Effects of subconjunctival ropivacaine, liposomal bupivacaine, and mepivacaine on corneal sensitivity in healthy horses.

OBJECTIVE: To evaluate corneal sensitivity and adverse events following subconjunctival administration of three local anesthetics in horses. STUDY DESIGN: Randomized, masked, crossover study. ANIMALS: Twelve healthy adult mares. METHODS: The subconjunctival space of the treated eye was injected with 0.2 mL of liposomal bupivacaine (1.3%), ropivacaine (0.5%), or mepivacaine (2%). All horses received each medication once and the contralateral eye received saline (control). Corneal touch threshold (CTT) was measured using a Cochet-Bonnet esthesiometer before sedation, after sedation, and at specified intervals until it returned to baseline. Ocular examinations were performed at 24-, 72, and 168 h post-injection to monitor for adverse effects. RESULTS: The mean total time of anesthesia (TTA) was 168.3 min for ropivacaine, 169.2 min for liposomal bupivacaine, 103.3 min for mepivacaine and 30.7 min for the control. TTA for liposomal bupivacaine (p < .001) and ropivacaine (p = .001) was longer than the control. TTA for mepivacaine was not different from the control (p = .138), liposomal bupivacaine (p = .075) or ropivacaine (p = .150). Injection site hemorrhage reduced TTA regardless of treatments (p = .047). No adverse effects attributed to injections were noted. CONCLUSION: All three medications were well tolerated. Subconjunctival administration of ropivacaine and liposomal bupivacaine resulted in longer TTAs compared to the control; however, their TTAs were not different from that of mepivacaine. CLINICAL SIGNIFICANCE: Subconjunctivally administered liposomal bupivacaine and ropivacaine are viable options to provide prolonged corneal analgesia in horses. Future studies are needed to assess the efficacy in diseased eyes.

Injectable and topical local anesthetics for acute dental pain: 2 systematic reviews.

BACKGROUND: Local anesthesia is essential for pain control in dentistry. The authors assessed the comparative effect of local anesthetics on acute dental pain after tooth extraction and in patients with symptomatic irreversible pulpitis. TYPES OF STUDIES REVIEWED: The authors searched MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, and the US Clinical Trials registry through November 21, 2020. The authors included randomized controlled trials (RCTs) comparing long- vs short-acting injectable anesthetics to reduce pain after tooth extraction (systematic review 1) and evaluated the effect of topical anesthetics in patients with symptomatic pulpitis (systematic review 2). Pairs of reviewers screened articles, abstracted data, and assessed risk of bias using a modified version of the Cochrane risk of bias 2.0 tool. The authors assessed the certainty of the evidence using the Grading of Recommendations Assessment, Development and Evaluation approach. RESULTS: Fourteen RCTs comparing long- vs short-acting local anesthetics suggest that bupivacaine may decrease the use of rescue analgesia and may not result in additional adverse effects (low certainty evidence). Bupivacaine probably reduces the amount of analgesic consumption compared with lidocaine with epinephrine (mean difference, -1.91 doses; 95% CI, -3.35 to -0.46; moderate certainty) and mepivacaine (mean difference, -1.58 doses; 95% CI, -2.21 to -0.95; moderate certainty). Five RCTs suggest that both benzocaine 10% and 20% may increase the number of people experiencing pain reduction compared with placebo when managing acute irreversible pulpitis (low certainty). PRACTICAL IMPLICATIONS: Bupivacaine may be superior to lidocaine with epinephrine and mepivacaine with regard to time to and amount of analgesic consumption. Benzocaine may be superior to placebo in reducing pain for 20 through 30 minutes after application.

Treatment with CoreTherm in 570 patients with prostate volumes of 80-366 ml: an evaluation of short- and long-term retreatment risk.

