Effects Of Sciatic Nerve Block Research Articles

Comparison of the effects of sciatic nerve block combined with continuted femoral nerve block or continuted adductor canal block on pain and motor function after total knee arthroplasty

To compare the effect of sciatic nerve block (SNB) combined with continuted femoral nerve block (FNB) or continuted adductor canal block (ACB) on pain and motor function after total knee arthroplasty (TKA). A total of 60 patients with TKA-treated osteoarthritis of the knee who met the selection criteria were enrolled between November 2020 and February 2021 and randomised allocated into the study group (SNB combined with continuted ACB) and the control group (SNB combined with continuted FNB), with 30 cases in each group. There was no significant difference in gender, age, body mass, height, body mass index, preoperative Hospital for Special Surgery (HSS) score, femoral tibial angle, and medial proximal tibial angle between the two groups ( P>0.05). The operation time, the initial time to the ground, the initial walking distance, and the postoperative hospital stay were recorded. At 2, 4, 6, 12, 24, and 48 hours after operation, the numerical rating scale (NRS) score was used to evaluate the rest pain around the knee joint, the quadriceps femoris muscle strength was evaluated by the freehand muscle strength method, and the knee flexion and extension angles were measured. There was no significant difference in the operation time and initial walking distance between the two groups ( P>0.05); the initial time to the ground and postoperative hospital stay of the study group were significantly shorter than those of the control group ( P<0.05). Except for the 48-hour postoperative NRS score of the study group, which was significantly lower than that of the control group ( P<0.05), there was no significant difference in the NRS scores between the two groups at the remaining time points ( P>0.05). The quadriceps femoris muscle strength from 4 to 24 hours postoperatively and the knee extension angle from 2 to 6 hours postoperatively of the study group were significantly better than those of the control group ( P<0.05); the differences in the quadriceps femoris muscle strength and knee extension and flexion angles between the two groups at the remaining time points were not significant ( P>0.05). SNB combined with either continuted ACB or continuted FNB can effectively relieve pain in patients after TKA, and compared with combined continuted FNB, combined continuted ACB has less effect on quadriceps femoris muscle strength, and patients have better recovery of knee flexion and extension mobility.

Sciatic nerve block downregulates the BDNF pathway to alleviate the neonatal incision-induced exaggeration of incisional pain via decreasing microglial activation

Sciatic nerve block is under investigation as a possible therapeutic strategy for neonatal injury-induced exaggeration of pain responses to reinjury. Spinal microglial priming, brain-derived neurotrophic factor (BDNF) and Src homology-2 domain-containing protein tyrosine phosphatase-2 (SHP2) participate in exaggerated incisional pain induced by neonatal incision. However, effects of sciatic nerve block on exacerbated incisional pain and underlying mechanisms remain unclear. Here, we demonstrated that sciatic nerve block alleviates pain hypersensitivity and microglial activation in rats subjected to neonatal incision and adult incision (nIN-IN). Chemogenetic activation or inhibition of spinal microglia attenuates or mimics effects of sciatic nerve block on pain hypersensitivity, respectively. Moreover, α-amino-3-hydroxy- 5-methy- 4-isoxazole propionate (AMPA) receptor subunit GluA1 contributes to the exaggeration of incisional pain. The inhibition of BDNF or SHP2 blocks upregulations of downstream molecules in nIN-IN rats. Knockdown of SHP2 attenuates the increase of GluA1 induced by injection of BDNF in adult rats with only neonatal incision. The inhibition of microglia or ablation of microglial BDNF attenuates upregulations of SHP2 and GluA1. Additionally, sciatic nerve block downregulates the expression of these three molecules. Upregulation of BDNF, SHP2 or AMPA receptor attenuates sciatic nerve block-induced reductions of downstream molecules and pain hypersensitivity. Microglial activation abrogates reductions of these three molecules induced by sciatic nerve block. These results suggest that decreased activation of spinal microglia contributes to beneficial effects of sciatic nerve block on the neonatal incision-induced exaggeration of incisional pain via downregulating BDNF/SHP2/GluA1-containing AMPA receptor signaling. Thus, sciatic nerve block may be a promising therapy.

