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Blockage of the dorsal rami of the spinal nerves (DRSN) provides analgesia to the epaxial musculature area in dogs. However, techniques to block the DRSN at the cervical level in dogs haven't yet been investigated. This study aimed to study the anatomy of the cervical area, and to describe a new ultrasound (US)-guided inter-transversospinalis plane (ITP) block technique at the 5th cervical vertebrae (C5). Fourteen adult canine's cadavers were used in this blinded, cadaveric, experimental study. One cadaver for cryo-section, one for anatomical research and twelve to do an ITP injection using 0.3 mL/kg (HV) or 0.15 mL/kg (LV) of dye/contrast solution in each lateral at C5, followed by a computed tomography and anatomical dissection. The HV and LV groups stained a median (range) of 4.67 (3-6) and 3.67 (2-5) DRSN into the ITP, respectively (P<0.017). Stained DRSN in the splenius plane were found in nine (75%) HV and five (41.66%) LV injections, respectively. Spread in the epidural space was found in two dogs using LV. One of them was injected into the ITP (4.33 %) while the other one was done accidentally outside of this plane. The paravertebral spread was found in one injection of each group. There was no dye of the ventral rami of the spinal nerves. The US-guided ITP injection is feasible in dog cadavers. The LV injected just after the medial surface of the semispinalis capitis muscle is recommended to avoid a possible extensive epidural spread., Competing Interests: Declaration of competing interest 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.)

Objective: To describe an ultrasound-guided suprazygomatic approach to the trigeminal nerve block in cat cadavers., Study Design: Prospective descriptive study., Animals: Ten feline cadaver heads., Methods: A 25:75 methylene blue-iopamidol mixture (0.1 mL cm -1 cranium length) was injected into 10 cadaver heads using an ultrasound-guided suprazygomatic approach. A computed tomography (CT) scan was performed to identify contrast presence at the orbital fissure, foramen rotundum and ovale, followed by anatomical dissection to identify staining of the pterygopalatine fossa (PPF), extraconal retrobulbar area, mandibular and maxillary nerves. Descriptive statistics were used to summarize results., Results: A total of 20 injections were performed. Of these, 1/20 misinjection occurred and excluded from further reporting. The volume of injectate was 0.9 (0.9-1.1) mL [median (range)]. Staining of the PPF, extraconal space, maxillary and mandibular nerves over more than 6 mm was achieved in 19/19 (100%), 18/19 (95%), 17/19 (89%) and 19/19 (100%) of injections, respectively. CT showed presence of contrast within 5 mm of the orbital fissure, foramen rotundum and ovale in 18/19 (95%), 19/19 (100%) and 19/19 (100%) of the injections, respectively. No intracranial migration was observed., Conclusions and Clinical Relevance: This cadaver study illustrates that the suprazygomatic ultrasound-guided trigeminal nerve injection technique can successfully stain the PPF, retrobulbar cone extraconally, mandibular and maxillary nerves. Consequently, this technique has the potential to be used in vivo in cats to desensitize areas innervated by the trigeminal nerve., (Copyright © 2024 Association of Veterinary Anaesthetists and American College of Veterinary Anesthesia and Analgesia. Published by Elsevier Ltd. All rights reserved.)

Background and Aims: The objective of this case report was to describe an ultrasound-guided, minimally invasive method for longitudinal mammary gland tissue collection from the bovine species., Materials and Methods: Biopsies were performed on 14 8-week-old calves and 113 10-week-old calves. A subset of 36 animals had repeated mammary gland biopsies through the first lactation. Mammary gland biopsies were performed using a disposable biopsy punch. The technique was also performed on multiparous cows on other independent research trials., Results: One-hundred and thirteen animals healed from the 10-week biopsies with no complications. Of the 36 animals that received repeated biopsies, one developed mastitis due to premature suture removal and one had recurring mastitis in all quarters. Thirty-three animals underwent all biopsies during gestation. Thirty of the original 36 are currently in lactation and still undergoing repeated biopsies. The method has also been successfully replicated on multiparous cows in separate studies., Discussion and Conclusion: The described technique is a safe, reliable method for cattle mammary gland biopsies beginning at eight weeks of age and can be utilized to obtain repeated tissue collection from individual animals. The technique is also straightforward to perform and utilizes simple tools while providing acceptable amounts of tissue for most applications, with low risk for infection and long-term tissue damage., (© 2024 The Author(s). Veterinary Medicine and Science published by John Wiley & Sons Ltd.)

Objective: The aim of the study was to describe laparoscopic ultrasound (LUS) to guide microwave ablation (MWA) of hepatocellular carcinoma (HCC) in a dog., Animals: A 13-year-old female spayed Husky., Study Design: Case report., Methods: The dog was referred for laparoscopic MWA of a caudate lobe HCC measuring 2.7 cm × 1.9 cm× 2.3 cm. Laparoscopic ultrasound was used to guide percutaneous placement of a MWA probe within the caudate lobe mass. LUS was used to determine the tumor margins for placement of the probe within the medial and lateral aspects as well as the center of the mass. Additionally, LUS allowed visualization of vessels within the tumor so they could be avoided during probe placement., Results: Safe ablation was accomplished, and the dog recovered uneventfully with no complications. Follow-up computed tomography (CT) 3- and 12-months postoperatively revealed complete ablation of the caudate lobe mass. However, progressive increase in size of the right medial lobe mass occurred. Right medial liver lobectomy was performed 13 months after MWA, with a histopathologic diagnosis of HCC. The dog was euthanized 777 days post MWA and 1445 days post initial left lateral lobectomy for HCC., Conclusion: Laparoscopic ultrasound was useful in guiding complete and safe MWA of an HCC in this dog. Laparoscopic ultrasound should be considered when performing laparoscopic MWA of liver lesions in dogs., (© 2024 American College of Veterinary Surgeons.)

Objective: To develop an ultrasound (US)-guided ventral approach to the brachial plexus (BP) and evaluate nerve anatomy and staining in barred owl cadavers., Study Design: Prospective, cadaveric study., Animals: Eleven adult male and female barred owl cadavers with a body mass of 0.43-0.98 kg., Methods: Eleven frozen cadavers were thawed for 48 hours, weighed and assigned a body condition score. Ten cadavers were placed in dorsal recumbency with wings abducted. US-guided visualization of the BP was achieved by placing a 13-6 MHz linear probe over the ventral aspect of the scapulohumeral joint, parallel to the sternum. A 22 gauge, 50 mm insulated needle was advanced in-plane in a caudal-to-cranial direction. In each owl, injection targeting one BP was performed with 0.4 mL kg -1 of a 1:1 0.5% ropivacaine and 1% methylene blue solution. Dissection was performed 15 minutes postinjection. Nerve staining was deemed successful if ≥ 1 cm of circumferential staining was achieved. The eleventh owl cadaver was injected with a 1:1 solution of 1% methylene blue and 74% ioversol contrast into both wings, and computed tomography (CT) was performed just before and 15 minutes after injection., Results: The BP was clearly identified ultrasonographically in cadavers weighing > 0.5 kg. An injectate volume of 0.4 mL kg -1 provided complete staining of the BP branches in all cadavers. CT scan revealed no contrast within the coelomic cavity., Conclusions and Clinical Relevance: The US-guided BP injection using a ventral approach was easily performed in barred owl cadavers weighing > 0.5 kg. The injection of 0.4 mL kg -1 of a ropivacaine-dye solution resulted in complete staining of the BP branches in all wings, suggesting that this technique could provide analgesia for structures distal to the scapulohumeral joint. Clinical studies are necessary to confirm the safety and efficacy of this technique in barred owls and other bird species., (Published by Elsevier Ltd.)

