Change in pulse transit time in the lower extremity after lumbar sympathetic ganglion block: an early indicator of successful block

Retrospective Evaluation of the Effect of Lumbar Sympathetic Blockade on Pain Scores, Fontaine Classification, and Collateral Perfusion Status in Patients with Lower Extremity Peripheral Arterial Disease

Background and Objectives: The aim of this retrospective study was to evaluate the effect of lumbar sympathetic block (LSB) on pain scores, Fontaine Classification, and collateral perfusion status in patients with lower extremity peripheral artery disease (PAD), in whom revascularization is impossible. Material and Methods: Medical records of 21 patients with PAD who underwent LSB with a combination of local anesthetics, steroids, and patient follow-up forms containing six-month follow-ups between January 2020 and March 2021 were retrospectively reviewed. Numeric Rating Scale (NRS), Pain Detect Questionnaire (PDQ) scores, Fontaine Classification Stages, and collateral perfusion status (collateral diameter and/or development of neovascularization) evaluated by arterial color Doppler Ultrasound (US) from the medical records and follow-up forms of the patients were reviewed. Results: NRS and PDQ scores were significantly lower, and regression of the Fontaine Classification Stages was significantly better after the procedure at the first, third, and sixth month than at the baseline values (p < 0.001). Only four patients (19%) had collaterals before the procedure. An increase in the collateral diameter after LSB was noted in three out of four patients. Before the procedure, 17 patients had no prominent collateral. However, in thirteen of these patients, after LSB, neovascularization was detected during the six-month follow-up period (three patients in the first month, seven patients in the third month, and thirteen patients in the sixth month). The number of patients evolving neovascularization after LSB was found to be statistically significant at the third and sixth months compared to the initial examination (p < 0.001). Conclusions: LSB with the use of local anesthetic and steroids in patients with lower extremity PAD not only led to lower NRS and PDQ scores, but also resulted in regressed Fontaine Classification Stages and better collateral perfusion status.

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.

Skin Temperature Assessment During Lumbar Sympathetic Blocks by Infrared Thermography

Complex Regional Pain Syndrome (CRPS) is a pain disorder that can be triggered by injuries or surgery affecting most often limbs. Its multifaceted pathophysiology makes its diagnosis and treatment a challenging work. To reduce pain, patients diagnosed with CRPS commonly undergo sympathetic blocks which involves the injection of a local anesthetic drug around the nerves. Currently, this procedure is guided by fluoroscopy which occasionally is considered as little accurate. For this reason, the use of infrared thermography as a technique of support has been considered.In this work, thermal images of feet soles in patients with lower limbs CRPS undergoing lumbar sympathetic blocks were recorded and evaluated. The images were analyzed by means of a computer-aided intuitive software tool developed using MATLAB. This tool provides the possibility of editing regions of interest, extracting the most important information of these regions and exporting the results data to an Excel file.Clinical Relevance- The final purpose of this work is to value the potential of infrared thermography and the analysis of its images as an intraoperatory technique of support in lumbar sympathetic blocks in patients with lower limbs CRPS.

Quantitative Analysis of Real-Time Infrared Thermography for the Assessment of Lumbar Sympathetic Blocks: A Preliminary Study

Lumbar sympathetic blocks (LSBs) are commonly performed to treat pain ailments in the lower limbs. LSBs involve injecting local anesthetic around the nerves. The injection is guided by fluoroscopy which is sometimes considered to be insufficiently accurate. The main aim was to analyze the plantar foot skin temperature data acquired while performing LSBs in patients with complex regional pain syndrome (CRPS) affecting the lower limbs. Forty-four LSBs for treating lower limb CRPS in 13 patients were assessed. Pain medicine physicians visualized the infrared thermography (IRT) video in real time and classified the performance depending on the observed thermal changes within the first 4 min. Thirty-two percent of the cases did not register temperature variations after lidocaine was injected, requiring the needle to be relocated. Differences between moments are indicated using the 95% confidence intervals of the differences (CI 95%), the Cohen effect size (ES) and the significance (p value). In successful cases, after injecting lidocaine, increases at minute 7 for the mean (CI 95% (1.4, 2.1 °C), p < 0.001 and ES = 0.5), at minute 5 for maximum temperature (CI 95% (2.3, 3.3 °C), p < 0.001 and ES = 0.6) and at minute 6 for SD (CI 95% (0.2, 0.3 °C), p < 0.001 and ES = 0.5) were observed. The results of our preliminary study showed that the measurement of skin temperature in real time by infrared thermography is valuable for assessing the success of lumbar sympathetic blocks.

