Crystallization of Local Anesthetics When Mixed With Corticosteroid Solutions

A comparative evaluation of the effect of addition of 8 mg dexamethasone to 2% lignocaine with adrenaline in mandibular third molar surgery: a split mouth randomised double blind study

Background

Impacted lower third molar surgeries involve trauma in a highly vascularized zone with loose connective tissue leading to inflammatory sequelae including postoperative pain, swelling, trismus and generalised oral dysfunction during the post-operative phase. In minor oral surgical procedures, an all-inclusive method to protract anaesthesia and reduce the inevitable post-operative sequelae is yet to be explored substantially.

Aim

To evaluate the efficacy of dexamethasone added to local anaesthetics in extending the depth and duration of anaesthesia and decreasing the postoperative complications after surgical removal of impacted third molars.

Methodology

A controlled, randomized, split-mouth, double-blind prospective study involving lower third molar surgery was performed in 35 patients wherein the test group (Group I) received 8 mg dexamethasone added to 2 ml of 2% lignocaine with epinephrine and the control group (Group II) received 2 ml of sterile water added to 2 ml of 2% lignocaine with epinephrine. Onset and duration of anaesthesia were evaluated; followed by evaluation of pain, swelling and trismus for 7 days post-surgery, using independent t-test and ANOVA for repeated measures.

Results

Test group had a faster onset of anaesthesia by 69 s and a lengthier duration of 128.4 min (p < 0.001). Pain scores (Visual Analogue Scale) in the first 24 h were 4.9 and 7.5 in the test and control group respectively (p < 0.001). The average dosing of analgesics until postoperative day 7 in the test and control group were 12.6 and 18.4 respectively (p < 0.001). The swelling was significantly lesser in the test group, in addition, trismus was significantly lesser by 1 cm on postoperative days 1 and 2 and 0.2 cm on day 7.

Conclusion

The addition of dexamethasone to lignocaine in the nerve block reduces the time of onset and significantly prolongs the duration of anaesthesia with decreased pain, swelling and trismus. Steroids mixed directly with the local anaesthetic agent can minimise the post-operative sequelae associated with third molar surgery with a single needle prick.

Precipitation of sugammadex with nicardipine and labetalol: A laboratory research

There is a paucity of clinical data about whether sugammadex forms precipitates with other medications. This laboratory experimental study was performed to determine the drugs that produce precipitates with sugammadex. Samples of 1 ml of sugammadex were prepared in transparent cylinders, to which 1 ml of test drugs (rocuronium, neostigmine, glycopyrrolate, atropine, nitroglycerin, dobutamine, dopamine, epinephrine, vasopressin, norepinephrine, phenylephrine, ephedrine, esmolol, nicardipine, and labetalol) was added. The precipitation reaction was observed visually and via light microscope. The pH of each drugs before and after mixing with sugammadex was measured. White crystals were formed when sugammadex was mixed with nicardipine or labetalol. Sugammadex formed precipitate when mixed with nicardipine or labetalol. Sufficient fluid flushing is required between injections of each drug to prevent these reactions.

Buprenorphine has a concentration-dependent cytotoxic effect on equine chondrocytes in vitro

OBJECTIVE

To investigate the cytotoxic effects of 2 different concentrations of buprenorphine and compare them with bupivacaine and morphine on healthy equine chondrocytes in vitro.

SAMPLE

Primary cultured equine articular chondrocytes from 3 healthy adult horses.

PROCEDURES

Chondrocytes were exposed for 0 and 2 hours to the following treatments: media (CON; negative control); bupivacaine at 2.2 mg/mL (BUPI; positive control); morphine at 2.85 mg/mL (MOR); buprenorphine at 0.12 mg/mL (HBUPRE); or buprenorphine at 0.05 mg/mL (LBUPRE). Chondrocyte viability was assessed using live/dead staining, water-soluble tetrazolium salt-8 (WST-8) cytotoxic assay, LDH assay, and flow cytometry. All continuous variables were evaluated with a mixed ANOVA with treatment, time, and their interactions as the fixed effects and each horse as the random effect.

RESULTS

Buprenorphine showed a concentration-dependent chondrotoxic effect. The viability of chondrocytes was significantly decreased with exposure to HBUPRE and BUPI compared to CON, MOR, and LBUPRE.