INTRODUCTION: CoreTherm (ProstaLund AB, Lund, Sweden) is an outpatient treatment option in men with lower urinary tract symptoms and catheter-dependent men with chronic urinary retention caused by benign prostatic obstruction (BPO). CoreTherm is high-energy transurethral microwave thermotherapy with feedback technique. Modern treatment with CoreTherm includes transurethral intraprostatic injections of mepivacaine and adrenaline via the Schelin Catheter (ProstaLund AB, Lund, Sweden) and is often referred to as the CoreTherm Concept. OBJECTIVES: The aim of this study was to evaluate the short- and long-term retreatment risk in men with large prostates and BPO or chronic urinary retention, all primarily treated with CoreTherm. MATERIAL AND METHODS: All men from the same geographical area with prostate volumes ≥ 80 ml treated 1999-2015 with CoreTherm and having BPO or were catheter-dependent due to chronic urinary retention, were included. End of study period was defined as December 31, 2019. RESULTS: We identified and evaluated 570 men treated with CoreTherm, where 12% (71 patients) were surgically retreated during the follow-up. Mean follow-up was 11 years, and maximum follow-up was 20 years. The long-term retreatment rate in our study was 23%. A majority of these could be retreated with CoreTherm or TURP, with only 3% requiring open surgery. CONCLUSION: We conclude that CoreTherm is a suitable outpatient treatment option in patients with profoundly enlarged prostates, regardless of age, prostate size, and reason for treatment.

Mechanical sensitivity changes in pericranial muscles after local anesthesia and experimentally induced pain in the temporalis tendon: Implications for headache and facial pain.

OBJECTIVES: To assess changes in mechanical sensitivity of the pericranial muscles in healthy individuals after a local anesthetic block of the temporalis tendon. In addition, to assess, if experimentally induced temporalis tendon pain, can lead to an increase in mechanical sensitivity of the pericranial muscles and reports of headache. METHODS: 40 healthy participants were recruited for this randomized, double-blinded, controlled experiment, and were randomly injected with mepivacaine and isotonic saline into the dominant-side temporalis tendon in two different sessions, and either nerve growth factor (n = 20) or isotonic saline (n = 20) in a third session. Mechanical sensitivity was assessed in the temporalis, masseter, and trapezius muscles as well as in the temporalis tendon, on the dominant side, before and 10 minutes after each injection, and in a fourth session two days after the third session. Pain drawings and headache diaries were kept for 30 days after the final session to register any developing pain or headache. RESULTS: Mepivacaine injection into the temporalis tendon caused a significant decrease in mechanical sensitivity in the temporal tendon (-54.5%) and the masseter (-15.4%) muscle (P < 0.05) but not the temporalis (-12.1%) and trapezius muscles (-12.7%) (P > 0.05). Nerve growth factor injection into the temporalis tendon caused a significant increase in mechanical sensitivity in the tendon (+15.4%) and masseter muscle (+14.4%) (P < 0.05) but not the temporalis (+2.8%) or trapezius muscles (+3.1%) (P > 0.05). A significant increase was found for headache frequency in the first seven days (P < 0.05) after nerve growth factor injection compared to after isotonic saline injection, but not intensity (P > 0.05). CONCLUSION: These findings suggest that the therapeutic effect of temporalis tendon anesthetic injections on facial pain and headaches are most likely not only due to a direct effect of the local anesthetic on the temporalis tendon but rather to a more generalized block of the nerves in the area. In addition, the temporal tendon may contribute to the pathophysiological processes of headache.

Complications following equine sacroiliac region analgesia are uncommon: A study in 118 horses.

