Pharmacological and clinical implications of local anaesthetic mixtures: a narrative review.

Various techniques have been explored to prolong the duration and improve the efficacy of local anaesthetic nerve blocks. Some of these involve mixing local anaesthetics or adding adjuncts. We did a literature review of studies published between 01 May 2011 and 01 May 2021 that studied specific combinations of local anaesthetics and adjuncts. The rationale behind mixing long- and short-acting local anaesthetics to hasten onset and extend duration is flawed on pharmacokinetic principles. Most local anaesthetic adjuncts are not licensed for use in this manner and the consequences of untested admixtures and adjuncts range from making the solution ineffective to potential harm. Pharmaceutical compatibility needs to be established before administration. The compatibility of drugs from the same class cannot be inferred and each admixture requires individual review. Precipitation on mixing (steroids, non-steroidal anti-inflammatory drugs) and subsequent embolisation can lead to serious adverse events, although these are rare. The additive itself or its preservative can have neurotoxic (adrenaline, midazolam) and/or chondrotoxic properties (non-steroidal anti-inflammatory drugs). The prolongation of block may occur at the expense of motor block quality (ketamine) or block onset (magnesium). Adverse effects for some adjuncts appear to be dose-dependent and recommendations concerning optimal dosing are lacking. An important confounding factor is whether studies used systemic administration of the adjunct as a control to accurately identify an additional benefit of perineural administration. The challenge of how best to prolong block duration while minimising adverse events remains a topic of interest with further research required.

Prospective Evaluation of a Standardized Opioid Reduction Protocol after Anorectal Surgery.

BACKGROUND: Surgery for anorectal disease is thought to cause significant postoperative pain. Our previous work demonstrated that most opioids prescribed after anorectal surgery are not used. We aimed to evaluate a standardized protocol for pain control after anorectal surgery. METHODS: We prospectively evaluated a standardized opioid reduction protocol over a 13-mo period for all patients undergoing elective anorectal surgery at our institution. Protocol components include preoperative query, procedural local-anesthetic blocks, first-line nonopioid analgesic use ± opioid prescription of five pills, and standardized postoperative instructions. Patients completed questionnaires at postoperative follow-up. Patients with history of opioid abuse or use within 30 d of operation, loss to follow-up, or surgical complications were excluded. Primary outcome was quality of pain control on a five-point scale. Secondary outcomes included use of nonopioid analgesics, opioids used, and need for refill. RESULTS: A total of 55 patients were included. Mean age was 47 ± 17 y with 23 women (42%). Anorectal abscess/fistula procedures were the most common (69%) followed by pilonidal procedures (11%) and hemorrhoidectomy (7%). Most had general anesthesia (60%) with the remainder local anesthesia ± sedation. Fifty-four (98%) had procedural local-anesthetic blocks. Twenty-six patients (47%) were prescribed opioids with a median of five pills. Forty-seven patients (85%) reported the use of nonopioid analgesics. Forty-six patients (84%) reported excellent to very good pain control. About 220 opioid pills were prescribed, and 122 were reported to be used. One patient (2%) received an opioid refill. CONCLUSIONS: Satisfactory pain control after anorectal surgery can be achieved with multimodality therapy with little to no opioid use for most patients.

Infiltrative local anesthesia with articaine is equally as effective as inferior alveolar nerve block with lidocaine for the removal of erupted molars.

AIM: The aim of this study is to assess the efficacy of 4% articaine with 1:100,000 adrenaline given as buccal and lingual infiltration in adult patients undergoing erupted mandibular first and second molar teeth extraction versus inferior alveolar nerve block technique using 2% lignocaine with 1:80,000 adrenaline. MATERIALS AND METHODS: A total of 100 patients undergoing extraction of mandibular posterior teeth were divided into two equally matched groups for the study, out of which 50 patients were given 4% articaine with 1:100,000 adrenaline as buccal and lingual infiltration and 50 patients were given 2% lignocaine with 1:80,000 adrenaline using classic direct inferior alveolar nerve block with lingual and buccal nerve block. Efficacy of anesthesia was determined using a numeric analog scale (NAS) ranging from 0 indicating no pain to 10 indicating the worst pain imaginable. The NAS was taken by a different operator to avoid bias. RESULTS: The pain scores in both groups were analyzed using the Mann-Whitney U test, and a p value of 0.338 was obtained which is not statistically significant. Hence, no significant difference in the pain score was established between both groups. The adverse effects of both the local anesthetics if any were noted. CONCLUSION: From this study, we concluded that the use of 4% articaine with 1:100,000 adrenaline is as effective as inferior alveolar nerve block with lignocaine but without the risk of attendant adverse effects of inferior alveolar nerve block technique.

