Summary of Background Data. C2 intralaminar screws offer the advantages of avoiding the vertebral artery; however, direct biomechanical comparison of this technique to the other methods of instrumenting
C2 has not been performed.
Methods. Fourteen cadaveric specimens were dual energy radiograph absorptiometry scanned and segregated into 2 groups (n = 7/group) matching Sonidegib purchase the C2 bone mineral density. All specimens were instrumented with C1 lateral mass and C2 intralaminar screws while measuring the insertional torque (IT). In group 1 C2 pars screws were inserted while in group 2 pedicle screws were placed. Nondestructive testing was performed in axial rotation, flexion/extension (FE), and PRIMA-1MET lateral bending. The odontoid was then resected and loading repeated. Subsequently, specimens were disarticulated about C2 and individually loaded for 2000 cycles in the cephalocaudad plane. The screws were then failed by a tensile load directed in the parasagittal plane. Full range of motion over C1-C2 and peak screw pull-out force was quantified.
Results. Transpedicular technique generated significantly higher IT than the pars screws and marginally greater IT than intralaminar screws. With the intact atlantoaxial ligamentous complex, intralaminar fixation was superior to pars and similar to pedicle instrumentation at limiting axial torsion. After odontoid destabilization, however, this technique
was less effective at reducing the lateral bending range of motion. Destructive loading revealed the highest pull-out forces with the pedicle screws, followed by intralaminar and pars screws.
Conclusion. Our results suggest that C2 intralaminar fixation provides a viable alternative to pedicle screws and is superior to pars instrumentation in cases with preserved atlantoaxial ligamentous attachments. In the presence of a traumatic dens fracture, however, intralaminar fixation may not be the optimal choice.”
“Purpose of review
There are more than 250 transplant Baf-A1 concentration centers in the USA, but variation continues to exist in organizational
structure for transplant multidisciplinary services. We reviewed the literature to explore the definitions for transplant organizational structures and address existing rationale for the development of the integrated transplant service line.
Recent findings
No standard definitions exist to differentiate the use of program, center, institute, or service line. A survey of 20 multiorgan transplant centers in the USA showed that most were named centers or institutes, but some were organized as departments and service lines. The prevailing themes were the perceived need for autonomy of the transplant entity, alignment among services and finances, and the alignment of authority with responsibility. In addition, perceived benefits included growth, alignment, efficiency, and resource allocation.