Review of Sympathetic Blocks: Anatomy, Sonoanatomy, Evidence, and Techniques

Thoracic sympathetic ganglion blocks: real-world outcomes in 207 chronic pain patients

BACKGROUND

Thoracic sympathetic ganglion block (TSGB) is a procedure to manage sympathetically maintained upper extremity pain (sympathetically maintained pain). To date, only a few studies have evaluated the clinical effectiveness of TSGB in pain medicine. This study investigated (1) the relationship between technical success of TSGB and pain reduction in patients with chronic upper extremity pain and (2) relevant clinical factors for a positive TSGB outcome.

METHODS

We retrospectively reviewed medical data in 232 patients who received TSGB from 2004 to 2020. Technical success and a positive outcome of TSGB were defined as a temperature increase of ≥1.5°C at 20 min and a pain reduction with ≥2 points on the 11-point Numerical Rating Scale at 2 weeks post-TSGB, respectively. Correlations were assessed using correlation coefficients (R), and multivariable regression model was used to identify factors relevant to TSGB outcomes.

RESULTS

207 patients were ultimately analyzed; among them, 115 (55.5%) patients positively responded to TSGB, and 139 (67.1%) achieved technical success after TSGB. No significant relationship existed between the pain reduction and the temperature increase after TSGB (R=0.013, p=0.855). Comorbid diabetes (OR 4.200) and adjuvant intake (OR 3.451) were positively associated, and psychiatric comorbidity (OR 0.327) and pain duration (OR 0.973) were negatively associated with TSGB outcome.

CONCLUSIONS

We found no significant association between the temperature increase and pain reduction after TSGB. Further studies are warranted to identify significant factors associated with TSGB outcomes in patients with complex regional pain syndrome and neuropathic pain diseases.

Lumbar Sympathetic Block for Treatment of Knee Pain From Synovial Plica Syndrome: A Case Report

Lumbar sympathetic blocks (LSBs) are used to treat sympathetically mediated pain in the lower extremities, kidneys, ureters, and genitals. LSBs use local anesthetic to block the sympathetic system to modulate pain response. In this case report, an avid runner was diagnosed with synovial plica syndrome. His pain was refractory to arthroscopic plica excision, physical therapy, nonsteroidal anti-inflammatory drugs, and intraarticular steroid injections. He received 3 rounds of LSB resulting in significant and sustained pain relief. This case suggests that LSB successfully treated knee pain from synovial plica syndrome and there may be a sympathetic component to this disease state.

Comparison of analgesic effects of percutaneous and transthoracic intercostal nerve block in video-assisted thoracic surgery: a propensity score-matched study

BACKGROUND

This study aimed to compare the analgesic efficacy of transthoracic intercostal nerve block (TINB) and percutaneous intercostal nerve block (PINB) for video-assisted thoracic surgery (VATS) using a retrospective analysis.

METHODS

A total of 336 patients who underwent VATS between January 2021 and June 2022 were reviewed retrospectively. Of the participants, 194 received TINB and were assigned to the T group, while 142 patients received PINB and were assigned to the P group. Both groups received 25 ml of ropivacaine via TINB or PINB at the end of the surgery. The study measured opioid consumption, pain scores, analgesic satisfaction, and safety. Propensity score matching (PSM) analysis was performed to minimize selection bias due to nonrandom assignment.

RESULTS

After propensity score matching, 86 patients from each group were selected for analysis. The P group had significantly lower cumulative opioid consumption than the T group (p < 0.01). The Visual Analogue Scale (VAS) scores were lower for the P group than the T group at 6 and 12 h post-surgery (p < 0.01); however, there was no significant difference in the scores between the two groups at 3, 24, and 48 h (p > 0.05). The analgesic satisfaction in the P group was higher than in the T group (p < 0.05). The incidence of back pain, nausea or vomiting, pruritus, dizziness, and skin numbness between the two groups was statistically insignificant (p > 0.05).

CONCLUSION

The study suggests that PINB provides superior analgesia for patients undergoing thoracic surgery compared to TINB without any extra adverse effects.

