Ultrasound-guided Sciatic Nerve Research Articles

The effect of sciatic nerve block on sciatic nerve depth and pain level in patients with ankle fracture based on different approaches under ultrasound guidance.

To investigate the clinical efficacy of using different approach sciatic nerve blocks on the sciatic nerve depth and pain degree in patients with ankle fracture. A retrospective analysis was conducted on 151 patients with ankle fractures who were admitted to the hospital from May 2020 to May 2023. The patients were divided into a control group (n=76) using the greater trochanteric plane approach (GTA) and an observation group (n=75) using the suprapopliteal approach (PA). Perioperative related indexes, pain levels, muscle strength, hemodynamic indexes, and adverse reactions were compared between the two groups. There was no significant difference in operation time between the two groups. The nerve block operation time and onset time were lower in the observation group, while the maintenance time of nerve block was higher in the observation group(P<0.05). The visual analogue scale (VAS) scores at 2h, 12h, and 24h postoperatively were lower in the observation group. Muscle strength of the posterior femoral muscle group was significantly better in the observation group at 8h after surgery. Hemodynamic indexes were lower in the observation group at 15minutes and 30minutes after anesthesia. The total incidence of adverse reactions was lower in the observation group compared to the control group. Ultrasound-guided sciatic nerve block using the suprapopliteal approach in patients with ankle fractures can help stabilize muscle strength and hemodynamics, alleviate pain symptoms, and avoid motor block and adverse reactions. This approach is recommended for adoption.

Ultrasound-Guided Nerve Blocks for Leg Amputation in High-risk Patients under Antithrombotic Therapy: A Report of Two Cases and Review of Literature

Patients with complex comorbidities under antithrombotic therapy are a real challenge for anesthesiologists because of general and neuraxial anesthesia high risks. Perineural anesthesia allows high quality intraoperative conditions for fragile patients and provides excellent postoperative results. Ultrasound guided superficial nerve blocks were defined to be with low risk of bleeding and seems to be a safe anesthetic option for patients under antithrombotic therapy. Through two cases of leg amputation performed under ultrasound-guided femoral and sciatic nerve blocks we discuss the interest and the practicability of this anesthetic technique in such patients.

Surgeon-administered ultrasound-guided combined popliteal sciatic nerve and adductor canal block in fixation of trimalleolar fracture

Introduction: Combined popliteal sciatic nerve and adductor canal block under ultrasound guidance has been described as a safe and effective mean of regional anesthesia for foot and ankle surgery. Limited studies have shown its effectiveness while performed by surgeons. This study aims to assess the effectiveness and safety for this mode of regional anesthesia while carried out by orthopedic surgeons. Method: Patients presented to our unit with trimalleolar fracture of ankle who underwent operation under surgeon-administered ultrasound-guided combined popliteal sciatic nerve and adductor canal block were evaluated in this study. A total of 13 patients with mean age of 57.8 were included. Data regarding the diagnosis, pattern of injuries, comorbidities in American Society of Anesthesiologists Classification, duration of operation, blood loss, intraoperative pain control in visual analog scale (VAS), degree of motor blockage, postoperative pain control and hospital length of stay were collected and evaluated. Result: All patients experienced complete anesthesia with VAS 0 and complete motor blockage throughout the operation. Average operative time was 179 min. Postoperative pain control was satisfactory. There was no regional anesthesia related complication arise. Conclusion: Surgeon-administered ultrasound-guided combined popliteal sciatic nerve and adductor canal block is a safe and effective mean to provide anesthesia for trimalleolar fracture fixation according to our experience.

Dexamethasone as a perineural adjuvant to a ropivacaine popliteal sciatic nerve block for pediatric foot surgery: a randomized, double-blind, placebo-controlled trial

BackgroundThis study assessed the effect of perineural dexamethasone on block duration, opioid requirement, blood glucose levels, and stress response to surgery as measured by the neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte...

