In which direction does skin move during joint movement?

BACKGROUND/ PURPOSE: A skin movement artifact is a major problem in three-dimensional motion analysis. Furthermore, skin tension lines are important in plastic surgery. Skin tension depends upon the body area and the direction of resistance. From the perspective of skin continuity and clinical observation, we hypothesized that the contralateral side of the skin of the extremities moves in the opposite direction. This study aimed to examine kinematics of thigh skin including movement direction during pelvic sway. METHODS: Fifteen healthy men participated in this study. Kinematic data were obtained using a three-dimensional motion analysis system. To detect opposite skin movement, 42 markers were attached to the front, back, lateral, and medial sides of the thigh and pelvis. Front and back markers in the sagittal plane and lateral and medial markers in the frontal plane were arranged in a line connecting the hip and ankle joint centers, respectively. Subjects performed maximal pelvic movements in the anterior-posterior and rightward-leftward directions. RESULTS: The results showed that the front skin of the thigh was transferred upward and that the back skin was transferred downward during pelvic anterior sway. Opposite skin movements were observed during posterior pelvic sway. We also found that the lateral skin was transferred upward and that the medial skin was transferred downward during hip adduction and vice-versa during hip abduction. CONCLUSION: These findings suggest that the skin moves according to certain physiological rules.

Deep-learning-based automatic facial bone segmentation using a two-dimensional U-Net.

The use of deep learning (DL) in medical imaging is becoming increasingly widespread. Although DL has been used previously for the segmentation of facial bones in computed tomography (CT) images, there are few reports of segmentation involving multiple areas. In this study, a U-Net was used to investigate the automatic segmentation of facial bones into eight areas, with the aim of facilitating virtual surgical planning (VSP) and computer-aided design and manufacturing (CAD/CAM) in maxillofacial surgery. CT data from 50 patients were prepared and used for training, and five-fold cross-validation was performed. The output results generated by the DL model were validated by Dice coefficient and average symmetric surface distance (ASSD). The automatic segmentation was successful in all cases, with a mean± standard deviation Dice coefficient of 0.897 ± 0.077 and ASSD of 1.168 ± 1.962 mm. The accuracy was very high for the mandible (Dice coefficient 0.984, ASSD 0.324 mm) and zygomatic bones (Dice coefficient 0.931, ASSD 0.487 mm), and these could be introduced for VSP and CAD/CAM without any modification. The results for other areas, particularly the teeth, were slightly inferior, with possible reasons being the effects of defects, bonded maxillary and mandibular teeth, and metal artefacts. A limitation of this study is that the data were from a single institution. Hence further research is required to improve the accuracy for some facial areas and to validate the results in larger and more diverse populations.

Robust methods for automatic image-to-world registration in cone-beam CT interventional guidance.

PURPOSE: Real-time surgical navigation relies on accurate image-to-world registration to align the coordinate systems of the image and patient. Conventional manual registration can present a workflow bottleneck and is prone to manual error and intraoperator variability. This work reports alternative means of automatic image-to-world registration, each method involving an automatic registration marker (ARM) used in conjunction with C-arm cone-beam CT (CBCT). The first involves a Known-Model registration method in which the ARM is a predefined tool, and the second is a Free-Form method in which the ARM is freely configurable. METHODS: Studies were performed using a prototype C-arm for CBCT and a surgical tracking system. A simple ARM was designed with markers comprising a tungsten sphere within infrared reflectors to permit detection of markers in both x-ray projections and by an infrared tracker. The Known-Model method exercised a predefined specification of the ARM in combination with 3D-2D registration to estimate the transformation that yields the optimal match between forward projection of the ARM and the measured projection images. The Free-Form method localizes markers individually in projection data by a robust Hough transform approach extended from previous work, backprojected to 3D image coordinates based on C-arm geometric calibration. Image-domain point sets were transformed to world coordinates by rigid-body point-based registration. The robustness and registration accuracy of each method was tested in comparison to manual registration across a range of body sites (head, thorax, and abdomen) of interest in CBCT-guided surgery, including cases with interventional tools in the radiographic scene. RESULTS: The automatic methods exhibited similar target registration error (TRE) and were comparable or superior to manual registration for placement of the ARM within ∼200 mm of C-arm isocenter. Marker localization in projection data was robust across all anatomical sites, including challenging scenarios involving the presence of interventional tools. The reprojection error of marker localization was independent of the distance of the ARM from isocenter, and the overall TRE was dominated by the configuration of individual fiducials and distance from the target as predicted by theory. The median TRE increased with greater ARM-to-isocenter distance (e.g., for the Free-Form method, TRE increasing from 0.78 mm to 2.04 mm at distances of ∼75 mm and 370 mm, respectively). The median TRE within ∼200 mm distance was consistently lower than that of the manual method (TRE = 0.82 mm). Registration performance was independent of anatomical site (head, thorax, and abdomen). The Free-Form method demonstrated a statistically significant improvement (p = 0.0044) in reproducibility compared to manual registration (0.22 mm versus 0.30 mm, respectively). CONCLUSIONS: Automatic image-to-world registration methods demonstrate the potential for improved accuracy, reproducibility, and workflow in CBCT-guided procedures. A Free-Form method was shown to exhibit robustness against anatomical site, with comparable or improved TRE compared to manual registration. It was also comparable or superior in performance to a Known-Model method in which the ARM configuration is specified as a predefined tool, thereby allowing configuration of fiducials on the fly or attachment to the patient.

