CT Fusion Research Articles

Двухлетние результаты хирургического лечения переломов позвоночника с применением углеродных имплантатов (мультицентровое исследование)

Introduction A good alternative to bone autograft fusion is the utilization of implants produced from non-biological materials. Such implants can reduce the duration of surgery as well as tissue morbidity, while meeting the mechanical strength and osteoconductivity requirements. According to the study results,carbon is a promising material for interbody fusion because of its biocompatibility and osseointegration, as well as an elastic modulus that is close to bone tissue. Methods From 2015 to 2017 a randomized multicenter study was conducted. Three centers took part in the study: the National Medical Research Center of Traumatology and Orthopedics named after N.N. Priorov; Novosibirsk Research Institute for Traumatology and Orthopedics named after Ya.L. Tsivyan; Saint-Petersburg National Phtisiopulmonology Research Institute. One hundred thirteen patients with vertebral body fractures were included in the study and underwent surgical treatment using posterior interbody fusion. In 75 patients (66.37 %, group I) carbon-carbon implants were used, and in 38 patients (group II) – titanium cages. Patient examination was conducted using one protocol, preoperative examination methods and at 6, 12, and 24 month follow-ups, and included VAS score, SF-36 questionnaire, and ASIA scale, as well as CT examination and fusion progress assessment according to G. Tan’s classification. Results The 2-year study showed statistically significant differences between index (carbon implants) and control (titanium cages) groups. Although bone fusion progressed very slowly in the study group (in 86 % of cases no bone fusion was observed at first follow-up 6 months after surgery), the VAS and SF-36 scores were comparable in study and control groups. Discussion Carbon implants are characterized not only by high mechanical strength but also by a significant ability to osteoconductivity that allow for effective bone-carbon fusion due to their porous structure and an elastic modulus of 20–30 GPa, that is comparable to that of bone tissue. These characteristics were confirmed by radiological data (absence of implant subsidence in 38 out of 58 patients (65.51 %) at 24 month follow-up. Titanium implants with an elastic modulus of 80 GPa had a subsidence rate of 100 %.

Development and Validation of End-to-End Test for Stereotactic Radiosurgery

The purpose of this study is to evaluate End to End test and dosimetric test of small field SRS MapCHECK dosimeter. The Fundamental properties of the SRS MapCHECK Diode Detector such as reproducibility, linearity, Energy dependence, Dose rate dependency and output factor are studied for 6MV FFF energy photon beams. All dosimetric test carried out on a medical accelerator consisting High definition 120 multileaf collimator (HD120 MLC), provide stereotactic treatments. End to End test of SRSMapCHECK carried out with StereoPHAN Cylindrical Phantom with CT and MRI inserts. The E2E test includes MRI scan, CT scan, Target contouring on CT/MRI scan, MRI/CT image fusion, Treatment planning and Dose delivery. SRS MapCHECK comprise of 1013 solid state diode detector, are equally spaced at 2.47mm. The active detector area is 0.48mm x 0.48mm and resolution is 0.007mm3. The maximum field size is 7 X 7 cm2. Before to start dosimetric measurement the calibration of SRS MapCHECK and StereoPHAN is necessary. The calibration process includes background measurement, array calibration and StereoPHAN factor calculation. The reproducibility of SRS MapCHECK checked by measuring output for 5 consecutive days for 6MV FFF beam with field size 5x5cm2. The Linearity of dose measurement also evaluated. The response of SRS MapCHECK to different energy (6, 10 & 15MV) also studied. Dose rate dependency also studied by varying dose rate from 400 to 1400 MU/min. Output Factor for different field sizes ranging from 1 x 1 cm2 to 7 x 7 cm2 was measured. Geometric accuracy of inserts volumes are find with CT and MRI fusion. Actual Insert volumes of Central Sphere, Right Sphere, Left Sphere are 4.17cc and 0.52 cc, 0.52cc respectively. The TPS measured volume on CT scan is 4.09cc, 0.52cc and 0.53 cc respectively similarly on MRI TPS measured volume is 4.22cc, 0.50cc and 0.52cc. The % variation on CT volume is less than 2%. For MRI the % difference for right sphere is -4.0%, central and left side are less than 2% The reproducibility of SRS MapCHECK output is well within less than 2% of the first day measurement. The SRS MapCHECK showed linear dose response for energy 6 MV FFF. Energy Dependency checked for 6MV, 10MV and 15MV with fixed dose rate 600MU/min it showed linear response to energy. We found SRS MapCHECK are independent on dose rate. Output factor was measured and compared with pinpoint chamber 0.015cc. SRS MapCHECK showed under response compared to pinpoint chamber for field size 1 x 1 cm2 to 4 x 4 cm2 and showed over response from the 5 x 5 cm2 to 7 x 7 cm2 The gamma analysis done with Dose difference 3% and Dose to agreement 3mm, we also checked with DAT 2mm, 1mm with threshold 10%. The result of gamma passing is 97.6%, 96.8% and 95.8 % respectively. All dosimetric test performed on SRS MapCHECK are comparable with ionization chamber measurement and clinically acceptable. It is an effective tool for E 2 E test and patient’s specific QA for SRS Patients.