Neuronal Nitric Oxide Synthase Suppression Confers the Prolonged Analgesic Effect of Sciatic Nerve Block With Perineural Dexamethasone in Postoperative Pain Model Mice

Dexamethasone supplementation to local anesthetics prolongs its action, yet the underlying mechanism is unclear. Previous studies have reported that increased p-p38 mitogen-activated protein kinase (MAPK) in the dorsal root ganglia (DRG) is associated with pain-associated behavior and that nitric oxide (NO), which is known to be a pronociceptive substance, directly inhibits sciatic nerve conduction. Here, we investigated the temporal changes in the hyperalgesic effect and p-p38 MAPK and NO synthase (NOS) expression levels in the DRG when dexamethasone was added to ropivacaine used for a sciatic nerve block (SNB) in postoperative pain model mice. Dexamethasone supplementation to ropivacaine significantly prolonged the analgesic effect of SNB via glucocorticoid receptor activation. Histological examination revealed that ropivacaine suppressed p-p38 MAPK expression in the DRG regardless of dexamethasone supplementation, suggesting that p-p38 MAPK was not involved in the prolonging effect of dexamethasone on nerve block. Contrastingly, plantar incision markedly increased the expression of neuronal NOS (nNOS) in DRG, and dexamethasone supplementation to ropivacaine significantly suppressed nNOS expression. Supplementation of L-NAME, an inhibitor of NOS, to ropivacaine markedly prolonged the effect of SNB, similar to dexamethasone. These results suggest that dexamethasone supplementation to local anesthetics prolongs the analgesic effect by inhibiting nNOS activity. PerspectiveThe current study revealed that dexamethasone supplementation to local anesthetics prolongs the analgesic effect by inhibiting the activity of neuronal NOS and that p-p38 MAPK may not be involved in this phenomenon. Our findings offer a new target for the discovery of long-acting local anesthetics.

Dexmedetomidine as an Adjuvant in Sciatic Nerve Block for Lower Limb Surgeries: An Observational Study

Background: In recent anesthetic practice, peripheral nerve blocks (PNB) are used extensively for surgical anesthesia and non-surgical postop analgesia. PNBs offer many benefits over other anesthetic techniques in a certain population of patients and in some specific clinical setting that may contribute to faster and safer pain relief, increased patient satisfaction, reduced hospital stay, and decreased overall healthcare cost. However, the use of a single PNB is not sufficient enough to block the pain for longer durations. Hence, to prolong the effect of anesthesia without causing any adverse event, adjuvants are injected perineurally along with local anesthetic agents. Aim: The present study was aimed to evaluate the anesthetic efficacy of dexmedetomidine as an adjuvant in sciatic nerve block in lower limb surgery patients.Subjects and Methods:This observational non-randomized study involved 50 patients who were undergoing lower limb surgeries in the study period. The heart rate, blood pressure (both SBP and DBP), and peripheral oxygen saturation were recorded. A VAS score of more than 5 was considered significant and these patients received tramadol injection (75 mg) i.v. As rescue analgesia in the postop period. To prolong the effect of sciatic nerve block, dexmedetomidine (0.5 mcg/kg) was used.Results:In the maximum number of the patient,the complete block was achieved. Only 6 patients required tramadol injection as the rescue analgesia. No significant post and intraoperative complications were reported after the procedure.Conclusion:It is concluded from the study that the inclusion of dexmedetomidine (0.5 mcg/kg) in lower limb surgeries was associated with a prolonged duration of analgesia.

Physical disuse contributes to widespread chronic mechanical hyperalgesia, tactile allodynia, and cold allodynia through neurogenic inflammation and spino-parabrachio-amygdaloid pathway activation.