BACKGROUND: Diagnosis of sacroiliac region pain is supported by a positive response to sacroiliac region analgesia (SIRA). Varying techniques have been described for SIRA; with clinician preference often dictating method. Potential complications following SIRA include ataxia and recumbency. No study has specifically evaluated the prevalence of complications. OBJECTIVES: To describe the complication prevalence following SIRA in a referral clinic. STUDY DESIGN: Retrospective cohort study. METHODS: Review of records from horses presented to two of the authors at Rossdales, Newmarket, between January 2014 and December 2018, that underwent SIRA. Injection was performed using a blind midline approach with 20 mL mepivacaine (Intra-Epicaine 20mg/ml; Dechra) infiltrated through a straight 18 gauge 8.9cm spinal needle subdivided into four sub-locations per block. RESULTS: 118 horses were included, with 167 individual blocks. One horse showed a mild hindlimb gait abnormality following SIRA, which resolved uneventfully over 3 hours; complication rate 1/118 horses (0.85%; 95% CI: 0,2.5%), 1/167 joints (0.60%; 95% CI: 0,1.8%). SIRA subjectively improved lameness/performance in 132/167 (79%) joints. 49/118 (42%) received bilateral SIRA with 53/118 (45%) evaluated ridden following SIRA. MAIN LIMITATIONS: Small population numbers with low complication prevalence rate. CONCLUSIONS: SIRA, using the described technique, has a low (0.85%) prevalence of complications.

Capsaicin-Cyclodextrin Complex Enhances Mepivacaine Targeting and Improves Local Anesthesia in Inflamed Tissues.

Acidic environments, such as in inflamed tissues, favor the charged form of local anesthetics (LA). Hence, these drugs show less cell permeation and diminished potency. Since the analgesic capsaicin (CAP) triggers opening of the TRPV1 receptor pore, its combination with LAs could result in better uptake and improved anesthesia. We tested the above hypothesis and report here for the first time the analgesia effect of a two-drug combination (LA and CAP) on an inflamed tissue. First, CAP solubility increased up to 20 times with hydroxypropyl-beta-cyclodextrin (HP-ß-CD), as shown by the phase solubility study. The resulting complex (HP-ß-CD-CAP) showed 1:1 stoichiometry and high association constant, according to phase-solubility diagrams and isothermal titration calorimetry data. The inclusion complex formation was also confirmed and characterized by differential scanning calorimetry (DSC), X-ray diffraction, and 1H-NMR. The freeze-dried complex showed physicochemical stability for at least 12 months. To test in vivo performance, we used a pain model based on mouse paw edema. Results showed that 2% mepivacaine injection failed to anesthetize mice inflamed paw, but its combination with complexed CAP resulted in pain control up to 45 min. These promising results encourages deeper research of CAP as an adjuvant for anesthesia in inflamed tissues and cyclodextrin as a solubilizing agent for targeting molecules in drug delivery.

Optimal local anesthetic regimen for saddle block in ambulatory anorectal surgery: an evidence-based systematic review.

BACKGROUND: Ambulatory anorectal surgery requires an anesthetic of short duration but profound depth. Saddle block anesthesia (SBA) can provide dense sacral anesthesia with minimal motor blockade, but the ideal local anesthetic agent remains undefined. This systematic review aims to identify the optimal SBA regimen for ambulatory anorectal surgery. METHODS: We sought randomized trials examining SBA for ambulatory anorectal surgery and stratified patients into four subgroups according to local anesthetic type and dose: (1) longer acting, higher dose; (2) longer acting, lower dose; (3) shorter acting, higher dose; and (4) shorter acting, lower dose. Longer acting agents included bupivacaine and levobupivacaine; shorter acting agents included chloroprocaine, mepivacaine, and prilocaine. Lower dose was defined as ≤5 mg and ≤20 mg for longer and shorter acting local anesthetics, respectively. The primary outcome was time to discharge; secondary outcomes included times to sensory and motor block regression, urine voiding, and ambulation, as well as block success. RESULTS: A total of 11 trials (1063 patients) were included. Overall study quality and reporting consistency was poor. Doses ranged from 1.5-7.5 mg to 3-30 mg of longer and shorter acting local anesthetics, respectively. Hyperbaric local anesthetics were used in eight trials (953 patients, 86%). The median time to discharge appeared similar across all subgroups with an overall time of 182 (IQR 102) min. The use of long-acting, lower dose regimens was associated with a faster median time to motor block regression. Block success approached 99% among all trials. CONCLUSIONS: There is presently insufficient qualitative and quantitative evidence to identify an optimal SBA regimen for ambulatory anorectal surgery. Nonetheless, we found that doses as low as 1.5 and 3 mg of longer and shorter acting hyperbaric local anesthetics, respectively, can achieve effective and reliable SBA with timely hospital discharge. Despite similar discharge times, longer acting, lower dose local anesthetics may produce faster motor block regression following SBA for ambulatory anorectal surgery.