Which one is more effective for analgesia in infratentorial craniotomy? The scalp block or local anesthetic infiltration.

OBJECTIVES: The most painful stages of craniotomy are the placement of the pin head holder and the skin incision. The primary aim of the present study is to compare the effects of the scalp block and the local anesthetic infiltration with bupivacaine 0.5% on the hemodynamic response during the pin head holder application and the skin incision in infratentorial craniotomies. The secondary aims are the effects on pain scores and morphine consumption during the postoperative 24h. METHODS: This prospective, randomized and placebo controlled study included forty seven patients (ASA I, II and III). The scalp block was performed in the Group S, the local anesthetic infiltration was performed in the Group I and the control group (Group C) only received remifentanil as an analgesic during the intraoperative period. The hemodynamic response to the pin head holder application and the skin incision, as well as postoperative pain intensity, cumulative morphine consumption and opioid related side effects were compared. RESULTS: The scalp block reduced the hemodynamic response to the pin head holder application and the skin incision in infratentorial craniotomies. The local anesthetic infiltration reduced the hemodynamic response to the skin incision. As well as both scalp block and local anesthetic infiltration reduced the cumulative morphine consumption in postoperative 24h. Moreover, the pain intensity was lower after scalp block in the early postoperative period. CONCLUSION: The scalp block may provide better analgesia in infratentorial craniotomies than local anesthetic infiltration.

Combined femoral and sciatic nerve block versus femoral and local infiltration anesthesia for pain control after total knee arthroplasty: a meta-analysis of randomized controlled trials.

BACKGROUND: The purpose of this systematic review and meta-analysis of randomized controlled trials (RCTs) was to evaluate the effect of combined femoral and sciatic nerve block (SNB) versus femoral and local infiltration anesthesia (LIA) after total knee arthroplasty (TKA). METHODS: The electronic databases PubMed, Embase, Cochrane Library, and Web of Science were searched from their inception to 15 June 2016. Articles comparing combined femoral and SNB versus femoral and LIA for pain control were eligible for this meta-analysis. This systematic review and meta-analysis was performed according to the PRISMA statement criteria. The primary endpoint was the visual analogue scale (VAS) score with rest at 12, 24, and 48 h, which represents the pain control after TKA. Data regarding active knee flexion, length of hospital stay, anesthesia time, and morphine use at 24 and 48 h were also compiled. The complications of postoperative nausea and vomiting (PONV) and fall were also noted to assess the safety of morphine-sparing effects. After testing for publication bias and heterogeneity across studies, the data were aggregated for random-effects modeling when necessary. RESULTS: Seven clinical trials with 615 patients were included in the meta-analysis. The pooled results indicated that SNB was associated with a lower VAS score at 12 h (MD = -6.96; 95% CI -8.36 to -5.56; P < 0.001) and 48 h (MD = -2.41; 95% CI -3.90 to -0.91; P < 0.001) after TKA. There was no significant difference between the SNB group and the LIA group in terms of the VAS score at 24 h (MD = 0.67; 95% CI -0.31 to 1.66; P = 0.182). The anesthesia time in the LIA group was shorter than in the SNB group, and the difference was statistically significant (MD = 4.31, 95% CI 1.34 to 7.28, P = 0.004). There were no significant differences between the groups in terms of active knee flexion, length of hospital stay, morphine use, PONV, and the occurrence of falls. CONCLUSIONS: SNB may provide earlier anesthesia effects than LIA when combined femoral nerve block (FNB); however, there were no differences in morphine use, active knee flexion, and PONV between the groups. The LIA group spent less time under anesthesia, suggesting that LIA may offer a practical and potentially safer alternative to SNB.

Failure rate of inferior alveolar nerve block among dental students and interns.

