Repair of calvarial defects in rats by prefabricated hydroxyapatite cement implants.

The aim of the present study was to test the hypothesis that calvarial defects can be repaired by using preformed implants of calcium phosphate bone cement (CPBC) in rats. Sixty adult female Sprague-Dawley rats received full-thickness calvarial nonhealing defects with a diameter of 8 mm. Three different CPBCs were used: group 1: tetracalcium phosphate-based powder; group 2: a blend of amorphous and crystalline calcium phosphate precursors; and group 3: an alpha-tricalcium phosphate (alpha-TCP)-based powder. Implants were left to cure for 25-40 min at room temperature in a silicon mold of 7.9 mm and inserted press fit into the defects. Fifteen animals served as unfilled controls. After 13, 26, and 52 weeks, the material was analyzed qualitatively by using surface-stained undecalcified thick-section specimens and quantitatively by using semiautomated histometry. Kruskal-Wallis tests were applied to compare mean values of periimplant bone formation at a significance level of p < 0.05. Three implants of group 1 fractured during insertion. Resorption of CPBC without complementary bone formation was noticed in these implants. Unfractured implants were resorbed with simultaneous apposition of bone on the implant surface. After 52 weeks, the resorption rate varied between 23.1 and 39.3%. Periimplant bone formation increased continuously on average around all implant types, but it reached statistical significance only in group 2. The results showed that repair of calvarial defects can be achieved by preformed CPBC implants. The rate of resorption of preformed implants is, however, much lower than that reported for in vivo cured CPBC.

[1]  U. Sinha,et al.  Frontotemporal reconstruction with hydroxyapatite cement and the radial forearm free flap. , 2001, Archives of facial plastic surgery.

[2]  J. Planell,et al.  Limited compliance of some apatitic calcium phosphate bone cements with clinical requirements , 1998, Journal of materials science. Materials in medicine.

[3]  A. Gosain,et al.  Hydroxyapatite cement paste cranioplasty for the treatment of temporal hollowing after cranial vault remodeling in a growing child. , 1997, The Journal of craniofacial surgery.

[4]  J. Piepmeier,et al.  Reconstruction of suboccipital craniectomy defects with hydroxyapatite cement: A preliminary report , 1995, The Laryngoscope.

[5]  M. Nagayama,et al.  Initial histological evaluation of anti-washout type fast-setting calcium phosphate cement following subcutaneous implantation. , 1998, Biomaterials.

[6]  J. Planell,et al.  Effect of calcium carbonate on clinical compliance of apatitic calcium phosphate bone cement. , 1997, Journal of biomedical materials research.

[7]  J. Bardach,et al.  Repair of craniofacial defects with hydroxyapatite cement. , 1997, Journal of oral and maxillofacial surgery : official journal of the American Association of Oral and Maxillofacial Surgeons.

[8]  C. Snyderman,et al.  Hydroxyapatite cement to repair skull base defects: radiologic appearance. , 1996, AJNR. American journal of neuroradiology.

[9]  William A. Pierce,et al.  In vitro strength comparison of hydroxyapatite cement and polymethylmethacrylate in subchondral defects in caprine femora , 1998, Journal of orthopaedic research : official publication of the Orthopaedic Research Society.

[10]  A. Garg,et al.  The use of hydroxyapatite bone cement for sinus floor augmentation with simultaneous implant placement in the atrophic maxilla. A report of 10 cases. , 2000, Journal of periodontology.

[11]  E. Stelnicki,et al.  Hydroxyapatite Paste (BoneSource) Used as an Onlay Implant for Supraorbital and Malar Augmentation , 1997, The Journal of craniofacial surgery.

[12]  J. Klein-Nulend,et al.  Transforming growth factor-beta1 incorporation in a calcium phosphate bone cement: material properties and release characteristics. , 2002, Journal of biomedical materials research.

[13]  C. Friedman,et al.  Morphological and phase characterizations of retrieved calcium phosphate cement implants. , 2001, Journal of biomedical materials research.

[14]  E. Weibel.  Morphometry of the Human Lung , 1965, Springer Berlin Heidelberg.

[15]  Satish Govindaraj,et al.  Applications of Fast-Setting Hydroxyapatite Cement: Cranioplasty , 2000, Otolaryngology--head and neck surgery : official journal of American Academy of Otolaryngology-Head and Neck Surgery.

[16]  E. Fernández,et al.  Calcium phosphate bone cements for clinical applications. Part II: Precipitate formation during setting reactions , 1999, Journal of materials science. Materials in medicine.

[17]  R. Bennett,et al.  In vitro elution of gentamicin, amikacin, and ceftiofur from polymethylmethacrylate and hydroxyapatite cement. , 2000, Veterinary surgery : VS.

[18]  J A Planell,et al.  Osteotransductive bone cements , 1998, Proceedings of the Institution of Mechanical Engineers. Part H, Journal of engineering in medicine.

[19]  S. Best,et al.  Setting characteristics and mechanical behaviour of a calcium phosphate bone cement containing tetracycline. , 2001, Biomaterials.

[20]  C. Friedman,et al.  Hydroxyapatite cement. II. Obliteration and reconstruction of the cat frontal sinus. , 1991, Archives of otolaryngology--head & neck surgery.

[21]  C. Friedman,et al.  Hydroxyapatite cement. I. Basic chemistry and histologic properties. , 1991, Archives of otolaryngology--head & neck surgery.

[22]  C. Rey,et al.  Resorbable calcium phosphate bone substitute. , 1998, Journal of biomedical materials research.

[23]  B. Bai,et al.  The use of an injectable, biodegradable calcium phosphate bone substitute for the prophylactic augmentation of osteoporotic vertebrae and the management of vertebral compression fractures. , 1999, Spine.

[24]  H. Schliephake,et al.  Enhancement of bone regeneration using resorbable ceramics and a polymer-ceramic composite material. , 2001, Journal of biomedical materials research.

[25]  J. Torner,et al.  Comparison of the biomechanics of hydroxyapatite and polymethylmethacrylate vertebroplasty in a cadaveric spinal compression fracture model. , 2001, Journal of neurosurgery.

[26]  Susam Park,et al.  Umbilical reconstruction after repair of omphalocele and gastroschisis. , 1999 .

[27]  S. Belkoff,et al.  An Ex Vivo Biomechanical Evaluation of a Hydroxyapatite Cement for Use With Vertebroplasty , 2001, Spine.

[28]  R. Verheggen,et al.  Correction of Skull Defects Using Hydroxyapatite Cement (HAC) – Evidence Derived from Animal Experiments and Clinical Experience , 2001, Acta Neurochirurgica.

[29]  C. Snyderman,et al.  Hydroxyapatite: an alternative method of frontal sinus obliteration. , 2001, Otolaryngologic clinics of North America.

[30]  C. Lohse,et al.  Treatment of peri-implant defects with combination growth factor cement. , 2000, Journal of periodontology.

[31]  C. Friedman,et al.  Indications for hydroxyapatite cement reconstruction in lateral skull base surgery. , 1995, The American journal of otology.

[32]  C. Friedman,et al.  Sphenoethmoid cerebrospinal fluid leak repair with hydroxyapatite cement. , 2001, Archives of otolaryngology--head & neck surgery.

[33]  J A Planell,et al.  Addition of cohesion promotors to calcium phosphate cements. , 1999, Biomaterials.