Physical disuse could lead to a state of chronic pain typified by complex regional pain syndrome type I due to fear of pain through movement (kinesiophobia) or inappropriate resting procedures. However, the mechanisms by which physical disuse is associated with acute/chronic pain and other pathological signs remain unresolved. We have previously reported that inflammatory signs, contractures, disuse muscle atrophy, spontaneous pain-like behaviors, and chronic widespread mechanical hyperalgesia based on central plasticity occurred after 2 weeks of cast immobilization in chronic post-cast pain (CPCP) rat model. In this study, we also demonstrated dystrophy-like changes, both peripheral nociceptive signals and activation of the central pain pathway in CPCP rats. This was done by the following methods: (1) vascular permeability (Evans blue dye) and inflammatory- and oxidative stress-related messenger RNA changes (real-time quantitative polymerase chain reaction); (2) immunofluorescence of pERK and/or c-Fos expression in the spino-parabrachio-amygdaloid pathway; and (3) blockade of nociceptive-related signals using sciatic nerve block. Furthermore, we demonstrated tactile allodynia using an optogenetic method in a transgenic rat line (W-TChR2V4), cold allodynia using the acetone test, and activation of dorsal horn neurons in the chronic phase associated with chronic mechanical hyperalgesia using c-Fos immunofluorescence. In addition, we showed that nociceptive signals in the acute phase are involved in chronic pathological pain-like behaviors by studying the effects of sciatic nerve block. Thus, we conclude that physical disuse contributes to dystrophy-like changes, spontaneous pain-like behavior, and chronic widespread pathological pain-like behaviors in CPCP rats after 2 weeks of cast immobilization.

Efek Regional dan Cardiopulmonary Penggunaan Lidocaine dan Lidocaine-Xylazine pada Blokade Nervus Ischiadicus Domba (REGIONAL AND CARDIOPULMONARY EFFECTS OF LIDOCAINE AND LIDOCAINEXYLAZINE IN SHEEP SCIATIC NERVE BLOCK)

General anaesthesia has a high risk during surgery, regional anaesthesia with nerve block is expected to minimize the use of general anaesthesia while increase the analgesic effect and muscle relaxation effect. This study aimed to compare the analgesic effects of sciatic nerve block on the hind limb and the effect of lidocaine 2%, and a combination of 2% lidocaine with 2% xylazine on sheep cardiopulmonary function. Sciatic nerve block was guided with ultrasonography and nerve stimulator. In this research, sheep were sedated with diazepam (0.5 mg / kg). Sheep was divided into three groups; first injected with saline solution (SS), second with lidocaine 2% 5 mg / kg (Lid) and third with lidocaine 2% 5 mg / kg and xylazine 2% 0.1 mg / kg (LidXyl). The results of this research showed that the LidXyl group had the highest analgesic effect and broader blockade area, namely femoris, cruris, and metatarsus-digit. The LidXyl blockade value was highest in the digitmetatarsus region, while the Lid group shows the highest blockade value in the cruris region. The LidXyl group with the addition of xylazine results in a decrease in heart rate and respiration rate. Xylazine increased and extended analgesic effect compared to lidocaine but resulted in a decrease in heart rate and respiration rate in the early minutes of anaesthesia, it is however safe to be used in sheep.

Addition of dexmedetomidine to QX-314 enhances the onset and duration of sciatic nerve block in rats.

