Correlation Between Temperature Rise after Sympathetic Block and Pain Relief in Patients with Complex Regional Pain Syndrome

Multicenter Prospective Randomized Comparison of Ultrasound-Guided Stellate Ganglion Versus Thoracic Paravertebral Block for Sympathetic Blockade in Chronic Upper Extremity Pain

BACKGROUND

Stellate ganglion block (SGB) is a type of sympathetic block used to relieve pain in the face and upper extremities. However, its effectiveness can be limited by the presence of Kuntz fibers that bypass the stellate ganglion. Thoracic paravertebral block (TPVB) offers an alternative in such cases. We hypothesized that ultrasound (US)-guided TPVB would provide a higher success rate of upper extremity sympathetic blockade than US-guided SGB. Therefore, this prospective randomized study aimed to compare the technical success rates between US-guided TPVB and US-guided SGB and assess clinical outcomes in alleviating upper extremity pain.

METHODS

Patients aged 19 to 85 years diagnosed with chronic upper extremity pain (complex regional pain syndrome and neuropathic pain) were randomly assigned to either the US-guided TPVB group, where they received a 10 mL injection of 1% mepivacaine in the T2 paravertebral space, or the US-guided SGB group, where they received a 5 mL injection of 1% mepivacaine at the C6 level. The primary outcome was the success rate (%) of sympathetic blockade, which was predefined as the difference in temperature change between affected and unaffected hands 20 minutes after the procedure (ΔT difference) of ≥ 1.5°C. Secondary outcomes included comparisons of the ΔT difference (°C), differences in peak systolic velocities (cm/s) of the ipsilateral brachial artery at 20 minutes, and pain intensity at baseline and 20 minutes, 1 week, and 4 weeks after the procedure using an 11-point numerical rating scale (NRS) pain score.

RESULTS

The TPVB group (N = 22/35, 62.9%) showed a higher success rate than the SGB group (N = 13/34, 38.2%; P = .041) in achieving the primary outcome of sympathetic blockade at 20 minutes. The difference in success rates between the 2 groups was 24.6 % (95% confidence interval [CI], -9.0% to 58.2%). The ΔT difference was significantly higher in TPVB than in SGB (2.0°C ±1.5 and 1.1°C ±1.3, respectively; P = .008). The peak systolic velocities at 20 minutes increased in TPVB (P = .005), which was not observed in SGB (P = .325). Pain intensity decreased in both groups 20 minutes after injection (P < .001 in each group), and the TPVB group showed a lower 11-point NRS pain score compared to the SGB group (4.3 ± 2.2 and 5.4 ± 2.4, respectively; P = .038). Pain intensity scores increased to preintervention levels in both groups at 1 week and 4 weeks after the interventions.

CONCLUSIONS

US-guided TPVB had a higher success rate of upper extremity sympathetic blockade than US-guided SGB, with more pronounced immediate postprocedural pain relief.

10. Complex regional pain syndrome

INTRODUCTION

Complex regional pain syndrome (CRPS) is a clinical disorder that can develop following surgery or trauma. Based on the most prominent underlying pathophysiological mechanisms, CRPS can be classified into different subtypes, namely inflammatory, nociplastic/neuropathic, vasomotor, and motor. Depending on the subtype, personalized treatment can be applied. If conservative treatments are insufficient or ineffective, more invasive treatments may be recommended. This article provides an overview of the most recent insights into CRPS and discusses the most common invasive treatments.

METHODS

The literature regarding interventional treatments for CRPS has been systematically reviewed and summarized.

RESULTS

Bisphosphonates are effective in treating the inflammatory subtype, while ketamine can provide pain relief for the nociplastic/neuropathic subtype. Sympathetic blocks are effective in addressing vasomotor disturbances. For patients with refractory symptoms, neurostimulation is a viable option due to its multimechanistic properties for all subtypes. End-of-line motor disturbances may benefit from intrathecal baclofen.

