The differential effects of bupivacaine and lidocaine on prostaglandin E2 release, cyclooxygenase gene expression and pain in a clinical pain model

Rebound Pain After Peripheral Nerve Blockade-Bad Timing or Rude Awakening?

Patients who have perioperatively benefited from regional anesthesia frequently report moderate to severe pain when the nerve block effects fade away. Over the past years, the term "rebound pain" has been introduced, suggesting a specific pathologic process. It is debated whether significant pain on block resolution reflects a separate and distinct pathologic mechanism potentially involving proinflammatory and neurotoxic effects of local anesthetics, or is simply caused by the recovery of sensory function at a timepoint when nociceptive stimuli are still intense, and moderate to severe pain should be anticipated. In that latter case, the phenomenon referred to as rebound pain could be considered a failure of pain management providers to devise an adequate analgesia plan. Whatever the ultimate designation, management of rebound pain should be proactive, by implementing multimodal analgesia, or tailoring the blockade to the expected trajectory of postoperative pain and managing patient expectations accordingly. Until we know more about the etiology and impact of this phenomenon, the authors suggest a more neutral designation such as "pain on block resolution."

Regional anesthesia does not decrease inpatient or outpatient opioid demand in distal femur fracture surgery

INTRODUCTION

Regional anesthesia (RA) is sometimes used to decrease pain and opioid consumption in distal femur fractures. However, the real-world impact of RA on inpatient opioid consumption and outpatient opioid demand is not well known. The hypothesis of this study is that RA would be associated with decreased inpatient opioid consumption and outpatient opioid demand.

METHODS

This study evaluated inpatient post-operative opioid consumption (0-24 h, 24-48 h, 48-72 h) and outpatient opioid demand (discharge to 2 weeks, 6 weeks, and 90 days) in all patients ages 18 and older undergoing operative treatment of distal femur fractures at a single institution from 7/2013 to 7/2018 (n = 230). Unadjusted and adjusted multivariable models were used to evaluate the impact of RA and other baseline patient and operative characteristics on inpatient opioid consumption and outpatient opioid demand.

RESULTS

Adjusted models demonstrated a small, significant increase in inpatient opioid consumption in patients with RA compared to no RA (4.7 estimated OE's without RA vs 6.2 OE's with RA from 24- to 48-h post-op, p < 0.05) but otherwise no significant differences at other timepoints (6.7 estimated OE's without RA vs 6.9 OE's with RA from 0- to 24-h post-op and 4.5 vs 4.4 from 48- to 72-h post-op, p > 0.05). Estimated cumulative outpatient opioid demand was significantly higher in patients with RA from discharge to 6 weeks and to 90 days (55.8 OE's without RA vs 63.9 with RA from discharge to 2 weeks, p > 0.05; 74.9 vs 95.1 OE's to 6 weeks, and 85 vs 113.1 OE's to 90 days, p < 0.05).

DISCUSSION

In distal femur fracture surgery, RA was associated with increased inpatient and outpatient opioid demand after adjusting for baseline patient and treatment characteristics. These results call into question the routine use of RA in distal femur fractures.

LEVEL OF EVIDENCE

Level III, retrospective, therapeutic cohort study.

Development of Nanogel Loaded with Lidocaine for Wound-Healing: Illustration of Improved Drug Deposition and Skin Safety Analysis

A wound refers to a cut or blow that may result in primary or secondary infection or even death, if untreated. In the current study, we have explored the wound-healing properties of lidocaine nanogel, owing to its antioxidant and neutrophilic modulatory potential. Initially, the pre-formulation study was performed and then using central composite design (CCD) fabrication and the characterization of lidocaine-loaded nanoemulsion was carried out. After the preparation of a nanogel of lidocaine-loaded nanoemulsion, it was evaluated on various parameters, such as pH, spreadability, extrudability, drug content, in vitro drug release, dermatokinetic study and in vivo skin safety. Based on the pre-formulation study, the maximum solubility of lidocaine was found in oleic acid (324.41 ± 4.19 mg/mL) and in Tween 20 (192.05 ± 8.25 mg/mL), selected as a suitable emulsifier. The refractive index of the optimized nanoemulsion was found to be 1.35 ± 0.04, the electrokinetic potential was recorded as −15.47 ± 0.95 mV. The pH, spreadability and extrudability of nanogel was found to be 6.87 ± 0.51, 73.32 ± 4.59 gm.cm/sec and 107.41 ± 6.42 gm/cm2, respectively. The percentage of the cumulative drug content and drug release from nanogel was found to be 99.94 ± 1.70% and 93.00 ± 4.67%, respectively. Moreover, dermatokinetic study showed significantly (p < 0.0005) improved drug deposition and the in vivo skin safety study showed no sign of dermal erythematous lesion or any visible damage. Stability studies also testified the secureness of nanogel after storage in a prescribed environmental condition. Thus, this study provides substantial evidence for healing wounds effectively and the further evaluation of the in vivo model. The patent related to this work was published in the Indian Official Journal of the Patent Office (Issue number: 20/2022).

Intra-articular triamcinolone hexacetonide injections in hands osteoarthritis ‒ A double-blinded randomized controlled trial with a one year follow-up

OBJECTIVE

to evaluate the effectiveness of triamcinolone Hexacetonide (TH) Intra-Articular Injection (IAI) in hand Interphalangeal Joints (IP) of Osteoarthritis (OA) patients to improve pain and joint swelling; improve function, goniometry, and grasping force, and assess IAI influence on radiographic evolution over 1-year.

