title: Tissue reactions to bioabsorbable ciprofloxacin-releasing polylactide-polyglycolide 80/20 screws in rabbits' cranial bone.
abstract: The aim of this study was to assess tissue reactions to bioabsorbable self-reinforced ciprofloxacin-releasing polylactide/polyglycolide (SR-PLGA) 80/20 screws in rabbits' cranial bone. Two screws were implanted in each rabbit, one screw on either side of the sagittal suture (n = 28 rabbits). Animals were sacrificed after 2, 4, 8, 16, 24, 54 and 72 weeks, four animals per group. On histological examination the number of macrophages, giant cells, active osteoblasts and fibrous tissue layers were assessed and degradation of the screws was evaluated. At 2 weeks, the highest number of macrophages and giant cells were seen near the heads of the screws. After 4 and 8 weeks, the number of giant cells decreased but that of macrophages decreased from 16 weeks and on. Screws were surrounded by fibrous tissue capsule that progressively was growing in thickness by time. Active osteoblasts were seen around the shaft of the screws with the highest number seen at 4 weeks postoperatively. At 16 weeks, compact fragmentation of the screw heads was seen with macrophages seen inside the screw matrices. After 24 weeks, no polarization of the screws was seen. After one year, PLGA screws had been replaced by adipose tissue, fibrous tissue and "foamy macrophages" which had PLGA particles inside them. After 1(1/2) years, the amount of biomaterial remaining had decreased remarkably. The particles of biomaterial were inside "foamy macrophages." Ciprofloxacin-releasing SR-PLGA 80/20 screws elicited a mild inflammatory reaction but did not interfere with osteoblast activity. No complications were seen when implanted in cranial bone of rabbit.
authors.affiliation: Department of Surgery, Oulu University Hospital, Oulu, Finland. jtiainen@cc.oulu.fi
authors.forename: Johanna
authors.initials: J
authors.lastname: Tiainen
authors.forename: Ylermi
authors.initials: Y
authors.lastname: Soini
authors.forename: Esa
authors.initials: E
authors.lastname: Suokas
authors.forename: Minna
authors.initials: M
authors.lastname: Veiranto
authors.forename: Pertti
authors.initials: P
authors.lastname: Törmälä
authors.forename: Timo
authors.initials: T
authors.lastname: Waris
authors.forename: Nureddin
authors.initials: N
authors.lastname: Ashammakhi
mesh_terms: D000818:Animals; D000890:Anti-Infective Agents / Q000008:administration & dosage* / Q000009:adverse effects; D001863:Bone Screws / Q000009:adverse effects*; D002939:Ciprofloxacin / Q000008:administration & dosage* / Q000009:adverse effects; D016503:Drug Delivery Systems / Q000009:adverse effects; D007249:Inflammation / Q000209:etiology / Q000473:pathology; D019344:Lactic Acid / Q000009:adverse effects; D008297:Male; D011100:Polyglycolic Acid / Q000009:adverse effects; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011108:Polymers / Q000009:adverse effects; D011817:Rabbits; D012886:Skull / Q000473:pathology* / Q000601:surgery*
chemical_list: D000890:Anti-Infective Agents; D011108:Polymers; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; D002939:Ciprofloxacin