title: In vivo preclinical evaluation of the influence of osteoporosis on the anchorage of different pedicle screw designs.
abstract: We investigate the anchorage of pedicle screws with different surface treatments in osteoporotic bone. Eight ewes were divided into two groups of four animals each: four sheep underwent bilateral ovariectomy (OVX Group), whereas the operation was simulated in the remaining group (SHAM Group). Eighteen months after the first operation, the Dynesys(®) System was fitted to the sheep using pedicle screws with three different surface treatments: untreated, rough blasted (uncoated) and bioactive coated (bioactive). Uncoated screws showed a significantly higher bone ingrowth value compared with the untreated screws in the OVX group (9.3%, p < 0.005) and a significantly lower bone ingrowth value in the SHAM group (-11.0%, p < 0.05). Furthermore, the bioactive pedicle screws had a significant lower bone ingrowth value than the untreated screws in the SHAM group (-12.1%, p < 0.05). These results suggest that both tested surface treatments of pedicular screws may provide an advantage in terms of bone quality and osseointegration, when implanted in osteoporotic vertebrae.
authors.affiliation: Laboratory of Preclinical and Surgical Studies, Istituto Ortopedico Rizzoli, Via di Barbiano 1/10, 40136 Bologna, Italy. gianluca.giavaresi@ior.it
authors.forename: Gianluca
authors.initials: G
authors.lastname: Giavaresi
authors.forename: Milena
authors.initials: M
authors.lastname: Fini
authors.forename: Roberto
authors.initials: R
authors.lastname: Giardino
authors.forename: Francesca
authors.initials: F
authors.lastname: Salamanna
authors.forename: Maria
authors.initials: M
authors.lastname: Sartori
authors.forename: Veronica
authors.initials: V
authors.lastname: Borsari
authors.forename: Silvia
authors.initials: S
authors.lastname: Spriano
authors.forename: Chiara M
authors.initials: CM
authors.lastname: Bellini
authors.forename: Marco
authors.initials: M
authors.lastname: Brayda-Bruno
mesh_terms: D000818:Animals; D001863:Bone Screws / Q000592:standards*; D004195:Disease Models, Animal; D004867:Equipment Design / Q000379:methods; D005260:Female; D016348:Osseointegration / Q000502:physiology*; D058866:Osteoporotic Fractures / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery*; D011859:Radiography; D034561:Sheep, Domestic; D016103:Spinal Fractures / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery*; D013123:Spinal Fusion / Q000295:instrumentation* / Q000379:methods