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Background and Objective Bleeding into the retropharyngeal space is a potential complication in stellate ganglion block (SGB). Retropharyngeal hematoma formation is considered to be due to damage of small arteries in the region, although only scanty details of the region are available. The aim of this study was to map the risk blood vessels in the retropharyngeal space to avoid accidental damage during SGB. Methods Contrast-enhanced 3-dimensional computed tomography images performed on 80 patients were reanalyzed retrospectively to construct detailed map of cervical blood vessels that are prone to damage and bleeding during SGB. Results Of the 160 bilateral necks, 6 (3.8%) and 82 (51.3%) small arteries were identified in the medial portions of the ventral surface of the transverse processes of the sixth and seventh cervical vertebrae, respectively. In particular, 5 of the 6 small arteries detected in the medial portion of the ventral surface of the transverse process of the sixth cervical vertebra were the inferior thyroid artery (ITA). Of the 160 vertebral arteries, 2 arteries were missing, 4 (2.5%) entered the transverse foramen of the fifth cervical vertebra, whereas 1 artery (0.6%) entered the transverse foramen of the fourth cervical vertebra. Conclusions Three-dimensional computed tomography identified the ITA in the medial portion of the ventral surface of the transverse process of the sixth cervical vertebra. The risk vessels of retropharyngeal hematoma during SGB could include the ITA.

BackgroundSympathetic blocks (SB) are commonly used to treat pain from complex regional pain syndrome (CRPS). However, there are currently no guidelines to assist pain physicians in determining the best practices when using and performing these procedures.MethodsA 32-question survey was developed on how SBs are used and performed to treat CRPS. The survey was conducted online via SurveyMonkey. The responses were statistically analyzed using descriptive statistics, and comparing academic versus non-academic, and fellowship versus non-fellowship-trained physicians.ResultsA total of 248 pain physicians responded with a response rate of 37%. Forty-four percent of respondents schedule the first SB at the first clinic visit; 73% perform one to three consecutive blocks; over 50% will repeat the block if a patient receives at least 50% pain relief from the previous one lasting 1–7 days.Fifty-four percent of respondents perform stellate ganglion blocks (SGB) at the C6 vertebral level, 41% at C7; 53% perform lumbar sympathetic blocks (LSB) at L3 level, 39% at L2; 50% use fluoroscopy to guide SGB, 47% use ultrasound. More respondents from academic than non-academic centers use ultrasound for SGB. About 75% of respondents use a total volume of 5–10 mL for SGB and 10–20 mL for LSB. The most commonly used local anesthetic is 0.25% bupivacaine. About 50% of respondents add other medications, mostly steroids, for these blocks.ConclusionOur study showed a wide variation in current practice among pain physicians in treating CRPS with SBs. There is a clear need for evidence-based guidelines on when and how to perform SBs for CRPS.

Objective In this study, we aimed to determine if stellate ganglion block (SGB) could reduce symptoms of posttraumatic stress disorder (PTSD) in comparison with sham therapy in military service members. Methods In a randomized trial in which both participants and assessors were blind, participants with PTSD received either an SGB or a sham procedure. Posttraumatic stress disorder symptoms were measured using the CAPS (Clinician-Administered PTSD Scale) and self-report measures of PTSD, depression, anxiety, and pain. Subjects underwent assessment before the procedure and at 1 week, 1 month, and 3 months after the procedure. Patients receiving sham injections were allowed to cross over to the treatment group, and participants who maintained criteria for PTSD were allowed to receive a second SGB treatment. Results Posttraumatic stress disorder, anxiety, and depression scores all showed improvement across time, but there was no statistically or clinically relevant difference in outcomes between the active and control groups. Individuals who crossed over from sham treatment to SGB similarly showed no greater improvement with the SGB treatment. Improvement in CAPS was greater with a second SGB treatment than after the first treatment. Conclusions Although previous case series have suggested that SGB offers an effective intervention for PTSD, this study did not demonstrate any appreciable difference between SGB and sham treatment on psychological or pain outcomes. Future studies should examine if differences in treatment methods or patient population could allow individuals with PTSD to benefit from SGB, but current evidence does not support widespread or indiscriminant clinical use of the procedure for PTSD.