Analgesic Efficacy of Intraoperative Superior Hypogastric Plexus (SHP) Block during Abdominal Hysterectomy: A Systematic Review and Meta-Analysis of Controlled Trials

Background and Objectives: Abdominal hysterectomy is a major surgery that is often associated with pronounced postsurgical pain. The objective of this research is to conduct a systematic review and meta-analysis of all randomized controlled trials (RCTs) and nonrandomized comparative trials (NCTs) that have surveyed the analgesic benefits and morbidity of intraoperative superior hypogastric plexus (SHP) block (intervention) compared with no SHP block (control) during abdominal hysterectomy. Materials and Methods: The Cochrane Central Register of Controlled Trials (CENTRAL), Google Scholar, Web of Science, PubMed, Scopus, and Embase were searched from inception until 8 May 2022. The Cochrane Collaboration tool and Newcastle-Ottawa Scale were used to evaluate the risk of bias of RCTs and NCTs, respectively. In a random effects mode, the data were pooled as risk ratio (RR) or mean difference (MD) with 95% confidence interval (CI). Results: Five studies (four RCTs and one NCT) comprising 210 patients (SHP block = 107 and control = 103) were analyzed. The overall postsurgical pain score (n = 5 studies, MD = -1.08, 95% CI [-1.41, -0.75], p < 0.001), postsurgical opioid consumption (n = 4 studies, MD = -18.90 morphine milligram equivalent, 95% CI, [-22.19, -15.61], p < 0.001), and mean time to mobilization (n = 2 studies, MD = -1.33 h, 95% CI [-1.98, -0.68], p < 0.001) were significantly decreased in the SHP block group contrasted with the control arm. Nevertheless, there was no significant variance between both arms regarding operation time, intraoperative blood loss, postsurgical NSAID consumption, and hospital stay. There were no major side effects or sympathetic block-related aftermaths in both groups. Conclusions: During abdominal hysterectomy and receiving perioperative multimodal analgesia, the administration of intraoperative SHP block is largely safe and exhibits better analgesic effects compared to cases without administration of SHP block.

Use of thoracoscopy for thoracic sympathetic nerve block in primary hyperhidrosis

Thoracic sympathetic nerve block (TSNB) has been widely used in the treatment of neuropathic pain. To reduce block failure rates, TSNB is assisted with several modalities including fluoroscopy, computed tomography, and ultrasonography. The present study describes our experience assessing the usefulness of thoracoscopy in TSNB for predicting compensatory hyperhidrosis before sympathectomy in primary hyperhidrosis. From September 2013 to October 2021, TSNB was performed under local anesthesia using a 2-mm thoracoscope in 302 patients with severe primary hyperhidrosis. Among the 302 patients, 294 were included for analysis. The target level of TSNB was T3 in almost all patients. The mean procedure time was 21 min. Following TSNB, the mean temperature of the left and right palms significantly changed from 31.5 to 35.3 °C and from 31.5 to 34.8 °C, respectively. With TSNB, primary hyperhidrosis was relieved in all patients. Pneumothorax occurred in six patients, in which no chest tube insertion was required. One patient developed hemothorax and was discharged the next day after small-bore catheter drainage. Transient ptosis developed in 10 patients and improved within a day in all patients. Our experiences showed that thoracoscopic TSNB is accurate, safe, and feasible to block the thoracic sympathetic nerve in patients with severe primary hyperhidrosis.

Subfascial versus extrafascial ultrasound-guided stellate ganglion block in patients with post-mastectomy sympathetically mediated pain: A randomized clinical trial

Background

Despite being a well-described intervention, the optimal anatomical approach to perform a stellate ganglion block (SGB) has been disputed. We compared the subfascial and extrafascial ultrasound-guided (USG) SGB.

Methods

A randomised clinical trial was conducted, consisting of 50 patients in two groups. Group I received SGB via the subfascial approach while Group II received an SGB via the extrafascial approach. The primary endpoint was successful sympathetic blockade (as indicated by a measured temperature rise of ≥2°C). Secondary endpoints included analgesic efficiency (extent of early onset of pain relief as indicated by >50% improvement in Visual Analogue Scale (VAS) score at 300's post-procedure); occurrence of Horner's syndrome; extent of local anaesthetic distribution; and adverse events.

