What Are Long-term Predictors of Outcomes for Lumbar Disc Herniation? A Randomized and Observational Study.

BACKGROUND

Although previous studies have illustrated improvements in surgical cohorts for patients with intervertebral disc herniation, there are limited data on predictors of long-term outcomes comparing surgical and nonsurgical outcomes.

QUESTIONS/PURPOSES: We assessed outcomes of operative and nonoperative treatment for patients with intervertebral disc herniation and symptomatic radiculopathy at 8 years from the Spine Patient Outcomes Research Trial. We specifically examined subgroups to determine whether certain populations had a better long-term outcome with surgery or nonoperative treatment.

METHODS

Patients with symptomatic lumbar radiculopathy for at least 6 weeks associated with nerve root irritation or neurologic deficit on examination and a confirmed disc herniation on cross-sectional imaging were enrolled at 13 different clinical sites. Patients consenting to participate in the randomized cohort were assigned to surgical or nonoperative treatment using variable permuted block randomization stratified by site. Those who declined randomization entered the observational cohort group based on treatment preference but were otherwise treated and followed identically to the randomized cohort. Of those in the randomized cohort, 309 of 501 (62%) provided 8-year data and in the observational group 469 of 743 (63%). Patients were treated with either surgical discectomy or usual nonoperative care. By 8 years, only 148 of 245 (60%) of those randomized to surgery had undergone surgery, whereas 122 of 256 (48%) of those randomized to nonoperative treatment had undergone surgery. The primary outcome measures were SF-36 bodily pain, SF-36 physical function, and Oswestry Disability Index collected at 6 weeks, 3 months, 6 months, 12 months, and then annually. Further analysis studied the following factors to determine if any were predictive of long-term outcomes: sex, herniation location, depression, smoking, work status, other joint problems, herniation level, herniation type, and duration of symptoms.

RESULTS

The intent-to-treat analysis of the randomized cohort at 8 years showed no difference between surgical and nonoperative treatment for the primary outcome measures. Secondary outcome measures of sciatica bothersomeness, leg pain, satisfaction with symptoms, and self-rated improvement showed greater improvement in the group randomized to surgery despite high levels of crossover. The as-treated analysis of the combined randomized and observational cohorts, adjusted for potential confounders, showed advantages for surgery for all primary outcome measures; however, this has the potential for confounding from other unrecognized variables. Smokers and patients with depression or comorbid joint problems had worse functional outcomes overall (with surgery and nonoperative care) but similar surgical treatment effects. Patients with sequestered fragments, symptom duration greater than 6 months, those with higher levels of low back pain, or who were neither working nor disabled at baseline showed greater surgical treatment effects.

CONCLUSIONS

The intent-to-treat analysis, which is complicated by high rates of crossover, showed no difference over 8 years for primary outcomes of overall pain, physical function, and back-related disability but did show small advantages for secondary outcomes of sciatica bothersomeness, satisfaction with symptoms, and self-rated improvement. Subgroup analyses identified those groups with sequestered fragments on MRI, higher levels of baseline back pain accompanying radiculopathy, a longer duration of symptoms, and those who were neither working nor disabled at baseline with a greater relative advantage from surgery at 8 years.

LEVEL OF EVIDENCE

Level II, therapeutic study. See Instructions for Authors for a complete description of levels of evidence.