Computed tomographic evaluation of cervical vertebral canal and spinal cord morphometry in normal dogs

The height, width, and cross-sectional area of the vertebral canal and spinal cord along with the area ratio of spinal cord to vertebral canal in the cervical vertebra were evaluated in images obtained using computed tomography (CT). Measurements were taken at the cranial, middle, and caudal point of each cervical vertebra in eight clinically normal small breed dogs (two shih tzu, two miniature schnauzers, and four mixed breed), 10 beagles, and four German shepherds. CT myelography facilitated the delineation of the epidural space, subarachnoid space, and spinal cord except at the caudal portion of the 7th cervical vertebra. The spinal cord had a tendency to have a clear ventral border in the middle portion of the vertebral canal and lateral borders near both end plates. The height, width, and area of the vertebral canal and spinal cord in the cervical vertebra were increased as the size of dog increased. However, the ratio of the spinal cord area to vertebral canal area in the small dogs was higher than that of the larger dogs. Results of the present study could provide basic and quantitative information for CT evaluation of pathologic lesions in the cervical vertebra and spinal cord.     

Evalution of Age as a Risk Factor For Perianesthetic Morbidity and Mortality in the Dog

This study was intended to determine if age is a risk factor for perianesthetic morbidity/mortality in dogs and to identify other factors that may be important. A prospectivecohort study compiled data from 942 dogs (477 females; 465 males) ≥6 months undergoing inhalation anesthesia for≥30 minutes. were included. Serious perianesthetic complications occurred in 79 dogs. Logistic regression used a final model contanining age and ASA grade and showed a significant estimated odds ratio (O) for old vs young or middle-aged dogs of 1·89 (95% CI: 1·05,3·38). The Ofor ASA grade increased significantly with grade — ASA grade 3:1or2 = 3.4, ASA grade 4:1or2 = 7·1, and ASA grade 5:1or2 =18·8. Thus, old dogs were nearly twice as likely to develop serious perianesthetic complications, even when accounting for ASA grade. However, conditions that increased ASA assessment by one grade had more impact on increasing the likelihood of serious perianesthetic complete.     

Predictors of outcome in dogs undergoing thoracic surgery (2002–2011)

ObjectiveTo evaluate mortality in a canine population undergoing thoracic surgery and identify factors which may be associated with outcome.Study designRetrospective cohort study.Animals286 dogs anaesthetized for thoracic surgery at the Royal Veterinary College between June 2002 – June 2011.MethodsVariables examined included: signalment; ASA status; nature of disease; presence of co-morbidities; pre-anaesthetic oxygen requirement; surgical approach; anaesthesia management [anaesthetic agents; requirement for thoracocentesis; central venous pressure measurement; duration of surgery and anaesthesia; use of colloids, blood products, inotropes or neuromuscular blocking agents (NMBA)]. Outcome was defined as either non-survival to 24 hours after surgery or (having survived to 24 hours) to discharge. Univariate and multivariable logistic regressions were performed to identify risk factors associated with non-survival.ResultsOverall non-survival (excluding those euthanased) to discharge was 5.9%. Non-survival was 2.2% at 24 hours and 3.6% at time of discharge. Non-survival to 24 hours was associated with pre-anaesthetic oxygen requirement (odds ratio (OR) 12.2 [95% CI 1.8–84.5]) and NMBA use (OR 9.6 [95% CI 1.6–57.9]). Non-survival to discharge was associated with surgical duration, with surgeries >180 minutes having OR 16.9 [95% CI 2.0–144.0] compared to surgeries ≤90 minutes and blood product use (OR 4.6 [95% CI 1.3–14.6]). No association was found between ASA category and non-survival at 24 hours (OR 1.4 [95% CI 0.2–11.7]) or discharge (OR 4.4 [95% CI 0.6–34.3]). Significant associations were found between NMBA use and ASA category (p = 0.046), surgical duration (p = 0.002), use of colloids (p = 0.011), blood products (p = 0.001) and inotropes and/or vasopressors (p < 0.001).Conclusions and clinical relevanceVariables significantly associated with non-survival from canine thoracic surgery at 24 hours include NMBA use and pre-anaesthetic oxygen requirement. Blood product use and increasing surgical duration were associated with non-survival to hospital discharge. The associations may relate to the need for such products in the most complicated cases.     