CLINICAL RELEVANCE

Negligible chondrotoxic effects were observed in healthy cultured equine chondrocytes exposed to 0.05 mg/mL of buprenorphine, whereas higher concentrations (0.12 mg/mL) showed a marked cytotoxic effect. Based on these results, low concentrations of buprenorphine appear to be safe for intra-articular administration. Further evaluation of this dose in vivo is needed before recommending its clinical use.

Interaction between Dexamethasone, Ropivacaine, and Contrast Media Used in Interventional Pain Treatment: Considerations in Safety

Background and Objectives: Although epidural steroid injections are used as an effective treatment, this technique is associated with rare but serious ischemic complications, especially when particulate steroids are used. However, recent studies have reported that even if non-particulate steroids are used, particulates are formed by the interaction with some local anesthetics (LA), causing ischemic complications. This observational study evaluated commonly used combinations of non-particulate steroids and LA with contrast media via microscopic analysis and analyzed the chemical properties of each mixture to identify the correlation of particulate formation. Materials and Methods: Commonly used clinical non-particulate and particulate steroids, contrast media, and LA agent combinations were evaluated macroscopically and microscopically. The pH values were also measured at both room temperature (26 °C) and body temperature (36 °C). Where particulates were observed, the particulate size was measured. Results: Macroscopically, the mixture of non-particulate steroid and ropivacaine had a slightly cloudy appearance at all concentrations, but there was no visible particulate. However, when observed under a microscope, the pH-dependent particulate formation was observed at all concentration combinations tested. (0.1% ropivacaine: from 19 μm to 70 μm, and 0.2% ropivacaine: from 37 μm to 108 μm at room temperature (26 °C)). When contrast media was mixed or the temperature was raised to body temperature (36 °C), the number and size of the particulates decreased or dissolved. Conclusions: The combination of ropivacaine and dexamethasone, a non-particulate steroid, mainly used in epidural injections, forms particulates. However, when mixed with contrast media, particulates are dissolved because of changes in pH and factors affecting particulate formation. In fluoroscopy-guided injections, the use of contrast media could resolve particulate formation.

Crystallization of ropivacaine and bupivacaine when mixed with different adjuvants: a semiquantitative light microscopy analysis

INTRODUCTION

Amino-amide local anesthetics precipitate when mixed with some commonly used adjuvants, carrying the risk of perineural or vascular crystal deposition. The aim of this study was to evaluate whether crystallization occurs with routinely used local anesthetic-adjuvant combinations and if a relation with the solution's pH exists.

METHODS

All substances used in this trial were first visually investigated undiluted under tenfold magnification. Grade of crystallization was assessed using a 6 point grading system.Ropivacaine (0.2%, 0.75% and 1%) and bupivacaine (0.25% and 0.5%) were mixed in a 1:1 solution with the following adjuvants: dexamethasone, dexmedetomidine, clonidine, fentanyl, sodium bicarbonate 8.4% and sodium chloride 0.9%. Subsequently, ropivacaine (0.2% and 0.75%) and bupivacaine (0.25% and 0.5%) were mixed with adjuvants in concentrations commonly used in clinical practice and then serially assessed at several time points up to 1 hour. pH of all substances/combinations was assessed and correlated with crystallization grade.

RESULTS

All pure substances-except the reference standards sterile water and triamcinolon-showed crystallization grades ranging from grade 1 to grade 4. Addition of adjuvants lead to variable, unpredictable changes in crystal depositions. Addition of sodium bicarbonate 8.4% produced heavy crystallization in all combinations. Grade of crystallization was weakly positively related to the pH of the solution in 1:1 mixtures and clinically relevant concentrations, but not in pure substances.

DISCUSSION

Our study showed that crystallization is present in pure local anesthetics and may be increased or decreased by admixture of adjuvants. Higher pH of mixtures was weakly associated with more crystallization. Further research is necessary to translate these findings into clinical practice.

Neurologic Complication Due to Crystallization After Drug Interaction Between Alkalized Lidocaine and Ropivacaine: A Case Report and in vitro Study

Background

For pregnant women transferred to emergency cesarean section after receiving epidural labor analgesia, there is still a debate over the effective and safe means of rapidly delivering surgical anesthesia. Alkalized lidocaine is often adopted for fast onset time; however, crystallization of the anesthetic may cause severe neurologic symptoms.

