Presumed pituitary apoplexy in 26 dogs: Clinical findings, treatments, and outcomes.

BACKGROUND: Pituitary apoplexy refers to hemorrhage or infarction within the pituitary gland resulting in acute neurological abnormalities. This condition is poorly described in dogs. OBJECTIVES: To document presenting complaints, examination findings, endocrinopathies, magnetic resonance imaging (MRI), treatments, and outcomes of dogs with pituitary apoplexy. ANIMALS: Twenty-six client-owned dogs with acute onset of neurological dysfunction. METHODS: Retrospective case series. Dogs were diagnosed with pituitary apoplexy if MRI or histopathology documented an intrasellar or suprasellar mass with evidence of hemorrhage or infarction in conjunction with acute neurological dysfunction. Clinical information was obtained from medical records and imaging reports. RESULTS: Common presenting complaints included altered mentation (16/26, 62%) and gastrointestinal dysfunction (14/26, 54%). Gait or posture changes (22/26, 85%), mentation changes (18/26, 69%), cranial neuropathies (17/26, 65%), cervical or head hyperpathia (12/26, 46%), and hyperthermia (8/26, 31%) were the most frequent exam findings. Ten dogs (38%) lacked evidence of an endocrinopathy before presentation. Common MRI findings included T1-weighted hypo- to isointensity of the hemorrhagic lesion (21/25, 84%), peripheral enhancement of the pituitary mass lesion (15/25, 60%), brain herniation (14/25, 56%), and obstructive hydrocephalus (13/25, 52%). Fifteen dogs (58%) survived to hospital discharge. Seven of these dogs received medical management alone (median survival 143 days; range, 7-641 days) and 8 received medications and radiation therapy (median survival 973 days; range, 41-1719 days). CONCLUSIONS AND CLINICAL IMPORTANCE: Dogs with pituitary apoplexy present with a variety of acute signs of neurological disease and inconsistent endocrine dysfunction. Dogs that survive to discharge can have a favorable outcome.

Vascular endothelial growth factor concentrations in the cerebrospinal fluid of dogs with neoplastic or inflammatory central nervous system disorders.

BACKGROUND: Vascular endothelial growth factor (VEGF) is a key molecular driver of angiogenesis and vascular permeability and is expressed by a wide variety of neoplasms. Although blood VEGF concentrations have been quantified in intracranial tumors of dogs, cerebrospinal fluid (CSF) VEGF concentration might be a more sensitive biomarker of disease. OBJECTIVE: Concentrations of VEGF in CSF are higher in dogs with central nervous system (CNS) neoplasia compared to those with meningoencephalomyelitis and other neurologic disorders. ANIMALS: One hundred and twenty-six client-owned dogs presented to a veterinary teaching hospital. METHODS: Case-control study. Cerebrospinal fluid was archived from dogs diagnosed with CNS neoplasia and meningoencephalomyelitis. Control dogs had other neurological disorders or diseases outside of the CNS. A commercially available kit was used to determine VEGF concentrations. RESULTS: Detectable CSF VEGF concentrations were present in 49/63 (77.8%) neoplastic samples, 22/24 (91.7%) inflammatory samples, and 8/39 (20.5%) control samples. The VEGF concentrations were significantly different between groups (P < .0001), and multiple comparison testing showed that both neoplastic and inflammatory groups had significantly higher concentrations than did controls (P < .05), but did not differ from each other. Gliomas and choroid plexus tumors had significantly higher VEGF concentrations than did the control group (P < .05). CONCLUSIONS AND CLINICAL IMPORTANCE: Cerebrospinal fluid VEGF concentrations may serve as a marker of neoplastic and inflammatory CNS disorders relative to other conditions.

Outcomes and prognostic indicators in 59 paraplegic medium to large breed dogs with extensive epidural hemorrhage secondary to thoracolumbar disc extrusion.

