title: Demineralization after balloon kyphoplasty with calcium phosphate cement: a histological evaluation in ten patients.
abstract: OBJECTIVE
  Balloon kyphoplasty (BKP) with calcium phosphate cement (CPC) is increasingly being used for spinal surgery in younger patients. In routinely performed follow-up CT scans we observed considerable areas of demineralization in CPC processed vertebrae in several patients. To rule out infections or inflammations histological examinations were planned for these patients.
  
  
  METHODS
  Ten patients (23-54 years; six men) with significant demineralization areas in CT scans after CPC balloon kyphoplasty were selected. Punch biopsies from these areas were taken in local anesthesia using a biopsy needle. One half of the specimen was decalcified and embedded in paraffin, and sections were examined histologically using hematoxylin and eosin, Van Gieson, and trichrome staining. The second half of the specimen was cast directly in methyl methacrylate and sections were examined by Paragon and von Kossa/Safranin staining. Stained slides were viewed under light microscopy.
  
  
  RESULTS
  Bone-punch specimens were taken at 17.5 months (mean) after BKP with CPC. In most cases, the cement was well surrounded by newly formed lamellar bone with very tight connections between the cement and new bone. Unmineralized areas were observed sporadically at the cement surface and adjacent to the implant. There were no pronounced signs of inflammation or osteolysis of adjacent bone. No complications were observed during or following patients' biopsy procedures.
  
  
  CONCLUSIONS
  CPC demonstrated good biocompatibility and osseointegration in clinical use, with no evidence of inflammation or osteonecrosis. Demineralized areas in CT scans could be a result of remodeling of the cancellous bone in vertebral bodies.
authors.affiliation: Department of Traumatology, Medical University Graz (MUG), Auenbruggerplatz 5, 8036, Graz, Austria.
authors.forename: Rainer
authors.initials: R
authors.lastname: Gumpert
authors.forename: Koppany
authors.initials: K
authors.lastname: Bodo
authors.forename: Ekkehard
authors.initials: E
authors.lastname: Spuller
authors.forename: Thomas
authors.initials: T
authors.lastname: Poglitsch
authors.forename: Ronny
authors.initials: R
authors.lastname: Bindl
authors.forename: Anita
authors.initials: A
authors.lastname: Ignatius
authors.forename: Paul
authors.initials: P
authors.lastname: Puchwein
mesh_terms: D000328:Adult; D001707:Biopsy, Needle; D001843:Bone Cements; D018488:Bone Demineralization, Pathologic; D002130:Calcium Phosphates; D006801:Humans; D058498:Kyphoplasty; D008297:Male; D008853:Microscopy; D008875:Middle Aged; D016348:Osseointegration; D010006:Osteoblasts / Q000473:pathology; D016103:Spinal Fractures / Q000601:surgery; D013131:Spine / Q000473:pathology*; D014057:Tomography, X-Ray Computed; D055815:Young Adult
chemical_list: D001843:Bone Cements; D002130:Calcium Phosphates