Objective: Phase 1: to determine the feasibility of desensitizing ventral branches of spinal nerves within the rectus sheath using an ultrasound-guided rectus sheath block (USRSB). Phase 2: to determine the effect of preoperative USRSB on intraoperative responses to surgical stimulation and postoperative pain., Study Design: Cadaveric study and prospective, randomized, blinded, parallel-arm clinical trial., Animals: A group of five cat cadavers and 37 shelter-owned cats undergoing ovariohysterectomy., Methods: Phase 1: anatomical dissection was performed on one uninjected cadaver. Abdominal walls were dissected in four cadavers (eight hemiabdomens) following bilateral USRSB using 1:1 new methylene blue and 0.5% bupivacaine (0.8 mL kg -1 total). Phase 2: preoperative bilateral USRSB was performed with 0.8 mL kg -1 of 0.25% bupivacaine (RSB) or equivalent volume of 0.9% saline (CONTROL). Intraoperative systolic arterial blood pressure (SAP), heart rate (HR), respiratory rate (f R ) and vaporizer setting (vap%) were recorded before skin incision, during celiotomy and abdominal wall closure. In recovery, cats were administered robenacoxib (2 mg kg -1 ; CONTROL) or 0.9% saline (0.1 mL kg -1 ; RSB) subcutaneously. Postoperative pain was evaluated for 6 hours using the Glasgow Composite Measure Pain Scale., Results: Phase 1: spinal nerves T9-L3 were identified within the rectus sheath, and stained in 0%, 40%, 63%, 75%, 100%, 88%, 50% and 13% of hemiabdomens, respectively. Phase 2: 37 cats were included (RSB, n = 17; CONTROL, n = 20). Intraoperatively, SAP, HR and f R were not significantly different between groups. Vap% was significantly lower in RSB during celiotomy (p = 0.036) and closure (p = 0.044). Postoperatively, RSB cats were 5.3 times (95% CI 1.8-8.3) more likely to require rescue analgesia than CONTROL cats., Conclusions and Clinical Relevance: During surgery, USRSB with bupivacaine offered minor benefits and provided markedly less postoperative analgesia than robenacoxib, indicating that relying on USRSB provides insufficient postoperative analgesia for ovariohysterectomy in cats., (Copyright © 2024 Association of Veterinary Anaesthetists and American College of Veterinary Anesthesia and Analgesia. Published by Elsevier Ltd. All rights reserved.)

Objective: To evaluate the feasibility of an ultrasound-guided technique targeting the medial branches of the dorsal ramus of the spinal nerves (DRSN) by injecting a dye solution at the caudal aspect of the base of lumbar mammillary processes [i.e. the retromammillary (RM) space]., Study Design: Feasibility, descriptive, anatomical study., Animals: Eleven canine cadavers., Methods: Using anatomical dissections, the relationship between the mammillary processes and the branches of the DRSN of the thoracolumbar and lumbar spine was studied in two cadavers. Subsequently, ultrasound-guided RM injections were administered in nine cadavers, randomly assigned to low volume (LV; 0.01 mL kg -1 ) of a dye solution at multiple points from L3 to L6 on one side, and high volume (HV; 0.4 mL kg -1 ) at a single L4 point on the contralateral side. Gross anatomical dissections were immediately performed after the injections. The RM injections were feasible if ultrasonographic landmarks were identifiable in at least 80% of cases, and 80% of LV injections showed medial branch staining. A one-sample binomial test was used for testing feasibility., Results: The medial branches emerged shortly after the DRSN exited the intervertebral foramen and traveled towards the caudal aspect of the base of the mammillary process, which served as the target injection point. With LV, 36 out of 36 (100%) injected medial branches were stained, meeting the criteria of feasibility (p < 0.001). The median (range) number of stained medial branches per cadaver were 4 (4-4) and 2 (1-3), with LV and HV, respectively. Although no lateral branches were stained with LV, 1 (0-2) was stained with HV. Neither ventral branch staining nor epidural spread was noted in any cadaver., Conclusions and Clinical Relevance: Ultrasound-guided RM injections are feasible and allow for selective staining of the medial branch of the DRSN in canine cadavers at the lumbar spine., (Copyright © 2024 Association of Veterinary Anaesthetists and American College of Veterinary Anesthesia and Analgesia. Published by Elsevier Ltd. All rights reserved.)

Objectives: The aim was to assess the technical success of percutaneous ultrasound-guided fine needle aspirates of gastrointestinal wall lesions and evaluate predictors of success. Secondary aims included comparing the cytological diagnosis with histopathology, evaluating the utility of concurrent locoregional lymph node cytology and assessing the procedure's complication rate., Material and Methods: Gastrointestinal wall cytology from 75 dogs and 70 cats obtained between 2018 and 2023 were reviewed and categorised as successful (resulting in a diagnostic cytology report) and accurate (resulting in the correct diagnosis when compared to histopathology). Unsuccessful fine needle aspirates, not submitted for cytology, were not recorded. Variables recorded included animal signalment, lesion and lymph node's appearance on ultrasound, size, location, number of smears submitted and experience of the ultrasonographer., Results: One hundred and fifty-two reports were analysed. Eighty-eight (58%) were successful: three normal epithelium, 21 inflammatory processes and 64 neoplasms. Variables associated with increased technical success included description of a mass, higher number of slides submitted and thickness of gastrointestinal lesion on ultrasound. Comparison with histopathology, performed for 17 lesions, showed discrepancies in eight, complete agreement in seven and partial in two. Eighty-four loco-regional lymph nodes were sampled, of which, 67 were successful (80%) and 52 brought additional clinical information (supporting GI wall cytology or diagnosing neoplasia not identified on GI wall cytology). No complication strictly attributable to gastrointestinal wall sampling was reported but when possibly related, death of the patient occurred in 2.5% of cases., Clinical Significance: Ultrasound-guided fine needle aspirate of gastrointestinal wall had moderate accuracy and was unsuccessful in 42% of cases, but technical success increased when sampling mass lesions, thicker intestinal layers and submitting more slides., (© 2024 The Author(s). Journal of Small Animal Practice published by John Wiley & Sons Ltd on behalf of British Small Animal Veterinary Association.)

Background: Cardiac catheterizations in horses are mainly performed in the right heart, as access to the left heart traditionally requires an arterial approach. Transseptal puncture (TSP) has been adapted for horses but data on follow-up and closure of the iatrogenic atrial septal defect (iASD) are lacking., Hypothesis/objectives: To perform TSP and assess postoperative complications and iASD closure over a minimum of 4 weeks., Animals: Eleven healthy adult horses., Methods: Transseptal puncture was performed under general anesthesia. Serum cardiac troponin I concentrations were measured before and after puncture. Weekly, iASD closure was monitored using transthoracic and intracardiac echocardiography. Relationship between activated clotting time and anti-factor Xa activity during postoperative enoxaparin treatment was assessed in vitro and in vivo., Results: Transseptal puncture was successfully achieved in all horses within a median duration of 22 (range, 10-104) minutes. Balloon dilatation of the puncture site for sheath advancement was needed in 4 horses. Atrial arrhythmias occurred in 9/11 horses, including atrial premature depolarizations (N = 1), atrial tachycardia (N = 5), and fibrillation (N = 3). Serum cardiac troponin I concentrations increased after TSP, but remained under the reference value in 10/11 horses. Median time to iASD closure was 14 (1-35) days. Activated clotting time correlated with anti-factor Xa activity in vitro but not in vivo., Conclusions and Clinical Importance: Transseptal puncture was successfully performed in all horses. The technique was safe and spontaneous iASD closure occurred in all horses. Clinical application of TSP will allow characterization and treatment of left-sided arrhythmias in horses., (© 2024 The Author(s). Journal of Veterinary Internal Medicine published by Wiley Periodicals LLC on behalf of American College of Veterinary Internal Medicine.)

Objective: To 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 Design: Descriptive, randomized, assessor-blinded, cadaveric study., Animals: Twelve barred owl cadavers., Methods: The 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., Results: The 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 Relevance: In 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., (Copyright © 2024 Association of Veterinary Anaesthetists and American College of Veterinary Anesthesia and Analgesia. Published by Elsevier Ltd. All rights reserved.)

