Question: In patients with severe chronic low-back pain requiring posterolateral spinal arthrodesis, is the long-term outcome after supplemental pedicle-screw fixation (instrumented) better than that after spinal arthrodesis without pedicle-screw instrumentation (noninstrumented)?
Design: Randomized (allocation concealed)*, blinded (data collectors and outcome assessors)*, controlled trial with a 5-year follow-up.
Setting: A university hospital in Aarhus, Denmark.
Patients: 130 patients (mean age, 45 years [range, 20 to 70 years]; 53% women) who had severe chronic low-back pain because of localized lumbar or lumbosacral segmental instability due to Grade-I or Grade-II isthmic spondylolisthesis, primary degenerative instability, secondary degenerative instability after surgical decompression, or accelerating degenerative instability after surgical decompression. Exclusion criteria were a previous arthrodesis, metabolic bone disease including osteoporosis, ≥1 comorbidity, and psychosocial instability. 93% of the patients had complete follow-up.
Intervention: Patients undergoing a posterolateral spinal arthrodesis were allocated to the instrumented group, which was managed with supplemental pedical-screw fixation with Cotrel-Dubousset instrumentation ( n = 64), or to the noninstrumented group, which was managed with posterolateral intertransverse arthrodesis without supplemental fixation ( n = 66).
Main outcome measures: Functional outcome was assessed with use of the Dallas Pain Questionnaire (DPQ) and the Low Back Pain Rating Scale (LBPR) (a 10-point scale, with 0 indicating no pain and 10 indicating the worst pain, that included 3 questions on low-back pain and 3 on leg pain).
Main results: Surgical time (P < 0.0001), blood loss (P < 0.01), and reoperation rates (P = 0.03) were greater in patients in the instrumented group. Functional outcome improved after spinal arthrodesis, with no significant differences found between the groups with respect to the measures obtained in any category on the DPQ or the LBPR. However, patients in the noninstrumented group who had isthmic spondylolisthesis had greater improvement than the patients in the instrumented group with respect to their response to the questions in 3 of 4 categories of the DPQ and their responses to all questions on back pain in the LPBR. Patients in the instrumented group who had primary degenerative instability had greater improvement than the patients in the noninstrumented group with respect to their responses to questions in the work and leisure category of the DPQ and to all 6 questions on back and leg pain in the LBPR. The study had the power to detect a difference of ≥15 points in the DPQ score.
Conclusion: In patients with severe chronic low-back pain, posterolateral spinal arthrodesis with supplemental pedicle-screw instrumentation was no more effective than arthrodesis without pedicle-screw instrumentation with regard to long-term functional outcome.
Long-term functional outcome of pedicle screw instrumentation as a support for posterolateral spinal fusion: randomized clinical study with a 5-year follow-up. Spine. 2002 Jun 15;27:1269-77.
Source of funding: No external funding.
*Information provided by author.
For correspondence: Dr. F. Bjarke Christensen, Orthopedic Research Laboratory, University Hospital of Aarhus, Norrebrogade 44, DK-8000 Aarhus C, Denmark. E-mail address: firstname.lastname@example.org.