Effects and mechanisms of perioperative medications on the hypothalamic pituitary adrenal response to surgical injury: A narrative review

The adrenal gland is a vital endocrine organ, and adrenal steroid synthesis and secretion are closely regulated by the hypothalamic-pituitary-adrenal (HPA) axis in response to various stimuli. Surgery or trauma can activate the HPA axis and induce the secretion of cortisol. Different cortisol responses vary with the grade of surgery. Perioperative medications have the potential to decrease the cortisol level in the body, and both excessive and insufficient cortisol levels after surgery are disadvantageous. The effect of perioperative medications on the HPA response to surgery can be divided into three levels: "adrenal insufficiency (AI)", "stress response inhibition", and "uncertainty". The clinical presentation of AI includes fatigue, nausea, vomiting, abdominal pain, muscle cramps, hypotension, hypovolemic shock and prerenal failure, which may result in fatal consequences. Stress response inhibition can reduce postoperative complications, such as pain and cognitive dysfunction. This is protective to patients during perioperative and postoperative periods. The aim of the present review is to shed light on current evidence regarding the exact effects and mechanisms of perioperative medications on the HPA response to surgical injury and provide the applicable guidance on clinical anesthesia.

Local Anesthetics, Local Anesthetic Systemic Toxicity (LAST), and Liposomal Bupivacaine

Local anesthetics have played a vital role in the multimodal analgesia approach to patient care by decreasing the use of perioperative opioids, enhancing patient satisfaction, decreasing the incidence of postoperative nausea and vomiting, decreasing the length of hospital stay, and reducing the risk of chronic postsurgical pain. The opioid-reduced anesthetic management for perioperative analgesia has been largely successful with the use of local anesthetics during procedures such as peripheral nerve blocks and neuraxial analgesia. It is important that practitioners who use local anesthetics are aware of the risk factors, presentation, and management of local anesthetic systemic toxicity (LAST).

Role of mitochondrial DNA level in epidural-related maternal fever: a single-centre, observational, pilot study

INTRODUCTION

Epidural analgesia has been associated with intrapartum maternal fever development. Epidural-related maternal fever (ERMF) is believed to be based on a non-infectious inflammatory reaction. Circulating cell-free mitochondrial deoxyribonucleic acid (mtDNA) is one of the possible triggers of sterile inflammatory processes; however, a connection has not been investigated so far. Therefore, this study aimed to investigate cell-free mtDNA alterations in women in labour with ERMF in comparison with non-febrile women.

MATERIAL AND METHODS

A total of 60 women in labour were assessed for maternal temperature every 4 h and blood samples were obtained at the beginning and after delivery. Depending on the analgesia and the development of fever (axillary temperature ≥ 37.5 °C), the women were allocated either to the group of no epidural analgesia (n = 17), to epidural analgesia no fever (n = 34) or to ERMF (n = 9). Circulating cell-free mtDNA was analysed in the maternal plasma for the primary outcome whereas secondary outcomes include the evaluation of inflammatory cytokine release, as well as placental inflammatory signs.

RESULTS

Of the women with epidural analgesia, 20% (n = 9) developed ERMF and demonstrated a decrease of circulating mtDNA levels during labour (p = 0.04), but a trend towards higher free nuclear DNA. Furthermore, women with maternal pyrexia showed a 1.5 fold increased level of Interleukin-6 during labour. A correlation was found between premature rupture of membranes and ERMF.

CONCLUSIONS

The pilot trial revealed an evident obstetric anaesthesia phenomenon of maternal fever due to epidural analgesia in 20% of women in labour, demonstrating counterregulated free mtDNA and nDNA. Further work is urgently required to understand the connections between the ERMF occurrence and circulating cell-free mtDNA as a potential source of sterile inflammation.

TRIAL REGISTRATION

NCT0405223 on clinicaltrials.gov (registered on 25/07/2019).

Local anesthetic delivery systems for the management of postoperative pain

Postoperative pain (POP) is a major clinical challenge. Local anesthetics (LAs), including amide-type LAs, ester-type LAs, and other potential ion-channel blockers, are emerging as drugs for POP management because of their effectiveness and affordability. However, LAs typically exhibit short durations of action and prolonging the duration by increasing their dosage or concentration may increase the risk of motor block or systemic local anesthetic toxicity. In addition, techniques using LAs, such as intrathecal infusion, require professional operation and are prone to catheter displacement, dislodgement, infection, and nerve damage. With the development of materials science and nanotechnology, various LAs delivery systems have been developed to compensate for these disadvantages. Numerous delivery systems have been designed to continuously release a safe dose in a single administration to ensure minimal systemic toxicity and prolong pain relief. LAs delivery systems can also be designed to control the duration and intensity of analgesia according to changes in the external trigger conditions, achieve on-demand analgesia, and significantly improve pain relief and patient satisfaction. In this review, we summarize POP pathways, animal models and methods for POP testing, and highlight LAs delivery systems for POP management. STATEMENT OF SIGNIFICANCE: Postoperative pain (POP) is a major clinical challenge. Local anesthetics (LAs) are emerging as drugs for POP management because of their effectiveness and affordability. However, they exhibit short durations and toxicity. Various LAs delivery systems have been developed to compensate for these disadvantages. They have been designed to continuously release a safe dose in a single administration to ensure minimal toxicity and prolong pain relief. LAs delivery systems can also be designed to control the duration and intensity of analgesia to achieve on-demand analgesia, and significantly improve pain relief and patient satisfaction. In this paper, we summarize POP pathways, animal models, and methods for POP testing and highlight LAs delivery systems for POP management.

Targeted local anesthesia: a novel slow-release Fe3O4-lidocaine-PLGA microsphere endowed with a magnetic targeting function

PURPOSE

Lidocaine microspheres can prolong the analgesic time to 24-48 h, which still cannot meet the need of postoperative analgesia lasting more than 3 days. Therefore, we added Fe3O4 to the lidocaine microspheres and used an applied magnetic field to attract Fe3O4 to fix the microspheres around the target nerves, reducing the diffusion of magnetic lidocaine microspheres to the surrounding tissues and prolonging the analgesic time.

METHODS

Fe3O4-lidocaine-PLGA microspheres were prepared by the complex-emulsion volatilization method to characterize and study the release properties in vitro. The neural anchoring properties and in vivo morphology of the drug were obtained by magnetic resonance imaging. The nerve blocking effect and analgesic effect of magnetic lidocaine microspheres were evaluated by animal experiments.

RESULTS

The mean diameter of magnetically responsive lidocaine microspheres: 9.04 ± 3.23 μm. The encapsulation and drug loading of the microspheres were 46.18 ± 3.26% and 6.02 ± 1.87%, respectively. Magnetic resonance imaging showed good imaging of Fe3O4-Lidocain-PLGA microspheres, a drug-carrying model that slowed down the diffusion of the microspheres in the presence of an applied magnetic field. Animal experiments demonstrated that this preparation had a significantly prolonged nerve block, analgesic effect, and a nerve anchoring function.

CONCLUSION

Magnetically responsive lidocaine microspheres can prolong analgesia by slowly releasing lidocaine, which can be immobilized around the nerve by a magnetic field on the body surface, avoiding premature diffusion of the microspheres to surrounding tissues and improving drug targeting.

Laparoscopic vs. ultrasound-guided transversus abdominis plane (TAP) block in colorectal surgery: a systematic review and meta-analysis of randomized trials

BACKGROUND

The transversus abdominis plane block (TAPB) is effective for postoperative pain management in patients undergoing colorectal surgery. However, evidence regarding the optimal delivery method, either laparoscopic (L-TAPB) or ultrasound-guided (U-TAPB) is lacking. Our study aimed to compare the effectiveness of these delivery methods.

METHODS

We carried out a literature search of PubMed, Cochrane Library, Web of Science, and Google Scholar databases to include randomized studies comparing patients receiving either L-TAPB or U-TAPB during minimally invasive colorectal surgery. The primary endpoint was opioid consumption in the first 24 h after surgery. Risk of bias was assessed with the RoB-2 tool. Effect size was estimated for each study with 95% confidence interval and overall effect measure was estimated with a random effect model.

