Clinical application of ropivacaine for the lower extremity

Ropivacaine Promotes Axon Regeneration by Regulating Nav1.8-mediated Macrophage Signaling after Sciatic Nerve Injury in Rats

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

Spinal anesthesia for L5-S1 interlaminar endoscopic lumbar discectomy: a retrospective study

OBJECTIVE

This study aimed to report our experience with spinal anesthesia (SA) in patients undergoing L5-S1 interlaminar endoscopic lumbar discectomy (IELD) and clarify its advantages and disadvantages.

METHODS

One hundred twelve patients who underwent IELD for an L5-S1 disc herniation under SA were retrospectively analyzed. SA with 0.5% ropivacaine was administered using a 27-gauge fine needle. Intraoperatively, the volume and level of SA, surgical time, blood loss, and cardiopulmonary complications were documented. Postoperative data was collected included the number of patients who ambulated on the day of surgery, incidence of complications and were then statistically analyzed.

RESULTS

Analgesia was complete throughout the entire operation in all patients and no other adjuvant intraoperative analgesic drugs were needed. Mean visual analog scale scores for intraoperative and early postoperative (24 h) pain were 0 and 2.43 ± 1.66. SA was administered at the L3-4 interspace in 34 patients (30.4%) and the L2-3 interspace in 78 (69.6%). Administration was successful with the first attempt in all patients. Mean operation time was 70.12 ± 6.52 min. Mean intraoperative blood loss volume was 20.71 ± 5.26 ml. Ninety-eight patients ambulated on the same day as surgery. Mean length of hospital stay was 24.36 ± 3.64 h. Dural injury without damaging the nerve root occurred in one patient. One patient experienced recurrent disc herniation. Intraoperative hypotension and respiratory distress occurred in five (4.5%) and three (2.7%) patients, respectively. Three patients (2.7%) received postoperative analgesia therapy and two (1.8%) experienced nausea. Two patients (1.8%) developed urinary retention. Spinal headache, cauda equina syndrome, and neurotoxicity did not occur.

CONCLUSION

SA can achieve satisfactory pain control for patients undergoing IELD with a low incidence of adverse events. SA may be a useful alternative to local and general anesthesia for IELD surgery. Future randomized controlled trials are warranted to investigate.

The Median Effective Analgesic Concentration of Ropivacaine in Sciatic Nerve Block Guided by Ultrasound After Arthroscopic Anterior Cruciate Ligament Reconstruction: A Double-Blind Up-Down Concentration-Finding Study

Background

The median effective analgesic concentration (MEAC; EC50 = effective concentration in 50% patients) of ropivacaine in sciatic nerve block guided by ultrasound (US) required for effective postoperative analgesia following arthroscopic anterior cruciate ligament (ACL) reconstruction has not yet been found. This study aimed to determine the effectiveness of MEAC of 20 ml ropivacaine of postoperative anesthesia for patients after ACL reconstruction.

Methods

In total, 29 patients who underwent elective arthroscopic ACL reconstruction were enrolled in this study. All the subjects were given 20 ml of 0.2% ropivacaine for femoral nerve block. A concentration of 20 ml ropivacaine administered to the sciatic nerve was measured by applying the up-and-down sequential method (UDM). The starting concentration was 0.2% in the first patient, and the next patient received decremented 0.025% ropivacaine if the prior patient's postoperative visual analog pain score was <4 in the initial 8 h. Otherwise, the participant was given an incremental dose of 0.025% ropivacaine. The EC50 of ropivacaine was determined by using centered isotonic, linear-logarithmic, exponential regressions, and linear regression. The “goodness of fit” was compared among various models by calculating the residual standard errors.

Results

The concentration of ropivacaine administered ranged from 0.1 to 0.2%. The EC50 [95% confidence interval (CI)] determined by four statistical methods (centered isotonic, exponential regressions, linear-logarithmic, and linear regression) was 0.115, 0.113% (0.108, 0.343%), 0.142% (0.112, 0.347%), and 0.129% (0.103, 0.359%), respectively. Among all models, the residual standard error was the smallest for the exponential regression (0.2243).

Conclusion

The EC50 of ropivacaine in US-guided sciatic nerve block was 0.113–0.142%, and exponential regression model best matched the data.

No Difference between Spinal Anesthesia with Hyperbaric Ropivacaine and Intravenous Dexmedetomidine Sedation with and without Intrathecal Fentanyl: A Randomized Noninferiority Trial

To enhance the duration of single-shot spinal anesthesia, intrathecal fentanyl and intravenous dexmedetomidine are widely used as adjuvants to local anesthetics. This noninferiority trial evaluated whether hyperbaric ropivacaine alone can produce a noninferior duration of sensory block in comparison to hyperbaric ropivacaine with intrathecal fentanyl in patients under dexmedetomidine sedation. Methods. Fifty patients scheduled for elective lower limb surgery under spinal anesthesia were randomly assigned in a double-blind fashion to receive either hyperbaric ropivacaine 15 mg (Group R) or hyperbaric ropivacaine 15 mg with intrathecal fentanyl 20 μg (Group RF). Intravenous dexmedetomidine (1 μg/kg for 10 min, followed by 0.5 μg/kg/h) was administered in both groups. The primary outcome of this study was the time to two-dermatomal regression of sensory block. The noninferiority margin for the mean difference was −10 min. Characteristics of the block, intraoperative and postoperative side effects, postoperative pain score, and analgesic consumption were assessed as secondary outcomes. Results. There was no difference in the two-dermatomal regressions of sensory block between the two groups (Group R 70.4 ± 10.2 min, Group RF 71.2 ± 12.4 min, $p$  = 0.804) with a mean difference of 0.8 min (−7.2 to 5.6, 95% confidence interval). Thus, the noninferiority of hyperbaric ropivacaine alone was established. There were no significant differences in the secondary outcomes between the two groups. Conclusions. Under intravenous dexmedetomidine sedation, the duration of spinal anesthesia with hyperbaric ropivacaine alone was noninferior to that of hyperbaric ropivacaine with intrathecal fentanyl. This suggests that addition of intrathecal fentanyl to hyperbaric ropivacaine may not be necessary in patients receiving intravenous dexmedetomidine.