P9. Dimethyloxaloylglycine (DMOG) preconditioning of adipose-derived mesenchymal stem cells as strategy for enhancing posterolateral lumbar fusion in a rat model

BACKGROUND CONTEXT Transplantation of adipose-derived mesenchymal stem cells (ADSCs) has become a promising approach for bone regeneration therapies, particularly in elderly patients. However, poor cell survival in vivo after implantation due to the ischemic tissue environment has been one of the major limitations of the effectiveness of this strategy. Hypoxia Inducible Factor-1α (HIF-1α) plays an important role in angiogenic-osteogenic coupling during bone regeneration, as it is a critical mediator of the adaptive cell response to hypoxia. DMOG treatment has been demonstrated to stabilize cellular expression of HIF-1α in cells, as well as enhance osteogenic and angiogenic capacity of MSCs. By therapeutically targeting both osteogenesis and vascularization via DMOG preconditioned MSCs, this tissue-engineering approach sought to yield superior bone quality and integration, thereby increasing rates of spinal fusion. PURPOSE We aimed to demonstrate that preconditioning adipose (ADSC)-derived (AD) MSCs with DMOG prior to implantation will prolong survival in vivo and improve spinal fusion outcomes in a rat model. STUDY DESIGN/SETTING In vivo study via a rat posterolateral spinal fusion model. PATIENT SAMPLE Syngeneic 6-8 week old Lewis rats. OUTCOME MEASURES Manual palpation scoring was performed by blinded researchers as follows: 0 = non-fused; 1 = partial fusion, some motion across operative joint; and, 2 = fused, no motion across the operated joint. MicroCT images were used to assess fusion mass volume (mm^3) via ImageJ software and determine CT fusion score (0 = non-fused; 1 = unilateral fusion; 2 = bilateral fusion). METHODS ADSCs were isolated from the inguinal fat pads of syngeneic 6-8 week old Lewis rats and cultured in vitro. When passage 1 (P1) ADSCs reached approximately 80% confluency they were pre-conditioned for 24 hours with 1 ng of DMOG (Fisher Scientific). After pre-conditioning, 2 × 10^6 ADSCs were seeded onto Vitoss (Stryker) bone graft substitute scaffolds for subsequent transplantation. Posterolateral spinal fusion surgery at L4-L5 was performed on 18 female Lewis rats divided into 2 experimental groups: [1] Vitoss+ADSCs pre-conditioned with DMOG; and, [2] Vitoss+non pre-conditioned ADSCs. Fusion was evaluated eight weeks post-surgery. Manual palpation scoring evaluated the motion across the operated joint, and MicroCT images were assessed for fusion mass volume and CT fusion. RESULTS Preliminary microCT imaging data suggest that DMOG pre-conditioned ADSCs (n=12) yielded significantly higher fusion mass volumes than non-preconditioned ADSCs (n=6) (23.49 mm^3 vs. 15.39 mm^3, respectively, p=.001). DMOG pre-conditioned ADSCs showed a trend towards higher rates of fusion and manual palpation scores compared to non-conditioned ADSCs (1.16 vs. 0.50, respectively, p=.06; and 1.25 vs. 0.66, respectively, p>.05). CONCLUSIONS In our rat posterolateral fusion model, DMOG pre-conditioned ADSCs displayed an increased fusion mass volume, CT fusion rates, and manual palpation score compared to non-conditioned ADSCs. Ongoing histological studies will evaluate whether there are any differences in the quality of bone formed within the fusion masses. Future studies will also compare whether these results are also similar in bone marrow-derived MSCs. FDA DEVICE/DRUG STATUS Dimethyloxaloylglycine (Investigational/Not approved)