OBJECTIVE: To evaluate outcomes and prognostic factors after decompressive hemilaminectomy in paraplegic medium to large breed dogs with extensive epidural hemorrhage (DEEH) and thoracolumbar intervertebral disc extrusion (TL-IVDE). STUDY DESIGN: Retrospective, cohort, descriptive study. ANIMALS: Fifty-nine client-owned dogs. METHODS: Medical records and advanced imaging were reviewed for paraplegic dogs with DEEH. Ambulatory status 6 months after surgery and postoperative complications were recorded. Multiple logistic regression models were constructed to explore prognostic factors. RESULTS: Records of 22 dogs with and 37 dogs without pelvic limb pain perception at presentation were included. Median age of dogs was 5 years (interquartile range, 4-7), and mean weight was 26.9 kg (SD, ±9.71). Labradors and Labrador mixes were most common (17/59 [28.8%]). Recovery of ambulation occurred in 17 of 22 (77.3%) dogs with and in 14 of 37 (37.8%) dogs without pain perception prior to surgery. Progressive myelomalacia was recorded in three of 59 (5.1%) dogs, one with pain perception and two without pain perception at presentation. Postoperative complications (14/59 [23.7%]) were common. Factors independently associated with outcome included clinical severity (odds ratio [OR] 0.179, P = .005), number of vertebrae with signal interruption in half Fourier single-shot turbo spin-echo sequences (HASTEi; OR, 0.738; P = .035), and ratio of vertebral sites decompressed to HASTEi (OR, 53.79; P = .03). CONCLUSION: Paraplegic medium to large breed dogs with DEEH have a less favorable outcome after surgical decompression than paraplegic dogs with TL-IVDE. CLINICAL SIGNIFICANCE: Dogs with DEEH can have severe postoperative complications. Loss of pain perception and increased HASTEi are associated with a poor outcome, while more extensive decompression improves outcome.

Cerebrospinal fluid lactate concentrations in dogs with seizure disorders.

BACKGROUND: Cerebrospinal fluid (CSF) lactate concentrations increase after seizure activity in many human patients independent of the underlying disease process. The effect of seizure activity on CSF lactate concentration in dogs is unknown. HYPOTHESIS/OBJECTIVES: Cerebrospinal fluid lactate concentration is unaffected by seizure activity in dogs and is more dependent on the underlying disease process causing the seizures. ANIMALS: One-hundred eighteen client-owned dogs with seizure disorders. METHODS: Case series. Cerebrospinal fluid lactate concentration was determined using a commercially available lactate monitor. Seizure semiology, time from last seizure to CSF collection, number of seizures within the 72 hours preceding CSF collection, and clinical diagnosis were recorded. RESULTS: Dogs with focal seizures had higher CSF lactate concentrations than did those with generalized seizures (P = .03). No differences in lactate concentrations were found among dogs with single seizures, cluster seizures or status epilepticus (P = .12), among dogs with CSF collection at different time points after the last seizure activity (P = .39) or among dogs having different numbers of seizures within the 72 hours preceding CSF collection (P = .42). A significant difference (P = .001) was found in CSF lactate concentrations among diagnostic groups, and dogs with inflammatory and neoplastic disease had higher concentrations than did dogs with idiopathic or unknown epilepsy. CONCLUSIONS AND CLINICAL IMPORTANCE: Cerebrospinal fluid lactate concentration is minimally affected by seizure activity in dogs and increased concentrations are more likely associated with the underlying disease process.

Association between anesthesia duration and outcome in dogs with surgically treated acute severe spinal cord injury caused by thoracolumbar intervertebral disk herniation.

BACKGROUND: Retrospective research recently identified a possible relationship between duration of surgery and outcome in severely affected dogs treated surgically for acute thoracolumbar intervertebral disk herniation (TL-IVDH). HYPOTHESIS: That increased duration of surgery is associated with poorer outcome in dogs with absent pain perception treated surgically for TL-IVDH. ANIMALS: Two hundred ninety-seven paraplegic dogs with absent pain perception surgically treated for acute TL-IVDH. METHODS: Retrospective cohort study. Medical records of 5 institutions were reviewed. Inclusion criteria were paraplegia with absence of pain perception, surgical treatment of TL-IVDH, and 1-year postoperative outcome (ambulatory: yes or no). Canine data, outcome, and surgery and total anesthesia duration were retrieved. RESULTS: In this study, 183/297 (61.6%) dogs were ambulatory within 1 year, 114 (38.4%) dogs failed to recover, including 74 dogs (24.9%) euthanized because of progressive myelomalacia. Median anesthesia duration in dogs that regained ambulation within 1 year of surgery (4.0 hours, interquartile range [IQR] 3.2-5.1) was significantly shorter than those that did not (4.5 hours, IQR 3.7-5.6, P = .01). Multivariable logistic regression demonstrated a significant negative association between both duration of surgery and total anesthesia time and ambulation at 1 year when controlling for body weight and number of disk spaces operated on. CONCLUSIONS AND CLINICAL IMPORTANCE: Findings support a negative association between increased duration of anesthesia and outcome in this group of dogs. However, the retrospective nature of the data does not imply a causal relationship.

