title: Comparison of pedicle screw-based dynamic stabilization and fusion surgery in the treatment of radiographic adjacent-segment degeneration: a retrospective analysis of single L5-S1 degenerative spondylosis covering 4 years.
abstract: OBJECTIVE Pedicle screw-based dynamic spinal stabilization systems (PDSs) were devised to decrease, theoretically, the risk of long-term complications such as adjacent-segment degeneration (ASD) after lumbar fusion surgery. However, to date, there have been few studies that fully proved that a PDS can reduce the risk of ASD. The purpose of this study was to examine whether a PDS can influence the incidence of ASD and to discuss the surgical coping strategy for L5-S1 segmental spondylosis with preexisting L4-5 degeneration with no related symptoms or signs. METHODS This study retrospectively compared 62 cases of L5-S1 segmental spondylosis in patients who underwent posterior lumbar interbody fusion (n = 31) or K-Rod dynamic stabilization (n = 31) with a minimum of 4 years' follow-up. The authors measured the intervertebral heights and spinopelvic parameters on standing lateral radiographs and evaluated preexisting ASD on preoperative MR images using the modified Pfirrmann grading system. Radiographic ASD was evaluated according to the results of radiography during follow-up. RESULTS All 62 patients achieved remission of their neurological symptoms without surgical complications. The Kaplan-Meier curve and Cox proportional-hazards model showed no statistically significant differences between the 2 surgical groups in the incidence of radiographic ASD (p > 0.05). In contrast, the incidence of radiographic ASD was 8.75 times (95% CI 1.955-39.140; p = 0.005) higher in the patients with a preoperative modified Pfirrmann grade higher than 3 than it was in patients with a modified Pfirrmann grade of 3 or lower. In addition, no statistical significance was found for other risk factors such as age, sex, and spinopelvic parameters. CONCLUSIONS Pedicle screw-based dynamic spinal stabilization systems were not found to be superior to posterior lumbar interbody fusion in preventing radiographic ASD (L4-5) during the midterm follow-up. Preexisting ASD with a modified Pfirrmann grade higher than 3 was a risk factor for radiographic ASD. In the treatment of degenerative diseases of the lumbosacral spine, the authors found that both of these methods are feasible. Also, the authors believe that no extra treatment, other than observation, is needed for preexisting degeneration in L4-5 without any clinical symptoms or signs.
authors.affiliation: Department of Orthopedics, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan Province, People's Republic of China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Han
authors.affiliation: Department of Orthopedics, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan Province, People's Republic of China.
authors.forename: Jianguang
authors.initials: J
authors.lastname: Sun
authors.affiliation: Department of Orthopedics, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan Province, People's Republic of China.
authors.forename: Chenghan
authors.initials: C
authors.lastname: Luo
authors.affiliation: Department of Orthopedics, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan Province, People's Republic of China.
authors.forename: Shilei
authors.initials: S
authors.lastname: Huang
authors.affiliation: Department of Orthopedics, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan Province, People's Republic of China.
authors.forename: Liren
authors.initials: L
authors.lastname: Li
authors.affiliation: Department of Orthopedics, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan Province, People's Republic of China.
authors.forename: Xiang
authors.initials: X
authors.lastname: Ji
authors.affiliation: Department of Orthopedics, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan Province, People's Republic of China.
authors.forename: Xiaozong
authors.initials: X
authors.lastname: Duan
authors.affiliation: Department of Orthopedics, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan Province, People's Republic of China.
authors.forename: Zhenqing
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Department of Orthopedics, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan Province, People's Republic of China.
authors.forename: Guofu
authors.initials: G
authors.lastname: Pi
mesh_terms: D000328:Adult; D000359:Aftercare; D005260:Female; D006801:Humans; D015994:Incidence; D055959:Intervertebral Disc Degeneration / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000601:surgery*; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D065289:Pedicle Screws; D012189:Retrospective Studies; D012447:Sacrum / Q000000981:diagnostic imaging / Q000601:surgery*; D013123:Spinal Fusion / Q000295:instrumentation / Q000379:methods*; D055009:Spondylosis / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000601:surgery*; D016896:Treatment Outcome; D055815:Young Adult
keywords: ASD = adjacent-segment degeneration; BMI = body mass index; LL = lumbar lordosis; ODI = Oswestry Disability Index; PDS = pedicle screw–based dynamic spinal stabilization system; PI = pelvic incidence; PLIF = posterior lumbar interbody fusion; PT = pelvic tilt; SS = sacral slope; adjacent-segment degeneration; degenerative; lumbar; pedicle screw–based dynamic spinal stabilization system; preexisting adjacent-segment degeneration; risk factor; spinal fusion