Lipophilicity but not stereospecificity is a major determinant of local anaesthetic-induced cytotoxicity in human T-lymphoma cells

Local anesthetic tetracaine hydrochloride induces pyroptosis via caspase-3/gasdermin E in uveal melanoma

BACKGROUND

Evasion of pyroptosis is an effective survival strategy employed by cancer cells to evade immune cell attacks and drug-induced cytotoxicity. Exploring potent molecules capable of inducing pyroptosis in cancer cells has significant clinical implications for the control of cancer progression. Unexpectedly, we found that the local anesthetic tetracaine hydrochloride (TTC) induced pyroptosis, specifically in uveal melanoma but not in acral or cutaneous melanoma.

METHODS

We investigated the effects of TTC on various melanoma cell lines and performed transcriptome sequencing of TTC-treated uveal melanoma cells. The role of gasdermin E (GSDME), an executive protein responsible for pyroptosis, was explored using CRISPR-Cas13d knockdown, caspase-3 inhibitor treatment, and western blot analysis. Differential gene expression and pathway enrichment analyses were performed. Furthermore, we used tissue microarrays to assess GSDME expression levels in melanoma tissues from different anatomical sites.

RESULTS

TTC significantly induced pyroptosis specifically in uveal melanoma cells with high GSDME expression levels. TTC treatment could lead to GSDME cleavage by the caspase-3 in uveal melanoma C918 cells. GSDME knockdown or caspase-3 inhibition suppressed TTC-induced pyroptosis. Transcriptome analysis revealed differentially expressed genes enriched in signaling pathways related to pyroptosis, immunity, and cytokines.

CONCLUSIONS

This study showed that the local anesthetic TTC effectively induces pyroptosis in uveal melanoma through the caspase-3/GSDME pathway, highlighting its potential application in immunotherapy. Notably, the use of TTC has potential as an agent for inducing pyroptosis and as an adjuvant anticancer therapy in uveal melanoma.

Tetracaine hydrochloride induces macrophage pyroptosis through caspase‑1/11‑GSDMD signaling pathways

Tetracaine hydrochloride (TTC) is a long-lasting local anesthetic commonly used for topical anesthesia. Inappropriate dosage or allergic reactions to TTC can lead to local anesthetic toxicity. TTC exerts cytotoxic effects on certain cell types by inducing apoptosis and necrosis; however, the effects of TTC on macrophages are currently unclear. In the present study, the RAW 264.7 and BV2 cell lines, and murine peritoneal macrophages, were used to evaluate the cytotoxicity of TTC. The present study demonstrated that TTC caused a decrease in cell viability according to a Cell Counting Kit-8 assay, increased lactate dehydrogenase and IL-1β secretion according to ELISA, and induced morphological changes characteristic of pyroptosis according to western blotting. Moreover, TTC-induced macrophage pyroptosis was mediated by gasdermin (GSDM)D, and the cleavage of GSDMD was modulated by both caspase-1 and caspase-11. These results were experimentally validated using caspase-1 and caspase-11 inhibitors. Furthermore, it was observed that TTC and lipopolysaccharide (LPS) exerted similar effects on macrophages. However, the mechanism of induction of pyroptosis by TTC was different from that of LPS. The present study demonstrated that TTC alone could induce macrophage pyroptosis mediated by canonical and non-canonical inflammatory caspases. Therapies targeting pyroptosis may potentially provide a promising future strategy for the prevention and treatment of local anesthetic toxicity induced by TTC.

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.

Influence of Perioperative Anesthesia on Cancer Recurrence: from Basic Science to Clinical Practice

PURPOSEOF REVIEW

In this review, we will summarize the effects of these perioperative anesthetics and anesthetic interventions on the immune system and tumorigenesis as well as address the related clinical evidence on cancer-related mortality and recurrence.

