Background: Continuous nerve block with ropivacaine is commonly performed after repair surgery for traumatic peripheral nerve injuries. After peripheral nerve injury, tetrodotoxin-resistant voltage-gated sodium channel Nav1.8 is upregulated and contributes to macrophage inflammation. This study investigated whether ropivacaine promotes peripheral nerve regeneration through Nav1.8-mediated macrophage signaling. Methods: A sciatic nerve transection-repair (SNT) model was established in adult Sprague–Dawley rats of both sexes. The rats received 0.2% ropivacaine or 10 μM Nav1.8-selective inhibitor A-803467 around the injured site or near the sacrum for 3 days. Nerve regeneration was evaluated using behavioral, electrophysiologic, and morphological examinations. Moreover, myelin debris removal, macrophage phenotype, Nav1.8 expression, and neuropeptide expression were assessed using immunostaining, enzyme-linked immunosorbent assay, and Western blotting. Results: Compared to the SNT-plus-vehicle group, the sensory, motor, and sensory–motor coordination functions of the two ropivacaine groups were significantly improved. Electrophysiologic (mean ± SD: recovery index of amplitude, vehicle 0.43 ± 0.17 vs. ropivacaine 0.83 ± 0.25, n = 11, P < 0.001) and histological analysis collectively indicated that ropivacaine significantly promoted axonal regrowth (percentage of neurofilament 200 [NF-200]–positive area: vehicle 19.88 ± 2.81 vs. ropivacaine 31.07 ± 2.62, n = 6, P < 0.001). The authors also found that, compared to the SNT-plus-vehicle group, the SNT-plus-ropivacaine group showed faster clearance of myelin debris, accompanied by significantly increased macrophage infiltration and transition from the M1 to M2 phenotype. Moreover, ropivacaine significantly attenuated Nav1.8 upregulation at 9 days after sciatic nerve transection (vehicle 4.12 ± 0.30-fold vs. ropivacaine 2.75 ± 0.36-fold, n = 5, P < 0.001), which coincided with the increased expression of chemokine ligand 2 and substance P. Similar changes were observed when using the selective Nav1.8 channel inhibitor A-803467. Conclusions: Continuous nerve block with ropivacaine promotes the structural and functional recovery of injured sciatic nerves, possibly by regulating Nav1.8-mediated macrophage signaling. Editor’s Perspective: What We Already Know about This Topic: What This Article Tells Us That Is New:

Background: Variable innervation of the clavicle is a major challenge in surgery of clavicle fractures with patients under regional anesthesia. An interscalene block (ISB) combined with an intermediate cervical plexus block (ICPB) provides analgesia in clavicle fracture surgery, but this combination does not completely block sensation in the midshaft or medial clavicle. Cervical nerve root block is an alternative to deep cervical plexus block and has recently been used as an analgesic method in the neck and shoulder. Whether it should be used as an alternative for midshaft and medial clavicle fractures is unknown. Questions/purposes: In this randomized controlled trial, we compared a C3, 4, and 5 nerve root block to ISB combined with ICPB in surgery of midshaft and medial clavicle fractures in terms of the (1) proportion of patients achieving a sensory block that is sufficient for surgery, (2) onset time and duration of the block, and (3) effectiveness of postoperative analgesia, as measured by pain scores and consumption of analgesics. Methods: Between November 2021 and December 2021, we treated 154 patients for clavicle fractures. A total of 122 were potentially eligible, 91 of whom agreed to participate in this study. Twenty-nine patients were excluded because the patients chose general anesthesia or declined to undergo surgery. Ultimately, 62 patients were randomly allocated into the C3, 4, and 5 group or ISB + ICPB group, with 31 patients in each group; there were no dropouts. All patients were analyzed in the group they were randomized to under intention-to-treat principles. The assessor and patients were blinded to randomization throughout the trial. The two groups did not differ in any important ways, including age, gender, BMI, American Society of Anesthesiologists classification, and type of clavicle fracture. The two groups received either an ultrasound-guided C3, 4, and 5 nerve root block with 2, 3, and 5 mL of 0.5% ropivacaine or ultrasound-guided ISB with ICPB with 20 mL of 0.5% ropivacaine. The primary outcome was the proportion of patients in each group with a successful nerveba block who did not receive general anesthesia; this was defined as nerve block success. Secondary outcomes included the onset time and duration of the sensory block, defined as the onset to the moment when the patients felt pain and sought rescue analgesia; pain assessment in terms of the numeric rating scale (NRS) score (range 0 to 10) for pain after nerve block before and during surgery; and the median amount of sufentanil consumed intraoperatively and postoperatively in the recovery room. The dosing of sufentanil was determined by the assessor when the NRS score was 1 to 3 points. If the NRS score was more than 3 points, general anesthesia was administered as a rescue method. Complications after the two inventions such as toxic reaction, dyspnea, hoarseness, pneumothorax, and Horner syndrome were also recorded in this study. Results: A higher proportion of patients in the C3, 4, and 5 group had a successful nerve block than in the ISB + ICPB group (97% [30 of 31] versus 68% [21 of 31], risk ratio 6 [95% CI 1.5 to 37]; p < 0.01). The median onset time was 2.5 minutes (range 2.0 to 3.0 minutes) in the C3, 4, and 5 group and 12 minutes (range 9 to 16 minutes) in the ISB + ICPB group (difference of medians 10 minutes; p < 0.001). The sensory block duration was 10 ± 2 hours in the C3, 4, and 5 group and 8 ± 2 hours in the ISB + ICPB group (mean difference 2 hours [95% CI 1 to 3 hours]; p < 0.001). The median sufentanil consumption was lower in the C3, 4, 5 group than in the ISB + ICPB (median 5 µg [range 0.0 to 5.0 µg] versus median 0 µg [range 0.0 to 0.0 µg]; difference of medians 5.0 µg; p < 0.001). There were no differences between the two groups regarding NRS scores after nerve blocks and NRS score for incision and periosteum separation, with the minimum clinically important difference set at a 2-point difference (of 10). There were no severe complications in this study. Conclusion: Based on our analysis of the data, a C3, 4, and 5 nerve root block was better than ISB combined with ICPB for surgery to treat medial shaft and medial clavicle fractures. When choosing the anesthesia method, however, the patient’s basic physiologic condition and possible complications should be considered. Level of Evidence: Level I, therapeutic study.