ULTRASOUND-GUIDED ANTERIOR SCIATIC NERVE BLOCK AND FEMORAL NERVE BLOCK FOR MANAGEMENT OF ABOVE KNEE AMPUTATION IN A POSTOPERATIVE TIBIA EXTERNAL FIXATION PATIENT WITH SEPTIC SHOCK: A CASE REPORT

This case report describes the successful management of a 50-year-old male patient with septic shock following a right tibia external fixation surgery, who was subsequently scheduled for an above knee amputation. The patient presented with hypoxia, hypotension, and required intubation in intensive care unit. In addition, the patient was placed on a noradrenaline infusion due to persistent hypotension. Laboratory investigations revealed thrombocytopenia, elevated procalcitonin levels, increased C-reactive protein, elevated myoglobin levels, and elevated D-dimer levels. Given the patients critical condition, an ultrasound-guided anterior sciatic nerve block and femoral nerve block were performed for surgery. This case report discusses the successful perioperative management of the patients septic shock and the potential role of regional nerve blocks in such critically ill patients.

Ultrasound-guided sciatic nerve block injections in barred owl (Strix varia) cadavers

ObjectiveTo describe an ultrasound-guided approach to the sciatic nerve and the distribution of nerve staining using two injectate volumes of dye in barred owls. Study designDescriptive, randomized, assessor-blinded, cadaveric study. AnimalsTwelve barred owl cadavers. MethodsThe sciatic nerve was visualized with a 13-6 MHz linear ultrasound probe placed on the medial aspect of the proximal femur in barred owl cadavers. A needle was inserted at the proximal caudal thigh, and cranially advanced in-plane until the tip was immediately adjacent and ventral to the sciatic nerve. Eleven owls were injected bilaterally with a 1:1 solution of 1% methylene blue and 0.5% ropivacaine, with high-volume (HV; 0.4 mL kg–1) and low-volume (LV; 0.2 mL kg–1) treatments. Nerve staining ≥ 1 cm circumferentially was determined by dissection 15 minutes post-injection. The coelom was then opened to inspect for aberrant dye spread. In one barred owl cadaver, a 1:1 solution of 1% methylene blue and 74% ioversol contrast was injected, and computed tomography was performed immediately before and 15 minutes after injection for evaluation of injectate spread. ResultsThe HV treatment (0.4 mL kg–1) resulted in successful nerve staining in 100% of injections, whereas the LV treatment (0.2 mL kg–1) resulted in successful nerve staining in 91% of injections. There was no leakage of injectate into undesired locations (e.g. coelomic cavity) in any cadaver. Conclusions and clinical relevanceIn barred owls, the sciatic nerve can be visualized with ultrasound and injecting a ropivacaine/dye solution under ultrasound guidance successfully stained the sciatic nerve in the majority of cases. This technique holds potential for providing analgesia distal to the stifle joint; however, further investigations are necessary to evaluate its practical application in a clinical setting.

Ultrasound-guided sciatic nerve block in a patient with sciatic neuropathy associated with uterine myoma: a case report

Ultrasound-guided sciatic nerve block in a patient with sciatic neuropathy associated with uterine myoma: a case report

Ultrasound-Guided Sciatic Nerve Hydrodissection Can Improve the Clinical Outcomes of Patients with Deep Gluteal Syndrome: A Case-Series Study.

Deep gluteal syndrome (DGS) is caused by sciatic nerve entrapment. Because fascial entrapment neuropathies may occur in multiple locations, ultrasound-guided nerve hydrodissection is a key component of DGS treatment. In this study, we examined the clinical outcomes of patients with DGS undergoing ultrasound-guided sciatic nerve hydrodissection. A 10 mL mixture consisting of 5% dextrose, 0.2% lidocaine (Xylocaine), and 4 mg betamethasone (Rinderon) was used for nerve hydrodissection. Clinical outcomes were evaluated using Numeric Rating Scale (NRS) scores of pain, the proportion of patients with favorable outcomes (reduction of ≥50% in pain), the duration for which patients exhibited favorable outcomes (percentage of follow-up duration), and the occurrence of major complications and minor side effects. A total of 53 patients were consecutively included and followed up for 3 to 19 months. After the initial injection, the NRS scores significantly improved at 1 week, 1 month, 3 months, and the final follow-up. Specifically, 73.6%, 71.7%, 64.2%, and 62.3% of the patients exhibited favorable outcomes at 1 week, 1 month, 3 months, and the final follow-up, respectively. The median duration for which the patients exhibited favorable outcomes was 84.7% of the follow-up period. Three patients (5.7%) experienced transient dizziness and vomiting, which resolved without further treatment. No vessel or nerve puncture was observed. Overall, ultrasound-guided sciatic nerve hydrodissection is a safe procedure that mitigates the pain associated with DGS. To achieve favorable outcomes, three consecutive injections 3 weeks apart are required.