Case Presentation

We report a case of a pregnant woman who underwent emergency cesarean section with satisfied analgesia but experienced severe weakness and paranaesthesia in the lower limb. After excluding lumbar disc herniation, obstetric nerve injury, and anesthesia technique causes by symptoms signs and magnetic resonance imaging, drug-related injury became the most likely cause. Our in vitro testing confirmed the obvious precipitation of additional anesthetic-concentrated ropivacaine (0.5–1%) with pretreated alkalized lidocaine. With trophic neurotherapy, the parturient attained prompt relief of weakness by day four, but delayed recovery of numbness, which lasted for 4 weeks.

Conclusion

To date, this is the first case reporting neurologic complication possibly due to drug crystallization in cesarean section. Our study confirmed the rapid onset of alkalized lidocaine and its safety to pretreated routine labor dose of ropivacaine (0.09%). However, additional anesthetic-concentrated ropivacaine (0.5–1%) to maintain the anesthesia and analgesia level is not suggested.

Evaluation of the in vitro effects of local anesthetics on equine chondrocytes and fibroblast-like synoviocytes

OBJECTIVE

To investigate the in vitro effects of clinically relevant concentrations of the local anesthetics (LAs) bupivacaine, lidocaine, lidocaine with preservative (LP), mepivacaine, and ropivacaine on equine chondrocyte and fibroblast-like synoviocyte (FLS) viability.

SAMPLES

Chondrocytes and FLSs of the metacarpophalangeal joints of 4 healthy adult horses.

PROCEDURES

Viability of chondrocytes and FLSs was determined with 3 assays: 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), lactate dehydrogenase (LDH), and trypan blue (TB) exclusion (only FLS). Viability was assessed after 30- and 60-minute exposures to 0.0625%, 0.125%, and 0.25% bupivacaine; 0.25%, 0.5%, and 1% lidocaine; 0.25%, 0.5%, and 1% LP; 0.25%, 0.5%, and 1% mepivacaine; and 0.125%, 0.25%, and 0.5% ropivacaine.

RESULTS

Viability of chondrocytes was significantly decreased with exposure to 0.25% bupivacaine, 1% lidocaine, 1% LP, 1% mepivacaine, and 0.25% ropivacaine. Viability of FLSs was significantly decreased with exposure to 0.25% bupivacaine, 1% mepivacaine, 1% LP, and 0.5% ropivacaine.

CONCLUSIONS AND CLINICAL RELEVANCE

Clinically relevant concentrations of LAs had in vitro time- and concentration-dependent cytotoxicity for chondrocytes and FLSs isolated from the metacarpophalangeal joints of healthy horses. Bupivacaine was more toxic to chondrocytes than lidocaine, mepivacaine, and ropivacaine, whereas bupivacaine, LP, mepivacaine, and ropivacaine were more toxic to FLSs than preservative-free lidocaine. Several LAs may negatively affect chondrocyte and FLS viability.

Non-Particulate Steroids (Betamethasone Sodium Phosphate, Dexamethasone Sodium Phosphate, and Dexamethasone Palmitate) Combined with Local Anesthetics (Ropivacaine, Levobupivacaine, Bupivacaine, and Lidocaine): A Potentially Unsafe Mixture

Purpose

Particulate steroids used in epidural steroid injections have been suspected as a cause of post-procedural embolic events. Some particulate steroids have been suspended only when the transforaminal approach is used for an epidural block of the spine. In contrast, non-particulate steroids are generally accepted for safety during epidural steroid injections. However, the safety of using a mixture of non-particulate steroids and local anesthetics is unknown. This study analyzed whether mixtures of commonly used non-particulate steroids and local anesthetics form crystals in solution.

Methods

We mixed non-particulate steroids (betamethasone sodium phosphate, dexamethasone sodium phosphate, and dexamethasone palmitate) and local anesthetics (ropivacaine, levobupivacaine, bupivacaine, and lidocaine) at different ratios. We used fluorescence microscopy to observe whether crystals formed in mixed solutions; we also measured the pH of each steroid, local anesthetic, and the mixtures.

Results

Ropivacaine or levobupivacaine and betamethasone sodium phosphate produced large crystals (>50 µm). Ropivacaine or levobupivacaine and dexamethasone sodium phosphate produced small crystals (<10 µm). Lidocaine and all non-particulate steroids produced no identifiable crystals; dexamethasone palmitate and all local anesthetics did not form significant particulates. Betamethasone sodium phosphate and dexamethasone sodium phosphate demonstrated basic pH, while all local anesthetics demonstrated acidic pH. Mixtures showed a wide pH range.

