A group of Japanese orthopedic surgeons have been studying young athletes who experience low back pain that goes down the leg. The leg pain is referred to as radiculopathy. It means there is pressure on a spinal nerve root in the lumbar spine. This type of presentation is rare in young athletes. After collecting data on 10 such cases, the authors provide a report on what’s going on to cause these symptoms.
Using X-rays and CT scans, the surgeons were able to identify the main problem as lumbar spondylolysis. Lumbar, of course, refers to the vertebrae in the low back or lumbar spine. Spondylolysis is a medical term to describe a stress fracture of a supporting column of bone called the pars interarticularis. The most common place for this type of fracture is at the last lumbar level (L5).
Once the fracture occurs, the body sets up a healing response. Bone fills in around the fracture site forming a bone callus or osteophyte. This lump of bone isn’t always smooth and round. Sometimes it can have jagged edges. And there isn’t a lot of extra room in this area of the spine. If the bone extends over into the area where the nerve root leaves the spine to go down the leg, pressure on the nerve from the osteophyte can case leg pain (radiculopathy). There can be other symptoms such as altered sensation in the leg and/or foot (e.g., numbness, pins and needles).
Most adults who develop back and leg pain associated with lumbar spondylolysis do so because of the osteophyte nerve compression. But in this younger group, there wasn’t any evidence of osteophyte nerve compression, yet radiculopathy still occurred. The authors reasoned that there must be other reasons for this symptom.
Sure enough, when they did further imaging studies with MRIs, they found a cyst in one patient and a herniated disc in two others. The remaining seven patients in the study group had a hematoma (pocket of pooled blood) and edema (swelling) in the area of the fracture site. It appeared that these two responses to the fracture were irritating the nerve root closest to the fracture site.
The patients were treated and followed over time to see what the final results would be. The patient with a cyst ended up having surgery to remove it. The patients with disc problems were treated successfully with conservative (nonoperative) care. And the remaining patients with hematomas and edema were also treated conservatively. Conservative care consisted of wearing a brace for at least a month and stopping all sports and physical activities.
Everyone was followed with repeat MRIs, which showed a gradual healing response at the fracture site. As a result of seeing the various causes of the radiculopathy, the patients were divided into two separate groups. The group with cyst or disc-related problems were labeled as having nonspondylolytic radiculopathies. For the patients with disc problems, stress on the disc between the fractured vertebra and the vertebra above or below it resulted in disc degeneration, protrusion, and eventually herniation. Because the cause of the radiculopathy isn’t the fracture site itself but something else caused by the fracture (cyst or disc), this type of radiculopathy gets the nonspondylolytic radiculopathy designation.
The rest of the patients were labeled as having spondylolytic radiculopathies. Their symptoms were a direct result of changes at the fracture site (edema and hematoma). The changes were not because of jagged bone edges pressing on the nearby nerves as is often seen in adults with this problem.
Instead, these young patients with spondylolytic radiculopathies were in the early stages of spondylolysis when the body was still responding to the acute injury. The natural history (what happens over time) for these patients is that the body heals itself over a period of months. The fracture heals, the swelling goes down, and the body absorbs the hematoma. These changes take place over a period of six to seven months. For the patients in this study, surgery was not required for the problem to resolve itself. We call this a self-limiting condition.
In summary, radiculopathy (leg pain) can occur in young athletes who have been diagnosed with lumbar spondylolysis but the condition is rare. This is the first study to show that radiculopathies can be spondylolytic (those caused directly by the fracture site) or nonspondylolytic. Spondylolytic radiculopathies don’t always occur because of jagged bone edges pressing on the nearby nerve. There can be other causes of nerve impingement such as the hematoma and edema observed in the early stages of healing. Nonspondylolytic causes of radiculopathy occur less often and can be accounted for by cyst formation or disc degeneration — indirect biomechanical effects of the spondylolysis defect.