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This study describes a transversal (TV) ultrasound-guided erector spinae plane (ESP) block technique over the transverse process of T12. And evaluates the distribution of the dye and affected nerves branches compared to a longitudinal (LNG) approach over the transverse process of T12 in canine cadavers. Secondly, it also compares de anatomy and dimensions of the transverse processes of T12 with T9 and T5. For this double-masked, cadaveric experimental study, 12 adult Beagle cadavers were injected with 0.6 mL/kg of dye/contrast. Spread was evaluated by computed tomography (CT) and dissection. Mean bodyweight was 9.76 (±0.59) kg. The TV and LNG approaches stained a median (range) of four (2-6) and three (1-6) medial branches of the dorsal rami of the spinal nerves, three (2-6) and three (2-5) lateral branches, and one (0-3) and one (0-4) ventral branches, respectively. Dye was detected in the epidural space in 55.6% and 66.7% of cases for the TV and LNG approaches, respectively (P=0.63). And in the ventral paravertebral compartment in 22.2% and lymphatics in 88.8% in both approaches. There were no statistical differences for the spread. The dorsolateral edge of the transverse process (TP) was not visible with CT at T12. The mean (±SD) length of the TP was significantly shorter at T12 [3.34 (±0.22)] mm, compared to T9 [6.08 (±0.47)] mm and T5 [5.93 (±0.62)] mm (P <0.001). This study showed similar distribution whether using a TV or LNG approach and differences in the anatomy and length of the T12 TP., Competing Interests: Conflict of interest statement None of the authors has any financial or personal relationships that could inappropriately influence or bias the content of the paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

During diagnostic evaluation of hindlimb lameness in horses the tibial nerve block is traditionally performed based on anatomical reference points, but it can be difficult to achieve effective local anaesthesia using this blind technique. Ultrasound (US)-guided injection could increase the accuracy of injection. The aim of this study was to compare the accuracy of both techniques. Twenty-one paired sets of cadaver hindlimbs were injected with 1 mL methylene blue using the blind or US-guided technique. There was no significant difference in stain width and length and in coloured nerve length between techniques. However, the successful rate of nerve staining was 85.7% and 47.6% for the US-guided and blind technique, respectively (P = 0.02; odds ratio 6.6; 95% confidence interval, 1.5-29.4). This study suggests that the US-guided technique is more accurate than the blind technique. However, in the treated sample, a single US-guided injection did not consistently result in nerve staining., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Veterinary regional anesthesia (RA) has been rapidly increasing in popularity over the last 10 years, as evidenced by the increasing amount of literature available and the continuous development of new techniques in small animals. The introduction of new technologies such as nerve stimulation and ultrasound (which increased the objectivity and precision of the procedure) and the promising beneficial perioperative effects conferred by RA are encouraging clinicians to incorporate these techniques in their daily perioperative anesthetic and analgesic animal care. However, there is a lack of consensus regarding outcomes when RA is used, as well as outcome comparisons between regional anesthetic techniques. Further large-scale clinical studies are still necessary. This article is the first part of a two-part review of RA in small animals, and its aim is to discuss the most relevant studies in the veterinary literature, where objective methods of nerve location have been used, and to illustrate in pictures the currently used techniques for providing RA to the thoracic limb and the thorax in small animals., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Increasing interest in using peripheral nerve blocks in small animals is evident, given the numerous studies published recently on this topic in important veterinary journals. Initially, research was focused on intraoperative analgesia to the pelvic limb, and several descriptions of lumbosacral plexus, femoral and sciatic nerve blocks have been described in studies. There is recent interest in developing techniques for somatosensory blockade of the abdominal wall. This article is the second part of a two-part review of regional anesthesia (RA) in small animals, and its aim is to discuss the most relevant studies in the veterinary literature, where objective methods of nerve location have been used, and to illustrate in pictures the currently used techniques for providing RA to the abdominal wall and the pelvic limb in small animals., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

The aim of this study was to develop and evaluate a procedure for equine pudendal nerve block using a peripheral nerve locator. In the first experiment, six ponies were used to determine the relationship between elicited muscle contractions (anal, perineal or both) and nerves serving the perineal region (pudendal, caudorectal and perineal nerves) when methylene blue dye was injected using the electrolocation technique. This experiment showed that the pudendal nerve was approached effectively when both anal and perineal twitch were elicited during electrolocation. In a second experiment, seven Thoroughbred horses were used to evaluate the appropriate volume of anaesthetic solution for the nerve block. Immediately after euthanasia, lidocaine/methylene blue solution was injected after positive electrolocation. A stained segment of 2 cm or more of the nerve was considered effective and this was evaluated after dissection. Both 10 and 20 mL per injection site resulted in effective nerve staining. Finally, pudendal nerve block was performed and evaluated in 27 horses admitted for selected reproductive surgical procedures including perineoplasty, urethroplasty, clitorectomy in mares and penile examination, phallectomy and urethrostomy in geldings. Surgical time varied from several minutes to 3 h. The choice between lidocaine, mepivacaine or bupivacaine was based on the duration of analgesia required. In mares and males, a volume of 20 mL and 10 mL, respectively, was injected per site. The use of a peripheral nerve stimulator-guided pudendal nerve block is a feasible, safe and reliable alternative for both epidural and general anaesthesia, to provide peri-operative analgesia in clinical equine patients undergoing specific reproductive surgeries., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

