Patient Comfort, Safety, and Effectiveness of Resilient Hyaluronic Acid Fillers Formulated With Different Local Anesthetics.

BACKGROUND: Maximizing patient comfort during hyaluronic acid gel injection is a common concern that is usually addressed by selecting fillers with lidocaine. OBJECTIVE: Two randomized, double-blinded, split-face trials aimed to demonstrate noninferiority of specific hyaluronic acid fillers incorporating mepivacaine (RHA-M) versus their lidocaine controls, at providing pain relief. METHODS: Thirty subjects per trial received injections of RHA R -M versus RHA R , and RHA4-M versus RHA4, respectively, in the perioral rhytids (PR) and nasolabial folds (NLF). Pain was assessed on a visual analog scale; aesthetic effectiveness was evaluated with validated scales, and safety was monitored based on common treatment responses (CTRs) and adverse events (AEs). RESULTS: RHA-M fillers proved as effective as their lidocaine counterparts at reducing pain (noninferior, p < .0002 and p < .0001). Bilateral wrinkle improvement was measured both in the PR (-1.5 ± 0.6 points on each side) and in the NLF (-1.8 ± 0.6 and -1.9 ± 0.5 points) trials at one month, with virtually identical responder rates (≥96.7%). Common treatment responses and AEs were similar between treated sides, and none was clinically significant. CONCLUSION: Resilient hyaluronic acid fillers with either mepivacaine or lidocaine are equally effective at reducing pain during treatment and equally performant and safe for correction of dynamic facial wrinkles and folds.

Influence of clinical and experimental intra-articular inflammation on neutrophil gelatinase-associated lipocalin concentrations in horses.

OBJECTIVE: To investigate neutrophil gelatinase-associated lipocalin (NGAL) concentrations in serum and synovial fluid (SF) from horses with joint inflammation. STUDY DESIGN: Experimental studies and retrospective clinical study. SAMPLE POPULATION: Serum and SF samples were available from healthy horses (n = 19), clinical cases, and horses with experimental joint inflammation. Clinical cases included horses with (n = 10) or without (n = 10) septic arthritis. Experimental intra-articular inflammation was induced by lipopolysaccharide (LPS; n = 7, severe inflammation), lidocaine (n = 6, moderate inflammation), or mepivacaine (n = 6, mild inflammation). METHODS: Availability of samples was based on approval from the local ethical committee and from the Danish Animal Experiments Inspectorate. Neutrophil gelatinase-associated lipocalin was measured with a previously validated enzyme-linked immunosorbent assay. Repeated-measurements one- and two-way analysis of variance and correlation analysis were used to analyze NGAL concentrations and white blood cell counts (WBC). RESULTS: After injection of LPS or lidocaine, SF NGAL concentrations increased 343- (P = .0035) and 60-fold (P = .0038) relative to baseline, respectively. Serum NGAL also increased in both groups (P < .05) but to lower concentrations than in SF. Concentrations were higher after injection of lidocaine SF NGAL than after injection of mepivacaine (P < .05) at 6 and 12 hours. Synovial fluid concentrations of NGAL were higher in horses with septic arthritis than in the nonseptic group (P = .0070) and in healthy controls (P = .0071). Concentrations of NGAL correlated with WBC in SF (P < .0001, R2 = 0.49) and in blood (P = .0051, R2 = 0.27). CONCLUSION: Neutrophil gelatinase-associated lipocalin concentrations increased in SF in response to experimentally induced and naturally occurring joint inflammation. Synovial fluid NGAL concentration correlated with WBC and, thus, seems to reflect intensity of joint inflammation. CLINICAL SIGNIFICANCE: Neutrophil gelatinase-associated lipocalin may prove to be a useful biomarker of joint inflammation and infection in horses.

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.

Nonformalin Fixative Agents: A Comparative Study of Fixative Efficacy and Histomorphology.