METHODS

A randomized, double-blind study. 60 patients who underwent IAI at the most symptomatic IP joint were randomly assigned to receive TH+Lidocaine (LD) (TH/LD group) or just LD (LD group). Patients were assessed blindly for 1-year, at baseline and 1, 4, 8, 12, and 48 weeks. The following variables were assessed: articular pain and swelling, AUSCAN and COCHIN functional questionnaires, grip and pinch strength, goniometry, perception of improvement, acetaminophen consumption, and simple radiography. Repeated-measures ANOVA test was used to analyze the intervention response.

RESULTS

Sixty patients completed the follow-up. There were nine missed assessments. 97% were women; mean age of 61-years (SD = 8.2), and approximately 5-years of disease (SD = 3.6). Half of the patients present radiographic classification Kellgren and Lawrence (KL) grades I and II, and the other half grades III and IV. The two groups evolved similarly at 48-weeks. TH/LD group had a better evaluation in joint swelling and acetaminophen consumption (p = 0.04 and p < 0.001, respectively) at 48-weeks. Radiographically there was no statistical difference between groups (KL, p = 0.564; erosive OA, p = 0.999; worsening, p = 0.573).

CONCLUSION

The IAI IP hands OA is effective for the improvement of joint swelling and decrease of analgesic consumption and does not influence the radiographic evolution of the injected joint.

[Rebound pain-From definition to treatment]

Hintergrund

Rebound pain als Nebenwirkung einer Regionalanästhesie ist ein übermäßiges Schmerzempfinden nach Abklingen der Wirkung der lokalen Betäubung, welches deutlich über den normalen Wundschmerz nach einer Operation hinausgeht. Dieses Phänomen rückt seit ca. 10 Jahren stärker in den Fokus der Forschung. Die konkreten Ursachen sind bisher unklar, und es existieren auch noch keine zielgerichteten Therapieempfehlungen.

Ziel der Arbeit

Dieser Übersichtsartikel soll der Leserschaft einen Überblick über den aktuellen Stand der Forschung geben. Es werden die Theorien zur Pathophysiologie vorgestellt und Prophylaxe- sowie Behandlungsstrategien erläutert.

Material und Methoden

Für diese Übersichtsarbeit wurden die von 2005 bis Mai 2021 auf PubMed erschienenen Publikationen zum Thema Rebound pain durchgesehen und die Definitionen der Autoren zu Rebound pain sowie die Annahmen zur Pathophysiologie und Therapieempfehlungen zusammengefasst.

Ergebnisse und Diskussion

Insgesamt wurden 22 Originalarbeiten im Hinblick auf die Definition von Rebound pain, die Annahme der Entstehung sowie Therapieoptionen ausgewertet. Dabei zeigt sich, dass keine einheitliche Definition existiert, die Pathophysiologie nicht eindeutig geklärt ist und zum aktuellen Zeitpunkt auch noch keine klaren Empfehlungen zu Prophylaxe sowie Therapie gegeben werden können.

Zusatzmaterial online

Die Online-Version dieses Beitrags (10.1007/s00101-022-01120-z) enthält eine tabellarische Zusammenstellung über Studiendesign sowie Kernaussagen der vorgestellten Studien.

Regional anesthesia does not decrease inpatient or outpatient opioid demand in femoral shaft fracture surgery

INTRODUCTION

Regional anesthesia (RA) may be used in femoral shaft fracture surgery to decrease pain and opioid consumption. However, the impact of RA on inpatient and outpatient opioid demand in patients undergoing femoral shaft fracture surgery is largely unknown. The aim of this study was to evaluate the impact of RA on inpatient opioid consumption and outpatient opioid demand in patients undergoing femoral shaft fracture surgery.

METHODS

Inpatient opioid consumption and outpatient opioid demand in all patients undergoing femoral shaft fracture surgery was recorded at a single, Level I trauma center from 7/2013 - 7/2018 (n=436). In addition to RA, baseline and treatment factors including age, sex, race, body mass index (BMI), smoking, chronic opioid use, American Society of Anesthesiologists (ASA) score, injury mechanism, additional injuries, open injury, and additional inpatient surgery were recorded. Unadjusted and adjusted multivariable models were used to evaluate the impact of RA on inpatient opioid consumption and outpatient opioid demand.

RESULTS

Adjusted models demonstrated increases in inpatient opioid consumption in patients with RA (6.9 estimated OE's without RA vs 8.8 OE's with RA from 48-72 hours post-op, p<0.05) but no significant differences at other timepoints (10.3 estimated OE's without RA vs 9.2 OE's with RA from 0-24 hours post-op, 8.2 vs 8.8 from 24-48 hours post-op, p>0.05). Estimated cumulative outpatient opioid demand did not differ significantly in patients with RA (82.3 OE's without RA vs 94.8 with RA from discharge to two-weeks, 105.4 vs 116.3 OE's to 6-weeks, and 124.5 vs 137.9 OE's to 90-days, all p>0.05). Late opioid refills were significantly more common in patients with RA (1.57 odds at 2-weeks to 6-weeks, 1.69 odds at 6-weeks to 90-days, p<0.05) DISCUSSION: In femoral shaft fracture surgery, RA was not associated with decreased opioid demand after adjusting for baseline patient and treatment characteristics. These results provide a real-world estimate of the impact of RA on opioid demand in femoral shaft fracture surgery and encourage providers to seek alternative analgesic modalities.

LEVEL OF EVIDENCE

Level III, retrospective, therapeutic cohort study.