Background and Objectives The most common techniques to perform stellate ganglion blocks (SGBs) are the blind C6 approach and the fluoroscopic-controlled paratracheal C7 approach, both after manual dislocation of the large vessels. Complications due to vascular or esophageal puncture have been reported. The goal of this ultrasound imaging study was to determine how frequently hazardous structures are located along the needle path of conventional SGB and to determine the influence of the dislocation maneuver on their position. Methods Sixty volunteers were examined on both sides. The presence of the esophagus, vertebral artery, and other arteries located within the needle path of an SGB at the C6 and C7 levels was determined before and during the dislocation maneuver. Results On the left side, the esophagus was located along the needle path in 22 and 39 of 60 cases at the C6 and C7 levels, respectively, and remained there in 10 and 22 of 60 cases during dislocation. The esophagus appeared in the needle path during dislocation from a previously safe location in 5 and 8 of these cases at the C6 and C7 locations, respectively. The vertebral artery was located in the needle path in a range of 2 to 8 of 60 cases without impact of dislocation on its position. Other arteries were located in the needle path in the range of 10 to 17 of 60 cases with a slight decrease during dislocation. Conclusions The esophagus and relevant arteries were frequently located in the needle path of conventional SGBs. The dislocation maneuver had a partial impact on moving these structures away from the target and may increase left-sided esophageal puncture risk in certain individuals. Ultrasound (US) imaging is expected to improve the safety of SGB, but it will require clinical trials to confirm this expectation.

Background and Objectives: The goal of this study was to compare tissue blood flow at various sites before and after stellate ganglion block (SGB) and to discuss the redistribution of tissue blood flow after SGB. Methods: We studied 16 male Japanese white rabbits. For SGB, the tip of a 26-gauge needle was placed on the left transverse process of the cervical vertebra, 1 to 2 mm caudal to the cricoid cartilage. Either 0.2 mL of 1% lidocaine (lidocaine group) or normal saline solution (saline group) was injected. In the lidocaine group, data were recorded immediately before SGB and at the time when the maximal change in the common carotid arterial blood flow was observed after SGB. In the saline group, data were recorded immediately before SGB and 3 minutes after SGB. Observed variables were blood pressure, heart rate, common carotid arterial blood flow, tongue mucosal blood flow, mandibular bone marrow blood flow (BBF), masseter muscle blood flow (MBF), quadriceps muscle blood flow, liver blood flow, and renal blood flow. Results: Common carotid arterial blood flow, tongue mucosal blood flow, BBF, and MBF on the block side were increased, whereas BBF and MBF on the nonblock side and quadriceps muscle blood flow, liver blood flow, and renal blood flow were decreased after SGB in the lidocaine group. Conclusions: These results indicate that lower limb and visceral blood flow as well as blood flow on the nonblock side are redistributed to the block side after SGB. Redistribution from peripheral tissue may have a more important role than that of visceral blood flow redistribution after SGB.

