Histocytochemistry of glycoconjugates in nasal inverted papilloma

Assessment of biphasic calcium phosphate to repair nasal septum defects in sheep

BACKGROUND

Saddle nose and septal perforations are among the most surgically challenging situations in nasal reconstruction. They require a significant volume of autologous graft and a complex surgical procedure. The aim of this study was to evaluate the biocompatibility of the biphasic calcium phosphate implant in the nasal septum and its ability to replace septal skeleton with unilateral or bilateral exposure.

METHODS

Thirty sheep underwent anterior nasal septum perforation. Only 20 septa were repaired with the implant exposed to nasal content on bilateral (group 2) and unilateral (group 3) sides. After 45 days of spontaneous cicatrization, the surface of new airway mucosa covering implants and the amount of closure were evaluated macroscopically. Light microscopy, histomorphometry, immunohistochemistry, and transmission electron microscopy were performed to assess soft-tissue growth and differentiation. Statistical analysis was performed by means of the Mann-Whitney test.

RESULTS

The mean rate of mucoperichondrial flap recovery of the implant was 66 percent in group 2 and 82 percent in group 3, and was significantly different from that of the control group (p < 10(-4)). The mean amount of closure was 32 and 64 percent, respectively (p < 10(-3)). The thickness of the perichondrium was greater than the control on both sides (p < 10(-4)). Vascularized soft tissues and bone formation invaded pores of implants. No pathologic inflammation was observed in submucosa. Moderately differentiated and well differentiated newly formed epithelium were the most frequent types observed, with good correlation between immunostaining and morphologic features.

CONCLUSION

These data suggest a good biocompatibility of biphasic calcium phosphate and its ability to repair the nasal septum in sheep.

Biphasic calcium phosphate to repair nasal septum: the first in vitro and in vivo study

Our objective was to evaluate the cytocompatibility and biocompatibility of biphasic calcium phosphate (BCP) in the nasal respiratory airway. In vitro, the attachment rate was quantified on BCP disks with normal human epithelial cells at 1, 3 and 24 h by determining N-acetyl beta-D-hexosaminidase activity. Proliferative activity of cells was indirectly assessed by MTT assay at 3, 9, 15 and 21 days. Plastic surfaces were used as positive control. In vivo, 15 rabbits underwent anterior nasal septum perforation and 10 septa were repaired with BCP disks. Five non-implanted animals were sacrificed at 3 months. Two groups of five implanted animals were sacrificed at 1 and 2 months. The surface of new airway mucosa covering BCP disks was evaluated macroscopically. During both steps, light microscopy, immunohistochemistry and scanning electron microscopy were performed. Statistical analysis was performed with the Mann-Whitney U-test. In vitro, at 1 and 3 h, the attachment rates were significantly better than on the plastic surface (p < 10(-2)). Mitochondrial activity increased on both surfaces but began 6 days later than on plastic. After 21 days of culture, cells were confluent and formed a monolayer covering the implant even in the bottom of the pores. In vivo, no perforations in the control group closed spontaneously. The mean rate of closure was 63% in the 1 month group and 64% in the 2 month group (p > 0.05). Implants were invaded by inflammatory reaction covered by incomplete differentiated respiratory epithelium. Throughout the study, all immunohistochemical findings remained positive. These data suggest a good affinity between BCP and nasal epithelial cells. BCP could be used to rebuild nasal septa.