Serratus Anterior Plane Block: A Better Modality of Pain Control after Pectus Excavatum Repair.

Background: Postoperative pain management following minimally invasive repair of pectus excavatum (MIRPE) remains a critical concern due to severe post-procedural pain. Promising results have been reported for cryoanalgesia following MIRPE; however, its invasiveness, single-lung ventilation, and additional instrumentation requirements remain obstacles. Serratus anterior plane block (SAPB) is a regional block technique capable of covering the anterior chest wall at the T2-9 levels, which are affected by MIRPE. We hypothesized that SAPB would be a superior alternative pain control modality that reduces postoperative pain more effectively than conventional methods. Methods: We conducted a retrospective study of patients who underwent MIRPE between March 2022 and August 2023. The efficacy of pain control was compared between group N (conventional pain management, n=24) and group S (SAPB, n=26). Group N received intravenous patient-controlled analgesia (IV-PCA) and subcutaneous local anesthetic infusion. Group S received bilateral continuous SAPB with 0.3% ropivacaine after a bilateral bolus injection of 30 mL of 0.25% ropivacaine with baseline IV-PCA. Pain levels were evaluated using a Visual Analog Scale (VAS) at 1, 3, 6, 12, 24, 48, and 72 hours postoperatively and total intravenous rescue analgesic consumption by morphine milligram equivalents (MME). Results: Mean VAS scores were significantly lower in group S than in group N throughout the 72-hour postoperative period (p<0.01). Group S showed significantly lower MME at postoperative 72 hours (group N: 108.53, group S: 16.61; p<0.01). Conclusion: SAPB improved immediate postoperative pain control in both the resting and dynamic states and reduced opioid consumption compared to conventional management.

Serratus anterior plane block for acute pain management after pectus excavatum repair.

Introduction: Conventional postoperative pain management using an intravenous (IV) patient-controlled approach or thoracic epidural analgesia is suboptimal following minimally invasive repair of the pectus excavatum (MIRPE). Recently, cryoanalgesia has gained popularity owing to its superior pain control outcomes compared to those associated with conventional methods. However, because of its invasiveness, additional instrumentation requirement, and limited effect at early postoperative periods, we hypothesized that serratus anterior plane block (SAPB) could be an effective method for post-repair pain management and a possibly superior alternative. Methods: We conducted a retrospective cohort study of pediatric patients who had undergone MIRPE between March 2022 and August 2023. We compared the efficacy of pain control in three groups among 74 patients: Group N (conventional pain management, n = 24), Group C (cryoanalgesia, n = 24), and Group S (SAPB, n = 26). Group N received IV patient-controlled analgesia (PCA) and a subcutaneous local anesthetic infusion. Group C received bilateral cryoanalgesia on the fourth and seventh intercostal nerves using a cryoprobe at -80°C for 2 min during the operation and IV-PCA postoperatively. Group S received continuous bilateral SAPB with 0.25% ropivacaine and IV-PCA. The pain levels were measured using the visual analog scale (VAS; resting and dynamic), and the total IV rescue analgesic consumption was determined. Results: The three groups had similar baseline characteristics. Group S showed significantly less pain throughout the immediate postoperative course, resting VAS score at 3 h (Group N, 7.21 vs. Group C, 5.75 vs. Group S, 3.81; p < 0.001), and prominent less total IV rescue analgesic consumption (Group N, 116.16 mg vs. Group C, 52.75 mg vs. Group S, 16.61 mg; p < 0.001). Conclusion: SAPB resulted in better postoperative pain control than that associated with cryoanalgesia and conventional pain management after pectus excavatum repair, As it was effective in the immediate postoperative period, achieving a VAS score of <4 points (moderate pain) at 3 h postoperatively, it may play an important role and replace invasive cryoanalgesia in the management of pain after pectus surgery.

Regulation of GLUT4 gene expression by SREBP-1c in adipocytes.

Expression of the GLUT4 (glucose transporter type 4 isoform) gene in adipocytes is subject to hormonal or metabolic control. In the present study, we have characterized an adipose tissue transcription factor that is influenced by fasting/refeeding regimens and insulin. Northern blotting showed that refeeding increased GLUT4 mRNA levels for 24 h in adipose tissue. Consistent with an increased GLUT4 gene expression, the mRNA levels of SREBP (sterol-regulatory-element-binding protein)-1c in adipose tissue were also increased by refeeding. In streptozotocin-induced diabetic rats, insulin treatment increased the mRNA levels of GLUT4 in adipose tissue. Serial deletion, luciferase reporter assays and electrophoretic mobility-shift assay studies indicated that the putative sterol response element is located in the region between bases -109 and -100 of the human GLUT4 promoter. Transduction of the SREBP-1c dominant negative form to differentiated 3T3-L1 adipocytes caused a reduction in the mRNA levels of GLUT4, suggesting that SREBP-1c mediates the transcription of GLUT4. In vivo chromatin immunoprecipitation revealed that refeeding increased the binding of SREBP-1 to the putative sterol-response element in the GLUT4. Furthermore, treating streptozotocin-induced diabetic rats with insulin restored SREBP-1 binding. In addition, we have identified an Sp1 binding site adjacent to the functional sterol-response element in the GLUT4 promoter. The Sp1 site appears to play an additive role in SREBP-1c mediated GLUT4 gene upregulation. These results suggest that upregulation of GLUT4 gene transcription might be directly mediated by SREBP-1c in adipose tissue.

Glucose-stimulated upregulation of GLUT2 gene is mediated by sterol response element-binding protein-1c in the hepatocytes.

GLUT2 is mainly expressed in the liver, beta-cells of the pancreas, and the basolateral membrane of kidney proximal tubules and plays an important role in glucose homeostasis in living organisms. The transcription of the GLUT2 gene is known to be upregulated in the liver during postprandial hyperglycemic states or in type 2 diabetes. However, a molecular mechanism by which glucose activates GLUT2 gene expression is not known. In this study, we report evidence that sterol response element-binding protein (SREBP)-1c plays a key role in glucose-stimulated GLUT2 gene expression. The GLUT2 promoter reporter is activated by SREBP-1c, and the activation is inhibited by a dominant-negative form of SREBP-1c (SREBP-1c DN). Adenoviral expression of SREBP-1c DN suppressed glucose-stimulated GLUT2 mRNA level in primary hepatocytes. An electrophoretic mobility shift assay and mutational analysis of the GLUT2 promoter revealed that SREBP-1c binds to the -84/-76 region of the GLUT2 promoter. Chromatin immunoprecipitation revealed that the binding of SREBP-1c to the -84/-76 region was increased by glucose concentration in a dose-dependent manner. These results indicate that SREBP-1c mediates glucose-stimulated GLUT2 gene expression in hepatocytes.