Are all levels of disc herniation the same? Can they be treated in the same way and still get the same results? The authors of this study look to see if disc herniation at an upper lumbar level responds the same to treatment as a disc herniation at the lower lumbar/sacral level.
They used data already collected from a large study called the Spine Patient Outcomes Research Trial (SPORT). They compared patients with three levels of disc herniation: L2-L3, L4-L5, and L5-S1. And they compared the results of two forms of treatment: nonoperative care and surgical treatment to remove the disc (discectomy).
The patients in each group were similar in terms of gender and body size (weight and height). There were more men than women in all three groups. And age varied from group to group with younger adults in the lower level herniations group and older adults in the upper lumbar group.
Symptoms were slightly different based on the level of herniation. Upper lumbar disc problems were more likely to cause back and anterior (front of the) thigh pain.
Lower lumbar disc herniation is usually accompanied by pain down the back of the leg called sciatica.
Leg symptoms were less severe with upper level herniations. Neurologic testing of reflexes and sensory or motor changes differ from upper lumbar to lower lumbar spine as well. The authors carefully detailed these differences based on the straight-leg raising test, femoral stretch test, reflexes, and muscle weakness.
Spine centers from across the United States are part of the SPORT. Patients included in this study had imaging studies that confirmed disc herniation as a cause of the symptoms. Each patient was selected randomly by a computer draw and placed in one of two groups based on treatment received. The groups were: the nonoperative therapy group and the surgical group.
Nonoperative care consisted of patient education and counseling, antiinflammatory drugs, steroid injections, physical therapy, and pain medication. Surgery was a discectomy to remove part or all of the disc.
The goal was to evaluate the effect of surgery based on herniation level. Measures of outcomes or results used included pain, function, and disability. Two instruments were used to measure these categories: the Oswestry Disability Index (ODI) and the Short Form-36 (SF-36). Patients were followed for two full years.
The authors found that no matter at what level the herniation occurred, surgery gave the best results. And patients with upper lumbar herniations did much better than patients with lower lumbar disc herniations. There was also greater improvement with nonoperative care for lower level herniations (compared to upper level problems).
This study showed that herniation level does affect treatment outcomes. This may have to do with the amount of space in the spinal canal as the spinal cord moves down the spine. The diameter of the spinal canal is smaller at the upper levels and gets larger further down the spine.
The direction of the herniation may also make a difference. Discs in the upper lumbar spine are more likely to protrude to the side close to the spinal nerves. It may be easier to remove the disc in this location compared to lower lumbar disc herniation, which is more likely to occur in the posterolateral (back and to the side) direction.