title: Risk factors and surgical treatment for symptomatic adjacent segment degeneration after lumbar spine fusion.
abstract: OBJECTIVE
  The present study analyzed the risk factors, prevalence and clinical results following revision surgery for adjacent segment degeneration (ASD) in patients who had undergone lumbar fusion.
  
  
  METHODS
  Over an 8-year period, we performed posterior lumbar fusion in 81 patients. Patients were followed a minimum of 2 years (mean 5.5 years). During that time, 9 patients required revision surgery due to ASD development. Four patients underwent autogenous posterolateral arthrodesis and extended transpedicle screw fixation, 4 patients underwent decompressive laminectomy and interspinous device implantation, and 1 patient underwent simple decompression.
  
  
  RESULTS
  Of the 9 of patients with clinical ASD, 33.3% (3 of 9) of patients did not have radiographic ASD on plain radiographs. Following revision surgery, the clinical results were excellent or good in 8 patients (88.9%). Age > 50 years at primary surgery was a significant risk factor for ASD development, while number of fusion levels, initial diagnosis and type of fusion were not.
  
  
  CONCLUSIONS
  The incidence of ASD development after lumbar surgery was 11.1% (9 of 81) in this study. Age greater than 50 was the statistically significant risk factor for ASD development. Similar successful clinical outcomes were observed after extended fusion with wide decompression or after interspinous device implantation. Given the latter procedure is less invasive, the findings suggest it may be considered a treatment alternative in selected cases but it needs further study.
authors.affiliation: Department of Neurosurgery, Uijeongbu St. Mary's Hospital, The Catholic University College of Medicine, Uijeongbu, Korea.
authors.forename: Kyoung-Suok
authors.initials: KS
authors.lastname: Cho
authors.forename: Suk-Gu
authors.initials: SG
authors.lastname: Kang
authors.forename: Do-Sung
authors.initials: DS
authors.lastname: Yoo
authors.forename: Pil-Woo
authors.initials: PW
authors.lastname: Huh
authors.forename: Dal-Soo
authors.initials: DS
authors.lastname: Kim
authors.forename: Sang-Bok
authors.initials: SB
authors.lastname: Lee