Rapid and high-quality 3D fusion of heterogeneous CT and MRI data for the human brain

Rapid and high-quality 3D fusion of heterogeneous CT and MRI data for the human brain

A comparison of ventilation perfusion combined with pulmonary perfusion fusion tomography imaging and CT pulmonary angiography for diagnosis of pulmonary embolism

Objective To compare the diagnostic value of ventilation/perfusion (V/Q) combined with pulmonary perfusion single photon emission computed tomography combined with CT (SPECT/CT) fusion tomography imaging and computed tomographic pulmonary angiography (CTPA) in evaluation of pulmonary embolism. Methods We retrospectively analyzed 60 patients with clinically suspected pulmonary embolism diagnosed in Shanxi Dayi Hospital from May 2015 to May 2017. All patients underwent pulmonary V/Q imaging and lung perfusion SPECT/CT fusion tomography, and CTPA inspections were completed within 3 days. The final clinical diagnosis and follow-up confirmed the presence or absence of pulmonary embolism. The diagnostic efficacy of two imaging methods for pulmonary embolism were calculated and compared. Results Of the 60 cases of patients, 33 cases were diagnosed with pulmonary embolism; the sensitivity, specificity, and accuracy of V/Q combined with pulmonary perfusion SPECT/CT fusion tomography were 96.97% (32/33), 92.59% (25/27) and 95% (57/60), respectively; the sensitivity, specificity, and accuracy of CTPA were 81.82% (27/33), 92.59% (25/27) and 86.67% (52/60), respectively; both have no diagnostic uncertainty, there was no significant difference in the qualitative diagnosis of pulmonary embolism between the two examination methods (P>0.05). V/Q combined with pulmonary perfusion SPECT/CT fusion tomography found 253 lung segment and 50 unmatched sub-pulmonary segments, including 15 V/Q mismatch lung segment and 5 sub-segment caused by lung lesions which were confirmed by lung perfusion SPECT/CT fusion image (5 interlobular or pleural effusion, 4 local emphysema and pulmonary bulla, 3 interlobular hypertrophy, 8 pulmonary parenchymal inflammation); CTPA found 3 sub-segmental pulmonary filling defects, 6 cases of false-negative cases were multiple sub-pulmonary segment pulmonary embolism. Conclusions V/Q combined with pulmonary perfusion SPECT/CT fusion tomography is similar to CTPA in diagnosing pulmonary embolism, and both of them have better diagnostic efficacy; the former has advantages in the diagnosis of sub-pulmonary segment pulmonary embolism, and can exclude false-positive diagnoses due to other lung lesions and provide additional diagnostic information for lung disease. Key words: Pulmonary embolism; Tomography, emission-computed, single-photon; Radionuclide imaging; Angiography; Tomography, spiral computed

Clinical Utility of CT Fusion Imaging in Guiding Trans-catheter Paravalvular Leak Closure

Paravalvular leaks (PVL) occur in 2–12% of patients after mitral valve replacement and in 1–5% after aortic valve replacement 1,2 and can cause heart failure and/or hemolytic anemia. Redo surgery h...

