Local anaesthetic-induced myotoxicity in regional anaesthesia: a systematic review and empirical analysis

Diffusion doping of analgesics into UHMWPE for prophylactic pain management

Pain management after total joint arthroplasty is often addressed by systemic delivery of opioids. Local delivery of non-opioid analgesic drugs directly in the joint space from the UHMWPE component of the prosthesis would be highly beneficial to increase the efficacy of the drugs, decreasing the overall side effects and the risk of opioid addiction. It has been shown that effective concentrations of local analgesics can be achieved by eluting from analgesic-blended UHMWPE; however, this approach is limited by the decrease in mechanical properties resulting from the extent of phase separation of the blended drugs from the polymeric matrix. Here we hypothesized that mechanical properties could be maintained by incorporating analgesics into solid form UHMWPE by diffusion as an alternative method. Lidocaine or bupivacaine were diffused in solid form UHMWPE with or without radiation crosslinking. The loaded drug content, the spatial distribution of the drugs and their chemical stability after doping were characterized by FTIR and NMR spectroscopy, respectively. Drug release kinetics, tensile mechanical properties and wear rates were assessed. The results showed that diffusion doping could be used as a promising method to obtain a therapeutic implant material without compromising its mechanical and structural integrity.

Use of corticosteroids for adult chronic pain interventions: sympathetic and peripheral nerve blocks, trigger point injections - guidelines from the American Society of Regional Anesthesia and Pain Medicine, the American Academy of Pain Medicine, the American Society of Interventional Pain Physicians, the International Pain and Spine Intervention Society, and the North American Spine Society

BACKGROUND

There is potential for adverse events from corticosteroid injections, including increase in blood glucose, decrease in bone mineral density and suppression of the hypothalamic-pituitary axis. Published studies note that doses lower than those commonly injected provide similar benefit.

METHODS

Development of the practice guideline was approved by the Board of Directors of American Society of Regional Anesthesia and Pain Medicine with several other societies agreeing to participate. The scope of guidelines was agreed on to include safety of the injection technique (landmark-guided, ultrasound or radiology-aided injections); effect of the addition of the corticosteroid on the efficacy of the injectate (local anesthetic or saline); and adverse events related to the injection. Based on preliminary discussions, it was decided to structure the topics into three separate guidelines as follows: (1) sympathetic, peripheral nerve blocks and trigger point injections; (2) joints; and (3) neuraxial, facet, sacroiliac joints and related topics (vaccine and anticoagulants). Experts were assigned topics to perform a comprehensive review of the literature and to draft statements and recommendations, which were refined and voted for consensus (≥75% agreement) using a modified Delphi process. The United States Preventive Services Task Force grading of evidence and strength of recommendation was followed.

RESULTS

This guideline deals with the use and safety of corticosteroid injections for sympathetic, peripheral nerve blocks and trigger point injections for adult chronic pain conditions. All the statements and recommendations were approved by all participants after four rounds of discussion. The Practice Guidelines Committees and Board of Directors of the participating societies also approved all the statements and recommendations. The safety of some procedures, including stellate blocks, lower extremity peripheral nerve blocks and some sites of trigger point injections, is improved by imaging guidance. The addition of non-particulate corticosteroid to the local anesthetic is beneficial in cluster headaches but not in other types of headaches. Corticosteroid may provide additional benefit in transverse abdominal plane blocks and ilioinguinal/iliohypogastric nerve blocks in postherniorrhaphy pain but there is no evidence for pudendal nerve blocks. There is minimal benefit for the use of corticosteroids in trigger point injections.

CONCLUSIONS

In this practice guideline, we provided recommendations on the use of corticosteroids in sympathetic blocks, peripheral nerve blocks, and trigger point injections to assist clinicians in making informed decisions.

The impact of the transversus abdominis plane block (TAP) on stress response measured through the complete blood- derived inflammatory markers

This study aims to evaluate the effect of the transversus abdominis plane (TAP) block on the blood cells and the inflammatory markers neutrophil- to- lymphocyte ratio (NLR), platelet- to- lymphocyte ratio (PLR), and systemic immune- inflammation index (SII) after the laparoscopic ovariectomy (LapOV) in dogs. 72 healthy bitches undergoing LapOV were randomly allocated to the no- TAP group of dogs under inhaled anesthesia (IA), the TAP- S group (IA and TAP with saline), and the TAP- B group (IA and TAP with bupivacaine). The NLR, PLR, and SII were calculated 1 h before ovariectomy (T0) and at 2-3 h (T1), 6-8 h (T2), and 20-24 h (T3) post- surgery. The number of dogs requiring postoperative analgesic rescue with buprenorphine and the doses administered in each group were recorded. Significant changes were observed in all groups' postoperative NLR, PLR, and SII over time. Between groups, no differences were observed in any of the ratios at any control point (NLR at T0-T3: p = 0.17, 0.36, 0.80, and 0.95; PLR at T0-T3: p = 0.70, 0.62, 0.21, 0.87; SII at T0-T3: p = 0.29, 0.65, 0.09, and 0.34). A significantly lower number of dogs required analgesic rescue in the TAP-B group (p = 0.0001) and a lower number of doses were administered (p = 0.001). There is no difference in the inflammatory response measured through the complete blood- derived inflammatory markers after the LapOV in dogs when the postoperative pain is managed entirely with opioids or with the TAP block with bupivacaine. The hydrodissection associated with the TAP block technique does not increase the inflammatory response.

Pain relief after major ankle and hindfoot surgery with repetitive peripheral nerve blocks: A feasibility study

BACKGROUND

Major ankle and hindfoot surgery (e.g., ankle, triple and subtalar arthrodesis) typically causes severe postoperative pain, especially the first two postoperative days. Current modalities of postoperative analgesic treatment often include continuous peripheral nerve blocks of the saphenous and sciatic nerves via catheters in order to extend the duration of pain- and opioid-free nerve blockade to 48 h. Unfortunately, the 48 h-efficacy of continuous infusion via a catheter is reduced by a high displacement rate. We hypothesised that one-time repetition of the single injection peripheral nerve blocks would provide effective analgesia with a low opioid consumption the first 48 postoperative hours.