Results

The mean increase in sympathetic blockade was significantly higher in the subfascial group (2.6 ± 0.6°C; p = .003). Analgesic efficacy was also significantly higher in the subfascial group (p < .001). The difference in the average dermatomal spread of local anaesthetic down to T2 and up to C4 between the groups was also statistically significant (p = .021 and p = .019, respectively).

Conclusions

The degree of temperature rise, pain relief and occurrence of Horner's syndrome were higher in the subfascial than the extrafascial group. The subfascial approach to SGB, with a limited volume of local anaesthetic agent, is a more reliable technique when compared to the extrafascial approach.

Efficacy of the lumbar sympathetic ganglion block in lower limb pain and its application prospects during the perioperative period

The sympathetic nervous system is involved in the physiological pathogenesis of many different types of chronic pain. Sympathetic blocks can interrupt the reflex control system by intercepting the noxious afferent fibers accompanying autonomic nerves, resulting in changes in peripheral or central sensory processing. A lumbar sympathetic ganglion block (LSGB), as a treatment method, refers to the injection of nerve blockers into the corresponding lumbar sympathetic nerve segments, usually requiring imaging assistance (CT, X-ray, ultrasound) to guide. At present, LSGB has been widely used in the clinical treatment of lower limb pain, such as neuropathic pain, lower limb ischemic pain, and so on. Its mechanism of action may be through inhibiting sympathetic nerve activity and dilating blood vessels, thereby alleviating pain and inhibiting stress response. However, there are few reports of LSGB during the perioperative period, especially in postoperative pain and gastrointestinal function. Therefore, by studying the literature about LSGB-related studies, this article reviews the anatomy of the lumbar sympathetic nerve (LSN), with its clinical application and possible mechanism. We reviewed the analgesic effect of LSGB in patients with lower limb pain and postoperative pain and the potential application prospects in the recovery of gastrointestinal function, finally providing a reference for its clinical application.

Stellate ganglion block as an intervention in refractory eosinophilic granulomatosis with polyangiitis: a case report

Background

Eosinophilic granulomatosis with polyangiitis (EGPA) is a rare vasculitis. Although glucocorticoid therapy with or without immunosuppressants leads to remission in the majority of cases, most EGPA patients remain dependent on glucocorticoid therapy and experience frequent relapses. Here, we report a case of refractory EGPA which responded to stellate ganglion blocks (SGBs).

Case presentation

A 32-year-old woman with aggravated wheezing, purpura, numbness of multiple fingers, and epigastric and abdominal pain was referred to our clinic. Laboratory and radiographic studies led to the diagnosis of EGPA. After an initial favorable response to glucocorticoid and immunosuppressant therapy, she experienced a relapse during a glucocorticoid taper. We found that SGB brought symptomatic relief and impeded disease progression. The mechanism of action of SGB on EGPA is undetermined, but may be related to vasodilation, immune modulation, and central nervous system regulation.

Conclusions

This report not only proposes a novel treatment modality for EGPA, but also provides a clinical reference point for further in-depth studies of SGB in multiple immune-linked disorders.

Efficacy of ganglion impar block on vulvodynia: Case series and results of mid- and long-term follow-up

RATIONALE

Vulvodynia is a common chronic gynecological disease that affects approximately 16% of women, although it is rarely diagnosed. However, no known effective treatment exists. The etiology of vulvodynia is unknown and may be heterogeneous and multifactorial, so it is difficult-if not impossible-to improve this condition using 1 treatment method. Reports have shown that vulvodynia has an element of neuropathic pain. Although the role of the sympathetic nervous system in neuropathic pain is controversial, sympathetic nerve blocks have long been used to treat patients with chronic pain giving good results. A ganglion impar block (GIB), a sympathetic nerve block technique, may effectively manage pain and discomfort in patients with vulvodynia.

