Abstract
OBJECTIVE
Use finite element analysis to evaluate the biomechanical effects of spinal decompression procedures in healthy Beagle dogs, comparing individualized mini-hemilaminectomy–corpectomy (iMHC), mini-hemilaminectomy, partial lateral corpectomy (PLC), and hemilaminectomy.
METHODS
A finite element model of the L1-L2 functional spinal unit was generated using CT data. For each decompression model, loads were applied in 0.2-Nm steps (maximum, 2.0 Nm) in 6 directions: flexion, extension, right and left lateral bending, and right and left axial rotation. The L1 spinous process tip displacement angle was quantified numerically.
RESULTS
Among the 4 techniques, mini-hemilaminectomy exhibited the smallest displacement angles across all directions. Hemilaminectomy exhibited the largest displacement angles in extension, flexion, right rotation, and left rotation across all techniques. Left and right lateral bending displacement angles were marginally larger for iMHC than for hemilaminectomy at 0.4 Nm; however, at 2.0 Nm, displacement angles were similar.
CONCLUSIONS
Mini-hemilaminectomy minimizes functional spinal unit instability to the greatest extent. Hemilaminectomy is more unstable than iMHC and PLC in flexion, extension, and rotation. Mini-hemilaminectomy–corpectomy and PLC are more unstable than hemilaminectomy in lateral bending, with iMHC being slightly more unstable than PLC or nearly equal.
CLINICAL RELEVANCE
Mini-hemilaminectomy minimizes instability to the greatest extent in cases of ventrolateral spinal compression. In cases of ventral spinal compression, iMHC may be preferable to PLC for providing equivalent stability without impeding spinal cord visualization, but both techniques can cause instability depending on loading direction, so careful attention to postoperative instability is necessary when excessive vertebral body resection is involved.
Abstract
OBJECTIVE
To utilize sidestream dark field video microscopic technology to evaluate the endothelium in a canine hemorrhagic shock and resuscitation model.
METHODS
6 purpose-bred adult dogs were anesthetized, instrumented, and subjected to hemorrhagic shock from September 2021 through June 2022. Each dog was resuscitated with 5 resuscitation strategies in an experimental crossover design study: (1) lactated Ringer’s solution (LRS) and hydroxyethyl starch (HES) solution; (2) canine chilled whole blood (CWB); (3) canine fresh frozen plasma (FFP) and packed RBCs (pRBC); (4) canine freeze-dried plasma (FDP) and hemoglobin-based oxygen carrier (HBOC); or (5) HBOC/FDP and canine lyophilized platelets. Sidestream dark field video microscopic evaluation was performed at 5 time points: commencement, after hemorrhage, after shock, after resuscitation (T135), and conclusion (T180).
RESULTS
There was a significant difference between the perfused boundary region (PBR) measurements when comparing the LRS/HES resuscitation arm to the CWB and FFP/pRBC resuscitation arms at T180. A significant difference in PBR was appreciated in the LRS/HES arm at T135 and T180 compared to its baseline. No other significant differences in PBR were appreciated when resuscitation arms were compared longitudinally or to each other.
CONCLUSIONS
Shelf-stable blood products preserved the endothelial glycocalyx similarly to CWB and pRBC/FFP as evaluated by sidestream dark field video microscopy. Lactated Ringer and HES solutions did not adequately preserve the endothelial glycocalyx compared to CWB and pRBC/FFP.
CLINICAL RELEVANCE
Shelf-stable blood products are a viable option to preserve the endothelial glycocalyx when used during hemorrhagic resuscitation in dogs.
Abstract
OBJECTIVE
Cruciate ligament rupture (CR) in Labrador Retrievers is a complex polygenic disease with high heritability. The environmental contribution to CR risk remains poorly characterized. An accurate genetic risk test for CR in the Labrador Retriever has been developed. This enables evaluation of environmental risk with knowledge of genetic disease predisposition through study of dogs with phenotypic disease status that is discordant with their genetic risk. The objective of this study was to identify environmental factors that contribute to CR in Labrador Retrievers through evaluation of dogs with clinical phenotypes that are discordantly predicted with the use of genetic markers.
METHODS
Dogs were prospectively recruited between January 2013 and December 2022. To study discordant subjects, case dogs with a posterior risk probability value < 0.75 and control dogs with a posterior risk probability of > 0.25, determined with the use of an average of 8 statistical models, were selected. The environmental factors investigated were neuter status, age of neuter, withers height measured at the dorsal-most ridge between the scapulae, weight, body mass index, and athletic activity.
RESULTS
Ninety three dogs were discordant: 58 dogs were discordant CR cases, and 35 dogs were discordant CR controls. Neutering before 12 months of age was a significant risk factor for CR development. Sex, neuter status, or status as an athlete was not associated with CR risk.
CONCLUSIONS
Neutering before 12 months of age influences risk of CR in Labrador Retrievers.
CLINICAL RELEVANCE
This information can inform management decisions about Labrador Retrievers regarding age of neutering, body condition, and athletic activity. The primary factor influencing CR development in Labrador Retrievers is polygenic intrinsic genetic risk.
