Adjacent segment disease followinglumbar/thoracolumbar fusion with pedicle screw instrumentation: a minimum 5-year follow-up

Spine (Phila Pa 1976). 2007 Sep 15;32(20):2253-7. doi: 10.1097/BRS.0b013e31814b2d8e.


Study design: Retrospective radiographic outcomes analysis.

Objective: We had 3 hypotheses: 1) a longer fusion; 2) a more proximal instrumented vertebra, and 3) circumferential fusion versus posterior-only fusion would increase the likelihood of adjacent segment disease (ASD).

Summary of background data: The literature analyzing risk factors, prevalence, and presentation of patients with ASD is varied and without clear consensus.

Methods: A total of 188 patients with minimum 5-year follow-up who had lumbar/thoracolumbar fusion with pedicle screw instrumentation for degenerative disorders were included. Radiographic ASD was defined by: 1) development of spondylolisthesis >4 mm, 2) segmental kyphosis >10 degrees , 3) complete collapse of disc space, or 4) more than 2 grades worsening of Weiner classification. Clinical ASD was defined as 1) symptomatic spinal stenosis, 2) intractable back pain, or 3) subsequent sagittal or coronal imbalance.

Results: Radiographic ASD occurred in 42.6% (80 of 188) of patients. Patients with radiographic ASD had worse Oswestry scores (20.3 vs. 12.5; P = 0.001) at ultimate follow-up than those without ASD. Clinical ASD developed in 30.3% (57 of 188) of patients. Clinical ASD manifested as spinal stenosis (n = 47), instability-type back pain (n = 5), and sagittal or coronal imbalance (n = 5). Age at surgery over 50 years and length of fusion were significant risk factors for the development of ASD in the lumbar spine. Fusion to L1-L3 proximally increased the risk of ASD when compared with L4 and L5. Circumferential fusion versus posterior fusion was not a significant factor in the development of ASD.

Conclusion: Patients over the age of 50 were at higher risk of developing clinical ASD than those 50 years old or younger. Length of fusion was a significant risk factor in the development of ASD in the lumbar spine. Fusion up to L1-L3 increased the risk of ASD when compared with L4 and L5. Circumferential fusion, as opposed to posterolateral fusion, was not a statistically significant risk factor for the development of ASD.

Publication types

  • Comparative Study

MeSH terms

  • Adult
  • Age Factors
  • Aged
  • Aged, 80 and over
  • Back Pain / etiology
  • Bone Screws*
  • Disability Evaluation
  • Disease Progression
  • Female
  • Follow-Up Studies
  • Humans
  • Kyphosis / etiology
  • Lumbar Vertebrae / diagnostic imaging
  • Lumbar Vertebrae / physiopathology
  • Lumbar Vertebrae / surgery*
  • Male
  • Middle Aged
  • Pain, Intractable / etiology
  • Postural Balance
  • Prevalence
  • Radiography
  • Recovery of Function
  • Retrospective Studies
  • Risk Assessment
  • Risk Factors
  • Severity of Illness Index
  • Spinal Diseases / diagnostic imaging
  • Spinal Diseases / epidemiology
  • Spinal Diseases / etiology*
  • Spinal Diseases / physiopathology
  • Spinal Fusion / instrumentation*
  • Spinal Fusion / methods
  • Spinal Stenosis / etiology
  • Spondylolisthesis / etiology
  • Thoracic Vertebrae / diagnostic imaging
  • Thoracic Vertebrae / physiopathology
  • Thoracic Vertebrae / surgery*
  • Time Factors
  • Treatment Outcome