A prospective, randomised, blinded, case-controlled clinical study was designed using client-owned dogs undergoing unilateral pelvic limb orthopaedic surgery, to determine the effect on induced motor activity by electrical stimulation of the sciatic nerve distal to the site of local anaesthetic administration. Dogs were administered 0.5% bupivacaine either extradurally or via a femoral and transgluteal sciatic electrolocation-guided nerve block prior to pelvic limb surgery. Motor response to electrical stimulation of branches of the sciatic nerve was tested and the minimum current required to induce muscle twitch was recorded prior to bupivacaine administration. Provided sensory blockade had been deemed successful intraoperatively, testing was repeated postoperatively, with each dog acting as its own control. Paired t-tests were performed to compare pre- and postoperative minimum currents. Eleven dogs administered extradural and 11 dogs administered femoral and sciatic perineural bupivacaine were eligible for post-operative testing. All dogs displayed normal motor response to electrical stimulation of the sciatic nerve at both sites tested before and after bupivacaine administration. There was no significant difference in the minimum current required to induce muscle twitch between pre- and post-operative testing (P = 0.31 sciatic site, P = 0.36 peroneal site), nor between the two groups using different loco-regional anaesthetic techniques (minimum P = 0.13). This study shows that stimulation of the sciatic nerve distal to the site of bupivacaine administration induces motor activity, despite adequate sensory blockade. This is relevant in surgical cases where mechanical stimulation of the sciatic nerve might be expected and needs to be recognised to avoid postoperative neurapraxia., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

This study aimed to describe a suitable acoustic window to facilitate access to the sciatic and femoral nerves in calves and to study the effects of their blockade with local anaesthetics. The neuroanatomical and ultrasound (US) study was performed on the cadavers of 10 calves, and the effects of 2% lidocaine with epinephrine (0.2 mL/kg) were determined in five healthy calves. The sciatic nerve in the cadavers was easily visualised as a hyperechoic band distal to the femoral greater trochanter and caudal to the femoral shaft. The femoral nerve in the cadavers was not easily identified, and was visualised as a hyperechoic oval structure situated immediately medial to the psoas major muscle and lateral to the femoral artery. The sciatic nerve was stained by methylene blue, injected under US guidance, in 9/10 cases, and the femoral nerve was stained in 6/10 cases. Sciatic nerve blockade under US guidance produced adduction of the limb with metatarsophalangeal joint flexion, while the femoral nerve blockade produced reduced weight bearing. The sciatic nerve blockade produced a reduced response to the noxious stimulus, mainly in the phalanges, proximal and distal metatarsus, tarsus and tibia and, following the femoral nerve blockade, in the medial subarea of the femur. However, femoral nerve blockade produced a more variable degree of blockade. In conclusion, US -guided anaesthetic blockade of the sciatic nerve in calves may be considered for surgery in the distal pelvic limb, although further studies are necessary to determine its clinical application., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Mechanical sensory blocking effects in the metacarpi of rams were compared following perineural injection of saline, 2% lidocaine (LIDO), 0.5% bupivacaine (BUPI), and a 1:1 (volume/volume) mixture of LIDO-BUPI. Saline was also administered in the contralateral metacarpi. Compared with the saline treatment and contralateral controls, the various treatments induced larger area under the curve (AUC) values 0-60 min post-treatment (AUC0-60). Administration of BUPI and LIDO-BUPI also induced larger AUC60-120 values (P<0.01). The AUC0-60 and AUC60-120 values with LIDO were less than those achieved with LIDO-BUPI and BUPI (P<0.001), and AUC60-120 values with LIDO-BUPI were less than those obtained with BUPI (P<0.05). Anaesthesia occurred within 5 min following the administration of all local anaesthetics and lasted longer in the case of BUPI (110.0 ± 47.3 min) than with LIDO (40.0 ± 13.2 min) (P<0.01). The duration of anaesthesia was 86.9 ± 66.0 min with the LIDO-BUPI combination. Thus this combination offered no apparent advantages over the use of BUPI alone., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