Fast and automatic periacetabular osteotomy fragment pose estimation using intraoperatively implanted fiducials and single-view fluoroscopy.

Accurate and consistent mental interpretation of fluoroscopy to determine the position and orientation of acetabular bone fragments in 3D space is difficult. We propose a computer assisted approach that uses a single fluoroscopic view and quickly reports the pose of an acetabular fragment without any user input or initialization. Intraoperatively, but prior to any osteotomies, two constellations of metallic ball-bearings (BBs) are injected into the wing of a patient's ilium and lateral superior pubic ramus. One constellation is located on the expected acetabular fragment, and the other is located on the remaining, larger, pelvis fragment. The 3D locations of each BB are reconstructed using three fluoroscopic views and 2D/3D registrations to a preoperative CT scan of the pelvis. The relative pose of the fragment is established by estimating the movement of the two BB constellations using a single fluoroscopic view taken after osteotomy and fragment relocation. BB detection and inter-view correspondences are automatically computed throughout the processing pipeline. The proposed method was evaluated on a multitude of fluoroscopic images collected from six cadaveric surgeries performed bilaterally on three specimens. Mean fragment rotation error was 2.4 ± 1.0 degrees, mean translation error was 2.1 ± 0.6 mm, and mean 3D lateral center edge angle error was 1.0 ± 0.5 degrees. The average runtime of the single-view pose estimation was 0.7 ± 0.2 s. The proposed method demonstrates accuracy similar to other state of the art systems which require optical tracking systems or multiple-view 2D/3D registrations with manual input. The errors reported on fragment poses and lateral center edge angles are within the margins required for accurate intraoperative evaluation of femoral head coverage.

Expression of polysialic acid and STX, a human polysialyltransferase, is correlated with tumor progression in non-small cell lung cancer.

Polysialic acid (PSA) is a carbohydrate composed of a linear homopolymer of alpha-2-8-linked sialic acid residues and is mainly attached to the neural cell adhesion molecule (NCAM). Because of the large negative charge of PSA, presence of PSA attenuates the adhesive property of NCAM and increases the cellular motility. PSA expression on NCAM is developmentally regulated, and PSA plays important roles in formation and remodeling of the neural system through regulation of the adhesive property of NCAM. Expression of the polysialated form of NCAM has been also demonstrated in some malignant tumors, such as Wilms' tumor and small cell lung cancer. Despite the possible importance as an onco-developmental antigen, however, significance of PSA expression in most malignant tumors has not been revealed. Therefore, PSA expression in non-small cell lung cancer was assessed in the present study. PSA was expressed only in 5 (20.8%) of 24 pathological stage I cases, whereas it was expressed in most stage IV cases (76.8%, 11 of 14 cases). PSA expression was correlated with nodal metastasis and distant metastasis, but not with local extent of the primary tumor. Next, expression of polysialyltransferase genes (PST and STX genes) which controlled formation of PSA, was examined. The PST gene was constantly expressed in both normal lung tissue and tumor tissue of all cases. In contrast, the STX gene was not expressed in normal lung tissue of any case, and STX gene expression in tumor tissue was closely correlated with tumor progression. The STX gene was expressed only in 1 (4.2%) of 24 stage I cases, whereas it was expressed in most stage IV cases (85.7%, 12 of 14 cases). These results suggested that the PSA and STX genes could be new targets of cancer therapy as well as important clinical markers.

