An Ultrasound-Guided Latero-Ventral Approach to Perform the Quadratus Lumborum Block in Dog Cadavers

Ultrasound-guided quadratus lumborum block in sheep: A cadaveric study

This prospective anatomical study aimed to establish an ultrasound-guided technique to the quadratus lumborum (QL) plane in sheep cadavers. Thirteen cadavers, weighing less than 117 kg, were included. In phase 1, one cadaver underwent dissection and two cadavers underwent 3D computed tomographic reconstruction for anatomical evaluation of the thoracolumbar region. In phase 2, two cadavers were used to compare two ultrasound techniques to the QL plane: lateral to the QL muscle with a transversal approach (LQL) and transmuscular between QL and psoas muscles with a longitudinal approach (TQL). For LQL, the reference was the first lumbar transverse process, whereas for TQL, it was the intertransverse region between the first and second lumbar vertebrae. The needle was advanced in-plane towards the specific target for each technique and a total of four injections were performed using 0.4 ml kg-1 of a dye-lidocaine solution. In phase 3, 10 cadavers received bilateral LQL injections (n = 20). All cadavers were then dissected to evaluate spread of dye. In phase 2, following LQL injections, no dye was observed in undesired locations; however, the dye was noted in the retroperitoneal space (1/2) after TQL injections. In phase 3, the 13th thoracic, first, second, third lumbar nerves, and sympathetic trunk segments were stained in 80%, 95%, 100%, 45% and 35% of the injections, respectively. In conclusion, the LQL technique was feasible, allowing staining of the spinal nerves innervating the cranial abdomen in sheep cadavers. Further studies in live animals are warranted.

Use of Caudal Quadratus Lumborum Block with Ropivacaine as Part of an Opioid-Free Analgesic Protocol in Dogs Undergoing Orchiectomy: A Randomized Trial

In veterinary medicine, the use of loco-regional anesthesia techniques is increasing. The Quadratus Lumborum block (QL) is an interfascial loco-regional technique that involves the release of local anesthetic (LA) between the Quadratus Lumborum and the Small Psoas (Pm) muscle. The study aims to evaluate the effect of the QL block on reducing the total amount of opioids in dogs undergoing pre-scrotal orchiectomy. A group of 36 dogs was enrolled in a randomized blinded study. The animals were divided into two groups: 18 in the experimental group (QL) and 18 in the control group (C). The QL group received 0.4 mL kg-1 of ropivacaine 0.5% for each hemiabdomen (total amount of 3 mg kg-1 of ropivacaine, 1.5 mg kg-1 per side). The C group was brought into the operating room (OR) after receiving the same clipping as the QL group. In the intraoperative period, opioid consumption in the QL group was significantly lower than in the C group. No differences were found in the post-operative phase. No side effects were reported when performing the QL technique. The QL block performed at the level of L6 appears to be a valid approach to reducing opioid use in dogs undergoing orchidectomy with a pre-scrotal surgical approach.

Description and Evaluation of Dye and Contrast Media Distribution of Ultrasound-Guided Rectus Sheath Block in Cat Cadavers

The rectus sheath block is an ultrasound-guided anaesthetic technique which aims to provide analgesia to the abdominal midline. This study aimed to assess the distribution of 0.4 mL kg-1 of a mixture of methylene blue and iopromide injected into each hemiabdomen in the internal rectus sheath in cat cadavers. We hypothesise that this technique would be feasible and would cover the rami ventrales of the last thoracic and the first lumbar spinal nerves. The study was divided into two phases. Phase 1 aimed to study the anatomical structures of the ventral abdominal wall (four cats were dissected). Phase 2 (ten cadavers) consisted of an ultrasound-guided injection of the mixture mentioned above and the assessment of its distribution by computed tomography and anatomical dissection. The results showed the staining of the cranioventral abdominal wall with a craniocaudal spread of four (three to eight) vertebral bodies. Methylene blue stained three (one to four) rami ventrales, affecting T10 (60%), T11 (100%), T12 (90%), T13 (50%) and L1 (5%). Based on these results, it could be stated that this technique could supply anaesthesia to the midline of the abdominal midline cranial to the umbilicus in clinical patients, but it may not be able to provide anaesthesia to the middle and caudal midline abdominal region.

Ultrasound-guided caudal quadratus lumborum block combined with the greater ischiatic notch plane block as motor-protective analgesia for the pelvic limb in dogs

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.

Modified Ultrasound-Guided Dorsal Quadratus Lumborum Block in Cat Cadavers

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.