Conclusion

Non-particulate steroids can form crystals upon combination with local anesthetics. Crystal formation may be caused by alkalinization of steroids. The mixing of ropivacaine or levobupivacaine and betamethasone sodium phosphate may require caution during an epidural steroid injection. Lidocaine or bupivacaine is recommended as a local anesthetic. Dexamethasone palmitate is a candidate for a mixture, but additional studies on its safety and effectiveness are needed.

Effect of intravenous dexamethasone on the duration of postoperative analgesia for popliteal sciatic nerve block: a randomized, double-blind, placebo-controlled study

Background

Intravenous (IV) dexamethasone prolongs the duration of a peripheral nerve block; however, there is little available information about its optimal effective dose. This study aimed to evaluate the effects of three different doses of IV dexamethasone on the duration of postoperative analgesia to determine the optimal effective dose for a sciatic nerve block.

Methods

Patients scheduled for foot and ankle surgery were randomly assigned to receive normal saline or IV dexamethasone (2.5 mg, 5 mg, or 10 mg). An ultrasound-guided popliteal sciatic nerve block was performed using 0.75% ropivacaine (20 ml) before general anesthesia. The duration of postoperative analgesia was the primary outcome, and pain scores, use of rescue analgesia, onset time, adverse effects, and patient satisfaction were assessed as secondary outcomes.

Results

Compared with the control group, the postoperative analgesic duration of the sciatic nerve block was prolonged in groups receiving IV dexamethasone 10 mg (P < 0.001), but not in the groups receiving IV dexamethasone 2.5 mg or 5 mg. The use of rescue analgesics was significantly different among the four groups 24 h postoperatively (P = 0.001) and similar thereafter. However, pain scores were not significantly different among the four groups 24 h postoperatively. There were no statistically significant differences in the other secondary outcomes among the four groups.

Conclusions

This study demonstrated that compared to the controls, only IV dexamethasone 10 mg increased the duration of postoperative analgesia following a sciatic nerve block for foot and ankle surgery without the occurrence of adverse events.

Analgesic Effect of the Topical Use of Dexamethasone in Ultrasound-Guided Axillary Brachial Plexus Blockade: A Prospective, Randomized, Double-Blind, Placebo-Controlled Study

Introduction

Increasing the duration of regional anesthesia in orthopedic surgery is of vital importance, as it prolongs postoperative analgesia, allowing faster rehabilitation of patients. Dexamethasone has been found to extend the block duration in animal and human studies. The aim of this study is the assessment of the effect of the addition of dexamethasone to ropivacaine on the onset and duration of axillary brachial plexus block, along with the intensity of postoperative pain.

Methods

Forty patients undergoing below-elbow surgery under ultrasound-guided axillary brachial plexus block were randomly allocated to receive either 30 mL ropivacaine 0.75% with 2 mL of saline (Group A, n = 20) or 30 mL ropivacaine 0.75% with 2 mL of dexamethasone (4 mg) (Group B, n = 20). Sensory and motor blockade were assessed, with the use of the pinprick test and the modified Bromage scale, at five, 10, 15, and 20 min after the block. The duration of analgesia, intensity of postoperative pain, postoperative opioid consumption, overall satisfaction, and perioperative complications were compared between the two groups.

Results

We found no difference at the mean onset time of the sensory and motor block between the two groups. The mean duration of postoperative analgesia was three hours higher in the dexamethasone group (15.85 ± 4.82 versus 11.75 ± 6.81, p-value = 0.035). Pain intensity was lower in the dexamethasone group, at six and 12 hours after surgery (3.45 ± 1.79 versus 4.65 ± 1.79, p-value = 0.040). Postoperative opioid consumption, patient overall satisfaction, and perioperative complications were not significantly different between groups.

Conclusions

Dexamethasone prolongs the duration of ropivacaine in an axillary brachial plexus block and decreases postoperative pain in patients subjected to below-elbow surgery.