Ultrasound-Guided Sciatic Nerve Block vs. Caudal Analgesia in Cerebral Palsy Undergoing Lower Limb Surgeries

Background: Continuous advancements in ultrasound (US)-guided neuraxial and peripheral nerve blocks (PNB) have allowed the safe and successful use of these blocks as adjuvants to general anesthesia in pediatric patients. Objectives: This study was designed to compare the analgesic efficacy of 2 US-guided regional techniques, caudal epidural block (CEB) and subgluteal sciatic nerve block (SNB), in children with cerebral palsy (CP). Methods: The current randomized comparative study was conducted on 30 patients with spastic CP aged 2-12 years who were scheduled for unilateral lower limb multilevel soft tissue corrective surgeries, randomly distributed using a computerized program into 2 equal groups. The CEB group received a US-guided caudal block, and the SNB group received a US subgluteal sciatic nerve block. The time to the first postoperative analgesia requirement (primary outcome), postoperative pain score, total postoperative analgesic consumption, and perioperative complications (secondary outcomes) were assessed in both groups. Results: The duration of postoperative analgesia was significantly longer in patients of the SNB (14.65 ± 3.08 h) than in the CEB group (5.93 ± 1.68 h). The postoperative pain scores recorded at 6th-12th h and the postoperative 24-h rescue analgesic consumption were significantly lower in the SNB compared to the CEB group. Conclusions: Ultrasound-guided subgluteal sciatic nerve block is a safe and effective alternative to US-guided caudal analgesia in pediatric patients with spastic CP scheduled for lower limb surgeries, with longer postoperative analgesia and similar perioperative safety profiles.

Ultrasound-guided sciatic nerve block in Wistar rat cadavers: Relevant anatomy and injection distribution

ObjectiveTo investigate the feasibility of an ultrasound-guided sciatic nerve block by describing the sonoanatomy and comparing the distribution of two volumes of bupivacaine dye solution for nerve staining. Study designRandomized, experimental, assessor-blinded cadaveric study. AnimalsA total of 40 adult female Wistar rat cadavers. MethodsAfter studying the sonoanatomy of the sciatic nerve and adjacent structures using a high-resolution linear transducer (19–5 MHz), rat cadavers were randomly divided into two groups that were administered either 0.1 mL (group 0.1) or 0.2 mL (group 0.2) of bupivacaine dye solution per nerve, delivered via an in-plane technique. The extent of nerve staining was subsequently evaluated following dissection. Statistical analysis consisted of assessing data distribution using the Shapiro–Wilk test, followed by paired t-tests for continuous data, Mann–Whitney U test and McNemar’s test for categorical data. Statistical significance was defined as p < 0.05. ResultsThe sciatic nerve was identified bilaterally as a double ellipsoid-shaped image, surrounded by a hyperechoic fascia separating the biceps femoris from the adductor muscle. The hypoechoic structure formed by the bupivacaine dye solution around the nerve was effectively visualized using ultrasound imaging. Sciatic nerve staining was successfully achieved in all pelvic limbs, with dye spread of 4.82 ± 1.55 mm and 5.47 ± 2.18 mm in groups 0.1 and 0.2, respectively (p = 0.128). Conclusions and clinical relevanceThis study achieved a detailed understanding of the sonoanatomy of the sciatic nerve and its adjacent structures, highlighting the feasibility of the ultrasound-guided technique for injection in Wistar rats. Furthermore, the results show a comparable distribution of dye solution in both groups. Use of the ultrasound-guided sciatic nerve block technique in rats not only exhibits substantial potential for regional anesthesia but also opens avenues for translational studies.

Quantitative assessment of ultrasound-guided sciatic nerve block - A comparison of a single-point versus two-point injection technique: A randomised controlled, double-blinded trial.