Prognostic significance of polysialic acid expression in resected non-small cell lung cancer.

Polysialic acid (PSA) is a carbohydrate attached mainly to the neural cell adhesion molecule. Because PSA is composed of a linear homopolymer of alpha-2-8-linked sialic acid residues and has a large negative charge, the presence of PSA attenuates the adhesive property of neural cell adhesion molecule and increases cellular motility. In an earlier study, we demonstrated that PSA and STX, a polysialyltransferase, were associated with tumor progression in non-small cell lung cancer (NSCLC) (F. Tanaka et al., Cancer Res., 60: 3072-3080, 2000). Therefore, in the present study, to assess the prognostic significance of PSA in resected NSCLC, a total of 236 patients who underwent complete resection for pathological (p)-stage I-IIIa disease were reviewed retrospectively. PSA was expressed in 44 of 236 (18.6%) patients, and the expression was correlated with p-stage disease. For all p-stage patients, 5-year survival rates for those with PSA-positive and PSA-negative tumors were 52.1% and 71.3%, respectively, demonstrating a significantly worse prognosis for the PSA-positive patients (P = 0.012). Analysis for only p-stage I patients also demonstrated a significantly worse prognosis for the PSA-positive patients; 5-year survival rates of the PSA-positive and the PSA-negative patients were 45.1% and 83.5%, respectively, (P < 0.001). In addition, there proved to be no difference in the postoperative survival among p-stage I, II, and IIIa patients when PSA expression was positive. Multivariate analysis confirmed that PSA expression was an independent factor to predict poor prognosis in resected NSCLC. These results suggested that PSA could be an important clinical marker and that preoperative induction and/or postoperative adjuvant therapies should be performed for PSA-positive NSCLC, even if the disease is classified as p-stage I.

Evaluation of angiogenesis in non-small cell lung cancer: comparison between anti-CD34 antibody and anti-CD105 antibody.

PURPOSE: Angiogenesis is an essential process in the progression of malignant tumors. Whereas pan-endothelial markers, such as CD34, are generally used in evaluation of angiogenesis, pan-endothelial antibodies react with not only "newly forming" vessels but also normal vessels just trapped within tumor tissues. It has been recently reported that anti-CD105 antibody preferentially reacts with "activated" endothelial cells in angiogenic tissues. Thus, the superiority of anti-CD105 monoclonal antibody (mAb) in evaluation of angiogenesis of non-small cell lung cancer (NSCLC) was assessed. EXPERIMENTAL DESIGN: A total of 236 patients with resected NSCLC were retrospectively reviewed. Intratumoral microvessel density (IMVD) was determined with an anti-CD34 mAb (CD34-IMVD) and with an anti-CD105 mAb (CD105-IMVD). RESULTS: The mean CD34-IMVD and CD105-IMVD were 179.9 and 41.6, respectively. Whereas CD34-IMVD was significantly correlated with the expression of vascular endothelial growth factor (P = 0.003), CD105-IMVD was more closely correlated with vascular endothelial growth factor expression (P < 0.001). The 5-year survival rate of the lower CD105-IMVD patients was 74.9%, significantly higher than that of the higher CD105-IMD patients (60.4%, P = 0.018). Whereas the 5-year survival rate of the lower CD34-IMVD patients seemed higher than that of the higher CD34-IMVD patients (63.7%), the difference did not reach a statistical significance (P = 0.137). Multivariate analysis confirmed that higher CD105-IMVD was a significant factor to predict poor prognosis (P = 0.029), whereas CD34-IMVD was not (P = 0.070). CONCLUSIONS: Anti-CD105 mAb proved to be superior to anti-CD34 mAb in evaluation of angiogenesis in NSCLC.