Regional anesthesia does not decrease opioid demand in pelvis and acetabulum fracture surgery

INTRODUCTION

Patients with pelvic and acetabular fractures often have considerable pain in the perioperative period. Regional anesthesia (RA) including peripheral nerve blocks and spinal analgesia may reduce pain. However, the real-world impact of these modalities on inpatient opioid consumption and outpatient opioid demand is largely unknown. The purpose of this study was to evaluate the impact of perioperative RA on inpatient opioid consumption and outpatient opioid demand.

METHODS

This is a retrospective, observational review of inpatient opioid consumption and outpatient opioid demand in all patients ages 18 and older undergoing operative fixation of pelvic and acetabular fractures at a single Level, I trauma center from 7/1/2013-7/1/2018 (n = 205). Unadjusted and adjusted analyses were constructed to evaluate the impact of RA on inpatient opioid consumption and outpatient opioid demand while controlling for age, sex, race, body mass index (BMI), smoking, chronic opioid use, ASA score, injury mechanism, additional injuries, open injury, and additional inpatient surgery.

RESULTS

Adjusted models demonstrated increases in inpatient opioid consumption in patients with RA (12.6 estimated OE's without RA vs 16.1 OE's with RA from 48 to 72 h post-op, p < 0.05) but no significant differences at other timepoints (17.5 estimated OE's without RA vs 16.8 OE's with RA from 0 to 24 h post-op, 15.3 vs 17.1 from 24 to 48 h post-op, p > 0.05). Estimated cumulative outpatient opioid demand was significantly higher in patients with RA at discharge to 90 days post-op (and 156.8 vs 207.9 OE's to 90 days, p < 0.05) but did not differ significantly before that time (121.5 OE's without RA vs 123.9 with RA from discharge to two weeks, 145.2 vs 177.2 OE's to 6 weeks, p > 0.05).

DISCUSSION

In pelvis and acetabulum fracture surgery, RA was associated with increased inpatient and outpatient opioid demand after adjusting for baseline patient and treatment characteristics. Regional anesthesia may not be beneficial for these patients.

Comparison of efficacy and pain perception using 0.5% Bupivacaine and 2% Lidocaine in periodontal Surgery - A split mouth randomized clinical trial

PURPOSE

To evaluate the effectiveness of bupivacaine and lidocaine local anesthesia on the intra-surgical and post-surgical pain control in patients undergoing periodontal flap surgery.

MATERIALS AND METHODS

A randomized, single-blind, split-mouth design was employed in patients who are scheduled for periodontal flap surgery for at least two similar sextants with similar anesthetic techniques. Fifty patients (age range 16-65 years, 32 males and 28 females) enrolled in the present study. On one-site, the flap surgery was performed using 2% lidocaine with 1:200000 epinephrine and on the other with 0.5% bupivacaine with 1:200000 epinephrine. Base line clinical parameters, probing pocket depth, clinical attachment level were recorded. Pain during intra operative period, at the time of loss of numbness and for three consecutive days was measured using visual analog scale (VAS).

RESULTS

Significant differences were observed between the two groups in the intra operative pain scores (p=0.0045) and pain scores at the time of loss of numbness (p=0.0005) but not at the 1st, 2nd and 3rd day after the surgery.

CONCLUSION

Bupivacaine was markedy more effective than the lidocaine. Thus the usage of bupivacaine can be substantiated for periodontal surgeries for the control of pain in the intra operative and immediate post-operative period to increase patients' comfort.

The effect of perineural dexamethasone on rebound pain after ropivacaine single-injection nerve block: a randomized controlled trial

BACKGROUND

Rebound pain after a single-shot nerve block challenges the real benefit of this technique. We aimed to investigate whether perineural dexamethasone addition decreased the incidence of rebound pain after a single-shot nerve block.

METHODS

We randomly allocated 132 patients scheduled for open reduction internal fixation of an upper extremity closed fracture under single-shot peripheral nerve block and sedation into two groups. Patients in the dexamethasone group received nerve block with 0.375% ropivacaine and 8 mg dexamethasone, while those in the control group received ropivacaine only. Sixty-three patients in the dexamethasone group and 60 patients in the control group were analyzed for the incidence of rebound pain 48 h after block administration, which was the primary outcome. The secondary outcomes included the highest self-reported numeric rating scale (NRS) pain score, and NRS at 8, 12, 24, and 48 h after the block, sufentanil consumption, sleep quality on the night of surgery, patient satisfaction with the pain therapy, blood glucose at 6 h after the block, pain and paresthesia at 30 days after surgery.

RESULTS

The incidence of rebound pain was significantly lower in the dexamethasone group (7 [11.1%] of 63 patients) than in the control group (28 [48.8%] of 60 patients [RR = 0.238, 95% CI (0.113-0.504), p = 0.001]. Dexamethasone decreased opioid consumption in 24 h after surgery (p < 0.001) and improved the sleep quality score on the night of surgery (p = 0.01) and satisfaction with pain therapy (p = 0.001). Multivariate logistic regression analysis showed that only group allocation was associated with the occurrence of rebound pain [OR = 0.062, 95% CI (0.015-0.256)]. Patients in the dexamethasone group reported later onset pain (19.7 ± 6.6 h vs 14.7 ± 4.8 h since block administration, mean ± SD, p < 0.001) and lower peak NRS scores [5 (3, 6) vs 8 (5, 9), median (IQR), p < 0.001] than those in the control group.

CONCLUSIONS

The perineural administration of 8 mg dexamethasone reduces rebound pain after a single-shot nerve block in patients receiving ORIF for an upper limb fracture.

TRIAL REGISTRATION

This study was retrospectively registered in the Chinese Clinical Trial Registry ( ChiCTR-IPR-17011365 ) on May 11th, 2017.

