Use of intraoperative ultrasonography in canine spinal cord lesions

The purpose of this retrospective study was to describe the intraoperative appearance of various spinal cord conditions, and to investigate how intraoperative ultrasonography assisted in modification of surgical and postoperative treatment plans. Intraoperative ultrasonography (B-mode, and power Doppler mode) was used in 25 dogs undergoing spinal surgery. The neurologic conditions included cervical spondylomyelopathy, intervertebral disc (IVD) protrusion, IVD extrusion, spinal tumors, nerve sheath mass, granulomatous myelitis, and discospondylitis. All of these diagnoses were supported by histopathologic and/or cytologic evaluation. It was possible to visualize the spinal cord and the abnormal spinal tissue in all of the patients. Power Doppler imaging allowed assessment of the spinal cord microcirculation, and assisted in judgment of the degree of decompression. Ultrasound imaging directly impacted the surgical and the medical treatment plans in four patients. Owing to the intraoperative imaging, two hemilaminectomies were extended cranially and caudally, and additional disc spaces were fenestrated, one hemilaminectomy site was extended dorsally to retrieve the disc material from the opposite side, and one intramedullary cervical spinal cord lesion was discovered, aspirated, and consequently diagnosed as granulomatous inflammation, which altered the long-term medication protocol in that dog. This study suggests that intraoperative sonographic spinal cord imaging is a useful and viable technique.