Intervertebral and intravertebral ratios in Doberman pinscher dogs with cervical spondylomyelopathy

No screening method is currently available to differentiate dogs with and without cervical spondylomyelopathy. Intravertebral and intervertebral ratios are used in horses and can predict cervical vertebral malformation. Intervertebral ratios could be a useful screening method for canine cervical spondylomyelopathy. Our purpose was to compare cervical intervertebral and intravertebral ratios in normal vs. affected Doberman pinschers. Forty dogs were studied, 27 affected and 13 normal. Cervical radiographs were obtained in all dogs. The minimum intra- and intervertebral sagittal diameter ratios were established for each cervical vertebrae and disc space from C(2) to C(7) . Comparisons were made between groups and specific vertebral body and disc levels. The effect of gender, age, and method of measurement (analog or digital radiographs) was also studied. There was no difference in either the intervertebral or intravertebral ratio between normal vs. affected dogs. The ratios decreased progressively along the cervical spine, being smallest at C(6) -C(7) and C(7) , respectively. Age, gender, and method of measurement had a significant influence on both inter- and intravertebral ratios, with smaller ratios seen as dogs aged and in male dogs. Based on our results, inter- or intravertebral ratios have no value to distinguish between clinically normal Doberman pinschers and Doberman pinschers with cervical spondylomyelopathy.     

Pre-weaning morbidity and mortality of llamas and alpacas

Objectives   To describe the morbidity and mortality patterns and identify factors associated with morbidity in pre-weaning llamas and alpacas.
Design   Cross-sectional observational study of 287 crias born on four farms in Ohio, USA
Procedure   Historical data representing all crias born over a 6-year period were obtained from two llama farms and two alpaca farms in Ohio. Multivariable generalised linear mixed effects regression models were used to identify factors associated with morbidity outcomes.
Results   In total, 105 (37%) of the llamas and alpacas had some reported morbidity during the pre-weaning period, and mortality rate was 2.1%. In addition, 51 (18%) of llamas and alpacas experienced morbidity because of infectious disease, and 47 (16%) experienced morbidity during the neonatal period. The three most commonly reported morbidity events were undifferentiated diarrhoea (23%), umbilical hernia (16%) and unspecified infectious disease (15%). Difficult birth was an important risk factor for pre-weaning morbidity in this population.
Conclusions   Camelid veterinarians and their clients can expect that pre-weaning health events are common among crias, although mortality is low. Crias experiencing difficult births may require additional monitoring for health events during the pre-weaning period.     

Prevalence and clinical features of thoracolumbar intervertebral disc‐associated epidural hemorrhage in dogs

BackgroundIntervertebral disc‐associated epidural hemorrhage (EH) in dogs is a poorly understood neurological condition.ObjectiveTo compare the clinical presentation, magnetic resonance imaging (MRI) changes, and clinical outcome of dogs with acute thoracolumbar intervertebral disc herniation (TL‐IVDH) with and without EH.AnimalsOne hundred sixty client‐owned dogs that underwent MRI and hemilaminectomy for acute TL‐IVDH at a private practice in Colorado, including 63 dogs with EH and 97 dogs without EH.MethodsRetrospective review of medical record data from 160 dogs presenting sequentially to a single practice with acute TL‐IVDH that underwent MRI and hemilaminectomy surgery.ResultsSixty‐three of 160 (39%) dogs had confirmed EH. French Bulldogs were significantly overrepresented (23/63; odds ratio [OR]: 4.1; 95% confidence interval [CI]: 1.8‐9.0; P < .001) of the EH cases. Dogs with EH were more likely to present with clinical signs less than 48 hours than were dogs without EH (24‐48 vs 48‐72 hours; OR: 2.4; 95% CI: 1.2‐4.6; P = .02) and were more likely to be nonambulatory on presentation (OR: 2.1; 95% CI: 1.0‐4.1; P = .04). Dogs with EH were more likely to have <50% cross‐sectional spinal cord compression than dogs without EH (OR: 2.3 vs. 0.4; 95% CI: 1.2‐4.4 and 0.2‐0.9, respectively), longer longitudinal spinal cord compression (3 spaces vs 1 space, P < .001), and greater intrinsic spinal cord change (grade 3/severe vs grade 1/mild; P < .001) based on MRI. The location of the intervertebral disc herniation in French Bulldogs with EH was more likely to be thoracolumbar (OR: 10.8; 95% CI: 2.1‐55.7; P = .03).Conclusions and Clinical ImportanceFrench Bulldogs have a high prevalence of intervertebral disc‐associated EH. Dogs with EH have a shorter clinical course and are more likely to be nonambulatory on initial presentation.     