Intrathecal fentanyl as an adjuvant to 0.75% isobaric ropivacaine for infraumbilical surgery under subarachnoid block: A prospective study

Background:

Subarachnoid blockade can be used in all surgical procedures carried out on the infraumbilical region. This study was aimed to evaluate the clinical efficacy and safety of intrathecal fentanyl as an adjuvant to 0.75% isobaric ropivacaine on onset, duration, intensity, and recovery time of sensory and motor blockade of subarachnoid block for infra umbilical surgery.

Methods:

One hundred sixty adult consented patients of either gender with American Society of Anesthesiologist ASA I and II scheduled for infraumbilical surgery were randomized into two groups of 80 patients each to receive either intrathecal study solution of 4 mL of 0.75% ropivacaine with 0.4 mL of 0.9% sodium chloride (Group I-Ropivacaine Control Group RC) or fentanyl (20 μg) (Group II-Ropivacaine with Fentanyl RF). The end points were hemodynamic variability, onset of analgesia at T 10, maximum sensory analgesic level, time to complete motor blockade, duration of sensory and motor blockade and adequacy of surgical anesthesia. The post-spinal nausea and vomiting, shivering, pruritus, respiratory depression or any other side-effects were also assessed. At the end of study, data were systematically complied and analyzed for statistically significance.

Result:

The intrathecal fentanyl has accelerated the onset time to achieve sensory blockade to T10 dermatome and motor blockade. Small dose of intrathecal fentanyl with ropivacaine has prolonged the duration of analgesia in the early post-operative period when compared with intrathecal ropivacaine alone. The intraoperative hemodynamic variability showed no statistically significant differences between groups.

Conclusion:

Intrathecal fentanyl as an adjuvant to 0.75% isobaric ropivacaine demonstrated better clinical profile as compared to ropivacaine alone.

Hemiarthroplasty in high risk elderly patient under epidural anesthesia with 0.75% ropivacaine-fentanyl versus 0.5% bupivacaine-fentanyl: Clinical trial

Background:

Anesthetic management of elderly patients is a challenge as aging makes them more susceptible to hemodynamic fluctuations during regional anesthesia. This study was aimed to compare the clinical efficacy of epidural 0.75% ropivacaine fentanyl (RF)– with 0.5% bupivacaine–fentanyl (BF) for hemiarthroplasty in high-risk elderly patients.

Methods:

Sixty elderly consented patients of either sex with American Society of Anesthesiologist ASA II and III, scheduled for elective hemiarthroplasty were randomized into two Groups of 30 patients to receive epidural study solution of 15 mL of 0.75% Ropivacaine or 0.5% Bupivacaine with 1 mL fentanyl (50 μg). The hemodynamic variability with onset and duration of sensory and motor blocks were recorded. The adequacy and quality of surgical anesthesia were assessed. The post-epidural nausea and vomiting, shivering, respiratory parameters, or any other side effects were also recorded.

Results:

There was no difference in the demographic profile between groups. The mean onset time to achieve sensory block to the T₁₀ dermatome was rapid in the Group BF (12.4±6.9 vs. 17.5±3.7 min in Group RF). The mean time to achieve motor block was 17.5±3.4 min in Group BF versus 21.7±7.8 min in Group RF. The intraoperative hemodynamic fluctuations showed statistically significant differences between groups. The pruritis was observed in five patients but post-epidural shivering, nausea, vomiting, respiratory depression, or urinary retention were not observed in any patient.

Conclusion:

Epidural 0.75% Ropivacaine with fentanyl showed better clinical profile as compared to 0.5% Bupivacaine with fentanyl for hemiarthroplasty in elderly patients.

Antinociceptive effects of low dose lumbosacral epidural ropivacaine in healthy ponies

The objective of this study was to evaluate the safety and efficacy of low dose lumbosacral epidural ropivacaine in ponies. Antinociceptive effects of epidural ropivacaine were evaluated by means of mechanical nociceptive thresholds (MNTs) at several spinal levels in conscious ponies. The effects of ropivacaine on nociceptive afferent transmission to the spinal cord were also assessed by measuring spinal cord somatosensory evoked potentials (SSEPs) in anaesthetised ponies. Ataxia scores were determined in conscious ponies to assess the effects on motor function. A randomised, placebo controlled, double blind cross-over design was used. Low dose lumbosacral epidural ropivacaine led to increases in MNTs at various anatomical locations with a maximum effect at the lumbosacral and sacrococcygeal regions, both with respect to increase in threshold and duration of effect. Analysis of SSEPs showed that epidural ropivacaine influenced both Aβ- and Aδ-mediated afferent transmission to the spinal cord at the level of the lumbosacral junction. Ponies showed mild ataxia after low dose lumbosacral epidural ropivacaine, but all ponies remained standing. Application of low dose lumbosacral epidural ropivacaine provided safe and efficacious antinociceptive effects in conscious and anaesthetised ponies, and could therefore be a valuable addition to multimodal analgesic protocols in Equidae.