Lumbosacral foraminal ratios and areas using MRI in medium-sized dogs.

OBJECTIVE

To examine conventional magnetic resonance imaging planes of the lumbosacral foramina to obtain objective measurements of foraminal size in medium-sized (20-28 kg) normal dogs.

METHOD: Ten canine cadavers were evaluated using magnetic resonance imaging in neutral, flexed and extended position. Foraminal ratios, areas and lumbosacral angles were calculated and their relationship to body weight was evaluated.

RESULTS

Foraminal ratios were found to be independent of body weight in medium sized dogs (p >0.42). Foraminal areas were dependent on body weight (p <0.05). Flexion and extension were shown to significantly change both the foraminal ratio and area.

CLINICAL SIGNIFICANCE: Lumbosacral foraminal stenosis is common in working dogs. Foraminal ratios were evaluated in medium-sized dogs and were found to be independent of body weight, which may provide objective evaluation of surgical decompression techniques if calculated pre- and post-surgery. Foraminal areas were not independent of body weight.