Background/Objectives: Pain-induced vasoconstriction and thrombosis cause vascular insufficiency, a major etiology of early necrosis in replanted digits. While systemic intravenous analgesia (SIVA) carries significant side effects, continuous brachial plexus block (CBPB) provides analgesia with vasodilation. Amidst uncertainties regarding distal vascular recanalization and sympathetic denervation, whether CBPB’s hemodynamic effects translate into improved perfusion and outcomes in replanted digits remains unknown. This randomized controlled trial compared the effects of CBPB versus SIVA on digit perfusion, vascular insufficiency, and survival rates post-replantation. Methods: After screening 113 patients, 55 patients (71 digits) were ultimately randomized and analyzed: the CBPB group (n = 27, 36 digits) received 0.2% ropivacaine infusion at 5 mL/h; the SIVA group (n = 28, 35 digits) received intravenous parecoxib 20 mg twice daily with supplemental tramadol for visual analog scale (VAS) scores > 3. The primary outcome was digital skin temperature trajectory measured at 0, 12, 24, 36, and 48 h postoperatively. Secondary outcomes included Doppler-quantified combined volumetric flow rate of the radial and ulnar arteries (RA-UA VFR) at identical timepoints, VAS scores, vascular insufficiency incidence, and 7-day digit survival. Results: CBPB significantly enhanced perfusion in replanted digits at all postoperative timepoints, with digital skin temperature peaking at 48 h (32 ± 1.6 °C vs. 31 ± 1.1 °C; p < 0.001) and RA-UA VFR peaking at 24 h (4.0 ± 0.83 vs. 1.8 ± 0.51 mL/s; p < 0.001) versus SIVA. Concurrently, CBPB provided superior analgesia (VAS 0.52 ± 0.51 vs. 1.9 ± 1.0; p < 0.001) and significantly reduced 48-h vascular insufficiency incidence (8.3% vs. 29%; p = 0.028). No significant difference was observed in seven-day survival rates between groups (97% vs. 91%; p = 0.329). Conclusions: CBPB significantly enhanced perfusion in replanted digits and reduced the incidence of vascular insufficiency, despite not conferring additional survival benefits.

The inferior vena cava collapsibility index (IVCCI) has been used to predict fluid responsiveness. This study aimed to evaluate the accuracy of the perioperative IVCCI to predict postinduction hypotension (PIH) under general anaesthesia (GA) combined with lumbar plexus sacral plexus block (LSPB) in elderly patients undergoing hip arthroplasty. A total of forty patients aged over 65 years were recruited for this prospective observational study. The diameters of the inferior vena cava (IVC), common iliac vein (CIV) and IVCCI were measured at baseline and 15 min post-LSPB. PIH was defined as a systolic blood pressure less than 90 mmHg or a ≥ 30% drop from baseline; patients were divided into hypotensive and nonhypotensive groups. The primary objective of this study was to evaluate the ability of the IVCCI to predict PIH via receiver operating characteristic (ROC) analysis. The secondary objective was to observe the change in CIV diameter. Eighteen patients (45%) developed PIH during GA. No statistically significant differences in baseline or post-LSPB IVCCI were detected between hypotensive and nonhypotensive patients (p > 0.05), whereas a significant expansion of the CIV (0.83 cm to 1.10 cm) was observed 15 min post-LSPB in all patients (p < 0.0001). According to the ROC curve analysis, the IVCCI cannot accurately predict severe PIH: the area under the ROC curve for the IVCCI was 0.54 (95% confidence interval: 0.35–0.72, P = 0.69). Thus, the IVCCI is not an effective predictor of PIH during GA combined with LSPB in elderly patients undergoing hip arthroplasty. Additionally, significant expansion of the CIV was observed 15 min after LSPB, indicating sympathetic blockade of the unilateral lower extremity.