Accuracy of SPECT/CT fusion imaging in differential diagnosis of benign and malignant spinal lesions

Objective To analyze and discuss the clinical value of single photon emission computed tomography(SPECT)/CT fusion imaging in differentiating benign and malignant spinal lesions. Methods From January 2017 to January 2018, 70 cases with benign and malignant spinal lesions in Shanxida Hospital were studied.SPECT/CT fusion imaging and SPECT examination were used to compare the diagnosis results between the two groups. Results After SPECT diagnosis, a total of 98 bone metastatic lesions were detected, including 10 false positive lesions, 60 benign lesions and 28 false negative lesions.After SPECT/CT fusion imaging, there were 100 lesions, including 4 false positive lesions, 59 benign lesions and 37 false negative lesions.In this study, a total of 145 lesions were found in 70 patients with benign and malignant spinal lesions, including 95 benign lesions and 50 malignant lesions.The specificity, sensitivity and accuracy of SPECT/CT fusion imaging [95.79%(91/95), 92.00%(46/50), 93.79%(136/145)] were higher than those of the control group [82.11%(78/95), 64.00%(32/50), and 82.76%(120/145)], the differences were statistically significant(χ2=9.048, 11.422, 9.578, all P<0.05). Conclusion In the diagnosis of benign and malignant spinal diseases, SPECT/CT fusion imaging can accurately distinguish benign and malignant lesions, and clearly reflect the development of the disease, which lay a solid foundation for good treatment in the future. Key words: Spinal lesion; Tomography, emission-computed, single-photon; Tomography, X-ray computed; Malignant; Benign; Fusion imaging; Specificity; Sensitivity; Accuracy; False positive

Applicator Reference CT Fusion Improves Clinical Accuracy of MR-Based Titanium Tandem and Ring Localization and Reconstruction

Guidelines for GYN brachytherapy recommend the use of MR images for contouring treatment volumes. Removing the need for a patient CT applicator reconstruction can improve planning efficiency, reduce imaging dose, and reduce time patient has the applicator in place. However, titanium tandem and ring applicators (T&R) are more difficult to visualize in a MR than in a CT. In this study, we evaluated the reproducibility of MR-only based digitization and propose an alternative workflow where a reference T&R CT is used as an intermediary step during planning.

Do clinical results of arthroscopic subtalar arthrodesis correlate with CT fusion ratio?

BackgroundCT analysis of arthroscopic subtalar arthrodesis rarely finds complete fusion. The aim of the present study was to determine, at 12 months’ follow-up of arthroscopic subtalar arthrodesis: (1) CT fusion ratio, (2) functional results, and (3) the correlation between the two. HypothesisIncomplete fusion ratio does not impair the result of arthrodesis. Materials and methodsA continuous series of 22 arthroscopic subtalar arthrodeses was assessed at 12 months’ follow-up. The procedure used a posterior approach without bone graft, with stabilization by 2 compression screws. Clinical assessment comprised of a numerical analog pain scale (NAS, AOFAS and SF12) scores. Satisfaction was assessed on an NAS and on Odom's criteria. CT analysis at 12 months determined the posterior subtalar joint fusion ratio. ResultsAt follow-up, 2 patients showed non-union (9.1%). Among the 20 patients with fusion (91%), fusion was complete (>67°) in 16 (72.7%) and partial (34–66%) in 4 (18.2%). Mean fusion ratio at 12 months was 77.7%±14.8 (range, 36–98%). Functional gains (Δ) were: Δ pain NAS 4.8±2 (range, 1–10) and Δ AOFAS score 31.1±14 (range, 10–59). Mean satisfaction score was 8±2.5 (range, 3–10). There were no significant correlations between fusion ratio and any clinical or satisfaction scores. ConclusionAlthough clinical gain was systematic, functional and satisfaction scores were independent of whether subtalar fusion ratio was partial or complete. Level of evidenceIV, retrospective study.