Sciatic nerve block at the popliteal level for lower limb procedures provides unpredictable success rates even with ultrasonographic (USG) guidance. This study aimed to compare USG-guided single-point versus two-point injection techniques. Sixty patients posted for foot surgeries under USG-guided sciatic nerve block were randomised into Group Single Point, receiving a single injection of 20 mL of 1.5% lignocaine with adrenaline just proximal to the sciatic nerve bifurcation, and Group Double Point, receiving two injections of 10 mL of 1.5% lignocaine with adrenaline, one at the point similar to the first group and a second injection 6 cm above the first point. Sensory blockade onset, time to complete sensory blockade, time to complete motor blockade, length of the nerve exposed and analgesia duration were evaluated. Statistical analysis was performed with Statistical Package for the Social Sciences (SPSS) statistics version 20 software. Double-point injection technique showed a significantly faster time to complete motor blockade [14.46 (9.93) min], increased length of nerve exposed to local anaesthetic [23.23 (7.209) cm] and extended duration of analgesia [420.40 (99.34) min] compared to the single-point injection technique [20.89 (12.62) min, 18.78 (5.95) cm and 344.28 (125.97) min, respectively]. The onset of sensory blockade and the time to complete sensory blockade were comparable between the two groups. USG-guided popliteal sciatic nerve block with a double-point injection technique does not significantly shorten the time to complete the sensory block. However, the time to complete motor nerve block and duration of analgesia are prolonged significantly, which may be clinically beneficial for postoperative analgesia.

Evaluation of a New Method of Sciatic Nerve Block: A Prospective Pilot Study.

The location of the sciatic nerve deep within the thigh tissue makes it challenging to locate while the patient is in a supine position. The posterior intermuscular septum of the thigh, which encircles the posterior surface of the adductor magnus muscle (AMM), is where the sciatic nerve is located. Our hypothesis was that administering local anesthetic injections into this area could block the sciatic nerve. Therefore, our aim was to evaluate the effectiveness of sciatic nerve block achieved by injecting local anesthetic into the posterior intermuscular septum of the thigh, named the AMM approach. Twenty-six patients undergoing total knee arthroplasty were included in the study. We performed an ultrasound-guided sciatic nerve block by injecting 20 mL of 0.25% ropivacaine into the posterior surface of the adductor magnus muscle, using the AMM approach. Additionally, we administered a femoral nerve block with 20 mL of 0.4% ropivacaine. We assessed the sensory and motor effects of the blockade in the operated lower limb and recorded postoperative pain scores at 0, 4, 8, 12, 24, and 48 hours after the operation. The AMM approach successfully block the sciatic nerve in all 26 patients. The onset of the sensory and motor blockades was achieved within 5.4 ± 1.9 min and 8.7 ± 3.5 min, respectively. We achieved a satisfactory position with the first puncture in 19 of 26 patients (73.1%). The muscle strength of the tibialis anterior immediately after surgery was 4 (ranging from 2 to 5). Additional rescue analgesics were required in 5 of the 26 patients (19.2%) during the first 24 hours postoperatively. The AMM approach is an innovative and effective method for sciatic nerve block. When combined with simultaneous femoral nerve block in patients undergoing total knee arthroplasty, it provides a useful analgesic treatment option.

Comparison of Ultrasound-Guided Anterior and Posterior Approaches to Sciatic Nerve Block for Lower Limb Surgeries: A Randomised Clinical Study