OBJECTIVES: To report the failure rate of inferior alveolar nerve block (IANB) among dental students and interns, causes of failure, investigate awareness of different IANB techniques, and to report IANB-associated complications.   METHODS: A 3-page questionnaire containing 13 questions was distributed to a random sample of 350 third to fifth years students and interns at the College of Dentistry, King Saud University, Riyadh, Saudi Arabia on January 2011. It included demographic questions (age, gender, and academic level) and questions on IANB failure frequency and reasons, actions taken to overcome the failure, and awareness of different anesthetic techniques, supplementary techniques, and complications.   RESULTS: Of the 250 distributed questionnaires, 238 were returned (68% response rate). Most (85.7%) of surveyed sample had experienced IANB failure once or twice. The participants attributed the failures most commonly (66.45%) to anatomical variations. The most common alternative technique used was intraligamentary injection (57.1%), although 42.8% of the sample never attempted any alternatives. Large portion of the samples stated that they either lacked both knowledge of and training for other techniques (44.9%), or that they had knowledge of them but not enough training to perform them (45.8%).  CONCLUSION: To  decrease IANB failure rates for dental students and interns, knowledge of landmarks, anatomical variation and their training in alternatives to IANB, such as the Gow-Gates and Akinosi techniques, both theoretically and clinically in the dental curriculum should be enhanced.

Trigger point injections for headache disorders: expert consensus methodology and narrative review.

OBJECTIVE/BACKGROUND: To review the existing literature and describe a standardized methodology by expert consensus for the performance of trigger point injections (TPIs) in the treatment of headache disorders. Despite their widespread use, the efficacy, safety, and methodology of TPIs have not been reviewed specifically for headache disorders by expert consensus. METHODS: The Peripheral Nerve Blocks and Other Interventional Procedures Special Interest Section of the American Headache Society over a series of meetings reached a consensus for nomenclature, indications, contraindications, precautions, procedural details, outcomes, and adverse effects for the use of TPIs for headache disorders. A subcommittee of the Section also reviewed the literature. RESULTS: Indications for TPIs may include many types of episodic and chronic primary and secondary headache disorders, with the presence of active trigger points (TPs) on physical examination. Contraindications may include infection, a local open skull defect, or an anesthetic allergy, and precautions are necessary in the setting of anticoagulant use, pregnancy, and obesity with unclear anatomical landmarks. The most common muscles selected for TPIs include the trapezius, sternocleidomastoid, and temporalis, with bupivacaine and lidocaine the agents used most frequently. Adverse effects are typically mild with careful patient and procedural selection, though pneumothorax and other serious adverse events have been infrequently reported. CONCLUSIONS: When performed in the appropriate setting and with the proper expertise, TPIs seem to have a role in the adjunctive treatment of the most common headache disorders. We hope our effort to characterize the methodology of TPIs by expert opinion in the context of published data motivates the performance of evidence-based and standardized treatment protocols.

Guideline update for the performance of fusion procedures for degenerative disease of the lumbar spine. Part 13: injection therapies, low-back pain, and lumbar fusion.

The medical literature continues to fail to support the use of lumbar epidural injections for long-term relief of chronic back pain without radiculopathy. There is limited support for the use of lumbar epidural injections for shortterm relief in selected patients with chronic back pain. Lumbar intraarticular facet injections are not recommended for the treatment of chronic lower-back pain. The literature does suggest the use of lumbar medial nerve blocks for short-term relief of facet-mediated chronic lower-back pain without radiculopathy. Lumbar medial nerve ablation is suggested for 3-6 months of relief for chronic lower-back pain without radiculopathy. Diagnostic medial nerve blocks by the double-injection technique with an 80% improvement threshold are an option to predict a favorable response to medial nerve ablation for facet-mediated chronic lower-back pain without radiculopathy, but there is no evidence to support the use of diagnostic medial nerve blocks to predict the outcomes in these same patients with lumbar fusion. There is insufficient evidence to support or refute the use of trigger point injections for chronic lowerback pain without radiculopathy.

REGIONAL ANALGESIA FOR POST-OPERATIVE PAIN MANAGEMENT--INITIAL EXPERIENCE IN A LOW RESOURCE SETTING.