Safety of epidural steroids: a review

Spine disease is one of the most common musculoskeletal diseases, especially in an aging society. An epidural steroid injection (ESI) is a highly effective treatment that can be used to bridge the gap between physical therapy and surgery. Recently, it has been increasingly used clinically. The purpose of this article is to review the complications of corticosteroids administered epidurally. Common complications include: hypothalamic-pituitary-adrenal (HPA) axis suppression, adrenal insufficiency, iatrogenic Cushing's syndrome, hyperglycemia, osteoporosis, and immunological or infectious diseases. Other less common complications include psychiatric problems and ocular ailments. However, the incidence of complications related to epidural steroids is not high, and most of them are not serious. The use of nonparticulate steroids is recommended to minimize the complications associated with epidural steroids. The appropriate interval and dosage of ESI are disputed. We recommend that the selection of appropriate ESI protocol should be based on the suppression of HPA axis, which reflects the systemic absorption of the corticosteroid.

Intravenous patient-controlled analgesia: in vitro stability profiles of mixtures containing fentanyl, hydromorphone, oxycodone, nefopam, ondansetron, and ramosetron

Background and objectives

Patient-controlled analgesia often involves combinations of multiple drugs. This study aimed to determine the stability of drug mixtures commonly used for intravenous patient-controlled analgesia.

Materials and methods

We examined four of the most commonly used drug combinations in intravenous patient-controlled analgesia at our institution. Mixtures contained fentanyl (400 μg), either oxycodone (10 mg) or hydromorphone (4 mg), nefopam (20 mg), and either ondansetron (10 mg) or ramosetron (0.3 mg). Each drug mixture was diluted in 0.9% saline and stored in a portable patient-controlled analgesia system at room temperature (24 °C) for 96 h. Physical attributes including color, turbidity, and precipitation were assessed using digital imaging and optical microscopy. Sterility testing was conducted to assess for microbiological contamination. The pH of each mixture was monitored for up to 96 h after mixing. The concentration of each drug in the mixture was also evaluated using high-performance liquid chromatography.

Results

All mixtures remained colorless and transparent with no visible sediment for 96 h. After 14 days of culture, none of the samples showed bacterial or fungal growth. The pH for all mixtures was maintained between 4.17 and 5.19, and the mean pH change in any mixture was less than 0.4 over the study period. The concentration of each drug remained between 90 and 110% of the initial value for 96 h after mixing.

Conclusion

Four drug mixtures commonly used for intravenous patient-controlled analgesia are physiochemically stable and remain sterile for 96 h after mixing.

The Simplified Science of Corticosteroids for Clinicians

Clinicians should be aware of the differences in corticosteroid formulations as these differences dictate which agent is best in various clinical situations. Corticosteroids work primarily by modulating transcriptional, post-transcriptional, and post-translational mechanisms within cellular nuclei to decrease the production of inflammatory mediators. Because this process requires change at the cellular level, clinical effects typically take days. The main consideration when selecting a corticosteroid is solubility. Less-soluble agents have a longer onset of action and a longer duration. However, they can have negative side effects on soft-tissue structures. They are ideal for intra-articular use. More-soluble agents have a faster onset of action but are rapidly cleared. They are ideal for extra-articular soft-tissue structures. Fluorinated compounds have decreased solubility, which further increases duration of action, but they have been shown to be associated with tendon rupture and atrophy.

Are patients more likely to have hip osteoarthritis progression and femoral head collapse after hip steroid/anesthetic injections? A retrospective observational study

OBJECTIVE

To evaluate progression of osteoarthritis and femoral head articular surface collapse in hip steroid/anesthetic injection patients (HIPs).

MATERIALS AND METHODS

This study was IRB-approved and HIPAA-compliant. Two musculoskeletal radiologists performed retrospective, blinded reviews of radiography for 70 HIPs (40 mg triamcinolone/4 mL 0.5% preservative-free ropivacaine) with a 3- to 10-month follow-up and two control groups: demographic-matched patients with similar hip radiograph follow-up duration but no injection; and glenohumeral joint injection patients. Discordant evaluations were adjudicated by a third, senior reader. Groups were compared using Fisher's exact and unpaired t tests.

