Demineralization after balloon kyphoplasty with calcium phosphate cement: a histological evaluation in ten patients
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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.
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.
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.
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.
KeywordsBalloon kyphoplasty Biocompatibility Bone biopsy Calcium phosphate cement Histology Osseointegration Vertebra
The authors would like to thank Professor Seggl for providing approval to perform the study. All authors would like to thank Medtronic for their support for the study. RG would also like to thank N. Stockenhuber who introduced the BKP with CPC procedure to his hospital and provided assistance based on his extensive experience. The authors would also like to thank Dr. Richard Barry (Quintiles Medical Communications) for medical writing assistance, which was funded by Medtronic.
Conflict of interest
The authors declare that they have no conflict of interest.
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