OBJECTIVE: The aim of this study is to demonstrate the use of some regional anaesthetic techniques in effective postoperative pain control in a low resource setting. We also wanted to find out the potential benefits and prospects of regional techniques to achieve effective postoperative analgesia. DESIGN: This study was a prospective observational study in which 25 patients presenting for various orthopaedic and general surgical procedures were recruited randomly. SETTING: Ahmadu Bello University Teaching Hospital (ABUTH), Zaria, Nigeria from December, 2008 to May, 2009. SUBJECTS: Eligible patients were males and females aged 21-55 years. These included emergency and elective cases. RESULTS: The age range was 21-55 years with a mean age of 34 years. Of the 25 patient studied, 14 of them were men and 11 women constituting 56% and 44% respectively. Our study shows that Hausa/Fulani ethnic group made up 75% of the study population. Intraoperatively, the anaesthetic techniques used were general anaesthesia (only) in 13 patients (52%), Regional techniques consisting of spinals, epidurals, combined spinals and epidurals and brachial plexus blocks in nine patients (36%) and three (12%) of the patients had a combination of general anaesthesia (GA) and regional anaesthesia (RA). For post-operative pain management, nine patients (36%) had continuous brachial plexus block using intermittent injections, 13 (52%) patients had epidural catheters with intermittent top-up injections and three (12%) patients received combined spinal and epidural with an epidural catheter left in-situ for intermittent top-ups. The drugs used for top-ups included 0.125% plain bupivacaine (15 patients), 0.125% plain bupivacaine + 2.5 mcgs/ml Fentanyl (10 patients) in 10 ml aliquots. The outcome was good in most patients with 19 patients (82.4%) experiencing only mild pain (numeric pain score 0-3). Onset of post-operative pain was 13-18 hours in most (52%) of patients with majority of patients (80%) requiring only a single dose of opioid in 24 hours. There was no incidence of infection at site of catheter insertion one week after the procedure. CONCLUSION: Regional techniques if used properly can provide superior pain control in the post-operative period. There is reduction in the requirements of opioids in the immediate post-operative when regional techniques are used for pain management. We need to encourage the use of these techniques especially in our setting where resources are sparse and potent analgesics are not always available.

Testing rocuronium-induced neuromuscular blockade at the stapedius muscle using stapedius reflex measurements.

BACKGROUND: Neuromuscular monitoring prior to emergence from anaesthesia has been shown to be necessary to achieve adequate airway protection in order to decrease postoperative pulmonary complications. In the present study we hypothesized that stapedius reflex measurement allows the detection of residual neuromuscular blockade using the stapedius muscle following the administration of rocuronium. PATIENTS AND METHODS: Parallel stapedius and acceleromyographic measurements were performed on 20 patients undergoing cholecystectomy. Acceleromyographic measurements were continuously performed during the course of anaesthesia, whereas the stapedius reflex was measured on different occasions: (1) after premedication but before anaesthesia induction, (2) after induction, but before administration of muscle relaxant, (3) after administration of muscle relaxant, (4) during the course of surgical anaesthesia at regular intervals, and (5) continuously performed during emergence from anaesthesia, until the stapedius reflex threshold returned to normal. RESULTS: The intensity of the sound energy at which the stapedius reflex is detectable was similar: 89.5 ± 9.9 dB(mean ± SD) after premedication and after anaesthetic induction. However, after administration of rocuronium, when the twitch height decreased to 5%, the stapedius reflex disappeared, indicating a total block of the stapedius muscle.During the recovery phase (twitch>10%) significantly higher sound energies compared to baseline values were necessary to evoke the reflex, indicating residual inhibition of the stapedius muscle. At the point where stapedius reflex threshold returned to normal the twitch height averaged about 50% showing low sensitivity of the tympanometry in detecting residual neuromuscular blockade. CONCLUSIONS: The neuromuscular effect of rocuronium on the stapedius muscle can be detected using stapedius reflex measurements. Due to its methodological limitation and low sensitivity, the method cannot be recommended for the monitoring of residual neuromuscular blockade.

Evidence basis for ultrasound-guided block characteristics: onset, quality, and duration.