CONCLUSIONS

CRPS is a debilitating condition with an unpredictable course. The effectiveness of treatment varies from patient to patient. When conservative approaches prove insufficient, gradual progression to invasive treatments based on the underlying subtype is recommended.

Evaluation of thoracic sympathetic ganglion block as a predictor for response to ketamine infusion therapy and spinal cord stimulation in patients with chronic upper extremity pain

OBJECTIVE

To investigate the predictive value of thoracic sympathetic ganglion block (TSGB) in response to ketamine infusion therapy (KIT) and spinal-cord stimulation (SCS) in patients with chronic upper-extremity pain including complex regional pain syndrome (CRPS).

DESIGN

Retrospective.

SETTING

Tertiary hospital single-center.

SUBJECTS

Patients who underwent TSGB receiving KIT or SCS within a 3-year window.

METHODS

Positive TSGB outcomes were defined as ≥2 0-10 Numerical Rating Scale (NRS) score reduction at 2 weeks post-procedure. Positive KIT and SCS outcomes were determined by ≥2 NRS score reduction at 2-4 weeks post-KIT and ≥4 NRS score reduction at 2-4 weeks post-SCS implantation, respectively.

RESULTS

Among 207 patients who underwent TSGB, 38 received KIT and 34 underwent SCS implantation within 3 years post-TSGB; 33 patients receiving KIT and 32 patients receiving SCS were included. Among 33 patients who received KIT, 60.6% (n = 20) reported a ≥ 2 0-10 NRS pain-score reduction. Positive response to TSGB occurred in 70.0% (n = 14) KIT responders, significantly higher than that in 30.8% (n = 4) KIT non-responders. Multivariable analysis revealed a positive association between positive responses to TSGB and KIT (OR 7.004, 95% CI 1.26-39.02). Among 32 patients who underwent SCS implantation, 68.8% (n = 22) experienced short-term effectiveness. Positive response to TSGB was significantly higher in SCS responders (45.5%, n = 10) than in non-responders (0.0%). However, there were no associations between pain reduction post-TSGB and that post-KIT or post-SCS.

CONCLUSIONS

A positive response to TSGB is a potential predictor for positive KIT and SCS outcomes among patients with chronic upper-extremity pain, including CRPS.

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.

A proof-of-concept study of ultrasound-guided continuous parasacral ischial plane block for postoperative pain control in patients undergoing total knee arthroplasty

BACKGROUND

Continuous peripheral nerve blocks are widely used for anesthesia and postoperative analgesia in lower limb surgeries. The authors aimed to develop a novel continuous sacral plexus block procedure for analgesia during total knee arthroplasty.

METHODS

The study comprised two stages. In Stage I, the authors built upon previous theories and technological innovations to develop a novel continuous sacral plexus block method, ultrasound-guided continuous parasacral ischial plane block (UGCPIPB) and subsequently conducted a proof-of-concept study to assess its effectiveness and feasibility. Stage II involved a historical control study to compare clinical outcomes between patients undergoing this new procedure and those receiving the conventional procedure.

RESULTS

The study observed a 90% success rate in catheter placement. On postoperative day (POD) 1, POD2, and POD3, the median visual analog scale (VAS) scores were 3 (range, 1.5-3.5), 2.5 (1.6-3.2), and 2.7 (1.3-3.4), respectively. Furthermore, 96.3% of the catheters remained in place until POD3, as confirmed by ultrasound. The study revealed a significant increase in skin temperature and peak systolic velocity of the anterior tibial artery on the blocked side compared with those on the non-blocked side. Complications included catheter clogging in one patient and leakage at the insertion site in two patients. In Stage II, the novel technique was found to be more successful than conventional techniques, with a lower catheter displacement rate than the conventional procedure for continuous sciatic nerve block.

CONCLUSION

UGCPIPB proved to be an effective procedure and safe for analgesia in total knee arthroplasty.

CHINESE CLINICAL TRIAL REGISTRY NUMBER

ChiCTR2300068902.