Sex differences in cervical spinal cord and spinal canal development in Thoroughbred horses

Cervical vertebral stenotic myelopathy (CVSM), a common cause of cervical spinal cord compression, is a neurological disease characterized by general proprioceptive ataxia and weakness of hindlimbs that tends to develop in young adult Thoroughbred horses. Although male horses seem to be at increased risk for CVSM, the mechanism for the occurrence of sex differences in the prevalence of CVSM is still poorly understood. Hence, we hypothesized that sex differences in the development of cervical spinal cord and spinal canal would affect the development of CVSM. This study aimed to evaluate sex differences in the development of cervical spinal cord and spinal canal in Thoroughbred horses. A total of 29 Thoroughbred horses underwent computed tomographic myelography. Thereafter, the volumes of cervical spinal cord and spinal canal were calculated. Accordingly, male horses had significantly lager cervical spinal cord volume and cervical spinal cord-to-spinal canal volume ratio than those of female horses (P<0.05). Sex differences in the cervical spinal cord-to-spinal canal volume ratio gradually decreased until around 1,400 days of age. Younger male horses have narrower interspace between the cervical spinal cord and spinal canal than younger female horses, suggesting that an imbalanced cervical spinal cord and spinal canal growth is one of the causes of CVSM.     

Comparison of epidural versus intrathecal anaesthesia in dogs undergoing pelvic limb orthopaedic surgery

ObjectiveTo compare the procedural failure rate (PFR), intraoperative rescue analgesia (iRA) probability and postoperative duration of motor block after epidural and intrathecal anaesthesia in dogs undergoing pelvic limb orthopaedic surgery.Study designProspective, randomized clinical trial.AnimalsNinety-two client-owned dogs.MethodsDogs were assigned randomly to receive either lumbosacral epidural anaesthesia (EA) (bupivacaine 0.5% and morphine 1%) or intrathecal anaesthesia with the same drugs in a hyperbaric solution (HIA). Inaccurate positioning of the needle, assessed by radiographic imaging, and lack of cerebral spinal fluid outflow were considered procedural failures (PFs) of EA and HIA, respectively. Fentanyl (1 μg kg⁻¹ IV) was provided for intraoperative rescue analgesia, when either the heart rate or the mean arterial pressure increased by 30% above the pre-stimulation value. Its use was recorded as a sign of intraoperative analgesic failure. The motor block resolution was evaluated postoperatively. Variables were compared using Fisher's exact test, the Mann–Whitney U test and the Kaplan–Meier ‘survival’ analysis as relevant.ResultsThe PFRs in the EA and HIA groups were 15/47 (32%) and 3/45 (7%), respectively (p = 0.003). Differences in iRA were analysed in 26 and 30 subjects in the EA and HIA groups respectively, using Kaplan–Meier survival analysis. The iRA probability within the first 80 minutes of needle injection (NI) was higher in the EA group (p = 0.045). The incidence of dogs walking within 3 hours of NI was significantly higher in the HIA group (8/20, 40%) than in the EA group (0/17) (p = 0.004).Conclusions and clinical relevanceHIA was found to have lower PF, lower intraoperative analgesic failure and faster motor block resolution. In this study HIA was shown to provide some advantages over EA in dogs undergoing commonly performed pelvic limb orthopaedic surgery in a day-hospital regime.     

A true "triphasic" pattern: thoracolumbar spinal tumor in a young dog

An 8-month-old male Bernese Mountain Dog was referred with a history of hindlimb weakness that progressed to paresis on the right side. An intradural mass was detected in the spinal canal at the level of the 2nd and 3rd lumbar vertebrae. During surgical removal, 2 small fragments of the mass were prepared for cytologic examination by the squash technique. Cytologic examination revealed 3 different cell types: mesenchymal (stromal) cells, epithelial cells, and small undifferentiated hyperchromatic cells. On the basis of location and the triphasic cytologic pattern, a diagnosis of spinal nephroblastoma (thoracolumbar spinal tumor of young dogs) was made; histologic examination of the mass confirmed the cytologic diagnosis. To our knowledge, this is the first report of a triphasic pattern in a cytologic sample; recognizing this pattern is an important aid in reaching a definitive cytologic diagnosis.     

