The exact pathways of collagen remodeling in tendon tissue are not well understood. Therefore, we have established an ex vivo 3D collagen gel-based system and we studied the remodeling capacity of two different TSPC lines from young, Y-TSPC and aged/degenerative, A-TSPC donors. Here, we specifically focused on investigating the involvement of integrin receptors in the remodeling process. Integrins are transmembrane receptors consisting of alpha (a) and beta (b) subunits, which form cell-to-matrix bonds, activate various pathways and thereby control cell proliferation, differentiation and survival.

Y- and A-TSPC were derived from human Achilles tendons and are fully described in Kohler et al. 2013. RT-PCR was used to assess the expression of collagen-binding integrins in the TSPC cultivated in collagen gels. Next, a1 and a11 integrins were silenced by stable lentiviral delivery of target-specific shRNA in the Y-TSPC. Control (con-shRNA), integrin (a1-shRNA) and integrin a11 (a11-shRNA) virus-containing supernatant was given for 24h and then cells were selected with 50 microg./ml zeocin for 10 days. The integrin knockdown (KD) efficiency was assessed by quantitative PCR and western blotting. Last, functional tests were carried out by time-lapse recording gel contraction of four cell groups (Y-TSPC+con, Y-TSPC+a1KD, Y-TSPC+a11KD, and A-TSPC).

Among the screened integrins we found that integrin a1 and a11 were significantly downregulated in A-TSPC with 3.8 and 5.6 folds, correspondingly. Therefore, to mimic the A-TSPC we carried out a gene KD of a1 and a11 in Y-TSPC. PCR and western blot clearly validated the efficient KD. Analyses of collagen contraction, revealed that Y-TSPC+a11KD significantly reduced collagen contractability comparable to A-TSPC. This indicated the indispensable role of this integrin in the signaling pathway of collagen matrix remodeling. In respect to integrin a1, we found that this receptor did not affect the contraction rate of Y-TSPC, which was similar to Y-TSPC+con.

To our knowledge we have now identified for the first time the critical role of a11 integrin receptor in tendon collagen remodeling, and a follow up analysis of its exact downstream cascade is on the way. Future efforts in deciphering how tendon matrix makeover is regulated can lead to innovation in preventive strategies for tendon degeneration.

Ulnar styloid fractures may contribute to negative outcomes after distal radius fractures due to its association with distal radioulnar (DRUJ)instability and injuries of the triangular fibrocartilaginous (TFCC) complex. This study assesses clinical outcomes of untreated ulnar styloid fractures after internal fixation of distal radius fractures.

Patients undergoing operative fixation for distal radius fractures from January 2004 to June 2006 were divided into those with and without ulnar styloid fractures. The two groups were compared in terms of wrist range of motion, ulnar sided wrist pain, extensor carpi ulnaris (ECU) tendinitis, TFCC grind test, and DASH scores.

Thirty-one males and 23 females aged 50.9 years(18–88 yrs, SD 16.5) were assessed. At 24 months, the presence of ulnar styloid fractures had no impact on ulnar-sided wrist pain (p=0.331), TFCC grind test(p=0.917) and distal radioulnar joint instability (p=0.957). There was a tendency towards ECU tendinitis (23.8% vs 6.1%, p= 0.058) in patients with ulnar styloid fractures. There was no significant difference in the range of motion and overall DASH scores (8.0 vs 5.9, p=0.474).

No association was found between ulnar styloid fractures and DRUJ instability in this study. Ulnar styloid fractures behave like avulsion injuries. In the absence of DRUJ instability, conservative management of ulnar styloid fractures during operative treatment of distal radius fractures do not compromise clinical outcome.

Purpose: Effectively quantifying metastatic tumour involvement in the spine requires accurate vertebral segmentation. Automated techniques such as thresholding or region growing have difficulty defining boundaries between tumour tissue and surrounding soft tissue if lytic disease breaches the vertebral cortical shell. It is hypothesized that the application of image registration techniques may afford a potential solution to automating segmentation of metastically-involved vertebrae with cortical shell destruction. The objective of this study is to validate deformable registration as a means to automate the segmentation of tumour-bearing vertebrae through the transformation of atlas segmentations.

Methods: CT scans were collected from 6 patients (T4-L5) with spinal metastases secondary to breast cancer. Healthy levels from the patients were cropped and segmented using a combination of thresholding and manual delineation (Amira 3.1.1, TGS Berlin) to obtain the atlas for each vertebral level. After spatial alignment, metastatically involved vertebral levels were segmented by a registration of the atlas scan by automated affine registration (Amira) and refined by demons deformable registration (ITK, NLM Bethesda). The algorithm was tested through comparison of 10 vertebral bodies (thoracic and lumbar) segmented using the automated approach against a gold standard segmentation produced by semi-manual thresholding. The quality of the automatic segmentation was determined by calculating how many voxels were concurrently within both automatic and manual segmentation of the scan.