RESULTS

There were 70 HIPs (mean age 67 ± 17 (range 19-92) years; 44 women, 26 men), who were followed for a mean of 6 ± 2 (3-12) months. Thirty-one (31 out of 70, 44%) of HIPs had progression of osteoarthritis after injection, versus 17 out of 70 (24%) of hip controls (HCs) and 13 out of 44 (30%) of glenohumeral injection patients (GIPs). This difference between HIPs and HCs was statistically significant (p = 0.02) but not that between HIPs and GIPs (0.17). Twelve (12 out of 70, 17%) HIPs had new collapse, compared with 1 out of 70 (1%) of HCs and 1 out of 44 (2%) of GIPs. This difference was statistically significant (HCs: p = 0.002; GIPs: p = 0.02).

CONCLUSION

Hip steroid/anesthetic injection patients are more likely to demonstrate osteoarthritis progression and femoral head collapse than HC and GIPs in the injected joint 3-12 months after steroid and anesthetic injection. Further evaluation of hip injectates and the injection population is warranted.

Intra-articular Corticosteroid Injections for Symptomatic Knee Osteoarthritis: What the Orthopaedic Provider Needs to Know

Intra-articular corticosteroid injections have been used for decades in the management of symptomatic osteoarthritis of the knee and remain a common practice. The pain relief from a steroid injection is thought to work by reducing inflammation within the arthritic knee. Substantial variability remains among providers with regard to the technique used to perform the procedure, including the site of the injection, the medications injected, and the level of sterility. The success of steroid injections in relieving arthritic knee pain most often occurs in the short term. However, the efficacy of intra-articular corticosteroid injections varies within the published literature. The latest American Academy of Orthopaedic Surgeons clinical practice guideline does not support conclusive recommendations about the use of intra-articular corticosteroid injections for symptomatic knee osteoarthritis. Providers should be aware of the adverse effects and potential complications of these injections when using them in clinical practice.

Dilution and microfiltration of particulate corticosteroids for spinal epidural injections: impact on drug concentration and agglomerate formation

Particulate corticosteroids have been described to lead to greater pain improvement compared with their non-particulate counterparts when used in epidural injections. It is hypothesised that filtering may significantly impact their concentration and long-term efficacy. We investigated if passing particulate suspensions through different commonly-used filters affects drug dosage. Two particulate corticosteroid formulations, triamcinolone acetonide and methylprednisolone acetate, were mixed at different concentrations with either bupivacaine hydrochloride or 0.9% sodium chloride. Solutions were passed through a 5-μm and a 0.2-μm filter. Mass spectroscopy results indicated a complete loss of corticosteroid from the solutions using both filters, and light microscopy imaging demonstrated agglomerate formation, suggesting that filtering interferes with drug dosage. The choice of diluents must also be considered to reduce large agglomerate formation. Clinicians should be aware of the consequences of filtering particulate suspensions and carefully consider the selection of diluent when considering treatment plans.

Trends in steroid agent and diluent choices for epidural steroid injections: a survey of Spine Intervention Society physicians

BACKGROUND

Epidural steroid injections (ESIs) are a frequently used treatment for refractory radicular spinal pain. ESIs, particularly transforaminal epidural steroid injections (TFESI), may provide pain relief and delay the need for surgery. Corticosteroid agent and diluent choices are known to impact the safety of ESIs. In particular, the risk of embolization with particulate corticosteroids has led to recommendations for non-particulate steroid use by the Multisociety Pain Workgroup. Additionally, there is in vitro evidence that ropivacaine can crystalize in the presence of dexamethasone, potentially creating a particulate-like injectate. Despite widespread use and known risk mitigation strategies, current practice trends related to steroid and diluent choices are unknown.

OBJECTIVE

Identify the use of particulate versus non-particulate corticosteroids for epidural steroid injections in the cervical and lumbar spine, as well as local anesthetics commonly used as diluents during these procedures.

METHODS

Cross-sectional survey study of 314 physician members of the Spine Interventional Society.

RESULTS

41% and 9% of providers reported using particulate corticosteroids during lumbar TFESIs and cervical TFESI, respectively. Four per cent of providers reported the use of ropivacaine in cervical TFESIs. Forty-four per cent of respondents reported using anesthetic in cervical interlaminar ESIs. 21% of providers report using high volumes (> 4.5 mL) during cervical interlaminar ESIs.

CONCLUSION

Current trends, as assessed by this survey study, indicate substantial variability in steroid and diluent choice for ESIs. Patterns were identified that may impact patient safety including the continued use of particulate corticosteroids for TFESIs and the use of ropivacaine during TFESIs by a subset of respondents.