Introduction: Sciatic nerve block is used for anaesthesia and analgesia in lower limb surgeries. The anterior approach to the sciatic nerve is rarely performed due to unreliable anatomical surface markings. Aim: To compare the anterior and posterior approaches to sciatic nerve block in terms of patient comfort and technical difficulty. Materials and Methods: This randomised clinical study was conducted at the Department of Anaesthesiology, BLDE (Deemed to be University) Shri BM Patil Medical College, Hospital and Research Centre, Bijapur, Karnataka, India. A total of 84 patients who underwent lower limb surgeries from November 2020 to August 2022 were included. Informed consent was obtained, and patients were randomised into two groups-Group-A and Group-P-using the card method. Ultrasound-guided sciatic nerve block was performed using the anterior approach in Group-A and the posterior approach in Group-P. Sensory and motor blockade, time to perform the block, number of attempts, duration of analgesia, and patient satisfaction were recorded. Statistical analysis was performed using the Chi-square test, Analysis of Variance (ANOVA), student t-test, and the results were represented in tables. Results: The median age in Group-A was 42.95±12.69 years, and in Group-P was 43.95±8.68 years. Males were higher in number with 26 (31%) in Group-A and 23 (27%) in Group-P, respectively. Patient satisfaction, duration of analgesia (10.3±3.5 years Group-P and 10.5±4.0 years Group-A), onset of sensory (11.85±7.35 years Group-P and 9.53±5.40 years Group-A), and motor blockade (18.67±7.05 years Group-P years and 17.82±5.70 years Group-A) were similar in both groups. The number of attempts (2.85±0.90 years Group-P and 3.05±0.91 years Group-A) and time taken for performing the sciatic nerve block (6.75±1.10 years Group-P and 7.44±1.00 years Group-A) was higher in the anterior approach compared to the posterior approach. Conclusion: Although both approaches to sciatic nerve block are equally effective, this study concludes that the posterior approach is simpler to perform, requires less time, and provides better patient comfort and satisfaction. Ultrasound-guided posterior sciatic nerve block offers effective anaesthesia and excellent post-operative analgesia.

Comparison of Safety and Efficacy of Unilateral Spinal Anaesthesia and Ultrasound-guided Sciatic Femoral Nerve Block in below Knee Surgery: A Randomised Clinical Study

Introduction: With modern advances, Ultrasonography (USG)- guided regional block techniques have improved nerve blockade with lesser drug usage and maximum safety for patient care. The widely appreciated outpatient surgical care has compelled us to apply the fastest and safest anaesthesia technique. For lower limb surgeries, USG-guided Sciatic Femoral Nerve Block (SFNB) is an emerging alternative to Spinal Anaesthesia (SA). Aim: To compare the safety and efficacy of both techniques in terms of haemodynamic stability, quality of block, and postoperative analgesia. Materials and Methods: A randomised double-blind study conducted at GCS Medical College, Hospital, and Research Centre, Ahmedabad, Gujarat, India, on 80 patients aged 18 to 70 years of either sex, with American Society of Anaesthesiology (ASA) Grade 1 to 3, undergoing below-knee surgeries was divided into two groups. Group A received USA with 1.5 mL hyperbaric inj. ropivacaine 0.75%, and Group B received USGguided SFB with inj. ropivacaine 0.5% 30 mL (15 mL for sciatic nerve and 15 mL for femoral nerve block). Preparation Time (PT), Surgical Anaesthesia Time (SAT), haemodynamic changes, quality of block, Longevity of Anaesthesia (LoA), time of first rescue analgesia, time of spontaneous urination, readiness to discharge, and patient satisfaction were recorded. The statistical analysis was carried out using Statistical Package for Social Sciences version 23.0 (SPSS Inc., Chicago II, USA). The p-value was derived by unpaired t-test and Chi-square test. Results: PT and SAT were higher in Group B (12.10±2.02 mins and 15.74±1.58 mins) than in Group A (6.15±1.12 mins and 8.23±1.45 mins). LoA time and time to first rescue analgesic were higher in Group B (284.10±54.44 mins and 265.71±33.69 mins) than in Group A (138.75±23.30 mins and 132.40±17.41 mins). Time to first spontaneous urination and readiness to discharge were shorter in Group B (136.42±18.40 mins and 158.39±10.78 mins) than in Group A (162.20±26.54 mins and 181.53±18.18 mins). Haemodynamic stability was excellent in both groups with no significant fluctuation. Motor blockade of Bromage 3 grade was achieved in 40 and 38 patients in Group A and B, respectively. The development of VAS score &gt;3 was faster in Group A than in Group B (35 versus 2) at the end of three hours. No adverse events were observed in any patient. Conclusion: USG-guided SFB offers a safe and efficient alternative to Unilateral SA (USA) with satisfactory blockage, stable haemodynamics, and better postoperative analgesia for below-knee surgeries.