RESULTS

The literature search revealed 294 articles, of which four randomized trials were eligible. A total of 359 patients were included, 176 received a L-TAPB and 183 received a U-TAPB. We established the non-inferiority of L-TAPB, as the absolute difference of - 2.6 morphine-mg (95%CI - 8.3 to 3.0) was below the pooled non-inferiority threshold of 8.1 morphine-mg (low certainty level). No difference in opioid consumption was noted at 2, 6, 12, and 48 h (low to very low certainty level). Postoperative pain, nausea and vomiting were similar between groups at different timepoints (low to very low certainty level). No TAPB-related complications were recorded. Finally, the length of hospital stay was similar between groups.

CONCLUSION

For postoperative multimodal analgesia both L-TAPB and U-TAPB may result in little to no difference in outcome in patients undergoing colorectal surgery. Registration Prospero CRD42023421141.

Effects of epinephrine, lidocaine, and prilocaine on viability and differentiation capacity of human adipose stem cells

INTRODUCTION

Local anesthetics (LAs) are routinely administered in plastic and reconstructive surgery, e.g., as tumescent anesthesia adjunct in liposuction. Historically, these substances were assumed to act cytotoxically. Thus, the application of LA was avoided when handling adipose stem cells (ASCs). We recently determined that most LAs are not cytotoxic when ASCs are exposed to concentrations used for tumescent liposuction. However, there is limited information when combining LA with epinephrine and about the effects of prilocaine on ASCs.

METHODS

We analyzed the effects of prilocaine or lidocaine in co-exposure with epinephrine on the viability of primary human ASCs, i.e., proliferation, metabolic activity, and cytotoxicity, using crystal violet-staining, PrestoBlue®-, and WST-1 assay. We quantified the impact of short-term incubation of lidocaine and epinephrine on the differentiation of ASCs into the adipogenic, chondrogenic, and osteogenic lineage.

RESULTS

After 2 h, prilocaine (10 mM) significantly reduced metabolic activity and cell numbers, whereas lidocaine only inhibited metabolic activity. After 6 h, prilocaine (10 mM) and lidocaine significantly decreased metabolic activity as well as cell numbers. The application of high concentrations of epinephrine did not affect cell numbers but diminished metabolic activity. Combining lidocaine with epinephrine had no additional cytotoxic effect. Differentiation into the chondrogenic lineage was significantly inhibited by epinephrine.

CONCLUSIONS

Deducing from our data, neither lidocaine combined with epinephrine nor prilocaine has a cytotoxic impact on ASCs in vitro at concentrations equivalent to those in tumescent anesthesia and has no long-lasting effect on the differentiation capacity of ASCs into the osteogenic and adipogenic lineage.

Assessment of cardiovascular alterations and catecholamines serum concentration after oral surgery in patients receiving local anesthetics with epinephrine: a randomized, blind, controlled clinical trial

OBJECTIVES

A randomized controlled clinical trial was developed to evaluate the cardiovascular effects of local anesthetics with vasoconstrictors (LAVC) in healthy and hypertensive patients undergoing teeth extraction with lidocaine 2% with epinephrine 1:100,000.

MATERIALS AND METHODS

Twenty patients were divided into control (CG - normotensive patients) and experimental groups (EG - hypertensive patients). The variables analyzed were heart rate (HR), oxygen saturation (SO2), systolic and diastolic blood pressure (SBP and DBP), serum catecholamine concentration (dopamine, epinephrine, and norepinephrine), ventricular and supraventricular extrasystoles (VES and SVES respectively), and ST segment depression. Data was obtained in three different moments (initial, trans, and final). Blood samples were taken to measure the catecholamines, and a Holter device was used to measure data from the electrocardiogram including a 24-h postoperative evaluation period. The Mann-Whitney test was used to identify differences between the two groups, and the Friedman test with the adjusted Wilcoxon posttest was used for intragroup evaluation for repeated measures.

RESULTS

The EG presented a lower O2S in the initial period (p = 0,001) while the sysBP showed a statistical difference for the three evaluation periods with the EG presenting the highest values. The VES was higher for the EG during the 24-h postoperative evaluation period (p = 0,041). The SVES and the serum catecholamines showed were similar between the groups. The intragroup analysis revealed significant statistical difference for the sysBP in the EG with the trans period presenting the highest measurements. The extrasystole evaluation showed that the 24-h postoperative period presented most events with only the CG not presenting statistical difference for the variable VES during this period (p = 0,112). No ST segment depression was noticed for both groups.

CONCLUSIONS

Teeth extraction with LAVC can be safely executed in hypertensive patients. Blood pressure should be monitored in these patients since the sysBP presented significant differences during the surgical procedures. Cardiac arrhythmia and the serum catecholamines concentration levels seem not to be altered by the surgical procedure. Also, serum catecholamines do not influence cardiovascular changes in this type of surgery.

CLINICAL RELEVANCE

LAVC can be safely used in hypertensive patients and does not increase the risk of arrhythmias or cardiac ischemia.

The effect of warming ropivacaine on ultrasound-guided subgluteal sciatic nerve block: a randomized controlled trial

BACKGROUND

There is a long latent period for the sciatic nerve block before a satisfactory block is attained. Changes in the temperature of local anesthetics may influence the characters of the peripheral nerve block. This study was designed to evaluate the effect of warming ropivacaine on the ultrasound-guided subgluteal sciatic nerve block.

METHODS

Fifty-four patients for distal lower limbs surgery were randomly allocated into warming group (group W, n = 27) or room tempeture group (group R, n = 27) with the ultrasound-guided subgluteal sciatic nerve block. The group W received 30 ml of ropivacaine 0.5% at 30℃ and the group R received 30 ml of ropivacaine 0.5% at 23℃. The sensory and motor blockade were assessed every 2 min for 30 min after injection. The primary outcome was the onset time of limb sensory blockade.

RESULTS

The onset time of sensory blockade was shorter in group W than in group R (16 (16,18) min vs 22 (20,23) min, p < 0.001), and the onset time of motor blockade was also shorter in group W than in group R (22 (20,24) min vs 26 (24,28) min, p < 0.001). The onset time of sensory blockade for each nerve was shorter in group W than in group R (p < 0.001). No obvious differences for the duration of sensory and motor blockade and the patient satisfaction were discovered between both groups. No complications associated with nerve block were observed 2 days after surgery.

CONCLUSIONS

Warming ropivacaine 0.5% to 30℃ accelerates the onset time of sensory and motor blockade in the ultrasound-guided subgluteal sciatic nerve block and it has no influence on the duration of sensory and motor blockade.

TRIAL REGISTRATION

The trial was registered on October 3, 2022 in the Chinese Clinical Trial Registry ( https://www.chictr.org.cn/bin/project/edit?pid=181104 ), registration number ChiCTR2200064350 (03/10/2022).

Encapsulation of Lidocaine nanoparticles in Gadus morhua derived lipoic acid

Local Anesthetics are used clinically for anesthesia and analgesia either following surgery or for management of acute and chronic pain conditions. Liposomal Encapsulation aids in improved delivery at the tissue level. This paper deals with formulation and characterization of Gadus morhua derived liposome encapsulated Lidocaine nanoparticles.

Materials and methods

Water Soluble liposomes were synthesized and encapsulated to lidocaine. The prepared liposomes were assessed using field emission scanning electron microscope, TEM, FTIR, Zetapotential, Anti-inflammatory property and Drug release kinetics.

Results

The structural and morphological characters of the conjugated liposomes were studied using SEM & TEM, surface charge Zetapotential. The cumulative drug release was studied for up to 72 h in which more than 70 % of the drug was released from the Liposomal nanoparticles. FTIR revealed similar functional groups like the control. Stability of the drug was superior than the control.

Conclusion

Liposomal conjugation delays the drug release which can be used in slow release applications. Improving the drug release kinetics can be advantageous in many chronic pain conditions. Additionally, the changes in the functional groups can also aid in reduction or masking of bitterness.

