Computed Tomography-Guided Fine Needle Biopsies of Vertebral and Paravertebral Lesions in Small Animals

Abstract

Fine needle biopsy (FNB) is an effective, minimally invasive and inexpensive diagnostic technique. Under computed tomography (CT)-guidance, lesions that have a difficult approach can be sampled to reach a diagnosis. The aim of this study is to describe the use of CT-guidance to obtain FNB from vertebral and paravertebral lesions in small animals. Ten dogs and one ferret that had undergone CT-guided FNB of vertebral and paravertebral lesions and had a cytological or a histological diagnosis were included in this retrospective study. The FNB samples were taken in four cases from the vertebra, in two cases from the intervertebral disc and in five cases from the intervertebral foramen. Two infectious and nine neoplastic lesions were diagnosed. The percentage of successful FNB was 91%. The percentage of samples with a cytological diagnosis was 80%. The percentage of complications was 9%. Limitations were the small number of animals in the study, the lacking complementary percutaneous biopsies for comparison, the lacking final histological diagnoses in some cases and the intervention of multiple operators. Computed tomography-guided FNB is a useful and safe technique for the diagnosis of vertebral and paravertebral lesions in small animals. However, a degree of expertise is important.

Keywords: computed tomographic-guidance; fine needle biopsy; small animals; vertebral.

Figure 1

Case 2, 6-year-old Bullterrier with lumbosacral (LS) discospondylitis. (a) Sagittal multiplanar reconstruction (MPR) of the LS region in a bone window. There is moderate narrowing of the intervertebral disk space (IVDS) and severe osteolysis of the caudal L7 and cranial S1 endplates, with moderate sclerosis and marked spondylosis deformans; (b) Transverse MPR of the LS IVDS in a bone window. There is evidence of a spinal needle in the intervertebral space, introduced in a left ventrolateral approach.

Figure 2

Case 3, 9-year-old Bodeguero andaluz with a L5–L6 right sided suspected peripheral nerve sheath tumor. (a) Transverse and (b) dorsal multiplanar reconstruction (MPR) of the lumbar spine (L5–L6) in a soft tissue window. There is an extramedullary intradural right-sided mass extending through the vertebral canal at the level of L5 and through the intervertebral foramen (IVF) at L5–L6. Note the muscle atrophy on the right epaxial muscles; (c) Transverse MPR at the level of the L5–L6 IVF in a bone window. There is evidence of a spinal needle in the mass in the IVF, introduced in a right dorsolateral approach.

Figure 3

Case 6, 13-year-old Weimaraner with a polyostotic aggressive bone lesion (L3 and L4) associated to a hypaxial soft tissue mass consistent with a sarcoma. (a) Transverse and (b) sagittal multiplanar reconstruction (MPR) of the lumbar spine in a bone window. There is a large soft tissue mass in the right hypaxial muscles infiltrating the vertebral body and transverse processes of L3 and L4 and invading the retroperitoneal space. There is a pathological fracture of L3 vertebral body with vertebral compression; (c) Transverse MPR at the level of L3 in a bone window. There is evidence of a spinal needle in the hypaxial mass and the lytic L3 vertebral body, introduced in a right dorsolateral approach.

Figure 4

Degenerate neutrophils with intracellular bacilli consistent with suppurative septic discospondylitis (case 2). Modified-wright stain, 100×.

Figure 5

Mesenchymal cells with mild to moderate atypia consistent with sarcoma (case 6). Modified-wright stain, 40×.