OBJECTIVES: Formalin is a gold standard fixative agent. However, formalin possesses health hazards and is not always available in rural areas. The objective of this study was to compare tissue fixative efficacy of nonformalin fixative agents with formalin. METHODS: Oral tissues obtained during impacted tooth removal were collected. The tissue fragments were sectioned and fixed in 4 different fixatives; 30% jaggery, 70% ethanol, 2% mepivacaine with 1:100 000 epinephrine, or formalin for 24 and 72 hours. All specimens were then immersed in formalin for another 24 hours and processed according to standard protocol. Hematoxylin and eosin-stained sections were evaluated by a pathologist. The cellular structure, cellular outline, and quality of staining were graded from 1 to 3 and average fixative efficacy scores were compared using 1-way analysis of variance. Fixative artifacts were described. RESULTS: Fixative efficacy scores of 70% ethanol and 30% jaggery at 24 and 72 hours were not statistically different from those of formalin. Conversely, 2% mepivacaine demonstrated significantly lower fixative efficacy scores than other agents. Although efficacy of each fixative was not statistically different between 24 and 72 hours, efficacy of 70% ethanol was markedly reduced at 72 hours when compared with others. Acantholysis of epithelial cells was the most notable artifact at 72 hours when fixed with nonformalin fixative agents. CONCLUSION: Both 70% ethanol and 30% jaggery provided acceptable fixative efficacy at 24 hours. However, only 30% jaggery maintained fixative efficacy at 72 hours. Nevertheless, negative effects on the epithelial cells were unavoidable and should be interpreted with caution.

Efficiency and predictive parameters of outcome of a multimodal pain management concept with spinal injections in patients with low back pain: a retrospective study of 445 patients.

Low back pain is one of the most common diseases of modern civilization. Multimodal pain management (MPM) represents a central approach to avoiding surgery. Short-term results are published rarely and often incomparable because of different treatment concepts. This study compared the subjective and objective parameters as well as the anamnestic and clinical parameters of 445 patients with low back pain before and after inpatient MPM to investigate the influence of this type of therapy on short-term outcome. The majority of patients were very satisfied (39%) or satisfied (58%) with the treatment outcome. The median pain reduction for back pain was 3.0 (IQR 2.88) (numeric rating scale, NRS), thus 66% and 2.75 (IQR 3.38, 62%) for leg pain. The main pain reduction occurred within the first 10 days of treatment and was clinically significant from day 5 onwards. The outcome for patients with hospitalization of more than 10 days was significantly worse. The parameters female sex, BMI of > 30, local pain, and pain duration of 3-24 months had a significantly better outcome. In contrast, age, treatment cause, depression, anxiety, and other diseases had no statistically significant influence on outcome. MPM therapy for more than 5 days seems to be an efficient short-term approach to treating low back pain. Knowledge of some of the outcome predictors helps to early identify patients who require more intensive individual care. In the case of no clear indication for surgery, MPM can be an appropriate treatment option.

Mepivacaine Spinal Anesthesia Facilitates Rapid Recovery in Total Knee Arthroplasty Compared to Bupivacaine.

BACKGROUND: Mepivacaine as a spinal anesthetic for rapid recovery in total knee arthroplasty (TKA) has not been assessed. The purpose of this study is to compare spinal mepivacaine vs bupivacaine for postoperative measures in patients undergoing primary TKA. METHODS: Retrospective review of a prospectively collected single-institution database was performed on 156 consecutive patients who underwent primary TKA. Fifty-three patients were administered mepivacaine and 103 patients were administered bupivacaine. Primary outcomes were urinary retention, length of stay, pain control, opioid consumption, and distance associated with physical therapy. Statistical analysis with univariate logistic regression was performed to evaluate the effect of anesthetic with primary outcomes. RESULTS: Patients undergoing TKA with mepivacaine had a shorter length of stay (28.1 ± 11.2 vs 33.6 ± 14.4 hours, P = .002) and fewer episodes of straight catheterization (3.8% vs 16.5%, P = .021) compared to bupivacaine. Patients administered mepivacaine exhibited slightly higher VAS pain scores and morphine consumption in the postanesthesia care unit (1.3 ± 1.9 vs 0.5 ± 1.3, P = .002; 2.2 ± 3.3 vs 0.8 ± 2.1 equivalents/h, P = .002), but otherwise exhibited no difference in VAS scores or morphine consumption afterwards. There was no need to convert to general anesthesia or transient neurologic symptom complication in either group. CONCLUSION: Mepivacaine for spinal anesthesia with TKA had adequate duration to complete the surgery and facilitated a more rapid recovery with less urinary complications and a shorter length of stay. Patients administered mepivacaine did not display worse pain control or transient neurologic symptoms afterwards.