Examining the impact perceptual learning artificial-intelligence-based on the incidence of paresthesia when performing the ultrasound-guided popliteal sciatic block: simulation-based randomized study

ObjectiveTo explore the impact of artificial-intelligence perceptual learning when performing the ultrasound-guided popliteal sciatic block.MethodsThis simulation-based randomized study enrolled residents who underwent ultrasound-guided sciatic nerve block training at the Department of Anesthesiology of Beijing Jishuitan Hospital between January 2022 and February 2022. Residents were randomly divided into a traditional teaching group and an AI teaching group. All residents attended the same nerve block theory courses, while those in the AI teaching group participated in training course using an AI-assisted nerve identification system based on a convolutional neural network instead of traditional training.ResultsA total of 40 residents were included. The complication rates of paresthesia during puncture in the first month of clinical sciatic nerve block practice after training were significantly lower in the AI teaching group than in the traditional teaching group [11 (4.12%) vs. 36 (14.06%), P = 0.000093]. The rates of paresthesia/pain during injection were significantly lower in the AI teaching group than in the traditional teaching group [6 (2.25%) vs. 17 (6.64%), P = 0.025]. The Assessment Checklist for Ultrasound-Guided Regional Anesthesia (32 ± 3.8 vs. 29.4 ± 3.9, P = 0.001) and nerve block self-rating scores (7.53 ± 1.62 vs. 6.49 ± 1.85, P < 0.001) were significantly higher in the AI teaching group than in the traditional teaching group. There were no significant differences in the remaining indicators.ConclusionThe inclusion of an AI-assisted nerve identification system based on convolutional neural network as part of the training program for ultrasound-guided sciatic nerve block via the popliteal approach may reduce the incidence of nerve paresthesia and this might be related to improved perceptual learning.Clinical trialCHiCTR2200055115, registered on 1/ January /2022.

Effect of perioperative sciatic nerve block on chronic pain in patients undergoing below-knee amputation: A randomised controlled trial

Many pain syndromes such as chronic phantom limb pain (PLP) and stump pain (SP), involving nociceptive and neuropathic pain, develop after amputation. Recent literature suggests that the use of regional blocks reduces repeated stimulation of transected nerve roots and thus prevents central sensitisation. This randomised, double-blind study was conducted to evaluate the effect of pre-emptive ultrasound-guided single-shot lateral sciatic nerve block on the occurrence of chronic pain at six months after traumatic below-knee amputation. Thirty patients undergoing traumatic lower limb amputation under general anaesthesia were randomised into two groups: Group B received sciatic nerve block pre-emptively using ultrasound with 20 ml of 0.75% ropivacaine, whereas group C received 20 ml of normal saline. Follow-up of patients was done till six months post-amputation. The primary objective was to assess the occurrence of chronic pain at six months. Pain at 15 days and one month after surgery, post-operative morphine consumption and post-operative nausea and vomiting (PONV) were the secondary outcomes assessed. The occurrence of PLP at six months was comparable in the two groups, group B (46.7%) and C (66.7%). None of the patients developed SP at six months. Median intensities of phantom pain were 1.0 (range, 1-2.0) versus 1.0 (range, 1-2.0) (P = 0.36), and median intensities of SP 2 (range, 2-3.0) versus 3 (range, 2-3.0) (P = 0.39) at 1 month. Pre-emptive sciatic nerve block did not decrease the occurrence or severity of chronic pain after traumatic below-knee amputation.

248 Ultrasound-Guided Transgluteal Sciatic Nerve Block in Emergency Department Patients With Sciatic Radiculopathy: A Multicenter Prospective Study

Acute-on-chronic pain secondary to sciatica is a common emergency department (ED) presentation and often leads to loss of work, decreased function, and emotional distress. The transgluteal sciatic nerve block (TGSNB) is used by anesthesiologists for chronic, acute, and perioperative sciatic nerve pain. The objective of this study is to assess the efficacy and safety of ED performed TGSNB for acute sciatic radiculopathy.

