The biomechanical and histological effects of diabetes on tendon healing: experimental study in rats.

The aim of this study was to investigate the biomechanical and histological perspectives of healing of Achilles tendon in diabetic rats and compare the results with non-diabetic subjects. Fifty four adult Wistar Albino rats weighing 300-350 g were used throughout the study. Six animals were excluded from the study and replaced. Rats were randomly assigned to either the experimental or the control group comprised of 24 rats in each. Diabetes was induced in experimental group with streptozotocin. 3 days after the induction of diabetes, both Achilles tendons were transected 5 mm proximal to their insertions to the calcaneal bone and repaired by using 6/0 polypropylene sutures with modified Kessler method. At weeks 2, 4 and 6, eight rats from each group were euthanized. Left Achilles tendons including the repair site were prepared for histological evaluation and right legs were prepared for mechanical testing. When compared to control group, diabetic animals displayed a lower peak force for failure in each of the second, fourth and sixth week. The differences between the groups in each week were found to be significant in statistical assessments (p < 0.05). Histologic assessment revealed that the diabetic animals had significantly less amount of fibroblast proliferation and lymphocyte infiltration compared to the control group. There is significant delay in tendon strength at the end of week 2, 4 and 6 postoperatively in the diabetic rats. Therefore diabetic individuals require specific postoperative follow up and rehabilitation procedures.

Bone flap prefabrication: an experimental study in rabbits.

The usual method to prefabricate a bone flap is to harvest a nonvascularized bone graft and to implant the artery and vein bundle between segments of bone graft. The basic problem of this method is sacrificing an artery for prefabrication. Another method for creating flap donor sites without using an artery is venous flap prefabrication. There are a few articles describing bone flap prefabrication, and these include implantation of both artery and vein as a vascular bundle. Also, there is no experimental study in the literature using a vein or an arterialized vein pedicle for bone flap prefabrication. As an experimental model for bone flap prefabrication, the rabbit ear vascular model was chosen. For the experiments 3 groups were formed. Each group contained 5 rabbits. In the first experimental group a vein was implanted between the halves of bone graft. In the second experimental group an arterialized vein was implanted between the halves of bone graft. To compare the viability of the bone graft of the 2 prefabrication groups, a bone graft was implanted into the subcutaneous pocket of the posterior auricular area in the third group. The authors examined 5 rabbits in each group by microangiography at the end of 6 weeks except for group 3. On microangiographic analysis, groups 1 and 2 showed patency of the vascular pedicle. There was no difference between these 2 groups from the point of view of vascular patency and bone appearance. Bone scintigraphy was performed for 5 rabbits in each group. On bone scintigraphic scans, the bone component of the flaps was visualized in groups 1 and 2, but not in group 3. A quantitative analysis of images was performed by drawing symmetric spherical regions of interest (ROIs) over both the implanted area and cranial bone. The uptake ratios were computed by dividing the mean counts in the implanted ROI by mean counts in the cranial bone ROI. The mean value was 0.86 +/- 0.02 in group 1 and 0.86 +/- 0.04 in group 2. A statistically significant uptake difference was not seen between venous and arterialized venous groups (P < 0.01). Histologic examination was performed all rabbits in each group, and demonstrated that the bony component was viable, showing osteocytes containing lacunae, osteoblasts along bony trabeculae, and vascular channels in groups 1 and 2. In group 3, the bony architecture of the graft was still apparent, but all bone within it was dead. There were no significant microangiographic, histologic, and scintigraphic differences between the 2 experimental methods.

Evaluation of maxillary sinus after treatment of midfacial fractures.

PURPOSE: Maxillary sinuses are the most frequently injured anatomic region of the facial skeleton in midfacial fractures. The purpose of this study was to evaluate the patients with maxillary sinus wall fractures using clinical examinations, maxillofacial computed tomography (CT), and cranial bone single-photon emission tomography (SPECT) and to interpret the results of these examinations to evaluate the indications of surgical intervention or drainage for maxillary sinus after maxillary sinus wall fractures. MATERIALS AND METHODS: The results of examinations of 15 patients with maxillary sinus fractures who were treated for midfacial fractures were evaluated. Follow-up examinations were performed in the range of 3 to 47 months after surgery (average, 19.8 months). The patients ranged in age from 10 to 45 years, with an average age of 31.6 years. There were 11 male and 4 female patients. Seven patients had Le Fort II fractures, 6 patients had tripod zygomatic fractures, 1 patient had infraorbital fracture, and 1 patient had zygomatic arch fracture. Operative procedure was performed in all cases. To evaluate maxillary sinus after surgery, maxillofacial computed tomography (CT), cranial bone SPECT, and maxillary sinusitis evaluation form were used in all patients. RESULTS: Maxillofacial CT scans were related to sinusitis in 9 patients who had positive complaints for sinusitis. The cranial bone SPECT showed positive uptake at the fractured sites in 8 patients, minimal uptake in 2 patients, and normal uptake in 5 patients. CONCLUSIONS: Clinical examination, maxillofacial CT, and cranial bone SPECT are the most reliable methods available today for the diagnosis and follow-up of complications of maxillary sinus fractures.