Anaesthesia, pain and recovery profiles in children following dental extractions

The aim of this prospective cohort study was to describe the anaesthetic practices, rates of postoperative pain and the recovery trajectory of children having urgent dental extractions at our institution. Demographic, anaesthetic and surgical details of children undergoing dental extractions were obtained by case note review. Parent-proxy pain scores were collected via telephone on the day of surgery and on postoperative days, as well as details of analgesia given, behavioural disturbance, and nausea and vomiting. Follow-up was continued until each child no longer had pain. Datasets were analysed for 143 patients. Fasting times were prolonged, with 81 children (56.6%) fasted for over four hours from fluids. Moderate or severe pain was recorded in 14 children (9.8%) postoperatively on the day of surgery, with higher rates in children who had a greater number of teeth extracted. Low rates of moderate to severe pain were observed during follow-up, affecting six children (4.2%) on postoperative day 1 and three children (2.1%) on postoperative day 2 with primarily simple analgesia administered at home. Only eight children (5.6%) had nausea and/or vomiting on the day of surgery. Rates of reported behavioural disturbance at home were low, extending beyond the second postoperative day in only two children (1.4%), and only four children (2.8%) attended a dentist during the follow-up period. In conclusion, the low rates of pain and nausea and vomiting reported in the days following surgery for urgent dental procedures suggest that children can be cared for at home with simple analgesia.

Managing rebound pain after regional anesthesia

Rebound pain after regional anesthesia can be defined as transient acute postoperative pain that ensues following resolution of sensory blockade, and is clinically significant, either with regard to the intensity of pain or the impact on psychological well-being, quality of recovery, and activities of daily living. Current evidence suggests that it represents an unmasking of the expected nociceptive response in the absence of adequate systemic analgesia, rather than an exaggerated hyperalgesic phenomenon induced by local anesthetic neural blockade. In the majority of patients, it does not appear to significantly impact cumulative postoperative opioid consumption, quality of recovery, or patient satisfaction, and is not associated with longer-term sequelae such as persistent post-surgical pain. Nevertheless, it must be considered whenever regional anesthesia is incorporated into perioperative management. Strategies to mitigate the impact of rebound pain include routine prescribing of a systemic multimodal analgesic regimen, as well as patient education on appropriate expectations regarding block offset and expected surgical pain, and timely initiation of analgesic medication. Prolonging the duration of action of regional anesthesia with continuous catheter techniques or local anesthetic adjuncts may also help alleviate rebound pain, although further research is required to confirm this.

Does Rebound Pain after Peripheral Nerve Block for Orthopedic Surgery Impact Postoperative Analgesia and Opioid Consumption? A Narrative Review

Regional anesthesia has been considered a great tool for maximizing post-operative pain control while minimizing opioid consumption. Post-operative rebound pain, characterized by hyperalgesia after the peripheral nerve block, can however diminish or negate the overall benefit of this modality due to a counter-productive increase in opioid consumption once the block wears off. We reviewed published literature describing pathophysiology and occurrence of rebound pain after peripheral nerve blocks in patients undergoing orthopedic procedures. A search of relevant keywords was performed using PubMed, EMBASE, and Web of Science. Twenty-eight articles (n = 28) were included in our review. Perioperative considerations for peripheral nerve blocks and other alternatives used for postoperative pain management in patients undergoing orthopedic surgeries were discussed. Multimodal strategies including preemptive analgesia before the block wears off, intra-articular or intravenous anti-inflammatory medications, and use of adjuvants in nerve block solutions may reduce the burden of rebound pain. Additionally, patient education regarding the possibility of rebound pain is paramount to ensure appropriate use of prescribed pre-emptive analgesics and establish appropriate expectations of minimized opioid requirements. Understanding the impact of rebound pain and strategies to prevent it is integral to effective utilization of regional anesthesia to reduce negative consequences associated with long-term opioid consumption.

Use of 0.5% bupivacaine with buprenorphine in minor oral surgical procedures

Background:

Minor oral surgical procedures are the most commonly performed procedures by oral and maxillofacial surgeons. Performance of painless surgical procedure is highly appreciated by the patients and is possible through the use of local anesthesia, conscious sedation or general anesthesia. Postoperative pain can also be controlled by the use of opioids, as opioid receptors exist in the peripheral nervous system and offers the possibility of providing postoperative analgesia in the surgical patient. The present study compares the efficacy of 0.5% bupivacaine versus 0.5% bupivacaine with 0.3 mg buprenorphine in minor oral surgical procedures.

Patients and Methods:

The present study was conducted in 50 patients who required minor oral surgical procedures under local anesthesia. Two types of local anesthetic solutions were used- 0.5% bupivacaine with 1:200000 epinephrine in group I and a mixture of 39 ml of 0.5% bupivacaine with epinephrine 1:200000 and 1 ml of 300 μg buprenorphine (3 μg/kg)in group II. Intraoperative and postoperative evaluation was carried out for both the anesthetic solutions.

Results:

The mean duration of postoperative analgesia in bupivacaine group (508.92 ± 63.30 minutes) was quite less than the buprenorphine combination group (1840.84 ± 819.51 minutes). The mean dose of postoperative analgesic medication in bupivacaine group (1.64 ± 0.99 tablets) was higher than buprenorphine combination group (0.80 ± 1.08 tablets). There was no significant difference between the two groups regarding the onset of action of the anesthetic effect and duration of anesthesia.

Conclusion:

Buprenorphine can be used in combination with bupivacaine for patients undergoing minor oral surgical procedures to provide postoperative analgesia for a longer duration.