Background and Objectives: Although the stellate ganglion is located anteriorly to the first rib, anesthetic block is routinely performed at the C6 level. Ultrasonography allegedly improves accuracy of needle placement and spread of injectate. The technique is relatively new, and the optimal approach has not been determined. Moreover, the location of the cervical sympathetic trunk relative to the prevertebral fascia is debatable. Methods: Three-dimensional sonography was performed on 10 healthy volunteers, and image reconstruction was completed. On the basis of analysis of pertinent anatomy, a lateral trajectory for needle placement was simulated. Accuracy was tested by injection of methylene blue in cadavers. A clinical validation study was then conducted. A block needle was inserted according to the predetermined lateral path, and 5 mL of a mixture of bupivacaine and iohexol was injected. Spread of the contrast agent was verified fluoroscopically. Results: Image reconstruction revealed that the cervical sympathetic trunk is located posterolaterally to the prevertebral fascia on the surface of the longus colli muscle. The mean anteroposterior width of the muscle at the C6 level was 11 mm. The lateral approach does not interfere with any visceral or nerve structures. Anatomic dissection in cadavers confirmed entirely subfascial spread of the dye and staining of the sympathetic trunk. The contrast agent spread was seen in all patients between the C4 and T1 levels in a typical prevertebral pattern. Conclusions: This study revealed that, at the C6 level, the cervical sympathetic trunk lies entirely subfascially. Subfascial injection via the lateral approach ensures reliable spread of a solution to the stellate ganglion.

Background and Objectives: The longus colli (LC) muscle is an important structure of the anterior cervical spine and has a critical role in stellate ganglion block. This technique involves withdrawing the needle to locate its port for injection above the anterior surface of the LC muscle; however, its exact thickness at the C5, C6, and C7 levels has not been measured. The aim of this anatomic and magnetic resonance-supported study was to evaluate the thickness of the LC muscle at these levels from the anterior tubercle of each vertebra toward the vertebral body at 5-, 10-, and 15-mm distances to provide precise anatomic data for stellate ganglion block. Methods: Ten cadavers, 60 vertebral body specimens, and cervical magnetic resonance imaging (MRI) scans of 40 adult patients were used for measurements. Results: The main findings of this study are that the thickness of the LC muscle varies between 5.0 and 10.0 mm at C6 and C7 in cadavers and between 8.0 and 10.0 mm in MRI scans. Sex has an important role; MRI scans revealed that male patients have a considerably thicker LC muscle at each vertebral level. Conclusion: We found a highly variable thickness of the LC muscle in anatomic and imaging studies, which may lead to negative block results.

Background and Objectives Stellate ganglion block is often carried out using palpation of surface landmarks to guide needle placement. However, anatomic variation of the surface landmarks used is common and block failure has been reported in as many as 30% of patients, even when the surface landmarks that guide needle placement can be easily identified. Methods Computed tomography (CT) images of the cervical spine of 70 adult patients were examined to measure the distances in the coronal and sagittal planes between various points on the cricoid cartilage, anterior tubercle, posterior tubercle, and nadir of the vertebral gutter. The width of the tubercle in the caudal and cephalad plane was determined through multiplanar reformatted CT images in 6 randomly chosen patients. Results The mean distance from the lateral margin of the cricoid cartilage laterally to the anterior tubercle was 13 ± 5 mm (range 3-22 mm) in men and 12 ± 3 mm (range 6-22 mm) in women. The mean depth of the anterior tubercle as measured posteriorly from the midpoint of the trachea was 20 ± 4 (range 10-33 mm) in men and 19 ± 4 mm (range 9-33 mm) in women. The maximal and minimal cephalad-caudad dimensions of the transverse process of C6 were 9.3 ± 0.3 mm, and 6.7 ± 0.3 mm, respectively. Conclusions Large variability was observed in the size and location of the landmarks used for needle placement during stellate ganglion block. Placement of the needle medially where the transverse process joins the lateral margin of the vertebral body provides a larger bony target that may potentially provide a safer, more reliable block.

