thermoregulation and an ignored index of autonomic activity, was studied in three patients with mesial temporal epilepsy. Sets of infrared images were obtained automatically during seizures and also hourly, round-the-clock. For each patient, scan sets were sorted into: (1) ictal; (2) interictal with negligible motion; and (3) interictal with motion. Comparisons of mean, variance, and trend in each scan set among these groups showed considerable variability. However, significant trends in T(f) occurred (P<0.05) in two-thirds of seizures in one patient, three-fourths in another, and two-ninths in the third, consisting of steady decreases in T(f) beginning at peak seizure intensity R(max) and continuing into the postictus. Maximal ictal T(f) was greater than interictal T(f) (P<0.05), but it negatively correlated with R(max) in two subjects. The ictal changes in T(f), which may have a homeostatic role, suggest activation of thermoregulatory mechanisms during mesial temporal seizures.

MR guidance of sympathetic nerve blockade: measurement of vasomotor response initial experience in seven patients

The authors performed sympathetic nerve blockades in seven patients with peripheral ischemia and possible autonomic dysfunction. Magnetic resonance (MR) imaging was used to guide needle placement, to monitor distribution of injected agents, and to measure increases in blood flow, which were as much as 10-fold. MR imaging can provide both procedural imaging guidance and measurement of efficacy for sympathetic nerve blocks.