Epidural anesthesia in dogs undergoing hindlimb orthopedic surgery: effects of two injection sites

This prospective clinical trial evaluated the effects of epidural anesthesia (EA) placed at the lumbosacral compared to the L5–L6 junction in dogs undergoing hindlimb orthopedic surgery. In all, 98 dogs were randomly assigned to receive injection at either L7–S1 (LS group) or L5–L6 (LL group) at the same local anesthetic regimen (1 mg/kg bupivacaine 0.5% and 0.1 mg/kg morphine 1%). Fentanyl (1 µg/kg) was the intraoperative rescue analgesia (iRA) administered if mean arterial pressure increased by 30% above pre-stimulation value. Procedural failure, iRA, hypotension, motor block resolution, and postoperative side effects were recorded. There were 7/47 (15%) epidural procedural failures in the LS group and 8/51 (16%) (P=1.00) in the LL group; iRA was administered in 21/40 (52%) LS group dogs and in 13/43 (30%) LL group dogs, respectively (P=0.047). The incidence of hypotension was 10/40 (25%) and 16/43 (37%) in the LS group and the LL group, respectively (P=0.25). Proprioceptive residual deficit at 8 hr after EA was recorded in 3/26 (12%) in group LS dogs and in 13/26 (50%) group LL dogs, respectively (P=0.01). The proprioceptive residual deficit at 24 hr in one dog (LL group) resolved within 36 hr. No episodes of postoperative urinary retention, pruritus or neurological damage were recorded. The L5–L6 EA decreased significantly iRA but delays the proprioceptive recovery time. Further studies are needed to determine whether a lower bupivacaine dose reduces the duration of the residual block retaining the same incidence of iRA.     

Chemical capture of impala (Aepyceros melampus): A review of factors contributing to morbidity and mortality

Objective

To review the factors that contribute to morbidity and mortality of impala undergoing chemical capture, and discuss how they are potentially mitigated.

Computed tomography myelographic findings in dogs with cervical spondylomyelopathy

Computed tomography (CT) myelography is used occasionally in the diagnosis of cervical spondylomyelopathy, but the type of lesion found in large- versus giant-breed dogs using this modality has not been characterized. Our purpose was to report the frequency of compressive lesions in large- and giant-breed dogs with cervical spondylomyelopathy and imaged using CT myelography. Fifty-eight dogs were retrospectively studied, 23 large-breed and 35 giant-breed dogs. Multiple sites of compression were found in 12 large-breed dogs (52.2%) compared to 30 (85.8%) giant-breed dogs. The main site of compression was at C5-6 and C6-7 in both large-breed (91.3%) and giant-breed (72.4%) dogs. The main cause and direction of compression was disc-associated and ventral in 19 (82.6%) of the large-breed dogs while osseous changes were the primary cause of compression in 27 (77.2%) of the giant-breed dogs, with most compressions being lateral (51.4%), followed by dorsolateral (14.2%). Osseous compression was observed at C7-T1 in eight giant-breed dogs (22.8%), and at T1-T2 or T2 only in five dogs (14.3%). Four of 23 large-breed dogs (17.4%), and seven (20%) of 35 giant-breed dogs had spinal cord atrophy. Therefore, giant-breed dogs often have multiple compressions, usually caused by osseous changes causing lateralized compressions. In large-breed dogs most compressions are disc-associated and located ventrally. Considering the number of giant-breed dogs with compressions at C7-T1, T1-2, and T2, it is important to include the cranial thoracic region when imaging dogs suspected of having cervical spondylomyelopathy.     