Risk factors associated with progressive myelomalacia in dogs with complete sensorimotor loss following intervertebral disc extrusion: a retrospective case-control study.

BACKGROUND: Progressive myelomalacia (PMM) is a usually fatal complication of acute intervertebral disc extrusion (IVDE) in dogs but its risk factors are poorly understood. The objective of this retrospective case-control study was to identify risk factors for PMM by comparing dogs with complete sensorimotor loss following IVDE that did and did not develop the disease after surgery. We also investigated whether any risk factors for PMM influenced return of ambulation. Medical records of client-owned dogs with paraplegia and loss of pain perception that underwent surgery for IVDE from 1998 to 2016, were reviewed. Dogs were categorized as PMM yes or no based on clinical progression or histopathology. Walking outcome at 6 months was established. Signalment, onset and duration of signs (categorized), steroids, non-steroidal anti-inflammatory drugs (yes or no), site of IVDE (lumbar intumescence or thoracolumbar) and longitudinal extent of IVDE were retrieved and their associations with PMM and walking outcome were examined using logistic regression. RESULTS: One hundred and ninety seven dogs were included, 45 with and 152 without PMM. A 6-month-outcome was available in 178 dogs (all 45 PMM dogs and 133 control dogs); 86 recovered walking (all in the control group). Disc extrusions at the lumbar intumescence were associated with PMM (p = 0.01, OR: 3.02, CI: 1.3-7.2). Surgery performed more than 12 h after loss of ambulation was associated with PMM (OR = 3.4; CI = 1.1-10.5, p = 0.03 for 12-24 h and OR = 4.6; CI = 1.3-16.6, p = 0.02 for the > 24 h categories when compared with the ≤12 h category). Treatment with corticosteroids was negatively associated with PMM (OR: 3.1; CI: 1.3-7.6, p = 0.01). The only variable to affect walking outcome was longitudinal extent of IVDE (OR = 2.6; CI = 1.3-5.3, p = 0.006). CONCLUSION: Dogs with lumbar intumescence IVDE are at increased risk of PMM. Timing of surgery and corticosteroid use warrant further investigations. PMM and recovery of walking are influenced by different factors.

Presence of cerebrospinal fluid antibodies associated with autoimmune encephalitis of humans in dogs with neurologic disease.

BACKGROUND: Presumed autoimmune diseases affecting the central nervous system (CNS) of dogs are common. In people, antibodies against neuronal cell surface antigens that are associated with a wide variety of neurological syndromes have been identified. The presence of cerebrospinal fluid (CSF) autoantibodies that target neuronal cell surface proteins has not been reported in dogs with neurologic disorders. OBJECTIVES: Autoantibodies to neuronal cell surface antigens can be found in the CSF of dogs with inflammatory CNS disease. Our aim was to determine whether 6 neuronal cell surface autoantibodies were present in the CSF of dogs diagnosed with inflammatory and noninflammatory CNS disease. ANIMALS: Client-owned dogs with CNS disease and complete diagnostic evaluation including magnetic resonance imaging and CSF analysis were included. One healthy dog was included as a negative control. METHODS: Cerebrospinal fluid was tested for 6 antigenic targets with a commercially available indirect immunofluorescence assay test kit. RESULTS: There were 32 dogs with neurological disease, 19 diagnosed with inflammatory disease (encephalitis and meningitis), 10 with noninflammatory disease (neoplasia, intervertebral disk disease, degenerative myelopathy, and epilepsy), 2 with no diagnosis, and 1 with neoplasia and meningoencephalitis. Anti-N-methyl-d-aspartate receptor 1 (NMDAR1) antibodies were detected in 3 dogs (3/32; 9.38%). All 3 dogs responded to treatment of meningoencephalomyelitis of unknown etiology (MUE). CONCLUSIONS AND CLINICAL IMPORTANCE: Further evaluation of the prevalence and clinical relevance of CSF and serum antibodies to neuronal cell surface antigens is warranted. Defining antigenic targets associated with encephalitis in dogs might allow diagnostic categorization of MUE antemortem.

Time course and prognostic value of serum GFAP, pNFH, and S100ß concentrations in dogs with complete spinal cord injury because of intervertebral disc extrusion.

