The response of subcutaneous connective tissue to newly developed calcium phosphate-based root canal sealers.

AIM: To evaluate the histopathologic biocompatibility of two new calcium phosphate-based sealers (CPS-1 & CPS-2) with a commercially available calcium hydroxide-based sealer (Acroseal). METHODOLOGY: Polyethylene tubes were filled with freshly mixed sealers and implanted subcutaneously in the dorsal connective tissue of rats. Empty tubes were used as controls. Histopathological examinations were conducted at 7, 15, 30, 60 and 90 days after the implantation procedure. The presence of inflammation and predominant cell types were analysed statistically with Mann-Whitney U and Kruskal-Wallis non-parametric tests. Fibrous connective tissue thickness adjacent to each sample was recorded. Differences were tested for significance using anova and 'Duncan's' multiple comparison test (P < 0.05). RESULTS: CPS-1 sealer was associated with severe inflammation and remained an irritation throughout the 90-day implantation period; the tissue reaction pattern was stromal fibrosis. The control, CPS-2 and Acroseal sealers had similar patterns of irritation, which were more severe initially and diminished with time creating a thin fibrous capsule around the implant with a complete absence of inflammatory cells. There was no difference in tissue reaction between the control, CPS-1, CPS-2 and Acroseal groups amongst the first two observation periods (P > 0.05). However, there was a highly significant difference between the same groups at the last two observation periods (P < 0.01). Also, there were highly significant differences between the observation periods within all four groups at 7, 15, 30, 60 and 90 days (P < 0.01). CONCLUSION: CPS-1 sealer was not biocompatible. CPS-2 sealer and Acroseal had a favourable biocompatibility level based on the histological findings.

Comparative study of biocompatibility of newly developed calcium phosphate-based root canal sealers on fibroblasts derived from primary human gingiva and a mouse L929 cell line.

AIM: To determine biocompatibility of three calcium phosphate cement (CPC) sealers, and to compare the cytotoxic response of human gingival fibroblasts (HGF) and one mouse fibroblast cell line (L929) to these materials. METHODOLOGY: Monocalcium phosphate, calcium oxide and synthetic hydroxyapatite were combined with one of three aqueous solutions: modified polyacrylic acid, glass-ionomer liquid or 35% w/w polymethyl vinyl ether maleic acid to obtain Types I, IIa and III CPCs, respectively. Commercial Ca(OH)(2) sealer was used as a control. The materials were packed into Teflon molds (5.5 x 3 mm), and cellular function was assessed using MTT assay. The specimens were placed immediately in contact with cells, then evaluated at (24 h, 1 week, 2 week, 3 week, 4 week, 5 week). RESULTS: All materials showed significant cytotoxicity for both L929 and HGF cells at 24 h except for Type III. Type I was severely toxic initially, but improved significantly (P < 0.05) over the 5 week evaluation. Types II and Ca(OH)(2) were both cytotoxic over the 5 weeks. Type III CPC was equivalent to Teflon the entire time. The results showed the same rank of cytotoxicity in both cultures. The cytotoxic response decreased in the order of Type II > Ca(OH)(2) > Type I > Type III overtime. L929 cells were generally more sensitive than HGF cells to the calcium hydroxide-based sealer (Acroseal). CONCLUSION: Types I and III have acceptable biologic properties for endodontic applications.

Evaluation of the cervical spine in the polytrauma patient.

STUDY DESIGN: Two-part study. Part One: the analysis of surveys distributed to members of the Orthopaedic Trauma Association (OTA) and 1000 surgeon members of NASS. Part Two: a prospective clinical study evaluating a new algorithm to evaluate the cervical spine in polytrauma patients. OBJECTIVES: To determine if there is a consensus of the optimal method for "clearing the cervical spine"; to assess the safety and efficacy of a newly proposed algorithm. SUMMARY OF BACKGROUND DATA: There is no uniformly accepted algorithm for "clearing the cervical spine" in the polytrauma patient or those patients with altered mental status secondary to the influence of alcohol, drugs or a closed head injury. METHODS: All members of the OTA and 1000 surgeon members of NASS were sent questionnaires to assess their methods of "clearing the cervical spine" in the polytrauma patient. Their answers were collated, analyzed and compared to standard ATLS protocol guidelines. A new protocol, which includes a surgeon, controlled stretch test and flouroscopically visualized flexion-extension views, was initiated and evaluated for safety and efficacy. SURVEY: Fifty-five percent of the members of the OTA and 31% of the NASS surgeons responded to the questionnaire. Among the responses from the NASS members, the ratio of orthopaedic spine surgeons to neurosurgeons accurately parallels the society's membership (77% ortho, 23% neuro). Sixty-nine of the OTA and 54% of the NASS responders replied that they followed ATLS guidelines. Analysis of their responses showed only 40% compliance. Eighty-one percent of the OTA respondents utilize the standard three view cervical spine trauma series, only 31% of the NASS members adhere to this guideline. Nearly 90% of all respondents identified the presence of neck pain or retropharygeal soft tissue swelling as an indicator to expand their initial radiographic evaluation. There was no consensus as to management of the polytrauma patient with a closed head injury. Eighty-two percent of all respondents has seen or treated a purely ligamentous injury of the c-spine. SPECTIVE STUDY: Prospective clinical protocol. 35-month period: enrolled 153 patients, 12,000 patients seen in trauma unit. Completed data 149/153. 8/153 unable to be cleared due to poor visualization of cervical-thoracic junction. 3/153 positive findings identified during fluoro examination. All three instability patterns verified in surgery (true positives). No untoward events to date. CONCLUSIONS: A standardized protocol to safely and effectively clear the cervical spine has yet to be established. Preliminary results of a new protocol to safely evaluate the cervical spine in the polytrauma patient are promising.

Video-assisted thoracoscopic surgery in the prone position.

STUDY DESIGN: Review of 27 consecutive patients who underwent video-assisted thoracoscopic surgery (VATS) in the prone position for anterior release and discectomy. OBJECTIVES: To convey the benefits and safety of this new technique for treating spinal deformities through VATS. SUMMARY OF BACKGROUND DATA: All reports using VATS for spinal deformities describe the patient in the lateral position. This is the first study to demonstrate the benefits and safety of the prone position. METHODS: The patient is positioned prone, prepared, and draped allowing room for lateral portals on the convexity of the curve. Traditionally, a double-lumen endotracheal tube is used to deflate the ipsilateral lung. Prone positioning eliminates this need, because gravity aids in retraction of the lung. RESULTS: All procedures were successfully performed using the VATS technique with the patient prone. After the anterior release and discectomy, posterior instrumentation (n = 27), costoplasty (n = 16), and fusion (n = 27) were performed. The time (n = 20) and blood loss (n = 16) for the anterior approach averaged 129 +/- 35 minutes and 221 +/- 231 mL, respectively. The mean number of disks resected was 3.3 +/- 0.7 (range, 2-5). CONCLUSION: The prone position is both safe and effective for VATS when treating spinal deformity. The current results confirm that there is no need to insert a double-lumen tube, there is gravity-assisted correction of kyphosis when the patient is prone, and significant operative time is saved with the elimination of repositioning and redraping before the posterior procedure. Surgical times and blood loss compare very favorably with those reported for VATS in the lateral position.