title: First clinical results of minimally invasive vector lumbar interbody fusion (MIS-VLIF) in spondylodiscitis and concomitant osteoporosis: a technical note.
abstract: First description of MIS-VLIF, a minimally invasive lumbar stabilization, to evaluate its safety and feasibility in patients suffering from weak bony conditions (lumbar spondylodiscitis and/or osteoporosis).
  
  
  
  After informed consent, 12 patients suffering from lumbar spondylodiscitis underwent single level MIS-VLIF. Eight of them had a manifest osteoporosis, either. Pre- and postoperative clinical status was documented using numeric rating scale (NRS) for leg and back pain. In all cases, the optimal height for the cage was preoperatively determined using software-based range of motion and sagittal balance analysis. CT scans were obtained to evaluate correct placement of the construct and to verify fusion after 6 months.
  
  
  
  Since 2013, 12 patients with lumbar pyogenic spondylodiscitis underwent MIS-VLIF. Mean surgery time was 169 ± 28 min and average blood loss was less than 400 ml. Postoperative CT scans showed correct placement of the implants. Eleven patients showed considerable postoperative improvement in clinical scores. In one patient, we observed screw loosening. After documented bony fusion in the CT scan, the fixation system was removed in two cases to achieve lower material load.
  
  
  
  The load-bearing trajectories (vectors) of MIS-VLIF are different from those of conventional coaxial pedicle screw implantation. The dorsally converging construct combines the heads of the dorsoventral pedicle screws with laminar pedicle screws following cortical bone structures within a small approach. In case of lumbar spondylodiscitis and/or osteoporosis, MIS-VLIF relies on cortical bony structures for all screw vectors and the construct does not depend on conventional coaxial pedicle screws in the presence of inflamed, weak, cancellous or osteoporotic bone. MIS-VLIF allows full 360° lumbar fusion including cage implantation via a small, unilateral dorsal midline approach.
authors.affiliation: Department of Neurosurgery, Carl Gustav Carus University Hospital, Technical University of Dresden, 01307, Dresden, Germany. biokinemetrie@gmail.com.|Spine Center DWG Level I, Carl Gustav Carus University Hospital, Technical University of Dresden, 01307, Dresden, Germany. biokinemetrie@gmail.com.
authors.forename: Bernhard
authors.initials: B
authors.lastname: Rieger
authors.affiliation: Department of Neurosurgery, Carl Gustav Carus University Hospital, Technical University of Dresden, 01307, Dresden, Germany.|Spine Center DWG Level I, Carl Gustav Carus University Hospital, Technical University of Dresden, 01307, Dresden, Germany.|Department of Neurosurgery, Chinese PLA General Hospital, Beijing, 100853, China.
authors.forename: Hongzhen
authors.initials: H
authors.lastname: Jiang
authors.affiliation: Department of Stereotactic and Functional Neurosurgery, University of Cologne, 50937, Cologne, Germany.
authors.forename: Daniel
authors.initials: D
authors.lastname: Ruess
authors.affiliation: Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
authors.forename: Clemens
authors.initials: C
authors.lastname: Reinshagen
authors.affiliation: Institute of Neurophysiology, Medical Faculty, University of Cologne, 50937, Cologne, Germany. Department of Neurosurgery, Research Unit for Experimental Neurotraumatology, Medical University Graz, Graz, Austria.
authors.forename: Marek
authors.initials: M
authors.lastname: Molcanyi
authors.affiliation: Department of Biomedical Engineering, Technical University of Kosice, 04000, Kosice, Slovakia.
authors.forename: Jozef
authors.initials: J
authors.lastname: Zivcak
authors.affiliation: Department of Neurosurgery, Chinese PLA General Hospital, Beijing, 100853, China.
authors.forename: Huaiyu
authors.initials: H
authors.lastname: Tong
authors.affiliation: Department of Neurosurgery, Carl Gustav Carus University Hospital, Technical University of Dresden, 01307, Dresden, Germany.|Spine Center DWG Level I, Carl Gustav Carus University Hospital, Technical University of Dresden, 01307, Dresden, Germany.
authors.forename: Gabriele
authors.initials: G
authors.lastname: Schackert
mesh_terms: D015299:Discitis / Q000150:complications / Q000000981:diagnostic imaging / Q000601:surgery; D006801:Humans; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000601:surgery; D019060:Minimally Invasive Surgical Procedures / Q000009:adverse effects / Q000379:methods / Q000706:statistics & numerical data; D010024:Osteoporosis / Q000150:complications*; D013123:Spinal Fusion / Q000009:adverse effects / Q000379:methods / Q000706:statistics & numerical data; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome
keywords: Biokinemetrie; Minimally invasive surgery; Osteoporosis; Spondylodiscitis; Vector-LIF