A single-cohort retrospective analysis of factors associated with morbidity and mortality in 193 anesthetized domestic goats

ObjectiveTo define the morbidity and mortality rates in goats undergoing general anesthesia at a large animal teaching hospital.Study designRetrospective, single-cohort, observational study.AnimalsRecords of 193 client-owned goats.MethodsData were collected from 218 medical records on 193 goats undergoing general anesthesia between January 2017 and December 2021. Demographic data, anesthetic management, recovery period and perianesthetic complications were recorded. Perianesthetic death was defined as anesthesia-related or anesthesia-contributory death occurring within 72 hours after recovery. Records of goats that were euthanized were reviewed to ascertain the cause of euthanasia. Each explanatory variable was individually investigated by univariable penalized maximum likelihood logistic regression, followed by multivariable analysis. Statistical significance was set at p < 0.05.ResultsPerianesthetic mortality was 7.3%, but was 3.4% when considering only goats undergoing elective procedures. Multivariable analysis showed that gastrointestinal surgeries [odds ratio (OR) 19.17, standard error (SE) 12.99, 95% confidence interval (CI) 5.08–72.33; p < 0.01] and requirement for perianesthetic norepinephrine infusion (OR 10.85, SE 8.82, 95% CI 2.21–53.33; p < 0.01) were associated with increased mortality. Maintaining other variables equal, the use of perianesthetic ketamine infusion was associated with decreased mortality (OR 0.09, SE 0.09, 95% CI 0.01–0.73; p = 0.02). Anesthesia-related or anesthesia-contributory complications included hypothermia (52.4%), bradycardia (38.1%), hypotension (35.3%), hypoxemia (14.8%), regurgitation/aspiration (7.3%), azotemia/acute renal failure (4.6%), myopathies/neuropathies (4.1%) and fever of unknown origin (2.7%).Conclusions and clinical relevanceIn this population, gastrointestinal surgeries and the requirement for perianesthetic norepinephrine infusion were associated with increased mortality in goats undergoing general anesthesia, while ketamine infusion may have a protective effect.     

Gastro-oesophageal reflux in large-sized,deep-chested versus small-sized,barrel-chested dogs undergoing spinal surgery in sternal recumbency

Objective

The aim of this study was to investigate whether an increased frequency of gastro-oesophageal reflux (GOR) is more common in large-sized, deep-chested dogs undergoing spinal surgery in sternal recumbency than in small-sized, barrelchested dogs.

Imaging and surgical outcomes of spinal tumors in 18 dogs and one cat

Clinical and magnetic resonance imaging (MRI) findings, histological appearances and surgical outcomes of 18 dogs and one cat with spinal tumors are presented. Medical records of the cases admitted for spinal disorders were reviewed, and cases of spinal tumors that were diagnosed by MRI and confirmed by histological examination were included in this study. T1 weighted, T2 weighted and contrast enhanced T1 weighted images were taken and interpreted to evaluate the spinal tumors. The tumors were diagnosed as: meningioma (n = 6), ependymoma (n = 1), nerve sheath tumor (n = 4), metastatic spinal tumor (n = 3), osteosarcoma (n = 2), osteoma (n = 1), rhabdomyosarcoma (n = 1), and nephroblastoma (n = 1). Thirteen cases underwent surgical operation and the remaining six cases were euthanized at the request of the owners. The neurological status of the surgical cases did not deteriorate, except for one dog that showed ependymoma in the early period after the operation. These results indicate the potential for surgical gross total tumor removal of vertebral tumors to provide better quality of life and surgical collection of histological specimens for definitive diagnosis. For effective case management, dedicated MRI examination is important to accurate evaluation of the spinal tumors, and surgical treatment is useful for extradural and intradural-extramedullary spinal tumors.     

Discal cysts of the cervical spine in two dogs

Discal cysts, which lie directly over intervertebral discs, are rare. Two old dogs with tetraparesis were referred to our facility. In both animals, magnetic resonance imaging revealed intraspinal extradural cystic mass lesions that were dorsal to degenerative intervertebral discs at the C3-C4 level. These lesions had low signal intensity on T1-weighted images, and high signal intensity on T2-weighted images. A ventral slot approach was used to perform surgical decompression, after which the symptoms improved remarkably. Discal cysts should be included in the differential diagnosis of dogs with cervical pain and tetraparesis. One effective treatment for discal cysts is surgical intervention.     

Noninvasive stroke volume variation using electrical velocimetry for predicting fluid responsiveness in dogs undergoing cardiac surgery

Objective

To evaluate the ability of a noninvasive cardiac output monitoring system with electrical velocimetry (EV) for predicting fluid responsiveness in dogs undergoing cardiac surgery.