METHODS

Eleven subjects preoperatively received a popliteal sciatic and a saphenous single injection nerve block with a protracted local anaesthetic mixture. Surgery was performed under general anaesthesia. The one-time repetition of the single injection nerve block was carried out approximately 24 h after the primary nerve block. The main outcomes were pain and cumulative opioid consumption during the first 48 postoperative hours.

RESULTS

Nine of the 11 (82%) patients had effective analgesia without opioids during the first 48 postoperative hours. Two patients each required a single dose of 7.5 mg of oral morphine equivalents after 43 h.

CONCLUSION

One-time repetition of single injection saphenous and sciatic nerve blocks consistently provided effective analgesia practically without opioids for 48 h after major elective ankle and hindfoot surgery.

Outcome comparison of femoral nerve block and adductor canal block during anterior cruciate ligament reconstruction: adductor canal block may cause an unexpected decrease in knee flexor strength at 6 months postoperatively

INTRODUCTION

Peripheral nerve blocks are frequently used in anterior cruciate ligament (ACL) reconstruction. While femoral nerve block (FNB) has been associated with knee extensor strength reduction in the early postoperative period, no consistent view of knee extensor strength several months after ACL reconstruction exists. This study aimed to compare the impact of intraoperative FNB and adductor canal block (ACB) during ACL reconstruction on knee extensor strength at 3 and 6 months postoperatively.

MATERIALS AND METHODS

This retrospective study included 108 patients divided into FNB (70 patients) and ACB (38 patients) groups based on their postoperative pain management methods. Knee joint extensor and flexor strength were measured at 3 and 6 months postoperatively, using BIODEX at angular velocities of 60°/s and 180°/s. From these results, peak torque, limb symmetry index (LSI), peak knee extensor torque (time to peak torque and angle of peak torque), hamstrings-to-quadriceps (HQ) ratio, and amount of work were computed for two-group comparison.

RESULTS

There were no statistically significant differences in peak torque, LSI of knee extensor strength, HQ ratio, and amount of work between the two groups. However, maximum knee extension torque at 60°/s occurred significantly later in the FNB than in the ACB group at 3 months postoperatively. Additionally, the LSI of the knee flexor at 6 months postoperatively was significantly lower in the ACB group.

CONCLUSIONS

In ACL reconstruction, FNB may delay the time to peak torque for knee extension at 3 months postoperatively, which is likely to improve over the treatment course. In contrast, ACB may result in unexpected loss of knee flexor strength at 6 months postoperatively and should be considered with caution.

LEVEL OF EVIDENCE

Level III.

Management of perioperative pain after TKA

Postoperative pain is the prime obstacle to recovery of motion and return to activity after total knee arthroplasty (TKA). Combating pain is a key point in enhanced recovery after surgery (ERAS) protocols. Outcome depends on the efficacy of pain relief, making it a major issue. The pain originates locally in the knee and also remotely via neural pathways. Regression can be slow, over several months. Pain may sometimes be definitive, to a varying degree. Pain should be managed at each step of ERAS, from the preoperative period to the last follow-up consultation, and most especially during the perioperative phase. Pain needs to be anticipated and limited for as long as necessary. The impact of analgesics should be enhanced by means of potentiators. Some are administered by general route, sometimes preoperatively; others are applied locally, directly in the surgical site by local injection, or close to the nerves, to reduce painful stimuli. The two main principles of pain management are preventive analgesia and multimodal analgesia associating various molecules and routes.

Role of adjuvants in regional anesthesia: A systematic review

The combination of drugs and routes of administration produces a synergistic effect, and one of the most important components of multimodal analgesic strategies are, therefore, nerve blocks for pain management. The effect of a local anaesthetic can be prolonged by administering an adjuvant. In this systematic review, we included studies on adjuvants associated with local anaesthetics in peripheral nerve blocks published in the last 5 years in order to evaluate their effectiveness. The results were reported according to the PRISMA guidelines. The 79 studies selected using our criteria showed a clear prevalence of dexamethasone (n=24) and dexmedetomidine (n=33) over other adjuvants. Different meta-analyses comparing adjuvants suggest that dexamethasone administered perineurally achieves superior blockade with fewer side effects than dexmedetomidine. Based on the studies reviewed, we found moderate evidence to recommend the use of dexamethasone as an adjuvant to peripheral regional anaesthesia in surgeries that can cause moderate to severe pain.

Pain Specialist Management of Sexual Pain-II: Interventional

INTRODUCTION

Treatment of female sexual pain often requires the use of diverse modalities crossing multiple medical disciplines. Interventional procedures are important in the diagnosis and treatment of female sexual pain. Pain specialists and other medical specialties can provide these capabilities.

OBJECTIVES

To provide a current summary of the procedures used in the diagnosis and treatment of female sexual pain.

METHODS

The internet, PubMed, and the Cochrane Library were searched for relevant articles on female sexual pain within the clinical purview and scope of the practice of pain management.

RESULTS

A thorough review of the literature was conducted to include basic science studies, clinical trials, systematic reviews, consensus statements, and case reports. An effort was made to also include a sampling of information on real-world patient self-directed therapies. Descriptions of interventional procedures for the diagnosis and treatment of sexual pain were made and clinical studies reviewed. The evidence for the use of various interventional treatment strategies for sexual pain was assessed.

CONCLUSIONS

The process of care for female sexual pain employs an interdisciplinary biopsychosocial model that includes a role for interventional procedures commonly performed by pain management specialists. These specialists are a resource of knowledge, skills, and abilities that can be used to improve the care of women with chronic sexual pain.

