Case Report: Microchip Implantation Within the Cervical Spine, a Neurologic Evaluation, and Surgical Correction

Abstract

A 5 mo old male Japanese chin was examined 1 mo following the sudden onset of pelvic limb weakness and ataxia immediately after microchip placement. Neurological examination revealed an ambulatory paraparesis, which was worse on the right side, with additional weakness noted in the right thoracic limb. Lesion localization was C6–T2 spinal cord segments, worse on the right. Radiographic imaging of the cervical spine revealed a microchip at the location of the C7–T1 intervertebral space. Computed tomography revealed a microchip within the spinal canal causing spinal cord compression at the level of the C7–T1 intervertebral disc space. Surgical removal of the microchip was performed, and the patient recovered well. A 6 wk follow-up neurologic examination showed persistent mild ataxia in the pelvic limbs. This case supports previously reported cases of permanent spinal cord damage caused by microchip placement. Surgical removal of the microchip resulted in the improvement of neurologic signs. Although extraction of the microchip did not resolve all neurologic deficits, surgery prevented further migration and possible damage to the spinal cord.

Prevalence, clinical presentation, and etiology of myelopathies in 224 juvenile dogs

“…Publications have either been restricted to specific conditions that are well-recognized in young dogs, such as atlantoaxial instability, fibrocartilaginous embolic myelopathy, vertebral malformations, cervical spondylomyelopathy, spinal arachnoid diverticula (SAD), and spina bifida, [7][8][9][10][11][12] or to isolated case reports including nephroblastoma, microchip implantation, and an inflammatory myofibroblastic tumor. [13][14][15] Other studies have evaluated specific conditions across all age groups, with various findings relating to age, such as an increased likelihood of meningomyelitis of unknown origin in younger dogs, 16 that the age of onset of clinical signs in dogs with spinal arachnoid diverticulum undergoing surgical management (median 18 months) was less than those undergoing medical management (45 months), 17 and that steroid-responsive meningitis-arteritis (with or without signs of myelopathy) was more likely in younger animals (median age 11 months) when compared with meningomyelitis of unknown origin (52 months) or infectious disease (76 months). 18 However, despite extensive literature on specific conditions that can affect younger dogs, the prevalence and underlying causes of juvenile myelopathies in dogs referred for signs of myelopathy remains unknown.…”