Optimizing stereo-to-multiview conversion for autostereoscopic displays

We present a novel stereo-to-multiview video conversion method for glasses-free multiview displays. Different from previous stereo-to-multiview approaches, our mapping algorithm utilizes the limited depth range of autostereoscopic displays optimally and strives to preserve the scene's artistic composition and perceived depth even under strong depth compression. We first present an investigation of how perceived image quality relates to spatial frequency and disparity. The outcome of this study is utilized in a two-step mapping algorithm, where we (i) compress the scene depth using a non-linear global function to the depth range of an autostereoscopic display and (ii) enhance the depth gradients of salient objects to restore the perceived depth and salient scene structure. Finally, an adapted image domain warping algorithm is proposed to generate the multiview output, which enables overall disparity range extension.

Prognostic factors in lymph node metastases of prostatic cancer patients: the size of the metastases but not extranodal extension independently predicts survival

AIMS: To analyse tumour characteristics and the prognostic significance of prostatic cancers with extranodal extension of lymph node metastases (ENE) in 102 node-positive, hormone treatment-naive patients undergoing radical prostatectomy and extended lymphadenectomy. METHODS AND RESULTS: The median number of nodes examined per patient was 21 (range 9-68), and the median follow-up time was 92 months (range 12-191). ENE was observed in 71 patients (70%). They had significantly more, larger and less differentiated nodal metastases, paralleled by significantly larger primary tumours at more advanced stages and with higher Gleason scores than patients without ENE. ENE defined a subgroup with significantly decreased biochemical recurrence-free (P = 0.038) and overall survival (P = 0.037). In multivariate analyses the diameter of the largest metastasis and Gleason score of the primary tumour were independent predictors of survival. CONCLUSIONS: ENE in prostatic cancer is an indicator lesion for advanced/aggressive tumours with poor outcome. However, the strong correlation with larger metastases suggests that ENE may result from their size, which was the only independent risk factor in the metastasizing component. Consequently, histopathological reports should specify the true indicator of poor survival in the lymphadenectomy specimens, which is the size of the largest metastasis in each patient.

Low-grade endometrial stromal sarcoma with inferior vena cava tumor thrombus and intracardiac extension: radical resection may improve recurrence free survival

BACKGROUND: Endometrial stromal sarcoma (ESS) represents 0.2% of all uterine malignancies. Based on the mitotic activity, a distinction is made between low and high-grade ESS. Although the overall five-year survival rate for low-grade ESS exceeds 80%, about 50% of the patients show tumor recurrence, mostly after a long latency period. Tumor invasion of the great vessels is extremely rare. We describe a patient with advanced low-grade ESS with tumor invasion of the infrarenal aorta and the inferior vena cava. The patient presented with a large tumor thrombus extending from the inferior vena cava into the right atrium. METHODS: Review of literature and identification of 19 patients, including our own case report, with advanced low-grade ESS with invasion of the great vessels and formation of an inferior vena cava tumor thrombus. RESULTS: All 19 patients presented with an abdominal tumor mass and a tumor thrombus protruding into the inferior vena cava. The tumor thrombus extended into the right heart cavities in nine patients reaching the right atrium in four, the right ventricle in three and the pulmonary artery in two patients. There were 5 patients with an advanced primary tumor and 14 patients with an advanced recurrent tumor. Seven patients presented with synchronous metastatic disease and six patients with a pelvic tumor infiltrating the bladder, the rectosigmoid colon or the infrarenal aorta. Mean age at surgery was 45.9+/-12.3 years (median 47, range 25-65 years). Tumor thrombectomy was accomplished by cavatomy or by right atriotomy after installation of a cardiopulmonary bypass. There was no peri-operative mortality and a very low morbidity. Radical tumor resections were achieved in 10 patients. The follow-up for these 10 patients was 2+/-1.3 years (median 2, range 0.3-4.5 years). Nine patients remained recurrence free whereas one patient suffered an asymptomatic local recurrence. CONCLUSIONS: Low-grade ESS is a rare angioinvasive tumor with a high recurrence rate. Resection of an inferior vena cava tumor thrombus, even with extension into the right heart cavities, can be performed safely. Extensive radical surgery is therefore justified in the treatment of advanced tumor manifestations of a low-grade ESS potentially improving recurrence free survival.

The use of extraoral implants for distal-extension removable dentures: a clinical evaluation up to 8 years

PURPOSE: This retrospective study reports the clinical outcome following placement of extraoral implants in severely resorbed posterior ridges to support distal-extension removable dentures. MATERIAL AND METHODS: Consecutively treated patients with partially or completely edentulous ridges, with available bone height in the posterior region of 6 mm or less, were included in the study. Implants originally intended for extraoral use (Straumann) were placed in second molar regions and allowed to heal for 4 to 6 months before abutment connection. At recall appointments, the peri-implant hard and soft tissues were evaluated. Complications with implant components, as well as mechanical and structural failures of the prostheses, were recorded. Two-year survival rates were calculated and life table analyses undertaken. RESULTS: Twenty-nine patients (19 women and 10 men; average age 61.2 years, range, 44 to 75 years) were included in the study. Forty-seven extraoral implants in 26 patients were placed in the second molar site of the mandible. Two extraoral implants in 2 patients failed during the osseointegration phase, yielding an 8-year cumulative success rate of 91.8%. The mean distance from the extraoral implants to the most distal tooth/implant was 28.1 mm (range, 16.7 to 39.2 mm). Twenty-three extraoral implants were restored with magnets, 18 with ball anchors, and 4 with conical cylinders. Replacement of abutments and retention elements was necessary in 2 patients. Four abutments in 2 patients were disconnected from the restorations. CONCLUSIONS: Within the limits of the employed research design, extraoral implants may be used successfully to provide support for distal-extension removable dentures in severely resorbed posterior alveolar ridges.

