Lumbar Epidural: Anatomical and Clinical Study in Dogs Submitted to Ovariohysterectomy

The impact of the transversus abdominis plane block (TAP) on stress response measured through the complete blood- derived inflammatory markers

This study aims to evaluate the effect of the transversus abdominis plane (TAP) block on the blood cells and the inflammatory markers neutrophil- to- lymphocyte ratio (NLR), platelet- to- lymphocyte ratio (PLR), and systemic immune- inflammation index (SII) after the laparoscopic ovariectomy (LapOV) in dogs. 72 healthy bitches undergoing LapOV were randomly allocated to the no- TAP group of dogs under inhaled anesthesia (IA), the TAP- S group (IA and TAP with saline), and the TAP- B group (IA and TAP with bupivacaine). The NLR, PLR, and SII were calculated 1 h before ovariectomy (T0) and at 2-3 h (T1), 6-8 h (T2), and 20-24 h (T3) post- surgery. The number of dogs requiring postoperative analgesic rescue with buprenorphine and the doses administered in each group were recorded. Significant changes were observed in all groups' postoperative NLR, PLR, and SII over time. Between groups, no differences were observed in any of the ratios at any control point (NLR at T0-T3: p = 0.17, 0.36, 0.80, and 0.95; PLR at T0-T3: p = 0.70, 0.62, 0.21, 0.87; SII at T0-T3: p = 0.29, 0.65, 0.09, and 0.34). A significantly lower number of dogs required analgesic rescue in the TAP-B group (p = 0.0001) and a lower number of doses were administered (p = 0.001). There is no difference in the inflammatory response measured through the complete blood- derived inflammatory markers after the LapOV in dogs when the postoperative pain is managed entirely with opioids or with the TAP block with bupivacaine. The hydrodissection associated with the TAP block technique does not increase the inflammatory response.

Comparison between Bilateral Ultrasound-Guided Quadratus Lumborum Block and Sacrococcygeal Epidural in Cats Undergoing Ovariectomy

BACKGROUND

Ultrasound-guided quadratus lumborum block (QLB) and sacrococcygeal epidural anaesthesia (ScE) have been used for neutering cats, providing effective pain relief.

OBJECTIVES

To compare the effects of the QLB with those of ScE in cats undergoing ovariectomies.

METHODS

Feral cats undergoing ovariectomy were premedicated with dexmedetomidine (20 μg kg-1) and methadone (0.2 mg kg-1) intramuscularly. Anaesthesia was induced with 2-4 mg kg-1 of propofol intravenously and maintained with isoflurane in oxygen. The cats were randomly allocated to the groups QLB (bilateral QLB with 0.4 mL kg-1 of 0.25% bupivacaine) and ScE (0.3 mL kg-1 of 0.25% bupivacaine). Hemodynamic data and analgesia rescue were collected at four intraoperative periods. The pain scale and motor block were assessed in both groups during the postoperative period.

RESULTS

The ScE results in increased hypotension, prolonged extubation time, and higher postoperative motor block than the QLB (p < 0.05). The QLB and ScE groups required a similar number of intraoperative rescues and presented the same postoperative pain scale classification.

CONCLUSIONS

The QLB with 0.25% bupivacaine is a potential alternative to ScE with 0.25% bupivacaine in perioperative pain management in elective cat ovariectomy. The QLB promoted less hypotension and postoperative motor block when compared with the ScE group.

Clinical Assessment of Introducing Locoregional Anaesthesia Techniques as Part as the Intraoperative Analgesia Management for Canine Ovariohysterectomy in a Veterinary Teaching Hospital

This study compared four methods to provide intraoperative analgesia during canine ovariohysterectomy in a veterinary teaching hospital. A retrospective study was designed to assess the nociceptive response, cardiorespiratory stability, quality of recovery and complications of four analgesic protocols: epidural analgesia (EPIDURAL group), Quadratus Lumborum block (QLB group), Transversus Abdominis Plane block (TAP group), and just systemic analgesia (GENERAL group). Undergraduate students carried out all the loco-regional techniques under the direct supervision of a qualified anaesthetist. A total of 120 cases met the inclusion criteria and were included in the study and were distributed as follows: 22, 27, 32 and 39 cases with EPIDURAL, GENERAL, QLB and TAP groups, respectively. Data were analysed with statistical software R using different statistical methods. Significant differences among groups were defined as p < 0.05. Based on our results, all the groups needed the same number of rescue analgesia during the intra-operative period. The use of loco-regional techniques anticipated a better quality of recovery compared with the general group. The EPIDURAL group showed a statistically lower expired fraction of sevoflurane. No differences were found regarding complications. In conclusion, these four analgesic methods are suitable and safe to be performed for canine ovariohysterectomy, although loco-regional techniques might have some advantages.

