title: Analysis of the Factors Contributing to Vertebral Compression Fractures After Spine Stereotactic Radiosurgery.
abstract: To determine our institutional vertebral compression fracture (VCF) rate after spine stereotactic radiosurgery (SRS) and determine contributory factors.
  
  
  
  Retrospective analysis from 2001 to 2013 at a single institution was performed. With institutional review board approval, electronic medical records of 1905 vertebral bodies from 791 patients who were treated with SRS for the management of primary or metastatic spinal lesions were reviewed. A total of 448 patients (1070 vertebral bodies) with adequate follow-up imaging studies available were analyzed. Doses ranging from 10 Gy in 1 fraction to 60 Gy in 5 fractions were delivered. Computed tomography and magnetic resonance imaging were used to evaluate the primary endpoints of this study: development of a new VCF, progression of an existing VCF, and requirement of stabilization surgery after SRS.
  
  
  
  A total of 127 VCFs (11.9%; 95% confidence interval [CI] 9.5%-14.2%) in 97 patients were potentially SRS induced: 46 (36%) were de novo, 44 (35%) VCFs progressed, and 37 (29%) required stabilization surgery after SRS. Our rate for radiologic VCF development/progression (excluding patients who underwent surgery) was 8.4%. Upon further exclusion of patients with hematologic malignancies the VCF rate was 7.6%. In the univariate analyses, females (hazard ratio [HR] 1.54, 95% CI 1.01-2.33, P=.04), prior VCF (HR 1.99, 95% CI 1.30-3.06, P=.001), primary hematologic malignancies (HR 2.68, 95% CI 1.68-4.28, P<.001), thoracic spine lesions (HR 1.46, 95% CI 1.02-2.10, P=.02), and lytic lesions had a significantly increased risk for VCF after SRS. On multivariate analyses, prior VCF and lesion type remained contributory.
  
  
  
  Single-fraction SRS doses of 16 to 18 Gy to the spine seem to be associated with a low rate of VCFs. To the best of our knowledge, this is the largest reported experience analyzing SRS-induced VCFs, with one of the lowest event rates reported.
authors.affiliation: Department of Radiation Oncology, Henry Ford Health System, Detroit, Michigan.
authors.forename: David
authors.initials: D
authors.lastname: Boyce-Fappiano
authors.affiliation: Department of Radiation Oncology, Henry Ford Health System, Detroit, Michigan.
authors.forename: Erinma
authors.initials: E
authors.lastname: Elibe
authors.affiliation: Department of Neurosurgery, Henry Ford Health System, Detroit, Michigan.
authors.forename: Lonni
authors.initials: L
authors.lastname: Schultz
authors.affiliation: Department of Radiation Oncology, Stony Brook University School of Medicine, Stony Brook, New York.
authors.forename: Samuel
authors.initials: S
authors.lastname: Ryu
authors.affiliation: Department of Radiation Oncology, Henry Ford Health System, Detroit, Michigan.
authors.forename: M Salim
authors.initials: MS
authors.lastname: Siddiqui
authors.affiliation: Department of Radiation Oncology, Henry Ford Health System, Detroit, Michigan.
authors.forename: Indrin
authors.initials: I
authors.lastname: Chetty
authors.affiliation: Department of Neurosurgery, Henry Ford Health System, Detroit, Michigan.
authors.forename: Ian
authors.initials: I
authors.lastname: Lee
authors.affiliation: Department of Neurosurgery, Henry Ford Health System, Detroit, Michigan.
authors.forename: Jack
authors.initials: J
authors.lastname: Rock
authors.affiliation: Department of Radiation Oncology, Henry Ford Health System, Detroit, Michigan.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Movsas
authors.affiliation: Department of Radiation Oncology, Henry Ford Health System, Detroit, Michigan. Electronic address: fsiddiq2@hfhs.org.
authors.forename: Farzan
authors.initials: F
authors.lastname: Siddiqui
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D016001:Confidence Intervals; D018450:Disease Progression; D005260:Female; D005592:Fracture Fixation / Q000379:methods / Q000706:statistics & numerical data; D050815:Fractures, Compression / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000209:etiology* / Q000601:surgery; D019337:Hematologic Neoplasms / Q000150:complications; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D016634:Radiosurgery / Q000009:adverse effects* / Q000706:statistics & numerical data; D011879:Radiotherapy Dosage; D012189:Retrospective Studies; D012307:Risk Factors; D012737:Sex Factors; D016103:Spinal Fractures / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000209:etiology* / Q000601:surgery; D013125:Spinal Neoplasms / Q000532:radiotherapy* / Q000556:secondary; D014057:Tomography, X-Ray Computed