Investigation of Computed Tomography Exposure Dose for Whole-body 18F-FDG PET/CT Examination in Chugoku-Shikoku Regions

We investigated the way of thinking about the CT dose setting, the exposure dose (CTDIvol, DLP) and the image quality (standard deviation of liver: SDliver) of whole-body PET/CT examinations in the Chugoku and Shikoku regions for the optimized CT dose setting. It was researched in the target 29 facilities which is equipped with 18F-FDG, PET/CT scanner in that regions. We examined how to determine the dose of complete physical PET/CT setting, the CT radiation dose (CTDIvol and DLP) and the image quality of CT fusion image that is the standard deviation of liver CT value in each facility. The optimized CT dose was lower than the diagnostic CT in many facilities. The 75th percentile CTDIvol was 6.01 mGy. The 75th percentile DLP was 560.9 mGy ×cm. The SDliver was 14.6±5.3 HU. The CT condition was low setting in comparison with diagnostic CT in many facilities. The exposure dose was lower than the diagnostic CT dose. The image quality of the normal region of liver was very close to the diagnostic CT. Even though it was low dose, images were less noise components.

Application of fused image in detecting abnormalities of temporomandibular joint

To present a method for image fusion of cone beam CT (CBCT)/CT and MRI and to explore whether the image data sets fused in such a way could aid the detection of temporomandibular joint (TMJ) anatomical structures and lesions. There were five cases included in this study. One case was space occupying lesion giant cell tumour of tendon sheaths, one case was chronic inflammation in the condyle, one case was articular disc calcification of the bilateral TMJs, and the other two cases were TMJ disorders (anterior disc displacement without reduction). The digital imaging and communications in medicine format data of CT/CBCT and MRI of the cases were collected, and then imported to the Amira visual software where the registration process was conducted. Based on the different scan model, the registration process could be separated into automatic registration of CT/CBCT with quadrature slice MR images and the semi-automatic registration of CT/CBCT with oblique slice MR images by altering the registration parameters. Rigid transform model and the similarity metric of normalization mutual information was used for registration in the present study. The relationship between the soft mass and hard tissue was shown clearly in the fused images when compared to sole observation of CBCT/CT or MR images. The fused images could define the tumour outline and the destructive bone clearly in the same image. The fused results helped the observers to ensure uncertain defects which could not be confirmed only by one image data set. The CT/CBCT and MR images could be fused to aid detection of TMJ anatomical structures and related lesions.

Brain CT and MRI medical image fusion using convolutional neural networks and a dual-channel spiking cortical model.

The aim of medical image fusion is to improve the clinical diagnosis accuracy, so the fused image is generated by preserving salient features and details of the source images. This paper designs a novel fusion scheme for CT and MRI medical images based on convolutional neural networks (CNNs) and a dual-channel spiking cortical model (DCSCM). Firstly, non-subsampled shearlet transform (NSST) is utilized to decompose the source image into a low-frequency coefficient and a series of high-frequency coefficients. Secondly, the low-frequency coefficient is fused by the CNN framework, where weight map is generated by a series of feature maps and an adaptive selection rule, and then the high-frequency coefficients are fused by DCSCM, where the modified average gradient of the high-frequency coefficients is adopted as the input stimulus of DCSCM. Finally, the fused image is reconstructed by inverse NSST. Experimental results indicate that the proposed scheme performs well in both subjective visual performance and objective evaluation and has superiorities in detail retention and visual effect over other current typical ones. Graphical abstract A schematic diagram of the CT and MRI medical image fusion framework using convolutional neural network and a dual-channel spiking cortical model.

