6 Types of Spondylolisthesis

Also known as a slipped vertebra, spondylolisthesis occurs when a vertebra slides forward over the vertebra beneath it. In fact, in Greek, the root word -listhesis means “to slip.”

A dislocated vertebra can occur for any number of reasons. However, the lumbar spine (or lower back) runs the highest risk of developing this type of injury. This is because your lower back bears the brunt of the torso’s weight, and hence, sustains a significant amount of wear and tear.

Unfortunately, spondylolisthesis can be dangerous. When a vertebra slips out of alignment, it makes the entire spine unstable. This can lead to serious consequences, like a spinal deformity or spinal cord compression. You may need emergency surgery to repair and realign the spine…

…Or, you may exhibit no symptoms whatsoever. The range of symptoms with spondylolisthesis is so diverse that doctors have created several classification systems to sort out the differences.

One of these methods—The Meyerding Grading System—ranks the severity of the slippage. The scale indicates the percent of forward slip over the vertebral body beneath the dislocated vertebra. The scale works as follows:

• Grade I: 1 – 25 % forward slip
• Grade II:26 – 50 % forward slip
• Grade III:51 – 75 % forward slip
• Grade IV:76 – 99% forward slip
• Grade V: Indicates that the vertebra has slipped entirely off of the spinal column, a very severe condition known as spondyloptosis

Other Classification Methods

However, you will also discover that doctors find it useful to classify spondylolisthesis according to the Wiltse classification system. In contrast, this method sorts the disorder into different types based upon the cause. You will find that many forms of spondylolisthesis result from structural weakness on the backside of the spine.

So, without further ado, these are the six major types of spondylolisthesis according to Wiltse:

• Dysplastic Spondylolisthesis: Also known as congenital spondylolisthesis, this form of slipped vertebra results from a defect that is present at birth. This defect can weaken the facet joints, the points of articulation where two vertebrae meet to create spinal movement. When this point of connection is vulnerable, everyday movements, like bending or twisting, can knock the vertebrae out of alignment.
• Isthmic Spondylolisthesis: This condition occurs when a stress fracture develops in the pars interarticularis, a narrow strip of bone that connects our vertebrae at the facet joints. Children normally develop this type of fracture between the ages of 5 – 7. However, symptoms are not usually noticed until adulthood, when the facet joints continue to degenerate and spondylolisthesis results.
• Degenerative Spondylolisthesis: If your facet joints degenerate from age, then this form of spondylolisthesis can result. In fact, it is a fairly common consequence of osteoarthritis. This disorder can lead to spinal stenosis, or a narrowing of the spinal canal that houses your spinal cord. When this occurs, symptoms such as muscular weakness in the hamstrings, can arise.
• Traumatic Spondylolisthesis: Spinal fractures from sudden injuries like vehicular accidents or falls can instantly knock the spine out of alignment. When this occurs, doctors refer to this type of slipped vertebra as traumatic. This distinguishes this type of dislocated vertebra from isthmic spondylolisthesis, which can occur naturally during the course of childhood.
• Pathologic Spondylolisthesis: This condition results from an underlying disease, like Paget’s Disease, spinal tumors, or osteomyelitis, etc. Each of these disorders can weaken the points of attachment that hold the vertebrae together. This can result in a sudden injury to the spine, like a slipped vertebra.
• Iatrogenic Spondylolisthesis: This occurs when a surgical error weakens the structural integrity of the spine, leading to spondylolisthesis. For example, during a laminectomy, a spine surgeon removes the lamina, or bony backside of the spine, to relieve pressure on spinal nerve roots. Often, your surgeon will then need to insert hardware to maintain the stability of the spine. If this crucial last step is missed, then you can develop postsurgical complications, like spondylolisthesis.

Preventing Spondylolisthesis

Although it is impossible to prevent certain types of spondylolisthesis, you can take measures to protect your back from injury. If possible, attempt to follow these guidelines:

• Maintain a healthy BMI. Excess weight in the abdominal region places extreme stress on the lower back, making spondylolisthesis more likely. In addition, obesity can lead to host of other problems that encourage facet joint deterioration, like osteoarthritis.
• Eat “spine healthy” foods. In addition to laying off of the junk, try to eat foods that support “good” spine health. Make sure to consume plenty of calcium and vitamin D in your diet – both of these vitamins and minerals contribute to good bone health.
• Exercise several days each week. Strengthen the muscles that support your back by completing weight-bearing exercises each week. Make sure to consult with a professional (a personal trainer, physical therapist, etc.) to identify safe activities and stretches for your back.
• Use proper lifting techniques. Always lift heavy objects from your knees instead of your back. Avoid hyperextending your spine as you straighten out your legs.
• Avoid tobacco: Studies show that smoking compounds back pain and slows down the healing the process. Limit your tobacco consumption.
• Practice “good” sleep hygiene. Get at least 8 hours of sleep each evening. Buy a mattress that is firm but not hard. Although this seems like basic common sense, receiving proper lumbar support at night goes a long way toward preventing injuries during the daytime.

And, when all else fails, seek the professional guidance of a board-certified spine specialist. Dr. Daveed Frazier, Harvard-trained orthopedic surgeon, has earned over 20 years of experience in resolving spine disorders, like spondylolisthesis. You can review the case study section of our blog to learn how Dr. Frazier uses minimally invasive surgical techniques to treat spondylolisthesis!