BACKGROUND: A noninvasive biomarker is needed to predict recovery from severe spinal cord injury (SCI) because of thoracolumbar intervertebral disc extrusion (TL-IVDE). Proteins released from neural and glial cells can be detected in the blood and show promise as prognostic tools, but their concentration is influenced by time after injury. HYPOTHESIS/OBJECTIVES: Serum concentrations of glial fibrillary acidic protein (GFAP), phosphorylated neurofilament heavy chain (pNFH), and S100ß will follow different time courses; measurement of combinations of these proteins will predict outcome. ANIMALS: Thirty-one dogs with TL-IVDE causing paralysis with no pain perception. METHODS: Prospective study. Serum samples were taken at presentation and intervals over 56 days and banked at -80°C. Glial fibrillary acidic protein, pNFH, and S100ß concentrations were measured using ELISA tests and plotted against time from onset of nonambulatory status. Outcome was established at 6 months. The association between biomarker concentration and outcome was examined using logistic regression, receiver operator characteristics curve analysis, and model development. RESULTS: Thirty-one dogs participated, 3/31 (10%) developed progressive myelomalacia and 19/31 (62%) recovered ambulation. Glial fibrillary acidic protein and S100ß concentrations rose for the first 1 to 3 days, and were undetectable by 14 and 28 days, respectively. Phosphorylated neurofilament heavy chain concentrations peaked at 14 days and were detectable at 56 days. Glial fibrillary acidic protein concentrations in the first 72 hours after onset of nonambulatory status predicted recovery with an accuracy of 76.7%-89% depending on sample timing. CONCLUSIONS AND CLINICAL IMPORTANCE: Serum GFAP concentrations can be used to predict outcome in clinically complete SCI. A rapid inexpensive bedside test is needed.

A randomized, blinded, prospective clinical trial of postoperative rehabilitation in dogs after surgical decompression of acute thoracolumbar intervertebral disc herniation.

BACKGROUND: Experimental evidence shows benefit of rehabilitation after spinal cord injury (SCI) but there are limited objective data on the effect of rehabilitation on recovery of dogs after surgery for acute thoracolumbar intervertebral disc herniations (TL-IVDH). OBJECTIVE: Compare the effect of basic and intensive post-operative rehabilitation programs on recovery of locomotion in dogs with acute TL-IVDH in a randomized, blinded, prospective clinical trial. ANIMALS: Thirty non-ambulatory paraparetic or paraplegic (with pain perception) dogs after decompressive surgery for TL-IVDH. METHODS: Blinded, prospective clinical trial. Dogs were randomized (1:1) to a basic or intensive 14-day in-house rehabilitation protocol. Fourteen-day open field gait score (OFS) and coordination (regulatory index, RI) were primary outcomes. Secondary measures of gait, post-operative pain, and weight were compared at 14 and 42 days. RESULTS: Of 50 dogs assessed, 32 met inclusion criteria and 30 completed the protocol. There were no adverse events associated with rehabilitation. Median time to walking was 7.5 (2 - 37) days. Mean change in OFS by day 14 was 6.13 (confidence intervals: 4.88, 7.39, basic) versus 5.73 (4.94, 6.53, intensive) representing a treatment effect of -0.4 (-1.82, 1.02) which was not significant, P=.57. RI on day 14 was 55.13 (36.88, 73.38, basic) versus 51.65 (30.98, 72.33, intensive), a non-significant treatment effect of -3.47 (-29.81, 22.87), P = .79. There were no differences in secondary outcomes between groups. CONCLUSIONS: Early postoperative rehabilitation after surgery for TL-IVDH is safe but doesn't improve rate or level of recovery in dogs with incomplete SCI.

The Effect of Electromagnetic Fields on Post-Operative Pain and Locomotor Recovery in Dogs with Acute, Severe Thoracolumbar Intervertebral Disc Extrusion: A Randomized Placebo-Controlled, Prospective Clinical Trial.