Local Anesthetic-Induced Myotoxicity After Continuous Adductor Canal Block.

OBJECTIVE: Local anesthetic-induced myotoxicity occurs consistently in animal models, yet is reported rarely in humans. Herein, we describe 3 sentinel cases of local anesthetic myotoxicity after continuous adductor canal block (ACB). CASE REPORT: Three patients underwent total knee arthroplasty that was managed with subarachnoid block plus ACB induced with 1.5% lidocaine or 1.5% mepivacaine bolus followed by 0.2% ropivacaine at 8 mL/h. Although initial postoperative recovery was normal, each patient on either postoperative day 1 or 2 developed progressive, profound weakness of the quadriceps muscles. Clinical course, imaging, and neurophysiologic studies were consistent with myositis. The patients experienced partial to full functional recovery over the ensuing weeks to months. CONCLUSIONS: Clinically apparent local anesthetic-induced myotoxicity has been documented rarely in humans undergoing non-ophthalmic surgery. We report 3 sentinel cases associated with continuous ACB.

Prospective, Randomized Double-Blind Study: Does Decreasing Interscalene Nerve Block Volume for Surgical Anesthesia in Ambulatory Shoulder Surgery Offer Same-Day Patient Recovery Advantages?

BACKGROUND AND OBJECTIVES: In this randomized double-blind prospective study in patients undergoing shoulder arthroscopy, we compared the effects of ultrasound-guided interscalene nerve block using 20 mL (intervention group) and 40 mL (control group) of a mepivacaine 1.5% and bupivacaine 0.5% mixture (1:1 volume) on ipsilateral handgrip strength and other postoperative end points. METHODS: One hundred fifty-four patients scheduled for ambulatory shoulder arthroscopy were randomly assigned to receive a single-injection interscalene block under ultrasound guidance with either 40 mL (control) or 20 mL (intervention) and intravenous sedation. The primary outcome was the change in ipsilateral handgrip strength in the postanesthesia care unit (PACU) measured with a dynamometer. Secondary end points were recorded, including negative inspiratory force, incidences of hoarseness and Horner syndrome, time to readiness for discharge from PACU, time to discharge from PACU, patient satisfaction, time to block resolution, and pain scores. RESULTS: Postoperative handgrip strength was greater in the 20-mL group compared with the 40-mL group (difference in means, 2.3 kg [95% confidence interval, 0.6-4.0 kg]; P = 0.009). A smaller proportion of patients in the intervention group experienced hoarseness postoperatively compared with the control group (odds ratio, 0.26 [95% confidence interval, 0.08-0.82]; P = 0.015). Patient satisfaction and duration of analgesia were similar in both groups. CONCLUSIONS: When used for surgical anesthesia for shoulder arthroscopies in the ambulatory setting, a 20-mL volume in an ultrasound-guided interscalene block preserves greater handgrip strength on the ipsilateral side in the PACU compared with 40 mL without significant decrease in block success, duration of analgesia, and patient satisfaction.

Neurologic Outcomes After Low-Volume, Ultrasound-Guided Interscalene Block and Ambulatory Shoulder Surgery.