PATIENT CONCERNS

Four patients suffering from chronic vulvar pain for 6 months-10 years were referred by gynecologists. The gynecologists could not identify the cause of the chronic vulvar pain, and symptoms were not improving by conservative therapy with medication. Patients complained of various chronic vulvar pain or discomfort. The initial visual analog scale (VAS) scores were 8 or 9 out of 10, and Leeds assessment of neuropathic symptoms and signs pain scale score was more than 12 out of 24. The review of gynecological medical records confirmed whether they showed allodynia during the cotton swab test and hyperalgesia to pin-prick test.

DIAGNOSES

All patients were diagnosed with vulvodynia.

INTERVENTIONS

All patients were treated with a GIB, once in 2 patients, 3 times in 1 patient, and 4 times (1 alcoholic neurolysis) in the other patient, under fluoroscopic guidance.

OUTCOMES

After the procedures, the VAS score and the leeds assessment of neuropathic symptoms and signs (LANSS) pain scale score were decreased to less than 2 and 5, respectively, in all patients. Follow-up observations for 6 months-2 years revealed that 2 patients' symptoms entirely or nearly entirely improved and did not require further treatment. The pain of the remaining patients were well controlled with medications only.

LESSONS

GIB is a good treatment option for patients suffering from chronic pain and discomfort caused by vulvodynia.

The Use of L2 and L3 Lumbar Sympathetic Blockade for Cancer-Related Pain, an Experience and Recommendation in the Oncologic Population

OBJECTIVE

The sympathetic nervous system has a recognized role in transmission of pain, and the lumbar sympathetic blockade is intended to provide analgesia. We share our experiences of lumbar sympathetic blockade in the treatment of cancer-related pain.

METHODS

We performed a retrospective analysis of patients with cancer-related pain in the back, abdomen, pelvis, or legs treated at Memorial Sloan Kettering Cancer Center between 2000 and 2018 undergoing lumbar sympathetic blockade at L2 or L3. Blocks were accomplished by injection of local anesthetic or local anesthetic with steroid under fluoroscopy. We measured numerical rating scale scores, percent relief, and relief time. The primary end point was defined as "effective" or "ineffective" pain relief. Effective pain relief was defined as ≥30% relief for at least one day.

RESULTS

We identified 124 data points of lumbar sympathetic blockade at L2 or L3, of which 57 were with complete data and used for analysis. Peri-injection, 42 data points had active disease whereas 15 were in remission. Lumbar sympathetic blockade was 67% effective in the back pain cohort, 82% effective in the abdominopelvic pain cohort, and 75% effective in the leg pain cohort. Seventeen data points went on to neurolysis, two to neuromodulation, and eight to intrathecal pump implantation.

CONCLUSIONS

Lumbar sympathetic blockade is effective for back, abdominopelvic, and leg pain related to cancer and its treatments. Future research should be aimed at refining its role within multimodal pain management.

Regional Techniques and Interventions for Intractable Neuropathic Pain

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Ultrasound-Guided Thoracic Paravertebral Block as a Sympathetic Blockade for Upper Extremity Neuropathic Pain: A Prospective Pilot Study

Purpose

Ultrasound-guided thoracic paravertebral block (US-TPVB) is considered a treatment option for the management of acute pain in various pain-related conditions. We conducted a prospective pilot study to evaluate the possibility of US-TPVB as a sympathetic blockade in patients with neuropathic pain disorders in the upper extremities.

Patients and Methods

A total of 12 patients underwent US-TPVB between the T2 and T3 paravertebral space with 10 mL of 1% mepivacaine. The temperature change (°C) before and after the procedure was compared between the ipsilateral and contralateral hands. We counted the proportion of patients showing a temperature increase ≥1.5°C and compared a change in the pain intensity before and after the procedure.

Results

The median increase in the temperature change between the ipsilateral and contralateral hands was 1.54°C (interquartile range, 1.28–2.20). There were seven patients (58.3%) who showed a temperature difference ≥1.5°C between both hands after the US-TPVB. Eleven patients (91.7%) reported a reduction in pain according to the score on the 11-point numerical rating scale. No serious complications relevant to the procedure were reported.

