Validation and accuracy of intraoperative CT scan using the Philips AlluraXper FD20 angiography suite for assessment of spinal instrumentation.

BACKGROUND: With the concept of the hybrid operating room gaining popularity, the authors adapted a hybrid angiographic suite with intraoperative computed tomography (iCT) to evaluate accuracy of pedicle screw placement in spinal fusion. This retrospective review examines how well iCT detected extrapedicular screw violation, to then allow repositioning and potentially avoid revision surgery. METHODS: A total of 36 consecutive patients underwent pedicle screw placement in posterior cervical, thoracic, and lumbosacral spinal fusions. All patients underwent iCT in the Philips AlluraXper FD20 angiography suite in the lumbar spine XperCT mode and postoperative conventional computed tomography (CT) scanning. Primary endpoints included the sensitivity and specificity of iCT in detecting pedicular violation characterized as minor, moderate, or severe when compared with postoperative CT. Secondary endpoint included the incidence of replaced screws during surgery and number of revision surgeries. RESULTS: Of 241 screws placed in 16 males and 20 females, iCT detected severe pedicle violation in 25 screws (10.4%); 16 screws were then repositioned during surgery. Sensitivity and specificity of iCT to detect severe screw malposition were 92.3% and 99.1%, respectively. No revision surgeries were performed in this series. CONCLUSIONS: In our series, iCT had high sensitivity and specificity in detecting severe screw malposition. As a valuable adjunct for intraoperative assessment of pedicle screw position, immediate intraoperative correction of misplaced screws then eliminated any revision surgery for our patients.

Expression of trefoil factor 1 in the developing and adult rat ventral mesencephalon.

Trefoil factor 1 (TFF1) belongs to a family of secreted peptides with a characteristic tree-looped trefoil structure. TFFs are mainly expressed in the gastrointestinal tract where they play a critical role in the function of the mucosal barrier. TFF1 has been suggested as a neuropeptide, but not much is known about its expression and function in the central nervous system. We investigated the expression of TFF1 in the developing and adult rat midbrain. In the adult ventral mesencephalon, TFF1-immunoreactive (-ir) cells were predominantly found in the substantia nigra pars compacta (SNc), the ventral tegmental area (VTA) and in periaqueductal areas. While around 90% of the TFF1-ir cells in the SNc co-expressed tyrosine hydroxylase (TH), only a subpopulation of the TH-ir neurons expressed TFF1. Some TFF1-ir cells in the SNc co-expressed the calcium-binding proteins calbindin or calretinin and nearly all were NeuN-ir confirming a neuronal phenotype, which was supported by lack of co-localization with the astroglial marker glial fibrillary acidic protein (GFAP). Interestingly, at postnatal (P) day 7 and P14, a significantly higher proportion of TH-ir neurons in the SNc co-expressed TFF1 as compared to P21. In contrast, the proportion of TFF1-ir cells expressing TH remained unchanged during postnatal development. Furthermore, significantly more TH-ir neurons expressed TFF1 in the SNc, compared to the VTA at all four time-points investigated. Injection of the tracer fluorogold into the striatum of adult rats resulted in retrograde labeling of several TFF1 expressing cells in the SNc showing that a significant fraction of the TFF1-ir cells were projection neurons. This was also reflected by unilateral loss of TFF1-ir cells in SNc of 6-hydroxylase-lesioned hemiparkinsonian rats. In conclusion, we show for the first time that distinct subpopulations of midbrain dopaminergic neurons express TFF1, and that this expression pattern is altered in a rat model of Parkinson's disease.