When it is too much: Identifying butamben excess on the surface of pharmaceutical preformulation samples by Raman mapping

Butamben is a topical local anesthetic which formulation in lipid-based drug delivery systems (DDS) is challenging due to its affinity for hydrophilic excipients. This means that a medium polarity excipient is preferred for the development of a stable nanostructured lipid carrier (NLC) formulation. In turn, in NLC, the type and number of excipients will determine the active pharmaceutical ingredient (API) solubility and the maximum drug upload. To solve this dilemma and get the best formulation, a throughout screening study to evaluate API solubilization in different excipients was carried out. Subsequently, excipients with different solubilization capacities were selected for microscopic evaluation by Raman mapping, and in turn analysis of the distributional homogeneity index (DHI) and standard deviation of the histograms allowed solving the posed question. Design of experiments (DoE) was employed to understand better the interactions between the excipients; linear and higher-order models were obtained with R2 above of 0.8824. Even though DHI is a good parameter to be used as response, an API concentration higher than 30% (w/w) provided a homogeneous surface in case of good miscibility and, in this case, this parameter needs to be employed with an inspection and/or evaluation of other parameters. A curve of concentration vs. mean scores of images proved to be an alternative to identify the saturation/limit of linear range.

Micro-pharmacokinetics of lidocaine and bupivacaine transfer across a myelinated nerve fiber

BACKGROUND

The aim of the present study was to predict the time to onset and duration of action of two local anesthetics (lidocaine and bupivacaine) based on experimental dimensions of a typical nerve and experimental octanol/water partition coefficients.

METHODS

We began our compilation of experimental data with a numerical solution of the Smoluchowski equation for the transfer of lidocaine and bupivacaine across the axon membrane in the region of the node of Ranvier (axolemma) and across the Schwann cell. The difference between the aqueous and lipid environments of the neuron was simulated by including the coordinate-dependent chemical potential. In the second step, the permeation rates calculated using the diffusion equation were used to solve a system of four ordinary differential equations. This approach allowed us to simulate the cellular environment for a longer time and to compare our model with pharmacokinetic properties (time to onset and duration of action) of local anesthetics from the literature. The behavior of local anesthetics under physiological conditions and in case of local acidosis was also simulated.

RESULTS

We demonstrated that local anesthetics cross the axolemma in a time span of less than 1 μs. The time to onset of action, controlled by diffusion from the epineurium to an axon with a typical distance of 500 μm, was 167 s and 186 s for lidocaine and bupivacaine, respectively. The calculated half-life, which is a measure of the duration of action, was 41 min and 328 min for lidocaine and bupivacaine, respectively.

CONCLUSIONS

Duration of action is controlled by the storage capacity of lipophilic compartments around the axon, which is higher for bupivacaine but lower in local acidosis. For the latter case, the literature, including textbooks, provides a misinterpretation, namely that protonated species cannot penetrate the membrane.

Dexamethasone and dexmedetomidine as adjuvants to ropivacaine do not prolong analgesia in wound infiltration for lumbar spinal fusion: a prospective randomized controlled study

BACKGROUND AND OBJECTIVES

Local anesthetics (LAs) are widely used to infiltrate into surgical wounds for postoperative analgesia. Different adjuvants like dexamethasone and dexmedetomidine, when added to LA agents, could improve and prolong analgesia. The aim of this trial was to evaluate the analgesic efficacy and opioid-sparing properties of dexamethasone and dexmedetomidine when added to ropivacaine for wound infiltration in transforaminal lumbar interbody fusion (TLIF).

METHODS

We conducted a controlled study among 68 adult patients undergoing TLIF, which was prospective, randomized and double-blind in nature. The participants were divided into four equal groups at random. Group R was given 150 mg of 1% ropivacaine (15 mL) and 15 mL of normal saline. Group R + DXM received 150 mg of 1% ropivacaine (15 mL) and 10 mg of dexamethasone (15 mL). Group R + DEX received 150 mg of 1% ropivacaine (15 mL) and 1 µg/kg of dexmedetomidine (15 mL). Lastly, group R + DXM + DEX was given 150 mg of 1% ropivacaine (15 mL), 10 mg of dexamethasone and 1 µg/kg of dexmedetomidine (15 mL). The primary focus was on the length of pain relief provided. Additionally, secondary evaluations included the amount of hydromorphone taken after surgery, the numerical rating scale and safety assessments within 48 h after the operation.

RESULTS

Based on the p value (P > 0.05), there was no significant variance in the duration of pain relief or the total usage of hydromorphone after surgery across the four groups. Similarly, the numerical rating scale scores at rest and during activity at 6-, 12-, 24- and 48-h post-surgery for all four groups showed no difference (P > 0.05). However, the incidence of delayed anesthesia recovery was slightly higher in group R + DEX and group R + DXM + DEX when compared to group R or group R + DXM. Furthermore, there were no significant differences between the four groups in terms of vomiting, nausea, dizziness or delayed anesthesia recovery.

CONCLUSION

For wound infiltration in TLIF, the addition of dexamethasone and dexmedetomidine to ropivacaine did not result in any clinically significant reduction in pain or opioid consumption and could prompt some side effects.

Observational and descriptive analysis of broken dental needles: a case series

PURPOSE

To discuss potential causes of broken dental needles during dental anesthesia and features of this complication, including the anatomical location of fragments in tissues, symptoms, complications, and therapeutic approaches.

METHODS

Twelve cases of broken dental needles occurring during dental anesthesia and subsequently referred to Hospital de Base do Distrito Federal, Brazil, between 1992 and 2019 were selected. In addition, similar cases reported in the literature over the past 50 years were reviewed.

RESULTS

Needle fractures occur most frequently during inferior alveolar nerve blocks and in younger patients. The leading cause is unexpected patient movement during the anesthetic procedure. The needle fragment is most commonly found in the pterygomandibular space or the deep spaces of the head and neck region. Needle migration is a particular concern; although rare, it is unpredictable and potentially life-threatening.

CONCLUSIONS

Needle fracture is an intraoperative complication which has the potential to cause severe patient damage. It is essential that practitioners have knowledge of this possible complication and understand the technical considerations for its prevention. The existing literature and the results of this case series analysis suggest that removal of the fractured needle fragment should be attempted as soon as possible.

Paresthesia in dentistry: The ignored neurotoxicity of local anesthetics

Local anesthetics are frequently used by dentists to relieve localized discomfort of the patient and improve treatment conditions. The risk of paresthesia after local anesthesia is frequently encountered in dental clinics. The neurotoxicity of local anesthetics is a disregarded factor in paresthesia. The review summarizes the types of common local anesthetics, incidence and influencing factors of paresthesia after local anesthesia, and systematically describes the neurotoxicity mechanisms of dental local anesthetic. Innovative strategies may be developed to lessen the neurotoxicity and prevent paresthesia following local anesthesia with the support of a substantial understanding of paresthesia and neurotoxicity.

Local anesthetics systemic toxicity in children: analysis of the French pharmacovigilance database

PURPOSE

To characterize clinical profile of pediatric local anesthetic (LA) systemic toxicity (LAST) and to identify determinants of life-threatening outcomes.

METHODS

Spontaneous reports notified to the French Pharmacovigilance Network were retrieved and followed by a case-by-case review, according to the following criteria: LA as suspected drug, age < 18 years, adverse drug reactions related to nervous system, cardiac, respiratory, psychiatric or general disorders. Multivariate logistic regression analysis was performed to identify factors leading to life-threatening reaction (i.e. continuous seizures or cardiorespiratory arrest).

RESULTS

Among 512 cases retrieved, 64 LAST cases were included (neonates 11%, infants 30%, children 36%, adolescents 23%) mainly involving lidocaine (47%), lidocaine + prilocaine (22%) and ropivacaine (14%). Toxicity profiles were neurological (58%), cardiac (11%) or mixed (20%) and 7 patients (11%) developed methemoglobinemia. LAST was life-threatening for 23 patients (36%) and 2 patients died. Doses were above recommendations in 26 patients (41%) and were not different between life-threatening and non-life-threatening cases. The context of use (general and orthopedic surgery, p = 0.006) and the type of LA agent (lidocaine, p = 0.016) were independently associated with a life-threatening outcome.

CONCLUSION

In this national retrospective analysis, LAST in children appear to be a rare event. Neurological and cardiac signs were the most frequently reported reactions. LAST in children can be life-threatening, even at therapeutic doses. Although a fatal outcome may anecdotally occur, the vast majority of patients recovered after appropriate medical care.

Resistance to local anesthetics: Truth or myth?