Local and Regional Anaesthetic Techniques in Canine Ovariectomy: A Review of the Literature and Technique Description

Simple Summary

This review stems from a general trend of increasing attention toward surgical nociception in the veterinary field. Indeed, veterinarian anaesthetists are becoming more careful in relieving perioperative nociception, improving the analgesic protocols and therefore optimising surgical outcomes. Canine ovariectomy is a common surgical procedure with a moderate level of pain. Therefore, intraoperative analgesia is very important because pain causes various systemic inflammatory effects that slow patient recovery. This review aims to collect all recent information about local and regional anaesthetic/analgesic techniques in a review of the literature describing the technique utilised. In addition, the present review aims to provide practical guidelines for veterinary practitioners to improve the anaesthetic techniques in canine neutering through an overview of the available literature. In fact, the methods described, considering the relative simplicity of execution, can be used in daily routine practice.

Abstract

Canine ovariectomy is an elective surgery with a moderate level of pain. Despite its relative simplicity, it requires surgical pain management. This study aimed to collect all recent information about local and regional anaesthetic/analgesic techniques in a review of the literature describing the technique utilised. The various procedures described in this review use local anaesthetics to improve analgesia in the routine systemic anaesthetic protocol. The approach described in this paper is called multimodal analgesia and is used in addition to the normal standard anaesthetic protocol. These techniques proved effective in minimising responses to the surgical stimulus and ensured adequate intraoperative and postoperative analgesia. The routine use of multimodal analgesia is considered a useful alternative for pain management in canine ovariectomy, in that it minimises patient suffering, improves the recovery of rescue analgesia, increases drug savings, and improves animal outcomes. In addition, the use of these local and regional techniques ensures satisfactory analgesic coverage that lasts for the first hours postoperatively.

Postoperative Acupuncture is as Effective as Preoperative Acupuncture or Meloxicam in Dogs Undergoing Ovariohysterectomy: a Blind Randomized Study

Background

Acupuncture has the same analgesic effect as non-steroidal antiinflammatory drugs and opioids. It is challenging to perform preoperative acupuncture in unmanageable animals, while the residual postoperative anesthetic effect facilitates the performance of acupuncture postoperatively.

Objectives

To compare preoperative acupuncture or meloxicam versus postoperative acupuncture for postoperative analgesia after ovariohysterectomy.

Methods

This is a horizontal prospective positive control blind randomized experimental study. Thirty-six dogs were randomly divided into three groups: GA (preemptive acupuncture), GPA (postoperative acupuncture), and GM (meloxicam 0.2 mg/kg IV preoperatively). After sedation with acepromazine (0.05 mg/kg IM), anesthesia was induced with propofol (5.3 ± 0.3 mg/kg) and maintained with isoflurane/O2. Fentanyl (2 μg/kg, IV) was administered immediately before surgery. Bilateral acupuncture was performed at acupoints Large intestine 4, Spleen 6, and Stomach 36 for 20 minutes, before (GA) or immediately after surgery (GPA). Pain was evaluated by an observer blind to the treatment using the Glasgow scale before and for 24 hours after ovariohysterectomy. Dogs with a score ≥ 6 received rescue analgesia with morphine (0.5 mg/kg IM). Nonparametric data were analyzed by the Kruskal-Wallis test, followed by Dunn's test and parametric data by ANOVA followed by Tukey's test.

Results

Two GA and one GPA dogs received rescue analgesia once. Two GM dogs received rescue analgesia and one of those was treated again twice. There were no differences in the number of dogs receiving rescue analgesia between groups (p = 0.80).

Conclusion

Postoperative acupuncture was as effective as preoperative acupuncture or meloxicam in female dogs undergoing ovariohysterectomy.

An Observational Survey Study on the Use of Locoregional Anaesthesia in Non-Conventional Species: Current Practice and Potential Future Developments

The objectives of this study were to investigate the current attitudes of veterinarians towards the use of locoregional anaesthesia in non-conventional animal species and to identify areas for future useful research on this topic. A questionnaire was circulated online. A total of 417 veterinarians, including American and European specialists/specialists-in-training in both zoological medicine and anaesthesia/analgesia (ACZM/ECZM and ACVAA/ECVAA), participated in the study. Fifty-nine percent of respondents performed locoregional anaesthesia in rabbits, with intratesticular injections and local infiltration being the most commonly-reported techniques. ACZM/ECZM specialists reportedly performed dental blocks in rabbits more frequently than ACVAA/ECVAA specialists (p = 0.030). Forty percent of respondents performed locoregional anaesthesia in rodents, with intratesticular injections, topical/splash blocks and local infiltration being the most commonly reported techniques. The proportions of respondents who reportedly used locoregional anaesthesia in ferrets, birds and reptiles were 37.9%, 34.5% and 31.2%, respectively. The use of Tuohy (p < 0.001) and spinal needles (p < 0.001), as well as of ultrasonography (p = 0.009) and nerve-stimulators (p < 0.001), was more common among ACVAA/ECVAA compared to ACZM/ECZM specialists. Major topic areas for future research were identified as dental block techniques for rabbits and rodents and blocks for the wings of birds.

