Incidence, risk factors, and outcomes for early postoperative seizures in dogs with rostrotentorial brain tumors after intracranial surgery.

BACKGROUND: Seizures in the early postoperative period after intracranial surgery may affect outcome in dogs. OBJECTIVES: To determine the incidence of early postoperative seizures (EPS) in dogs with brain tumors, identify specific risk factors for EPS, and determine if EPS affects outcome. ANIMALS: Eighty-eight dogs that underwent 125 intracranial surgeries for diagnosis and treatment of rostrotentorial brain tumors. METHODS: Retrospective cohort study. All patients with a diagnosis of rostrotentorial brain tumor from 2006 to 2020 were included. Early postoperative seizures were diagnosed by observation of seizure activity within 14 days of neurosurgery. Previously diagnosed structural epilepsy, perioperative anticonvulsant drug (ACD) use, magnetic resonance imaging (MRI), and tumor characteristics were evaluated. Outcome measures included neurologic and nonneurologic complications, duration of hospitalization, and survival to discharge. RESULTS: Dogs with rostrotentorial brain tumors had EPS after 16/125 (12.8%) neurosurgical procedures (95% confidence interval [CI], 7%-19%). Presence of previous structural epilepsy was not associated with EPS risk (P = 1). Perioperative ACD use also was not associated with EPS (P = .06). Dogs with EPS had longer hospitalization (P < .001), were more likely to have neurologic complications postsurgery (P = .01), and were less likely to survive to discharge (P = .01). CONCLUSIONS AND CLINICAL IMPORTANCE: It is difficult to predict which dogs are at risk of EPS because the presence of previous structural epilepsy and the use of perioperative ACDs was not associated with EPS. However, seizures in the early postoperative period are clinically important because affected dogs had prolonged hospitalization, more neurologic complications, and decreased short-term survival.

Microendoscopic Dorsal Laminectomy for Multi-Level Cervical Intervertebral Disc Protrusions in Dogs.

The objective of this study was to evaluate the feasibility and clinical outcomes of microendoscopic dorsal laminectomy for multi-level cervical intervertebral disc protrusions in dogs. Eight client-owned dogs diagnosed with multi-level cervical intervertebral disc protrusions using computed tomography (CT) and magnetic resonance imaging (MRI) were included in this retrospective case series. Microendoscopic dorsal laminectomies (MEL) were performed with an integrated endoscopic system to the cranial and caudal vertebrae of the affected intervertebral joints. Pre- and post-operative neurological status, operation time, intra-operative complications, and postoperative complications were reviewed. Post-operative CT images were obtained to measure the dimensions of laminectomy and compared to those of planned laminectomy. Full endoscopic procedures were feasible in 7 dogs (87.5%) and the laminectomy dimensions were in agreement with pre-operative planning. In all dogs, major intra- and postoperative complications did not occur. Conversion to open surgery was required in one case. Short-term postoperative clinical deterioration was found in two dogs. Long-term clinical outcomes were good and comparable to those reported in previous studies of open dorsal laminectomies. MEL is a promising minimally invasive approach to multi-level cervical dorsal laminectomy for intervertebral disc protrusions. This technique may improve postoperative discomfort compared to the open approach. Further studies are needed to directly compare outcomes between these two approaches.

Microendoscopic Mini-Hemilaminectomy and Discectomy in Acute Thoracolumbar Disc Extrusion Dogs: A Pilot Study.

The objective of this study was to evaluate the clinical outcomes and complications of a microendoscopic laminectomy and discectomy (MED) for acute thoracolumbar intervertebral disc extrusions in dogs. Eleven client-owned dogs with acute thoracolumbar intervertebral disc extrusions were included in this retrospective case-series. Dogs were diagnosed with acute thoracolumbar intervertebral disc extrusions using computed tomography (CT) and magnetic resonance imaging (MRI). MED was performed with an integrated endoscopic system to the affected intervertebral disc. Surgery time, intra-operative complications, causes of conversion to microscopic surgery if necessary, post-operative complications, and neurological status on presentation at discharge, as well as any further evaluations in hospital, and long-term concerns via owner contact, were recorded. Post-operative CT images were obtained to compare the extent of laminectomy performed to the planned region of laminectomy. The fully endoscopic procedure was completed in eight dogs without major complications. Three cases were converted to an open surgery due to difficulty removing extruded disc material and controlling hemorrhage. The clinical outcome was good in all cases and equivalent to previously reported prognoses after open surgery. MED is an effective and safe alternative to conventional open procedures in dogs with acute thoracolumbar intervertebral disc extrusion.

Determination of surgical exposure obtained with integrated endoscopic thoracolumbar hemilaminectomy in large-breed cadaveric dogs.

OBJECTIVE: To define boundaries of minimally invasive integrated endoscopic hemilaminectomy at 4 sites in the canine thoracolumbar spine. STUDY DESIGN: Experimental, randomized cadaveric study. ANIMALS: Six cadaver dogs that had been humanely euthanized for reasons unrelated to this study. METHODS: Hemilaminectomy was performed with an integrated endoscopic system at T11-12, T12-13, L1-2, and L2-3, 1 at each site, on the left or right side of each dog. Each site was randomly assigned either a 19-mm or a 23-mm cannula. The entire procedure, including soft tissue dissection, was performed through the cannula. Afterward, spines were imaged by computed tomography (CT) to measure the cranial and caudal extent of the hemilaminectomy from the center of the disc space. RESULTS: The mean ± SD cranial extent of the hemilaminectomy was 4.5 ± 1.4 mm for the 19-mm cannula and 5.6 ± 1.4 mm for the 23-mm cannulas (P = .0757). The caudal extent of the hemilaminectomy was 9.5 ± 2.2 mm for the 19-mm cannula and 10.3 ± 1.6 mm for the 23-mm cannula (P = .206). The mean length of the hemilaminectomy was 13.0 ± 1.5 mm for the 19-mm cannula and 15.0 ± 2.1 mm for the 23-mm cannula (P = .022). CONCLUSION: Integrated endoscopic systems were reliably used to access the spinal canal within the range of the above measurements relative to the disc space as identified by CT or magnetic resonance imaging. CLINICAL SIGNIFICANCE: Integrated endoscopy can be considered as an option in dogs with thoracolumbar disc extrusions or other pathology measuring within the parameters defined by this study. Access may be possible beyond the dimensions defined in this study with probing and repositioning.