The report of anesthetic technique failure is crucial and the etiology of the problem should be determined. We describe a case of locoregional anesthesia failure, in which, after excluding its most common causes, the resistance to local anesthetics was considered as the most probable clinical hypothesis. For this reason, a genetic test was performed, as well as the efficacy of other local anesthetics was evaluated, constituting a different approach in the cases of locoregional anesthesia failure. True resistance to local anesthetics is difficult to diagnose so information about this is scarce in the literature. One of the proposed causes is a mutation of sodium channels where local anesthetics bind. If not recognized, the application of locorregional anesthesia in this patient's condition can lead to unpleasant experiences and unnecessary risks, related to toxic levels of local anesthetics. For this reason, the resistance to local anesthetics should be always precluded in cases of strong clinical suspicion. This approach could be applied in similar cases.

Inflammation and subsequent nociceptor sensitization in the bone marrow are involved in an animal model of osteoarthritis pain

AIMS

This study aimed to determine whether pathological changes in the bone marrow cause Osteoarthritis (OA) pain based on magnetic resonance imaging (MRI), immunohistochemistry, and electrophysiology.

MAIN METHODS

Adjuvant-induced arthritis (AIA) was achieved by injecting 150 μL of complete Freund's adjuvant into the right knee joints of male Sprague-Dawley rats. AIA rats were compared with saline-injected rats.

KEY FINDINGS

AIA significantly induced mechanical hyperalgesia and spontaneous pain in the right hind paw 1-14 days after induction. Intratibial injection of 50 μL of 1 % lidocaine significantly suppressed AIA-induced mechanical hyperalgesia (p = 0.0001) and spontaneous pain (p = 0.0006) 3 days after induction. In T2-weighted MRI, AIA induced high-signal intensity within the proximal tibial metaphysis, and the mean T2 values in this area significantly increased on days 3 (p = 0.0043) and 14 (p = 0.0012) after induction. AIA induced intraosseous edema and significantly increased the number of intraosseous granulocytes on days 3 (p < 0.0001) and 14 (p < 0.0001) after induction. The electrophysiological study on days 3-7 after induction showed significantly increased spontaneous firing rates (p = 0.0166) and evoked responses to cutaneous stimuli (brush, p < 0.0001; pinching, p = 0.0359) in the right hind paw plantar surface and intratibial stimuli (p = 0.0002) in wide-dynamic-range neurons of the spinal dorsal horn.

SIGNIFICANCE

Intraosseous changes caused by OA induce hypersensitivity in the sensory afferents innervating bone marrow may be involved in OA pain. Novel bone marrow-targeted therapies could be beneficial for treating OA pain.

[Transrectal vs. transperineal fusion biopsy of the prostate : Time to switch to the perineal technique-comparison of methods and description of the transperineal procedure under local anesthesia]

The clinical and histological diagnosis of prostate cancer is a crucial aspect of the routine work of a urologist. The high prevalence of multiresistant microorganisms leads to an increased incidence of sepsis after transrectal prostate biopsy. It requires a switch from the still gold-standard method to the transperineal fusion biopsy procedure after multiparametric prostate magnetic resonance imaging (MRI). This article provides an overview of the most important differences between the two methods and gives a detailed methodological description of transperineal fusion biopsy under local anesthesia.

The modified pectoral nerve block versus bi-level erector spinae plane block for postoperative analgesia after radical mastectomy surgery: A prospective, randomized, controlled trial

Background

Regional anesthesia techniques constitute an important part of successful analgesia strategies, and in the perioperative care of breast surgery patients. The advent of ultrasound-guided regional anesthesia led to the development of fascial plane blocks. The abundance of blocks available for postoperative analgesia in breast surgery has increased the accessibility of regional anesthesia but has also created the dilemma of choice. This study compared the analgesic efficacy of ultrasound-guided modified pectoral nerve (PECS) block and erector spinae plane block (ESPB) in patients undergoing modified radical mastectomy (MRM).

Method

Seventy women were enrolled for the study. After exclusion, 67 female patients undergoing MRM were finally analyzed. Ultrasound-guided PECS block and ESPB were performed with 30 ml 0.25% bupivacaine in this prospective, double-blind, randomized control trial. Postoperative morphine and pain scores were compared between the groups.

Results

Postoperative total morphine consumption in the first 24 h was significantly higher in the PECS group (P = 0.000). The ESPB group exhibited significantly reduced morphine consumptions at all postoperative time points. Numeric rating scale scores were lower in the ESPB group at postoperative 6, 12, and 24 h at rest and when coughing.

Conclusions

Ultrasound guided bi-level ESPB provided better postoperative analgesia compared to PECS block after radical mastectomy surgery.

Lack of concentration-dependent local toxicity of highly concentrated (5%) versus conventional 0.5% bupivacaine following musculoskeletal surgery in a rat model

PURPOSE

Various sustained-release formulations incorporate high bupivacaine concentrations but data on local toxicity is lacking. This study explores local toxic effects of highly concentrated (5%) bupivacaine compared to clinically used concentrations in vivo following skeletal surgery, to assess the safety of sustained-release formulations with high bupivacaine concentrations.

METHODS

Sixteen rats underwent surgery, in which screws with catheters affixed were implanted in the spine or femur in a factorial experimental design, allowing single-shot or continuous 72 h local administration of 0.5%, 2.5% or 5.0% bupivacaine hydrochloride. During the 30-day follow-up, animal weight was recorded and blood samples were obtained. Implantation sites underwent histopathological scoring for muscle damage, inflammation, necrosis, periosteal reaction/thickening and osteoblast activity. Effects of bupivacaine concentration, administration mode and implantation site on local toxicity scores were analyzed.

RESULTS

Chi-squared tests for score frequencies revealed a concentration-dependent decrease in osteoblast count. Moreover, spinal screw implantation led to significantly more muscle fibrosis but less bone damage than femoral screw implantation, reflecting the more invasive muscle dissection and shorter drilling times related to the spinal procedure. No differences between bupivacaine administration modes regarding histological scoring or body weight changes were observed. Weight increased, while CK levels and leukocyte counts decreased significantly during follow-up, reflecting postoperative recovery. No significant differences in weight, leukocyte count and CK were found between interventional groups.

CONCLUSION

This pilot study found limited concentration-dependent local tissue effects of bupivacaine solutions concentrated up to 5.0% following musculoskeletal surgery in the rat study population.

DoE development of ionic gradient liposomes: A successful approach to improve encapsulation, prolong anesthesia and decrease the toxicity of etidocaine

Etidocaine (EDC) is a long-acting local anesthetic of the aminoamide family whose use was discontinued in 2008 for alleged toxicity issues. Ionic gradient liposomes (IGL) are nanostructured carriers for which an inner/outer gradient of ions increases drug upload. This work describes IGL_EDC, a formulation optimized by Design of Experiments, composed of hydrogenated soy phosphatidylcholine:cholesterol:EDC, and characterized by DLS, NTA, TEM/Cryo-TEM, DSC and ¹H NMR. The optimized IGL showed significant encapsulation efficiency (41 %), good shelf stability (180 days) and evidence of EDC interaction with the lipid bilayer (as seen by DSC and ¹H NMR results) that confirms its membrane permeation. In vitro (release kinetics and cytotoxicity) tests showed that the encapsulation of EDC into the IGL promoted sustained release for 24 h and decreased by 50 % the intrinsic toxicity of EDC to Schwann cells. In vivo IGL_EDC decreased the toxicity of EDC to Caenorhabditis elegans by 25 % and extended its anesthetic effect by one hour, after infiltrative administration, at clinically used (0.5 %) concentration, in rats. Thus, this novel drug delivery system is a promise for the possible reintroduction of EDC in clinics, aiming at the control of operative and postoperative pain.

Evaluation of distal skin temperature and tissue oxygen saturation determined by near-infrared spectroscopy for predicting ultrasound-guided lateral infraclavicular block success

BACKGROUND

Changes in tissue oxygen saturation determined by near-infrared spectroscopy (NIRS) may help predict and determine the success of a lateral infraclavicular (LIC) block.We investigated whether evaluation of tissue oxygen saturation determined by NIRS couldbe an indicator of LIC block success.

