Effect of degeneration on gene expression of chondrogenic and inflammatory marker genes of intervertebral disc cells: a preliminary study.

AIM: New techniques for biological repair in the treatment of degenerative disc disease (DDD) have been developed recently. The question arises whether it is possible to find a predictive marker to identify a patient population which could benefit from this new treatment option. Standard magnetic resonance imaging (MRI) fails to differentiate between pathologic painful and asymptomatic aging discs. Neurological symptoms contribute to identifying the pathological level. In this preliminary translational research study we analysed the gene expression of structure proteins and inflammatory mediators as well as histological features of lumbar intervertebral discs in symptomatic patients with various signs of degeneration in the MRI. METHODS: Specimens of intervertebral disc tissue were obtained from 20 patients undergoing lumbar nucleotomy. Preoperatively, a group selection based on four pre-defined MRI-criteria was performed: Group 1 (mild signs of degeneration), group 2 (moderate), group 3 (moderate-severe), group 4 (severe). RESULTS: An increase of the expression of structural proteins and inflammatory markers could be observed in MRI-groups 2 and 3. Gene expression of collagen type I and II and aggrecan went along with levels of cyclooxygenase-2 (COX-2) and (fibroblast growth factor-2) FGF-2 expression. Histological examination showed signs of granulation tissue in only 35% of cases, but no differences between the groups. CONCLUSION: Our findings implicate that the gene expression of structural proteins might correlate with the appearance of inflammatory mediators in symptomatic patients with moderate disc changes in the MRI in this preliminary clinical subset. The assessment of cell activity and protein expression in a larger number of patients could be next step to support and supplement the present data.

Cages with fixation wings versus cages plus plating for cervical reconstruction after corpectomy - is there any difference?

AIM: Different expandable and non-expandable fusion cages have gained acceptance in spinal surgery. We compared the radiological outcome of titanium cages with mounted wings to cages with additional anterior plating. METHODS: We performed a retrospective study of 44 patients after single or two-level cervical corpectomy. For reconstruction of the anterior column two different anterior distraction devices (ADD) were used: cage plus ventral plating (16 cases, ADD group) or cage with fixation wings (28 cases, ADDplus group). Clinical and radiological evaluations were performed after 1 week, 6 months and 12 months. Cervical lordosis, the angle between the adjacent vertebral bodies, the settling ratio, fusion rates, stability, neurological outcome and complications were assessed to compare both groups. RESULTS: Both groups had similar final clinical but different radiological outcomes. The fusion rate was 100% in the ADD group and 89% in the ADDplus group. Furthermore, the relative loss of cervical lordosis after 12 months was higher in the ADDplus group (-6.9% vs. -1.6%). The loss of correction of the relative rotation angle of the operated segment was also higher in the ADDplus group (-4.3 degrees vs. -1.7 degrees). Additional surgery was necessary in three cases in the ADDplus group. CONCLUSIONS: This study demonstrates that expandable cages are useful vertebral body replacements, because they can be adjusted to the size of the corpectomy in situ and provide immediate strong anterior column support avoiding bone graft site morbidity. The direct attachment of fixation wings to the cage simplifies the operative procedure but carries a significantly higher risk of non-fusion, loss of lordotic correction and height.

Human intervertebral disc-derived cells are recruited by human serum and form nucleus pulposus-like tissue upon stimulation with TGF-beta3 or hyaluronan in vitro.

The aims of this work were to test whether human intervertebral disc-derived nucleus pulposus cells (hNP-cells) are attracted by human serum and to analyze if matrix generation from hNP-cells is promoted under the influence of transforming growth factor-beta3 (TGF-beta3) or hyaluronan (HA) in vitro. Using the multi-well chemotaxis assay to determine cell migration under the influence of different concentrations of human serum, it was demonstrated that dedifferentiated hNP-cells are able to migrate towards a serum fraction gradient in a concentration-dependent manner. Re-differentiation capacity of hNP-cells in 3D micro-masses under the influence of TGF-beta3 or hyaluronan was also tested. Gene expression analysis of types I, II, III and IX collagen, as well as aggrecan, COMP and LINK of hNP-cells in 3D-micro-mass cell-culture revealed a strong increase of these markers in TGF-beta3 treated cells. Furthermore, histochemical and immuno-histochemical staining after 28d showed proteoglycan and type II collagen-rich matrix for both, the TGF-beta3 and the hyaluronan treated cells. These findings show that TGF-beta3 or hyaluronan are able to induce the differentiation and that human serum stimulates the migration of hNP-cells in vitro. Therefore, hyaluronan and serum are suited for cell-free biomaterials as cell migration and differentiation inducing factors intended for biological treatment strategies of the intervertebral disc.

Measurements of burr-hole localization for endoscopic procedures in the third ventricle in children.

OBJECTIVE: In a retrospective study, we measured the localization for the burr hole for neuroendoscopic procedures in the third ventricle, which are determined by anatomical landmarks like the foramen of Monro (FM) and the respective targets. PATIENTS AND METHODS: In 48 children, thin-sliced T2-weighted magnetic resonance images were analyzed within an imaging software tool to determine the trajectory between the FM to the floor of the third ventricle (F3V) or the entrance of the sylvian aqueduct (SA). The crossing point at the skull convexity defined the entry points. Coordinates are given relative to nasion and midline. A mean virtual entry point to reach both targets was compared to the burr-hole localization used in the respective surgeries. The tissue shift at the FM was quantified for the trajectories. RESULTS: The entry point to reach the F3V or the SA measured 119.7+/-26.4 mm (to nasion)-20.5+/-11.5 mm (to midline) and 57.4+/-26.5-18.8+/-8.3 mm, respectively. The virtual mean entry point to reach both targets was located at 86.5+/-25.3-20.9+/-9.8 mm. There was a statistical difference in the entry point localization relative to nasion of the virtual mean trajectory compared with the burr-hole localization used in these patients. The tissue shift at the level of the FM using the mean virtual trajectory was significantly lower than by using the actual burr hole to the SA. CONCLUSIONS: Planning an optimal burr-hole localization is important in neuroendoscopic procedures in children, especially where the target is located around the sylvian aqueduct.