Spinal cord injury (SCI) attributed to acute intervertebral disc extrusions (IVDEs) is common in dogs and is treated by surgical decompression. Dogs with sensorimotor complete injuries have an incomplete recovery. Pulsed electromagnetic fields (PEMFs) reduce post-operative pain through anti-inflammatory effects and there is growing evidence for neuroprotective effects. This randomized, controlled clinical trial evaluated the effect of PEMF on post-operative pain and neurological recovery in dogs with surgically treated sensorimotor complete SCI attributed to acute IVDE. Sixteen dogs with surgically treated complete thoracolumbar SCI were randomized to receive PEMF (15 min every 2 h for 2 weeks then twice-daily for 4 weeks) or placebo starting immediately after diagnosis. The primary outcome was gait score at 2 weeks. Secondary measures of gait, pain perception, and proprioceptive function were evaluated at 2 and 6 weeks. Plasma glial fibrillary acidic protein (GFAP) concentration was measured as an SCI biomarker. Post-operative pain was quantified by measuring mechanical sensory thresholds (MSTs) at control and surgical sites. There was no significant difference in demographics or GFAP concentration between the two groups at trial entry. There was no difference in primary outcome or in secondary measures of gait, but proprioceptive placing was significantly better at 6 weeks and GFAP concentrations were significantly lower at 2 weeks in the PEMF group. MSTs were significantly higher in the PEMF-treated group. We conclude that PEMF reduced incision-associated pain in dogs post-surgery for IVDE and may reduce extent of SCI and enhance proprioceptive placing. Larger clinical trials are warranted.

Eosinophilic meningomyelitis associated with T-cell lymphoma in a cat.

A 12-year-old cat was presented for evaluation of progressive tetraparesis. Magnetic resonance imaging of the cervical spine demonstrated T2-hyperintensity, and contrast enhancement within the C4-C7 spinal cord, with marked meningeal contrast enhancement and segmental nerve root thickening. Lumbar cerebrospinal fluid contained 407 total nucleated cells/µL, with 99% eosinophils. The cat transiently improved with prednisolone, clindamycin, and ivermectin therapy, but subsequently worsened and was euthanized. Necropsy revealed an asymmetric infiltration predominantly of the white matter, meninges, and nerve roots of the C4-C6 spinal cord segments by an unencapsulated, poorly demarcated neoplasm composed of atypical lymphocytes admixed with eosinophils, causing perivascular hemorrhage and lytic necrosis. The neoplastic cells were immunoreactive for CD3, ultimately confirming T-cell lymphoma.

The cutaneous trunci muscle reflex: a predictor of recovery in dogs with acute thoracolumbar myelopathies caused by intervertebral disc extrusions.

OBJECTIVE: To determine whether changes in the cutaneous trunci muscle (CTM) reflex are an early predictor of outcome in dogs with severe acute thoracolumbar intervertebral disc extrusion (IVDE). STUDY DESIGN: Multicenter prospective cohort study. ANIMALS: Dogs (n = 36) with acute IVDE causing paraplegia, loss of nociception in pelvic limbs and tail, and an abnormal CTM reflex postoperatively. METHODS: The caudal border of the CTM reflex was established 24 hours after surgery and at discharge, and was reported as moving cranially, caudally, or staying static. Dogs were re-evaluated at 12-20 weeks and at 7-36 months postoperatively. Outcome was classified as improved or unimproved, successful or unsuccessful, and ascending myelomalacia or not, and compared with early movement of the CTM reflex by construction of contingency tables and performing a Fisher's exact test. RESULTS: By discharge (mean, 4.7 days; SD = 2.10), CTM reflex progression was caudal in 19 dogs, static in 11, and cranial in 6. Five of 6 dogs with cranial movement developed ascending myelomalacia (P < .0001). Seventeen of 19 dogs with caudal movement showed an improvement by 12-20 weeks (P = .0046) and none developed ascending myelomalacia (P = .0013). CONCLUSIONS: Postoperative changes of the caudal border of the CTM reflex are an early indicator of outcome in dogs with severe acute IVDE. Cranial movement of the CTM reflex is significantly associated with the development of ascending myelomalacia. Caudal movement is significantly associated with improvement, but not associated with a long-term successful outcome.

Vertebral stabilization using positively threaded profile pins and polymethylmethacrylate, with or without laminectomy, for spinal canal stenosis and vertebral instability caused by congenital thoracic vertebral anomalies.