BACKGROUND AND OBJECTIVES: Postoperative neurologic symptoms after interscalene block and shoulder surgery have been reported to be relatively frequent. Reports of such symptoms after ultrasound-guided block have been variable. We evaluated 300 patients for neurologic symptoms after low-volume, ultrasound-guided interscalene block and arthroscopic shoulder surgery. METHODS: Patients underwent ultrasound-guided interscalene block with 16 to 20 mL of 0.5% bupivacaine or a mix of 0.2% bupivacaine/1.2% mepivacaine solution, followed by propofol/ketamine sedation for ambulatory arthroscopic shoulder surgery. Patients were called at 10 days for evaluation of neurologic symptoms, and those with persistent symptoms were called again at 30 days, at which point neurologic evaluation was initiated. Details of patient demographics and block characteristics were collected to assess any association with persistent neurologic symptoms. RESULTS: Six of 300 patients reported symptoms at 10 days (2%), with one of these patients having persistent symptoms at 30 days (0.3%). This was significantly lower than rates of neurologic symptoms reported in preultrasound investigations with focused neurologic follow-up and similar to other studies performed in the ultrasound era. There was a modest correlation between the number of needle redirections during the block procedure and the presence of postoperative neurologic symptoms. CONCLUSIONS: Ultrasound guidance of interscalene block with 16- to 20-mL volumes of local anesthetic solution results in a lower frequency of postoperative neurologic symptoms at 10 and 30 days as compared with investigations in the preultrasound period.

Plasma mepivacaine concentrations in patients undergoing third molar surgery.

BACKGROUND: Local anaesthetic-related systemic toxicity mainly results from elevated plasma concentrations of these drugs. We hypothesized that intraoral injection of submaximal doses of mepivacaine does not lead to toxic levels of this drug in blood. This study evaluated the plasma levels of mepivacaine in third molars surgeries. METHODS: Twenty-one patients were randomly assigned into two groups: group I (two unilateral third molars; submaximal dose of mepivacaine 108 mg with epinephrine 54 µg) and group II (four third molars; submaximal dose of mepivacaine 216 mg with epinephrine 108 µg). Blood samples were collected before anaesthesia, and 5, 10, 15, 20, 30, 40, 60, 90 and 120 min after anaesthesia. RESULTS: Individual peak plasma concentrations ranged 0.77-8.31 µg/mL (group I) and from 2.36-7.72 µg/mL (group II). An increase in the average dose of mepivacaine from 1.88 ± 0.12 mg/kg (group I) to 3.35 ± 0.17 mg/kg (group II) increased the mean mepivacaine peak plasma levels from 2.33 ± 0.58 to 4.01 ± 0.69 µg/mL, respectively. Four patients obtained plasma levels of mepivacaine above the threshold for toxicity (5 µg/mL). CONCLUSIONS: Toxic levels of mepivacaine are possible, even when a submaximal dose is used. A twofold increase in the dose of mepivacaine caused the mean peak plasma concentration to increase proportionally, indicating that they may be predicted based on the relation of dose per bodyweight.

Ultrasound-Guided Single-Injection Infraclavicular Block Versus Ultrasound-Guided Double-Injection Axillary Block: A Noninferiority Randomized Controlled Trial.

BACKGROUND: Single-injection ultrasound-guided infraclavicular block is a simple, reliable, and effective technique. A simplified double-injection ultrasound-guided axillary block technique with a high success rate recently has been described. It has the advantage of being performed in a superficial and compressible location, with a potentially improved safety profile. However, its effectiveness in comparison with single-injection infraclavicular block has not been established. We hypothesized that the double-injection ultrasound-guided axillary block would show rates of complete sensory block at 30 minutes noninferior to the single-injection ultrasound-guided infraclavicular block. METHODS: After approval by our research ethics committee and written informed consent, adults undergoing distal upper arm surgery were randomized to either group I, ultrasound-guided single-injection infraclavicular block, or group A, ultrasound-guided double-injection axillary block. In group I, 30 mL of 1.5% mepivacaine was injected posterior to the axillary artery. In group A, 25 mL of 1.5% mepivacaine was injected posteromedial to the axillary artery, after which 5 mL was injected around the musculocutaneous nerve. Primary outcome was the rate of complete sensory block at 30 minutes. Secondary outcomes were the onset of sensory and motor blocks, surgical success rates, performance times, and incidence of complications. All outcomes were assessed by a blinded investigator. The noninferiority of the double-injection ultrasound-guided axillary block was considered if the limits of the 90% confidence intervals (CIs) were within a 10% margin of the rate of complete sensory block of the infraclavicular block. RESULTS: At 30 minutes, the rate of complete sensory block was 79% in group A (90% CI, 71%-85%) compared with 91% in group I (90% CI, 85%-95%); the upper limit of CI of group A is thus included in the established noninferiority margin of 10%. The rate of complete sensory block was lower in group A (proportion difference of 12% [95% CI, 2-22]; P = 0.0091), as was surgical success rate (82% [95% CI, 74%-89%] vs 93% [95% CI, 86%-97%]; proportion difference of 11% [95% CI 1-20]; P = 0.0153). Sensory block onset also was slower in group A (log rank test P = 0.0020). Performance times were faster in group I (231 seconds [95% CI, 213-250]) than in group A (358 seconds [95% CI, 332-387]; P < 0.0001). No statistically significant difference was observed for vascular puncture, paresthesia during block performance, or procedure-related pain. No neurologic complication was noted at follow-up. CONCLUSIONS: We failed to demonstrate that the rate of complete sensory block of the double-injection axillary block is noninferior to the single-injection infraclavicular block. However, the rate of complete sensory block at 30 minutes is statistically significantly lower with the axillary block. The ultrasound-guided single-injection infraclavicular block thus seems to be the preferred technique over the axillary for upper arm anesthesia.