RECENT FINDINGS

Cancer remains a leading cause of morbidity and mortality worldwide. For many solid tumors, surgery is one of the major therapies. Unfortunately, surgery promotes angiogenesis, shedding of circulating cancer cells, and suppresses immunity. Hence, the perioperative period has a close relationship with cancer metastases or recurrence. In the perioperative period, patients require multiple anesthetic management including anesthetics, anesthetic techniques, and body temperature control. Preclinical and retrospective studies have found that these anesthetic agents and interventions have complex effects on cancer outcomes. Therefore, well-planned, prospective, randomized controlled trials are required to explore the effects of different anesthetics and techniques on long-term outcomes after cancer surgery. Due to the conflicting effects of anesthetic management on cancer recurrence, further preclinical and clinical trials are required and beneficial to the development of systemic cancer therapies.

Comparative Metabolomics Study of the Impact of Articaine and Lidocaine on the Metabolism of SH-SY5Y Neuronal Cells

Articaine (ATC) and lidocaine (LDC) are the local anesthetics (LAs) currently most employed in dentistry. Cases of paresthesia, reported more frequently for ATC, have raised concerns about their potential neurotoxicity, calling for further investigation of their biological effects in neuronal cells. In this work, the impact of ATC and LDC on the metabolism of SH-SY5Y cells was investigated through 1H NMR metabolomics. For each LA, in vitro cultured cells were exposed to concentrations causing 10 and 50% reductions in cell viability, and their metabolic intracellular and extracellular profiles were characterized. Most effects were common to ATC and LDC, although with varying magnitudes. The metabolic variations elicited by the two LAs suggested (i) downregulation of glycolysis and of glucose-dependent pathways (e.g., one-carbon metabolism and hexosamine biosynthetic pathway), (ii) disturbance of branched chain amino acids (BCAA) catabolism, (iii) downregulation of TCA cycle anaplerotic fueling and activation of alternative energy producing pathways, (iv) interference with choline metabolism and (v) lipid droplet build-up. Interestingly, LDC had a greater impact on membrane phospholipid turnover, as suggested by higher phosphatidylcholine to phosphocholine conversion. Moreover, LDC elicited an increase in triglycerides, whereas cholesteryl esters accumulated in ATC-exposed cells, suggesting a different composition and handling of lipid droplets.

Comparison of in vitro and in vivo Toxicity of Bupivacaine in Musculoskeletal Applications

The recent societal debate on opioid use in treating postoperative pain has sparked the development of long-acting, opioid-free analgesic alternatives, often using the amino-amide local anesthetic bupivacaine as active pharmaceutical ingredient. A potential application is musculoskeletal surgeries, as these interventions rank amongst the most painful overall. Current literature showed that bupivacaine induced dose-dependent myo-, chondro-, and neurotoxicity, as well as delayed osteogenesis and disturbed wound healing in vitro. These observations did not translate to animal and clinical research, where toxic phenomena were seldom reported. An exception was bupivacaine-induced chondrotoxicity, which can mainly occur during continuous joint infusion. To decrease opioid consumption and provide sustained pain relief following musculoskeletal surgery, new strategies incorporating high concentrations of bupivacaine in drug delivery carriers are currently being developed. Local toxicity of these high concentrations is an area of further research. This review appraises relevant in vitro, animal and clinical studies on musculoskeletal local toxicity of bupivacaine.

Impact of epidural labor analgesia using sufentanil combined with low-concentration ropivacaine on maternal and neonatal outcomes: a retrospective cohort study

BACKGROUND

Whether epidural administered sufentanil combined with low-concentration ropivacaine affected labor progress as well as maternal and neonatal outcomes still remained unknown. The aim of this study was to assess the impact of epidural sufentanil plus ropivacaine on maternal and neonatal outcomes.

METHODS

This is a retrospective cohort study. Data of singleton full-term pregnancy women who received epidural labor analgesia for vaginal delivery from May 2018 to June 2020 were collected. Parturients were divided into two groups (the R group and the SR group) according to different medication regimens for epidural labor analgesia. The implementation of epidural analgesia during labor was performed with 0.167 % ropivacaine in the R group and 0.1 % ropivacaine in combination with 0.5 µg/ml sufentanil in the SR group. The primary outcome of our study included the duration of labor progress and the incidence of maternal fever, postpartum hemorrhage, fetal distress and neonatal Apgar scores less than 7 at 1 and 5 min. The secondary outcome included the incidence of episiotomy, instrumental delivery, caesarean section and grade III meconium-stained amniotic fluid.