Background and objectives The aim of this study is to examine the effects of head-up tilt (70°) 30 minutes after right or left stellate ganglion block (SGB) on RR interval, QT interval, the rate-corrected QT (QTc) interval, QT dispersion (QTD), and the rate-corrected QT dispersion (QTcD) using computerized measurement. Methods Ten healthy volunteers underwent both right and left SGBs using 7 mL 1% mepivacaine with a 7-day interval between the two blocks. A 12-lead electrocardiogram was monitored to measure parameters before SGB; 30 minutes after SGB (before head-up tilt); and immediately, 5, 10, and 15 minutes after head-up tilt. Results Right SGB induced significant increases in QT interval, QTc interval, QTD, and QTcD from 30 minutes after the block through 15 minutes after head-up tilt. There were significant increases of QT interval, QTc interval, and QTcD between before and immediately after head-up tilt in right SGB. Left SGB induced significant decreases of QT interval and QTc interval from 30 minutes after SGB through 15 minutes after head-up tilt. Left SGB also induced a significant decrease of QTD from immediately after through 10 minutes after head-up tilt. Conclusions Significant increases of QT interval, QTc interval, and QTcD, which are associated with an increased risk of ventricular arrhythmias and cardiac events, occur immediately after head-up tilt in right SGB. However, head-up tilt does not induce increases of QT interval, QTc interval, QTD, and QTcD in left SGB.

Background and Objectives: Prolongation of QT interval and QT dispersion (QTD) may be associated with an increased risk of arrhythmias. This study was designed to investigate the effects of right or left stellate ganglion block (SGB) on RR interval, QT interval, the rate-corrected QT (QTc) interval, QTD and the rate-corrected QTD (QTcD) using computerized measurements. Methods: Ten healthy volunteers underwent both right and left SGBs using 7 mL 1% mepivacaine with a 7-day interval between the 2 blocks. The measurement from the 12-lead electrocardiogram was performed for 60 minutes after SGB. Results: Right SGB induced a significant decrease of RR interval immediately after the block, and significant increases of QT interval, QTc interval, QTD, and QTcD from immediately through 50 minutes after the block ( P [lt ] .01). Left SGB induced a significant decrease of RR interval, and significant increases of QTc interval and QTD immediately after the block ( P [lt ] .01). Left SGB also produced a significant decrease of QT interval from 20 through 50 minutes after the block, and a significant decrease of QTc interval from 30 through 50 minutes after the block ( P [lt ] .05). Conclusions: Right SGB induces increases of the QT interval, QTc interval, QTD, and QTcD, and left SGB induces decreases of the QT interval and QTc interval. Reg Anesth Pain Med 2001;26:539-544.

Background and Objectives: The aim of this study is to clarify the influence of acute cigarette smoking on vasodilation induced by sympathetic block. Methods: We measured mean arterial pressure, heart rate, left brachial artery blood flow (BABF), right femoral artery blood flow (FABF), and plasma catecholamines in dogs to examine the effect of acute cigarette smoking after stellate ganglion block (SGB). The experimental protocol was: (1) Left SGB using 1.0 mL 0.5% mepivacaine without smoking (sham smoking); and (2) left SGB using 1.0 mL 0.5% mepivacaine followed by a single cigarette smoking (nicotine 1 mg) 15 minutes after the block. Results: SGB induced a significant increase of BABF during the study (baseline, 100%; peak at 10 minutes after SGB, 176% ± 9%; P < .05) in sham smoking and a significant decrease of FABF from 10 minutes after the block to 20 minutes after sham smoking (baseline, 100%; bottom at 5 minutes after sham smoking, 82% ± 8%; P < .05). Smoking after SGB induced a significant decrease of BABF 60 minutes after smoking (baseline, 100%; 69% ± 11%; P < .05) and a significant decrease of FABF during the study (baseline, 100%; bottom at 20 minutes after smoking, 74% ± 20%; P < .05). Smoking significantly increased plasma norepinephrine and epinephrine through the study. Conclusions: Sympathetic block induces a significant increase of peripheral blood flow, but smoking produces a significant decrease in the blood flow in the SGB-induced dilated vessels. Reg Anesth Pain Med 2001;26:41-45.