Safety of CT-guided cervical nerve root infiltrations using a dorsal approach.

Cervical nerve root infiltrations are frequently performed in patients with radiculopathy, and computed tomography (CT) is commonly used for image guidance. With the traditional anterolateral approach, catastrophic side events due to spinal ischemia have been reported. To minimize risk, a dorsal approach has been advised, but the safety of this dorsal approach has not been studied systematically. In a 5-year period, 137 cervical nerve root infiltrations using a dorsal approach were performed on 109 patients and retrospectively reviewed. In our series, no major complications like spinal ischemia, spondylodiscitis, large hematomas with the need for surgery or severe allergic reactions occurred. In conclusion, using a dorsal approach, CT-guided cervical nerve root infiltrations with an extraforaminal needle position seem to be a safe intervention.

Effect of vasopressin as a local anesthetic in mice.

We sought to elucidate how the local administration of mepivacaine hydrochloride and vasopressin via the tail affects the peripheral blood flow volume, tissue dynamics, and mepivacaine's anesthetic effect in mice. Two-hundred and twenty-six male ICR mice were used in this study. Blood flow was measured after administering mepivacaine alone or mepivacaine with either 0.03, 0.3, or 3.0 U/mL vasopressin or 10 µg/mL epinephrine via the tail tissue. The tail tissue and blood dynamics were measured using 3H-labeled mepivacaine hydrochloride with vasopressin or epinephrine. The compound nerve action potential (CNAP) was measured to clarify the anesthetic effect after administering mepivacaine with 0.3 U/mL vasopressin. The statistical methods employed were Steel-Dwass test, Mann-Whitney U test, Dunnett's test, and Tukey test. P < 0.05 indicated statistical significance. The results revealed that the local administration of ≥ 0.03 U/mL vasopressin reduced local blood flow and prolonged 3H-M localization in the tail tissue in a concentration-dependent manner. Addition of 0.3 U/mL vasopressin enhanced and prolonged the anesthetic effect of mepivacaine. The findings suggest that adding vasopressin to a local anesthetic regimen may be effective, and thus it could be applied as a vasoconstrictor.

Selective local anesthesia versus corticosteroid infiltration on low back pain: a randomized clinical trial. / Anestesia local selectiva frente a infiltración de corticosteroides en el dolor lumbar: ensayo clínico aleatorizado.

ANTECEDENTS AND OBJECTIVE: Local infiltrations are second line therapy in the treatment of chronic low back pain, although their use is controversial in the literature. Our objective was to compare the effectiveness of 2 types of infiltration at the paravertebral lumbar level in two groups of patients diagnosed with low back pain: corticosteroids, and selective local anaesthetic administered using segmental neural therapy (SNT). MATERIAL AND METHODS: Double-blind clinical trial in 55 patients diagnosed with low back pain in the neurosurgery department of the Hospital Central de la Defensa Gómez Ulla. Patients were randomised to 2 treatment groups to receive either paravertebral injections of corticosteroids or SNT. Outcomes were measured using a visual analogue scale, the Oswestry Disability Index, the Short Form-36, and patient satisfaction at the start of treatment (baseline) and at 3 and 12 months post intervention. RESULTS: The combined treatment group showed a statistically significant improvement in Oswestry Disability Index at 3 months. The SNT group showed a statistically significant improvement in baseline visual analogue scale vs. visual analogue scale at 3 (1.398cm, p=0.001) and 12 months (0.791cm, p=0.007). No differences were observed in the remaining variables measured. The percentage of patients that would repeat the treatment was 81% and 83%, respectively. CONCLUSIONS: Significant pain relief was achieved with SNT, and disability improved with the combined treatment. Although clinical improvement was limited, patients were satisfied. Local infiltrations should be considered as an alternative treatment for chronic low back pain. CLINICAL TRIAL REGISTRATION: This clinical trial was registered at the European Union Clinical Trials Register with EUDRA-CT number 2015-001146-29.