Rendering-Based Video-CT Registration with Physical Constraints for Image-Guided Endoscopic Sinus Surgery.

We present a system for registering the coordinate frame of an endoscope to pre- or intra- operatively acquired CT data based on optimizing the similarity metric between an endoscopic image and an image predicted via rendering of CT. Our method is robust and semi-automatic because it takes account of physical constraints, specifically, collisions between the endoscope and the anatomy, to initialize and constrain the search. The proposed optimization method is based on a stochastic optimization algorithm that evaluates a large number of similarity metric functions in parallel on a graphics processing unit. Images from a cadaver and a patient were used for evaluation. The registration error was 0.83 mm and 1.97 mm for cadaver and patient images respectively. The average registration time for 60 trials was 4.4 seconds. The patient study demonstrated robustness of the proposed algorithm against a moderate anatomical deformation.

Isolation and characterization of an N-linked oligosaccharide that is significantly increased in sera from patients with non-small cell lung cancer.

The structures of N-linked oligosaccharides present in human sera from 12 healthy volunteers and from 14 patients with non-small cell lung cancer (NSCLC) were analyzed by our recently developed partially automated systematic method. Thirty different structures of oligosaccharides were deduced, and these accounted for 84.1% of the total N-linked oligosaccharides present in human sera. All of the quantified oligosaccharide levels in healthy human sera were within twice the standard deviation. The amount of a triantennary trigalactosylated structure with one outer arm fucosylation (A3G3Fo) was found to be markedly increased in NSCLC patients in comparison to that in healthy volunteers (p < 0.01). No significant positive correlation with other clinical data was found. Serum A3G3Fo levels can thus be a novel marker for the diagnosis of NSCLC.

Quercetin and resveratrol potently reduce estrogen sulfotransferase activity in normal human mammary epithelial cells.

Estrogen sulfotransferase (EST) is the sole sulfotransferase expressed in normal human breast epithelial cells and has an important function in determining free estrogen hormone levels in these cells. In the present study we examined the inhibitory effect of the dietary polyphenols quercetin and resveratrol on EST activity, i.e. 17beta-estradiol (E2) sulfation. Both the compounds potently inhibited recombinant human EST in a competitive fashion with K(i) values of about 1 microM. In fact, both polyphenols could serve as substrates for EST. In order to extend the studies to more physiologically relevant conditions, we examined whether inhibition of EST also occurred in the intact cultured human mammary epithelial (HME) cells. The mean baseline EST activity (E2 sulfate formation) in the HME cells was 4.4 pmol/h per mg protein. The IC(50) for resveratrol was very similar to that for recombinant EST, i.e. about 1 microM. Surprisingly, quercetin was 10 times more potent in the HME cells with an IC(50) of about 0.1 microM, a concentration that should be possible to achieve from the normal dietary content of this flavonoid.

Biological features and preoperative evaluation of mediastinal nodal status in non-small cell lung cancer.

BACKGROUND: To examine whether biological features of primary tumor can help preoperative evaluation of mediastinal nodal status in non-small cell lung cancer. METHODS: A total of 450 patients who underwent tumor resection and mediastinal dissection were reviewed. p53 status and proliferative fraction (PI) were evaluated immunohistochemically. RESULTS: The accuracy of preoperative evaluation of mediastinal nodal status with computed tomography (CT) was 72.2%; mediastinal nodal metastases had not been revealed until operation in 59 patients (13.1%) (false-negative), and no metastasis was revealed in 66 patients (14.7%) although mediastinal nodal enlargement had been demonstrated by CT (false-positive). The number of false-negative patients was significantly larger when p53 aberrant expression was positive or when PI was higher. Combined with p53 status and PI, there were 27 false-negatives (24.1%) among patients with aberrant p53 expression and higher PI, whereas only two false-negatives (1.5%) among those with negative p53 expression and lower PI. CONCLUSIONS: Mediastinoscopy may be recommended for tumor showing aberrant p53 expression and higher PI, even when CT demonstrates no mediastinal nodal enlargement.

Left ventricular Doppler filling pattern in dilated cardiomyopathy: relation to hemodynamics and left atrial function.

