MRI findings in 133 dogs with repeated disc surgery problems

Abstract

BACKGROUND: Recurrence of neurological signs following surgery for intervertebral disc herniation (IVDH) is reported, yet many cases lack MRI-confirmed diagnosis. This study describes the MRI and clinical findings in dogs presenting with recurrence of neurological signs following surgical treatment of IVDH. METHODS: Medical records of dogs that underwent decompressive surgery for IVDH followed by a subsequent MRI within 12 months were retrospectively reviewed. RESULTS: One hundred and thirty-three dogs were identified, all of which initially presented with intervertebral disc extrusion (IVDE). Of these, 109 (81.9%) had a recurrent IVDE, and 24 (18.1%) had an alternative diagnosis that included haemorrhage (n = 10), infection (n = 4), soft tissue encroachment (n = 3), myelomalacia (n = 3) or other (n = 4). Same-site IVDE recurrence or alternative diagnoses were significantly more likely to present within 10 days postoperatively. Thirty-nine percent of dogs presenting with 'early recurrence' had an alternative diagnosis. Type of surgery, fenestration, neurological grade or IVDE site was not significantly associated with the subsequent MRI diagnosis. LIMITATIONS: Limitations include the retrospective study design, the exclusion of conservatively managed recurrences, the variable length of follow-up and differences in the clinicians' surgical experience. CONCLUSION: The most common cause for the recurrence of neurological signs following decompressive spinal surgery was IVDE. Just over one-third of dogs presenting with early recurrence had an alternative diagnosis.