Surgical removal of a microchip from a puppy’s spinal canal

Abstract

A 1.6 kg, six-week-old Tibetan Terrier was admitted with a 12-hours history of acute onset of progressive tetraparesis following insertion of a microchip to the dorsal cervical region. Neurological examination indicated a lesion to the Ce(1) to Ce(5) spinal cord segments. Radiographic examination confirmed the intra-spinal location of a microchip foreign body at the level of the second cervical vertebra. Microchip removal was achieved following dorsal hemi-laminectomy; significant intra-operative haemorrhage was encountered. The puppy was ambulatory at day seven. Follow-up telephone interview 18 months postoperatively confirmed that the patient had made a good recovery although it had a mild residual right- sided torticollis.

Intra-parenchymal brainstem haemorrhage secondary to iatrogenic needle injury after a parenteral injection in a cat

“…CNS iatrogenic needle injuries have previously been reported following CSF collection attempts from the CMC and caudal lumbar site in dogs, and following microchip implantation in dogs and cats. 5–8 A self-inflicted needle-stick injury and spinal cord infarction has been described in a human being. 9 In the present case, we suspect that the needle entered the CNS through the atlanto-occipital junction.…”

Migrating sewing needle in the cervical vertebral canal in a dog

“…Clinical signs associated with foreign bodies in the vertebral canal can be caused by direct injury to the spinal cord by the foreign material, or related to haemorrhage, infection or granuloma formation secondary to the intruding material (Johnston and Summers 1971, Brockman and Trout 1991, Pratt and others 1999, Rayward 2002, Leskovar and others 2003, Dennis and others 2005, Granger and others 2007, Mateo and others 2007, Platt and others 2007, Hicks and Bagley 2008, Smith and Fitzpatrick 2009, Joslyn and others 2010, Schneider and others 2010, Sutton and others 2010, Potanas and others 2011, Tanaka and others 2012, Whitty and others 2013). Needles are very thin and of an inert material, so direct injury of the spinal cord should be theoretically minimal.…”

“…Some of the foreign bodies found in people's vertebral canals have been pellets, glass fragments, acupuncture needles or epidural catheters that have broken and migrated along the epidural space (Abumi and others 1996, Patrick 2005, Williams and others 2009, Akcakaya and others 2012, Thompson and Aasheim 2012, Keel and others 2013). In veterinary medicine, direct traumatic implantation of microchips in the vertebral canal has been reported in three dogs and one cat (Platt and others 2007, Hicks and Bagley 2008, Smith and Fitzpatrick 2009, Joslyn and others 2010). In three of these cases, acute neurological signs and pain were found (Platt and others 2007, Hicks and Bagley 2008, Smith and Fitzpatrick 2009) and while the third case developed clinical signs three years after microchip placement, it was suspected the implant had been placed within the C5‐C6 interarcuate ligament and epaxial musculature, possibly in contact with the dorsal surface of the cranial left lamina of C6 (Joslyn and others 2010).…”

“…In veterinary medicine, direct traumatic implantation of microchips in the vertebral canal has been reported in three dogs and one cat (Platt and others 2007, Hicks and Bagley 2008, Smith and Fitzpatrick 2009, Joslyn and others 2010). In three of these cases, acute neurological signs and pain were found (Platt and others 2007, Hicks and Bagley 2008, Smith and Fitzpatrick 2009) and while the third case developed clinical signs three years after microchip placement, it was suspected the implant had been placed within the C5‐C6 interarcuate ligament and epaxial musculature, possibly in contact with the dorsal surface of the cranial left lamina of C6 (Joslyn and others 2010). Plant material that has migrated from different levels is a common migrating foreign body found in companion animals (Brennan and Ihrke 1983, Frendin and others 1999, Jones and Ober 2007, Schultz and Zwingenberger 2008, Sutton and others 2010, Potanas and others 2011, Whitty and others 2013).…”

“…Hyperaesthesia is the most common clinical finding associated with foreign bodies in the nervous system (Rayward 2002, Granger and others 2007, Platt and others 2007, Hicks and Bagley 2008, Smith and Fitzpatrick 2009, Schneider and others 2010, Tanaka and others 2012). Neurological signs may vary from pain to paralysis, depending on many factors, such as size or location of the foreign body, tissue injury or chronicity.…”