Cytotoxicity of Local Anesthetics on Bone, Joint, and Muscle Tissues: A Narrative Review of the Current Literature

Background

Local anesthetics are commonly used in surgical procedures to control pain in patients. Whilst the cardiotoxicity and neurotoxicity of local anesthetics have received much attention, the cytotoxicity they exert against bone, joint, and muscle tissues has yet to be well recognized.

Objective

This review aimed to raise awareness regarding how local anesthetics may cause tissue damage and provide a deeper understanding of the mechanisms of local anesthetic-induced cytotoxicity. We summarized the latest progress on the cytotoxicity of local anesthetics and the underlying mechanisms and discussed potential strategies to reduce it.

Findings

We found that the toxic effects of local anesthetics on bone, joint, and muscle tissues were time- and concentration-dependent in vitro. Local anesthetics induced apoptosis, necrosis, and autophagy through specific cellular pathways. Altogether, this review indicates that toxicity of local anesthetics may be avoided by rationally selecting the appropriate anesthetic, limiting the total amount, and determining the lowest effective concentration and duration.

Safety of tongue base procedures for sleep apnoea in adults: A systematic review and metanalysis from the YO-IFOS study group

OBJECTIVE

Tongue base and hypopharynx are the major sites of obstruction in OSA patients with failed palatal surgery. In recent years, several minimally invasive procedures have been developed to address tongue base obstruction. However, the research focus has consistently been on the effectiveness of surgery in reducing obstructive sleep apnoea rather than on postoperative complications. In this systematic review and metanalysis we aim to review the complication rate of minimally invasive base of tongue procedures for OSAS in adults.

DATA SOURCES

PubMed (Medline), the Cochrane Library, EMBASE, Scopus, SciELO and Trip Database.

REVIEW METHODS

Data sources were checked by three authors of the YO-IFOS sleep apnoea study group. Three authors extracted the data. Main outcome was expressed as the complication rate and 95% confidence interval for each surgical technique.

RESULTS

20 studies (542 patients) met the inclusion criteria. The mean complication rate is 12.79%; 4.65% for minor complications, 6.42% if they are moderate, and 1.77% if severe. The most reported complication overall is infection, in 1.95% of cases, followed by transient swallowing disorder, occurring in 1.30% of the total sample.

CONCLUSION

The heterogeneity amongst the included studies prevents us from obtaining solid conclusions. The available evidence suggests that minimally invasive base of tongue procedures may present a wide spectrum of complication rates, ranging from 4.4% in tongue base radiofrequency to up to 42.42% in tongue base ablation.

The Skeletal Muscle Microbiopsy Method in Exercise and Sports Science Research: A Narrative and Methodological Review

BACKGROUND

The skeletal muscle microbiopsy protocol was introduced to the Exercise and Sports Science (ESS) research field in 1999 and has been used as a protocol to directly examine muscular structural and biochemical changes. There is much variation in the reporting of the microbiopsy protocol and its related pre-and post-procedure for participant care and sample collection. The purpose of this narrative and methodological review is to compare the microbiopsy to the traditional Bergström protocol used in the ESS field, identify and summarize all related microbiopsy protocols used in previous ESS studies and determine the most frequently used microbiopsy protocols aspects and associated pre- and post-biopsy procedures; METHODS: A review of literature up to January, 2022 was used following the PRISMA and Cochrane Methodological Review Guide to determine frequently used methods that may facilitate optimal and potential recommendations for muscle microbiopsy needle gauge (G), concentration or dose (% or mL) and administration of local anesthetic, co-axial/cannula introducer gauge (G), muscle depth (cm), muscle sample size collected (mg), passes to collect samples, time points of muscle sampling, and promotion of participant compliance and minimization of adverse events; RESULTS: 85 articles were selected based on the inclusionary requirements related to the ESS field or methodological considerations. The most frequently reported aspects in previous research to suggest the location of the vastus lateralis is the midpoint between the patella and the greater trochanter of the femur or 1/3 or 2/3 the distance from the patella to anterior superior iliac spine, 14 G biopsy needle, subcutaneous injected lidocaine administration (2 mL; 1%), 13 G co-axial/cannula, 1-2 cm muscle depth, 10-20 mg of muscle sample, ~3-time points, 2-3 passes; DISCUSSION: There is much variation in the reporting of the microbiopsy protocol and its related pre-and post-biopsy procedures. Standardization in reporting may promote recommendations to optimize data integrity, participant safety, participant adherence to the study design, and increase reproducibility. Recommendations are made for the microbiopsy procedure based on frequently reported characteristics.

Effects of hydrodissection on anesthesia characteristics in ultrasound guided infraclavicular brachial plexus blockade

BACKGROUND

The development of ultrasonography technology and its widespread application have increased peripheral nerve block applications, especially in limb surgeries, since it reduces complication rates and increases success rates in peripheral nerve block applications. However, even experienced physicians need to direct a large number of needles and injections for adequate local anesthetic spread, which can cause accidental vascular puncture and local anesthetic systemic toxicity. Such complications can be prevented by hydrodissection and a safer and successful anesthesia can be provided to patients in this study, it was aimed to investigate the effects of hydrodissection on anesthesia characteristics in the infraclavicular brachial plexus blockade.

MATERIALS AND METHODS

Ninety patients were included in our study after approval by the Ethics Committee. These patients were randomly divided into 2 groups (Group I: Infraclavicular brachial plexus blockade with normal method and Group II: infraclavicular brachial plexus blockade with hydrodissection). After obtaining patient consent, monitoring and vascular access were provided. Group I patients were mixed with 30 mL of local anesthetic mixture (15 mL of distilled water and 15 mL of 0.5% bupivacaine), and Group II patients were treated with 15 mL of distilled water by hydrodissection and 15 mL of 0.5% bupivacaine anesthesia resident. Block characteristics were evaluated and recorded every 5 minutes for the first 30 minutes by a blinded observer. The sensory block score was 7, the total score was 14 or above, and the block was considered successful, and the patient was ready for surgery. Postoperative block removal times, analgesia, and complications were evaluated and recorded.