RESULTS

There were a total 3778 deliveries during the study period, 1994 and 1784 parturients were included in the R group and in the SR group, respectively. The length of the first stage of labor was remarkably shorter in the R group in comparison to the SR group (548.0 ± 273.0 vs. 570.9 ± 273.0, P = 0.013). No significant difference was found in the incidence of maternal fever, postpartum hemorrhage, fetal distress and in the neonatal Apgar scores less than 7 at 1 and 5 min between two groups. Other Maternal outcomes were comparable in the R group and the SR group.

CONCLUSIONS

0.5 µg/ml sufentanil plus 0.1 % ropivacaine for epidural labor analgesia prolonged the duration of the first stage of labor, but did not have additional impact on maternal and neonatal outcomes compared with the sole 0.167 % ropivacaine.

TRIAL REGISTRATION

Clinical Research Information Service with registration number ChiCTR2100045162 . Registered 7 April 2021.

Viability and intracellular nitric oxide generation in the umbilical cord blood CD34+CD133- and CD34+CD133+ cell populations exposed to local anaesthetics

Local anesthetics (LAs) are capable of influencing cell viability in systemic immunity and may also modify metabolism of those present in umbilical cord blood (UCB) following obstetric neuraxial analgesia and anaesthesia. Data regarding UCB immature cells, important for the neonate and critical for putative UCB transplantations, are lacking. LAs are capable of stimulating intracellular nitric oxide (NO) in human neutrophils; no information is available concerning newly perpetuated cells and its potential association with viability. The study aimed at assessing the LAs influence on the cell viability and intracellular NO production by UCB CD34⁺CD133^– and CD34⁺ CD133⁺ cell populations. Mononuclear cells separated from UCB samples (n = 19) were incubated with bupivacaine (0.0005, 0.005, 1 mM), lidocaine (0.002, 0.02, 4 mM), and ropivacaine (0.0007, 0.007, 1.4 mM) for 4 h. Flow cytometry was applied for the assessment of cell viability and intracellular NO generation in CD34⁺CD133^– and CD34⁺CD133⁺ cell populations using annexinV/7-AAD and DAF-2DA stainings, respectively. CD34⁺CD133⁺ cells showed less pronounced late apoptosis and necrosis as compared to CD34⁺CD133-population. Intracellular NO generation was comparable between both cell populations studied. LAs neither influenced cell viability nor changed NO production in either population. LAs do not interfere with viability and intracellular NO generation in the UCB CD34⁺CD133^– and CD34⁺CD133⁺ cell populations.

Potential Impact of Local Anesthetics Inducing Granulocyte Arrest and Altering Immune Functions on Perioperative Outcome

Introduction

Local anesthetics (LAs) are frequently used during anesthesia; however, they may influence granulocyte function which in turn could modify immune responses in the perioperative period. Therefore, the aim of this study was to investigate the impact of clinically used doses of bupivacaine and lidocaine on granulocyte function with regard to migration, reactive oxygen species (ROS) production, neutrophil extracellular traps (NETosis) formation, and viability.

Methods

A total of 38 granulocyte-enriched samples from healthy subjects were obtained by whole blood lysis. Polymorphonuclear neutrophil (PMN) samples were incubated simultaneously with different concentrations of either bupivacaine (0.03–3.16 mmol/L) or lidocaine (0.007–14.21 mmol/L), or without drug (control). Live cell imaging was conducted in order to observe granulocyte chemotaxis, migration, ROS production, and NETosis. Flow cytometry was used to analyze viability and antigen expression.

Results

The track length (TL) of PMNs exposed to bupivacaine concentrations of 0.16 mmol/L and above significantly decreased compared to the control. Low concentrations of lidocaine were associated with slight but significant increases in TL, whereas this changed with concentrations above 1.4 mmol/L, showing a significant decrease in TL. PMN incubated with bupivacaine concentrations of 1.58 mmol/L and above or lidocaine concentrations of at least 3.6 mmol/L showed no migration or chemotaxis at all. Time to onset of maximal ROS production and time for half-maximal NETosis decreased in a dose-dependent manner for both substances. Equipotency in NETosis induction was reached by bupivacaine (1.1 mmol/L) at significantly lower concentrations than lidocaine (7.96 mmol/L). Cell viability and oxidative burst were unaffected by LAs.