Conclusion

US-TPVB could be a useful technique for sympathetic blockade in patients with upper extremity pain.

NPY stimulates cholesterol synthesis acutely by activating the SREBP2-HMGCR pathway through the Y1 and Y5 receptors in murine hepatocytes

AIMS

The development of non-alcoholic fatty liver disease (NAFLD) is partially attributed to disturbance in cholesterol metabolism and sympathetic overactivity. Excessive levels of the sympathetic neurotransmitter neuropeptide Y (NPY) positively correlated with both NAFLD and cholesterol accumulation. We wanted to determine, for the first time, whether NPY promotes cholesterol accumulation directly in hepatocytes and elucidate the underlying mechanism.

MAIN METHODS

In vivo, NPY was injected through the hepatic portal vein into SD rats. One hour later, serum and liver tissues were collected. In vitro, BRL-3A hepatocytes were treated with NPY, and with Y1, Y2, Y5, receptor antagonists as well as with extracellular signal-regulated protein kinase 1 and 2 (ERK1/2) antagonist, respectively. Cholesterol content was measured by coupled enzyme method. Precursor sterol-regulatory element binding protein 2 (pSREBP2), mature SREBP2 (mSREBP2), HMG-CoA reductase (HMGCR), ERK1/2, pERK1/2, cAMP-dependent protein kinase (PKA), and pPKA protein expression levels were examined by western blotting.

KEY FINDINGS

In rats, intraportal vein injection of NPY activates pSREBP2, mSREBP2, and HMGCR protein expression, and induces hepatic cholesterol accumulation. In BRL-3A cells, we observed that NPY increases cholesterogenic protein expression and cholesterol synthesis through Y1 and Y5 receptors. This effect is mediated by the activation of the ERK1/2 signaling pathway.

SIGNIFICANCE

We demonstrated, for the first time, that NPY can activate the cholesterogenic pathway and elucidated the underlying mechanism. Thus, NPY and NPY receptors might be new targets for the treatment of NAFLD and dyslipidemia.

[The effect of thoracic paravertebral block on seroma reduction in breast surgery - a randomized controlled trial]

BACKGROUND

Increasing number of patients are being operated because of breast cancer. Seroma is the most common problem that occurs after surgery that increases morbidity. For postoperative pain management, Thoracic Paravertebral Block (TPVB) has long been considered the gold standard technique. With performing TPVB, sympathetic nerves are also blocked.

OBJECTIVE

With this study, we aimed to search the effect of TPVB on seroma reduction in patients who undergo mastectomy and axillary node dissection surgery.

METHODS

Forty ASA I-II female patients aged 18-65, who were scheduled to go under elective unilateral mastectomy and axillary lymph node resection were included to the study. Patients were randomized into two groups as TPVB and control group. Ultrasound guided TPVB with 20 mL 0.25% bupivacaine was performed at T1 level preoperatively to the TPVB group patients. All patients were provided with i.v. patient-controlled analgesia device. Seroma formation amounts, morphine consumptions and Numeric Rating Scale (NRS) scores for pain were recorded 24^th hour postoperatively.

RESULTS AND CONCLUSIONS

Mean seroma formation at postoperative 24^th hour was 112.5±53.3 mL in the control group and 74.5±47.4 mL in the TPVB group (p=0.022). NRS scores were similar between two groups (p=0.367) at postoperative 24^th hour but mean morphine consumption at postoperative 24^th hour was 5.6±4 mg in the TPBV group, and 16.6±6.9 mg in the control group (p <0.001). TPVB reduces the amount of seroma formation while providing effective analgesia in patients who undergo mastectomy and axillary lymph node removal surgery.

