ABSTRACT
Introduction/Purpose: MRI features differentiating extrusion from protrusion in thoracolumbar discs have been published, however little specifically evaluates the lumbosacral disc. The high prevalence of degenerative changes in apparently normal animals complicates assessment of this region and features relevant elsewhere in the spine may not apply. The aims of this study were to determine the accuracy of MRI in differentiating IVDE and IVDP at the lumbosacral disc space in dogs and determine which MRI characteristics discriminate between IVDE and IVDP. Method: MRI examinations from dogs with surgically confirmed IVDE or IVDP at the lumbosacral disc space were collected retrospectively (2011-2019). Two radiologists independently recorded a diagnosis of IVDE or IVDP, gave a confidence rating, and evaluated specific MRI features. Univariable statistical analysis was performed to identify which MRI characteristics might help distinguish IVDE from IVDP. Results: 117 dogs with lumbosacral IVDE (n = 16) or IVDP (n = 101) were included. Features associated with IVDE were in concordance with previous studies and included interruption of the dorsal annulus, suspected epidural hemorrhage, dispersed (rather than confined) intervertebral disc herniation on T2W sagittal images, lateralized intervertebral disc herniation and displacement of the cauda equina. Overall diagnostic accuracy was 68.8% and interobserver agreement was fair (κ = 0.37), which is lower than has been reported in thoracolumbar disc herniation, but accuracy increased to 85.3% with substantially improved agreement (κ = 0.87) in "confident" diagnoses. Discussion/Conclusion: MRI characteristics used in differentiating thoracolumbar IVDE and IVDP can be extrapolated to the lumbosacral intervertebral disc space, but diagnostic accuracy in low-field MRI is lower than previously reported in herniations involving the thoracolumbar spine.
ABSTRACT
Persistent socket pain is a condition described in humans after enucleation of the eye. This report aims at describing this condition in dogs. A 10-year-old male-neutered crossbreed was presented to the referral veterinary surgeon for enucleation of the right ocular globe. Anaesthesia and surgery were uneventful although during the postoperative period the dog was reluctant to open the mouth and to be explored by the referral veteterinary surgeon. Despite treatment with meloxicam, paracetamol and tramadol, no improvements were observed. Ten weeks after surgery, the dog was referred to the Dick White referrals for further investigations. Ophthalmic examination was normal, though palpation of the wound triggered an avoidance response. Magnetic resonance imaging showed changes compatible with orbital cellulitis. The area of interest was evaluated with the use of the mechanical Von Frey filaments. A response, characterised by sudden turning of the head and attempts to withdraw it, was evoked with filament 4.93 (8.0 g) during stimulation of the periorbital area. After induction of anaesthesia, an ultrasound-guided injection containing levobupivacaine 0.5% and methylprednisolone was performed within the retrobulbar area. Three hours after recovery from anaesthesia, no discomfort was observed during palpation of the area. Re-evaluation was performed with the Von Frey filaments; no response could be evoked during testing with all 20 filaments (from 2.36 to 6.65) applied on either side of the face. The patient was discharged with a course of gabapentin and, 3 weeks after the intervention, the dog showed no clinical signs of pain. Persistent socket pain is an unpleasant sensation at the level of the enucleated orbit, and it should be regarded as a challenging condition to diagnose and treat. The MRI findings appeared to be essential to select the most appropriate interventional treatment. The injection of local anaesthetic and steroid into the retrobulbar space was useful for both confirming the diagnosis and treating pain by reducing the peripheral signalling and decreasing the residual inflammation.