Association of radiographic osteoarthritis, pain on passive movement and knee range of motion: A cross-sectional study

BACKGROUND Knee pain is associated with radiographic knee osteoarthritis, but the relationships between physical examination, pain and radiographic features are unclear. OBJECTIVE To examine whether deficits in knee extension or flexion were associated with radiographic severity and pain during clinical examination in persons with knee pain or radiographic features of osteoarthritis. DESIGN Cross-sectional data of the Somerset and Avon Survey of Health (SASH) cohort study. METHODS Participants with knee pain or radiographic features of osteoarthritis were included. We assessed the range of passive knee flexion and extension, pain on movement and Kellgren and Lawrence (K/L) grades. Odds ratios were calculated for the association between range of motion and pain as well as radiographic severity. RESULTS/FINDINGS Of 1117 participants with a clinical assessment, 805 participants and 1530 knees had complete data and were used for this analysis. Pain and radiographic changes were associated with limited range of motion. In knees with pain on passive movement, extension and flexion were reduced per one grade of K/L by -1.4° (95% CI -2.2 to -0.5) and -1.6° (95% CI -2.8 to -0.4), while in knees without pain the reduction was -0.3° (95% CI -0.6 to -0.1) (extension) and -1.1° (-1.8 to -0.3) (flexion). The interaction of pain with K/L was significant (p = 0.021) for extension but not for flexion (p = 0.333). CONCLUSIONS Pain during passive movement, which may be an indicator of reversible soft-tissue changes, e.g., reversible through physical therapy, is independently associated with reduced flexion and extension of the knee.

Periacetabular osteotomy restores the typically excessive range of motion in dysplastic hips with a spherical head

BACKGROUND Residual acetabular dysplasia is seen in combination with femoral pathomorphologies including an aspherical femoral head and valgus neck-shaft angle with high antetorsion. It is unclear how these femoral pathomorphologies affect range of motion (ROM) and impingement zones after periacetabular osteotomy. QUESTIONS/PURPOSES (1) Does periacetabular osteotomy (PAO) restore the typically excessive ROM in dysplastic hips compared with normal hips; (2) how do impingement locations differ in dysplastic hips before and after PAO compared with normal hips; (3) does a concomitant cam-type morphology adversely affect internal rotation; and (4) does a concomitant varus-derotation intertrochanteric osteotomy (IO) affect external rotation? METHODS Between January 1999 and March 2002, we performed 200 PAOs for dysplasia; of those, 27 hips (14%) met prespecified study inclusion criteria, including availability of a pre- and postoperative CT scan that included the hip and the distal femur. In general, we obtained those scans to evaluate the pre- and postoperative acetabular and femoral morphology, the degree of acetabular reorientation, and healing of the osteotomies. Three-dimensional surface models based on CT scans of 27 hips before and after PAO and 19 normal hips were created. Normal hips were obtained from a population of CT-based computer-assisted THAs using the contralateral hip after exclusion of symptomatic hips or hips with abnormal radiographic anatomy. Using validated and computerized methods, we then determined ROM (flexion/extension, internal- [IR]/external rotation [ER], adduction/abduction) and two motion patterns including the anterior (IR in flexion) and posterior (ER in extension) impingement tests. The computed impingement locations were assigned to anatomical locations of the pelvis and the femur. ROM was calculated separately for hips with (n = 13) and without (n = 14) a cam-type morphology and PAOs with (n = 9) and without (n = 18) a concomitant IO. A post hoc power analysis based on the primary research question with an alpha of 0.05 and a beta error of 0.20 revealed a minimal detectable difference of 4.6° of flexion. RESULTS After PAO, flexion, IR, and adduction/abduction did not differ from the nondysplastic control hips with the numbers available (p ranging from 0.061 to 0.867). Extension was decreased (19° ± 15°; range, -18° to 30° versus 28° ± 3°; range, 19°-30°; p = 0.017) and ER in 0° flexion was increased (25° ± 18°; range, -10° to 41° versus 38° ± 7°; range, 17°-41°; p = 0.002). Dysplastic hips had a higher prevalence of extraarticular impingement at the anteroinferior iliac spine compared with normal hips (48% [13 of 27 hips] versus 5% [one of 19 hips], p = 0.002). A PAO increased the prevalence of impingement for the femoral head from 30% (eight of 27 hips) preoperatively to 59% (16 of 27 hips) postoperatively (p = 0.027). IR in flexion was decreased in hips with a cam-type deformity compared with those with a spherical femoral head (p values from 0.002 to 0.047 for 95°-120° of flexion). A concomitant IO led to a normalization of ER in extension (eg, 37° ± 7° [range, 21°-41°] of ER in 0° of flexion in hips with concomitant IO compared with 38° ± 7° [range, 17°-41°] in nondysplastic control hips; p = 0.777). CONCLUSIONS Using computer simulation of hip ROM, we could show that the PAO has the potential to restore the typically excessive ROM in dysplastic hips. However, a PAO can increase the prevalence of secondary intraarticular impingement of the aspherical femoral head and extraarticular impingement of the anteroinferior iliac spines in flexion and internal rotation. A cam-type morphology can result in anterior impingement with restriction of IR. Additionally, a valgus hip with high antetorsion can result in posterior impingement with decreased ER in extension, which can be normalized with a varus derotation IO of the femur. However, indication of an additional IO needs to be weighed against its inherent morbidity and possible complications. The results are based on a limited number of hips with a pre- and postoperative CT scan after PAO. Future prospective studies are needed to verify the current results based on computer simulation and to test their clinical importance.