This study attempted to examine the relation of left ventricular filling patterns to hemodynamic status and left atrial function in dilated cardiomyopathy. Transesophageal echocardiography and cardiac catheterization were performed in 41 patients with dilated cardiomyopathy (six with an ischemic origin). Transmitral, left atrial appendage, and pulmonary venous flow velocities were recorded with the pulsed Doppler method. Left atrial systolic function was assessed by the peak velocity of the left atrial appendage emptying wave and pulmonary venous flow reversal during atrial systole. Patients were classified into three groups according to their left ventricular filling patterns. Group 1 showed an abnormal relaxation pattern (E wave/A wave ratio <1, n = 17), group 2 had a normal or pseudonormal pattern (1 < or = E/A < 2, n = 11), and group 3 had a restrictive pattern (E/A > or = 2, n = 13). No differences were found among the groups with regard to age, gender, heart rate, and M-mode echocardiographic indices of left ventricular function. Compared with patients in group 1, those in groups 2 and 3 had more symptoms (New York Heart Association functional class III or IV) and had higher left ventricular filling pressures. The sensitivity of an E/A ratio > or = 1 for predicting a pulmonary capillary wedge pressure > or = 15 mm Hg was 75% and the specificity was 94%. Despite a similar increase of filling pressures, group 3 patients had a lower left atrial appendage emptying velocity, pulmonary venous flow reversal velocity, and mitral A velocity than did group 2 patients. The sensitivity and specificity of an E/A ratio > or = 22 for detecting left atrial dysfunction (left atrial appendage emptying velocity < or = 40 cm/sec) was 85% and 86%, respectively. In conclusion, among patients with dilated cardiomyopathy, those who had a restrictive or pseudonormal filling pattern were in a higher functional class and had higher filling pressures. Further studies are needed to determine the therapeutic and prognostic significance of left atrial dysfunction, which was common in patients with a restrictive pattern.

Surgery for non-small cell lung cancer: postoperative survival based on the revised tumor-node-metastasis classification and its time trend.

OBJECTIVE: To clarify results of surgery for non-small cell lung cancer (NSCLC) based on the new tumor-node-metastasis (TNM) classification revised in 1997 and its time trend. METHODS: A total of 921 patients operated from 1980-1994 were retrospectively reviewed. For analysis of time trend, they were grouped into three periods by the year of operation (period (1): 1980-1984, period (2): 1985-1989, and period (3): 1990-19-94). RESULTS: Concerning patients' characteristics, recent increase in the ratio of patients whose tumor was discovered at mass screening (31% in period (1), 40% in period (2), and 50% in period (3)), and increase in the ratio of p-stage IA patient (16, 20, and 29%, respectively) were marked. Decrease in the ratio of operation-related death and the ratio of exploratory thoracotomy was significant. Concerning level of operation, decrease in the ratio of pneumonectomy, increase in the ration of sublober resection and that of tracheal or bronchoplastic procedures were significant. Postoperative survival for all patients was significantly better in period (2) or (3) than that in period (1); no significant difference was demonstrated between period (2) and (3) (5-year survival rates: 35% for period (1), 56% for period (2), and 56% for period (3)). Stratified p-stage, improvement of postoperative survival in recent years was demonstrated in p-stage IIA, IIB, IIIA, and IIIB diseases. CONCLUSIONS: Postoperative survival for all NSCLC patients has been improved with significant increase of early-stage (p-stage IA) patients. Concerning level of resection, recent increase in patients who underwent sublobar resection and bronchoplastic procedures was marked.

Prognostic factors in patients with resected pathologic (p-) T1-2N1M0 non-small cell lung cancer (NSCLC).