Clinical effectiveness of single dose of intravenous dexamethasone on the duration of ropivacaine axillary brachial plexus block: the randomized placebo-controlled ADEXA trial

Background and objectives

The effect of intravenous dexamethasone on the duration of axillary plexus block performed using ropivacaine is not described. The aim of this study is to assess the effect of intravenous dexamethasone on the duration of axillary plexus block analgesia after distal upper arm surgery.

Methods

In this prospective, randomized, placebo-controlled, double-blinded trial, consenting patients scheduled for hand or forearm surgery under ultrasound-guided axillary plexus block performed using 0.5 mL/kg of 0.475% ropivacaine, were randomized to receive an intravenous injection of either 8 mg/2 mL of dexamethasone (Dexa group) or 2 mL of saline (Control). The primary outcome was the time of first analgesic intake after axillary block. Secondary outcomes included motor or sensory block duration, total use of postoperative analgesics, and block-related complications.

Results

Among the 98 patients included, 6 and 2 patients did not require postoperative analgesic intake in Dexa and Control groups, respectively (p=0.06). The time of first analgesic intake was significantly longer in the Dexa (20.9±9.3 hours) than in the Control group (14.7±6.6 hours, p<0.0004). Motor and sensory recovery occurred significantly later, and total analgesic consumption was lower in the Dexa than in the Control group. No nerve complication related to intravenous dexamethasone injection was recorded.

Conclusions

This study showed that intravenous dexamethasone delayed for 6 hours the time to first analgesic intake after upper arm surgery under axillary plexus block performed with the long-lasting local anesthetic ropivacaine. This suggests that intravenous dexamethasone could be an interesting adjuvant to axillary plexus block.

Trial registration number

NCT02862327

Perineural versus intravenous dexamethasone as an adjuvant in regional anesthesia: a systematic review and meta-analysis

Background

Dexamethasone is a common adjuvant for local anesthetics in regional anesthesia, but the optimal route of administration is controversial. Therefore, we did a systematic review and meta-analysis of randomized controlled trials to assess the effect of perineural versus intravenous dexamethasone on local anesthetic regional nerve-blockade outcomes.

Materials and methods

Medline (through PubMed), Embase, Cochrane, Web of Science, and Biosis Previews databases were systematically searched (published from inception of each database to January 1, 2017) to identify randomized controlled trials. The data of the selected trials were statistically analyzed to find any significant differences between the two modalities. The primary outcome was the duration of analgesia. Secondary outcomes included duration of motor block, postoperative nausea and vomiting, and postoperative analgesic dose at 24 hours. We conducted a planned subgroup analysis to compare the effects between adding epinephrine or not.

Results

Ten randomized controlled trials met the inclusion criteria of our analysis, with a total of 749 patients. Without the addition of epinephrine, the effects of perineural and intravenous dexamethasone were equivalent concerning the duration of analgesia (mean difference 0.03 hours, 95% CI –0.17 to 0.24). However, with the addition of epinephrine, the analgesic duration of perineural dexamethasone versus intravenous dexamethasone was prolonged (mean difference 3.96 hours, 95% CI 2.66–5.27). Likewise, the impact of epinephrine was the same on the duration of motor block. The two routes of administration did not show any significant differences in the incidence of postoperative nausea and vomiting, nor on postoperative analgesic consumption at 24 hours.

Conclusion

Our results show that perineural dexamethasone can prolong the effects of analgesic duration when compared to the intravenous route, only when epinephrine is coadministered. Without epinephrine, the two modalities show equivalent effect as adjuvants on regional anesthesia.

Delayed onset paraparesis complicating epidural steroid injection with underlying spinal dural arteriovenous fistula

We report a case of a 48-year-old man with chronic back pain attributed to discogenic lumbar radiculopathy who underwent a fluoroscopy-guided L2-3 interlaminar epidural steroid injection. 4 h later, he developed acute paraparesis, sensory loss below T10 level and urinary retention. MRI of the thoracic spine revealed diffuse abnormal T2/FLAIR signal and extensive vascular flow voids. A spinal dural arteriovenous fistula was confirmed on spinal angiography. Embolization of the spinal dural arteriovenous fistula resulted in significant improvement of symptoms. We review previously reported cases and current understanding of the pathophysiology of this complication. All cases had symptom onset several hours after the procedure. There seems to be a trend toward better outcomes with earlier treatment.