Bi-national survey of Korea and Japan related to the injection site for ultrasound-guided stellate ganglion blocks and anatomic comparisons using cadaver dissection

The aims of this study were to investigate the current clinical practice of ultrasound (US)-guided stellate ganglion block (SGB) using a bi-national survey of Korea and Japan, and to clarify the anatomical relation of the cervical sympathetic trunk with the prevertebral fascia at the level of cervical vertebrae. The current clinical practice of US-guided SGB in Korea and Japan was investigated using an Internet survey, which received 206 (10.2%) replies from Korea and 97 (8.8%) replies from Japan. The survey questionnaire addressed the actual clinical practice for US-guided SGB, including where the tip of the injection needle is placed. Additionally, 16 half necks of 8 embalmed cadavers were used in an anatomical study. An in-plane needle approach technique and administering 5 ml of local anesthetic were preferred in both countries. However, the type of local anesthetic differed, being lidocaine in Korea and mepivacaine in Japan. The final position of the needle tip also clearly differed in an US image, being predominantly positioned above the prevertebral fascia in Korea (39.3%) and under the prevertebral fascia in Japan (59.8%). In all of the anatomic dissections, the cervical sympathetic trunk was over the prevertebral fascia at the level of the sixth vertebra and under the prevertebral fascia at the level of the seventh vertebra. These results are expected to improve the knowledge on the current clinical practice and to suggest future studies.

The effect of thoracic paravertebral block on seroma reduction in breast surgery – a randomized controlled trial

Background

Increasing number of patients are being operated because of breast cancer. Seroma is the most common problem that occurs after surgery that increases morbidity. For postoperative pain management, Thoracic Paravertebral Block (TPVB) has long been considered the gold standard technique. With performing TPVB, sympathetic nerves are also blocked.

Objective

With this study, we aimed to search the effect of TPVB on seroma reduction in patients who undergo mastectomy and axillary node dissection surgery.

Methods

Forty ASA I–II female patients aged 18–65, who were scheduled to go under elective unilateral mastectomy and axillary lymph node resection were included to the study. Patients were randomized into two groups as TPVB and Control group. Ultrasound guided TPVB with 20 mL 0.25% bupivacaine was performed at T1 level preoperatively to the TPVB group patients. All patients were provided with i.v. patient-controlled analgesia device. Seroma formation amounts, morphine consumptions and Numeric Rating Scale (NRS) scores for pain were recorded 24th hour postoperatively.

Results and conclusions

Mean seroma formation at postoperative 24th hour was 112.5 ± 53.3 mL in the control group and 74.5 ± 47.4 mL in the TPVB group (p = 0.022). NRS scores were similar between two groups (p = 0.367) at postoperative 24th hour but mean morphine consumption at postoperative 24th hour was 5.6 ± 4 mg in the TPBV group, and 16.6 ± 6.9 mg in the control group (p < 0.001). TPVB reduces the amount of seroma formation while providing effective analgesia in patients who undergo mastectomy and axillary lymph node removal surgery.

Complications associated with stellate ganglion nerve block: a systematic review

Stellate ganglion nerve blockade (SGNB) is a vital tool in our armamentarium for the treatment of various chronic pain syndromes. SGNB can be performed using the traditional landmark-based approach, or with image guidance using either fluoroscopy or ultrasound. In this review, we systematically analyzed reported SGNB-related complications between 1990 and 2018. Seven databases were queried for SGNB between January 1, 1990 and November 27, 2018. Search results of the complications associated with SGNB were reported as per the Preferred Reporting Items for Systematic Reviews and Meta-Analyses recommendations. Out of a total of 1909 articles, 67 articles met our inclusion criteria, yielding 260 cases with adverse events. In 134 of the 260 (51.5%) cases, SGNB was performed with image guidance. Sixty-four (24.6%) and 70 (26.9%) of the complication cases reported the use of ultrasound and fluoroscopy guidance, respectively. One hundred and seventy-eight (68.4%) patients had medication-related or systemic side effects, and 82 (31.5%) had procedure-related or local side effects. There was one report of death due to massive hematoma leading to airway obstruction. There was one case report of quadriplegia secondary to pyogenic cervical epidural abscess and discitis following an SGNB. Complications following SGNB have been reported with both landmark-based techniques and with imaging guidance using fluoroscopy or ultrasound. In our systematic review, most adverse events that were reported occurred during or shortly after SGNB. Vigilance, American Society of Anesthesiologists standard monitors for conscious sedation, and accessibility to resuscitation equipment are vital to the safe performance of SGNB.