RESULTS

A significant difference was found between the sensory and motor block onset times and postoperative VAS scores between the normal and hydrodissection groups (P < .05). There were no significant differences in terms of block application times, postoperative block removal times, and complications between the groups.

CONCLUSION

In this study, it has been shown that hydrodissection in peripheral nerve blocks does not lag in terms of block success and characteristics compared to normal methods, whereas anesthetists with less experience in peripheral nerve block experience obtain safer and more successful results in practice.

Effects of Aging on Basement Membrane of Tibialis Anterior Muscle During Recovery Following Muscle Injury in Rats

We investigated the effect of aging on the basement membrane (BM) during postinjury muscle recovery. Using a rat model, we found that aging delayed muscle fiber and BM recovery. In addition, expression of BM-related factors peaked 7 days after muscle injury among both young and older rats. Peak expression of collagen IV synthetic factors decreased with age, whereas expression of the degradative factor was unaffected by age. These results suggest that age-related delays in postinjury muscle fiber and BM recovery may be related to the suppression of collagen IV synthetic factors.

Effect of Fentanyl as an Adjuvant to Brachial Plexus Block for Upper Extremity Surgeries: A Systematic Review and Meta-Analysis of RCTs

Objective

To assess if the addition of fentanyl to brachial plexus block has an impact on anesthetic outcomes and complication rates in patients undergoing upper extremity surgeries.

Methods

We explore the PubMed, Embase, ScienceDirect, CENTRAL, and Google Scholar databases for all randomized controlled trials (RCTs) comparing adjuvant fentanyl with placebo/no drug for patients undergoing upper extremity surgery under brachial plexus block. Outcomes assessed were onset, duration of sensory and motor anesthesia, complications, and postoperative analgesia scores. Meta-analysis was conducted utilizing a random-effects model. The risk of bias was assessed using the Cochrane Collaboration's risk of bias assessment tool 2. Certainty of evidence was assessed using GRADE. Subgroup analysis was conducted depending upon the approach of brachial plexus block and type of local anesthetic.

Results

Twelve RCTs with 660 patients were included. Addition of fentanyl had no effect on onset of sensory anesthesia (11 studies; MD: 0.48; 95% CI: -1.81, 0.85; I 2 = 96%; p=0.48) but significantly shortened onset of motor anesthesia (8 studies; MD: -2.36; 95% CI: -3.99, -0.74; I 2 = 96%; p=0.48). Duration of sensory anesthesia (9 studies; MD: 82.81; 95% CI: 41.81, 123.81; I 2 = 99%; p < 0.0001) and motor anesthesia (7 studies; MD: 93.41; 95% CI: 42.35, 144.46; I 2 = 99%; p=0.0003) was significantly increased with addition of fentanyl. The certainty of evidence-based on GRADE was deemed to be moderate for both onset and duration of anesthesia. The incidence of overall complications (nausea/vomiting and pruritis) was significantly higher in the fentanyl group (7 studies; OR: 2.14; 95% CI: 1.04, 4.40; I 2 = 8%; p=0.04) but with low certainty of evidence.

Conclusions

Adjuvant fentanyl with brachial plexus block improves the onset of motor anesthesia but not sensory anesthesia. The duration of both sensory and motor anesthesia is significantly prolonged with fentanyl by around 83-93 minutes. However, clinicians should be aware that complications such as nausea/vomiting and pruritis are increased twofold with the addition of the drug. Current evidence is limited risk of bias in the RCTs and high heterogeneity in the meta-analyses.

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.

Ropivacaine instillation through subgaleal drain: A novel approach for acute post-craniotomy pain

Background and Aims:

Post-craniotomy pain has often been overlooked and undertreated. Various classes of analgesic drugs have been used, not without limitations. Therefore, we planned to study the novel technique of wound instillation of ropivacaine through the surgical drain in patients undergoing supratentorial craniotomy to study its effect on post-craniotomy pain, analgesic requirement in the post-operative period along with the recovery profile of the patient and the side effects.

Methods:

This prospective, randomised, placebo-controlled, double-blinded study enroled 50 patients of either gender, scheduled to undergo elective craniotomy, under general anaesthesia. They were randomly divided into two groups and received either 12 ml of 0.25% ropivacaine (group R) or 12 ml of normal saline (group NS), through the subgaleal drain, after the closure of the dura. Pain scores were assessed at 1, 2, 4, 8 and 24 hours post-operatively. Student’s t-test was used for comparison of continuous variables and the Chi-square test or Fisher’s exact test was used for comparing the nominal categorical data.

Results:

The visual analogue scale score was higher in group NS than in group R, and the difference was statistically significant (P = 0.012, 0.016, and 0.005 at 0, 1, and 2 post-operative hours, respectively). The difference in the mean emergence time in the two groups was 1.12 minutes (P = 0.024).

Conclusion:

Single-time wound instillation of ropivacaine (12 ml of 0.25%) through surgical (subgaleal) drain during wound closure is an effective and simple technique for reducing post-operative pain and analgesic consumption and early emergence in neurosurgical patients undergoing supratentorial craniotomy.

Learning from natural design for local anesthetic delivery

There is a sizeable but unfilled need for drug delivery systems that prolong the duration of action and reduce the systemic toxicity of local anesthetics. Inspired by the interactions of anesthetics with their natural binding sites on sodium channels, Ji et al. designed self-assembled nanostructures that achieve specific delivery and sustained release of anesthetics.

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.