Conclusion

Local anesthetics in clinically used doses ameliorate granulocyte defense mechanisms, thus indicating their potentially decisive effect during the perioperative period.

Anaesthetic modality and post-surgical oncological outcomes for paediatric tumours: is there a link?

INTRODUCTION

Children with solid organ tumours often present for curative surgery. Even with the best surgical technique, micrometastases can occur. Preclinical studies support the postulation that neuraxial anaesthesia maintains the body's immune and inflammatory milieu against metastasis. However, human retrospective adult studies showed varying results, and no study has been done in children. We aimed to find out if intraoperative epidural, perioperative opioid and volatile dose are associated with relapse-free survival (RFS) in children with solid organ tumours.

METHODS

This is a retrospective cohort study of 126 children from a tertiary paediatric unit who were diagnosed with solid organ tumours (neuroblastoma, hepatoblastoma or sarcoma) over a 16-year period. RFS, stratified by tumour subtypes, was estimated using the Kaplan-Meier method. Adjusted hazard ratios (aHRs) were obtained from multivariable Cox regression models after taking potential covariates into account.

RESULTS

Of 126 children with solid organ tumours (51.6% neuroblastoma, 34.9% sarcoma and 13.5% hepatoblastoma), 53.2% received combined general anaesthesia (GA)/epidural. A total of 21 (31.3%) and 20 (33.9%) patients relapsed during the study period in the combined GA/epidural group and the GA alone group, respectively. Patients with sarcoma receiving combined GA/epidural had a clinically meaningful lower risk of relapse compared to patients receiving GA alone (aHR 0.51, 95% confidence interval 0.14-1.79), although this was not statistically significant.

CONCLUSION

Our study demonstrated some clinically meaningful associations, especially in paediatric sarcoma patients. Overall, however, there was no statistically significant association between epidural use and an improved RFS.

Narrative review: the evidence for neurotoxicity of dental local anesthetics

Dental local anesthesia is performed daily on a global scale. Adverse effects are rare, but the topic of neurotoxicity of local anesthetics deserves to be explored, as publications can be controversial and confusing. Therefore, a need was felt to address and question the evidence for potential neurotoxicity of dental local anesthetics. This review aimed to assess the studies published on the neurotoxicity of dental local anesthetics. A Pubmed® search was conducted between January 2019 and August 2019. This revealed 2802 hits on the topic of neurotoxicity or cytotoxicity of the following anesthetics: lidocaine, prilocaine, mepivacaine, articaine, ropivacaine, and bupivacaine. Only 23 papers were deemed eligible for this review: 17 in vitro studies, 3 reviews and 3 audits of national inquiries. The heterogeneous literature on this topic showed that all dental local anesthetics are potentially neurotoxic in a concentration and/or exposure time fashion. There seems no consensus about what cell lines are to be used to investigate the neurotoxicity of local anesthetics, which makes the comparison between studies difficult and ambiguous. However, the bottom line is that all dental local anesthetics have a neurotoxic potential, but that there is no unanimity in the publications about which local anesthetic is the least or the most neurotoxic.

Perioperative regional anaesthesia and postoperative longer-term outcomes

Regional anaesthesia provides effective anaesthesia and analgesia in the perioperative setting. Central neuraxial blocks-that is, spinal and epidural blocks-are well established as an alternative or adjunct to general anaesthesia. Peripheral blocks may be used as part of multimodal anaesthesia/analgesia in perioperative practice, reducing the need for opioid analgesics and enhancing early recovery. Furthermore, regional anaesthesia has increased in popularity and may be done with improved ease and safety with the introduction of ultrasound-guided techniques. The effects of local anaesthetics and regional anaesthesia on long-term outcomes such as morbidity, mortality, the quality of recovery beyond the duration of analgesia, and whether it can expedite the resumption of activities of daily living are less clear. It has also been suggested that regional anaesthesia may impact the risk of metastasis after cancer surgery. This article provides an overview of current evidence around quality of recovery, risk for delirium, long-term effects, and possible impact on cancer disease progression associated with the clinical use of local and regional anaesthetic techniques. In summary, there is still a lack of robust data that regional anaesthesia has a clinical impact beyond its well-acknowledged beneficial effects of reducing pain, reduced opioid consumption, and improved quality of early recovery. Further high-quality prospective studies on long-term outcomes are warranted.