OBJECTIVE: To describe diagnostic findings, surgical technique, and outcome in dogs with thoracic spinal canal stenosis and vertebral instability secondary to congenital vertebral anomalies. STUDY DESIGN: Retrospective clinical study. ANIMALS: Dogs (n=9) with thoracic spinal canal stenosis. METHODS: Medical records (1995-1996; 2000-2006) of 9 dogs with a myelographic diagnosis of spinal canal stenosis and/or vertebral instability secondary to congenital vertebral anomaly that were surgically managed by vertebral stabilization with or without laminectomy were reviewed. Data on pre- and postoperative neurologic status, diagnostic findings, surgical techniques, and outcomes were retrieved. Follow-up evaluations were performed at 1, 2, and 6 months. Long-term outcome was assessed by means of clinical examination or owner telephone interviews. RESULTS: Spinal cord compression was confirmed by myelography, and in 2 dogs, dynamic compression by stress myelography. Eight dogs regained the ability to ambulate postoperatively. One dog with a partial recovery regained voluntary movement but did not become ambulatory. CONCLUSIONS: Spinal cord injury secondary to congenital vertebral anomaly may have a good outcome when treated by vertebral stabilization with or without laminectomy. Adequate stabilization of the vertebrae and improved neurologic outcome were achieved in most dogs. CLINICAL RELEVANCE: Vertebral stabilization using positively threaded profile pins and polymethylmethacrylate with or without laminectomy is an effective treatment for spinal canal stenosis and vertebral instability secondary to congenital thoracic vertebral anomalies.

Clinicopathological abnormalities and treatment response in 24 dogs seroreactive to Bartonella vinsonii (berkhoffii) antigens.

Bartonella vinsonii (B. vinsonii) subspecies berkhoffii is a recently recognized cause of endocarditis, myocarditis, and granulomatous disease in dogs. In an effort to elucidate other potential disease manifestations, the case records of 24 dogs that were seroreactive to B. vinsonii (berkhoffii) antigens were studied retrospectively. Diagnoses included immune-mediated hemolytic anemia, neutrophilic or granulomatous meningoencephalitis, neutrophilic polyarthritis, cutaneous vasculitis, and uveitis. Repeated B. vinsonii (berkhoffii) antibody titers became negative after treatment. This study indicates that a diverse spectrum of disease manifestations and clinicopathological abnormalities can be detected in dogs that are seroreactive to B. vinsonii (berkhoffii) antigens.

Spinal arachnoid cysts in 17 dogs.

The medical records of 17 dogs diagnosed with spinal arachnoid cysts at North Carolina State University Veterinary Teaching Hospital were retrospectively examined to identify trends in signalment, history, neurological status, treatment, and short- and long-term prognosis. The typical case was that of a nonpainful, progressive ataxia frequently characterized by hypermetria and incontinence. Cysts typically occurred in the dorsal subarachnoid space at the first to third cervical vertebrae of young, large-breed dogs or the caudal thoracic vertebrae of older, small-breed dogs. Although 14 of 15 dogs treated surgically did well in the short term, long-term successful outcomes were achieved in only eight of the 12 dogs that were followed for >1 year. Significant predictors of good, long-term outcome were not identified; however, factors associated with a trend toward a good outcome included <3 years of age, <4 months' duration of clinical signs, and marsupialization as the surgical technique.

Use of vagal nerve stimulation as a treatment for refractory epilepsy in dogs.

OBJECTIVE: To evaluate safety and efficacy of vagal nerve stimulation in dogs with refractory epilepsy. DESIGN: Placebo-controlled, double-masked, crossover study. ANIMALS: 10 dogs with poorly controlled seizures. PROCEDURE: A programmable pacemaker-like device designed to deliver intermittent stimulation to the left cervical trunk of the vagus was surgically implanted in each dog. Dogs were assigned randomly to two 13-week test periods, 1 with nerve stimulation and 1 without nerve stimulation. Owners recorded data on seizure frequency, duration, and intensity, as well as adverse effects. RESULTS: No significant difference in seizure frequency, duration, or severity was detected between overall 13-week treatment and control periods. During the final 4 weeks of the treatment period, a significant decrease in mean seizure frequency (34.4%) was detected, compared with the control period. Complications included transient bradycardia, asystole, and apnea during intraoperative device testing, and seroma formation, subcutaneous migration of the generator, and transient Horner's syndrome during the 14-day period between surgery and suture removal. No adverse effects of stimulation were detected, and most owners were satisfied with the treatment. CONCLUSIONS AND CLINICAL RELEVANCE: Vagal nerve stimulation is a potentially safe approach to seizure control that appears to be efficacious in certain dogs and should be considered a possible treatment option when antiepileptic medications are ineffective.