Bone regeneration of tibial segmental defect using isotropic-pore structures hydroxyapatite/alumina bi-layered scaffold: in vivo pilot study.

Bone defects resulting from trauma or pathology represent a common and significant clinical problem. In this study, hydroxyapatite (HAp)-alumina bi-layered scaffolds, which have the benefits of both HAp (i.e., osteointegration, osteoconduction) and alumina (i.e., hardness) were used as a bone substitute for the repair of large segmental defects (20 mm) created in a beagle tibia model. Highly porous bi-layered scaffolds with isotropic-pore structures were fabricated using a polymer-template coating technique. The pore sizes obtained using this approach ranged between 230 µm and 470 µm, and porosity was 91.61±1.28%. Using scanning electron microscopy and energy dispersive spectroscopy, it was confirmed that the frame of each bi-layered scaffold consisted of an alumina inner layer and HAp outer layer. The evaluation of bone regeneration within each scaffold after implantation in the beagle tibia was performed using CT, micro-CT, scintigraphy. New bone formation was evident in the large segmental defects treated with HAp/alumina scaffolds. It was concluded from this study that the HAp/alumina bi-layered scaffold is instrumental in inducing host-scaffold engraftment at the distal and proximal ends of the defect as well as distributing the newly formed bone throughout each scaffold 8 weeks post-implantation.

Clinical biology and surgical therapy of intramucosal adenocarcinoma of the esophagus.

BACKGROUND: Mucosal ablation and endoscopic mucosal resection have been proposed as alternatives to surgical resection as therapy for intramucosal adenocarcinoma (IMC) of the esophagus. Acceptance of these alternative therapies requires an understanding of the clinical biology of IMC and the results of surgical resection modified for treatment of early disease. STUDY DESIGN: Retrospective review of 78 patients (65 men, 13 women; median age 66 years) with IMC who were treated with progressively less-extensive surgical resections (ie, en bloc, transhiatal, and vagal-sparing esophagectomy) from 1987 to 2005. RESULTS: The tumor was located in a visible segment of Barrett's esophagus in 65 (83%) and in cardia intestinal metaplasia in 13 (17%). A visible lesion was present in 53 (68%) and in all but 4 the lesion was cancer. In those patients with visible Barrett's, the tumor was within 3 cm of the gastroesophageal junction in 66% and within 1 cm in 37%. Esophagectomy was en bloc in 23, transhiatal in 31, vagal-sparing in 20, and transthoracic in 4. Operative mortality was 2.6%. Vagal-sparing esophagectomy had less morbidity, a shorter hospital stay, and no mortality. Of the patients who had en bloc resection, a median of 41 nodes were removed. One patient had one lymph node metastasis on hematoxylin and eosin staining and two others, normal on hematoxylin and eosin staining, had micrometastases on immunohistochemistry. Actuarial survival at 5 years was 88% and was similar for all types of resections. Two patients died from systemic metastases and seven from noncancer causes. CONCLUSIONS: IMC occurred in cardia intestinal metaplasia and in Barrett's esophagus. Two-thirds of patients with IMC had a visible lesion. Most tumors occurred near the gastroesophageal junction. Node metastases were uncommon, questioning the need for lymphadenectomy. A vagal-sparing technique had less morbidity than other forms of resection and no mortality. Survival after all types of resection was similar. Outcomes of endoscopic techniques should be compared with this benchmark.