Paraspinal desmoid fibromatosis after lumbar epidural analgesia

A 14-year-old girl with cerebral palsy presented for bilateral lower limb surgery for spasticity. A lumbar epidural catheter was sited under general anaesthesia on the third attempt and used intra-operatively with good effect. A local anaesthetic infusion was used for postoperative analgesia but was noted to be leaking under the dressing with a patchy, unilateral block. The catheter was therefore removed on the second postoperative day. Following discharge, the patient progressively developed new back and leg pain for which she was re-admitted seven weeks later. This was investigated and initially thought to be myositis of the erector spinae muscles on magnetic resonance imaging. When the patient failed to respond to treatment, a muscle biopsy demonstrated desmoid fibromatosis. Trauma may cause or accelerate the development of desmoid fibromatosis, which has also been theorised to arise from scar tissue in previously injured areas. We hypothesise that challenging epidural placement or the leakage of the local anaesthetic agent into the surrounding muscular tissue, inducing local myonecrosis, could have been the triggering or accelerating event in tumour development. This may be the first reported case of extra-abdominal desmoid fibromatosis in association with epidural placement.

Quadriceps and Hamstring Strength in Adolescents 6 Months After ACL Reconstruction With Femoral Nerve Block, Adductor Canal Block, or No Nerve Block

Background:

Femoral nerve block (FNB) and adductor canal block (ACB) have been used increasingly for pain control during anterior cruciate ligament (ACL) reconstruction in adolescent patients. However, recent evidence suggests that the use of FNB may affect quadriceps strength recovery 6 months after surgery.

Purpose/Hypothesis:

To compare postoperative isokinetic strength in adolescents who received FNB, ACB, or no block for perioperative analgesia during ACL reconstruction. We anticipated lower postoperative quadriceps and hamstring isokinetic deficits in adolescents who received FNB as compared with ACB.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

Patients were included in the study if they had undergone hamstring tendon autograft ACL reconstruction by a single surgeon from July 2008 to January 2018 and if they underwent isokinetic muscle testing at 4 to 8 months postoperatively. The participants were divided into 3 groups (no block, FNB, and ACB), and we compared the deficit in percentages between the affected and unaffected limbs as calculated from the isokinetic quadriceps and hamstring strength testing at 60 and 180 deg/s. Between-group analysis was performed using analysis of variance, with an alpha of .05.

Results:

A total of 98 participants were included in the analysis (31 no block, 36 FNB, and 31 ACB). The mean ± SD age of the patients was 15.26 ± 1.15, 15.50 ± 1.42, and 15.71 ± 1.44, for no block, FNB, and ACB, respectively. At 5.61 months postoperatively, there was no significant difference across the 3 groups in isokinetic quadriceps deficits (P ≥ .99), and the only significant difference in isokinetic hamstring deficit was observed for peak flexion at 180 deg/s, in which the ACB group had lower peak torque than the FNB group (–9.80% ± 3.48% vs 2.37% ± 3.23%; P = .035). The ratio of participants with a deficit exceeding 15% did not differ significantly among the 3 groups.

Conclusion:

Contrary to previous research, our findings indicate only minimal difference in quadriceps strength among the 3 types of perioperative analgesia in adolescents approximately 6 months after ACL reconstruction. The only significant strength deficit was seen in the hamstrings of patients receiving ACB at peak flexion as compared with those receiving FNB.

MRI and muscle enzymes do not support the diagnosis of local anesthetic myotoxicity: a descriptive case series

BACKGROUND

The presence of thigh muscle edema as characterized by increased signal intensity on MRI has been used to support the diagnosis of presumed local anesthetic-induced myotoxicity reported after total knee arthroplasty (TKA) with continuous adductor canal block (CACB). However, neither postoperative baseline imaging appearance nor muscle enzyme values have been described in conjunction with this clinical scenario. Thus, the usefulness of MRI or enzymatic biomarkers of muscle injury for supporting the diagnosis of local anesthetic myotoxicity is unknown.

METHODS

This descriptive case series documents postoperative MRI appearance of the ipsilateral upper leg, plus preoperative and postoperative creatine phosphokinase and aldolase values in volunteer patients who underwent uncomplicated TKA with CACB.

RESULTS

In 27 volunteer patients with no postsurgical evidence of clinically relevant myotoxicity, anterior thigh muscle edema was universally evident on imaging (n=12) and muscle enzyme values (n=19) were normal or only slightly elevated.

CONCLUSIONS

The non-specificity of these findings suggests that MRI and near normal muscle enzyme levels are of limited diagnostic value when there is clinical suspicion of local anesthetic myotoxicity in the setting of TKA with CACB.

TRIAL REGISTRATION NUMBER

NCT04821245.

Lidocaine Inhibits Myoblast Cell Migration and Myogenic Differentiation Through Activation of the Notch Pathway

Purpose

To assess the cellular and molecular effects of lidocaine on muscles/myoblasts.

Methods

Cultured myogenic precursor (C2C12) cells were treated with varying concentrations of lidocaine.

Results

Cell viability of C2C12 cells was inhibited by lidocaine in a concentration-dependent manner, with concentrations ≥0.08%, producing a dramatic reduction in cell viability. These ≥0.08% concentrations of lidocaine arrested cell cycles of C2C12 cells in the G0/G1 phase. Moreover, lidocaine inhibited cell migration and myogenic processes in C2C12 cells at low concentrations. Results from QRT-PCR assays revealed that following treatment with lidocaine, Notch1, Notch2, Hes1, Csl and Dll4 all showed higher levels of expression, while no changes were observed in Mmal1, Hey1, Dll1 and Jag1.

Conclusion

This work provides the first description of the effects of lidocaine upon the regeneration of muscles and maintenance of satellite cells at the cellular and molecular levels. In specific, we found that the Dll4-Notch-Csl-Hes1 axis was up-regulated suggesting that the Notch signaling pathway was involved in producing these effects of lidocaine. These findings provide a new and important foundation for future investigations into the effects of drug therapies in muscle diseases.