Inflammation and Epidural-Related Maternal Fever: Proposed Mechanisms

Intrapartum fever is associated with excessive maternal interventions as well as higher neonatal morbidity. Epidural-related maternal fever (ERMF) contributes to the development of intrapartum fever. The mechanism(s) for ERMF has remained elusive. Here, we consider how inflammatory mechanisms may be modulated by local anesthetic agents and their relevance to ERMF. We also critically reappraise the clinical data with regard to emerging concepts that explain how anesthetic drug-induced metabolic dysfunction, with or without activation of the inflammasome, might trigger the release of nonpathogenic, inflammatory molecules (danger-associated molecular patterns) likely to underlie ERMF.

Effects of Postoperative Pain Management on Immune Function After Laparoscopic Resection of Colorectal Cancer: A Randomized Study

There has been a rising interest in the possible association between perioperative opioid use and postoperative outcomes in cancer patients. Continuous surgical wound infiltration with local anesthetics is a nonopioid analgesic technique that can be used as a postoperative pain management alternative to opioid-based intravenous patient-controlled analgesia (IV PCA). The aim of this study was to compare the effects of an opioid-based analgesic regimen versus a local anesthetic wound infiltration-based analgesic regimen on immune modulation and short-term cancer recurrence or metastasis in patients undergoing laparoscopic resection of colorectal cancer.Sixty patients undergoing laparoscopic resection of colorectal cancer were randomly assigned to either the opioid group or the ON-Q group. For postoperative analgesia during the first 48 hours, the opioid group (n = 30) received fentanyl via IV PCA, whereas the ON-Q group (n = 30) received continuous wound infiltration of 0.5% ropivacaine with an ON-Q pump and tramadol via IV PCA. Pethidine for the opioid group and ketorolac or propacetamol for the ON-Q group were used as rescue analgesics. Anesthesia was induced and maintained with propofol and remifentanil. The primary outcome was postoperative immune function assessed by natural killer cell cytotoxicity (NKCC) and interleukin-2. Secondary outcomes were postoperative complications, cancer recurrence, or metastasis within 1 year after surgery, and postoperative inflammatory responses measured by white blood cell count, neutrophil percentage, and C-reactive protein. Immune function and inflammatory responses were measured before surgery and 24 and 48 hours after surgery.Fifty-nine patients completed the study. In the circumstance of similar pain control efficacy between the opioid group and the ON-Q group, postoperative NKCC and interleukin-2 levels did not differ between the 2 groups. The incidence of postoperative complications and recurrence or metastasis within 1 year after surgery was comparable between the groups. Postoperative inflammatory responses were also similar between the groups.When compared with ropivacaine wound infiltration-based analgesia, fentanyl-based analgesia did not further decrease NKCC or affect short-term cancer recurrence or metastasis. Thus, a fentanyl-based analgesic regimen and a ropivacaine wound infiltration-based analgesic regimen can both be used for postoperative pain management in laparoscopic resection of colorectal cancer.

Lipid emulsion attenuates apoptosis induced by a toxic dose of bupivacaine in H9c2 rat cardiomyoblast cells

The goal of this in vitro study was to investigate the effect of lipid emulsion on apoptosis induced by a toxic dose of bupivacaine (BPV) in H9c2 rat cardiomyoblast cell lines. The effect of lipid emulsion on the decreased cell viability and count induced by BPV or mepivacaine (MPV) in the H9c2 cells was assessed using an 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyl tetrazolium bromide assay or a cell count assay. The effect of BPV or lipid emulsion combined with BPV on cleaved caspase 3, caspase 8, and Bax in H9c2 cells was investigated using Western blotting. A terminal deoxynucleotidyl transferase dUTP2'-deoxyuridine 5'-triphosphate nick end-labeling (TUNEL) assay was performed to detect apoptosis of H9c2 cells treated with BPV alone or lipid emulsion combined with BPV. The magnitude of lipid emulsion-mediated attenuation of decreased cell viability induced by BPV was higher than that of lipid emulsion-mediated attenuation of decreased cell viability induced by MPV. Lipid emulsion attenuated the increases in cleaved caspase 3, caspase 8 and Bax induced by BPV. Lipid emulsion attenuated the increases in TUNEL-positive cells induced by BPV. These results suggest that lipid emulsion attenuates a toxic dose of BPV-induced apoptosis via inhibition of the extrinsic and intrinsic apoptotic pathways. The protective effect of lipid emulsion may be partially associated with the relatively high lipid solubility of BPV.