BACKGROUND AND OBJECTIVES: This systematic review summarizes existing evidence for superior onset, quality, and duration of block for ultrasound (US) guidance versus other techniques for nerve localization. METHODS: MEDLINE was systematically searched from 1966 to September 2009 for randomized controlled trials (RCTs) comparing US guidance to another technique for peripheral nerve blocks. RESULTS: Sixteen RCTs were identified for upper-extremity peripheral nerve blocks and 8 for lower extremity. Jadad scores for quality of RCT ranged from 1 to 5, with a median of 2. For upper-extremity blocks, 9 (60%) of 15 RCTs reported faster onset of block, 4 (25%) of 16 reported better quality of block, and 1 (17%) of 6 reported longer duration of block with US. Only 1 RCT reported that US was inferior in any outcome. For lower-extremity blocks, 5 (71%) of 7 RCTs reported faster onset, 5 (63%) of 8 reported better quality, and none of 3 RCTs reported longer duration of blocks. No RCTs reported that US was inferior in any outcome. CONCLUSIONS: There is level 1b evidence to make a grade A recommendation that US guidance provides a modest improvement in block onset and quality of peripheral nerve blocks. Ultrasound is rarely inferior to other techniques.

Regional anesthesia in the patient receiving antithrombotic or thrombolytic therapy: American Society of Regional Anesthesia and Pain Medicine Evidence-Based Guidelines (Third Edition).

The actual incidence of neurologic dysfunction resulting from hemorrhagic complications associated with neuraxial blockade is unknown. Although the incidence cited in the literature is estimated to be less than 1 in 150,000 epidural and less than 1 in 220,000 spinal anesthetics, recent epidemiologic surveys suggest that the frequency is increasing and may be as high as 1 in 3000 in some patient populations.Overall, the risk of clinically significant bleeding increase with age,associated abnormalities of the spinal cord or vertebral column, the presence of an underlying coagulopathy, difficulty during needle placement,and an indwelling neuraxial catheter during sustained anticoagulation( particularly with standard heparin or low-molecular weight heparin). The need for prompt diagnosis and intervention to optimize neurologic outcome is also consistently reported. In response to these patient safety issues, the American Society of Regional Anesthesia and Pain Medicine (ASRA) convened its Third Consensus Conference on Regional Anesthesia and Anticoagulation. Practice guidelines or recommendations summarize evidence-based reviews. However, the rarity of spinal hematoma defies a prospective randomized study, and there is no current laboratory model. As a result,the ASRA consensus statements represent the collective experience of recognized experts in the field of neuraxial anesthesia and anticoagulation. These are based on case reports, clinical series, pharmacology,hematology, and risk factors for surgical bleeding. An understanding of the complexity of this issue is essential to patient management.

Preliminary results of the Australasian Regional Anaesthesia Collaboration: a prospective audit of more than 7000 peripheral nerve and plexus blocks for neurologic and other complications.

BACKGROUND AND OBJECTIVES: Peripheral nerve blockade is associated with excellent patient outcomes after surgery; however, neurologic and other complications can be devastating for the patient. This article reports the development and preliminary results of a multicenter audit describing the quality and safety of peripheral nerve blockade. METHODS: From January 2006 to May 2008, patients who received peripheral nerve blockade had data relating to efficacy and complications entered into databases. All patients who received nerve blocks performed by all anesthetists during each hospital's contributing period were included. Patients were followed up by phone to detect potential neurologic complications. The timing of follow-up was either at 7 to 10 days or 6 weeks postoperatively, depending on practice location and time period. Late neurologic deficits were defined as a new onset of sensory and/or motor deficit consistent with a nerve/plexus distribution without other identifiable cause, and one of the following: electrophysiologic evidence of nerve damage, new neurologic signs, new onset of neuropathic pain in a nerve distribution area, paresthesia in relevant nerve/plexus distribution area. RESULTS: A total of 6950 patients received 8189 peripheral nerve or plexus blocks. Of the 6950 patients, 6069 patients were successfully followed up. In these 6069 patients, there were a total of 7156 blocks forming the denominator for late neurologic complications. Thirty patients (0.5%) had clinical features requiring referral for neurologic assessment. Three of the 30 patients had a block-related nerve injury, giving an incidence of 0.4 per 1000 blocks (95% confidence interval, 0.08-1.1:1000). The incidence of systemic local anesthetic toxicity was 0.98 per 1000 blocks (95% confidence interval, 0.42-1.9:1000). CONCLUSIONS: These results indicate that the incidence of serious complications after peripheral nerve blockade is uncommon and that the origin of neurologic symptoms/signs in the postoperative period is most likely to be unrelated to nerve blockade.