OBJECTIVES: To clarify prognostic factors in resected pathologic (p-) T1-2N1M0 non-small cell lung cancer (NSCLC). METHODS: A total of 95 consecutive patients who underwent complete tumor resection and mediastinal dissection for pT1-2N1M0 NSCLC between 1976 and 1997 were retrospectively reviewed. p53 status and proliferative activity were evaluated immunohistochemically. RESULTS: The extent of N1 stations and p53 status proved to be significant prognostic factors. The 5-year survival rate for tumor without hilar node (#10) involvement was 66%, significantly higher than that for tumor with #10 involvement (39%, P<0.01). The 5-year survival rate for tumor with aberrant p53 expression was 37%, significantly lower than that for tumor without aberrant p53 expression (74%, P<0.01). There proved to be no significant difference in the prognosis between pT1 disease and pT2 disease; the 5-year survival rates for pT1 and pT2 diseases were 62 and 56%, respectively. Age, gender, performance status, grade of tumor differentiation, histological type, or proliferative activity were not significant factors. Multivariate analysis of prognostic factors using Cox's proportional hazard model confirmed these results. CONCLUSIONS: Involvement of the hilar node and aberrant p53 expression were significant factors to predict a worse prognosis in resected T1-2N1M0 NSCLC.

Development of a miniature intraventricular axial flow blood pump.

A new intraventricular axial flow blood pump has been designed and developed as a totally implantable left ventricular assist device (LVAD). This pump consists of an impeller combined with a guide-vane, a tube housing, and a DC motor. The pump is introduced into the LV cavity through the LV apex, and the outlet cannula is passed antegrade across the aortic valve. Blood is withdrawn from the LV through the inlet ports at the pump base, and discharged to the ascending aorta. Our newly developed axial flow pump system has the following advantages: 1) it is a simple and compact system, 2) minimal blood stasis both in the device and the LV cavity, 3) minimal blood contacting surface of the pump, 4) easy accessibility with a less invasive surgical procedure, and 5) low cost. A pump flow > 5 L/min was obtained against 100 mmHg differential pressure in the mock circulatory system. The pump could produce a passive pulsatile flow effect with a beating heart more efficiently than other non-pulsatile pumps because of minimal pressure drop and inertia along the bypass tract. Anatomic fit studies using dissected hearts of dilated cardiomyopathy (DCM) cadavers showed that this pump could smoothly pass through the aortic valve without any interference with mitral valve function. Recently, a dynamic pressure groove bearing and a miniature lip seal have been developed. The dynamic pressure groove bearing has a simple structure and acts as a pressure resistant sealing mechanism.(ABSTRACT TRUNCATED AT 250 WORDS)

[Intracranial subdural hematoma following spinal anesthesia].

We report a case of intracranial subdural hematoma following spinal anesthesia in a 28-year-old woman. Subdural hematoma is a very rare, but life-threatening complication. When a patient complains of persistent post spinal headache, one should consider the possibility of subdural hematoma and carry out a careful examination, including MRI or CT scan.

[Adjuvant chemotherapy for non-small cell lung cancer].

Surgery is the first choice for patients in the early stage of non-small cell lung cancer (NSC-LC). But, even for pathologic stage I patients, the post-operative survival remains unsatisfactory; the five-year survival rate is around 70 percent, in spite of potential curative resections. Therefore, post-operative adjuvant chemotherapy is considered to be necessary to improve the survival. Although many prospective randomized studies of post-operative adjuvant chemotherapy have been conducted, the efficacy of post-operative chemotherapy for NSCLC has not been proved (a consensus report of post-operative adjuvant treatment for NSCLC, 3rd IASLC Workshop, Bruges, August 1993). It has been recently reported by the West Japan Study Group for Lung Cancer Surgery (WJSG) that oral administration of UFT (a mixture of tegafur and uracil) as a post-operative adjuvant chemotherapy is effective for patients with complete resected NSCLC (stage I to III) and that UFT administration is tolerable with mild adverse effects in most patients. In order to improve postoperative survival of patients with more advanced stage NSCLC (e.g., bulky N2, III b), we has introduced biochemical modulation therapy using 5-FU, UFT combined with CDDP.

[Cellular metabolic consideration in the pathophysiology and the treatment of shock].