METHODS

Forty patients scheduled for hand or forearm surgery under LIC block were studied. NIRS sensors were placed on the ventral aspect of both mid-forearms, and the contralateral hand was used as the control group. NIRS values were recorded before the block andat regular intervals during the following 30 min.

RESULTS

NIRS values were significantly higher in the successfully blocked patients whencompared to the complete failure, partial failure, and contralateral hand groups at the 10thmin. In the successfully blocked patients, NIRS values (mean ± SD [change in %]) increasedby 11.09 ± 4.86 (16.03%), 15.00 ± 4.53 (21.76%), 16.35 ± 5.14 (23.77%), 16.38 ± 4.88(23.85%), 16.67 ± 5.04 (24.29%), and 16.96 ± 5.71 (24.78%), respectively, from baselineto 5, 10, 15, 20, 25, and 30 min. ΔTs values were significantly higher in the successfullyblocked patients than in the complete failure patients and contralateral hand at the 30thmin. However, there was no statistically significant difference when comparing ΔTs values ofsuccessful block and partial failure block patients at the 30th min.

CONCLUSIONS

We conclude that measurement of tissue oxygen saturation by NIRS withinthe scope of evaluation of the lateral infraclavicular block is a rapid, effective, and applicabletechnique.

Chronic Therapy-Resistant Neck Pain in a Fifty-Year-Old Man: The Role of Partially Impacted Third Molars - Case Report and New Pathophysiological Insights

BACKGROUND

Inflammatory and mechanical stimuli in tooth/jaw pathologies can have far-reaching consequences via trigeminal and autonomic circuitry and can cause systemic (e.g., autoimmune) diseases and pain conditions outside the tooth/jaw region. In addition to a case report, we also describe new pathophysiological findings.

CASE REPORT

We report on a patient with chronic, therapy-resistant neck pain whose cause lied in the tooth/jaw region, specifically, in wisdom teeth with space problems, and partially impacted. The tooth/jaw area itself was not painful; however, neck pain developed via the nucleus spinalis n. trigemini which extends into the cervical medulla. Surgical restoration of the wisdom teeth and subsequent neural therapy treatment of the extraction scars provided permanent pain relief.

CONCLUSION

In case of therapy-resistant neck pain (among others), it is worthwhile to look for pathologies in the dental/jaw area, possibly allowing for a causal therapy.

Establishment of an animal model of sciatic nerve injury induced by local anesthetics

Peripheral neurotoxicity injury caused by local anesthetics is a common complication of clinical anesthesia. The study of its mechanism is helpful to prevent and treat the neurotoxic injury of local anesthetics. Previous studies on peripheral neurotoxicity injury caused by local anesthetics have mainly focused on in vitro cell experiments. Due to the lack of an animal model of peripheral neurotoxicity damage caused by local anesthetics, there are few in vivo experimental studies regarding this topic. Herein, 1% ropivacaine hydrochloride was injected into the sciatic nerve by direct incision and exposure of the sciatic nerve to create a local anesthetic neurotoxic injury model. The results showed that 1% ropivacaine hydrochloride could reduce the lower limb motor score and mechanical paw withdrawal threshold in mice 48 hours after injection. Pathological sections showed that 48 hours after treatment with 1% ropivacaine hydrochloride, the sciatic nerve showed increased axonal edema and degeneration, edema between nerve fiber bundles, increased degeneration of axon and myelin sheath vacuoles, edema of nerve bundle membrane and local degeneration and necrosis, and a large number of inflammatory cells around the nerve adventitia were soaked. The above results show that under open vision, 1% ropivacaine hydrochloride can cause injury to the sciatic nerve after 48 h of treatment, which can simulate the neurotoxic damage of local anesthetics. This animal model provides a research tool for studying the mechanism of neurotoxic injury caused by local anesthetics.

Treatment of Pain in Fish

This chapter provides an overview of our current understanding of clinical analgesic use in fish. Recently, the efficacy and pharmacokinetics of several analgesic drugs for use in fish have been investigated, and the most important data indicates that μ-opioid agonist drugs (e.g, morphine) are consistently effective as analgesics across fish species. In addition, bath application of some analgesic drugs may be useful, which affords multiple methods for delivering analgesics to fish. Although few published studies of non-steroidal anti-inflammatory drugs administered to fish show promise, we have much to learn about the analgesic efficacy of most drugs in this class.

Treatment of Pain in Reptiles

This chapter provides an overview of our current understanding of clinical analgesic use in reptiles. Currently, μ-opioid agonist drugs are the standard of care for analgesia in reptiles. Reptile pain is no longer considered a necessary part of recovery to keep the reptile from becoming active too early. Rather, treating pain allows for the reptile to begin normalizing their behavior. This recognition of pain and analgesia certainly benefits our reptile patients and greatly improves reptile welfare, but it also benefits our students and house officers, who will carry the torch and continue to demand excellence in reptile medicine.

Effect of species, concentration and volume of local anesthetics on intervertebral disk degeneration in rats with discoblock

PURPOSE

Discoblock is effective in relieving discogenic low back pain, but it can also cause intervertebral disk degeneration (IDD). The effect of species, concentration and volume of local anesthetics on IDD with discoblock have not been reported. The purpose was to study the effect of species, concentration and volume of local anesthetics on IDD in rats undergoing discoblock.

METHODS

The effects of local anesthetics on nucleus pulposus cell (NPC) viability in vitro were studied. NPCs were exposed to lidocaine, bupivacaine and ropivacaine at different concentrations. NPC viability was measured. The least cytotoxic local anesthetic was used in vivo. The concentration and volume of local anesthetics on IDD in rat with discoblocks were tested in vivo. Detection indicators included X-ray, MRI, water content of the disk and histological changes.

RESULTS

The toxicity of local anesthetics to NPCs was dose and time dependent, and the cytotoxicity of different local anesthetics was different. Among the three local anesthetics, ropivacaine was the least toxic to NPCs. The effect of ropivacaine concentration on IDD was not significant, as detected by X-ray, MRI, disk water content and histology (P < 0.05). The volume of ropivacaine has a significant effect on IDD, as supported by X-ray, MRI, disk water content and histology (P < 0.05). Acupuncture itself significantly increased IDD, as detected by MRI, disk water content and histology (P < 0.05).

CONCLUSION

Ropivacaine should be selected for its low cytotoxicity. A lower volume and slow injection speed should be used to reduce IDD during discoblock.

A rare case of facet joint synovial cyst connected to the intrathecal space: a case report

Unexpected injection of local anesthetics into the intrathecal space can cause adverse effects, such as hypotension, shortness of breath, bradycardia, numbness or weakness, nausea and vomiting and serious complications, such as respiratory arrest, loss of consciousness and cardiac arrest. In this study, we report a case of a 68-year-old woman with a facet joint synovial cyst connected to the intrathecal space. The patient's clinical symptoms and radiological findings were consistent with those of a facet joint synovial cyst; however, during facet joint synovial cyst aspiration, it was found that the cyst was connected to the intrathecal space. Our experience shows that during the procedure of facet joint injection and facet joint synovial cyst aspiration, local anesthetics may be inadvertently injected intrathecally. Although this is highly uncommon, it can lead to serious side effects, such as total spinal anesthesia. Therefore, we present this case, along with a brief literature review.

Combined femoral-obturator-sciatic nerve block has superior postoperative pain score and earlier ambulation as compared to spinal anaesthesia for arthroscopic anterior cruciate ligament reconstruction

PURPOSE

Peripheral nerve blocks can be a suitable alternative to central neuraxial blockage, as the sole anaesthetic agent for better early postoperative outcomes, decreased hospital stay and earlier mobilisation after anterior cruciate ligament reconstruction (ACLR) surgery. The purpose of this study was to compare consciousness during the procedure, pain during early postoperative period (< 7 days), and perioperative outcomes following ACLR using combined sciatic, femoral, and obturator nerve blocks compared to the spinal anaesthesia.

METHODS

This was a prospective case-control study including patients between 18 and 55 years of age, with anterior cruciate ligament (ACL) injury confirmed clinically and radiologically and undergoing ACLR. Patients were allocated in the two groups alternatively, group 1 included patients who received combined nerve blocks, and group 2 included patients who received spinal anaesthesia for the surgery. The sensory effect, motor effect, adequacy of anaesthesia, perioperative analgesic use, duration of stay, postoperative pain (visual analogue scale 0-10 cm) and functional outcomes were noted.

