Isthmic spondylolisthesis’s may also become symptomatic in adults, most typically when people are in their thirties and forties. The most common reason for low back pain in this situation is that the disc will start to wear out. Without a posterior tether connecting the facet joints, the disc space is forced to withstand shear forces. Normally the facet joints in the back of the spine protect the disc from shear as they act to limit the shear force. When there is a pars interarticularis fracture the facet joints cannot limit shear. Discs work well as a shock absorber but they are susceptible to being damaged if they have to resist shear. The associated cumulative stress leads the disc to breakdown and eventually become painful.

Also, as the discs break down, there is less room for the exiting nerve root (the L5 nerve root) and the patient can develop leg pain (radiculopathy, or sciatica). It is common for the leg pain to be related to walking or standing as in these positions the foramen (the opening where the nerve exits the spine) is closed down. When sitting the foramen is larger and eliminates the pressure on the nerve. However, the converse may also be true, as in the sitting position the disc is loaded three times more than when standing, and the loaded disc can bulge into the foramen causing leg pain.

Non-surgical treatment for adult patients with a spondylolisthesis is similar to that for patients with back pain from other conditions and may include one or a combination of:

• NSAID’s (e.g. ibuprofen, COX-2 inhibitors)
• Mild pain medications, TENS unit, or braces
• Oral steroids
• Physical therapy (stretching the hamstrings twice daily in order to alleviate stress on the low back)
• Manual manipulation (e.g. chiropractic manipulation)
• Injections for low back pain or epidural injections for symptoms of sciatica.

If pain is more severe, injections can be useful. Epidural injections can help decrease inflammation in the area near the spinal nerve(s). The pars fracture itself can be injected with lidocaine and steroids for a diagnostic study. If the patient’s pain is relieved after a lidocaine injection it can be assumed that the pars fracture is the source of the patient’s pain. The steroid can be useful to reduce inflammation in the pars interarticularis, helping to relieve the pain and allow the patient to progress with non-surgical treatment.

In most cases non-surgical treatment is successful in relieving the patient’s pain, but if not surgery can be considered. Spinal fusion surgery for spondylolisthesis is generally quite effective, but because it is a large procedure with a lot of recovery, it usually is not considered until a patient has failed to find pain relief with at least six months of vigorous non-surgical treatment. Because a lumbar fusion inherently alters normal spinal mechanics and may lead an acceleration of degenerative changes, surgery must be a “last resort” and reserved for the older individual.

A posterior fusion with pedicle screw instrumentation is generally considered the gold standard form of lumbar spinal fusion. The surgeon may also recommend a spinal fusion done from the front of the spine (an ALIF) at the same time. The type of spinal fusion that is recommended by a surgeon is based largely on a surgeon’s preference and experience, as well as the patient’s clinical situation.