Prospective randomized investigation of topical anesthesia during unilateral laparoscopic ovariectomy in horses.

OBJECTIVE: To compare pain-related responses in mares receiving topical or injected anesthesia of the ovarian pedicle prior to standing unilateral laparoscopic ovariectomy. STUDY DESIGN: Prospective randomized, blinded, placebo-controlled study. ANIMALS: Fifteen healthy research mares. METHODS: Mares were restrained in stocks and administered sedation. A right or left paralumbar ovariectomy was performed by using a laparoscopic portal and two instrument portals. Mares were divided into two treatment groups, and equal volumes of mepivacaine anesthesia were administered either topically (n = 8) or by injection into the ovarian pedicle (n = 7). Saline controls were simultaneously administered topically (n = 7) or by injection (n = 8), and surgeons were blinded to the treatment group. Ovarian removal was performed with traumatic forceps and a blunt tip vessel sealer and divider. Pain responses were measured by operative visual analog scale (VAS) scoring and perioperative serum cortisol response. Visual analog scale and serum cortisol were compared between groups by using Mann-Whitney testing. Serum cortisol concentrations were evaluated using repeated-measures one-way analysis of variance. RESULTS: Ovaries were removed in all mares by using the described technique without operative complications. Quantity of sedation required to complete the procedure, operative VAS scores, and perioperative cortisol concentrations did not differ between treatment groups. CONCLUSION: Application of topical mepivacaine to the ovary provided intraoperative analgesia similar to injection of the ovarian pedicle when performing unilateral standing laparoscopic ovariectomy in mares. CLINICAL SIGNIFICANCE: Topical anesthesia application to the ovary could provide an alternative to laparoscopic needle use, reducing the risk of inadvertent trauma to the pedicle or other visceral organs during laparoscopic ovariectomy.

[Objective assessment of mental nerve local anesthesia]. / Ob''ektivnaia otsenka urovnia mestnogo obezbolivaniia podborodochnogo nerva.

AIM: To study the reaction of the mental nerve to selective stimulation of thin nerve fibers by thermal stimuli during conduction anesthesia. MATERIAL AND METHOD: The pilot study involved 24 healthy volunteers: 13 subjects were injected with a 4% solution of articaine-containing anesthetic with a vasoconstrictor in a ratio of 1:200 000 (pH 4.8-5.4) and 11 subjects - a 3% solution of mepivacaine-containing local anesthetic without a vasoconstrictor (pH value 5.8-6.4). The registration of evoked potentials was performed twice: before local anesthesia and 5 minutes after anesthesia. With the help of disposable carpal dental injectors, local anesthesia was performed near the mental foramen in order to anesthetize the innervation region of the mental nerve through a conductive type. The evoked potentials (VP) were recorded on a Nicolet instrument (USA) with Bravo evoked potentials software. The study of thermal EPs was performed using a Contact heat evoked potential stimulator (CHEPS) device ('Medoc Ltd, Ramat Yishai', Israel). The base and peak temperature were set at 33 and 54 °C, correspondingly. RESULTS: The evoked potentials for thermal stimulation demonstrated a significant decrease in the amplitude of all components and the elongation of the LP of the main negative-positive N2-P2 complex after anesthesia compared with the initial thermal EP. The complete disappearance of thermal responses was observed in 14 (58%) of 24 study participants, minor changes were seen in 3 (12.5%) cases only. The total response disappearance was observed in 10 (77%) of 13 participants after articaine and in 3 (27%) of 11 - after mepivacaine (p<0.05), weak changes were registered in 2 (15%) cases in the articaine group and in 1 (9%) case in the mepivacaine group. CONCLUSION: A 4% solution of articaine is somewhat more effective for pain relief of teeth and bone since it often causes deeper anesthesia, and a 3% solution of mepivacaine without a vasoconstrictor is physiologically more suitable for working with soft tissues.