Intra-articular Morphine and Ropivacaine Injection Provides Efficacious Analgesia As Compared With Femoral Nerve Block in the First 24 Hours After ACL Reconstruction: Results From a Bone-Patellar Tendon-Bone Graft in an Adolescent Population

Background:

Opioid consumption and patient satisfaction are influenced by a surgeon’s pain-management protocol as well as the use of adjunctive pain mediators. Two commonly utilized adjunctive pain modifiers for anterior cruciate ligament (ACL) reconstruction are femoral nerve blockade and intra-articular injection; however, debate remains regarding the more efficacious methodology.

Hypothesis:

We hypothesized that intra-articular injection with ropivacaine and morphine would be found to be as efficacious as a femoral nerve block for postoperative pain management in the first 24 hours after bone–patellar tendon–bone (BTB) ACL reconstruction.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

Charts were retrospectively reviewed for BTB ACL reconstructions performed by a single pediatric orthopaedic surgeon from 2013 to 2019. Overall, 116 patients were identified: 58 received intra-articular injection, and 58 received single-shot femoral nerve block. All patients were admitted for 24 hours. Pain scores were assessed every 4 hours. Morphine milligram equivalents (MMEs) consumed were tabulated for each patient.

Results:

Opioid use was 24.3 MMEs in patients treated with intra-articular injection versus 28.5 MMEs in those with peripheral block (P = .108). Consumption of MMEs was greater in the intra-articular group in the 0- to 4-hour period (7.1 vs 4.6 MMEs; P = .008). There was significantly less MME consumption in patients receiving intra-articular injection versus peripheral block at 16 to 20 hours (3.2 vs 5.6 MMEs; P = .01) and 20 to 24 hours (3.8 vs 6.5 MMEs; P < .001). Mean pain scores were not significantly different over the 24-hour period (peripheral block, 2.7; intra-articular injection, 3.0; P = .19).

Conclusion:

Within the limitations of this study, we could identify no significant difference in MME consumption between the single-shot femoral nerve block group and intra-articular injection group in the first 24 hours postoperatively. While peripheral block is associated with lower opioid consumption in the first 4 hours after surgery, patients receiving intra-articular block require fewer opioids 16 to 24 hours postoperatively. Given these findings, we propose that intra-articular injection is a viable alternative for analgesia in adolescent patients undergoing BTB ACL reconstruction.

[Forms of anesthesia in ophthalmology]

The range of anesthesiological procedures in ophthalmology has not changed significantly over the last decades, with local anesthesia clearly coming to the fore. The development of minimally invasive surgical techniques requires significantly less analgesia and economic constraints to shorten operating times. The increasing proportion of outpatient ophthalmic surgery requires a short analgesia of the surgical area with as few complications as possible. Nevertheless, the selection of the procedures, which are described here in detail, must be made individually for each patient. General anesthesia continues to have its place, especially in cases of reduced compliance and difficult surgical conditions. The close cooperation between anesthetists and ophthalmic surgeons, e.g. for analgosedation in the outpatient area, can create a very pleasant surgical experience for the patient. An important goal should always be sufficient anxiolysis, analgesia and, in special operations, sufficient akinesia.

Ablation of small conductance calcium-activated potassium type-2 channel (SK2) delays occurrence of bupivacaine-induced cardiotoxicity in isolated mouse hearts

Bupivacaine is frequently used for conducting regional anesthesia. When accidentally injected or excessively absorbed into circulation, bupivacaine can induce severe arrhythmia and potentially lead to cardiac arrest. The specific mechanisms underlying this cardiotoxicity, however, remain to be clarified. We transfected HEK-293 cells to express the small conductance calcium-activated potassium type-2 channel (SK2), and used a whole-cell patch clamp method in order to explore how bupivacaine affected these channels. We subsequently used SK2 knockout mice to explore the relevance of SK2 channels in bupivacaine-induced cardiotoxicity in isolating mouse hearts, mounting them on a Langendorff apparatus, and perfusing them with bupivacaine. Using this system, arrhythmia, asystole, and cardiac functions were monitored. We observed dose-dependent inhibition of SK2 channels by bupivacaine: half-maximal inhibitory concentration (IC50) value = 18.6 μM (95% CI 10.8-32.1). When SK2 knockout (SK2 -/-) or wild-type (WT) mice were perfused with Krebs-Henseleit buffer (KHB), we did not observe any instances of arrhythmia. When SK2 -/- mice or WT were perfused with KHB containing bupivacaine (40 μM), the time to arrhythmia (Tarrhythmia) and time to asystole (Tasystole) were both significantly longer in SK2 -/- mice relative to WT mice (P < 0.001). Similarly, SK2 -/- mice exhibited a significantly longer time to 25%, 50%, and 75% reductions in heart rate (HR) and rate-pressure product (RPP) relative to WT mice following bupivacaine perfusion (P < 0.001). These results reveal that bupivacaine was able to mediate a dose-dependent inhibition of SK2 channels in HEK-293 cells, and deletion of SK2 channels can delay bupivacaine-induced cardiotoxicity in isolated mouse hearts.

Extraplexus versus intraplexus ultrasound-guided interscalene brachial plexus block for ambulatory arthroscopic shoulder surgery: A randomized controlled trial

Background

This randomized study compared the efficacy and safety of extraplexus and intraplexus injection of local anesthetic for interscalene brachial plexus block.

Methods

208 ASA I-II patients scheduled for elective shoulder arthroscopy under general anesthesia and ultrasound-guided interscalene brachial plexus block were randomly allocated to receive an injection of 25mL ropivacaine 0.5% either between C5-C6 nerve roots (intraplexus), or anterior and posterior to the brachial plexus into the plane between the perineural sheath and scalene muscles (extraplexus). The primary outcome was time to loss of shoulder abduction. Secondary outcomes included block duration, perioperative opioid consumption, pain scores, block performance time, number of needle passes, onset of sensory blockade, paresthesia, recovery room length of stay, patient satisfaction, incidence of Horner’s syndrome, dyspnea, hoarseness, and post-operative nausea and vomiting.