RESULTS

There were 60 patients in each group. A total of seven patients in group 1 (11%) and two patients in group 2 (3%) needed conversion to general anaesthesia (n.s.). In group 1, out of 53 patients who underwent surgery, 26 patients had no perception of surgery in the joint, 17 patients had perception of manipulation of the knee joint, 4 patients had sense of touch, and 6 patients had sensation of pain in the knee (VAS scale less than 3). In group 2, out of 58 patients, 42 patients had no perception of surgery, 12 had a perception of manipulation of the knee joint, 2 had sense of touch, and 2 had sensation of pain in the knee. Blockage of sensory effect was significantly better in group 2 (p = 0.0001). However, the motor effect was comparable between the two groups (n.s.). Group 1 had significantly better pain scores 6, 12, and 18 h after the surgery. Moreover, patients in group 1 also had faster ambulation (mean difference of 5.5 h, p = 0.0001) and reduced hospital stay (mean difference of 8.4 h, p = 0.0001).

CONCLUSION

Combined sciatic, femoral, and adductor canal block is an effective sole anaesthetic modality for ACLR. The sensory effect was inferior when compared to spinal anaesthesia but sufficient for the procedure without the need for supplementation with any other anaesthetic modality. Patients receiving this combined nerve block had lesser early postoperative pain scores, earlier ambulation, and shorter hospital stay as compared to the spinal anaesthesia.

LEVEL OF EVIDENCE

Level 3.

Robust gelatin hydrogels for local sustained release of bupivacaine following spinal surgery

Adequate treatment of pain arising from spinal surgery is a major clinical challenge. Opioids are the mainstay of current treatment methods, but the frequency and severity of their side effects display a clear need for opioid-free analgesia. Local anesthetics have been encapsulated into sustained-release drug delivery systems to provide postoperative pain relief. However, these formulations are limited by rapid diffusion out of the surgical site. To overcome this limitation, we synthesized ring-shaped hydrogels incorporating bupivacaine, designed to be co-implanted with pedicle screws during spinal surgery. Hydrogels were prepared by riboflavin-mediated crosslinking of gelatin functionalized with tyramine moieties. Additionally, oxidized β-cyclodextrin was introduced into the hydrogel formulation to form dynamic bonds with tyramine functionalities, which enables self-healing behavior and resistance to shear. Feasibility of hydrogel implantation combined with pedicle screws was qualitatively assessed in cadaveric sheep as a model for instrumented spinal surgery. The in-situ crystallization of bupivacaine within the hydrogel matrix provided a moderate burst decrease and sustained release that exceeded 72 hours in vitro. The use of bupivacaine crystals decreased drug-induced cytotoxicity in vitro compared to bupivacaine HCl. Thus, the presented robust hydrogel formulation provides promising properties to enable the stationary release of non-opioid analgesics following spinal surgery. STATEMENT OF SIGNIFICANCE: Currently, postoperative pain following spinal surgery is mainly treated with opioids. However, the use of opioids is associated with several side effects including addiction. Here we developed robust and cytocompatible gelatin hydrogels, prepared via riboflavin-mediated photocrosslinking, that can withstand orthopedic implantation. The implantability was confirmed in cadaveric instrumented spinal surgery. Further, hydrogels were loaded with bupivacaine crystals to provide sustained release beyond 72 hours in vitro. The use of crystallized bupivacaine decreased cytotoxicity compared to bupivacaine HCl. The present formulation can aid in enabling opioid-free analgesia following instrumented spinal surgery.

Local anesthetics via multicomponent reactions

Local anesthetics occupy a prime position in clinical medicine as they temporarily relieve the pain by blocking the voltage-gated sodium channels. However, limited structural diversity, problems with the efficiency of syntheses and increasing toxicity, mean that alternative scaffolds with improved chemical syntheses are urgently needed. Here, we demonstrate an MCR-based approach both towards the synthesis of commercial local anesthetics and towards novel derivatives as potential anesthesia candidates via scaffold hopping. The reactions are efficient and scalable and several single-crystal structures have been obtained. In addition, our methodology has been applied to the synthesis of the antianginal drug ranolazine, via an Ugi three-component reaction. Representative derivatives from our libraries were evaluated as neuronal activity inhibitors using local field potential recordings (LFPs) in mouse hippocampal brain slices and showed very promising results. This study highlights new opportunities in drug discovery targeting local anesthetics.

Effect of Local Anesthetics on Dipole Potential of Different Phase Membranes: A Fluorescence Study

The molecular mechanism behind the action of local anesthetics is not well understood. Phenylethanol (PEtOH) is an ingredient of essential oils with a rose-like odor, and it has previously been used as a local anesthetic. In this work, we explored the effect of PEtOH on dipole potential in membranes representing biologically relevant phases, employing the dual-wavelength ratiometric method utilizing the potential-sensitive probe di-8-ANEPPS. Our results show that PEtOH reduces membrane dipole potential in membranes of all biologically relevant phases (gel, liquid-ordered, and fluid) in a concentration-dependent manner. To the best of our knowledge, these results constitute one of the early reports describing reduction of membrane dipole potential induced by local anesthetics, irrespective of membrane phase.

[Liposomal bupivacaine-No breakthrough in postoperative pain management]

One of the main limitations concerning the use of local anesthetics is due to their restricted duration of action. In recent years, liposomal formulations with prolonged release kinetics have been developed to extend the pharmacological duration of action of the 1‑stage peripheral regional anesthesia (single-shot procedure) and thus bring about a longer duration of action. The focus here is particularly on achieving postoperative freedom from pain for at least 24 h (or even better 48 h) and thus early mobilization of patients using on-demand medication causing (at most) minor local sensory blockade without causing motor impairments (at least that is the ideal). Therefore, methods of utilizing slow-release drugs as seen in liposomal carrier systems have experienced increasing scientific attention in the last few years. A common modern pharmacological example with a theoretically significantly longer duration of action is liposomal bupivacaine, an amide local anesthetic. Due to a multivesicular liposome structure, the retarded release of the active component bupivacaine HCl leads to a theoretical pharmacological effectiveness of up to 72 h. Previous studies consistently showed a safety profile comparable to conventional bupivacaine HCl. Liposomal bupivacaine has been approved by the U.S. Food and Drug Administration (FDA) under the trade name Exparel© (Pacira Pharmaceuticals, Parsippany, NJ, USA) since 2011; however, its use is currently limited to local wound infiltration, transverse abdominis plane (TAP) blocks, and interscalene nerve blocks of the brachial plexus. In 2020, the European Medicines Agency (EMA) also approved the use of liposomal bupivacaine for blockade of the brachial plexus or the femoral nerve and as a field block or for wound infiltration to treat postoperative pain. So far, studies on the clinical effectiveness of liposomal bupivacaine have been very heterogeneous and there have been no conclusive meta-analyses with sufficient rigor or significance. Recent systematic reviews and meta-analyses, combining the results of clinical studies regarding the analgesic efficiency of liposomal bupivacaine in different fields of application, consistently refuted any benefit of clinical relevance provided by the liposomal formulation. There is currently sufficient evidence to now end the ongoing debate around liposomal bupivacaine. The aim of this work is to give the reader a current, evidence-based overview of this substance.

Peripheral Nerve Block Complications in Children

Regional anesthesia, and in particular peripheral nerve block (PNB) techniques, complement existing anesthetic and pain management strategies and facilitate a comprehensively safer experience for the pediatric patient. Ultimately, the use of regional anesthesia cultivates a more satisfactory experience for all involved. Complication rates are very low, making PNBs a very safe option as proliferative incorporation of ultrasound technology has led to further enhancement of regional anesthesia safety and efficacy in the pediatric population.

Pain management with transdermal drug administration: A review

Pain management is an urgent issue to solve with complex mechanisms. Localized acute pain requires rapid and accurate delivery of drugs with less distribution in the blood circulation while chronic pain requires controlled release of drugs with long drug retention time. The transdermal route, a promising way with high patient compliance was known for painless delivery, long drug retention time, stable blood concentration, easily controlled dosage and release rate as well as the fewer side effects. This review presents transdermal route for pain management according to the different sites of action which drugs aim to reach, and illustrates different analgesic mechanisms, dosage forms, transdermal enhancements and clinical applications. In addition, the review concludes the difference of pain types and presents the future aims of pain management, thereby providing a reference for researches focusing on percutaneous analgesia.