Real-Time Monitoring of Blood Pressure Using Digitalized Pulse Arrival Time Calculation Technology for Prompt Detection of Sudden Hypertensive Episodes During Laryngeal Microsurgery: Retrospective Observational Study

Background

Laryngeal microsurgery (LMS) is often accompanied by a sudden increase in blood pressure (BP) during surgery because of stimulation around the larynx. This sudden change in the hemodynamic status is not immediately reflected in a casual cuff-type measurement that takes intermittent readings every 3 to 5 min.

Objective

This study aimed to investigate the potential of pulse arrival time (PAT) as a marker for a BP surge, which usually occurs in patients undergoing LMS.

Methods

Intermittent measurements of BP and electrocardiogram (ECG) and photoplethysmogram (PPG) signals were recorded during LMS. PAT was defined as the interval between the R-peak on the ECG and the maximum slope on the PPG. Mean PAT values before and after BP increase were compared. PPG-related parameters and the correlations between changes in these variables were calculated.

Results

BP surged because of laryngoscopic manipulation (mean systolic BP [SBP] from 115.3, SD 21.4 mmHg, to 159.9, SD 25.2 mmHg; P<.001), whereas PAT decreased significantly (from mean 460.6, SD 51.9 ms, to 405.8, SD 50.1 ms; P<.001) in most of the cases. The change in SBP showed a significant correlation with the inverse of the PAT (r=0.582; P<.001). Receiver-operating characteristic curve analysis indicated that an increase of 11.5% in the inverse of the PAT could detect a 40% increase in SBP, and the area under the curve was 0.814.

Conclusions

During LMS, where invasive arterial catheterization is not always possible, PAT shows good correlation with SBP and may, therefore, have the potential to identify abrupt BP surges during laryngoscopic manipulations in a noninvasive manner.

[Effect of bilateral superior cervical sympathetic ganglion occlusion on pathological process of aortic dissection and its mechanism]

OBJECTIVE

To investigate the effect of bilateral superior cervical sympathetic ganglion occlusion (SCG) on aortic dissection and its possible mechanism.

METHODS

Forty-five SD rats were randomly divided into three groups with 15 in each:blank control group, sham operation group and SCG group. β-aminopropione (666 mg·kg-1·d-1) was given by subcutaneous injection for 4 weeks to establish the aortic dissection model. Rats in SCG group were given SCG before the injection of β-aminopropione. Blood pressure and heart rate of the rats were monitored using noninvasive tail artery blood pressure measuring instrument; sympathetic activity was monitored using drug block method; the structure of aortic wall was observed using HE staining; collagen fibers in aortic wall was observed using Sirius red staining; protein expression of Apelin was detected by immunohistochemistry; and the protein expression of matrix metalloproteinase (MMP)-2, 9 was detected by Western blotting.

RESULTS

During the experiment, the body mass of the sham operation group and SCG group was smaller than that of the blank control group (all P<0.05), and the body mass of the SCG group was larger than that of the sham operation group (all P<0.05). The heart rate and sympathetic activity of the sham operation group were higher than those of the blank control group (all P<0.05), while the SCG group were lower (all P<0.05). Compared with the blank control group, the aortic wall in the sham operation group was thickening, while that in the SCG group was improved. A large number of collagen-1 in the aortic wall of the blank control group was stained brown by Sirius red, which was lighter in SCG group, and the staining in the sham operation group was the lightest. Compared with the blank control group, the expression of Apelin, MMP-2 and MMP-9 protein in the sham operation group increased (all P<0.05), while those in the SCG group decreased (all P<0.05).

CONCLUSIONS

SCG can effectively reduce the incidence and mortality of aortic dissection in rats, which may be related to the inhibition of sympathetic activity and the decrease of collagen-1, Apelin, MMP-2 and MMP-9 expression.