Results

Time to loss of shoulder abduction was faster in the intraplexus group (log-rank p-value<0.0005; median [interquartile range]: 4 min [2–6] vs. 6 min [4–10]; p-value <0.0005). Although the intraplexus group required fewer needle passes (2 vs. 3, p<0.0005), it resulted in more transient paresthesia (35.9% vs. 14.5%, p = 0.0004) with no difference in any other secondary outcome.

Conclusion

The intraplexus approach to the interscalene brachial plexus block results in a faster onset of motor block, as well as sensory block. Both intraplexus and extraplexus approaches to interscalene brachial plexus block provide effective analgesia. Given the increased incidence of paresthesia with an intraplexus approach, an extraplexus approach to interscalene brachial plexus block is likely a more appropriate choice.

A well-tolerated core needle muscle biopsy process suitable for children and adults

Serial muscle biopsies within clinical trials for Duchenne muscular dystrophy (DMD) are critical to document therapeutic responses. Less invasive means of sampling muscle are needed. We analyzed a retrospective consecutive case-series cohort of vacuum-assisted core needle muscle biopsy procedures performed on healthy and dystrophic individuals at a single institution assessing for safety and reliability of obtaining sufficient high-quality biopsy tissue for histologic assessment in adult and pediatric subjects. Of 471 muscle cores from 128 biopsy procedures, 377-550 mg of total muscle tissue was obtained per procedure with mean core weight of 129 mg (SD, 25.1 mg). All biopsies were adequate for histological assessment. There were no significant adverse events. This core needle biopsy approach, when combined with improved sample processing, provides a safe means to consistently obtain muscle samples for diagnostic and clinical trial applications.

Bupivacaine-induced myotoxicity during a continuous perineural femoral block: case report

Introduction: Regional anesthesia is widely used for postoperative analgesia in total knee arthroplasty (TKA). Although it is a safe and effective procedure, serious complications may still develop. In the event of an unusual or torpid evolution, the possibility of local anesthetic-induced myotoxicity should be suspected. Case presentation: A 54-year old patient, American Society of Anesthesiologists (ASA) II, underwent TKA due to primary gonarthrosis. The analgesic technique used was a femoral nerve block associated with continuous perineural infusion. 24hours later, the patient’s medical condition deteriorated presenting pain, edema, and functional limitation of the thigh of the operated extremity. The symptoms were suggestive of myotoxicity, confirmed with diagnostic images leading to the removal of the catheter. The patient experienced then a significant improvement and was discharged 5 days after surgery. Conclusion: The diagnosis of myotoxicity from local anesthetics is rare, since its manifestations may be masked by the usual symptoms of the postoperative period. Early identification of the condition is fundamental to reduce its negative impact on the patient’s recovery and satisfaction. Since the scope of the damage depends particularly on the concentration and duration of the exposure to the local anesthetic agent, there is a need to implement protocols that enable an effective block with the lowest concentration and volume of the medication.

Pain management in the orthopaedic trauma patient: Non-opioid solutions

When treating pain in the orthopaedic trauma patient opioids have classically represented the mainstay of treatment. They are relatively inexpensive and modestly effective for basic pain management. However, they are fraught with considerable side effects as well as the very high risk of addiction. Their use in pain management has been implicated in the opioid epidemic. For this reason, as well as their only moderate efficacy, alternative modes of treatment have been sought for both the patient with isolated limb trauma and the patient with poly trauma. We review alternative treatment methods in pain management for those with isolated limb trauma and poly trauma. These methods include topical agents, as well as non steroidal anti-inflammatory medications, acetaminophen, gabapetoids, intravenous agents, varying degrees of local anesthetic infiltration and peripheral nerve blocks, and the newer modality of fascial plane blocks. Often, it is a combination of these analgesic modalities that gives the most optimum treatment for the trauma patient. This also, more frequently than not, must be individually tailored to the patient, as no two patients act the same in this regard. It is therefore of importance that the physician managing such patients's pain be experienced and well-versed in all these treatment modalities. We also provide a basic stepwise algorithm we have found useful in treating those with single extremity or single site trauma versus those patients with poly trauma and resultant multiple sources as pain generators. It is hoped that this breakdown of the different modalities along with a better understanding of each modality's potential benefits and indications will aid the surgeon in providing better care to patients following orthopedic trauma.

Review of adjuvants to local anesthetics in peripheral nerve blocks: Current and future trends

In recent anesthetic practice, peripheral nerve blocks (PNBs) are used extensively for surgical anesthesia and nonsurgical analgesia. PNBs offer many benefits over other anesthetic techniques in a certain population of patients, and in some specific clinical setting, that may contribute to faster and safer pain relief, increased patient satisfaction, reduced hospital stay, and decreased overall healthcare cost. The technique involves the injection of the anesthetic in the vicinity of a specific nerve or bundle of nerves to block the sensation of pain transmitting to a specific portion of the body. However, the length of analgesia when a single anesthetic is used for PNB may not last long. Therefore, the practice of adding an additional agent called adjuvant has been evolved to prolong the analgesic effect. There are many such adjuvants available that are clinically being used for this purpose imparting great efficacy and safety to the anesthetic process. The adjuvants molecules are generally classified as opioids, alpha-2 agonist, steroids, etc. Most of them are safe to use and show little or no adverse event related to neurotoxicity and tissue damage. Although there is extensive use of such adjuvants in the clinical field, none of the molecules is approved by the FDA and is used as an off-label drug. The risk to benefit ratio must be assessed while using such an agent. This review will try to delineate the basic need of adjuvant in peripheral nerve block and will discuss the advantages and limitations of using different adjuvants and will discuss the future prospect of such application.

Barbosa RT, Valenti VE, Oliveira FR, Roque AL, Júnior HMFES, Garner DM, Raimundo RD, de Abreu LC. The effects of cataract surgery on autonomic heart rate control: a prospective cross-sectional and analytical study

OBJECTIVES

We aimed to evaluate the effects of cataract surgery on cardiac autonomic modulation.