Results: Deformable registration successfully segmented metastatically involved vertebrae with and without breach of the cortical shell. Similar performance was evident when using an atlas from an adjacent level as compared to using an atlas of the identical vertebral level. Quality of the automatic segmentation ranged from 87.67%–96.22% concurrency. Comparisons of inter-user semi-manual segmentations yielded a similar maximum of 96% concurrency. Analysis speed was 10 to 15 times faster using the automated technique.

Conclusions: By maintaining the atlas morphology, atlas-based segmentations are able to accurately differentiate between trans-cortical tumours and surrounding soft tissue, overcoming problems inherent to more conventional automated segmentation techniques. Clinical application of this segmentation algorithm centers on tumour quantification and tracking progression of treatment effect and metastatic disease pathology. Funding: Other Education Grant Funding Parties: Canadian Breast Cancer Research Alliance, Sunnybrook & Women`s College Research Institute

Purpose: The objective of this study was to establish an automated and objective method to quantitatively characterize the extent, spatial distribution, and temporal progression of metastatic disease in the bony spine.

Methods: Serial patient CT scans from GE Light-speed Plus CT Scanners were standardized to 120kVp, 1.25mm/2.5mm slice interval/ thickness, standard reconstruction, and 0.468mm/0.468mm pixel spacing. From 3D reconstructed CT images, trabecular regions within vertebral bodies (VBs) were segmented through atlas-based deformable registration (ITK, NLM, Bethesda). Voxel intensity histograms (voxel counts vs. Hounsfield Units) were used to characterize 32 healthy and 11 metastatically involved vertebrae (T5 to L5). Healthy histograms were fitted to Gaussian regression curves and compared using one-way repeated measures ANOVA (p< 0.05). Tumours were segmented as connected areas with voxel intensities between specified thresholds (Amira 3.1.1, TGS, Berlin).

Results: Histograms of healthy vertebrae were found to be Gaussian distributions (avg. RMSD = 30 voxel counts). The Gaussian mean & #956; ranged from 120 to 290HU, presumably due to inter-patient differences in age and activity. However, the histogram data sets were not significantly different (p> 0.8) across intra-patient vertebral levels T5-L5. Consequently, the Gaussian parameters, & #956; and standard deviation & #963;, determined from fitted healthy histograms could be used in adjacent metastatic levels to define patient-specific lytic and blastic thresholds for tumor segmentation. The ideal lytic and blastic segmentation thresholds were determined to be & #956;−& #963; and & #956;+2& #963; respectively: i.e. while histograms of metastatic VBs were non-Gaussian (RMSD of 56 voxels), subtracting from them the tumourous regions segmented accordingly restored the Gaussian nature of the distributions (RMSD of 24 voxels). Metastatic involvement can then be quantified from histograms of metastases in terms of: (1) lytic/ blastic volumes from areas under the curves; (2) severity of the pathologic involvement from the distribution and range; (3) tumor progression over time or treatment effects by taking the difference between sequential scans.

Conclusions: This proposed histogram-based method for characterizing spinal metastases shows great potential in extending the quantitative capacity of CT-based radiographic evaluations, especially in tracking meta-static progression and treatment effectiveness in clinical research applications. Funding: Other Education Grant Funding Parties: NSERC and CBCRA

Purpose of study: To investigate the safety, efficacy, and feasibility of using high intensity focused ultrasound (HIFU) for the treatment of malignant bone tumors.

Methods: Forty-four patients with biopsy-proven malignant bone tumors were treated with HIFU (osteosarcoma: 32; chondrosarcoma: 3; periosteal osteosarcoma: 2; Ewing sarcoma: 1; other malignant bone tumor: 3, and unclassified tumor: 2). These tumors were situated as follows: distal femur – 20; proximal tibia – 7; mid-shaft of femur – 6; ilium – 2; shaft of fibula – 2; other – 4. HIFU was given as a noninvasive limb-salvage treatment in combination with neoadjuvant chemotherapy (methotrexate, adriamycin, cisplatin and ifosfamide) in thirty-four patients (Enneking’s Stage_b). Ten patients with stage IIIb (9 patients with lung metastasis) were treated with HIFU alone with palliative intent. The largest dimension of the tumors ranged from 5 to 46 cm. Postoperative biopsy, follow-up imaging (DSA, CT or MRI, and ECT), and functional evaluation were performed, and median survival time was calculated using the Kaplan-Meier method.

Results: Histopathological examination demonstrated clear evidence of tumor destruction and regrowth of normal bone in the treated region. When compared with baseline, follow-up imaging indicated complete coagulative necrosis of the treated tumors. Enneking’s functional scores were > 20, 15–20, and < 15 in 20, 14 and 5 cases respectively. Median follow-up was 23 months (range 10 to 40 months). Total survival rate was 85% (38/44). One patient with stage_b disease, and 5 patients with stage IIIb disease died as a result of distant metastases after HIFU treatment. 5 patients underwent amputation after local recurrence. Few complications were observed during follow-up. These were limited to 3 pathological fractures, 2 cases of peripheral nerve damage, restricted joint movement in 1 case, and epiphyseal separation in 1 case.

Conclusions: HIFU is safe, effective, and feasible in the treatment of patients with malignant bone tumors.