This study describes the essential components and the technique of intraoperative ultrasound (IOUS), including probe selection and techniques used to produce quality images. Case examples are given to illustrate the value and the accuracy of IOUS in intracranial surgery of companion animals. IOUS has proven an invaluable addition to intracranial surgery, especially in real-time localization of the mass, identifying borders between mass and normal cerebral tissue, and identifying vascular supply to the mass., Competing Interests: Disclosure The authors have nothing to disclose., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Ultrasound-guided local anaesthesia is commonly used in veterinary orthopaedics for horses. This study aimed to assess an in vivo ultrasound technique for the medial branch of the dorsal branch of the cervical spinal nerves (MB-DBCSNs) in horses and compare the performance of clinicians with different experience levels. Ten healthy, skeletally mature horses were examined using radiographic and ultrasound (US) techniques in the cervical area (C3-C7). Four operators with varying experience conducted US examinations using a 10 MHz linear and 6 MHz curvilinear transducer over ten training sessions. The number of cervical nerves visualized was recorded. A chi-square test was used to analyse the impact of training, anatomical location, and operator experience on the identification of facet joints. Operator agreement was evaluated with Cohen's K test. The operators assessed 80 MB-DBCSNs, with radiographs and identified 70 healthy and 10 pathological facet joints. Training significantly improved visualization success, reaching 90% in later sessions. Cranial facet joints (C3-C5) were more frequently visualized (81%) than caudal ones (C5-C7) were (59%). US performance was influenced by the operator's skill, and agreement among operators ranged from slight to fair. Overall, practice improved cervical nerve visualization in vivo , particularly for cranial nerves, but the technique requires a long learning curve because of low levels of operator agreement.

Objective: To provide a video tutorial on ultrasound-guided arthrocentesis and injection of the canine hip and shoulder joints., Animals: Dogs undergoing arthrocentesis or intra-articular injection for diagnostic or therapeutic purposes., Methods: The target joint is visualized in long axis with a 70% isopropyl alcohol medium and linear array probe with a frequency range of 2 to 14 MHz and footprint of 50 mm after clipping a window and preparing the region sterilely. The needle is inserted, bevel up, in long axis with the probe angled at the appropriate trajectory to enter the joint space. The needle is advanced until the tip is visualized entering the joint. Aspiration to obtain synovial fluid can further confirm needle placement or provide diagnostic sampling prior to injection. The aspirate syringe is exchanged for that containing the therapeutic agent, and injectate can then be visualized entering and/or expanding the joint upon injection., Results: Ultrasound-guided arthrocentesis will help identify deep appendicular joints (hip and shoulder), avoid surrounding vasculature, confirm needle placement, and target joint fluid pocketing. Needle guidance into a joint can reduce iatrogenic tissue damage from inappropriate needle placement and/or by minimizing attempts., Clinical Relevance: For arthrocentesis, ultrasound guidance can maximize joint fluid volume acquisition for diagnostic purposes (cytology, culture, and fluid analysis) while also avoiding blood contamination. For joint injections, ultrasound will help ensure real-time intra-articular delivery of the injectate (regardless of attaining synovial fluid feedback) to maximize the therapeutic effect. For either purpose, iatrogenic tissue damage and procedure time are minimized.

Objective: To evaluate the impact of pecto-intercostal fascial plane block on providing intraoperative analgesia in dogs undergoing median sternotomy., Animals: 4 dogs., Clinical Presentation: The dogs were presented with a history of inappetence, lethargy and respiratory distress. Thoracic radiographs, point of care ultrasound, thoracocentesis, bronchoscopy and computed tomography was performed to characterize the disease., Results: 4 male castrated, 5.3 ± 3 years old dogs weighing 19.7 ± 13.5 kg and belonging to Dalmatian, Beagle, Siberian Husky and Rottweiler breeds were included. Three dogs were diagnosed with suppurative pleural effusions because of pulmonary abscesses and one dog with spontaneous pneumothorax due to the presence of pulmonary bullae. All dogs underwent median sternotomy under general anesthesia to explore the thorax. A pecto-intercostal fascial plane block was performed by injecting local anesthetic bupivacaine in the parasternal fascial plane between the deep pectoral and external intercostal muscles to provide antinociception by anesthetizing ventral cutaneous branches of intercostal nerves second through sixth. Analgesia from the block resulted in reduced requirement of inhalant anesthesia and minimal requirement for opioid to augment analgesia intraoperatively., Clinical Relevance: Median sternotomy is required to perform thoracic surgery in dogs with various thoracic pathologies. Pecto-intercostal fascial plane block is a locoregional technique that can blunt nociception arising from the ventral thorax and can significantly improve perioperative patient care in dogs undergoing median sternotomy by providing effective intraoperative and potentially postoperative analgesia.

Objectives: The study aimed to determine if an ultrasonic Doppler-guided technique (UDGT) leads to improved placement efficacy (time, success) of feline dorsal pedal arterial catheters vs the traditional palpation-guided technique (TPT)., Methods: A total of 26 adult, client-owned cats requiring sedation or general anesthesia for any reason, aged >12 months and weighing >3.0 kg, and with Doppler blood pressure measurements of at least 80 mmHg were enrolled. Each hindlimb was randomly assigned for dorsal pedal arterial catheterization using either the UDGT or TPT. With the UDGT, the location of the artery was identified by an audible sound using the Doppler. Successful catheter placement was confirmed by visualization of an arterial pressure waveform using a transducer and monitor system attached to the catheter. The Kaplan-Meier method and log-rank test were used to compare the two techniques., Results: The overall proportion of successful arterial catheterization was 17% (9/52): 19% (5/26) via UDGT and 15% (4/26) via TPT. Among successful arterial catheterizations (n = 9), the mean time to catheterization was 339 ± 198 s: 328 ± 237 s (n = 5) with UDGT and 353 ± 171 s (n = 4) with TPT. The log-rank test showed the two techniques were not significantly different in likelihood of successful arterial catheter placement or time to successful catheterization ( P  = 0.698). An arterial flash occurred in 62% (32/52) of the limbs, 58% (15/26) with the UDGT and 65% (17/26) with the TPT. Complications (self-limiting bruising, hematoma formation) were observed equally between UDGT (3/26 limbs) and TPT (3/26 limbs) in six cats., Conclusions and Relevance: The UDGT did not improve the efficacy of catheter placement compared with the TPT. Few complications were associated with arterial catheterization., Competing Interests: Conflict of interestThe authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Objective: To describe and evaluate the use of preoperative percutaneous ultrasound-guided anchor wire placement to aid intraoperative localization of superficial foreign bodies and abscesses in dogs., Animals: 11 dogs., Clinical Presentation: In a retrospective observational study, the medical records of dogs that underwent surgical exploration of superficial abscesses, guided by anchor wire, between 2018 and 2023 were reviewed for clinical and histopathological findings and complications. Owners or veterinarians were contacted to collect long-term follow-up information., Results: 11 dogs were included. Superficial swelling was the most common clinical presentation. Computed tomography and ultrasound revealed an abscess cavity and suspected foreign body in 9 dogs and an abscess cavity without evidence of a foreign body in 2 dogs. Anchor wires were placed in close proximity to the foreign body or inside the abscess. All documented foreign bodies were successfully located and retrieved. Two dogs suffered minor postoperative complications. No major intra- or postoperative complications were documented. One dog displayed recurrence of clinical signs, but no further surgical management was required., Clinical Relevance: Preoperative percutaneous placement of an anchor wire via ultrasound guidance was successful in aiding intraoperative localization of nonpalpable abscesses and retrieval of foreign bodies. This technique may decrease surgical time, minimize the surgical approach required, and increase the likelihood of successful localization.

