Effectiveness of Microdiscectomy for Lumbar Disc Herniation: A Randomized Controlled Trial With 2 Years of Follow-up

Heikki Österman, MD; Seppo Seitsalo, MD, PhD; Jaro Karppinen, MD, PhD; Antti Malmivaara, MD, PhD


Spine. 2006;31(21):2409-2414. 

In This Article




Adherence and Cointerventions

All the 28 patients in the surgical group underwent surgery. There were two reoperations because of recurring symptoms on the same side and level. The reoperations took place 6 weeks and 19 months after initial surgery.

Eleven patients in the control group crossed over to surgery eventually. Indications for surgery were unbearable continuing pain (in 7), recurring symptoms after initial improvement (in 3), and progressive motor weakness (in 1). The local study orthopedist made the decision about operation. Three operations were performed before the 6-week follow-up (unbearable pain), 4 between the 6-week and 3-month follow-up (unbearable pain in 2, 1 progressive motor weakness, 1 recurrence), 3 between the 3-month and 6-month follow-up (unbearable pain in 2, 1 recurrence), and 1 between the 6-month and 1-year follow-up (recurrence).

Fifteen patients in the control group and eight in the surgical group reported having had additional physical therapy during the follow-up. The average number of visits was 12 (range, 1-34) in the control group and 9 (range, 1-25) in the surgical group.

One patient in the surgical group had urosepsis needing intravenous antibiotics and prolonged stay in the hospital. No other operative complications were noted.

Patient and Physician Expectations

Because of the surgical intervention, it was not possible to blind the patients or the treating personnel. To assess any possible preferences toward the treatments, both the patients and the physicians were asked immediately after randomization on a scale from 0 to 6 how confident they were that the treatment would help (0 = no confidence, 6 = maximal confidence). In addition, patients were asked to what extent they believed to become symptom-free and able to work eventually (6 indicating complete disappearance of symptoms and full recovery of work ability). Patients' median expectations on getting help, becoming symptom-free, and recovering work ability were 6.0, 5.0, and 6.0 in the surgical group and 5.0 (P = 0.041), 5.0, and 5.0 in the control group. Physicians' median expectations on the treatment effect were 5.0 in the surgical group and 3.5 (P < 0.001) in the control group.


The repeated measures model showed no statistically significant differences between the groups for leg pain intensity, back pain intensity, Oswestry disability, health-related quality of life 15D, work ability, or risk of depression ( Table 2 ). At each follow-up, the surgical group fared better, but the differences in group means were statistically significant only for leg pain intensity at 6 weeks and for satisfaction with treatment at 6 weeks, 6 months, and 2 years. At 6 weeks, 5 patients in the surgical group reported complete recovery ( Table 2 ). Lumbar flexion and lateral bending, straight leg raising positivity, and muscle weakness displayed no differences between the groups ( Table 2 ).

Additional Analyses

The on-treatment analysis compared all the operated patients (28 initially allocated to surgery, 11 crossing over from the control group) with patients who stayed in the control group throughout the follow-up. There were no statistically significant differences between the on-treatment groups.

In the subgroup analyses, men and women did not differ from each other, neither were there any differences when patients with more than median leg pain at baseline (40/100 mm VAS) were compared with patients with less than median pain. There were, however, significant differences associated with the age of the patients and the level of disc herniation. Surgical treatment was associated with less leg pain, less disability, and improved generic health-related quality of life in patients older than median (37 years). Surgical treatment was also associated with statistically significantly improved leg and back pain, Oswestry disability, generic health-related quality of life, and subjective work ability when the disc herniation was at L4-L5. For disc herniations at L5-S1, however, there were no significant differences in these outcomes.

Patients with a primary discectomy both at L4-L5 and L5-S1 had good results at 2 years (average leg pain, 2 ± 4 and 11 ± 16, respectively). Good results were likewise seen at 2 years in both L4-L5 and L5-S1 patients who had remained in the control group (average leg pain, 6 ± 11 and 6 ± 9, respectively). Crossover patients' pain and disability at 2 years were significantly worse when the herniation was at L4-L5 (7 patients, average leg pain, 41 ± 35) but not when it was at L5-S1 (4 patients, average leg pain, 5 ± 10).


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