Cervical spinal cord compression may affect anesthetic recovery quality and seizure incidence in horses after myelography

Objective: To compare anesthetic recovery quality and seizure incidence after cervical myelography in horses with or without cervical spinal cord compression. Methods: Anesthesia and medical records from January 2017 to December 2022 of horses anesthetized for myelography were retrieved. Patients with incomplete records, equine protozoal myeloencephalitis diagnosis, or an anesthetic protocol outside an established standard were excluded. Demographic analysis, ataxia score, and anesthetic management variables were recorded in an observational retrospective fashion. Each variable was compared between groups, and multivariable regression models were constructed to evaluate the correlation of each factor with 2 outcomes: recovery quality and seizure incidence. Results: Of 270 cases, 194 were included in the analysis, with 44 cases in the compression group and 150 in the noncompression group. An association between an increase in body weight and worse recovery quality was found (score of 25 [relative risk ratio, 1.04; 95% CI, 1.00 to 1.08]). Compression may increase the risk of a worse recovery (relative risk ratio, 8.89; 95% CI, 1.84 to 42.97). Horses with compressive lesions showed a higher, but statistically insignificant, incidence of seizures in the late recovery period. Conclusions: Heavier horses have a greater risk of worse anesthetic recovery after myelography, independent of age, breed, or ataxia status. Horses with cervical compression potentially present a higher seizure risk within the first 24 hours after myelography than those without compression but not in the immediate recovery. Clinical Relevance: Heavier horses require more attention to the recovery phase. Horses with cervical compression may need close monitoring for seizures during the first 24 hours after myelography.