An experimental set-up was designed to observe whether adding dexmedetomidine to QX-314 would enhance the onset and duration of sensory and motor function in a rat sciatic nerve block model. Fifty-six Sprague-Dawley rats received unilateral sciatic nerve blocks with 0.2 mL of 35 mmol/L QX-314 alone, dexmedetomidine (5.3 μmol/L (1 μg/kg), 26.4 μmol/L (5 μg/kg), 52.8 μmol/L (10 μg/kg)) alone, or a combination of the two. Thermal nociception and motor function were assessed by an investigator blinded to the drug treatment, and sciatic nerves and perineural tissues were harvested at 14 days after injection. In addition, we examined the effects of these solutions on compound action potentials in isolated frog sciatic nerves. Dexmedetomidine added to QX-314 enhanced the onset and duration of thermal nociception block and motor block (P < 0.05) without aggravating histopathological injuries. Furthermore, 52.8 μmol/L dexmedetomidine added to 35 mmol/L QX-314 showed less inflammation than QX-314 alone at 14 days (P = 0.003). Dexmedetomidine plus QX-314 was shown to dose-dependently reduce the compound action potentials relative to QX-314 alone (P < 0.05). It was concluded that co-administration of QX-314 with a clinical dose of dexmedetomidine produced a synergistic anesthetic effect to enhance the effect of sciatic nerve block.

Long-term effect of ropivacaine nanoparticles for sciatic nerve block on postoperative pain in rats

PurposeThe analgesic effect of ropivacaine (Rop) for nerve block lasts only ~3–6 hours for single use. The aim of this study was to develop long-acting regional anesthetic Rop nanoparticles and investigate the effects of sciatic nerve block on postoperative pain in rats.Materials and methodsRop nanoparticles were developed using polyethylene glycol-co-polylactic acid (PELA). One hundred and twenty adult male Wistar rats were randomly divided into four groups (n=30, each): Con (control group; 0.9% saline, 200 µL), PELA (PELA group; 10 mg), Rop (Rop group; 0.5%, 200 µL), and Rop-PELA (Rop-PELA group; 10%, 10 mg). Another 12 rats were used for the detection of Rop concentration in plasma. The mechanical withdrawal threshold and thermal withdrawal latency were measured at 2 hours, 4 hours, 8 hours, 1 day, 2 days, 3 days, 5 days, and 7 days after incision. The expression of c-FOS was determined by immunohistochemistry at 2 hours, 8 hours, 48 hours, and 7 days. Nerve and organ toxicities were also evaluated at 7 days.ResultsThe duration of Rop absorption in the plasma of the Rop-PELA group was longer (>8 hours) than that of the Rop group (4 hours). Mechanical withdrawal threshold and thermal withdrawal latency in the Rop-PELA group were higher than that in other groups (4 hours–3 days). c-FOS expression in the Rop-PELA group was lower than that in the control group at 2 hours, 8 hours, and 48 hours and lower than that in the Rop group at 8 hours and 48 hours after paw incision. Slight foreign body reactions were observed surrounding the sciatic nerve at 7 days. No obvious pathophysiological change was found in the major organs after Rop-PELA administration at 7 days.ConclusionRop-PELA provides an effective analgesia for nerve block over 3 days after single administration, and the analgesic mechanism might be mediated by the regulation of spinal c-FOS expression. However, its potential long-term tissue toxicity needs to be further investigated.

Effects of sciatic nerve block on emergence agitation following sevoflurane-based anesthesia in pediatric patients undergoing foot orthomorphia

Objective To evaluate the effects of the sciatic nerve block on emergence agitation following sevoflurane-based anesthesia in pediatric patients undergoing foot orthomorphia.Methods Sixty pediatric patients,aged 3-7 yr,weighing 12-20 kg,of ASA physical status Ⅰ or Ⅱ,scheduled for elective foot orthomorphia,were randomly assigned to one of two groups (n =30 each):control group (group Ⅰ) and sciatic nerve block group (group Ⅱ).After induction of anesthesia,laryngeal mask airway was inserted,and artificial or mechanical ventilation was performed.Anesthesia was maintained with inhalation of sevoflurane (end-tidal concentration 0.5％-2.0％) and iv fentanyl 0.5-2.0 μg/kg.The sciatic nerve block on the affected side was performed under the guidance of a nerve stimulator,and 0.25％ bupivacaine 0.5 ml/kg was injected.Laryngeal mask airway removal time and emergence time were recorded.At 30 min of recovery from anesthesia,agitation was scored and the development of emergence agitation was recorded.Pain was evaluated with Faces Pain Scale-Revised (FPS-R) at 10 and 30 min of recovery from anesthesia.Adverse reactions including hypoxemia and nausea and vomiting were also recorded during recovery from anesthesia.Results Compared with group Ⅰ,the intraoperative consumption of fen tanyl and mean end-tidal concentration of sevoflurane were significantly decreased,laryngeal mask airway removal time and emergence time were shortened,and the incidence of emergence agitation,PPS-P scores and incidence of hypoxemia were decreased in group Ⅱ.Conclusion The sciatic nerve block is helpful in decreasing the development of emergence agitation following sevoflurane-based anesthesia in pediatric patients undergoing foot orthomorphia. Key words: Nerve block ; Sciatic nerve ; Anesthetics, inhalation ; Anesthesia recovery period; Children; Agitation