Shock is defined as the summation of cellular dysfunction and resultant impairment of the function in various organs. The typical such condition can be observed in shock-induced multiple organ failure (MOF). Therefore, the most effective and fundamental management against shock should be the improvement of such cellular dysfunction. The present study was undertaken to investigate the cellular metabolic abnormalities and their treatment in shock-induced MOF patients. The severity of cellular damage was evaluated with cellular injury score (CIS), which can be calculated by scoring the values of osmolality gap, arterial ketone body ratio and blood lactate. The CIS correlated significantly with the outcome and the number of failing organs in the MOF patients. Since tissue hypoxia and humoral mediator have been considered to play a key role in the development of such cellular dysfunction, protease inhibitor was administered to such patients and oxygen metabolism was improved with catecholamine. The CIS improved among survived MOF patients following those treatments. These results suggest that the shock-induced MOF is the summation of the cellular dysfunction which can be assessed with the CIS, and that such cellular dysfunction could be improved through the therapeutic approach to the humoral mediators and/or tissue oxygen metabolism.

[Skeletal muscle ventricle used for right ventricle assistance].

There are a number of advantages in using an electrically stimulated autogenous skeletal muscle to construct an auxiliary ventricle to assist a heart. The purpose of this study was to determine the feasibility of biological right ventricular assistance using long-term electrically stimulated skeletal muscle grafts. In fourteen dogs, the latissimus dorsi muscles and the right thoracodorsal nerves were exposed and unipolar pulse generator was implanted. The initial rate of 70 cycle/min. was increased to a rate of 100 cycle/min. Six or 12 months later, the latissimus dorsi was wrapped around a latex pouch equipped with inflow and outflow valved conduit (skeletal muscle ventricles; SMVs). The SMVs were connected to main pulmonary artery and right atrium. These SMVs were stimulated 20 Hz for 200 msec at a fixed rate of 90 cycle/min, the hemodynamic changes with or without skeletal muscle ventricular assistance (SMVA) were measured. In as animals the circulation failed after total right ventricular bypass without SMVA. But the SMVA increased aortic blood pressure, aortic blood flow, left atrial pressure and peak pulmonary pressure significantly. There was a linear correlation between central venous pressure and skeletal muscle ventricular assist flow. Histologic studies showed the conditioned muscles had a greater percentage of slow-twitch, fatigue resistant fibers on ATPase stain. These results suggested the long-term electrical conditioning skeletal muscle could be possible to use SMVs in humans to provide support in children with some types of congenital heart disease.

Deformable image registration with local rigidity constraints for cone-beam CT-guided spine surgery.

Image-guided spine surgery (IGSS) is associated with reduced co-morbidity and improved surgical outcome. However, precise localization of target anatomy and adjacent nerves and vessels relative to planning information (e.g., device trajectories) can be challenged by anatomical deformation. Rigid registration alone fails to account for deformation associated with changes in spine curvature, and conventional deformable registration fails to account for rigidity of the vertebrae, causing unrealistic distortions in the registered image that can confound high-precision surgery. We developed and evaluated a deformable registration method capable of preserving rigidity of bones while resolving the deformation of surrounding soft tissue. The method aligns preoperative CT to intraoperative cone-beam CT (CBCT) using free-form deformation (FFD) with constraints on rigid body motion imposed according to a simple intensity threshold of bone intensities. The constraints enforced three properties of a rigid transformation-namely, constraints on affinity (AC), orthogonality (OC), and properness (PC). The method also incorporated an injectivity constraint (IC) to preserve topology. Physical experiments involving phantoms, an ovine spine, and a human cadaver as well as digital simulations were performed to evaluate the sensitivity to registration parameters, preservation of rigid body morphology, and overall registration accuracy of constrained FFD in comparison to conventional unconstrained FFD (uFFD) and Demons registration. FFD with orthogonality and injectivity constraints (denoted FFD+OC+IC) demonstrated improved performance compared to uFFD and Demons. Affinity and properness constraints offered little or no additional improvement. The FFD+OC+IC method preserved rigid body morphology at near-ideal values of zero dilatation (D = 0.05, compared to 0.39 and 0.56 for uFFD and Demons, respectively) and shear (S = 0.08, compared to 0.36 and 0.44 for uFFD and Demons, respectively). Target registration error (TRE) was similarly improved for FFD+OC+IC (0.7 mm), compared to 1.4 and 1.8 mm for uFFD and Demons. Results were validated in human cadaver studies using CT and CBCT images, with FFD+OC+IC providing excellent preservation of rigid morphology and equivalent or improved TRE. The approach therefore overcomes distortions intrinsic to uFFD and could better facilitate high-precision IGSS.