There is a lucent lesion in the vertebra (right image), nicely targetted via a transpedicular approach with CT guidance.

The procedure took under half an hour, with a small amount of discomfort to the patient (aided by a generous dose of local anaesthetic), when in the past, this would have required open surgery. The patient was on his feet and shopping within 2 hours. Modern medicine!

There is osteoarthrosis of the interspinous joint secondary to dessication and loss of intervertebral disc space (Baastrup's disease). There will also be narrowing of the exit foramina bilaterally, resulting in back pain and radicular pain. Spinal claudication (pain after walking a certain distance) is present.

This is condition may be delayed or treated with placement of interspinous devices.

The location of the spinous processes under the skin allows for the implantation of interspinous process spacers with minimal operative intervention and unwanted after effects of surgery. The interspinous process devices are designed to distract (open) the foramina, where the nerve roots traverse. These devices may also reduce the axial load on the intervertebral disc.

Below are images of 4 interspinous devices (clockwise from upper left quadrant: the coflex, DIAM, Wallis and X-Stop.

Patient presents with back pain. No other history provided on request form. Sagittal T2 and TIRM sequences demonstrated. All looks like degeneration, right?

2 weeks later, she's back. What's happened?

There's now spondylodiskitis: increased T2 signal within the L4 and L5 vertebrae, and the L4/5 disk. Worse, it's associated with paraspinal soft tissue swelling and enhancement with anterior epidural abscess formation. Note: the bladder is grossly distended (and if you were like me, I wouldn't be lying in the cold MRI tunnel with a bladder THAT full)- which suggests that there is bladder neuropathy.

So, be careful, it's not always simple degeneration. Infection has to start at some place, and early infection is not ruled out on MRI.

What are the radiological signs for this condition?

The spine radiographs reveal fusion of the sacroiliac joints. The enthesophytes are not well demonstrated radiographically, unlike on CT. In fact, there's also ankylosis of the facet joints, and the interspinous ligaments- giving rise to the dagger sign. There is also increased density of the vertebral corners (shiny corners). (You'd also look out for endplate erosions secondary to inflammatory discitis- the Anderssen lesion).

 

All keywords for the diagnosis of ankylosing spondylitis.

 

But wait! Look at the CT image (2nd row, 1st image)- there's a chalk fracture. This is the dangerous thing about ank spond: the entire spine is fused as a brittle single column, and a fracture easily propogates through (like a Chance fracture). The cord is therefore at risk, and an MRI will be useful to evaluate for cord injury.

Check out these images of the lumbar spine!

T2-weighted 3D SPACE scan of the lumbar spine. The images were obtained with textured volume rendering and windowed to exclude bone. The result is a 3D myelogram effect, showing narrowing at L4/5 due to combination of spondylolisthesis and disc bulge. The source images were acquired in sagittal plane at 0.9 x 0.9 x 0.9 mm (isotropic).