Stellate ganglion block (SGB) leads to vasodilation of the head and neck, as a result of a regional sympathetic blockade. However, in such cases, controversy remains concerning changes in cerebral and extracerebral blood flow in the head. We estimated the effect of SGB on blood flow in the head by measuring the blood flow velocity in cervical vessels, using magnetic resonance imaging and the direct bolus tracking method. This noninvasive method is free from potential artifacts of bones and other connective tissues.Seven adult patients with acute or chronic pain in the head or neck underwent SGBs, using an anterior paratracheal approach with 6-8 mL of 1% mepivacaine (3 right and 4 left SGBs). Blood flow velocity in common carotid and vertebral arteries (CCA and VA) was measured simultaneously before and after SGB, using the direct bolus tracking method.On the side of SGB, blood flow velocity in CCA significantly increased (P.002), whereas velocity in VA was unchanged after SGB. On the side contralateral to the SGB, significant changes in blood flow velocity in CCA and VA were never observed.Blood from the VA flows primarily to cerebral vessels, whereas that from CCA goes to both cerebral and extracerebral vessels. Given the presumed differences in blood flow distribution through the VA and CCA, we assume that the observed CCA blood flow increases, ipsilateral to the SGB, primarily as a result of vasodilation of extracerebral vessels and independent of changes in brain blood flow.

Background and Objectives Delayed onset of airway obstruction following stellate ganglion block (SGB) may be life threatening. We treated a patient who developed a severe airway obstruction caused by a large hematoma several hours after an SGB. Methods A 62-year-old woman suffering from sudden deafness developed dyspnea 2 hours after undergoing her fourth SGB, and evidenced swelling and tenderness in her anterior neck and chest. Her pharyngolaryngeal tissues were edematous, and the glottis was markedly narrowed. Computed tomograms and magnetic resonance images revealed a large soft tissue mass extending from the first cervical vertebra to the diaphragm. Results Surgical tracheotomy was performed to maintain her airway. Swelling of the vocal cord disappeared on the eleventh day after the operation. Conclusions We believe that the SGB needle injured the vertebral artery and caused massive hemorrhage anterior to the cervical vertebra, subsequently inducing pharyngolaryngeal edema by obstructing the venous and lymphatic drainage of the cervical region.

Background and Objectives. Although an increase in skin temperature of the hand implies sympathetic block after stellate ganglion block (SGB), it does not indicate complete sympathetic block unless accompanied by an absence of sweating because skin temperature may increase even with a partial sympathetic block. This study examined the efficacy of the SGB to block sweating in the hand and to determine if the magnitude of temperature change in the hand is predictive of a negative sweat test. Methods. Fifty-nine SGBs were performed in 30 patients (15 women and 15 men) for diagnostic or therapeutic indications. Stellate ganglion block was performed via an anterior paratracheal approach at C6 using 15 mL 0.25% bupivacaine. Skin temperature was measured bilaterally on the index finger. A cobalt blue sweat test was performed bilaterally pre-and post-SGB on the middle finger. Successful sympathetic block after SGB was considered present when: (a) (change in ipsilateral temperature (postblock-preblock)] (Di)-[change in contralateral temperature] (Dc) ≥ 1.5°C; (b) Horner's syndrome present; and (c) sweat test changed from positive to negative. Logistical regression was applied to determine what value of Di − Dc could be used to predict a negative sweat test. Results. Thirty-six percent ( 21 59 ) of blocks met all three criteria. Of the blocks where Di − Dc ≥ 1.5°C, 72% ( 21 29 ) had a negative sweat test post-SGB. Of the blocks where Di − Dc 11 30 ) had a negative sweat test postblock. If Di − Dc ≥ 2.0°C, a negative sweat test could be predicted with 69 ± 12% sensitivity and 85 ± 10% specificity. Conclusions. Stellate ganglion block often fails to increase skin temperature in the ipsilateral more than the contralateral hand. A value of Di − Dc ≥ 2.0°C was a good predictor of a sympathetic block, but was not sufficient to guarantee a complete sympathetic block of the hand after SGB in all cases. An apparently successful SGB as measured by “usual” clinical criteria may not result in a complete sympathectomy of the hand as is often assumed. Therefore, if obtaining a sympathectomy is important for diagnostic or therapeutic purposes, performing a sweat test provides important confirmatory evidence of the genuine success of the sympathetic block.

