Spinal cord trauma in a cat caused by ingestion of a splinter

Abstract

A 5-month-old male Abyssinian presented with right hemiplegia. Cervical radiographs, haematology and serum biochemistry were normal. A foreign body was identified on computed tomography (CT) and magnetic resonance imaging (MRI). Removal of the foreign body was carried out via a dorsal approach between the occipital bone and the C1 vertebral body using intra-operative CT. No complications were encountered. Thirty days after surgery, the cat was ambulatory.

Case Report

A 5-month-old male Abyssinian was referred to the Horie Animal Medical Center for evaluation of right hemiplegia. Seven days earlier, the owner had noticed the cat lying in the kitchen, after which the cat developed right-sided paralysis. The limbs on the left side were normal. The cat could not walk.

Cervical radiographs, haematology and serum biochemistry were performed by the referring veterinarian (Inada Animal Hospital) and did not reveal any abnormalities. Although once-daily 5 mg/kg enrofloxacin (Baytril; Bayer, Osaka, Japan) and 2 mg/kg prednisolone (Predonine; Shionogi & Co, Osaka, Japan) were administered by the referring veterinarian, improvement was not seen.

On initial examination at the Horie Animal Medical Center, mild neck pain was detected. On neurological examination, right hemiplegia was observed with the right fore- and rear-limbs showing upper motor neuron (UMN) signs. Spinal reflexes were increased with normal deep pain nociception. On the same day, for purposes of computed tomography (CT) evaluation, general anaesthesia was induced with ketamine (Ketamine; Fujita Pharmaceutical, Tokyo, Japan) and maintained with isoflurane and oxygen. Helical CT (Asteion4; Toshiba Medical Systems, Tochigi, Japan) of the cervical spine (2 mm sections) was performed, revealing a defined lesion in the spinal canal between the occipital bone and atlas (C1) vertebral body. The edge of the lesion projected ventrally from the space between the caudal occipital bone and the rostral aspect of C1. The lesion was localised to the right (Figure 1 a, b). While the cat remained under sedation, magnetic resonance imaging (MRI) of the cervical spinal cord was performed using a 0.2 T permanent magnet (VetMR; Esaote SpA, Genova, Italy). T2- and T1-weighted images were acquired in the transverse planes; T1-weighted images were acquired following administration of gadolinium-DTPA (Omniscan; Daiichi Sankyo, Tokyo, Japan). This examination revealed an isointense lesion on the T2-weighted images and hypointense on the T1-weighted images. It was not enhanced with contrast. The margin of the lesion was hyperintense on the coronal contrast-enhanced T1-weighted images (Figure 1 c–f). CT and MRI revealed an intradural, extramedullary foreign body causing spinal cord compression between the occipital bone and C1 vertebral body on the right.

Figure 1

Sagittal (A) and transverse (B) CT images without contrast. Transverse T2-weighted MRI (C), T1-weighted MRI (D), post-contrast T1-weighted MRI (E), and coronal contrast-enhanced T1-weighted MRI (F). The lesion (arrowhead) entered the spinal canal between the occipital bone and the C1 vertebral body (A) and was localised to the right (B). The lesion was isointense on the T2-weighted images (C), hypointense on the T1-weighted images (D) and not enhanced on the contrast-enhanced T1-weighted images (E). The margin of the lesion was hyperintense (arrow) on the coronal contrast-enhanced T1-weighted images (F)

While still under anaesthesia, the foreign body was removed via a dorsal approach in the CT remodeled surgery room. After making an incision through the dorsal skin, subcutaneous tissue and muscles that extended from the occipital bone to the cranial part of the C2 vertebral body, the cisterna magna was exposed. A thin needle was inserted around the dura mater. Intra-operative CT was used to determine the distance between the needle and the foreign body. The needle was used as a marker for the incision through the dura mater; an incision through the dura mater was made revealing purulent exudate. During aspiration of this material, a chopstick splinter was found (Figure 2). The spinal cord appeared grossly normal. The surgical field was flushed with copious amounts of sterile saline and closed. The purulent exudate was cultured aerobically at a research laboratory (Osaka Kessei Research Laboratories, Osaka, Japan) growing a Staphylococcus species that was sensitive to cephalexin, ampicillin, gentamycin and clindamycin.

Figure 2

A chopstick splinter was removed from the spinal canal

Postoperatively, clindamycin was administered subcutaneously (Dalacin; Pfizer, Tokyo, Japan; 5 mg/kg, q12h) for 2 days, followed by oral clindamycin therapy for 4 weeks. Methylprednisolone succinate (Decacort; Sawai Pharmaceutical, Osaka, Japan, 30 mg/kg, q24h) was administered for 1 day.

Voluntary motor activity returned in the right forelimb and hindlimb on the third day after surgery. By 7 days postoperatively, the cat was able to walk with assistance. Thirty days after surgery, the cat was ambulatory. At this time, neurological examination was normal.

CT and MRI have been used in recent years to diagnose feline spinal cord diseases. ¹ Many types of feline spinal cord diseases have been reported — the most prevalent being inflammatory/infectious diseases (accounting for 32% of spinal cord diseases in cats), neoplastic diseases (27%) and spinal cord trauma (14%). ² There are several case reports of spinal cord trauma, intervertebral disc disease ³ and incorrect microchip placement. ⁴

Foreign body ingestion is frequently reported in cats, mainly affecting the nasopharynx, ⁵ oropharynx ⁶ and oesophagus. ⁷ In this case, we believe that the foreign body was introduced directly through the oropharynx because of the ventral projection from the space between the caudal occipital bone and the rostral aspect of C1, and because no puncture wounds were found in the skin of the neck. Although several spinal cord traumas have been reported, there have been no previous reports of spinal cord trauma caused by foreign body ingestion.

In humans, intra-operative CT provides precise localisation of intracranial targets and targeted structures. ⁸ In dogs and cats, intra-operative CT has only been reported in stereotactic brain biopsy. ⁹ Intra-operative CT is less common in cats than it is in humans. In this case, intra-operative CT was undertaken in the CT remodeled surgery room. Removal of the foreign body was undertaken on the CT table. As soon as the intra-operative CT was completed, the CT operator removed the CT table from the gantry so the surgeons could complete the foreign body removal. Intra-operative CT provided precise localisation of the foreign body and assisted the surgery. This is the first report of intra-operative CT used to augment spinal surgery in a cat.