Objective: To assess the perioperative analgesic effects of bilateral ultrasound (US)-guided quadratus lumborum block (QLB) using low-volume (LV) or high-volume (HV) bupivacaine, compared to a control group, in cats undergoing ovariectomy., Animals: 48 healthy female cats., Methods: Cats were sedated with IM dexmedetomidine (5 µg/kg), ketamine (1 mg/kg), and methadone (0.2 mg/kg) followed by IV propofol induction and isoflurane maintenance. Cats were randomly assigned to 3 groups of 16 patients each: QLB-LV group (0.3 mL/kg/side), QLB-HV group (0.5 mL/kg/side), and control group (no QLB). Bilateral, in-plane, US-guided QLB was performed with lateral approach at the L2 transverse process with bupivacaine 0.2%. Physiological variables were recorded intraoperatively by a masked investigator. If intraoperative nociception occurred, fentanyl (1 µg/kg) was administered IV. Rescue postoperative analgesia (buprenorphine, 0.2 mg/kg) was administered in case of a Feline Grimace Scale score ≥ 4 after a 4-hour evaluation period., Results: In the control group, heart rate (HR) was higher than the QLB-LV group during the first ovarian manipulation (P < .001) and higher than the QLB-HV group during both ovarian manipulations (P < .001 and P = .006). The need for intraoperative rescue analgesia and postoperative pain scores were significantly higher in the QLB-LV (P = .005 and P = .047) and control (P < .001 and P < .001) groups compared to the QLB-HV group. Buprenorphine was administered once in the control group. No clinical signs of bupivacaine toxicity or QLB complications were observed., Clinical Relevance: Bilateral US-guided QLB-HV may effectively provide perioperative analgesia in feline patients undergoing ovariectomy.

Background: Transvaginal ultrasound-guided aspiration (TUA) is used for post-fixation twin reduction in mares. However, there is limited information regarding factors that influence pregnancy outcome after TUA., Objectives: To evaluate the effect of day of gestation on which TUA is performed, aspiration volume, puncture of the conceptus, medication administered before and after TUA, embryo location, mare age and parity and operator experience on pregnancy and foaling rates after TUA., Study Design: Retrospective case series., Methods: Data were collected from case records of 464 TUAs performed by 14 operators in 422 mares diagnosed pregnant with dizygotic twins in two different facilities between 2010 and 2019. Pregnancy status was determined by ultrasonography at 5-7 days and 3-4 weeks after the TUA was performed. Subsequent pregnancy and foaling results were obtained by follow-up communication. The effects of mare, gestation- and TUA-related variables on pregnancy and foaling rates were analysed by the chi-square-test for homogeneity and Fisher's exact test and logistic regression., Results: TUA was performed between 21 and 82 days of gestation in unilaterally (267/359 [74.4%]) and bilaterally fixed (92/359 [25.6%]) twin pregnancies. A singleton pregnancy (218/381 [57.2%]), persistent twin pregnancy (60/381 [15.8%]), or the loss of both conceptuses (103/381 [27%]) was confirmed 5-7 days after TUA was performed. At 3-4 weeks post TUA 50.3% (163/324) of mares were diagnosed with a single viable pregnancy and 40.1% (127/317) went on to deliver a live single foal. TUA performed early in gestation (D 25-35) resulted in the birth of a live singleton foal in 49.3% (74/150) of mares., Main Limitations: Missing retrospective data despite extensive follow-up., Conclusion: This is the first large scale study to demonstrate that acceptable pregnancy and foaling rates can be achieved in mares diagnosed with twins when TUA is performed early in gestation (<40 days)., (© 2024 The Authors. Equine Veterinary Journal published by John Wiley & Sons Ltd on behalf of EVJ Ltd.)

Objective: To provide a video tutorial detailing how to perform "blind" and ultrasound-guided abdominocentesis for diagnostic and therapeutic guidance, and to provide a brief demonstration of intra-abdominal pressure measurement (IAP)., Animals: Any cat or dog with suspicion of free abdominal effusion or patients requiring measurement of IAP., Methods: Abdominocentesis should be performed when there is high suspicion for peritoneal effusion based on physical exam and/or diagnostic imaging. The 4-quadrant tap uses 20-gauge or larger needles placed blindly in ≥ 1 of the 4 quadrants of the abdomen to collect abdominal fluid. In contrast, ultrasound allows visualization of fluid in the abdomen prior to percutaneous insertion of a needle and syringe to collect fluid. Regardless of collection technique, fluid should have immediate cytologic analysis and later can be submitted for biochemical parameters, additional cellular analysis by a pathologist, and culture and sensitivity (in rare cases if indicated). Intravesicular bladder pressure measurement using a manometer-urinary catheter system approximates the IAP when there is concern for organ hypoperfusion and compartment syndrome., Results: Abdominocentesis can be performed with and without the use of ultrasound guidance. Intravesicular bladder pressure measurement is used to diagnose and trend IAP values before and after treatments are performed., Clinical Relevance: Abdominocentesis is a simple and safe technique that all small animal clinicians should be comfortable performing. Effusion sampling can guide further diagnostics and treatments. Measurement of IAP is simple and requires no specialized equipment.

Objective: To compare the success rate and extent of sciatic nerve staining with a bupivacaine-dye solution using two injection techniques: 'blind' or ultrasound-guided approach., Study Design: Prospective, experimental, randomized, cadaveric study., Animals: Adult female Wistar rat cadavers [n = 24, mass 352 g (323-374)]., Methods: Each sciatic nerve was randomly allocated to one of two groups: 'blind' (group B) or ultrasound-guided approach (group US) to injection. Following injection of bupivacaine-dye solution (0.1 mL), gross anatomical dissection was performed to visualize nerve staining, categorizing it as either positive or negative. The length of nerve staining was then measured and visual inspection conducted to identify potential nerve damage. Fisher's exact test was used to compare positive or negative nerve staining, and the Wilcoxon signed rank test used to compare the length of nerve staining between groups., Results: In group B, the bupivacaine-dye solution stained 16/24 sciatic nerves (67% success). In group US, staining was successfully observed in all 24 nerves (100% success, p < 0.004). The length of nerve staining [median (interquartile range)] was 2 (2-3) mm in group B and 5 (4-6) mm in group US (p < 0.001). One sciatic nerve in group B had injectate distributed over 16 mm, suggestive of an intraneural injection. No signs of laceration or nerve damage were visible under 6× magnification in either group., Conclusions and Clinical Relevance: The ultrasound-guided approach for sciatic nerve injection demonstrated a higher success rate with superior injectate distribution when compared with the 'blind' approach. Ultrasound guidance is recommended over a 'blind' approach for sciatic nerve block in rats when possible., (Copyright © 2024 Association of Veterinary Anaesthetists and American College of Veterinary Anesthesia and Analgesia. Published by Elsevier Ltd. All rights reserved.)

Objective: To compare motor effects and analgesic efficacy following an ultrasound-guided lateral approach to lumbar plexus blockade at L7 and sciatic nerve blockade (LPSNB) against epidural injection in dogs undergoing tibial plateau leveling osteotomy (TPLO)., Study Design: Prospective, randomized, blinded clinical trial., Animals: A total of 27 healthy adult dogs undergoing unilateral TPLO surgery., Methods: Dogs were allocated to either LPSNB (bupivacaine 2 mg kg -1 , 0.75%) or epidural (morphine PF 0.1 mg kg -1 and bupivacaine 0.5 mg kg -1 , 0.75%). Other aspects of clinical management were identical, including anesthetic drug protocol, area of presurgical clipping and bladder care. Time to perform the block, response to surgical stimuli, pain scores, rescue analgesia, time to stand and walk, motor score and time to first urination were recorded. One evaluator, unaware of treatment status, performed all evaluations. Student's t-test or Mann-Whitney U test was used to compare continuous variables between groups, and Fisher's exact test for categorical variables., Results: Median (range) times to stand and walk were shorter for LPSNB [60 (40-120) minutes and 90 (60-150) minutes, respectively, p = 0.003] than for epidural [150 (120-240) minutes and 180 (120-360) minutes, respectively, p = 0.006]. Four dogs required rescue intraoperatively (three in epidural group, one in LPSNB group, p = 0.438). Pain scores over the 24 hour evaluation period were similar, and not significantly different, for each group. Time to spontaneous urination [LPSNB, 330 (240-360) minutes; epidural, 300 (120-1440) minutes, p = 1.0] did not differ between groups., Conclusions and Clinical Relevance: An ultrasound-guided lateral paravertebral approach to the lumbar plexus within the psoas compartment at L7, combined with sciatic nerve blockade, allows faster return to normal motor function, with similar pain control and impact on urination when compared with epidural in dogs after TPLO surgery., (Copyright © 2023 Association of Veterinary Anaesthetists and American College of Veterinary Anesthesia and Analgesia. Published by Elsevier Ltd. All rights reserved.)