Background and Objectives Stellate ganglion block can promptly relieve acute herpetic pain (AHP) involving the trigeminal and cervical regions. However, repeated blocks are needed to maintain pain relief in most patients with severe AHP. Because continuous epidural block is easily performed using an indwelling catheter, we compared the effect of high thoracic epidural block with that of stellate ganglion block to relieve moderate-to-severe AHP involving these regions. Methods Six patients received stellate ganglion blocks and seven patients received high thoracic epidural blocks. Six milliliters 1% of mepivacaine was given to each patient. Acute herpetic pain was evaluated before and up to 60 minutes after the blocks, using a visual analog scale (VAS) of pain. Results There was no significant difference in VAS pain scores before the blocks between the groups, but there were significant (P Conclusions High thoracic epidural block was as effective as stellate ganglion block in relieving moderate-to-severe AHP involving the trigeminal and cervical regions.

Objective: This report describes the effects of ganglionic local opioid application (GLOA) in patients with chronic headache and persistent idiopathic facial pain. Case Report: We present 2 patients with chronic headaches and 1 patient with persistent idiopathic facial pain who were refractory to medical treatment. These patients responded well to a series of ganglionic local opioid applications (GLOAs) by administration of buprenorphine. The beneficial effect of GLOA was manifested by a decrease in pain intensity, reduction of pain medications, and improvement in quality of life. Conclusions: These results support the theory of sympathetically mediated pain in the head and face, the presence of opioid receptors on the sympathetic ganglia, and a possible beneficial role of opioids in modulation of this process. To our knowledge, this case series is the first case series in the English literature of the use of GLOA at the stellate ganglion for head-and-face pain.

Background and Objectives. The stellate ganglion can alleviate phantom pain of the upper extremity, possibly because of the presence in it of enkephalin receptors, as has been suggested by experimental and clinical reports. A case is reported in which fentanyl, instead of local anesthetic, was used for stellate ganglion block. Methods. A 49-year-old man with a left below-elbow amputation, presented with probable symptoms of reflex sympathetic dystrophy, pain and temperature changes at the stump, and phantom hand symptoms the English-language literature revealed no reports of the use of fentanyl infiltration of the stellate ganglion was performed for management of this condition. Results. Significant alleviation of pain and sensation of warmth at the stump and in the phantom hand was achieved. Conclusions. Fentanyl infiltration of the stellate ganglion proved to be successful in the management of the pain and temperature sensation changes in the stump and phantom upper extremity.

Background: Sympathetically maintained pain (SMP) can occur in patients with neuropathic pain. Sympathetically maintained pain is frequently diagnosed clinically by assessing the analgesic effect of an appropriate sympathetic block (SB). The diagnostic value of such blocks depends on both the degree of sympathetic activity disruption achieved and its duration without unintentional concomitant sensory block. Methods: This pilot study evaluated the rate of diagnostically valuable SBs performed by experienced anesthesiologists in 19 patients (stellate/thoracic blocks: n = 11, lumbar blocks: n = 12). Monitoring included pain rating before SB; 10 and 30 minutes; and at 1, 3, and 6 hours after SB; bilateral skin temperature 30 minutes before SB through 120 minutes after SB; and detection of bilateral thresholds for cold, warmth, tactile, and vibration stimuli before and after. Results: Ten (43%) of 23 SBs were not eligible for SMP diagnosis (4 had insufficient skin temperature increase; and 6 had cold or tactile detection threshold increases in the painful area). In 11 of the SBs, no significant sensory threshold change was detected; however, 2 individuals demonstrated marked reductions in the cold or tactile sensory thresholds. Sympathetically maintained pain was diagnosed in 3 (25%) of the 12 patients who had at least 1 SB with the required skin temperature increase without concomitant somatosensory block. Conclusions: Sympathetic blocks are useful in the diagnosis of SMP. However, their value is limited by the potential for false positives (unintentional sensory block) or false negatives (insufficient SB). Adequate monitoring of the sympathetic and somatosensory function for a minimum of 90 minutes after the intervention is essential to ensure that a valid diagnosis of SMP is made.