Ipsilateral transient amaurosis, mydriasis and light reflex absence after subconjunctival local anesthesia with mepivacaine in three patients with refractory glaucoma - a case report.

BACKGROUND: The subconjunctival anesthesia with local anesthetics is considered as a low-risk procedure allowing ocular surgery without serious complications typical for retro- or parabulbar anesthesia, especially in patients with preexisting Optic Nerve damage. We report development of ipsilateral transient amaurosis accompanied with mydriasis and both, direct and consensual light response absence. CASE PRESENTATION: Three patients with advanced refractory glaucoma undergoing laser cyclophotocoagulation (CPC) for intraocular pressure lowering experienced these adverse effects just few minutes after subconjunctival injection of mepivacaine 2% solution (Scandicaine® 2%, without vasoconstrictor supplementation). The vision was completely recovered to usual values in up to 20 h after mepivacaine application. Extensive ophthalmological examination, including cranial magnetic resonance imaging (MRI), revealed no further ocular abnormalities, especially no vascular constriction or thrombotic signs as well as no retinal detachment. The oculomotor function remained intact. The blockade of ipsilateral ciliary ganglion parasympathetic fibers by mepivacaine may be the responsible mechanism. Systemic pathways as drug-drug interactions seem to be unlikely involved. Importantly, all three patients tolerated the same procedure previously or at a later date without any complication. Overall, our thoroughly elaborated risk management could not determine the causative factor explaining the observed ocular complications just in the current occasion and not at other time points. CONCLUSIONS: Doctors should be aware and patients should be informed about such rare complications after subconjunctival local anesthetics administration. Adequate risk management should insure patients' safety.

Using chloroprocaine for spinal anaesthesia in outpatient knee-arthroscopy results in earlier discharge and improved operating room efficiency compared to mepivacaine and prilocaine.

PURPOSE: Knee arthroscopies are regularly carried out in an outpatient setting. The purpose of this retrospective analysis was to investigate the impact of different local anaesthetics for spinal anaesthesia on operating room efficiency (perioperative process times) and postoperative recovery. This study aims to determine the optimal LA for SPA in patients undergoing knee arthroscopy at a day-surgery centre. METHODS: Anaesthesia records of all patients undergoing knee arthroscopy under spinal anaesthesia from 2010 until 2017 were analysed. Patients were categorised as having received spinal anaesthesia with prilocaine, mepivacaine or chloroprocaine. RESULTS: Three-hundred and nine patients were included. Postoperative recovery was significantly faster for chloroprocaine 1% compared with both other local anaesthetics regarding all stages of recovery until discharge. Perioperative processes and surgery time were significantly shorter when chloroprocaine was used. Early postoperative pain occurred more frequently and earlier after spinal anaesthesia with chloroprocaine. Nevertheless, pain intensity did not differ between groups. CONCLUSION: Spinal anaesthesia provides reliable blocks for outpatient knee arthroscopy. Considerations on the choice of local anaesthetic for spinal anaesthesia must include not only the recovery profile, but also the impact on operating room efficiency. Due to a superior recovery profile, low incidences of adverse side effects and raised operating room efficiency, chloroprocaine is the recommendable local anaesthetic for spinal anaesthesia in patients undergoing knee arthroscopy in an ambulatory setting. Since the frequency of SPA in patients undergoing outpatient knee arthroscopy is rising yearly, the results of this study are of high clinical relevance. The use of chloroprocaine leads to improved recovery, optimized perioperative processes and consecutively to a raised OR efficiency. LEVEL OF EVIDENCE: III.