Gross tumour delineation on computed tomography and positron emission tomography-computed tomography in oesophageal cancer: A nationwide study

Background and purposeAccurate delineation of the primary tumour is vital to the success of radiotherapy and even more important for successful boost strategies, aiming for improved local control in oesophageal cancer patients. Therefore, the aim was to assess delineation variability of the gross tumour volume (GTV) between CT and combined PET-CT in oesophageal cancer patients in a multi-institutional study. Materials and methodsTwenty observers from 14 institutes delineated the primary tumour of 6 cases on CT and PET-CT fusion. The delineated volumes, generalized conformity index (CIgen) and standard deviation (SD) in position of the most cranial/caudal slice over the observers were evaluated. For the central delineated region, perpendicular distance between median surface GTV and each individual GTV was evaluated as in-slice SD. ResultsAfter addition of PET, mean GTVs were significantly smaller in 3 cases and larger in 1 case. No difference in CIgen was observed (average 0.67 on CT, 0.69 on PET-CT). On CT cranial-caudal delineation variation ranged between 0.2 and 1.5 cm SD versus 0.2 and 1.3 cm SD on PET-CT. After addition of PET, the cranial and caudal variation was significantly reduced in 1 and 2 cases, respectively. The in-slice SD was on average 0.16 cm in both phases. ConclusionIn some cases considerable GTV delineation variability was observed at the cranial-caudal border. PET significantly influenced the delineated volume in four out of six cases, however its impact on observer variation was limited.

Value of pulmonary perfusion tomography/low dose CT fusion imaging in the diagnosis of acute pulmonary embolism

Objective To evaluate the diagnostic efficacy of the pulmonary perfusion tomography combined with low dose CT scan (Q SPECT/CT) in detecting acute pulmonary embolism (PE) by comparing with pulmonary ventilation/perfusion (V/Q) SPECT imaging. Methods A total of 203 patients suspected with acute PE (88 males, 115 females, age range 19-94 years) from January 2013 to December 2015 were enrolled in this retrospective study. All patients underwent V/Q SPECT and low dose CT scan. Final clinical diagnosis was regarded as the gold standard. The diagnostic consistency and diagnostic efficacy of Q SPECT/CT were compared with those of V/Q SPECT. χ2 test was used to compare the differences between the two methods. Kappa analysis was used to analyze the agreement of them. Results The coincidence rate of Q SPECT/CT and V/Q SPECT was 94.09%(191/203), Kappa=0.882, P 0.05). Conclusion In the majority of patients with suspected acute PE, V/Q SPECT scan can be replaced by Q SPECT/CT, but it must be careful to select Q SPECT/CT for patients with COPD history. Key words: Pulmonary embolism; Tomography, emission-computed, single-photon; Tomography, X-ray computed; Technetium; Technetium Tc 99m aggregated albumin

Diagnostic imaging in chronic otitis media: does CT and MRI fusion aid therapeutic decision making? - a pilot study.

Despite the recent advances in otosurgery diagnosis of cholesteatoma and qualification for surgery remains an issue in contemporary laryngology. In cases of cholesteatoma recidivism, it is of utmost importance to properly locate the pathology in the middle ear to plan surgical approach. Magnetic Resonance imaging in diffusion-weighted non-echoplanar sequences (non-EPI DWI) enables cholesteatoma detection as small as 2 mm and could potentially prevent unnecessary second-look surgery. Computed Tomography of the temporal bone allows precise visualization of bony structures and topographical landmarks of the middle ear. A fusion of both imaging modalities combines the advantages of these techniques. Five patients treated in the Department of Otolaryngology, the Medical University of Lodz for probable cholesteatoma recidivism were included in this study. A high-resolution CT scan of the temporal bone and an MRI scan including non-EPI sequences was obtained in all patients. A fusion of CT and MRI studies was conducted using OsirixMD software. Fist, CT studies were fused with MRI BFFE sequences, then non-EPI sequences were added. Finally, if the patient qualified for surgical treatment histopathological diagnosis was compared with MRI results. CT scans were analyzed to establish the extent of previous surgical interventions and anatomical landmarks preservation. In all cases, MRI results were suspicious of cholesteatoma recidivism. Four cases were confirmed in postoperative histopathological evaluation, there was one false positive case when intraoperatively scar tissue was identified, which was later confirmed as connective tissue upon histopathological evaluation. CT and MRI fusion provides a helpful diagnostic tool in preparation for surgery in patients with suspected cholesteatoma recidivism.