The aim of this study was to evaluate the clinical effects of a femoral nerve block via a dorsal paralumbar injection in healthy calves and calves suffering from spastic paresis. Based on bony landmarks and using ultrasound guidance, the femoral nerves of eight healthy calves were blocked bilaterally with a 4% procaine solution containing blue dye. In 11/16 nerve blocks, paralysis of the quadriceps muscle was obtained after dorsal paralumbar injection. Paralysis was total in 8/16 cases. The injection site was confirmed by post mortem dissection, and in 12/16 cases, the blue dye was found <2mm from the nerve. Clinical use of the technique was then demonstrated in two cases of atypical bovine spastic paresis. In such calves an objective diagnostic tool is required to identify those calves which are suitable for partial tibial neurectomy. The femoral nerve block used in this study has the potential to be such a method and can be used to establish the involvement of the quadriceps femoris in calves suffering from the quadriceps or mixed presentation form of spastic paresis., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

This prospective study assessed a ventral ultrasound-guided suprainguinal approach to block the femoral nerve (FN) in dogs. The anatomical features of the FN were evaluated in four canine cadavers. In another five cadavers, the FN was located by ultrasound-guidance and the accuracy of this technique was evaluated by injection of black ink and posterior evaluation of the degree of staining of the nerves. In five live dogs, the FN was blocked with 2% lidocaine. The distribution of lidocaine around the nerve and the presence of motor deficit were evaluated. The FN was easily located and accurately blocked in all cases. This new ultrasound-guided approach was reliable for blocking the FN and might be a suitable alternative to the traditional approaches described to block the FN in the dog., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

The aim of this study was to describe the sciatic-femoral nerve block (SFNB) in goats and to evaluate the peri-operative analgesia when the goats underwent stifle arthrotomy. The animals were randomly assigned to one of four treatment groups: groups 0.25, 0.5 and 0.75 received 0.25%, 0.5% and 0.75% of bupivacaine, respectively, while group C (control group) received 0.9% NaCl. In all groups, the volume administered was 0.2 mL/kg. Intra-operatively, the proportion of animals receiving rescue propofol was significantly lower in groups 0.5 and 0.75, compared to group C. Post-operatively, the visual analogue scale (VAS) and total pain score were significantly higher in group C than in the other groups. Group 0.75 had the highest percentage of animals showing motor blockade. SFNB performed with bupivacaine resulted in better intra- and post-operative analgesia than SFNB performed with saline. Compared to the other concentrations, 0.5% bupivacaine resulted in satisfactory analgesia with acceptable side effects., (Copyright © 2010 Elsevier Ltd. All rights reserved.)

The aim of this study was to investigate the use of ultrasound (US) guidance to perform sciatic and saphenous nerve blocks in dogs. Five dogs were sedated with medetomidine and butorphanol. A high-resolution US transducer was used to locate the nerves, guide placement of the needle and visualise the perineural injection of lidocaine 2%. Electrostimulation was used to confirm correct placement prior to the sciatic block. Nerve functions were evaluated over a 3 h period following administration of atipamezole. Successful identification of the nerves and the quality of the blocks were recorded. Location of the nerves, complete sensory block of the saphenous nerve, and partial to complete sensory and motor blocks of the sciatic nerve were achieved in all dogs. The resultant US guidance is potentially valuable for blocking the sciatic and saphenous nerves in dogs, although further work will be required to ensure a complete block of the sciatic nerve., (Copyright © 2009 Elsevier Ltd. All rights reserved.)

Ten canine cadavers were used to investigate the anatomy and ultrasonographic approaches to the sciatic (ScN) and femoral (FN) nerves and to assess the accuracy of an ultrasound (US) guided technique to locate and block these nerves in the dog. The nerves of four sedated dogs were sought using US, blocked with 1% lidocaine and successful location confirmed by peripheral neurostimulation. The ScN was identified by US in all cases whereas the FN was not located in all cases. This study validates the usefulness of the US-guided technique to locate and block the ScN at the midfemoral level but the acoustic window of the inguinal region was less successful for locating and blocking the FN., (Copyright © 2009 Elsevier Ltd. All rights reserved.)

Thermography is a non-contact, non-invasive technique that detects surface heat emitted as infrared radiation. Because skin temperature reflects the status of underlying tissue metabolism and blood circulation, abnormal thermal patterns can signify areas of superficial inflammation. The objective of this study was to determine if thermography could detect the injection of analgesic and neurolytic agents and surgical palmar digital neurectomy. Procedures evaluated include injection of the lumbar region, suspensory ligaments, tibial nerve, palmar digital nerves, and palmar digital neurectomy. Thermographic images were obtained before and after the procedures until a significant difference was no longer detected. Local injection of the lumbar region and the suspensory ligament produced detectable thermal patterns for two days, and tibial nerve infiltration with a neurolytic agent was significant for two days. Analgesia of the palmar nerves was significant for 24h with bupivicaine, compared to five days for ammonium chloride. Palmar digital neurectomy produced more variable thermal patterns. While sensitive enough to detect changes in heat patterns from control regions, thermography is not specific enough to discriminate between procedures and injury inducing an inflammatory response.