METHODS

A cross-sectional and analytical study was conducted at the Hospital Maria Braido in the city of São Caetano do Sul, São Paulo, between 2015 and 2016. We investigated 19 patients of both sexes who were all over 50 years old; all patients had a diagnosis of senile or bilateral cataracts and were recommended to undergo implantation of the intraocular lens. Heart rate variability (HRV) was evaluated before, during and after cataract surgery.

RESULTS

There were no significant changes in the time and geometric domains of HRV before, during or after surgery. The high-frequency (HF) band in normalized units (nu) on the spectral analysis significantly increased (p=0.02, Cohen's d=0.9, large effect size). However, the low-frequency (LF) band in nu significantly decreased during surgery (p=0.02, Cohen's d=0.9, large effect size).

CONCLUSION

Throughout the intraocular lens implantation cataract surgery, there was an increase in parasympathetic modulation and a decrease in the sympathetic component of the heart rate (HR). We propose that this result is attributable to the supine position of the patients during surgery and the trigeminal reflex.

Local Anesthetics: Pharmacology and Special Preparations

Local anesthetics are the only class of drugs that can block transduction and transmission of nociception. Physical properties, mechanism of action, and pharmacokinetics of this class of drugs are reviewed in this article. The clinical use, such intravenous administration of lidocaine, and local and systemic toxic effects are covered. A review of current studies published in the human and veterinary literature on lidocaine patches (Lidoderm) and liposomal bupivacaine (Experal and Nocita) are discussed.

Effect of bupivacaine and adjuvant drugs on skeletal muscle tissue oximetry and blood flow: an experimental study

Background

Skeletal muscle microvascular blood flow plays a critical role in many myopathologies. The influence of bupivacaine and adjuvants on skeletal muscle microvascular perfusion and tissue oximetry is poorly understood but might be a relevant risk factor for myopathies after local anesthetic administration. The aim of this experimental study was to determine the effects of bupivacaine alone or in combination with epinephrine or clonidine on skeletal muscle perfusion and tissue oximetry.

Methods

Combined tissue spectrophotometry and Laser-Doppler flowmetry and tissue oximetry were used to assess local muscle blood flow in anesthetized pigs after topical administration of test solutions (bupivacaine, bupivacaine with epinephrine or clonidine, saline). Measurements were performed for up to 60 mins.

Results

The application of bupivacaine alone did not alter relative muscle blood flow significantly, whereas the addition of epinephrine or clonidine to bupivacaine resulted in a significant reduction of relative muscle blood flow at T30 and T60. However, bupivacaine resulted in a significant decrease of tissue oximetry values when compared to saline control group at T30 and T60. The application of bupivacaine combined with clonidine or epinephrine resulted in no significant reduction of tissue oximetry when compared to bupivacaine alone.

Conclusion

Bupivacaine alone results in a significant decrease of tissue oximetry in skeletal muscle which is not increased by the addition of epinephrine or clonidine despite further reductions of microcirculatory perfusion. Overall, bupivacaine alone or with adjuvants does produce local muscle ischemia for which pathological consequences need to be addressed in further studies.

Peripheral nerve catheters: A critical review of the efficacy

Continuous peripheral nerve blocks are commonly used for postoperative analgesia after surgery. However, catheter failure may occur due to either primary (incorrect insertion) or secondary reasons (displacement, obstruction, disconnection). Catheter failure results in unanticipated pain, need for opioid use, and risk of readmission or delay in hospital discharge. This review aimed to assess definition and frequency of catheter failure, and discuss the alternatives to prolong duration of single-shot nerve blocks. A literature search was performed on peripheral catheters reporting failure as the main outcome measure. Thirty-three studies met the selection criteria, comprising 2711 catheters. Literature review suggests that peripheral nerve catheters have clinically significant failure rate when the assessment is performed using an objective (imaging) method. Subjective methods of assessment (without imaging) may underestimate the incidence of catheter failure.

LOCAL ANESTHETICS AND STEROIDS: CONTRAINDICATIONS AND COMPLICATIONS - CLINICAL UPDATE

The objective of this clinical update, based on recently published literature, was to discuss incidence and characteristics of the most relevant clinical adverse effects associated with local anesthetic and steroid use in regional anesthesia and treatment of acute or chronic pain. A comprehensive review of the English-language medical literature search utilizing PubMed, Ovid Medline® and Google Scholar from 2015 to 2018 was performed. This narrative review provides anesthesia practitioners with updated evidences on complications and contraindications of local anesthetic and steroid use with emphasis on current points of view regarding prevention, early diagnosis and treatment of adverse events.

Randomized controlled trial of a simplified adductor canal block performed for analgesia following total knee arthroplasty

Background and objectives

The objective of the study was to determine if injection of local anesthetic into the vastus medialis and sartorius muscles adjacent to the adductor canal produces sensory changes comparable with adductor canal block (ACB). This could result in a technically easier and potentially safer alternative to ACB.

Methods

In this randomized controlled trial, patients received either ACB (n=20) or a simplified adductor canal (SAC) block performed using a new fenestrated nerve block needle (n=20). The time to perform each block as well as the number of attempts to position the needle were evaluated. A non-inferiority test was used to compare pain scores and opioid requirements for the ACB and the SAC block.

Results

The SAC block was performed more rapidly, with fewer needle passes, and had a higher success rate than the ACB. Three block failures and two vessel punctures were observed in the ACB group, while none of these events occurred in SAC block patients. Analgesia and opioid consumption for patients treated with the SAC block were not inferior to ACB.

Conclusion

The SAC block is technically easier to perform and potentially safer than ACB. This procedure can be performed using easily visible ultrasound landmarks and has the potential for use among a wide range of healthcare providers.

Trial registration number

NCT02786888.