Resistance to local anesthesia in people with the Ehlers-Danlos Syndromes presenting for dental surgery

BACKGROUND: People with the Ehlers-Danlos Syndromes (EDS), a group of heritable disorders of connective tissue, often report experiencing dental procedure pain despite local anesthetic (LA) use. Clinicians have been uncertain how to interpret this apparent LA resistance, as comparison of EDS and non-EDS patient experience is limited to anecdotal evidence and small case series. The primary goal of this hypothesis-generating study was to investigate the recalled adequacy of pain prevention with LA administered during dental procedures in a large cohort of people with and without EDS. A secondary exploratory aim asked people with EDS to recall comparative LA experiences. METHODS: We administered an online survey through various social media platforms to people with EDS and their friends without EDS, asking about past dental procedures, LA exposures, and the adequacy of procedure pain prevention. Among EDS respondents who both received LA and recalled the specific LA used, we compared agent-specific pain prevention for lidocaine, procaine, bupivacaine, mepivacaine, and articaine. RESULTS: Among the 980 EDS respondents who had undergone a dental procedure LA, 88% (n = 860) recalled inadequate pain prevention. Among 249 non EDS respondents only 33% (n = 83) recalled inadequate pain prevention (P < 0.001 compared to EDS respondents). The agent with the highest EDS-respondent reported success rate was articaine (30%), followed by bupivacaine (25%), and mepivacaine (22%). CONCLUSIONS: EDS survey respondents reported nearly three times the rate of LA non-response compared to non-EDS respondents, suggesting that LAs were less effective in preventing their pain associated with routine office dental procedures.

New local anesthetics.

Local anesthetics are used for performing various regional anesthesia techniques to provide intraoperative anesthesia and analgesia, as well as for the treatment of acute and chronic pain. Older medications such as lidocaine and bupivacaine as well as newer ones such as mepivacaine and ropivacaine are being used successfully for decades. Routes of administration include neuraxial, perineural, intravenous, various infiltrative approaches, topical, and transdermal. There are new innovations with the use of older local anesthetics in a novel manner, in addition to the development and use of new formulations. This chapter seeks to summarize the pharmacokinetics of local anesthetics and address the role of newer local anesthetics, as well as clinical implications, safety profiles, and the future of local anesthetic research. Finally, some clinical pearls are highlighted.

Dental anaesthesia for children - effects of a computer-controlled delivery system on pain and heart rate: a randomised clinical trial.

Local anaesthesia in dentistry is usually given by conventional injection through a syringe. In this randomised, single-blind, split-mouth clinical study we evaluated the perception of pain and changes in heart rate in children being given dental local anaesthesia using a computer-controlled device compared with that given using a traditional syringe. Participants were in good general health with no contraindications to local anaesthetics. One half of each maxilla was anaesthetised using each technique, the order having been randomly selected according to a computer-generated sequence. The hypothesis was that the controlled anaesthetic flow rate results in virtually imperceptible injections. The outcomes were the perception of pain and the heart rate. Seventy-six children aged from 5-12 years old participated in this study. The mean (SD) pain score of the conventional injection was 5.51 (2.46) and the mean (SD) heart rate was 2.72 (6.76), which were significantly higher than those of the computerised delivery system, which were 4.74 (2.8) and 0.34 (7.3) (p=0.04). More patients anaesthetised with the traditional syringe technique required a second injection (n=21). These results suggest that dental anaesthesia given to children with a computer-controlled delivery system reduced pain better than that given with a conventional syringe.

Peribulbar anesthesia in sclero-retinal surgery: two quadrants vs single injection.