Evaluation of Quadratus Lumborum Block as Part of an Opioid-Free Anaesthesia for Canine Ovariohysterectomy

Simple Summary

The aim of this study was to assess an anaesthetic protocol involving the quadratus lumborum block (QLB) for canine ovariohysterectomy. Ten healthy dogs were included. Anaesthetic protocol consisted of medetomidine and meloxicam, induction of anaesthesia with propofol and maintenance with sevoflurane in oxygen/medical air. The QLB was performed at the level of L₁–L₂ injecting 0.4 mL kg⁻¹ of 0.25% bupivacaine/iohexol per side. Computed Tomography (CT) was performed before and after surgery. Fentanyl was administered as rescue analgesia during surgery. The Short Form of The Glasgow Composite Pain Scale and thermal threshold (TT) at the level of the humerus, T₁₀, T₁₃ and L₃ were assessed before premedication and every hour postoperatively. Methadone was given as rescue analgesia when it was needed. CT images showed spreading of a median (range) of 3 (2–5) vertebrae, without differences between preoperative and postoperative images. One out of ten dogs needed intraoperative rescue analgesia. Pain score was less than 4/24 in all the animals until four hours after surgery. TT showed significative increase in all the areas tested apart from the elbow 30 min after the recovery. The QLB provides additional analgesia for canine ovariohysterectomy.

Abstract

Quadratus lumborum block (QLB) is used to provide analgesia for abdominal surgery in humans. The aim of this study was to assess an anaesthetic protocol involving the QLB for canine ovariohysterectomy. Ten dogs were included. Anaesthetic protocol consisted of premedication with IM medetomidine (20 μg kg⁻¹) and SC meloxicam (0.1 mg kg⁻¹), induction with propofol to effect, and maintenance with sevoflurane in oxygen/medical air. QLB was performed injecting 0.4 mL kg⁻¹ of 0.25% bupivacaine/iohexol per side. Computed Tomography (CT) was performed before and after surgery. Fentanyl was administered as rescue analgesia during surgery. The Short Form of The Glasgow Composite Pain Scale and thermal threshold (TT) at the level of the elbow, T₁₀, T₁₃ and L₃ were assessed before premedication and every hour postoperatively. Methadone was given as rescue analgesia postoperatively when pain score was >3. A Yuen’s test on trimmed means for dependent samples was used to analyse the data (p < 0.05). CT images showed spreading of the contrast/block for a median (range) of 3 (2–5) vertebrae, without differences between preoperative and postoperative images. One dog needed rescue analgesia during surgery. Pain score was less than 4/24 in all the animals during the first 4 h after surgery. TT showed a significant increased signal in all the areas tested, apart from the humerus, 30 min after surgery. The QLB may provide additional analgesia for canine ovariohysterectomy. Further studies are needed to assess the specific contribution of the QLB in abdominal analgesia.

Mathematical Models for the Skin to Lumbosacral Epidural Distance in Dogs: A Cadaveric Computed-Tomography Study

This study aimed to validate previously published computed tomography (CT) derived mathematical equations with the true skin to lumbosacral epidural distance (SLED) in dog cadavers. Phase 1: The lumbar region of 11 dog cadavers were scanned in sternal recumbency to determine the effect of cranial, neutral, and caudal pelvic limb positioning on the CT derived lumbosacral epidural distance (CLED). Phase 2: The epidural space was determined using contrast epidurography, and the SLED was analysed against the mathematical equations using a body condition score (BCS) and either the cadaveric occipital-coccygeal length (OCL) (Equation (1): = 7.3 + 0.05*OCL + 16.45*BCS) or the ilium wing distance (IWD) (Equation (2): = 3.5 + 0.56*IWD + 16.6*BCS). There were no differences detected between the pelvic limb positions and the CLED. Both equations demonstrated strong correlations (Equation (1): r = 0.7196; Equation (2): r = 0.7590) with the SLED. The level of agreement was greater for Equation (1) than with Equation (2) (concordance coefficient 0.6061 and 0.3752, respectively). Equation (1) also demonstrated a closer fit to the concordance line compared with Equation (2) (bias correction factor 0.8422 and 0.4960, respectively). Further studies in live anaesthetised dogs will help to determine the usefulness of the pre-procedural knowledge when performing lumbosacral epidurals.