Spondylolisthesis

Spondylolisthesis refers to the displacement of one vertebrae in relation to the one below. The displacement can be forward (anterior) or backwards (posterior) displacement. Forward slippage of one vertebra on another is referred to as anterolisthesis, while backward slippage is referred to as retrolisthesis. As the pain is felt in, and exaccerbated by extending the back, it is quite common in dancers and acrobats.

The condition is graded according to the degree of slippage of one segment upon the other.

• Grade I is anything up to 25% of the vertebrae 
• Grade II is between 26%-50%
• Grade III is between 51%-75%
• Grade IV is between 76% and 100%
• Grade V, or spondyloptosis occurs when the vertebra has completely fallen off the next vertebra.

The only way that the vertebrae can slip forward is if there is a defect in part of the bone of the vertebrae. There are several reasons as to why this may occur:

• Congenital – the defect in the vertebrae occurs at birth and often in the facet region.
• Repeated trauma– This type of Spondylolisthesis can be caused by repetitive trauma and is more common in athletes exposed to hyperextension motions including those seen in gymnastics and dance. The defect is in a portion of the vertebra called the pars interarticularis. This is the reaason why we strongly discourage strong hyperextended movements of the spine in young dancers.
• Degenerative Spondylolisthesis – occurs due to arthritic changes in the joints of the vertebrae due to cartilage degeneration. This is more common in older patients.
• Traumatic Spondylolisthesis – is due to direct trauma or injury to the vertebrae. his can be caused by a fracture of the pedicle, lamina or facet joints that allows the front portion of the vertebra to slip forward with respect to the back portion of the vertebra.
• Pathologic Spondylolisthesis – is caused by a defect in the bone caused by abnormal bone, such as from a tumor.

Diagnosis

Splonylolisthesis will usually have pain with extension, such as going into a back bend, or an arabesque. The pain is usually quite low, where the spine connect to the sacrum, and will often be difficult to settle with rest or heat. In extreme cases, where the spinal cord is affected, they may experience numbness or tingling in both feet or legs.

The condition can be easily identified using a plain film X ray. An X-ray taken from the side will show if one of the vertebrae has slipped forward compared to the neighboring vertebrae.

The X-ray will also show the magnitude of the slippage, which is usually measured by the percentage of the vertebrae that has slipped forward, for example, a Grade I is under 25% of the vertebral body, or 1/4 of the vertebrae.

Treatment

If the situation is more severe, surgery may be needed to fuse the slipped vertebrae. This may be needed if you have:

• Severe pain that does not get better with treatment
• A severe slip of a spine bone
• Weakness of muscles in one or both of your leg

There is a chance of nerve injury with such surgery. However, the results can be very successful. You will need a consultation with a spinal surgeon for this.