Effect duration of lumbar sympathetic ganglion neurolysis in patients with complex regional pain syndrome: a prospective observational study

Lumbar sympathetic ganglion neurolysis (LSGN) has been used for long-term pain relief in patients with complex regional pain syndrome (CRPS). However, the actual effect duration of LSGN has not been accurately measured. This prospective observational study measured the effect duration of LSGN in CRPS patients and investigated the relationship between temperature change and pain relief. After performing LSGN, the skin temperatures of both the maximum pain site and the plantar area in the affected and unaffected limbs were measured by infrared thermography, and pain intensity was assessed before and at 2 weeks, 1 month, and 3 months. The median time to return to baseline temperature was calculated using survival analysis. The skin temperature increased significantly at all-time points relative to baseline in both regions (maximum pain site: 1.4 °C ± 1.0 °C, plantar region: 1.28 °C ± 0.8 °C, all P < 0.001). The median time to return to baseline temperature was 12 weeks (95% confidence interval [CI] 7.7-16.3) at the maximum pain site and 12 weeks (95% CI 9.4-14.6) at the plantar area. Pain intensity decreased significantly relative to baseline, at all-time points after LSGN. In conclusion, the median duration of the LSGN is estimated to be 12 weeks.

Effectiveness of acupuncture for pain relief in shoulder-hand syndrome after stroke: a systematic evaluation and Bayesian network meta-analysis

Background

Shoulder-hand syndrome (SHS) is a common complication after stroke, and SHS-induced pain significantly hampers patients' overall recovery. As an alternative therapy for pain relief, acupuncture has certain advantages in alleviating pain caused by SHS after stroke. However, choosing the best treatment plan from a variety of acupuncture options is still a serious challenge in clinical practice. Therefore, we conducted this Bayesian network meta-analysis to comprehensively compare the effectiveness of various acupuncture treatment methods.

Methods

We systematically searched for randomized controlled trials (RCTs) of acupuncture treatment in patients with post-stroke SHS published in PubMed, Embase, Cochrane, and Web of Science until 9 March 2023. We used the Cochrane bias risk assessment tool to assess the bias risk in the included original studies.

Results

A total of 50 RCTs involving 3,999 subjects were included, comprising 19 types of effective acupuncture interventions. Compared to single rehabilitation training, the top three interventions for VAS improvement were floating needle [VAS = -2.54 (95% CI: -4.37 to -0.69)], rehabilitation + catgut embedding [VAS = -2.51 (95% CI: -4.33 to -0.68)], and other multi-needle acupuncture combinations [VAS = -2.32 (95% CI: -3.68 to -0.94)]. The top three interventions for improving the Fugl-Meyer score were eye acupuncture [Meyer = 15.73 (95% CI: 3.4627.95)], other multi-needle acupuncture combinations [Meyer = 12.22 (95% CI: 5.1919.34)], and traditional western medicine + acupuncture + traditional Chinese medicine [Meyer = 11.96 (95% CI: -0.59 to 24.63)].

Conclusion

Multiple acupuncture methods are significantly effective in improving pain and upper limb motor function in post-stroke SHS, with relatively few adverse events; thus, acupuncture can be promoted.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/, CRD42023410957.

Human lumbar sympathetic blockade: An anatomical study to address potential block failure

The lumbar sympathetic block is often used to treat complex regional pain syndrome, but it seems to have a high failure rate. This study seeks anatomical explanations for this apparent failure in order to refine our block procedure. Two simulated sympathetic trunk blocks were carried out on four fresh, cryopreserved unembalmed human cadavers under fluoroscopic control at the L2 vertebral body level, followed by two further simulated blocks at the L4 vertebral body level on the other side. Dye was injected, and the areas were dissected following a specific protocol. We then describe the anatomy and the spread of the dye compared to the spread of the contrast medium on fluoroscopy. The ganglia were differently located at different vertebral levels, and differed among the cadavers. Following this anatomical clarification, we now prefer to perform lumbar sympathetic blocks at the fourth lumbar vertebra level, using an extraforaminal approach at the caudal end of ​​the vertebra, avoiding the anterolateral margin of the vertebral body at the midpoint.