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.)

Objective: To 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 Design: Randomized, experimental, assessor-blinded cadaveric study., Animals: A total of 40 adult female Wistar rat cadavers., Methods: After 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., Results: The 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 Relevance: This 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., (Copyright © 2023 Association of Veterinary Anaesthetists and American College of Veterinary Anesthesia and Analgesia. Published by Elsevier Ltd. All rights reserved.)

Background: Regional anesthesia is the favored choice in ruminant animals compared to general anesthesia, primarily due to its high safety margin and reduced demand for cost-intensive equipment in addition to its field applicability. Ultrasound-guided nerve block has gained significant attention in the field of veterinary medicine. This study utilized twenty-seven sheep of the native Rahmani breed to both demonstrate and evaluate the effectiveness of the ultrasound guided inferior alveolar nerve block technique., Methods: The research comprised three phases: Phase 1 involved an anatomical examination of mandibles and sheep heads to locate the mandibular foramen and delineate the mandibular nerve course. Phase 2 included ultrasound-guided injection of methylene blue dye at specific sites along the mandibular nerve in cadaveric sheep heads. In Phase 3, clinical implementation of ultrasound-guided inferior alveolar nerve blocks was conducted in 27 live sheep, assessing efficacy, onset, and duration., Results: Vertical extraoral ultrasound-guided nerve block was achieved successfully in 25 sheep (98%). A preliminary cadaveric study showed good distribution of the injectate at the mandibular nerve site. The mean onset time was 138 ± 18 s, and the mean duration time was 54 ± 4.1 min. Prominent analgesia of the ipsilateral mandible, medial surface of the cheek, and lateral border of the tongue was observed., Conclusions: Ultrasound-guided mandibular nerve block holds promise as a technique for providing effective and safe anesthesia in sheep undergoing mandibular procedures., (© 2024. The Author(s).)

The increasing use of ultrasound in veterinary private practice and demand for skilled operators upon graduation has placed an increased burden on the ever-dwindling number of academic radiologists. Simulation-based medical education can help prepare for and consequently reduce this burden, allowing for the acquisition of clinical skills through deliberate practice in a safe, controlled, and low-stakes environment. Ultrasound-guided fine needle placement is the foundation for more advanced interventions such as ultrasound-guided fine needle aspirates and centeses. A reusable novel ultrasound skill simulator consisting of metal targets wired to a circuit and suspended in ballistics gel was created to teach ultrasound-guided fine needle placement. Forty-seven second-year veterinary students watched an instructional video and performed two ultrasound-guided fine needle placement skill tests on the simulator with a period of practice between. Significant improvement in time to task completion ( p = .0021) was noted after the period of practice. The majority of student feedback was positive with 89% (42/47) indicating they would use the simulator again to practice and that it should be incorporated into the curriculum, 74% (35/47) indicating their basic skills, knowledge, and confidence using ultrasound improved using the simulator, and 55% (26/47) indicating they could now teach this skill to a peer. The authors suggest further development of this model for ease of manufacture and increased variation in difficulty, and veterinary curriculum incorporation for basic ultrasound-guided fine needle placement training.

A 3-year-old spayed female Rottweiler dog was brought to a veterinary clinic because of weakness, lethargy, and hair coat changes. Hematology and clinical chemistry assessments revealed anemia, hypoalbuminemia, hyperglobulinemia, and hypothyroid. After persistent pyuria, an ultrasound-guided cystocentesis was completed, which revealed a large abdominal mass. A presumptive diagnosis of canine lymphoma with renal spread was made. Due to a poor prognosis, the dog was euthanized., (Copyright and/or publishing rights held by the Canadian Veterinary Medical Association.)

Objective: This study compared the quality of retrobulbar anesthesia using a blind inferior-temporal palpebral approach (ITP) with an ultrasound-guided supratemporal (ST) technique in dogs undergoing unilateral enucleation., Animal Studied: Twenty-one client-owned dogs were undergoing enucleation., Procedures: Dogs were randomly assigned to receive ITP (n = 10) or ST (n = 11) with 0.5% ropivacaine at 0.1 mL/cm of neurocranial length. The anesthetist was blinded to the technique. Intraoperative data included cardiopulmonary variables, inhalant anesthetics requirement, and requirement for rescue analgesia (intravenous fentanyl 2.5 mcg/kg). Postoperative data included pain scores, sedation scores, and need for intravenous hydromorphone (0.05 mg/kg). Treatments were compared using Wilcoxon's rank sum test or Fisher's exact test as appropriate. Comparison of variables over time were tested using a mixed effect linear model on rank. Significance was set at p = 0.05., Results: Intraoperative cardiopulmonary variables and inhalant requirements were not different between groups. Dogs receiving ITP required median (interquartile range, IQR) 1.25 (0, 2.5) mcg/kg intraoperative fentanyl while those receiving ST required none (p < 0.01). Intraoperative fentanyl was required in 5/10 and 0/11 of dogs in the ITP and ST groups, respectively (p = 0.01). Postoperative analgesia requirements were not significantly different between groups; 2/10 and 1/10 dogs in the ITP and ST groups, respectively. Sedation score negatively affected pain score (p < 0.01)., Conclusions: The ultrasound-guided ST technique was more effective at decreasing intraoperative opioid requirements than the blind ITP approach in dogs undergoing unilateral enucleation., (© 2023 The Authors. Veterinary Ophthalmology published by Wiley Periodicals LLC on behalf of American College of Veterinary Ophthalmologists.)

Objective: To develop an ultrasound-guided caudal quadratus lumborum block (C-QLB) technique in canine cadavers and to compare sensory and motor blockade resulting from the combination of ultrasound-guided greater ischiatic notch (GIN) plane and C-QLB approaches (GIN-CQLB group) versus a lumbosacral plexus (LSP group) approach [combination of lateral pre-iliac (LPI) and parasacral (PS) techniques] in dogs., Study Design: Descriptive anatomical study and prospective randomized, blinded, experimental crossover trial., Animals: A total of six canine cadavers and six adult Beagle dogs., Methods: Phase I: following ultrasound-guided C-QLB injections of 0.3 mL kg -1 of dye, using the interfascial plane located lateral to the quadratus lumborum muscle at the level of the sixth lumbar vertebra (L6) as injection point, the spread of injectate and nerve staining was evaluated using gross anatomical dissection., Phase Ii: sensory and motor blockade achieved with the GIN-CQLB or LSP blocks in Beagle dogs were evaluated and compared. The assigned technique was performed with 2% lidocaine: 0.2 mL kg -1 for the GIN and PS approaches and 0.3 mL kg -1 for the C-QLB and LPI approaches., Results: Dissection revealed distribution of dye around the lumbar hypaxial musculature, extending into the paravertebral spaces, with staining of 3 (2-4) [median (interquartile range)] spinal nerves, spanning L3 to L6. The median motor blockade in the GIN-CQLB and LSP groups was 7 (7-8) versus 16 (10-16) (p = 0.026), whereas the median sensory blockade was 5 (4-5) versus 3 (3-3) (p = 0.025), respectively., Conclusion and Clinical Significance: The GIN-CQLB approach desensitized the thigh dermatomes effectively. Compared with the LSP approaches, GIN-CQLB exhibits a motor-protective effect by preserving tonic muscle function., (Copyright © 2023 Association of Veterinary Anaesthetists and American College of Veterinary Anesthesia and Analgesia. Published by Elsevier Ltd. All rights reserved.)