Abstract
OBJECTIVE
To measure and model concentrations of the analgesic L-carvone, a natural component of spearmint, over time when administered IM to sheep and to characterize L-carvone’s effects on CBCs and clinical biochemistry panels.
METHODS
L-carvone formulated as a 50% solution (v/v) in ethanol and propylene glycol was administered at 71.6 mg/kg IM, split between each semitendinosus muscle in 6 sheep. Venous blood was sampled over 24 hours, and plasma was separated by centrifugation. Additional blood was collected for CBC and serum biochemical analysis, and tissues were sampled after euthanasia. L-carvone concentrations in plasma and tissue homogenates were measured using HPLC-MS-MS. Plasma pharmacokinetic data were described using a nonlinear mixed effects model. Complete blood count and biochemistry data were compared to baseline values using repeated-measures ANOVA and Holm-Šidák tests (P < .05).
RESULTS
Maximum plasma concentrations ranged from 0.28 to 1.93 µg/mL and occurred within 9 to 15 minutes after injection. Pharmacokinetics were best described using 2 compartments. Elimination half-life was 33.7 minutes and 390.2 minutes in the central and peripheral compartments, respectively. Mild increases in neutrophil count and significant increases in creatinine kinase and aspartate aminotransferase were associated with injection site myonecrosis. No physical examination, behavioral, or other clinically significant laboratory changes were noted.
CONCLUSIONS
Intramuscular L-carvone exhibits rapid time to peak concentration, relatively slow plasma elimination, and low tissue concentrations after 24 hours.
CLINICAL RELEVANCE
L-carvone exhibits a favorable pharmacokinetic profile for an analgesic drug. A new L-carvone formulation or administration route is needed to reduce inflammation and necrosis at the injection site.
Abstract
OBJECTIVE
To investigate the prevalence and severity of intervertebral disc (IVD) degeneration (IVDD) throughout the spine of young, middle-aged, and old asymptomatic cats; identify differences between the cervical, thoracic, and lumbar spine; and investigate the influence of sex and neuter status on the prevalence of feline IVDD.
METHODS
60 cadavers were collected from asymptomatic cats and subdivided into 3 age groups: young (≥ 1 to < 6 years), middle aged (≥ 6 to < 12 years), and old (≥ 12 years). T2 weighted sagittal MRI studies of the spine were obtained. Each IVD was graded according to the modified Pfirrmann grading for feline IVDD. Cumulative link mixed models were used to analyze the significance of spinal region, age, sex, and neuter status on the degenerative state of the IVDs.
RESULTS
A total of 1,544 IVDs were evaluated; 884 (57.3%), 425 (27.5%), 147 (9.5%), 82 (5.3%), and 6 (0.4%) were graded Pfirrmann 1, 2, 3, 4, and 5, respectively. Irrespective of spinal region, middle-aged cats (OR, 4.03; P < .01) and old cats (OR, 12.5; P < .01) had significantly higher odds for IVDD compared to young cats. For old cats, thoracic (OR, 4.44; P < .01) and cervical IVDs (OR, 2.76; P < .01) had significantly higher odds of degenerating compared to lumbar IVDs. No significant effect of sex (P = .81) and neuter status (P = .61) was found.
CLINICAL RELEVANCE
The prevalence of feline IVDD significantly increases with progressive age, with the thoracic and cervical IVDs showing the highest odds for degeneration. However, extreme stages of IVDD were only occasionally observed.
Abstract
OBJECTIVE
To characterize cystometry in conscious and anesthetized sheep, including bladder response to sacral root electrical stimulation, thereby providing a baseline set of values.
METHODS
Single-fill cystometries were repeated in adult mule ewes both conscious (n = 5) and under general anesthesia (18) using a commercial system. Parameters including bladder capacity, detrusor (bladder) pressure, urethral opening pressure, bladder compliance, number of nonvoiding detrusor contractions, and bladder pressure change in response to electrical stimulation of the sacral roots under general anesthesia are reported. Pubmed, Embase, and Web of Science databases were searched for studies relating to ovine cystometry, and a systematic review was conducted.
RESULTS
In awake sheep, mean ± SD bladder capacity was 79.6 ± 32.2 mL, urethral opening pressure was 26.0 ± 10.7 cm H2O, and compliance was 3.5 ± 1.9 mL/cm H2O. Peak detrusor pressures during micturition reached 57.7 ± 28.3 cm H2O. In anesthetized animals, mean bladder capacity (endpoint, 50 cm H2O) was 333 ± 191 mL, and mean bladder compliance was 7.7 ± 4.9 mL/cm H2O. Values for these parameters from our systematic review are presented for comparison and reference. Electrical stimulation of the second and third sacral roots caused a greater increase in detrusor pressure than stimulation of the first and fourth sacral roots.
CONCLUSIONS
We present a comprehensive set of data for normal cystometry parameters in sheep, including the first report of detrusor response to sacral root stimulation in anesthetized sheep.