Distribution of Injectate and Sensory-Motor Blockade After Adductor Canal Block.

BACKGROUND: The analgesic efficacy reported for the adductor canal block may be related to the spread of local anesthetic outside the adductor canal. METHODS: Fifteen patients undergoing knee surgery received ultrasound-guided injections of local anesthetic at the level of the adductor hiatus. Sensory-motor block and spread of contrast solution were assessed. RESULTS: Sensation was rated as "markedly diminished" or "absent" in the saphenous nerve distribution and "slightly diminished" in the sciatic nerve territory without motor deficits. Contrast solution was found in the popliteal fossa. CONCLUSIONS: The spread of injectate to the popliteal fossa may contribute to the analgesic efficacy of adductor canal block.

Safety of CT-Guided Lumbar Nerve Root Infiltrations. Analysis of a Two-Year Period.

Selective nerve root infiltrations are frequently performed in patients with lumbar radiculopathy. Computed tomography (CT) is now commonly used for image guidance. Despite the widespread use of CT-guided lumbar nerve root infiltrations few studies have systematically examined the safety of this approach. In a two-year period, 231 lumbar nerve root infiltrations were performed on in-patients and were retrospectively reviewed. No major complications like inflammation (especially spondylodiscitis), large haematomas requiring surgery, severe allergic reactions or spinal ischaemia occurred. In accordance with other published studies, CT-guided lumbar nerve root infiltrations seem to be safe. To minimize the risk of catastrophic neurological complications due to spinal ischaemia, careful needle placement dorsal to the nerve root and the use of a non-particulate corticosteroid, like dexamethasone, are advocated.

[Guidance of axillary multiple injection technique for plexus anesthesia. Ultrasound versus nerve stimulation]. / Steuerung der axillären Multiinjektionstechnik zur Plexusanästhesie. Ultraschall vs. Nervenstimulation.

BACKGROUND: Ultrasound guidance is still a young method in regional anesthesia when compared to nerve stimulation and only a few studies exist comparing these two techniques in an axillary multiple injection approach. AIM: This prospective, randomized, observer-blinded study compared an ultrasound-guided (SONO) quadruple injection axillary block (out of plane, perineural) with a nerve stimulation-guided (STIM) triple injection axillary block for upper limb surgery. MATERIAL AND METHODS: A total of 60 patients were randomized to either the SONO (n = 30) or STIM (n = 30) group. For the block 40-50 ml mepivacaine 1.5 % (plexus) and 5-10 ml mepivacaine 0.5 % (subcutaneous in the medial skin of the arm) was used. Anesthesia time was recorded as the primary end point. After evaluation of block-related pain using a visual analog scale (VAS) a blinded observer tested sensory and motor function of the median nerve (MED), ulnar nerve (ULN), radial nerve (RAD), musculocutaneous nerve of the upper limb (MUC) and medial cutaneous nerve of the forearm (CAM) at defined times. The main outcome variable was onset time (defined loss of sensory/motor function). RESULTS: No differences were observed between the groups in terms of onset time (single nerves 10-20 min, plexus 20-25 min) and success rate (SONO 90 %, STIM 89 %). Patient satisfaction as measured by block-related pain score (VAS 2 cm), complications (vascular puncture SONO 7 %, STIM 11 %; paresthesia SONO 21 %, STIM 22 %) and patient acceptance (SONO 92 %, STIM 91 %) showed no differences. Performance time was shorter in the SONO group (6.68 ± 1.72 min vs. 8.05 ± 2.58, p = 0.02). CONCLUSION: Nerve stimulation-guided axillary plexus blocks performed by trained anesthesiologists may result in similar onset times and success rates compared to ultrasound-guided blocks.