Comparison of liposomal and 2-hydroxypropyl-β-cyclodextrin–lidocaine on cell viability and inflammatory response in human keratinocytes and gingival fibroblasts

Objectives

The aim of this study was to observe the effect multilamellar liposomes (MLV) and 2-hydroxypropyl-β-cyclodextrin (HP-β-CD) in the in-vitro effects of lidocaine in cell viability, pro-inflammatory cytokines and prostaglandin E2 release of both human keratinocytes (HaCaT) and gingival fibroblasts (HGF) cells.

Methods

HaCaT and HGF cells were exposed to lidocaine 100–1 μm in plain, MLV and HP-β-CD formulations for 6 h or 24 h. The formulation effects in cell viability were measured by XTT assay and by fluorescent labelling. Cytokines (IL-8, IL-6 and TNF-α) and PGE2 release were quantified by ELISA.

Key findings

MLV and HP-β-CD formulations did not affect the HaCaT viability, which was significantly decreased by plain lidocaine after 24 h of exposure. Both drug carriers increased all cytokines released by HGF after 24-h exposure, and none of the carriers was able to reduce the PGE2 release induced by lidocaine.

Conclusion

The effect of drug carrier in the lidocaine effects was dependent on the cell type, concentration and time of exposure. MLV and HP-β-CD showed benefits in improving cell viability; however, both of them showed a tendency to increase cytokine release when compared to the plain solution.

Genome-wide association studies suggest sex-specific loci associated with abdominal and visceral fat

BACKGROUND

To identify loci associated with abdominal fat and replicate prior findings, we performed genome-wide association (GWA) studies of abdominal fat traits: subcutaneous adipose tissue (SAT); visceral adipose tissue (VAT); total adipose tissue (TAT) and visceral to subcutaneous adipose tissue ratio (VSR).

SUBJECTS AND METHODS

Sex-combined and sex-stratified analyses were performed on each trait with (TRAIT-BMI) or without (TRAIT) adjustment for body mass index (BMI), and cohort-specific results were combined via a fixed effects meta-analysis. A total of 2513 subjects of European descent were available for the discovery phase. For replication, 2171 European Americans and 772 African Americans were available.

RESULTS

A total of 52 single-nucleotide polymorphisms (SNPs) encompassing 7 loci showed suggestive evidence of association (P<1.0 × 10(-6)) with abdominal fat in the sex-combined analyses. The strongest evidence was found on chromosome 7p14.3 between a SNP near BBS9 gene and VAT (rs12374818; P=1.10 × 10(-7)), an association that was replicated (P=0.02). For the BMI-adjusted trait, the strongest evidence of association was found between a SNP near CYCSP30 and VAT-BMI (rs10506943; P=2.42 × 10(-7)). Our sex-specific analyses identified one genome-wide significant (P<5.0 × 10(-8)) locus for SAT in women with 11 SNPs encompassing the MLLT10, DNAJC1 and EBLN1 genes on chromosome 10p12.31 (P=3.97 × 10(-8) to 1.13 × 10(-8)). The THNSL2 gene previously associated with VAT in women was also replicated (P=0.006). The six gene/loci showing the strongest evidence of association with VAT or VAT-BMI were interrogated for their functional links with obesity and inflammation using the Biograph knowledge-mining software. Genes showing the closest functional links with obesity and inflammation were ADCY8 and KCNK9, respectively.

CONCLUSIONS

Our results provide evidence for new loci influencing abdominal visceral (BBS9, ADCY8, KCNK9) and subcutaneous (MLLT10/DNAJC1/EBLN1) fat, and confirmed a locus (THNSL2) previously reported to be associated with abdominal fat in women.

Effectiveness of Triamcinolone Hexacetonide Intraarticular Injection in Interphalangeal Joints: A 12-week Randomized Controlled Trial in Patients with Hand Osteoarthritis

Objective.

To evaluate the effectiveness and tolerance of intraarticular injection (IAI) of triamcinolone hexacetonide (TH) for the treatment of osteoarthritis (OA) of hand interphalangeal (IP) joints.

Methods.

Sixty patients who underwent IAI at the most symptomatic IP joint were randomly assigned to receive TH/lidocaine (LD; n = 30) with TH 20 mg/ml and LD 2%, or just LD (n = 30). The injected joint was immobilized with a splint for 48 h in both groups. Patients were assessed at baseline and at 1, 4, 8, and 12 weeks by a blinded observer. The following variables were assessed: pain at rest [visual analog scale (VAS)r], pain at movement (VASm), swelling (physician VASs), goniometry, grip and pinch strength, hand function, treatment improvement, daily requirement of paracetamol, and local adverse effects. The proposed treatment (IAI with TH/LD) was successful if statistical improvement (p < 0.05) was achieved in at least 2 of 3 VAS. Repeated-measures ANOVA test was used to analyze intervention response.

Results.

Fifty-eight patients (96.67%) were women, and the mean age was 60.7 years (± 8.2). The TH/LD group showed greater improvement than the LD group for VASm (p = 0.014) and physician VASs (p = 0.022) from the first week until the end of the study. In other variables, there was no statistical difference between groups. No significant adverse effects were observed.

Conclusion.

The IAI with TH/LD has been shown to be more effective than the IAI with LD for pain on movement and joint swelling in patients with OA of the IP joints. Regarding pain at rest, there was no difference between groups. Trial registration number: ClinicalTrials.gov (NCT02102620).