PURPOSE: To evaluate the advantage of peribulbar anesthesia in two quadrants (infero-temporal and upper nasal) vs single injection technique (infero-temporal) for scleral rhegmatogenous retinal detachment surgery (RRD). PATIENTS AND METHODS: 57 patients, aged between 33 and 75 years (57.01 ± 8.68), waiting for retinal detachment surgery, were randomized in two groups: a group S (29 patients), with single quadrant injection technique and a group C (28 patients) with two quadrants injection. Patients in Group S were injected in two quadrants with a 10 ml mixture containing Mepivacaine 2% 5 ml and Ropivacaine 0.75% 5 ml, with hyaluronidase 10 IU/ ml. Patients in group C were injected with the same anesthetic mixture in one quadrant. Number of additional injection, during surgery, in two groups, were reported. Pain was tested with VAS (Verbal Analogue Scale 0-10) after regional block, when muscles were insulated, during scleral buckling positioning, when conjunctive was closed and 6, 12, 24 hours after surgery. RESULTS: The need for a second peribulbar injection of anesthetic occurred in 9 patients of group C (32.14%); further injection was necessary in 1 patient (3.57%) of group S during scleral buckling (VAS = 7), statistically significant (p <0.05). Postoperative VAS 6 - 12 - 24 hours after surgery was not significant. CONCLUSIONS: The peribulbar anesthesia may be proposed in scleral surgery of retinal detachment; the injection in two quadrants secured solid and satisfactory anesthesia, increasing the outcome of retinal surgery in loco-regional anesthesia.

Evaluation of the plasmatic level of mepivacaine in different anatomical regions

BACKGROUND: To evaluate the serum level of the local anesthetic mepivacaine 3% without vasoconstrictor in patients who underwent procedures performed in the anterior and posterior maxilla, through a method of possible extraction to quantify it in human plasma by high performance liquid chromatography (HPLC). MATERIAL AND METHODS: This was a hybrid study consisting of 18 patients (7 females and 11 males) classified as ASA I, adults and with normal body mass index, submitted to procedures in the anterior region (group I) and posterior region of the maxilla (group II). For 40 minutes, five 6 ml blood samples were collected every 10 minutes after infiltrative injection in each region of the maxilla. Serum levels of the drug were obtained through HPLC. Blood pressure (BP) and heart rate (HR) were measured throughout the procedure. RESULTS: When compared to the general average of the concentrations of each group, significant values (p < 0.05) with greater absorption were observed for the anterior region of the maxilla (group I). There was no significant difference when comparing blood pressure (BP) and heart rate (HR) values. CONCLUSIONS: The concentrations found are safe for infiltrative anesthesia in the analyzed patients, there was a higher plasma level of the local anesthetic in the anterior region of the maxilla and there was no change in HR and BP in relation to the anesthetized area

Single tooth anaesthesia: a new approach to the paediatric patient. A clinical experimental study.

AIM: The objective of this study is to assess the efficacy of the STA Wand System with respect to pain and fear reduction in paediatric patients and by using the Single Tooth Anaesthesia (STA) technique. MATERIALS AND METHODS: Patients included children and teenagers between 6 and 17 years of age, who required the administration of local anaesthesia prior to expected treatments. Local anaesthesia was performed by means of the electronic STA Wand System (Milestone scientific., Inc.) adopting the Single Tooth Anaesthesia (STA) technique. Pre- and post-anaesthesia, the patients were asked to complete the Wong-Baker faces image scale and the provider filled in the Frankl Scale. RESULTS: All treatments were completed successfully and no collaboration issues were recorded. Frankl's assessment showed that 91% of patients regarded dental experience positively. The efficacy of the computer-assisted anaesthesia was at 100% when treating primary teeth, and 70% for procedures on permanent teeth. Almost the totality of treated patients (94%) gave a positive evaluation after having tried the device with STA technique. Only 6% of the patients assessed the procedure negatively. CONCLUSIONS: The STA technique allows for absence of anticipatory anxiety, absence of physical pain, no anaesthetic effects in the perioral tissues and a controllable, lower dosage of the anaesthetic liquid.