Block duration is substantially longer with a liposomal suspension of bupivacaine than with 0.5% bupivacaine HCl potentiated with dexmedetomidine following an ultrasound-guided sciatic nerve block in Beagles

To compare the duration of bupivacaine liposome suspension in the dog with that of bupivacaine and dexmedetomidine following a perineural injection. 8 healthy Beagles. The left sciatic nerve of each dog was randomly assigned to an ultrasound-guided perineural injection with either bupivacaine liposome suspension (BLS) or with 0.5% bupivacaine with dexmedetomidine (1 µg/mL) (BUP-DEX). The contralateral nerve was assigned to the alternate agent. The sensory, motor, and proprioceptive functions were evaluated before the injection (baseline) and at 4, 10, 24, 48, 72, and 96 hours. The block in 1 limb in the BLS treatment appeared to have failed (data set excluded). The motor scores of 2 individuals could not be evaluated leaving 5 limbs to evaluate in the BLS treatment and 6 in the BUP-DEX. A total of 6 out of 7 limbs in the BLS achieved a complete sensory block. In 3 out of 5 treatments with BLS, motor block was only partial and in 2 not apparent at all. Proprioceptive block was partial in 5 out of 7 dogs in the BLS treatment. All functions were still completely obliterated at 10 hours in 6 cases in treatment BUP-DEX. All functions were restored in all cases by 96 and 24 hours after administration of BLS and BUP-DEX, respectively. The blockade characteristics of bupivacaine liposome suspension were effective and long lasting. Motor and proprioceptive deficits may be inconsistent over time.

Post-operative nausea and vomiting (PONV) observed in a clinical study designed to assess the analgesic effects of intravenous and subcutaneous methadone in dogs

Opioids are a key component of multimodal analgesia. Methadone is licensed in Europe for IV, IM and SC use in dogs despite there being no published studies assessing the analgesic efficacy of SC administration. Our intention was to compare the analgesic effect of IV or SC methadone. Fifteen dogs presenting for stifle surgery were administered 0.4 mg/kg methadone IV followed by a randomised 0.0.4 mg/kg methadone IV or SC dose 3 h later. All dogs received ultrasound-guided sciatic and saphenous nerve blocks with bupivacaine prior to surgery. This protocol resulted in opioid adverse effects (hypersalivation, vomiting and/or regurgitation) in 5/15 dogs (33%). Thus, in consultation with the ethical review committee, an otherwise identical protocol using a revised 0.2 mg/kg methadone dose was implemented. In the next three dogs studied, similar opioid adverse effects were found in all three dogs and the study was terminated. This paper highlights the potential for post operative nausea and vomiting (PONV), which may have been induced by methadone when used in combination with efficacious locoregional anaesthesia.

Estimation of the minimum effective volume of 0.5% bupivacaine for ultrasound-guided popliteal sciatic nerve block in diabetic patients with neuropathy.

Background and Aims:The safety of conventional regional nerve block techniques in patients with established neuropathies, such as diabetic peripheral neuropathy (DPN), is still unclear. We designed this prospective dose finding study to identify the minimum effective local anaesthetic volume of 0.5% bupivacaine for ultrasound-guided subparaneural popliteal sciatic nerve block in 90% of DPN patients undergoing below-knee surgery (MELAV90).Methods:Fifty-three patients with diabetic peripheral neuropathy and scheduled for below knee surgical procedure received popliteal sciatic nerve block under ultrasound guidance. The initial local anaesthetic volume used was 10 ml of 0.5% bupivacaine. The subsequent local anaesthetic volume allocation was based on biased-coin-design. Accordingly, the local anaesthetic volume given to each subject was based on the block outcome of the previous patient. The study included patients prospectively until 45 successful blocks were obtained. The primary measurement was the minimum effective local anaesthetic volume resulting in a successful subparaneural popliteal sciatic nerve block in 90% of DPN patients. The MELAV90 was calculated using isotonic regression and a 95% confidence interval bootstrapping method.Results:The study included 53 patients to obtain 45 successful blocks. The MELAV90 of 0.5% bupivacaine was obtained at 5.85 ml (95% confidence interval, 5.72 to 6.22 ml). Eight patients needed supplemental anaesthesia to complete the surgery. No other complications were noted.Conclusion:For patients with diabetic peripheral neuropathy undergoing below-knee surgery, the MELAV90 of 0.5% bupivacaine for subparaneural popliteal sciatic nerve to achieve surgical anaesthesia was 5.85 ml.