Imaging of a subcutaneous abscessation in the back of a calf with hindlimb paralysis.

Background: Ultrasonography is not chosen as the common imaging modality to diagnose spinal cord diseases. The present report indicates good diagnostic efficacy of ultrasonography for identifying spinal cord compressed by subcutaneous mass when scanning through the defected vertebral laminae and spinous process.

Case description: A five-month-old female Holstein calf presented with progressive hindlimb paralysis following a surgical resection of a back mass conducted at 21 days of age. The mass was subsequently histopathologically diagnosed as a pulmonary choristoma. Alongside hindlimb paralysis, the calf developed a swollen back at the lumbar region where the mass was removed. This suggested regrowth of the resected mass, causing injury to the underlying spinal cord. Ultrasonography identified the subcutaneous involvement of the capsular mass, which had three anechoic cavities separated by the echogenic septal structures. The spinal cord could be ultrasonographically demonstrated as adjacent to the mass through the defected vertebral laminae and spinous process in the second and third lumbar vertebras. Ultrasound-guided centesis allowed the collection of purulent exudates in which Escherichia coli was isolated. Myelography and subsequent computed tomography (CT) revealed a partial blockage of the intradural flow of contrast media at the levels of the second and third lumbar vertebras, diagnosed as spina bifida on the CT images. When applying ultrasonography to the spinal cord within a saline pool soon after the subcutaneous abscess was successfully resected, the spinal cord was characterized by the interrupted and partly extended hyperechogenic line of the central canal within the echogenic parenchyma. The echotexture of the spinal cord showed damage due to compression from the subcutaneous abscess. The animal had a sub-optimal postoperative outcome, including limited improvement of the neurological signs.

Conclusion: In the present case, combining ultrasonography, radiography (myelography), and CT was very effective for diagnosing spina bifida, with the subcutaneous abscess inducing spinal cord compression. Additionally, using intraoperative ultrasonographic scanning to evaluate the degree of spinal cord damage can contribute to predicting the postoperative outcome.