Local Anesthetics, Local Anesthetic Systemic Toxicity (LAST), and Liposomal Bupivacaine

Local anesthetics have played a vital role in the multimodal analgesia approach to patient care by decreasing the use of perioperative opioids, enhancing patient satisfaction, decreasing the incidence of postoperative nausea and vomiting, decreasing the length of hospital stay, and reducing the risk of chronic postsurgical pain. The opioid-reduced anesthetic management for perioperative analgesia has been largely successful with the use of local anesthetics during procedures such as peripheral nerve blocks and neuraxial analgesia. It is important that practitioners who use local anesthetics are aware of the risk factors, presentation, and management of local anesthetic systemic toxicity (LAST).

Comparison of pericapsular nerve group (PENG) block with fascia iliaca compartment block (FICB) for pain control in hip fractures: A double-blind prospective randomized controlled clinical trial

BACKGROUND

Fascia iliaca compartment block (FICB) is a common regional analgesic strategy in hip fracture surgery but, recently it has been suggested that FICB may not provide enough analgesia. Pericapsular nerve group block (PENG) is a novel method for hip analgesia which its efficacy is not well established yet. The aim of this study was to the effect of the PENG block in the control of the hip fracture pain as well as to compare the effectiveness of the PENG compared with FICB.

HYPOTHESIS

The hypothesis of this study was that the PENG block could be a good alternative to the FICB in hip fracture analgesia.

MATERIALS AND METHODS

This randomized controlled clinical trial was conducted in the Imam- Hossein Hospital, Tehran, Iran; between 2018 and 2019. Hip fracture patients were randomly divided into two groups; Group A (n=22) received FICB and Group B (n=30) received PENG block.

RESULTS

There was no significant difference between VAS score before blocks procedure between two groups (p=0.37). After 15minutes of blocks and after 12hours of post-surgery, VAS score significantly reduced in the PENG block group compared with the FICB group (p=0.031; p=0.021, respectively). The first time of the analgesic consumption after surgery was significantly longer in the PENG block compared with the FCIB (p=0.007). Compared with the FICB group, the total dose of morphine consumption during 24hours significantly reduced in the PENG block (p=0.008).

CONCLUSION

PENG block is a good method in hip fractures analgesia and provides better analgesia than FICB. However, further studies with larger sample sizes are required to validate the efficacy and superiority of the PENG blocks over conventional techniques.

LEVEL OF EVIDENCE

I.

Potential Therapeutic Application of Local Anesthetics in Cancer Treatment

Local anesthetics are voltage-gated sodium channel blockers primarily administered locally or to the innervating nerves for anesthetic or analgesic purposes. In vitrol studies have found direct effects of local anesthetics on cancer cell, such as impacts on cancer cell proliferation, apoptosis, migration, invasion, and chemosensitivity, which involved multiple mechanisms. So far, in vivo evidence in the effect of local anesthetics on cancer cell lines is relatively lacking. Local and regional anesthesia administration has been reported to reduce postoperative pain and opioid use in cancer treatment. Additionally, regional anesthesia may reduce the perioperative stress response. However, the clinical therapeutic application of local anesthetics on cancer remains exploratory. In this review, we will discuss the direct and indirect effect of local anesthetics on cancer cells, and discuss the current evidence for the use of local anesthetics in the treatment of cancer.

Regulation of acute reflectory hyperinflammation in viral and other diseases by means of stellate ganglion block. A conceptual view with a focus on Covid-19

Whereas the autonomic nervous system (ANS) and the immune system used to be assigned separate functions, it has now become clear that the ANS and the immune system (and thereby inflammatory cascades) work closely together. During an acute immune response (e. g., in viral infection like Covid-19) the ANS and the immune system establish a fast interaction resulting in "physiological" inflammation. Based on our knowledge of the modulation of inflammation by the ANS we propose that a reflectory malfunction of the ANS with hyperactivity of the sympathetic nervous system (SNS) may be involved in the generation of acute hyperinflammation. We believe that sympathetic hyperactivity triggers a hyperresponsiveness of the immune system ("cytokine storm") with consecutive tissue damage. These reflectory neuroimmunological and inflammatory cascades constitute a general reaction principle of the organism under the leadership of the ANS and does not only occur in viral infections, although Covid-19 is a typical current example therefore. Within the overreaction several interdependent pathological positive feedback loops can be detected in which the SNS plays an important part. Consequently, there is a chance to regulate the hyperinflammation by influencing the SNS. This can be achieved by a stellate ganglion block (SGB) with local anesthetics, temporarily disrupting the pathological positive feedback loops. Thereafter, the complex neuroimmune system has the chance to reorganize itself. Previous clinical and experimental data have confirmed a favorable outcome in hyperinflammation (including pneumonia) after SGB (measurable e. g. by a reduction in proinflammatory cytokines).

Downregulation of HSPA12A underlies myotoxicity of local anesthetic agent bupivacaine through inhibiting PGC1α-mediated mitochondrial integrity

Local anesthetics (LAs) are widely used for intraoperative anesthesia and postoperative analgesia. However, LAs (e.g. Bupivacaine) can evoke myotoxicity that closely associated to mitochondrial damage. PGC1a is a mast co-factor for mitochondrial quality control. We have recently demonstrated that PGC1a can be activated by HSPA12A in hepatocytes, suggesting a possibility that HSPA12A protects from LAs myotoxicity through activating PGC1α-mediated mitochondrial integrity. Here, we reported that HSPA12A was downregulated during Bupivacaine-induced myotoxicity in skeletal muscles of mice in vivo and C2c12 myoblast cultures in vitro. Intriguingly, overexpression of HSPA12A attenuated the Bupivacaine-induced C2c12 cell death. We also noticed that the Bupivacaine-induced decrease of glucose consumption and ATP production was improved by HSPA12A overexpression. Moreover, overexpression of HSPA12A in C2c12 cells attenuated the Bupivacaine-induced decrease of mitochondrial contents and increase of mitochondrial fragmentation. The Bupivacaine-induced reduction of PGC1α expression and nuclear localization was markedly attenuated by HSPA12A overexpression. Importantly, pretreatment with a selective PGC1α inhibitor (SR-18292) abolished the protection of HSPA12A from Bupivacaine-induced death and mitochondrial loss in C2c12 cells. Altogether, the findings indicate that downregulation of HSPA12A underlies myotoxicity of Local anesthetic agent Bupivacaine through inhibiting PGC1α-mediated Mitochondrial Integrity. Thus, HSPA12A might represent a viable strategy for preventing myotoxicity of LAs.

Rectus sheath catheter analgesia versus standard care following major abdominal surgery: An observational study of 911 patients

BACKGROUND

It is unknown whether rectus sheath catheter (RSC) continuous infusion of local anaesthetic is superior to standard post-operative opiate analgesia following major abdominal surgery. Previous audit in our Trust had suggested RSC was very effective and reduced opiate analgesia use. We aimed to see if this was maintained as the technique became more widespread comparing clinical outcomes and post-operative opiate analgesia requirements between patients who had RSCs and those that did not following major abdominal surgery over a 32-month period.

METHODS

A retrospective observational study investigated patients who had major abdominal surgery at a single centre in the UK between January 2018 and August 2020. Placement of RSCs was at the discretion of the surgical team according to their own personal choice. All patients having the procedure in both an elective and non-elective setting have been included in this study, including patients requiring higher level care after emergency surgery. Clinical outcomes and post-operative opiate analgesia requirements (oral and intravenous) were analysed using multivariate logistic regression models adjusting for American Association of Anesthesiologists (ASA) grade and type of surgery (emergency vs elective and open vs laparoscopic).

RESULTS

There were 911 patients; 276/911 (30.3%) RSC and 635/911 (69.7%) non-RSC. Median age was 64 (52-74) years; 51.6% were male. In the adjusted models, RSC was associated with a reduced likelihood of serious complications (OR 0.49 (95% CI 0.33, 0.72); p < 0.001) and lower length of stay in ICU (OR 0.95 (95% CI 0.91, 0.99); p = 0.029). RSC was not associated with reduced post-operative opiate analgesia use. There were 3/276 (1.1%) adverse events following RSC placement during the period of data collection.