Objective: To investigate and describe an extraoral approach to perform a maxillary nerve block in guinea pigs., Study Design: Prospective, randomized, blinded, descriptive, cadaveric study., Animals: A total of 14 adult guinea pig cadavers., Methods: Two cadavers were used for anatomic dissection and determination of maxillary nerve block approach. A maxillary nerve block via infraorbital approach was then performed in 12 cadavers. A low volume (0.1 mL) or high volume (0.2 mL) of diluted methylene blue injectate was randomly assigned to the right or left side, with the other volume used for the contralateral side. The maxillary nerve was dissected after each injection by an investigator blinded to injectate volume. The region of dye distribution was identified, and the degree of staining assigned an accuracy score (0-2). Nerve coverage was considered adequate if ≥6 mm of circumferential staining was present., Results: Accuracy evaluation indicated successful dye deposition in 10/12 [2 (0-2), median (range)] injections in the low volume group and 8/12 [2 (1-2)] injections in the high volume group. The majority (79.2%) of injections resulted in adequate nerve staining. There were no statistically significant differences between injectate volumes for accuracy (p = 0.64) or adequacy (p > 0.99) of staining., Conclusions: The infraorbital approach is a simple and practical method for maxillary nerve blockade in guinea pigs. An injectate volume of 0.1 mL results in adequate maxillary nerve coverage; however, additional studies are needed to assess the efficacy in clinical use., (Copyright © 2023 Association of Veterinary Anaesthetists and American College of Veterinary Anesthesia and Analgesia. Published by Elsevier Ltd. All rights reserved.)

Objective: Novel locoregional techniques use dye studies to confirm successful nerve targeting. The goal was to objectively quantify and compare nerve staining characteristics of dye mixtures commonly reported in the literature using image analysis software., Study Design: Prospective, randomized cadaveric study., Methods: Thirty-six brachial plexus nerves from unpreserved pig cadavers were randomized into three groups of 12: FD (1:10 mixture of blue food dye and bupivacaine 0.5%), MB (methylene blue 1%) and TM (0.1:10 mixture of blue tissue marker and lidocaine 2%). Nerves were immersed in dye for 1, 15, 30 or 60 minutes (n = 3 each). Images of nerves before immersion (baseline) and at each time point with epineurium intact (superficial staining) and after longitudinal bisection (deep staining) were processed using image analysis software. Color saturation values were divided into quartiles (dark, medium-dark, medium-light or light). Percentage of stained nerve area in each quartile was calculated and compared using two-way anova., Results: Superficially, at minute 1, dark saturation covered 40% of nerve area in FD versus 19% in MB (p = 0.04) and 0% in TM (p < 0.0001). In bisected nerves, dark and medium-dark saturations occurred only in FD; medium-light saturation comprised anywhere from 4% to 22.5% over time in FD versus <1% at any time in MB (p = 1.000; p = 0.343; p = 0.383; p = 0.262). Deep staining was not found in TM at any point., Conclusion and Clinical Relevance: Food dye rapidly stains superficial and deep nerve layers. Based on these characteristics, investigators can choose the appropriate dye for their study., (Copyright © 2023 Association of Veterinary Anaesthetists and American College of Veterinary Anesthesia and Analgesia. Published by Elsevier Ltd. All rights reserved.)

A 4-month-old female-entire Vizsla dog was referred for progressive seizure activity, vomiting, lethargy, inappetence, and neck pain. CT revealed focal inflammation, a calvarial osseous defect, a possible foreign body within the brain, and associated vasogenic edema. A cerebrospinal fluid tap revealed marked septic neutrophilic pleocytosis. MRI findings supported diagnosis of a 1.7 cm foreign body within the brain. A right rostrotentorial craniectomy was performed, and intraparenchymal grass seed was removed in its entirety via intraoperative ultrasound guidance. The patient was discharged 2 days postoperatively, and long-term follow-up revealed no abnormal neurological signs., (© 2023 American College of Veterinary Radiology.)

Objective: To develop and assess the feasibility, as a diagnostic block, of an ultrasound-guided lateral pericapsular hip desensitization (L-PHD) technique in dogs., Study Design: Prospective, randomized, anatomical and feasibility study., Animals: A total of 11 canine cadavers and eight adult dogs scheduled for acetabular surgical denervation., Methods: After studying the ultrasound anatomy of the lateral aspect of the gluteal region and determining an acoustic window to perform an ultrasound-guided L-PHD in three canine cadavers, the right and left hemipelves of eight canine cadavers were injected in the interfascial plane located lateral (L L -PHD group) or medial (L M -PHD group) to the deep gluteal muscle, with 0.05 mL kg -1 of dye per hip on each cadaver. The staining of the pericapsular nerves was assessed by anatomical dissection. Then, the L M -PHD was performed using 2% lidocaine as a diagnostic block in dogs scheduled for acetabular surgical denervation. Positive predictive value (PPV) was calculated for those animals who had favorable outcomes after acetabular surgical denervation., Results: The ultrasound-guided L L -PHD and L M -PHD could be performed by inserting the needle lateral and medial to the deep gluteal muscle. Ultrasound-guided L L -PHD stained the cranial gluteal nerve and its muscular branches in all injections and partially stained the lumbosacral trunk in two out of eight cadavers. The L M -PHD selectively stained the articular branches of the cranial gluteal nerve in all but one cadaver. The PPV for L M -PHD successful test prediction was 85.7% (95% confidence interval: 48.6% to 98.6%)., Conclusions: and clinical significance Ultrasound-guided L M -PHD using 0.05 mL kg -1 of dye selectively stained the articular branches of the cranial gluteal nerve in canine cadavers. The L M -PHD technique is feasible and could be used as a diagnostic block before acetabular surgical denervation in dogs., (Copyright © 2023 Association of Veterinary Anaesthetists and American College of Veterinary Anesthesia and Analgesia. Published by Elsevier Ltd. All rights reserved.)

Shoulder joint disease is a common cause of forelimb lameness in dogs. To diagnose this condition, shoulder magnetic resonance arthrography (MRA) is performed, which involves the injection of contrast agents into the shoulder joint space under ultrasound (US)-guidance. The objective of this study was to compare the craniolateral and caudolateral approaches for shoulder MRA using US-guided injection techniques, and investigate their clinical feasibility in dogs. Forty shoulder joints from 10 adult beagles were studied in two repetitions. The craniolateral (n = 20) and caudolateral (n = 20) injection techniques were applied randomly under US-guidance. The shoulder MRA was conducted immediately after the contrast agents was injected. The procedure time (scan and injection time), number of attempts, joint distension and degree of extraarticular extravasation were recorded and compared between the two groups. The results showed that the caudolateral approach had significantly more contrast agents extravasation compared to the craniolateral approach (p < 0.05). However, there were no significant differences between the two groups in terms of procedure time (scan time p = 0.80, injection time p = 0.74), number of attempts (p = 0.70) and joint distension (p = 0.23). The craniolateral approach of US-guided contrast injection techniques for shoulder MRA minimizes damage to the juxta-articular structures and reduces extraarticular extravasation, resulting in good-quality images. This study demonstrates the feasibility and advantages of the craniolateral approach under US-guidance for shoulder MRA in dogs., (© 2023 Wiley-VCH GmbH. Published by John Wiley & Sons Ltd.)

Background: The study aimed to assess the clinical utility of a multiparametric approach to measure the impact of bilateral ultrasound-guided rectus sheath blocks (RSB) on heart rate, serum cortisol concentrations, and pain in calves undergoing herniorraphy. Fourteen calves were randomly assigned to receive either the RSB (RSB group, n = 7, injected with 0.3 mL/kg of bupivacaine 0.25% and 0.15 µg/kg of dexmedetomidine per side) or a sham injection (CG group, n = 7, injected with an equivalent volume of sterile saline solution). Monitoring included (i) continuous Holter recording from 120 min pre-surgery to 120 min post-surgery; (ii) serum cortisol concentration (SC) at -150 min pre-surgery (baseline), induction time, skin incision, end of surgical procedure (EP-t), and then 30 min, 45 min, 60 min, 120 min, 360 min after recovery; (iii) UNESP-Botucatu pain evaluation at -150 min pre-surgery and 30 min, 45 min, 60 min, 120 min, 240 min, 360 min after recovery., Results: A significant difference in the heart rate was observed within the RSB group, in the time frame between 120 min to induction compared to the time frame between induction to EP-t period. The SC concentration was significantly higher in the CG at the skin incision. Calves in the RSB group recorded significantly lower pain scores at 45 min, 60 min, 120 and 240 min after recovery., Conclusions: The study demonstrated that monitoring heart rate and serum cortisol concentrations effectively quantified the effects of RSB during surgery. At the same time, the UNESP-Botucatu pain scale identified effects post-surgery when the calves regained consciousness. Overall, ultrasound-guided RSB appeared to enhance the well-being of calves undergoing herniorrhaphy., (© 2023. BioMed Central Ltd., part of Springer Nature.)