Effects of mepivacaine 2% with epinephrine in the cardiovascular activity of patients undergoing third molar surgery: a prospective clinical study.

BACKGROUND: Cardiovascular effects of epinephrine, especially on blood pressure (BP) and heart rate (HR), have been well documented. When present in dental local anesthetic solutions, epinephrine concentration ranges from 5 to 20 µg/mL. Doses less than 200 µg are recommended to be clinically safe. OBJECTIVES: This study investigated the effects of the anesthetic solution of mepivacaine (2%) with epinephrine (10 µg/mL) in cardiovascular activity (HR and BP). METHODS: Twenty-six patients underwent outpatient surgery for the removal of 2 unilateral (group I, n = 15) or 4 (group II, n = 11) third molars in a single session, being injected 5.4 and 10.8 mL of anesthetic solution, equivalent to 54 and 108 µg of epinephrine, respectively. The cardiovascular activity was monitored by cardioscope during the experimental period of 2 hours. Heart rate and BP were measured at the intervals of 0, 5, 10, 15, 20, 30, 40, 60, 90, and 120 minutes after anesthetic injection. RESULTS: After application of 2-way analysis of variance test, comparison between groups was not statistically significant for HR (P = 0.1388), systolic BP (P = 0.0228), and diastolic BP (P = 0.9846). However, patients from group II presented significantly greater sway in HR (P < 0.0001), systolic BP (P = 0.0169), and diastolic BP (P < 0.0001) in the course of 2 hours. CONCLUSIONS: Blood pressure did not present significant alterations after a local injection of 54 or 108 µg of epinephrine during surgery to remove 2 or 4 third molars. Although without significance, HR was more elevated in the 108-µg dose of epinephrine during the removal of 4 third molars.

Complications of single-injection ultrasound-guided infraclavicular block: a cohort study.

INTRODUCTION: In recent studies on ultrasound-guided infraclavicular block (ICB), the authors have favoured a single injection posterior to the axillary artery rather than multiple injections; however, procedural complications and success rates associated with single-injection ultrasound-guided ICB are not well known. We undertook an observational study to evaluate the success rates of experienced and non-experienced operators performing ICBs and to identify the complications associated with ultrasound-guided single-injection ICB. METHODS: We conducted an observational cohort study of all ultrasound-guided single-injection ICBs performed over a two-year period (2008-2010). We identified the subjects for our study using a local database and excluded patients younger than 18 yr and those who received a continuous ICB. Complications (non-neurological and neurological) and ICB success rates were the primary and secondary end points, respectively. We collected the following data from patients' charts: patient demographics, types of complications and their respective frequencies, and the experience of the clinician performing the ICBs, and we identified potential late complications by telephone interview. Using a seven-point Likert scale, two experts in regional anesthesia evaluated the likelihood of a relationship between the identified neurological signs or symptoms and the ICB. A neurologist then evaluated the complications identified as being potentially related to the ICB. Summary data were collated, and 95% confidence intervals (CI) were calculated. RESULTS: We reviewed 627 ICB procedures, and 496 (79%) patients received telephone interviews. Most patients were males who had undergone either plastic or orthopedic surgery. Mepivacaine 1.5% was used in 96% of cases with a median volume of 30 mL [interquartile range 30-38]. We identified 131 cases of neurological signs or symptoms. Four cases were retained as possible links to the ICB, but they underwent complete resolution of symptoms at the time of evaluation. Two possible cases of local anesthetic toxicity were observed. There was a 93% success rate (95% CI 91 to 95) and the results were comparable between the experienced and the non-experienced operators (94% vs 93%, respectively). DISCUSSION: We observed few complications associated with a single-injection ultrasound-guided ICB and a high success rate regardless of the operator's expertise. The technique appears to be reliable, easy to perform, and safe.