Ultrasound and cone beam CT fusion for liver ablation: technical note

Purpose: To assess the feasibility of fusion imaging between intraprocedural ultrasound (US) and contrast-enhanced cone-beam CT (CBCT) for small (< 2 cm) hepatocellular carcinoma (HCC).Materials and methods: Six patients (five males, one female, age range 58–80, mean 69 years), with small (mean diameter 16.8 mm) HCC poorly visible at US underwent percutaneous microwave ablation under US/CBCT fusion guidance. During general anesthesia with apnea control, a contrast- enhanced CBCT was acquired with an active tracker. Subsequently, real time US images were fused with CBCT images, and treatment performed under fusion imaging guidance. Feasibility of fusion imaging and percutaneous ablation were assessed, correct targeting (distance from center of tumor and center of ablation area <5 mm) and one-month primary technical efficacy were evaluated. Major and minor complications as well as overall procedural time were recorded.Results: US/CBCT fusion was feasible in all cases, allowing for completion of the treatment as previously planned (technical success 100%). Correct targeting was achieved in 4/6 cases (66%), while in two cases, center of tumor and center of ablated area were respectively 7 and 8 mm distant. At 1 month CT scan, all tumors were completely ablated (primary technical efficacy 100%). No major or minor complications occurred. Mean overall procedure time was 127 min.Conclusions: US/CBCT fusion is a feasible technique for liver ablation, and might represent a useful tool to increase the correct targeting of poorly US-visible HCC nodules in the angio suite.

Fusion of CT and MR scans of lumbar spine using discrete image transforms

Fusion of CT and MR scans of lumbar spine using discrete image transforms

Tibiotalocalcaneal Fusion Rate with a Novel Pseudoelastic Intramedullary Nail with NiTiNOL

Category: Ankle Arthritis Introduction/Purpose: Tibiotalocalcaneal (TTC) fusion is a salvage operation for patients with significant arthritis and deformity of ankle and subtalar joints. Despite overall clinic success, fusion across both joints continues to be a major challenge with nonunion rates reported up to 48% [Franceschi]. Aside from certain patient comorbidities, nonunion may result when compression across the joint is lost in the setting of bone resorption. The use of a pseudoelastic intramedullary nail has been shown to maintain compression across fusion site in response to bone resorption. The purpose of this study was to evaluate the fusion rate in a high-risk population at a tertiary care center using a psuedoelastic intramedullary nail with an internal nitinol element. Methods: After obtaining IRB approval, a retrospective review of consecutive patients that underwent procedures with TTC fusion with novel intramedullary nail system with super elastic internal nickel titanium (NiTiNOL, DynaNail, Medshape Inc, Atlanta, GA) was performed at a single academic institution. From 2014 to 2016, 58 patients were identified, 55 of which had minimum one year follow up or clinical and radiographic fusion (20 months average, range 6-41 months). The primary outcome was radiographic fusion analysis which was reviewed by three authors. Fusion was determined by consensus with criteria of 3 of 4 cortices with osseous bridging in asymptomatic patients[1, 2] or CT fusion based on Glazebrook et. al. criteria for hindfoot fusion[3, 4]. Average age of this cohort was 59 (SD= 16.3) years with BMI average 33.1 (SD= 8.87). Exclusion criteria include: follow-up less than 12 months in non-fused patients, and incomplete clinical or radiologic data. Results: The fusion rate in this high-risk population was 80.0% with the use of the NiTiNOL tibiotalocalcaneal nailing system. Univariate analysis demonstrated no significant difference (p&gt;0.05) in fusion rates with patient comorbidities that portend to non-union: current or former history of tobacco use, diabetes mellitus, rheumatoid arthritis, nor patients with chronic kidney disease. The average BMI in the fusion group was 31.97 compared to 27.4 in the non-union group (p=0.016). There were 5 deep infections requiring reoperation with a single patient requiring a below the knee amputation. Seven patients required a second operation for removal of prominent interlocking screws. Conclusion: This preliminary data demonstrates fusion rates with this novel intramedullary device are consistent with historical data. These findings are encouraging in that this nailing system shows equal rates of fusion in patients with high risk comorbidities for non-union compared to historical controls demonstrating increased non-union rates in diabetics, patients with chronic renal failure and those with a history of smoking. This Tibiotalocalcaneal nailing system is safe and offers theoretical sustained compression with up to 6 mm of resorption or settling.

