Anatomical study of endoscope-assisted far lateral keyhole approach to the ventral craniocervical region with neuronavigational guidance

Background Image-guided neurosurgery, endoscopic-assisted neurosurgery and the keyhole approach are three important parts of minimally invasive neurosurgery and have played a significant role in treating skull base lesions. This study aimed to investigate the potential usefulness of coupling of the endoscope with the far lateral keyhole approach and image guidance at the ventral craniocervical junction in a cadaver model. Methods We simulated far lateral keyhole approach bilaterally in five cadaveric head specimens （10 cranial hemispheres）. Computed tomography-based image guidance was used for intraoperative navigation and for quantitative measurements. Skull base structures were observed using both an operating microscope and a rigid endoscope. The jugular tubercle and one-third of the occipital condyle were then drilled, and all specimens were observed under the microscope again. We measured and compared the exposure of the petroclivus area provided by the endoscope and by the operating microscope. Statistical analysis was performed by analysis of variance followed by the Student-Newman-Keuls test. Results With endoscope assistance and image guidance, it was possible to observe the deep ventral craniocervical junction structures through three nerve gaps （among facial-acoustical nerves and the lower cranial nerves） and structures normally obstructed by the jugular tubercle and occipital condyle in the far lateral keyhole approach. The surgical area exposed in the petroclival region was significantly improved using the 0° endoscope （1147.80 mm2） compared with the operating microscope （（756.28±50.73） mm2）. The far lateral retrocondylar keyhole approach, using both 0° and 30° endoscopes, provided an exposure area （（1147.80±159.57） mm2 and （1409.94±155.18） mm2, respectively） greater than that of the far lateral transcondylar transtubercular keyhole approach （（1066.26±165.06） mm2） （P 〈0.05）. Conclusions With the aid of the endoscope and image guidance, it is possible to approach the ventral craniocervical junction with the far lateral keyhole approach. The use of an angled-lens endoscope can significantly improve the exposure of the petroclival region without drilling the jugular tubercle and occipital condyle.

Coexistence of High Fibrinogen and Low High-density Lipoprotein Cholesterol Levels Predicts Recurrent Cerebral Venous Thrombosis

Background： Cerebral venous thrombosis （CVT） may lead to serious neurological disorders; however, little is known about the risk factors for recurrent CVT. Our aim was to determine the association between elevated fibrinogen and decreased high-density lipoprotein cholesterol （HDL-C） levels with recurrent CVT. Methods： This retrospective cohort study included participants if they had a first episode of objectively defined CVT and were admitted to Xuan Wu Hospital, Capital Medical University from August 2005 to September 2009. Demographic and clinical variables were collected, as well as laboratory parameters, inchiding plasma fibrinogen and HDL-C. Patients with CVT were tbllowed for recurrent symptomatic CVT. Follow-up was through the end of September 2010. Potential predictors of recurrence were analyzed using Cox survival analysis. Results： At tile end of the lbllow-up, 95 patients were eligible lbr the study. Twelve of 95 patients （12.6%） had recurred CVT. Tile median time of recurrence was 7 months （range： 1-39 months）. Eight of these 12 （66.7%） experienced rectirrence within the first 12 months alter their initial CVT. The recurrence rate of CVT was 2.76 per 100 patient-years. Multivariate Cox regression analysis demonstrated that the coexistence of high fibrinogen （〉4.00 g/L） and low HDL-C （〈1.08 mmol/L） levels at baseline was the only independent predictor for recurrent CVT （hazard ratio： 4.69; 95% confidence interval： 1.10-20,11; P 〈 0.05）. Of tile twelve patients with recurrent CVT in our study, 7 （58.3%） had high fibrinogen plus low HDL-C levels. All 7 of these patients took warfarin for 3-12 months, and 6 of 7 had rectirrent CVT after the discontinuation of anticoagulant treatment. Conclusions： Concomitant high fibrinogen and low HDL-C levels may be associated with recurrence of CVT. The ett＇ect of potential risk lhctors related to atherothrombosis on rectinent CVT should be closely monitored.

Low-intensity pulsed ultrasound prompts tissue-engineered bone formation after implantation surgery

Background A practical problem impeding clinical translation is the limited bone formation seen in artificial bone grafts.Low-pressure/vacuum seeding and dynamic culturing in bioreactors have led to a greater penetration into the scaffolds,enhanced production of bone marrow cells,and improved tissue-engineered bone formation.The goal of this study was to promote more extensive bone formation in the composites of porous ceramics and bone marrow stromal cells （BMSCs）.Methods BMSCs/β-tricalcium phosphate （β-TCP） composites were subcultured for 2 weeks and then subcutaneously implanted into syngeneic rats that were split into a low-intensity pulsed ultrasound （LIPUS） treatment group and a control group.These implants were harvested at 5,10,25,and 50 days after implantation.The samples were then biomechanically tested and analyzed for alkaline phosphate （ALP） activity and osteocalcin （OCN） content and were also observed by light microscopy.Results The levels of ALP activity and OCN content in the composites were significantly higher in the LIPUS group than in the control group.Histomorphometric analysis revealed a greater degree of soft tissue repair,increased blood flow,better angiogenesis,and more extensive bone formation in the LIPUS groups than in the controls.No significant difference in the compressive strength was found between the two groups.Conclusion LIPUS treatment appears to enhance bone formation and angiogenesis in the BMSCs/β3-TCP composites.