Morphometric analysis of the skull of the Sahel goat breed: basic and clinical anatomy.

The work reports morphometric analysis of the skulls of the Sahel breed of goat. The calculated metric data (mean +/- SD) included the condylobasal length, 16.94 +/- 1.39 cm, while the orbital circumference was 11.30 +/- 0.48 cm. The foramen magnum height and width were 1.82 +/- 0.11 cm and 1.85 +/- 0.15 cm respectively while the foramen magnum index was 89.81 +/- 8.71. Animals above one year of age had significantly higher values for orbital length including horizontal and vertical diameters, overall skull length, basal length, and neurocranium height than animals aged one year and below. The cornual process length, maximum orbital circumference and horizontal diameter obtained in this study were higher than those reported for other Nigerian goat breeds in the literature. The data for the distances from the facial tuberosity to the infraorbital canal, from the mental foramen to the lateral extent of the alveolar root of the lower incisor, as well as from the mandibular foramen to the base of the mandible and that from the mental foramen to the caudal border of the mandible, which are important clinically in the estimation of craniofacial measurements that will aid regional anaesthesia, were however similar to those reported earlier for the Red Sokoto and West African Dwarf breeds implying that a uniform craniometric estimation for associated regional nerve blocks can be attempted for these goat breeds.

Corticosteroid induced psychosis in the pain management setting.

BACKGROUND: Synthetic corticosteroids are commonly utilized in interventional pain management procedures. These substances have potential side-effects including psychological adverse events. OBJECTIVE: We describe a case of substance-induced psychotic disorder resulting from corticosteroids administration. DESIGN: Case Report. METHODS: We describe a 67-year-old male that, six months prior to being consulted at our center, received a cervical epidural, 4 level medial branch blocks, 4 trigger point injections and a tendon injection in the shoulder all including corticosteroids all in one treatment session. RESULTS: Approximately 7 days following the multiple injections, the patient developed psychotic episodes including racing thoughts, anger, agitation, pressured hyperverbal speech and paranoia. The symptoms spontaneously resolved in approximately 7-10 days. DISCUSSION: Although well known as a potential complication, corticosteroid induced psychosis secondary to interventional pain procedures have never been reported. We further discuss this potential side effect of utilizing corticosteroids and emphasize the need for guidelines regarding steroid utilization.

The advantages and disadvantages of Bier's blocks and haematoma blocks for Colles' fractures in A&E.

In the author's current area of practice the use of either the Bier's block or haematoma block for manipulating distal radial fractures seems to have been based mostly on the A&E consultant's preference. The purpose of this literature review was to determine if there was sufficient evidence on the advantages and disadvantages of each method of regional anaesthesia to advocate the general use of one and the exclusion of the other. When reviewing the literature the author specifically looked in to three key areas to answer this question: 1) the patient's perception of pain experienced during and after the manipulation; 2) patient safety i.e. the documented risks of the anaesthetic type used; and 3) the success of the manipulation as determined by repeat radiographs immediately after the application of a plaster of Paris cast.

[Local and regional anesthesia of the upper limb in emergency hand surgery]. / L'anesthésie locorégionale du membre supérieur dans le cadre de la chirurgie d'urgence de la main.

The very conditions of the emergency led the authors to define the indications for the various modalities of local and regional anaesthesia: intravenous regional anaesthesia, nerve trunk blocks, plexus blocks, interdigital block and local infiltration. The parallel development of anaesthetic drugs with variable systemic toxicity and a duration of action inversely proportional to the toxicity now allows precise adaptation of the anaesthesia to the type of lesion, the patient's general condition, the practical conditions of the emergency and the surgical technique selected, provided the anaesthetist is fully aware of the traps to be avoided, which can only be based on a long practice of local and regional anaesthesia in elective surgery.