title: Minimally Invasive Technique for PMMA Augmentation of Fenestrated Screws.
abstract: OBJECTIVE
  To describe the minimally invasive technique for cement augmentation of cannulated and fenestrated screws using an injection cannula as well as to report its safety and efficacy.
  
  
  METHODS
  A total of 157 cannulated and fenestrated pedicle screws had been cement-augmented during minimally invasive posterior screw-rod spondylodesis in 35 patients from January to December 2012. Retrospective evaluation of cement extravasation and screw loosening was carried out in postoperative plain radiographs and thin-sliced triplanar computed tomography scans.
  
  
  RESULTS
  Twenty-seven, largely prevertebral cement extravasations were detected in 157 screws (17.2%). None of the cement extravasations was causing a clinical sequela like a new neurological deficit. One screw loosening was noted (0.6%) after a mean follow-up of 12.8 months. We observed no cementation-associated complication like pulmonary embolism or hemodynamic insufficiency.
  
  
  CONCLUSIONS
  The presented minimally invasive cement augmentation technique using an injection cannula facilitates convenient and safe cement delivery through polyaxial cannulated and fenestrated screws during minimally invasive screw-rod spondylodesis. Nevertheless, the optimal injection technique and design of fenestrated screws have yet to be identified. This trial is registered with German Clinical Trials DRKS00006726.
authors.affiliation: Department of Neurosurgery, Freiburg University Medical Center, Breisacher Straße 64, 79106 Freiburg im Breisgau, Germany.
authors.forename: Jan-Helge
authors.identifier: 0000-0003-3469-9027
authors.initials: JH
authors.lastname: Klingler
authors.affiliation: Department of Neurosurgery, Freiburg University Medical Center, Breisacher Straße 64, 79106 Freiburg im Breisgau, Germany.
authors.forename: Christoph
authors.identifier: 0000-0003-1469-2901
authors.initials: C
authors.lastname: Scholz
authors.affiliation: Department of Neurosurgery, Freiburg University Medical Center, Breisacher Straße 64, 79106 Freiburg im Breisgau, Germany.
authors.forename: Evangelos
authors.initials: E
authors.lastname: Kogias
authors.affiliation: Department of Neurosurgery, Freiburg University Medical Center, Breisacher Straße 64, 79106 Freiburg im Breisgau, Germany.
authors.forename: Ronen
authors.initials: R
authors.lastname: Sircar
authors.affiliation: Department of Neurosurgery, Freiburg University Medical Center, Breisacher Straße 64, 79106 Freiburg im Breisgau, Germany.
authors.forename: Marie T
authors.initials: MT
authors.lastname: Krüger
authors.affiliation: Department of Neurosurgery, Freiburg University Medical Center, Breisacher Straße 64, 79106 Freiburg im Breisgau, Germany.
authors.forename: Florian
authors.initials: F
authors.lastname: Volz
authors.affiliation: Department of Neurosurgery, Freiburg University Medical Center, Breisacher Straße 64, 79106 Freiburg im Breisgau, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Scheiwe
authors.affiliation: Department of Neurosurgery, Freiburg University Medical Center, Breisacher Straße 64, 79106 Freiburg im Breisgau, Germany.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Hubbe
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001843:Bone Cements; D005260:Female; D006801:Humans; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000293:injuries / Q000473:pathology / Q000601:surgery; D008297:Male; D008875:Middle Aged; D019060:Minimally Invasive Surgical Procedures / Q000009:adverse effects / Q000379:methods*; D065289:Pedicle Screws; D019904:Polymethyl Methacrylate; D011183:Postoperative Complications; D011859:Radiography; D012189:Retrospective Studies; D013123:Spinal Fusion / Q000379:methods; D013131:Spine / Q000601:surgery; D016896:Treatment Outcome
chemical_list: D001843:Bone Cements; D019904:Polymethyl Methacrylate