CLINICAL RELEVANCE
This report provides a valuable set of baseline values for a potential translational model of value to neurourologic research and may be a useful reference for clinicians.
Abstract
OBJECTIVE
To describe clinical findings, complications, and short- and long-term outcomes associated with colonic torsion and volvulus in dogs.
ANIMALS
28 client-owned dogs.
CLINICAL PRESENTATION
Multi-institutional, retrospective study. Medical records were searched for dogs of any age, body weight, sex, and breed that underwent surgery for colonic torsion and volvulus. Collected data included signalment, previous history, preoperative findings, time until surgery, intraoperative findings, postoperative complications, length of hospitalization, survival to discharge, and outcomes.
RESULTS
28 dogs were included. Thirteen of 28 dogs (46.4%) had preexisting gastrointestinal conditions. Nine of 28 dogs (32.1%) had a gastropexy performed prior to presentation. Ten dogs (35.7%) were found to have a resolution of colonic torsion and volvulus at the time of the surgery. All but 1 dog (27 of 28 [96.4%]) survived to discharge. Two dogs died during the postoperative period, yielding a mortality rate of 7.1%. Postoperative complications were noted in 9 dogs (9 of 28 [32.1%]). Long-term follow-up information was available in 16 of 28 dogs (57%). Among 16 dogs with at least 6 months’ follow-up, all dogs (16 of 16 [100%]) were alive at 6 months postoperatively. Two dogs developed mesenteric torsion after the initial surgery.
CLINICAL RELEVANCE
Dogs with colonic torsion and volvulus undergoing surgery can have an excellent survival-to-discharge ratio with a low mortality rate. Surgeons should not be prompted to euthanize or assume a guarded prognosis solely on the basis of the intraoperative appearance of the bowel and should consider all factors prior to making decisions. Owners should be informed of the risk of developing further torsional diseases after surgery.
Abstract
OBJECTIVE
To evaluate the feasibility and reliability of early ultrasound diagnosis for postsurgical bowel dehiscence and find the most reliable ultrasound criteria for dehiscence identification. Additionally, to determine the impact of early ultrasound detection of leakage in terms of survival and duration of hospitalization. Finally, to assess the need for systematized screening or checkup of the population at risk of dehiscence only.
ANIMALS
31 cats and 83 dogs.
METHODS
A retrospective, records-based study was performed on 83 dogs and 31 cats (114 total) undergoing small intestinal surgery. Epidemiologic data, clinical signs, surgical procedures, pre- and postoperative ultrasound findings at 48 to 96 hours, hospitalization duration, complications, and general outcomes were recorded. Univariate and multivariate analyses were used to identify ultrasound findings associated with dehiscence.
RESULTS
Dehiscence was suspected by ultrasound for 0 of 31 cats and 7 of 83 dogs (2 of 49 for enterotomy and 5 of 34 for enterectomy). Every suspected dehiscence was confirmed during revision surgery except one enterectomy revision, which was declined by the owner. Neither this case nor those without ultrasound evidence of dehiscence developed clinical signs of intestinal leakage. Direct visibility of wall discontinuity, presence of gas bubbles, and liquid in vicinity of the intestinal surgical site were statistically associated with early dehiscence. Survival rate after the second surgery was 83%. Median hospitalization time after the second surgery for dehiscence was 2 days (minimum, 2 days; maximum, 4 days).
CLINICAL RELEVANCE
Postoperative ultrasound examination between 48 and 96 hours after intestinal surgery allows early and sensitive detection of intestinal dehiscence. Survival rate after revision surgery was significantly higher than that associated with septic peritonitis.
Abstract
OBJECTIVE
To explore the differences in outcomes between dogs with intrahepatic portosystemic shunts (IHPSSs) partially occluded with a mattress suture with pledgets or attenuated with cellophane banding.
METHODS
74 dogs with IHPSSs were included in this retrospective study. Medical records between January 2000 and February 2020 were evaluated for information on dogs undergoing laparotomy with cellophane banding (group C) or mattress suture with pledgets (group P) for treatment of IHPSSs, including specific outcomes of survival time, persistence of clinical signs, and necessity of continued medical management. Primary veterinarians and owners were contacted for long-term follow-up.
RESULTS
51 dogs were entered in group C and 23 in group P. The duration of surgery was 154.6 minutes (136.3 to 170 minutes) for group C and 154.9 minutes (128.9 to 180.9 minutes) for group P. The short-term mortality rate was 2% for group C and 4% for group P. Dogs in group C had a median survival time of 3,537 days, while dogs in group P had a median survival time of 2,141 days. In the long term, dogs in group P received more medications than dogs in group C, but the distribution of the quality-of-life score was not different.
CONCLUSIONS
Mattress suture with pledgets can be used as an alternative to cellophane banding.
CLINICAL RELEVANCE
For dogs with IHPSSs where full surgical dissection for placement of cellophane band is not possible, partial occlusion of the shunt with a mattress suture with pledgets is a viable option with acceptable long-term outcomes.
