Traumatic anterolisthesis is rare and results from acute fractures in the neural arch, other than the pars. Dysplastic anterolisthesis (a.k.a. type 1) results from congenital abnormalities of the upper sacral facets or inferior facets of the fifth lumbar vertebra, and accounts for 14% to 21% of all anterolisthesis. Isthmic anterolisthesis (a.k.a. type 2) is caused by a defect in the pars interarticularis but it can also be seen with an elongated pars. Pathologic anterolisthesis (a.k.a. type 5) is caused by either infection or a malignancy. Post-surgical/iatrogenic anterolisthesis (a.k.a. type 6) is caused by complications after surgery. By location
Anterolisthesis location includes which vertebrae are involved, and may also specify which parts of the vertebrae are affected. Isthmic anterolisthesis is where there is a defect in the pars interarticularis. It is the most common form of spondylolisthesis; also called spondylolytic spondylolisthesis, it occurs with a reported prevalence of 5–7 percent in the US population. A slip or fracture of the intravertebral joint is usually acquired between the ages of 6 and 16 years, but remains unnoticed until adulthood. Roughly 90 percent of these isthmic slips are low-grade (less than 50 percent slip) and 10 percent are high-grade (greater than 50 percent slip). It is divided into three subtypes:
A: pars fatigue fracture
B: pars elongation due to multiple healed stress effects
C: pars acute fracture

Severity
Classification by degree of the slippage, as measured as percentage of the width of the vertebral body: Grade I spondylolisthesis accounts for approximately 75% of all cases.
Therefore, if further detail is needed a physician may request advanced imaging. Magnetic Resonance Imaging (MRI)
Magnetic resonance imaging is the preferred advanced imaging technique for evaluation of spondylolisthesis. Preference is due to effectiveness, lack of radiation exposure, and ability to evaluate for soft tissue abnormalities and spinal canal involvement. MRI is limited in its ability to evaluate fractures in great detail, compared to other advanced imaging modalities. Computed Tomography (CT)
Computed tomography can be helpful in evaluating bony vertebral abnormalities, such as fractures. This can be helpful in determining if the fracture is a new, old, and/or progressing fracture. CT use in spondylolisthesis evaluation is controversial due to high radiation exposure. Treatment
Spondylolisthesis patients without symptoms do not need to be treated. Conservative
Non-operative management, also referred to as conservative treatment, is the recommended treatment for spondylolisthesis in most cases with or without neurological symptoms. Most patients with spondylolisthesis respond to conservative treatment. Conservative treatment consists primarily of physical therapy, intermittent bracing, aerobic exercise, pharmacological intervention, and epidural steroid injections. The majority of patients with degenerative spondylolisthesis do not require surgical intervention. Physical therapy can evaluate and address postural and compensatory movement abnormalities. Physical therapy primarily includes spinal flexion and extension exercises with a focus on core stabilization and muscle strengthening. In particular, lumbar spondylolisthesis may benefit from core stabilization exercises focusing on lower abdominal, lumbar muscles, hamstrings, and hip flexors, which may temporarily or permanently improve symptoms and improve general function. Some patients may benefit from bracing in combination with physical therapy.