Amnesia and pain relief after cardiopulmonary resuscitation in a cancer pain patient: a case report.

The mechanism of chronic pain is very complicated. Memory, pain, and opioid dependence appear to share common mechanism, including synaptic plasticity, and anatomical structures. A 48-yr-old woman with severe pain caused by bone metastasis of breast cancer received epidural block. After local anesthetics were injected, she had a seizure and then went into cardiac arrest. Following cardiopulmonary resuscitation, her cardiac rhythm returned to normal, but her memory had disappeared. Also, her excruciating pain and opioid dependence had disappeared. This complication, although uncommon, gives us a lot to think about a role of memory for chronic pain and opioid dependence.

Incidence and effects of unintentional intraneural injection during ultrasound-guided subgluteal sciatic nerve block.

BACKGROUND: The present study was conducted to determine the incidence of unintentional intraneural injection during ultrasound-guided subgluteal sciatic nerve block using a low-frequency transducer. We also observed the effects of intraneural injection using ropivacaine and mepivacaine. METHODS: Enrolled in the study were 325 patients undergoing arthroscopic knee surgery, who each received a subgluteal sciatic nerve block under ultrasound guidance using 1.5% mepivacaine with 1:400,000 epinephrine or 0.5% ropivacaine. A block needle was inserted in-plane with the ultrasound transducer (5-2 MHz curved array) and advanced slowly under real-time ultrasound guidance until it was positioned immediately adjacent to the nerve. Twenty milliliters of either anesthetic was then injected to produce a circumferential spread. An ultrasound video was recorded and used to examine whether the local anesthetic was injected intraneurally. Sensory and motor blockade was evaluated for 30 mins after completion of the block. Duration of the block and any neurologic complications were also examined. RESULTS: Intraneural injection was detected in 46 patients (16.3%; 95% confidence interval, 12.3%-20.3%). Onset of sensory and motor blockade was significantly faster in patients with intraneural injection than those without either mepivacaine or ropivacaine. Duration of sensory blockade was similar between patients with and without intraneural injection. No patient developed postoperative neurologic complications. CONCLUSIONS: Unintentional intraneural injection occurred at an incidence rate of 16.3% for the ultrasound-guided subgluteal approach to the sciatic nerve. Intraneural injection of mepivacaine or ropivacaine hastened the onset of blockade but did not affect block duration, and it did not result in clinical neural injury in our small sample of patients.

Retinal vascular occlusion after vitrectomy with retrobulbar anesthesia-observational case series and survey of literature.

BACKGROUND: Severe postoperative loss of vision has been occasionally reported as a rare complication of retrobulbar anesthesia, and several possible causes have been proposed in the literature. In this work, our own and other investigators' experiences with these complications are surveyed with a view to identifying its pathophysiology. PATIENTS: This observational case series refers to six patients who presented during a 3-month period with occlusion of either the central artery itself (n = 3) or a branch thereof (n = 3) 2-14 days after uneventful vitreoretinal surgery following retrobulbar anesthesia with a commercial preparation of mepivacaine (1% Scandicain®, Astra Chemicals, Sweden) containing methyl- and propyl parahydroxybenzoate as preservatives. RESULTS: Three of the patients carried risk factors, which were medically controlled. In three individuals, vasoocclusion was observed after a second vitreoretinal intervention, which was performed 3-12 months after uneventful primary surgery. Good visual recovery was observed in only one instance. CONCLUSIONS: In patients who were anesthetized with preservative-free mepivacaine, no vasoocclusion occurred. In individuals who were anesthetized with mepivacaine containing the preservatives methyl- and propyl parahydroxybenzoate, a tenfold increase in the incidence of eyes requiring re-operation was documented, with a 2- to 14-day lapse in the onset of vasoocclusion. These findings reveal a possible implication of preservatives contained in the local anesthetic solution for the vasoocclusive events. Due to this potential hazard, the use of preservative-free preparations of local anesthesia in ocular surgery is emphasized in order to prevent this sight-threatening complication.