CONCLUSIONS

Clinical outcomes may be superior for patients following major abdominal surgery when RSCs are placed for post-operative analgesia but uncertainty remains. This paper highlights the difficulty with retrospective non-selected data in answering this question. High quality prospective randomised data are required to determine the effects on clinical outcomes and post-operative opiate analgesia requirements.

Safety of upper endoscopy in patients with active cocaine use

BACKGROUND

Cocaine is a synthetic alkaloid initially viewed as a useful local anesthetic, but which eventually fell out of favor given its high addiction potential. Its predominantly sympathetic effects raise concern for cardiovascular, respiratory, and central nervous system complications in patients undergoing procedures. Peri-procedural cocaine use, often detected via a positive urine toxicology test, has been mostly addressed in the surgical and obstetrical literature. However, there are no clear guidelines on how to effectively risk stratify patients found to be positive for cocaine in the pre-operative setting, often leading to costly procedure cancellations. Within the field of gastroenterology, there is no current data available regarding safety of performing esophagogastroduodenoscopy (EGD) in patients with recent cocaine use.

AIM

To compare the prevalence of EGD related complications between active (≤ 5 d) and remote (> 5 d) users of cocaine.

METHODS

In total, 48 patients who underwent an EGD at John H. Stroger, Jr. Hospital of Cook County from October 2016 to October 2018 were found to have a positive urine drug screen for cocaine (23 recent and 25 remote). Descriptive statistics were compiled for patient demographics. Statistical tests used to analyze patient characteristics, procedure details, and preprocedural adverse events included t-test, chi-square, Wilcoxon rank sum, and Fisher exact test.

RESULTS

Overall, 20 periprocedural events were recorded with no statistically significant difference in distribution between the two groups (12 active vs 8 remote, P = 0.09). Pre- and post-procedure hemodynamics demonstrated only a statistically, but not clinically significant drop in systolic blood pressure and increase in heart rate in the active user group, as well as drop in diastolic blood pressure and oxygen saturation in the remote group (P < 0.05). There were no significant differences in overall hemodynamics between both groups.

CONCLUSION

Our study found no significant difference in the rate of periprocedural adverse events during EGD in patients with recent vs remote use of cocaine. Interestingly, there were significantly more patients (30%) with active use of cocaine that required general anesthesia as compared to remote users (0%).

Effects of treatment with local anesthetics on RANKL expression in MG63 and PDL cells

Background/purpose

Local anesthesia (LA) application is a routine dental work in clinic. The aim of present study was to evaluate the extent of biologic effects of LA on periodontal ligaments (PDL) or bone cells (MG63).

Materials and methods

Local anesthetics (LAs) at different concentrations were added to PDL and MG 63 cells. The viability of the cells was analyzed using an MTT assay. The inflammatory markers, COX-2, IL-1, IL-6 and TNF-A, of PDL and MG63 cells treated with LAs were analyzed with a Western blot assay. The extract medium of the LA-treated PDL cells was added to the MG63 cells for subsequent culture and to examine the RANKL, ALP, and OPG expression. The data were statistically analyzed with p < 0.05 set as an indication of significance.

Results

The viability of the PDL and MG63 cells was less 50% at LAs concentrations above the 10 mM. At high LA concentrations, the PDL and MG63 cells treated with LAs became spherical in shape, or vesicles developed in the cytoplasm. The IL-1, IL-6, and TNF-A expression in the PDL groups showed no statistical differences between Septanest and Scandonest (p > 0.05). The RANKL expression in the MG63 cells increased as the Septanest and Scandonest concentrations were increased in the PDL extract medium (p < 0.05) after 48 h of culturing.

Conclusion

The LAs with adrenaline increased inflammation in the PDL and MG63 cells. The LA-treated PDL extract medium increased the RANKL expression in the MG63 cells.

Structural modeling of Nav1.5 pore domain in closed state

The voltage-dependent cardiac sodium channel plays a key role in cardiac excitability and conduction and it is the drug target of medically important. However, its atomic- resolution structure is still lack. Here, we report a modeled structure of Na_v1.5 pore domain in closed state. The structure was constructed by Rosetta-membrane homology modeling method based on the template of eukaryotic Na_v channel Na_vPaS and selected by energy and direct coupling analysis (DCA). Moreover, this structure was optimized through molecular dynamical simulation in the lipid membrane bilayer. Finally, to validate the constructed model, the binding energy and binding sites of closed-state local anesthetics (LAs) in the modeled structure were computed by the MM-GBSA method and the results are in agreement with experiments. The modeled structure of Na_v1.5 pore domain in closed state may be useful to explore molecular mechanism of a state-dependent drug binding and helpful for new drug development.

Anaphylactic reactions to local anesthetics in dental practice: a nationwide French retrospective study

OBJECTIVES

The primary aims of the present study were (1) to quantify and characterize anaphylactic type I reactions related to local anesthetics (LAs) drawing on the French Pharmacovigilance Database System over a 35-year period and (2) to focuse on reactions associated with dental procedures. The secondary aim was to infer an incidence rate in dental practice.

MATERIALS AND METHODS

All cases of anaphylactic reactions were selected using the algorithmic Standardized MeDRA Query "anaphylactic reaction." For each reaction, comprehensive data were collected, in particular the severity of symptoms, risk factors for anaphylaxis, and allergy testing. Imputability was assessed and a crude incidence rate in dental practice was estimated.

RESULTS

The first-line search identified 416 anaphylactic reactions, mostly of grade II (138) or III (240) severity. When restricted to dental practice, this number fell to 26 (grade I: 4; grade II: 10; grade III: 11; and grade IV: 1). Lidocaine was most often involved (81.49%) and mostly associated with anaphylactic reactions of grade II and III. Overall, 11 cases of fatal anaphylaxis were recorded, but no in dental practice. In dental practice, lidocaine was also the most frequently involved LA (57.69%).

CONCLUSIONS

All these findings highlight the very low incidence of type I-IgE-mediated reactions to LA, particularly in dental practice. The incidence rate of LA anaphylctic episodes in dental practice was estimated as 0.0261 anaphylactic episodes per million LA cartridges.

CLINICAL RELEVANCE

True anaphylactic reactions to LAs do occur and may justify a thorough investigation in dental practice.

Prolonged anesthesia and decreased toxicity of enantiomeric-excess bupivacaine loaded in ionic gradient liposomes

Bupivacaine is the most employed local anesthetic in surgical procedures, worldwide. Its systemic toxicity has directed the synthesis of the less toxic, S(-) enantiomer. This work describes a formulation of ionic gradient liposomes (IGL) containing _S75BVC, an enantiomeric excess mixture of 75% S(-) and 25% R(+) bupivacaine. IGL prepared with 250 mM (NH₄)₂SO₄ in the inner aqueous core of phosphatidylcholine and cholesterol (3:2 mol%) vesicles plus 0.5% _S75BVC showed average sizes of 312.5 ± 4.5 nm, low polydispersity (PDI < 0.18), negative zeta potentials (-14.2 ± 0.2 mV) and were stable for 360 days. The encapsulation efficiency achieved with IGL_S75BVC (%EE = 38.6%) was higher than with IGL prepared with racemic bupivacaine (IGL_RBVC, %EE = 28.3%). TEM images revealed spherical vesicles and µDSC analysis provided evidence on the interaction of the anesthetic with the lipid bilayer. Then, in vitro - release kinetics and cytotoxicity- and in vivo - toxic effects in Zebrafish and biochemical/histopathological analysis plus analgesia in Wistar rats - tests were performed. IGL_S75BVC exhibited negligible toxicity against Schwann cells and Zebrafish larvae, and it did not affect biochemical markers or the morphology of rat tissues (heart, brain, cerebellum, sciatic nerve). The in vitro release of _S75BVC from IGL was extended from 4 to 24 h, justifying the prolonged anesthetic effect measured in rats (~9 h). The advantages of IGL_S75BVC formulation over IGL_RBVC and plain bupivacaine formulations (prolonged anesthesia, preferential sensorial blockade, and no toxicity) confirm its potential for clinical use in surgical anesthesia.