title: Cement-augmented anterior screw fixation of Type II odontoid fractures in elderly patients with osteoporosis.
abstract: BACKGROUND
  Closed reduction and internal fixation by an anterior approach is an established option for operative treatment of displaced Type II odontoid fractures. In elderly patients, however, inadequate screw purchase in osteoporotic bone can result in severe procedure-related complications.
  
  
  OBJECTIVE
  To improve the stability of odontoid fracture screw fixation in the elderly using a new technique that includes injection of polymethylmethacrylat (PMMA) cement into the C2 body.
  
  
  METHODS
  Retrospective review of hospital and outpatient records as well as radiographs of elderly patients treated in a university hospital department of orthopedic surgery.
  
  
  METHODS
  Twenty-four elderly patients (8 males and 16 females; mean age, 81 years; range, 62-98 years) with Type II fractures of the dens.
  
  
  METHODS
  Complications, cement leakage (symptomatic/asymptomatic), operation time, loss of reduction, pseudarthrosis and revision surgery, patient complaints, return to normal activities, and signs of neurologic complications were all documented.
  
  
  METHODS
  After closed reduction and anterior approach to the inferior border of C2, a guide wire is advanced to the tip of the odontoid under biplanar fluoroscopic control. Before the insertion of one cannulated, self-drilling, short thread screws, a 12 gauge Yamshidi cannula is inserted from anterior and 1 to 3 mL of high-viscosity PMMA cement is injected into the anteroinferior portion of the C2 body. During polymerization of the cement, the screws are further inserted using a lag-screw compression technique. The cervical spine then is immobilized with a soft collar for 8 weeks postoperatively.
  
  
  RESULTS
  Anatomical reduction of the dens was achieved in all 24 patients. Mean operative time was 64 minutes (40-90 minutes). Early loss of reduction occurred in three patients, but revision surgery was indicated in only one patient 2 days after primary surgery. One patient died within the first eight postoperative weeks, one within 3 months after surgery. In five patients, asymptomatic cement leakage was observed (into the C1-C2 joint in three patients, into the fracture in two). Conventional radiologic follow-up at 2 and 6 months confirmed anatomical healing in 16 of the 19 patients with complete follow-up. In two patients, the fractures healed in slight dorsal angulation; one patient developed a asymptomatic pseudarthrosis. All patients were able to resume their pretrauma level of activity.
  
  
  CONCLUSIONS
  Cement augmentation of the screw in Type II odontoid fractures in elderly patients is technically feasible in a clinical setting with a low complication rate. This technique may improve screw purchase, especially in the osteoporotic C2 body.
authors.affiliation: Department of Orthopedic Surgery and Traumatology, Inselspital, University Hospital of Berne, 3010 Bern, Switzerland; Department of Orthopedic Surgery and Traumatology, University and University Hospitals of Bonn, Sigmund-Freud-Str. 25, 53127 Bonn, Germany.
authors.forename: Hendrik
authors.initials: H
authors.lastname: Kohlhof
authors.forename: Ulrich
authors.initials: U
authors.lastname: Seidel
authors.forename: Sven
authors.initials: S
authors.lastname: Hoppe
authors.forename: Marius J
authors.initials: MJ
authors.lastname: Keel
authors.forename: Lorin M
authors.initials: LM
authors.lastname: Benneker
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001843:Bone Cements / Q000627:therapeutic use; D001863:Bone Screws; D005260:Female; D005593:Fracture Fixation, Internal / Q000295:instrumentation / Q000379:methods; D006801:Humans; D008297:Male; D008875:Middle Aged; D009809:Odontoid Process / Q000601:surgery*; D010024:Osteoporosis / Q000150:complications*; D019904:Polymethyl Methacrylate / Q000627:therapeutic use; D011183:Postoperative Complications / Q000453:epidemiology; D012189:Retrospective Studies; D016103:Spinal Fractures / Q000209:etiology / Q000601:surgery*; D013123:Spinal Fusion / Q000295:instrumentation* / Q000379:methods*
chemical_list: D001843:Bone Cements; D019904:Polymethyl Methacrylate
keywords: Augmentation; Cement; Dens fracture; Screw; Type II odontoid fracture