Advancements in Evidence-Based Analgesia in Exotic Animals

Comparison of conventional ligatures and a vessel sealing device for haemostasis during open ovariohysterectomy in rabbits

AIMS

To compare surgical times and rates of intra-operative and post-operative complications for open ovariohysterectomy (OVH) in female rabbits using conventional ligatures or a vessel sealing device (VSD) for haemostasis.

METHODS

Female pet rabbits (n = 23) presented for OVH for either desexing or treatment of reproductive disorders were randomly assigned to a conventional ligatures (CL) group (n = 12) or a LigaSure 5-mm (LS5) group (n = 11). In the CL group, the ovarian pedicles were ligated with a single surgeon's knot. After transection of the ovarian pedicles, the broad ligament was manually broken down along the uterine horns to their respective cervices. In the LS5 group, both ovarian pedicles and the broad ligaments were sealed with a LigaSure Dolphin Tip VSD with 5-mm forceps. All the rabbits were hospitalised for 24 hours after surgery. Two weeks after discharge, a clinical recheck examination was performed. Incision length, overall surgical time (from initial incision to completion of intradermal suturing), OVH time (from identification of the first ovary to transection of the vaginal vault), and intra- and post-operative complications were recorded and compared between groups, using the Student's t-test for normally distributed continuous data, the Wilcoxon-Mann-Whitney test for non-normally distributed continuous data and Pearson's χ2 test for categorical data.

RESULTS

The mean overall surgical time was 14.1 (SD 4.4) minutes. The surgery took 15.0 (SD 4.9) minutes in the CL group and 13.1 (SD 3.8) minutes in the LS5 group (p=0.10). The OVH time was shorter in the LS5 group (mean 4.2 (SD 0.9) minutes) than in the CL group (mean 6.3 (SD 1.7) minutes; p = 0.005). No intra-operative complications were encountered in the LS5 group. Haemorrhage occurred in three rabbits in the CL group. One rabbit in the LS5 group developed steatonecrosis post-operatively. There was no evidence of a difference in the proportion of rabbits that experienced intra- and post-operative complications (p = 0.25 and p = 0.94 respectively) between groups.

CONCLUSIONS

The use of a LigaSure 5-mm VSD and conventional ligatures during open OVH were both associated with similar overall surgical times and complication rates. The OVH times were shorter in the LS5 group compared to the CL group.

CLINICAL RELEVANCE

Use of the LigaSure 5-mm VSD allows efficient haemostasis while performing open OVH in female pet rabbits.

Psittacine Sedation and Anesthesia

Successful management of sedation/anesthesia of psittacine species relies on familiarity with their specific anatomy and physiology, and detailed knowledge of the recent advancements in applied pharmacology of the anesthetics and perianesthetic monitoring of cardiovascular and respiratory functions. Each sedation/anesthetic plan should be patient-specific, developed based on preexisting conditions, size, species, age, and estimated risk. Other key factors to improve safety, quality of perioperative care, and client satisfaction are anticipation of complications, extension of close monitoring to the recovery phase, multimodal analgesic approach, stress prevention/reduction, and transparent communication with the owner.

Care of the Geriatric Raptor

Despite falconry having been practiced for centuries and with a wealth of published material on the husbandry of captive raptors over that period, there is a paucity of published material on the care of the geriatric raptor. Raptors are often a long-lived species and can suffer a range of age-related conditions that may impact on their welfare. This article seeks to cover some of these conditions and look at welfare considerations in the management of geriatric raptors, including quality-of-life assessments and euthanasia decision making.

Injection techniques for auricular nerve blocks in the rabbit cadaver

OBJECTIVE

To describe the landmarks for localization and to determine the methodology and volume of methylene blue dye to adequately stain the auricular nerves in rabbit cadavers.

STUDY DESIGN

Prospective, randomized, cadaveric study.

ANIMALS

A total of 26 rabbit cadavers (Dutch-Belted and New Zealand White breeds).

METHODS

Part I: anatomical dissections were performed to identify the sensory auricular nerves and to establish the ideal injection approach and volume of dye required for nerve staining. Part II: a single injection technique using 0.1 mL kg^-1 dye was evaluated for staining the greater auricular nerve and two techniques (perpendicular and angled needle approaches) using 0.075 mL kg^-1 dye were evaluated for the auriculotemporal nerve. Dye spread was evaluated through cadaveric dissections and nerve staining graded using a 0-2 point scale. Injections were considered successful if the nerve was stained circumferentially. Cadavers were assessed for staining of the mandibular nerve owing to the close proximity to the auriculotemporal nerve. Fisher's exact test and mixed effects logistic regression model were used for statistical analysis.

RESULTS

The greater auricular nerve was stained in 24/27 (88.9%) injections. The auriculotemporal nerve was stained in 7/12 injections (58.3%) with the perpendicular needle approach; staining success increased to 80% (12/15 injections) with the angled needle approach; however, this difference was not statistically significant (p = 0.228). Mandibular nerve staining occurred on seven auriculotemporal injections with no statistically significant difference in the incidence of nerve staining between techniques.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggest that the auricular nerves in rabbit cadavers can be successfully located and stained using anatomic landmarks and the described injection techniques.

Orthopedics in Reptiles and Amphibians

Musculoskeletal disorders are a common cause for presentation of reptiles and amphibians to the veterinarian. A clinical approach to orthopedic cases starts with a thorough history and review of husbandry, and identification of any underlying or concomitant disease. Medical management is indicated for pathologic fractures. Traumatic fractures may require surgical intervention. Stabilization options include external coaptation and/or external and internal fixation. Special considerations must be given to shell fractures in chelonians. Many techniques used in mammalian practice can be applied to reptiles and amphibians, although some species may require prolonged healing times by comparison.

PHARMACOKINETICS OF ORAL GABAPENTIN IN CARIBBEAN FLAMINGOS ( PHOENICOPTERUS RUBER RUBER)

Gabapentin is a first-line treatment for neuropathic pain and adjunct anticonvulsant medication in humans and other species. Gabapentin may have advantages over other analgesics because of its broad therapeutic range with limited adverse effects and wide availability as an oral formulation. This study determined the pharmacokinetics of gabapentin in Caribbean flamingos ( Phoenicopterus ruber ruber) after a single-dose oral administration of either 15 mg/kg ( n = 6) or 25 mg/kg ( n = 6). Plasma gabapentin concentrations were determined using liquid chromatography with mass spectrometry, and pharmacokinetic analysis was performed using noncompartmental methods. Respectively for the 15 mg/kg and 25 mg/kg dose, mean peak plasma concentration ( C_max) was (mean ± pseudo SD) 13.23 ± 1.47 and 24.48 ± 5.81 μg/ml; mean time to peak plasma concentration ( T_max) was 0.50 ± 0.24 and 0.56 ± 0.28 hr; mean area under the curve (AUC) was 76.0 ± 26.3 and 114.7 ± 27.5 hr·μg/ml; and mean terminal half-life ( T_1/2) was 3.39 ± 0.90 and 4.46 ± 1.12 hr. Based on the results of this study, gabapentin dosed at 25 mg/kg orally in most Caribbean flamingos is likely to maintain plasma concentrations above the therapeutic range established for humans for approximately 12 hr.