Electrical velocimetry for noninvasive cardiac output and stroke volume variation measurements in dogs undergoing cardiovascular surgery

Objective

To compare electrical velocimetry (EV) noninvasive measures of cardiac output (CO) and stroke volume variation (SVV) in dogs undergoing cardiovascular surgery with those obtained with the conventional thermodilution technique using a pulmonary artery catheter.

Effect of gonadectomy on pain assessment in dogs undergoing orthopaedic stifle surgery

ObjectiveTo compare pain perception between gonadectomized and intact dogs.Study designBlinded, prospective, cohort study.AnimalsA group of 74 client-owned dogs.MethodsDogs were divided into four groups: group 1—female/neutered (F/N), group 2—female/intact (F/I), group 3—male/neutered (M/N) and group 4—male/intact (M/I). Premedication consisted of intramuscularly administered acepromazine (0.05 mg kg⁻¹) and morphine (0.2 mg kg⁻¹), and subcutaneously administered carprofen (4 mg kg⁻¹). Anaesthesia was induced with propofol (1 mg kg⁻¹ intravenously and supplementary doses to effect) and maintained with isoflurane in 100% oxygen. Intraoperative analgesia was achieved with fentanyl infusion (0.1 μg kg⁻¹ minute⁻¹). Pain assessments [using the University of Melbourne Pain Scale (UMPS) and an algometer at the incision site (IS), parallel to the incision site (NIS), and on the contralateral healthy limb] were performed preoperatively, and at 1, 2, 4, 6, 9 and 20 hours after extubation. The time-standardised area under the curve (AUCst) for measurements was calculated and compared by performing a one-way multivariate analysis of variance (manova). Statistical significance was set at p < 0.05.ResultsPostoperatively, F/N exhibited higher pain than F/I, with estimated marginal means (95% confidence intervals) AUCstIS_Group1 909 (672–1146) versus AUCstIS_Group2 1385 (1094–1675) (p = 0.014), AUCstNIS_Group1 1122 (823–1420) versus AUCstNIS_Group2 1668 (1302–2033) (p = 0.024) and AUCstUMPS_Group1 5.30 (4.58–6.02) versus AUCstUMPS_Group2 4.1 (3.2–5.0) (p = 0.041). Similarly, M/N showed higher pain than M/I with AUCstIS_Group3 686 (384–987) versus AUCstIS_Group4 1107 (871–1345) (p = 0.031) and AUCstNIS_Group3 856 (476–1235) versus AUCstNIS_Group4 1407 (1109–1706) (p = 0.026), and AUCstUMPS_Group3 6.0 (5.1–6.9) versus AUCstUMPS_Group4 4.4 (3.7–5.2) (p = 0.008).Conclusions and clinical relevance:Gonadectomy affects pain sensitivity in dogs undergoing stifle surgery. Neutering status should be taken into consideration when planning individualized anaesthetic/analgesic protocols.     

Agreement between T2 and haste sequences in the evaluation of thoracolumbar intervertebral disc disease in dogs

The purpose of this study was to compare half-Fourier-acquisition single-shot turbo spin-echo (HASTE) and T2-weighted (T2-W) sequences in dogs with thoracolumbar disc extrusion. MRI studies in 60 dogs (767 individual intervertebral disc spaces) were evaluated. Agreement between T2-W and HASTE sequences was assessed for two criteria: presence of an extradural lesion and treatment recommendation. There was moderate agreement between T2-W and HASTE sequences as to presence of an extradural lesion (kappa = 0.575). HASTE was in agreement in 96.1% of the sites where no extradural lesion was identified on T2-W images, but only in 58.1% of the sites where extradural lesions were identified on T2-W images. There was also moderate agreement between T2-W and HASTE sequences as to treatment recommendations (kappa = 0.476). HASTE was in agreement in 98.4% of the sites where a lesion was considered nonsurgical on T2 but only 82.1% of sites a lesion was considered surgical on T2. In 1.0% of sites considered not surgical and in 9.8% of sites considered equivocal based on T2-W images, a surgical lesion was identified on HASTE. Acquisition of a HASTE sequence in addition to conventional sequences may be beneficial in determining the severity of spinal cord compression in some cases when evaluating the canine spine.