Background and Objectives The chronic intestinal pseudo-obstruction due to visceral myopathy is a disorder resembling bowel obstruction but without mechanical occlusion. Frequently, parenteral nutrition becomes the final palliative treatment. A patient affected with this syndrome for 16 years was suffering causalgic pain provoked by intraveneous perfusion. Stellate ganglion block was requested in the hope of maintaining the perfusion. Methods Stellate ganglion block not only stopped the pain but unexpectedly, it temporarily relieved the pseudo-obstruction symptoms. Two radiofrequency coagulations in the stellate ganglion prolonged the beneficial effects on gastrointestinal transit for more than 3 weeks, after which the symptoms returned. Multidisciplinary and multicenter advice was that further destructive treatments not be attempted. Results Repetitive stellate ganglion blocks with 2 mL of bupivacaine 0.75% restored gastrointestinal function for more than 3 weeks. However, after performance of radiofrequency coagulation, infiltration with bupivacaine was followed by hypermetropia on the right eye of 2 weeks duration. Conclusions The relationship between stellate ganglion block and gastrointestinal function has not been described. This case report does not provide sufficient information to recommend this technique for pseudo-obstruction symptoms. Moreover, the result in this case is a fortuitous observation, lacking a clear scientific explanation. Further study may be warranted.

Background Volumes from 5 to 20 mL of local anesthetic are used for stellate ganglion block. The variation of practice gave us the impetus to investigate the distribution of 3 different volumes of solution. We documented the regions reached by each volume to assess the possibility to reduce the injectate to 5 mL. Materials and Method A total of 42 cadavers (84 halves), fixed by Thiel9s method and on which pulse simulation was performed, were investigated. Of these 84 halves, 28 were injected with 5 mL of contrast (group A), 28 halves with 10 mL (group B), and 28 halves with 20 mL (group C), according to the tissue-displacement method. Immediately after injection, the cadavers were investigated by use of CT scans with a possible 3-dimensional reconstruction. In addition, 4 halves of group A and group B were dissected, and the contrast distribution was determined by photography. Results Group A showed a constant dissemination from C4 to Th2-Th3, without spreading to ventral or lateral regions. In group B, a persistent spread from C4 to Th3 was documented. Ventral and lateral regions were also reached in one third of the specimens. Group C showed a constant dissemination from C3 to Th4-Th5, with additional spread to ventral, lateral, and posterior regions of the neck similar to that in group B. Conclusion The use of 5 mL results in an almost ideal vertical distribution in most of the cadavers, whereas high volumes—20 mL more so than 10 mL—are at risk of spreading extensively in both the vertical direction and also uncontrollably to other regions of the neck.

Background and Objectives The precise fascial space through which the injectate spreads during stellate ganglion block (SGB) remains unclear. Recent studies using magnetic resonance imaging or computed tomography have suggested that the injectate is deposited around and/or within the longus colli muscle during SGB. However, a fascial space, close to the longus colli, is the most likely route of spread. We identified the prevertebral interlaminal space (PVILS), situated between the anterior and posterior laminae of the prevertebral layer of the fascia, as an important route for the spread of the injectate and as a potential pathway to the ganglion. The danger of downward spread of deep infections through this space has previously been recognized. Methods and Results Using the 6th cervical vertebra paratracheal approach technique, we performed experimental SGB with 10 mL latex on donated cadavers. Spreading of latex into the PVILS was observed in 45 of 52 (86.5%) cadavers that had been fixed with formaldehyde after death, and 5 of 8 (62.5%) fresh cadavers. In these experiments, the latex usually reached the ganglion via the PVILS (39 of 45 and 5 of 5, respectively). Moreover, after direct injection into the PVILS, latex reached the ganglion in 13 of a further 19 (68.4%) postmortem-fixed donated cadavers. Conclusion These results suggest that the PVILS plays a critical role in the spread of injectate as well as being a potential pathway to the stellate ganglion during SGB.

