Effects of a dexamethasone-releasing stent on osteoneogenesis in a rabbit model.

BACKGROUND: This study is an evaluation of wound healing in an animal model for surgery of frontal sinusitis and treatment effect of topically released dexamethasone using a drug-releasing stent with special emphasis of osteoneogenesis. METHODS: A prospective, controlled, randomized, double-blinded animal study was performed. Nineteen New Zealand white rabbits were subjected to surgery via an external approach, a 4-mm circular wound was created on the medial side of the maxillary sinus and the underlying bone was denuded of periosteum. The wound was covered in a randomized fashion with either a silicone foil or a new dexamethasone-releasing stent system. Twelve to 30 days later, the animals were killed and a histological examination was performed. RESULTS: In comparison with the baseline bony thickness (40 micrometer) obtained in one animal, osteoneogenesis occurred on both paranasal sides but was significantly less if a dexamethasone-releasing stent was applied (117 [95% CI, 116-128]; 52 [95% CI, 43-64]; p < 0.001). Maximal bony thickness was observed in both treatment groups between days 20 and 25 with a tendency toward a higher percentage decrease in the dexamethasone-treated sides (p < 0.08). Using a visual analog scale (0-5) a significantly smoother bony surface was observed for dexamethasone (2 [95% CI, 1.1-1.9]; 2 [95% CI, 1.8-2.2]; p < 0.01). CONCLUSION: Using a new drug-releasing stent system, dexamethasone efficiently decreases postoperative osteoneogenesis in a standardized animal wound model for endoscopic sinus surgery. Therefore, the use of this system may be of value to decrease restenosis rates using corticosteroids in selected patients after frontal sinus surgery, especially the endoscopic modified Lothrop procedure.

Effects of topically applied dexamethasone on mucosal wound healing using a drug-releasing stent.

OBJECTIVE/HYPOTHESIS: Evaluation of the impact of continuously topically released dexamethasone using a drug-releasing stent on quality of regenerated mucosa after full thickness injury in the paranasal sinuses. STUDY DESIGN: Prospective, controlled, randomized, double-blinded animal study. METHODS: Nineteen New Zealand white rabbits were subjected to surgery: via an external approach, a 4 mm circular wound was created on the medial side of the maxillary sinus. The wound was covered in a randomized fashion with either a silicone foil or a new drug releasing stent system. Twelve to 30 days later, the animals were killed and histology and electron microscopy were performed. One animal was used for baseline comparisons at day 0. RESULTS: No animals were lost due to infection or dislocation of the stent, leaving 18 animals for evaluation of postoperative healing quality. According to macroscopic examination, extent of granulations was smaller in the treatment group (dexamethasone: median 0 [95% confidence interval: 0.1-0.6]) than the silicone group (2 [1.5-2.3]; P < or = .05). Epithelial wound healing was complete in all specimens, whereas the stroma was significantly thinner in the dexamethasone-group (44 [37-60]; 178 [148-214]). Improved healing quality was achieved significantly more often on the treatment, than on the control side. Scanning electron microscopy revealed no difference between both groups. CONCLUSIONS: Using a new drug-releasing stent system, dexamethasone efficiently decreases granulation formation and stroma thickness without impeding epithelial differentiation. Therefore, the use of this system may be of value to decrease restenosis rates in selected patients after frontal sinus surgery.

Standardized video-endoscopy and surgical field grading scale for endoscopic sinus surgery: a multi-centre study.

BACKGROUND: Bleeding is a major concern in endoscopic sinus surgery (ESS), as it may impede surgical progress and is often associated with complications. To improve the study and management of intraoperative bleeding, a standardized method of recording bleeding during ESS is needed. The aim of this study was to develop a standardized method of documenting bleeding in ESS and of grading the surgical field. METHODS: Bleeding after endoscopic sinus surgery was recorded using video-endoscopy. Standardized and non-standardized video-endoscopies of 20 patients were graded using a previously published grading scale (the Boezaart scale) in randomized order on two different occasions. Effects of standardization on intra- and interrater reliability were evaluated.Based on this experience, a new 11-point surgical field grading scale was developed and simultaneously compared with the six-point Boezaart scale via means of a DVD in three international centers. RESULTS: Inter and intrarater reliability of the Boezaart and new Wormald scales significantly improved by employing a standardized video-endoscopy technique. The Wormald scale had significantly higher interrater (0.80 vs. 0.74, P < .001) and intrarater (0.89 vs. 0.83, P < .001) reliability than the Boezaart scale. Linear regression analysis revealed the Wormald scale to be more sensitive to changes in the most common surgical fields experienced in ESS. CONCLUSION: Standardized video-endoscopy has been demonstrated to significantly improve reliability and reproducibility of results and is recommended for future work evaluating bleeding in ESS. The new Wormald grading scale has been shown to be an inexpensive, reliable, and sensitive tool to rapidly evaluate intraoperative bleeding in ESS. It overcomes several limitations of the Boezaart scale, enabling us to analyze currently employed and newly developed hemostatic methods and agents.

Early elevation of S-100B protein in blood after cardiac surgery is not a predictor of ischemic cerebral injury.

BACKGROUND: We hypothesized that early changes in S-100B levels after cardiac surgery are nonspecific and mostly reflect damage to tissues outside the brain rather than ischemic brain damage. METHODS: We measured serum levels of S-100B at several times perioperatively in 21 patients undergoing cardiac surgery. In addition, we measured levels of neuron specific enolase (NSE), glial fibrillary acidic protein (GFAP), creatine kinase (CK), the cardiac isoenzyme of CK (CK-MB), and myoglobin (MB) in these patients. RESULTS: Early increases in serum S-100B concentration were significantly (p<0.01) correlated with increases in markers of tissue injury outside the brain: S-100B/CK: r(2)=0.69; S-100B/CK-MB: r(2)=0.64; S-100B/myoglobin: r(2)=0.60; S-100B/NSE: r(2)=0.51; CK/NSE: r(2)=0.60; CK-MB/NSE: r(2)=0.59; and myoglobin/NSE: r(2)=0.54. CONCLUSIONS: Our findings indicate that increases in S-100B in the early phase after cardiac surgery are not due to release of S-100B from brain alone but also from tissue outside the brain.