A Comparative Study Between Bupivacaine with Adrenaline and Carbonated Bupivacaine with Adrenaline for Surgical Removal of Impacted Mandibular Third Molar

OBJECTIVES

To compare the effectiveness of bupivacaine with adrenaline with that of carbonated bupivacaine with adrenaline on pain, onset of anesthesia and duration of anesthesia following surgical removal of impacted mandibular third molar.

STUDY DESIGN

All the patients who underwent surgical removal of impacted mandibular third molar and who fulfilled our inclusion and exclusion criteria from 1st June 2013 to 30th June 2014 were included in our study. Patients who were diagnosed as having impacted mandibular third molar were randomly allocated to two groups namely group A (bupivacaine with adrenaline), group B (carbonated bupivacaine with adrenaline). Pain during deposition of local anesthetic, onset of anesthesia and duration of anesthesia were compared between the two groups. The collected data were subjected to statistical analysis by Chi Square test, Mann-Whitney U test.

RESULTS AND CONCLUSION

The efficacy of carbonated bupivacaine with adrenaline is more compared with bupivacaine with adrenaline in decreasing pain on deposition of local anesthetic solution and in rapid onset of anesthesia. The duration of anesthesia for carbonated bupivacaine with adrenaline and bupivacaine with adrenaline had no significant difference. The use of carbonated bupivacaine with adrenaline will reduce the patient discomfort both intra-operatively and post-operatively.

Dexamethasone as adjuvant to bupivacaine prolongs the duration of thermal antinociception and prevents bupivacaine-induced rebound hyperalgesia via regional mechanism in a mouse sciatic nerve block model

Background

Dexamethasone has been studied as an effective adjuvant to prolong the analgesia duration of local anesthetics in peripheral nerve block. However, the route of action for dexamethasone and its potential neurotoxicity are still unclear.

Methods

A mouse sciatic nerve block model was used. The sciatic nerve was injected with 60ul of combinations of various medications, including dexamethasone and/or bupivacaine. Neurobehavioral changes were observed for 2 days prior to injection, and then continuously for up to 7 days after injection. In addition, the sciatic nerves were harvested at either 2 days or 7 days after injection. Toluidine blue dyeing and immunohistochemistry test were performed to study the short-term and long-term histopathological changes of the sciatic nerves. There were six study groups: normal saline control, bupivacaine (10mg/kg) only, dexamethasone (0.5mg/kg) only, bupivacaine (10mg/kg) combined with low-dose (0.14mg/kg) dexamethasone, bupivacaine (10mg/kg) combined with high-dose (0.5mg/kg) dexamethasone, and bupivacaine (10mg/kg) combined with intramuscular dexamethasone (0.5mg/kg).

Results

High-dose perineural dexamethasone, but not systemic dexamethasone, combined with bupivacaine prolonged the duration of both sensory and motor block of mouse sciatic nerve. There was no significant difference on the onset time of the sciatic nerve block. There was “rebound hyperalgesia” to thermal stimulus after the resolution of plain bupivacaine sciatic nerve block. Interestingly, both low and high dose perineural dexamethasone prevented bupivacaine-induced hyperalgesia. There was an early phase of axon degeneration and Schwann cell response as represented by S-100 expression as well as the percentage of demyelinated axon and nucleus in the plain bupivacaine group compared with the bupivacaine plus dexamethasone groups on post-injection day 2, which resolved on post-injection day 7. Furthermore, we demonstrated that perineural dexamethasone, but not systemic dexamethasone, could prevent axon degeneration and demyelination. There was no significant caspase-dependent apoptosis process in the mouse sciatic nerve among all study groups during our study period.

Conclusions

Perineural, not systemic, dexamethasone added to a clinical concentration of bupivacaine may not only prolong the duration of sensory and motor blockade of sciatic nerve, but also prevent the bupivacaine-induced reversible neurotoxicity and short-term “rebound hyperalgesia” after the resolution of nerve block.

Effects of opioids on local anesthesia in the rat: a codeine and tramadol study

Opioids are central analgesics that act on the CNS (central nervous system) and PNS (peripheral nervous system). We investigated the effects of codeine (COD) and tramadol (TRAM) on local anesthesia of the sciatic nerve. Eighty Wistar male rats received the following SC injections in the popliteal fossa: local anesthetic with epinephrine (LA); local anesthetic without vasoconstrictor (LA WV); COD; TRAM; LA + COD; LA + TRAM; COD 20 minutes prior to LA (COD 20' + LA) or TRAM 20 minutes prior to LA (TRAM 20' + LA). As a nociceptive function, the blockade was considered the absence of a paw withdraw reflex. As a motor function, it was the absence of claudication. As a proprioceptive function, it was the absence of hopping and tactile responses. All data were compared using repeated-measures analysis of variance (ANOVA). Opioids showed a significant increase in the level of anesthesia, and the blockade duration of LA + COD was greater than that of the remaining groups (p < 0.05). The associated use of opioids improved anesthesia efficacy. This could lead to a new perspective in controlling dental pain.