Long-term Effect of Sciatic Nerve Block with Slow-release Lidocaine in a Rat Model of Postoperative Pain

Postoperative pain management is important for preventing perioperative complications. The authors examined the effectiveness of controlled-release lidocaine for sciatic nerve block in a rat model of postoperative pain. The authors created a novel slow-release lidocaine sheet (SRLS) with polylactic-coglycolic acid. In male Sprague-Dawley rats (postoperative pain model), the authors applied the SRLS, lidocaine alone, or polylactic-coglycolic acid (control) near the ipsilateral sciatic nerve just before making the paw incision. Mechanical hypersensitivity was assessed using von Frey filaments, and c-fos expression was examined in the spinal cord dorsal horn at segments L4-L5. Neurotoxicity and muscle toxicity were also evaluated via histopathology. The SRLS (30%, w/w) continuously released lidocaine for 1 week in vitro. The withdrawal threshold in the SRLS-treated group was higher than that in the control group at all time points measured (2 h to 7 days). The withdrawal threshold in the lidocaine-treated group was higher than that in the control group only at 2 h after paw incision. The mean number of c-fos immunoreactive neurons in the SRLS-treated group was lower than in the control group at 2, 5, and 48 h after paw incision and lower than in the lidocaine-treated group at 5 and 48 h after paw incision. On histopathology, signs of inflammation were only slightly present in the muscle and nerve tissues of the SRLS-treated group. Single treatment with the SRLS inhibited hyperalgesia and c-fos expression in the spinal cord dorsal horn for 1 week. Slow-release local anesthetics are promising for the management of postoperative pain.

The antinociceptive and histologic effect of sciatic nerve blocks with 5% butamben suspension in rats.

Butamben, a lipophilic local anesthetic of the ester class, produces a differential nerve block of long duration. Epidural and peripheral nerve blocks with butamben, formulated as a 5%--10% suspension, result in prolonged analgesia without significant motor blockade. We evaluated the effect of butamben sciatic nerve block on antinociception using the rat paw formalin test, as well as withdrawal latencies to thermal stimulation, and assessed histologic changes in the nerve. After right sciatic nerve block with butamben 5% or saline, responses to intradermal injection of 5% formalin were recorded in randomly selected groups of 6 animals each on days 1, 2, 5, 10, 21, and 28. In an additional group of 8 thermal challenges to both hind paws were recorded at 1, 2, 5, 7, 10, 14, 17, 21, and 28 days after right sciatic butamben 5% blocks. Butamben injection decreased the formalin-induced flinches on days 2, 5, 10, 21 and 28 and decreased thermal challenges on days 1 through 17. Histologic changes were minimal. This study demonstrates a prolonged antinociceptive effect from butamben nerve block to both formalin-induced nociception and heat hyperalgesia, without an effect on gross motor function or histologic morphology. Butamben 5% nerve blocks produced a prolonged antinociceptive effect to formalin-induced nociception and heat hyperalgesia, without significant motor effect or evidence of substantial histologic changes.