[Interaction of anesthetics and analgesics with tumor cells]

The results of preclinical and clinical studies indicate that the perioperative period is a vulnerable period for cancer progression and metastasis. The risk of cancer cell dissemination is enhanced by the combination of surgical manipulation and perioperative immunosuppression. Whether the oncological outcome of cancer patients can be influenced by the choice of anesthetic techniques is still a matter of debate. This review summarizes the molecular characteristics of cancer and interaction of anesthetic and analgesic drugs with cancer cells.

The potential benefits of the use of regional anesthesia in cancer patients

Cancer is a leading cause of morbidity and mortality worldwide. In light of demographic changes among other factors, it is anticipated this trend will continue. Surgical resection is the primary method of treating solid tumours. Unfortunately, even with the use of adjunct therapies, metastatic disease is a leading cause of death in people with cancer. Recent evidence suggests choice of anesthetic technique may influence cancer outcome. This review considers the latest evidence regarding local and regional anesthesia in the context of cancer biology. There is a focus on the indirect and direct mechanisms involved. An integrated approach is used such that diverse areas of research are explored; ranging from epigenetics to cell death pathways. With a better understanding of how regional anesthesia and/or local anesthetics interact with cancer cells, these techniques can be trialed and evaluated to ascertain potential clinical benefits in cancer patients. Thus far, there is insufficient evidence to warrant a change in clinical practice.

Are we causing the recurrence-impact of perioperative period on long-term cancer prognosis: Review of current evidence and practice

Newer developments in the field of chemotherapeutic drug regimes, radiotherapy, and surgical techniques have improved the prognosis of cancer patients tremendously. Today increasing numbers of patients with aggressive disease are posted for surgical resection. The advances in reconstructive flap surgery offer the patient a near normal dignified postresection life. Hence, the expectations from the patients are also on the rise. Anesthetic challenges known in oncosurgery are that of difficult airway, maintenance of hemodynamics and temperature during long surgical hours, pain management, and postoperative intensive care management. But, recently acquired data raised the possibility of the anesthetic technique and conduct of perioperative period as a possible contributory factor in the growth and possible recurrence of the primary tumor. The foundation of the concept is somewhat fragile and not supported by conclusive evidence. In fact, like any other controversial topic in medicine, contradictory reports of the favorable effects of anesthetic technique and medications are plenty in the literature. This is the basis of our article where we have analyzed the current evidence available in the literature and how these and the forthcoming large scale studies may revolutionize the practice of oncoanesthesia.

[Update on the pharmacology and effects of local anesthetics]

Local anesthetics (LA) are broadly used in all disciplines and it could be considered that relatively little is reflected on the mechanisms of action of this old substance group. However, several molecular mechanisms of LAs mediating wanted and unwanted effects remain to be explored. Furthermore, the number of indications for application of LAs seems to be expanding. The local anesthetic effect of LAs is primarily mediated by a potent inhibition of voltage-gated sodium channels. However, this effect is due to much more than the interaction of LAs with one single molecule. Most recent studies indicated that the development of selective local anesthetics might be possible and LAs also interact with several other membrane molecules. Although the relevance of these effects is still unclear, they might play a role in systemic analgesia, tissue protection and anti-inflammatory effects of LA. The therapeutic index of systemically applied LA is very narrow. Systemic application is formally not permitted because the impending systemic toxicity is still a life-threatening complication. Although the cardiac and central nervous toxicity at least partly result from an unselective block of neuronal and cardiac sodium channels, preclinical studies suggest the involvement of several mechanisms. A local LA toxicity is less clinically impressive; however, all LAs induce a significant tissue toxicity for which the underlying mechanisms have been partly identified. This review reports on recent findings on mechanisms and on the clinical relevance of some LA-induced effects which are of relevance for anesthesiological activities.