Effect of local anaesthetic infiltration with bupivacaine and ropivacaine on wound healing: a placebo-controlled study

Infiltration of surgical wounds with long-acting local anaesthetics (LA) is used to reduce postoperative incisional pain. We hypothesised that infiltration with LA interferes with wound healing in rats. Seventy-two rats were allocated into nine groups. After intraperitoneal anaesthesia, the interscapular dorsal region was infiltrated with equivolumes of saline, 0·5% bupivacaine or ropivacaine, in a randomised double-blind fashion. A standardised incision was performed in the infiltrated area and sutured closed. The rats were euthanised on the 3rd or 14th day after the operation and tissue from the incision site was subjected to histochemical analyses and mechanical testing (MT). Compared with the control group, bupivacaine displayed a significant increase in the macrophage number on day 3 (+63% versus +27% for ropivacaine). The transforming growth factor β-1 expression had a significant increase in the LA (versus saline) groups, +63% in ropivacaine group and +115% in bupivacaine group on day 3 (P < 0·05). The collagen fibres as measured by dyed area were significantly higher in the bupivacaine group on day 3 (+56%, P < 0·01 versus +15% for ropivacaine). CD34 was reduced in bupivacaine group (-51%, P < 0·05 versus +3% for ropivacaine). On day 14, no statistical differences were observed in either LA group (versus saline) with respect to histopathologic or inflammatory mediators. MT on day 14 showed no differences between the LA and saline groups. The LA-induced increases in histological markers did not extend beyond the third day, suggesting that wound infiltration with long-acting LA does not impair the wound healing process in rats.

Effect of bupivacaine on postoperative pain for inferior alveolar nerve block anesthesia after single-visit root canal treatment in teeth with irreversible pulpitis

INTRODUCTION

Pain control after root canal treatment is of great importance in endodontic practice. The aim of the present study was to investigate the effect of a long-acting anesthetic (bupivacaine) on postoperative pain and the use of analgesics after root canal treatment.

METHODS

In a randomized double-blinded clinical trial, 60 patients (30 per group) having first or second mandibular molars with irreversible pulpitis randomly received either 0.5% bupivacaine with 1:200,000 epinephrine or 2% lidocaine with 1:80,000 epinephrine as the anesthetic solutions for inferior alveolar nerve blocks. After single-visit root canal treatment, each patient recorded their pain score on a visual analogue scale at 6, 12, 24, 36, 48, and 72 hours after treatment. Data were analyzed by Mann-Whitney, χ(2), Cochrane Q, and t tests as well as Pearson correlation analysis.

RESULTS

The results indicate that patients who received bupivacaine had significantly lower pain scores at 6 and 12 hours after root canal treatment compared with the patients who received lidocaine (P < .05). The use of analgesics in the bupivacaine patients was significantly lower than in the lidocaine group (P < .05).

CONCLUSIONS

Patients who received bupivacaine as the anesthetic agent for single-visit endodontic treatment of irreversible pulpitis in mandibular molars had significantly less early postoperative pain and used fewer analgesics than those who had lidocaine as the anesthetic.

Bupivacaine-enhanced small intestinal submucosa biomaterial as a hernia repair device

Management of post-surgical pain following herniorrhaphy remains a clinical challenge and novel methods to deliver analgesic compounds could be of great benefit. Because there is great interest in the use of natural biomaterials for hernia repair, we investigated the biocompatibility of a natural biomaterial, porcine small intestinal submucosa (SIS), which was impregnated with bupivacaine (SIS-B) via immersion in a solution of poly(lactic-co-glycolic acid) (PLGA). Groups of Sprague Dawley rats underwent surgical creation of a ventral abdominal wall defect with subsequent repair using either SIS or SIS-B. Analysis of serial blood samples showed peak bupivacaine levels (83 ng/mL) were achieved 16 h after implantation of SIS-B. One month after surgery, the rats were euthanized and implant sites harvested for mechanical strength testing and histological analysis. At the time of necropsy, adhesion extent and tenacity was greater in SIS-B rats, with 90% of SIS-B rats have adhesion to the implant site compared to only 75% of SIS rats. Microscopically, SIS implant sites were characterized by small amounts of residual SIS surrounded by mild-to-moderate chronic inflammation. In contrast, rats treated with SIS-B, residual SIS-B was surrounded by a ring of acute inflammatory cells and an outer ring of chronic inflammatory cells, possibly due to bupivacaine or residual PLGA. Mechanical strength testing of the harvested implant sites showed no significant (p ≤ 0.05) difference between SIS and SIS-B implants. In summary, bupivacaine is readily elaborated from SIS-B; and impregnation of SIS with bupivacaine does not substantially alter the biocompatibility of the biomaterial or its mechanical strength following implantation.

Long-acting local anesthetics and perioperative pain management

Although the use of long-acting local anesthetics has become a useful therapeutic approach for managing peri- and postoperative pain, recent evidence reveals unexpected outcomes. This article reviews the clinical use of long-acting local anesthetics, presents current clinical research findings, and makes recommendations for their use.

Continuous subcutaneous instillation of bupivacaine compared to saline reduces interleukin 10 and increases substance P in surgical wounds after cesarean delivery

BACKGROUND

Recent evidence suggests that locally delivered local anesthetics may exert tissue-damaging effects such as chondrolysis after intraarticular injection. Alteration of the inflammatory response is a potential mechanism for local anesthetic-induced tissue toxicity. In this study, we tested the effects of continuous local anesthetic infiltration on the release of inflammatory and nociceptive mediators in skin wounds after cesarean delivery.

METHODS

Thirty-eight healthy women undergoing cesarean delivery with spinal anesthesia were enrolled in this study, and were randomized to receive subcutaneous surgical wound infiltration with bupivacaine 5 mg/mL or saline at 2 mL/h for 24 hours after cesarean delivery. Wound exudate was sampled at 1, 3, 5, 7, and 24 hours after cesarean delivery using a subcutaneous wound drain technique. Cytokines, chemokines, substance P, prostaglandin E(2), and nerve growth factor were assayed using multiplex Bio-Plex® (Bio-Rad, Hercules, CA) and enzyme-linked immunosorbent assays.