It is our hypothesis that stellate ganglion block increases regional blood flow on the blocked side, but does not change cardiac output, suggesting that the corresponding regional blood flow on the contralateral side may decrease, which would be disadvantageous for patients with bilateral sympathetically-maintained pain. The aim of this study is to examine the effect of stellate ganglion block on facial skin blood flow.Skin blood flow on the right and left forehead was measured by a laser blood flowmeter before stellate ganglion block and 15 minutes after the block. The block was performed for 8 outpatients with acute or chronic pain in the head or neck using a 24-gauge needle, 5 mL of 1% mepivacaine, and a paratracheal approach at the C6 transverse process. Time control without the block was obtained with 9 healthy volunteers.All the patients developed the Horner's syndrome on the blocked side, but not on the contralateral side. The facial skin blood flow increased from 7.5 +/- 1.1 mL/min/100 g to 14.5 +/- 1.4 mL/min/100 g on the blocked side (P.01) and from 8.8 +/- 1.2 mL/min/100 g to 12.8 +/- 1.7 mL/min/100 g on the contralateral side (P.05). The healthy volunteers without the block showed no significant change (from 10.1 +/- 0.8 mL/min/100 g to 10.3 +/- 0.7 mL/min/100 g).Our study suggests that stellate ganglion block may increase the contralateral regional skin blood flow.

Clinical evidence suggests that stellate ganglion block (SGB) might modulate the immune system. Little is known, however, about the immunologic effects of SGB. We examined how SGB affected immune functions by analyzing the activation response of lymphocytes during SGB.Twenty-four volunteers were randomly subdivided into three groups. The SGB group (SGB; n = 9) received 6 mL 1% lidocaine at the sixth cervical vertebra (C6) transverse process and showed Horner's sign and elevation of ipsilateral facial and upper limb temperature. The lidocaine group (n = 7) had 6 mL 1% lidocaine injected into subcutaneous tissue at the neck and showed no remarkable clinical effects. The saline group (placebo; n = 8) received 6 mL saline solution injected at approximately the C6 transverse process and showed no remarkable clinical effects. Peripheral blood samples were drawn before and 30 minutes after drug administration. Samples were incubated for 4 hours under the stimulation of mitogen. Using flow cytometry, we measured the de novo expression of CD69, which is one of the initial markers of lymphocyte activation and which reflects the cell activation process. The changes in pre- and post-values were calculated and compared among the three groups.In only the SGB group, the helper T-cell activation was significantly reduced, and the cytotoxic T-cell activation also tended to decrease after SGB.SGB may depress immune system activity for a short time, as reflected in the T-cell activation response.

Stellate ganglion block can promptly relieve acute herpetic pain (AHP) involving the trigeminal and cervical regions. However, repeated blocks are needed to maintain pain relief in most patients with severe AHP. Because continuous epidural block is easily performed using an indwelling catheter, we compared the effect of high thoracic epidural block with that of stellate ganglion block to relieve moderate-to-severe AHP involving these regions.Six patients received stellate ganglion blocks and seven patients received high thoracic epidural blocks. Six milliliters 1% of mepivacaine was given to each patient. Acute herpetic pain was evaluated before and up to 60 minutes after the blocks, using a visual analog scale (VAS) of pain.There was no significant difference in VAS pain scores before the blocks between the groups, but there were significant (P.05) decreases in VAS pain scores for both groups between 10 and 60 minutes after the blocks. There were no significant differences in VAS pain scores between the groups after the blocks.High thoracic epidural block was as effective as stellate ganglion block in relieving moderate-to-severe AHP involving the trigeminal and cervical regions.

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