Does regional anaesthesia and analgesia or opioid analgesia influence recurrence after primary cancer surgery? An update of available evidence

Cancer continues to be a key cause of morbidity and mortality worldwide and its overall incidence continues to increase. Anaesthetists are increasingly faced with the challenge of managing cancer patients, for surgical resection to debulk or excise the primary tumour, or for surgical emergencies in patients on chemotherapy or for the analgesic management of disease- or treatment-related chronic pain. Metastatic recurrence is a concern. Surgery and a number of perioperative factors are suspected to accelerate tumour growth and potentially increase the risk of metastatic recurrence. Retrospective analyses have suggested an association between anaesthetic technique and cancer outcomes, and anaesthetists have sought to ameliorate the consequences of surgical trauma and minimise the impact of anaesthetic interventions. Just how anaesthesia and analgesia impact cancer recurrence and consequent survival is very topical, as understanding the potential mechanisms and interactions has an impact on the anaesthetist's ability to contribute to the successful outcome of oncological interventions. The outcome of ongoing, prospective, randomized trials are awaited with interest.

Levobupivacaine vs. bupivacaine for third molar surgery: quality of anaesthesia, postoperative analgesia and local vascular effects

OBJECTIVES

The main purpose of this prospective, double-blind, randomized study was to evaluate anaesthetic parameters, postoperative analgesia and vasoactive properties of levobupivacaine and bupivacaine for lower third molar surgery.

MATERIAL AND METHODS

Sixty patients (ASA I) were scheduled for lower third molar surgery under inferior alveolar nerve block, lingual nerve block and buccal nerve block (mandibular nerve blocks) obtained with 3 ml of 0.5 % levobupivacaine and 3 ml of 0.5 % bupivacaine. Success rate, onset and duration of three nerve bocks were evaluated by electrical pulp testing, pinprick testing and signs of soft tissue anaesthesia (patient-reported numbness). Intensity of intraoperative anaesthesia and postoperative analgesia were measured with visual analogue scale (VAS) and numeric rating scale (NRS). The time of first postoperative pain reported and analgesic consumption were also recorded. The laser Doppler flowmetry was used for the measurement of the first premolar pulpal blood flow.

RESULTS

There were no differences between levobupivacaine and bupivacaine regarding the success rate, onset and duration of mandibular nerve blocks as well as intensity of postoperative analgesia and analgesic consumption. Intensity of intraoperative anaesthesia and duration of postoperative analgesia were significantly higher in the levobupivacaine than in the bupivacaine group. Both anaesthetics showed similar biphasic vasoactive effect.

CONCLUSIONS

Levobupivacaine 0.5 % achieved superiority over bupivacaine 0.5 % in the intensity of intraoperative anaesthesia and duration of postoperative analgesia for lower third molar surgery under the mandibular nerve blocks.

CLINICAL RELEVANCE

It seems that the plain levobupivacaine (0.5 %) could be an effective alternative to plain bupivacaine (0.5 %) in those dental procedures which require profound bone and soft tissue anaesthesia.

Can anaesthetic and analgesic techniques affect cancer recurrence or metastasis?

Cancer is a leading cause of morbidity and mortality worldwide and the ratio of incidence is increasing. Mortality usually results from recurrence or metastases. Surgical removal of the primary tumour is the mainstay of treatment, but this is associated with inadvertent dispersal of neoplastic cells into the blood and lymphatic systems. The fate of the dispersed cells depends on the balance of perioperative factors promoting tumour survival and growth (including surgery per se, many anaesthetics per se, acute postoperative pain, and opioid analgesics) together with the perioperative immune status of the patient. Available evidence from experimental cell culture and live animal data on these factors are summarized, together with clinical evidence from retrospective studies. Taken together, current data are sufficient only to generate a hypothesis that an anaesthetic technique during primary cancer surgery could affect recurrence or metastases, but a causal link can only be proved by prospective, randomized, clinical trials. Many are ongoing, but definitive results might not emerge for a further 5 yr or longer. Meanwhile, there is no hard evidence to support altering anaesthetic technique in cancer patients, pending the outcome of the ongoing clinical trials.