Hydatid disease caused by Echinococcus ortleppi is a major cause of morbidity and mortality for critically endangered captive langurs in northern Vietnam. The most common sites for hydatid cyst development are the liver and the lungs. Chemotherapy trials with albendazole alone or in combination with praziquantel in these langurs had varying results and in most cases were ineffective. Ultrasound-guided percutaneous aspiration of cystic fluid followed by instillation and re-aspiration of a scolicidal agent (PAIR technique), has gained importance in the treatment of active hepatic cysts in humans and in many cases is preferred over surgical and endoscopic approaches. The PAIR technique was used in two red-shanked douc langurs ( Pygathrix nemaeus ) for the treatment of unilocular active hepatic cysts. The technique was found to be fairly easy to perform, safe, and effective and should be a useful treatment tool for hepatic hydatidosis in langurs and other nonhuman primate species.

This prospective clinical study sought to determine the accuracy of cytopathologic examination and needle-core biopsy (NCB) against diagnoses obtained by excisional histopathology (EH) for canine splenic masses. Twenty-five masses were evaluated ex vivo by ultrasound-guided fine-needle aspiration (FNA) and NCB tissue sampling. Each spleen was placed in a container and artificial skin placed over its surface. Ultrasound-guided FNA using a 22-gauge needle and 2 NCB samples [14-gauge (NCB-14), 16-gauge (NCB-16)] were obtained and submitted for analysis. Results were compared to results obtained by splenic excisional histopathology (EH). There was no difference noted between FNA, NCB-14, or NCB-16 analyses. In addition, there was no difference in accuracy between FNA and NCB-14 or between FNA and NCB-14 versus NCB-16. Reported accuracy of FNA was 0.72, NCB-14 was 0.72, and NCB-16 was 0.64, respectively. Both FNA and NCB-14 displayed a sensitivity of 71% and NCB-16 a sensitivity of 53%. Both FNA and NCB-14 displayed a specificity of 75% and NCB-16 a specificity of 88%. The results demonstrated that NCB had no advantage clinically over FNA at diagnosing splenic pathology. This study further demonstrates that preoperative diagnostic evaluation of the spleen is not highly accurate and cannot be recommended prior to splenectomy., (Copyright and/or publishing rights held by the Canadian Veterinary Medical Association.)

Objective: To describe the gross and ultrasound anatomy of the parasacral region and an ultrasound-guided greater ischiatic notch (GIN) plane approach aimed at staining the lumbosacral trunk (LST) in canine cadavers. To evaluate if the ultrasound-guided GIN plane approach is non-inferior to the previously described ultrasound-guided parasacral approach at staining the LST., Study Design: Prospective, randomized, non-inferiority experimental anatomic study., Animals: A total of 17 (23.9 ± 5.2 kg) mesocephalic canine cadavers., Methods: Anatomic and echographic landmarks, and the feasibility of performing a GIN plane technique were evaluated using two canine cadavers. The remaining 15 cadavers had each hemipelvis randomly assigned to be administered either parasacral or GIN plane injection of 0.15 mL kg -1 dye solution. The parasacral region was dissected after injections to assess the staining of LST, cranial gluteal nerve, pararectal fossa and pelvic cavity. The stained LST were removed and processed for histological evaluation of intraneural injections. A one-sided z-test for non-inferiority (non-inferiority margin -14%) was used to statistically evaluate the success of the GIN plane versus the parasacral approach. Data were considered statistically significant when p < 0.05., Results: The GIN plane and parasacral approach stained the LST in 100% and 93.3% of the injections, respectively. The success rate difference between treatments was 6.7% [95% confidence interval, -0.6 to 19.0%; p < 0.001 for non-inferiority]. The GIN plane and parasacral injections stained the LST for 32.7 ± 16.8 mm and 43.1 ± 24.3 mm, respectively (p = 0.18). No evidence of intraneural injection was found., Conclusions and Clinical Relevance: The ultrasound-guided GIN plane technique resulted in nerve staining that was non-inferior to the parasacral technique and may be considered an alternative to the parasacral approach to block the LST in dogs., (Copyright © 2023 Association of Veterinary Anaesthetists and American College of Veterinary Anesthesia and Analgesia. Published by Elsevier Ltd. All rights reserved.)

Modifications of splenic parenchyma are common ultrasonographic findings in dogs. Splenic fine needle aspiration (FNA) is a rapid, safe procedure, routinely performed in veterinary institutions. However, 22-gauge (G) needle usually reported is selected according to general practice and the most appropriate needle size to be used remains unclear. The aim of this prospective, single-center, methods comparison study was to assess the effect of needle size on cytologic specimens' evaluation and animal welfare during the procedure. Dogs underwent ultrasound-guided splenic FNA using 23, 25, and 27G needles. Needles were compared based on initial and then detailed cytologic evaluation. The initial evaluation assessed overall cellularity, cell preservation, hemodilution, and detailed cytologic evaluation referred to exhaustive splenic components. Welfare evaluation was performed based on a scoring system. A total of 54 dogs were included in this study with 54 of 54 welfare evaluations and 35 of 54 cytologic evaluations by one or two European College of Veterinary Clinical Pathology-certified cytologists. The final cytologic diagnosis was unchanged regardless of the needle size. For the initial evaluation, 23G needles provided significantly higher cellularity than the 27G needles. For detailed cytologic evaluation, only the richness in mesothelial cells and stroma was affected by needle size. Pain induced by the procedures was considered low using 23, 25, and 27G needles with the 27G needle producing the least adverse reactions. Findings from the current study supported using needle gauges smaller than the previously published standard 22G needle for spleen ultrasound-guided fine needle nonaspiration in dogs. Due to higher cellularity and lower pain scores, authors recommend the use of 23G needles with a nonaspiration technique., (© 2023 American College of Veterinary Radiology.)

Delivery of mesenchymal stem cells (MSC) via intravascular techniques to treat diffuse and/or inaccessible soft tissue injuries has grown in popularity. The purpose of the current prospective, analytical pilot study was to utilize CT to validate this novel technique and provide additional evidence to support its use for injectate delivery to specific soft tissue structures. Of particular interest was the proximal suspensory ligament, which presents a challenging injection target. Six adult horses without lameness underwent CT of the distal hindlimbs. Scans were obtained prior to ultrasound-guided catheterization of the cranial tibial artery, in addition to early and delayed scans acquired following intra-arterial contrast administration. Region of interest analysis of the superficial and deep digital flexor tendons and suspensory ligament was used to assess contrast enhancement within these structures. Linear mixed models were used to determine statistical significance. Significant (P < 0.05) mean contrast enhancement was seen in all postinjection time points in all soft tissue structures of interest. This indicates that ultrasound-guided injection of the cranial tibial artery results in perfusion of injectate throughout the distal hind limb, including the major soft tissue structures of the metatarsus. This provides further support for this technique as a method of MSC delivery to multifocal or inaccessible injury of these structures, including the proximal suspensory ligament., (© 2023 The Authors. Veterinary Radiology & Ultrasound published by Wiley Periodicals LLC on behalf of American College of Veterinary Radiology.)

