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This study aimed to describe an ultrasound-guided technique for implanting catheters for local anesthetic administration into the quadratus lumborum (QL) inter-fascial plane in canine cadavers and assessing the spread along the vertebral bodies (VBs) by computed tomography (CT). Phase 1: eight canine cadavers received one catheter per hemiabdomen, followed by injection of contrast media solution [low volume (LV) 0.3 mL kg−1 or high volume (HV) 0.6 mL kg−1]. Phase 2: postoperative pain of five dogs was managed by injecting 0.3 mL kg−1 of ropivacaine 0.5% through QL catheters every eight hours, up to 72 h after abdominal surgery. Pain was assessed using the Short Form of the Glasgow Composite Measure Pain Scale, and methadone 0.2 mg kg−1 was administered intravenously when the pain score was ≥6. The number of VBs stained by the contrast solution between the QL and psoas minor muscles was significantly higher in group HV than group LV. The catheter tip was visualized in the retroperitoneal space in 1/16 and 2/10 hemiabdomens in phases 1 and 2, respectively. Rescue analgesia was required in 3/5 dogs during the postoperative period. The QL catheter placement technique appears feasible and may be included in a multimodal analgesic approach for dogs undergoing abdominal surgeries.

The quadratus lumborum (QL) block is an ultrasound-guided locoregional anesthesia technique which aims to provide analgesia to the abdomen. The main objective of this study was to assess a modified ultrasound-guided dorsal QL block in cat cadavers. For this purpose, a volume of 0.4 mL kg−1 of a mixture of iopromide and methylene blue was administered between the psoas minor muscle and the vertebral body (VB) of the first lumbar vertebra, and its distribution was assessed in thirteen cat cadavers. We hypothesized that this injection point would be feasible, offering a more cranial distribution of the injectate and a more consistent staining of the truncus sympathicus. The study was divided into two phases. Phase 1 consisted of an anatomical study (three cadavers were dissected). Phase 2 consisted of the ultrasound-guided administration of the injectate and the assessment of its distribution by computed tomography and anatomical dissection. The results showed a consistent distribution of contrast media within five (4–8) VBs from T10 to L5. Methylene blue stained three (2–6) rami ventrales, affecting T11 (10%), T12 (20%), T13 (60%), L1 (85%), L2 (95%) and L3 (65%). The truncus sympathicus was dyed in all cadavers with a spread of five (3–7) VBs. Finally, the splanchnicus major nerve was stained in all cadavers (100%). These results suggest that this technique could provide analgesia to the abdominal viscera and the abdominal wall, probably with the exception of the cranial aspects of the abdominal wall.

Background/Objectives : There is an ongoing debate about the most advantageous anesthesia technique for carotid endarterectomy (CEA). From an anesthesiologic perspective, locoregional anesthesia (LRA) appears to offer significant benefits. However, the learning curve and complication rates for anesthesiologists newly performing ultrasound-guided LRA for CEA remain unclear and are to be examined in greater detail in this study. Methods: This retrospective, single-center study included all consecutive LRA administrations for CEA following the introduction of this procedure at a district hospital in Germany from November 2013 to November 2017. Nine board-certified anesthesiologists, initially inexperienced in LRA for CEA but with prior experience in other ultrasound-guided peripheral nerve blocks (PNBs), received theoretical training and supervision during their first six combined deep and superficial cervical plexus blocks under ultrasound guidance. The primary endpoint was the incidence of insufficient block quality, indicated by pain and restlessness or the additional need for analgesics. Secondary endpoints included LRA-associated complications. Patients were divided into four groups based on the number of previously performed LRA procedures by the attending anesthesiologist. Results: In 83 patients, LRA was performed by initially inexperienced anesthesiologists. Group A (patients managed by anesthesiologists performing their 1st to 3rd cervical plexus blockades) included 21 patients, Group B (blockades 4-6) included 12 patients, Group C (blockades 7-9) included 9 patients, and Group D (≥10 blockades) included 41 patients, respectively. The overall complication rate was 22% (18/83). Insufficient block quality occurred in 18.1% of patients (15/83), resulting in three conversions to general anesthesia (3.6%). Additional complications included dysphagia (n = 2) and Horner's syndrome (n = 1). The incidence of insufficient block quality was significantly reduced ( p = 0.008) after performing the first three blockades. Conclusions: Ultrasound-guided cervical plexus block for CEA appears to be a rapidly learnable anesthesia technique for anesthesiologists experienced in other ultrasound-guided PNBs, with a low risk of complications. After three supervised blockades, the failure rate of LRA decreases significantly.

The QL block is a high-level locoregional anesthesia technique, which aims to provide analgesia to the abdomen. Several approaches of the QL block have been studied to find out which one allows a greater distribution of the injectate. The aim of this study is to compare the traditional interfascial QL block (IQL) with a new latero-ventral approach (LVQL). We hypothesize that this new approach could be safer and easier to perform, since the injectate is administered more superficially and further away from vital structures. Our second objective is to assess whether a higher volume of injectate (0.6 mL/kg) could reach the ventral branches of the last thoracic nerves, leading to a blockade of the cranial abdomen. Six thawed canine cadavers (12 hemiabdomens) were used for this purpose. Both approaches were performed in all cadavers. A combination of methylene blue/iopromide was administered to each hemiabdomen, randomly assigned to the LVQL or IQL. No differences were found regarding the ease of perform the LVQL with respect to IQL. The results show that both techniques reached the ventral branches from L1 to L3, although only the IQL consistently stained the sympathetic trunk (5/6 IQL vs. 1/6 LVQL). The use of a higher volume did not enhance a more cranial distribution of the injectate.

The quadratus lumborum (QL) block targets the fascial plane surrounding the QL muscle providing abdominal somatic and visceral analgesia. The extension of its analgesic effects is a subject of research, as it could not cover areas of the cranial abdomen in dogs. This study assesses in eight thawed canine cadavers, the distribution of high-volume injections (0.6 mL kg−1 of a mixture of methylene blue and iopromide) injected between the psoas minor muscle and the vertebral body of L1. Anatomical features of the area of interest were studied in two cadavers. In another six dogs, QL blocks were performed bilaterally under ultrasound-guidance. The distribution of contrast was evaluated by computed tomography (CT). Hypaxial abdominal muscles were dissected to visualize the dye spread (spinal nerves and sympathetic trunk) in 5 cadavers. The remaining cadaver was refrozen and cross-sectioned. CT studies showed a maximum distribution of contrast from T10 to L7. The methylene blue stained T13 (10%), L1 (100%), L2 (100%), L3 (100%), L4 (60%) and the sympathetic trunk T10 (10%), T11 (20%), T12 (30%), T13 (70%), L1 (80%), L2 (80%), L3 (60%) and L4 (30%). These findings may suggest that despite the high volume of injectate administered, this modified QL block could not produce somatic analgesia of the cranial abdomen, although it could provide visceral analgesia in dogs.