RESULTS

Bupivacaine wound infusion resulted in a significant decrease of interleukin 10 and increase of substance P in wounds compared with saline infusion (area under the 24-hour concentration-time curve; P < 0.001). No statistically significant differences were detected for other cytokines, nerve growth factor, and prostaglandin E(2).

CONCLUSIONS

This study demonstrates that the continuous administration of clinically used doses of bupivacaine into wounds affects the local composition of wound mediators. Observed changes in interleukin 10 are compatible with a disruption of antiinflammatory mechanisms. Whether such modulation combined with the release of the proinflammatory mediator substance P results in an overall proinflammatory wound response will require future studies of wound healing.

Nitric oxide is negatively correlated to pain during acute inflammation

BACKGROUND

The role that nitric oxide (NO) plays in modulating pain in the periphery is unclear. We show here, the results of two independent clinical studies (microdialysis and gene expression studies) and a pilot dose finding study (glyceryl trinitrate study), to study the role of NO in the early phase of acute inflammatory pain following oral surgery. The effect of ketorolac on NO production and nitric oxide synthase (NOS) gene expression was also studied.

RESULTS

Microdialysis samples showed significantly higher levels of NO at the first 100 min compared to the last 80 minutes in the placebo treated group. In the ketorolac group, on the other hand, NO levels gradually decreased over the first 60 min but were similar to placebo over the later 100-180 min, with no significant change in NO level over time. The levels of NO were negatively correlated to pain intensity scores. Local infusion of the NO donor glyceryl trinitrate at the site of surgery, showed a small analgesic effect that did not reach statistical significance in the sample size used. While the gene expression of iNOS and eNOS were not up-regulated, 3 hours after surgery, nNOS was downregulated in both treatment groups and eNOS gene expression was significantly lower in the ketorolac group compared to the placebo group. Further, there was a positive correlation between the change in gene expression of nNOS and eNOS in the placebo group but not in the ketorolac group.

CONCLUSION

We suggest that at this early stage of inflammatory pain in man, NO is analgesic in the periphery. Further, ketorolac down-regulates eNOS gene expression.

Anti-inflammatory effects of intravenously administered lidocaine hydrochloride on ischemia-injured jejunum in horses

OBJECTIVE

To investigate effects of lidocaine hydrochloride administered IV on mucosal inflammation in ischemia-injured jejunum of horses treated with flunixin meglumine.

ANIMALS

24 horses.

PROCEDURES

Horses received saline (0.9% NaCl) solution (SS; 1 mL/50 kg, IV [1 dose]), flunixin meglumine (1 mg/kg, IV, q 12 h), lidocaine (bolus [1.3 mg/kg] and constant rate infusion [0.05 mg/kg/min], IV, during and after recovery from surgery), or both flunixin and lidocaine (n = 6/group). During surgery, blood flow was occluded for 2 hours in 2 sections of jejunum in each horse. Uninjured and ischemia-injured jejunal specimens were collected after the ischemic period and after euthanasia 18 hours later for histologic assessment and determination of cyclooxygenase (COX) expression (via western blot procedures). Plasma samples collected prior to (baseline) and 8 hours after the ischemic period were analyzed for prostanoid concentrations.

RESULTS

Immediately after the ischemic period, COX-2 expression in horses treated with lidocaine alone was significantly less than expression in horses treated with SS or flunixin alone. Eighteen hours after the ischemic period, mucosal neutrophil counts in horses treated with flunixin alone were significantly higher than counts in other treatment groups. Compared with baseline plasma concentrations, postischemia prostaglandin E(2) metabolite and thromboxane B(2) concentrations increased in horses treated with SS and in horses treated with SS or lidocaine alone, respectively.

CONCLUSIONS AND CLINICAL RELEVANCE

In horses with ischemia-injured jejunum, lidocaine administered IV reduced plasma prostaglandin E(2) metabolite concentration and mucosal COX-2 expression. Coadministration of lidocaine with flunixin ameliorated the flunixin-induced increase in mucosal neutrophil counts.

The effect of a peripheral block on inflammation-induced prostaglandin E2 and cyclooxygenase expression in rats

BACKGROUND

Peripheral inflammatory pain is associated with an upregulation of spinal cord COX-2 (cyclooxygenase-2), with a subsequent increase in central prostaglandin E2 (PGE2) levels associated with the development of hyperalgesia. In this study, we evaluated the effect of bupivacaine administered via a nerve block or via a systemic route on the spinal expression of PGE2 and COX in a model of peripheral inflammation in rats.

METHODS

All rats randomly received three injections: 1) a left subcutaneous hindpaw injection (0.2 mL with either carrageenan 2% w/v or saline), 2) a left sciatic block (0.2 mL with either bupivacaine 0.5% or saline), and 3) a systemic injection (subcutaneous interscapular with 0.2 mL with either bupivacaine 0.5% or saline). Local edema, thermal, and mechanical hyperalgesia as well as cerebrospinal fluid PGE2 concentration and COX-1 and COX-2 expression in the spinal cord in dorsal root ganglions were measured.

RESULTS

We confirmed that a bupivacaine block attenuates hyperalgesia and local inflammation in a model of inflammatory pain. This effect was associated with an inhibition of the increase in COX-2 expression induced by peripheral inflammation in dorsal root ganglions and cord. The subsequent production of PGE2 in cerebrospinal fluid was also impaired. Systemic bupivacaine did not modify either the hyperalgesia and local inflammation or COX expression.

CONCLUSION

These results constitute a key element strongly suggesting that local anesthetics act at a different level when administered systematically or via a nerve block.