Multi-modality 3D mandibular resection planning in head and neck cancer using CT and MRI data fusion: A clinical series

Objectives3D virtual surgical planning (VSP) and guided surgery has been proven to be an effective tool for resection and reconstruction of the mandible. Currently, most widely used 3D VSP approaches to mandibular resection do not include detailed tumour information in the VSP. This manuscript presents a strategy where the aim was to incorporate tumour visualisation into the 3D virtual plan. Three-dimensional VSP of the mandibular resections was based on the fusion of CT and MRI data which was subsequently applied in clinical practice. MethodsAll patients diagnosed with oral squamous cell carcinoma between 2014 and 2017 at the University Medical Centre Groningen were included. The tumour was delineated on the MRI data, after which this dataset was fused with the CT bone data in order to construct a 3D bone and tumour model for virtual resection planning. Guided resections were performed and post-operative evaluation quantified the accuracy of the resection. The histopathological findings and patient and tumour characteristics were compared to those of a historical cohort (2009–2014) of conventional mandibular continuity resections. ResultsTwenty-four patients were included in the cohort. The average deviation from planned resection was found to be 2.2 mm. Histopathologic analysis confirmed all resection planes (bone) were tumour free, compared to 96.4% in the historic cohort. ConclusionMRI-CT base tumour visualisation and 3D resection planning is a safe and accurate method for oncologic resection of the mandible. It is an improvement on the current methods reported for 3D resection planning based solely on CT data.

Quantitative analysis of near-implant magnesium accumulation for a Si-containing coated AZ31 cage from a goat cervical spine fusion model

BackgroundMagnesium (Mg) released from Mg-based implants degradation is believed to be effective in improving osteogenesis, however, studies focusing on Mg-based interbody cages are limited and fusion success was never reported. As excessive Mg accumulation can inhibit new bone formation, this study is designed to explain the possible reasons for the fusion failure of Mg-based cages by analyzing the relationships between the intervertebral Mg accumulation and the resulting interbody fusion.MethodsThe experimental cage was consisted of magnesium alloy (AZ31) substrate and Silicon (Si) -containing coating. C3/C4 and C5/C6 of 24 goats were implanted with cage or autologous iliac crest bone graft (Control group), which were analyzed at 3, 6, 12, and 24 weeks post-operatively. Intervertebral Mg concentrations, Mg-related Calcium (Ca)/ Phosphorus (P) ratios, radiological evaluations and histological findings were recorded for analyzing the relationships between the three of cage corrosion, Mg accumulation, and interbody fusion.ResultsIntervertebral Mg levels were significantly increased after cage implantation, especially in the areas that were closer to the cages at 3 weeks post-operatively, and these increased concentrations could persist up to 12 weeks post-operatively, indicating a relatively rapid corrosion process. Significantly lower Mg levels were only found at 24 weeks post-operatively, but these levels were still higher than those of the control group. In addition, Mg was found to be widely distributed at the intervertebral space since high Mg concentrations could even be detected at the posterior boundary of the vertebral body. Under this Mg accumulation profile, interbody fusion was not achieved, as indicated by the decreased Ca/P ratios, low CT fusion scores and negative histological results.ConclusionsIntervertebral excessive Mg accumulation might be the primary reason for interbody fusion failure. Quantitative Mg analysis can offer insight into the association between cage degeneration and biological response.