Safe Zone of Posterior Screw Insertion for Talar Neck Fractures on 3-Dimensional Reconstruction Model.

OBJECTIVE: To investigate the optimal posterior screw placement and the geometry of safe zones for screw insertion in the talar neck. METHODS: Computed tomography data for 15 normal feet were imported into Mimics 10.01 software for 3-dimensional reconstruction; 4.0-mm-diameter screws were simulated from the lateral tubercle of the posterior process of the talus to the talar head. The range of screw paths trajectories and screw lengths at nine locations that did not breach the cortex of the talus were evaluated. In addition, the farthest (point a) and nearest point (point b) of the safe zone to the subtalar joint at each location, the anteversion angle (angle A), which is parallel to the sagittal plane, and the horizontal angle (angle B), which is perpendicular to the sagittal plane, were measured. RESULTS: The safe zone was mainly between the 30% location and the 60% location; the width of each safe zone was 13.6° ± 1.4°; the maximum height of each safe zone was 7.8° ± 1.2°. The height of the safe zone was lowest at the 30% location (4.5°) and highest at the 50% location (7.3°). The mixed safe zone of all tali was between the 50% location and the 60% location. When a screw was inserted at point a, the safe entry distance (screw length) ranged from 48.8 to 49.5 mm, and when inserted to point b, the distance ranged from 48.2 to 48.9 mm. And inserting a 48.7 mm screw, 5.6° laterally and 7.4° superiorly, from the lateral tubercle of the posterior process of the talus towards the talar head is safest. CONCLUSION: The safe zone of posterior screw fixation have been defined applying to most talus, assuming the fractures are well reduced, this may strengthen the stability, shorten the operation time and reduce the incidence of surgical complications.

Neuropeptide Y stimulates osteoblastic differentiation and VEGF expression of bone marrow mesenchymal stem cells related to canonical Wnt signaling activating in vitro.

Neuropeptide Y (NPY) is a neuropeptide secreted by sensory nerve fibers distributed in the marrow and vascular canals of bone tissue. However, the effect of NPY on the osteogenic ability of bone marrow mesenchymal stem cells (BMSCs) remains controversial and has not been thoroughly investigated. To explore the osteogenic activity and the migration and VEGF expression capabilities of BMSCs affected by NPY, as well as the underlying mechanisms, we investigated the potential relationships among NPY, osteoblastic differentiation, angiogenesis and canonical Wnt signaling in BMSCs. NPY was observed to regulate osteoblastic differentiation at concentrations ranging from 10(-8) to 10(-12)mol/L, and the effects of NPY on the levels of Wnt signaling proteins were detected using Western blotting. To unravel the underlying mechanism, BMSCs were treated with NPY after pretreatment with the NPY-1R antagonist PD160170 or the Wnt pathway antagonist DKK1, and gene expression levels of Wnt signaling molecules and osteoblastic markers were determined by qPCR. Our results indicated that NPY significantly promoted osteoblastic differentiation of BMSCs in a concentration-dependent manner and up-regulated the expression levels of proteins including ß-catenin and p-GSK-3ß and the mRNA level of ß-catenin. Moreover, NPY promoted the translocation of ß-catenin into nucleus. The effects of NPY were inhibited by PD160170 or DKK1. Additionally, NPY enhanced the ability of BMSCs to migrate and promoted the expression of vascular endothelial growth factor (VEGF) as measured by immunocytochemical staining, qPCR and Western blot. These results suggested that NPY may stimulate osteoblastic differentiation via activating canonical Wnt signaling and enhance the angiogenic capacity of BMSCs.

Advantages of laparoscopic abdominoperineal resection for anastomotic recurrence of rectal cancer.

BACKGROUND: Surgery offers the only potential for cure and long-term survival of recurrence of rectal cancer. Few studies about laparoscopic recurrent lesion resection have been reported. This study was designed to evaluate the safety and feasibility of laparoscopic abdomino-perineal resection for anastomotic recurrence of rectal cancer. MATERIALS AND METHODS: Data for 42 patients with recurrence of rectal cancer were collected retrospectively. Of the 42 patients, 22 underwent laparoscopic surgery (LR group) and 20 received open surgery (OR group). Outcomes between the two groups were compared. RESULTS: Operation time in LR group was shorter compared with the OR group (164.6 ± 27.7 min vs 203.0 ± 45.3 min); intra-operative blood loss was 119.7 ± 44.4 ml and 185.0 ± 94.0 ml in LR group and OR group, respectively (p<0.001); time to first flatus in LR group was shorter than in OR group, and the difference was statistically significant (2.6 ± 0.8 days vs 3.1 ± 0.8 days, p=0.013); hospital stay in the LR and OR groups was 8.6 ± 1.3 days and 9.8 ± 2.2 days; 3-year survival rates in the LR and OR groups were 44.4% and 42.8% (p=0.915) and the 3-year disease-free survival rates were 36.4% and 30.0%, respectively (p=0.737). CONCLUSIONS: Laparoscopic abdomino-perineal resection is safe and feasible for anastomotic recurrence of rectal cancer.

Intra-operative perforation: a risk factor for prognosis of low rectal cancer after abdominoperineal resection.

This study was designed to explore the influence of intra-operative perforation on prognosis of low rectal cancer after APR and to investigate the risk factors of perforation. Perforation is not scarce during the procedure of abdominoperineal resection (APR). There is no consensus on perforation rate and related risk factor for APR. Data of 925 patients who received APR for low rectal cancer between January 2000 and August 2008 were reviewed. The intra-operative perforation rate was 7.4 % (68/925). The recurrence rate was 28.6 % in patients with intra-operative perforation compared with 6.8 % in patients with no perforation (P < 0.001); 5-year survival rate in patients with perforation was 41.4 and 66.3 % in patients with no perforation. Univariate analysis showed that intra-operative perforation affected recurrence rate and survival significantly (P < 0.001, P < 0.001); multivariate analysis revealed that intra-operative perforation was an independent prognostic factors for recurrence (RR: 3.087, P < 0.001), while not for survival (RR: 1.331, P = 0.051). Patients aged more than 70 years, T3 tumor and treated by general surgeon had higher perforation rate (P = 0.001, P = 0.004, P = 0.008). Intra-operative perforation affected the prognosis of low rectal cancer after APR significantly. Elderly patient aged more than 70 years, T3 tumor and general surgeon who performed operation were three risk factors of increased perforation rate.