Background: Percutaneous renal cyst sclerotherapy (PRCS) as a treatment for renal cysts is usually performed with a high concentration of ethanol (≥ 90%). This study reviewed cases in which a lower concentration of ethanol (83%) was used for the procedure in dogs., Methods: Records of cases of renal cysts treated by sclerotherapy using 83% ethanol in dogs were reviewed. Outcomes of the treatment were evaluated by comparing volumes of renal cysts before the procedure and the volumes after treatment, using ultrasound images with the volume reduction rates classified as follows: < 50% of initial volume (failed); ≥ 50% but < 80% of initial volume (partial success); ≥ 80% but < 95% of initial volume (great success); ≥ 95% of initial volume (complete success)., Results: Out of nine dog kidneys, renal cysts sclerotherapy with 83% ethanol achieved partial success in one kidney, great success in four, and complete success in the other four. No side effect was observed. The mean of the volume-reduction rates was 90.00 ± 11.00 while the minimum and maximum reduction rates were 65% and 100%, respectively., Conclusions: The lower ethanol concentration (83%) is good for disinfecting kidneys in PRCS., Competing Interests: The authors declare no conflicts of interest., (© 2023 The Korean Society of Veterinary Science.)

Techniques for local anesthesia of the tibial (TN) and superficial and deep fibular nerves (FNs) in horses are well established. Ultrasound-guided perineural blocks can identify the nerve location, reduce the anesthetic volume needed and avoid needle misplacement. The aim of this research was to compare the success of blind perineural injection technique (BLIND) to ultrasound-guided technique (USG). Fifteen equine cadaver hindlimbs were divided into two groups. Perineural injection of the TN and FNs was performed using a mixed solution of radiopaque contrast, saline and food dye. BLIND (n = 8) used 15 mL for the TN and 10 mL for each fibular nerve. USG (n = 7) used 3 mL for the TN and 1.5 mL for each fibular nerve. The limbs were radiographed immediately after injections and sectioned transversally to evaluate the diffusion and presence of the injectate adjacent to the TN and FNs. The presence of dye immediately adjacent to the nerves was considered a successful perineural injection. No statistically significant difference was observed between groups for success. Distal diffusion of injectate following perineural injection of the TN was significantly less for USG compared to BLIND. Proximal, distal and medial diffusion of injectate following perineural injection of FNs was significantly less for USG compared to BLIND. Low-volume USG results in less diffusion but similar success compared to BLIND leaving it up to veterinarian preference when selecting a technique., (Copyright © 2023. Published by Elsevier Inc.)

Background: Arterial access in small-breed dogs is challenging, but arterial visualisation may facilitate the procedure, as evidenced in human medicine. This prospective, randomised study investigated the result of using transillumination to guide coccygeal artery cannulation in small-breed dogs., Methods: Coccygeal artery cannulation was attempted in dogs anaesthetised with butorphanol, midazolam, propofol and sevoflurane. In 70 dogs (standard technique group [S TECHNIQUE group]), arterial cannulation was performed using pulse palpation. In 71 dogs (transilluminating-standard technique group [TS TECHNIQUE group]), a transilluminating device was utilised. The device was placed on the dorsal tail, and the cannula was advanced towards the dark line visible against the bright background. If the artery was not well visualised due to pigmentation, pulse palpation was used. The success rate of arterial cannulation was compared between the groups using the chi-squared test., Results: Arterial cannulation was significantly more successful (p < 0.001) in the TS TECHNIQUE group (63/71 [88.7%]) than in the S TECHNIQUE group (43/70 [61.4%])., Limitations: The number of punctures attempted and the time to cannulation were not assessed, and the procedure was only performed by veterinarians experienced in arterial cannulation., Conclusions: The transillumination allows for a more accurate approach to the coccygeal artery, improving the success of arterial cannulation when combined with pulse palpation., (© 2023 British Veterinary Association.)

Currently, a histological diagnosis of highly vascularized canine (c) thyroid carcinoma (TC) is primarily obtained following excisional biopsy (EB) through thyroidectomy. Non-EBs are contraindicated in unresectable invasive cTCs due to their highly vascularized nature, which subsequently, lack histological diagnosis. We hypothesised ultrasound-guided core needle biopsy (UGCNB) to be a safe biopsy technique to obtain an accurate histological diagnosis in unresectable TCs. Nine client-owned dogs with suspected naturally occurring TC, presented for surgical excision, were included. First, a UGCNB was taken from the cervical tumour, followed by EB. Haemorrhage following UGCNB was evaluated preoperatively and once the tumour was surgically exposed by visual inspection and ultrasonography. Histological analysis, including cell organisation, tumour capsular and vascular invasion, and immunohistochemistry were performed and compared between both biopsy specimens (i.e., UGCNB and EB) of the same dog. Pre- and peroperative visual inspection revealed minor, localised haemorrhage, subsequent to the UGCNB, in 7/9 dogs. Histology of the EBs confirmed TC in 8/9 dogs and was inconclusive in 1/9 dogs. Histology of the UGCNBs revealed neoplastic thyroid tissue in 7/9 UGCNBs and was inconclusive in 1/9 UGCNBs. The remaining UGCNB contained no mass related tissue and was, therefore, excluded. Histological parameters (i.e., cell organisation, tumour capsular and vascular invasion) were not concordant between 6/8 included UGCNBs and their respective EB. Immunolabelling for thyroglobulin and calcitonin was concordant between all eight included UGCNBs and their respective EB. The remaining evaluated immunohistochemical markers (i.e., cyclooxygenase-2 [COX-2], P-glycoprotein and vascular endothelial growth factor [VEGF]) were concordant between the included UGCNBs and the EBs in 6/8 dogs. To conclude, UGCNBs can be safely obtained in suspected cTCs and enable a reliable diagnosis of the thyroid origin, thyroid cell origin and potential therapeutic markers such as COX-2, P-glycoprotein and VEGF. Subsequently, UGCNB enables clinicians to establish an individually tailored treatment plan in dogs with unresectable TC., (© 2023 John Wiley & Sons Ltd.)

Objective: To evaluate a regional anesthetic technique for blocking the abdominal midline in horses., Study Design: Anatomical description and prospective, crossover, placebo-controlled, blinded study., Animals: Adult horses; two cadavers, six healthy animals., Methods: In stage 1, 0.5% methylene blue with 0.25% bupivacaine (0.5 mL kg -1 ) was injected using ultrasonography into the internal rectus abdominis sheath (RAS) of two cadavers with a one-point or two-point technique. The dye spread was described after the dissection of the abdomens. In stage 2, each horse was injected with 1 mL kg -1 of 0.9% NaCl (treatment PT) or 0.2% bupivacaine (treatment BT) using a two-point technique. The abdominal midline mechanical nociceptive threshold (MNT) was measured with a 1 mm blunted probe tip and results analyzed with mixed-effect anova. Signs of pelvic limb weakness were recorded., Results: The cadaver dissections showed staining of the ventral branches from the eleventh thoracic (T11) to the second lumbar (L2) nerve with the one-point technique and T9-L2 with the two-point technique. Baseline MNTs were, mean ± standard deviation, 12.6 ± 1.6 N and 12.4 ± 2.4 N in treatments PT and BT, respectively. MNT increased to 18.9 ± 5.8 N (p = 0.010) at 30 minutes, and MNT was between 9.4 ± 2.0 and 15.3 ± 3.4 N from 1 to 8 hours (p > 0.521) in treatment PT. MNTs in treatment BT were 21.1 ± 5.9 to 25.0 ± 0.1 N from 30 minutes to 8 hours (p < 0.001). MNTs after the RAS injections were higher in treatment BT than PT (p = 0.007). No pelvic limb weakness was observed., Conclusions and Clinical Relevance: Antinociception of at least 8 hours without pelvic limb weakness was observed in the abdominal midline in standing horses after the RAS block. Further investigations are necessary to evaluate suitability for ventral celiotomies., (Copyright © 2023 Association of Veterinary Anaesthetists and American College of Veterinary Anesthesia and Analgesia. Published by Elsevier Ltd. All rights reserved.)