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Curettage is the treatment of choice for enchondromas, the most common primary tumour of the hand. In contrast, additional bone grafting remains controversial. Between 1998 and 2004, we operated on 22 patients with monostotic enchondroma of the hand. Sixteen patients (eight of whom had no additional bone grafting, and eight who had) were evaluated at a mean of 68 (range 42-108) months (no) and 50 (range 29-65) months (bone grafts) postoperatively. Bone density was measured densitometrically on the radiographs, and the groups were compared with each other and within themselves with corresponding locations on the healthy opposite hand. Neither bone density nor functional results were significantly different. Additional bone grafting in the treatment of enchondromas is not necessary and should be reserved for particular indications.

The impact of tele and mobile information technology will increase the need for fast access to geodata significantly in the next years. However, hitherto many problems concerning the wireless access to geodata e.g. to be used in route planning clients are not yet solved. Beside transaction management the requirements of route planning systems to GIS technology mainly concern the modelling and management of graph-based geodata. New challenges to meet are the efficient storage of routes and the supply of location-based database queries. However, today's first commercial database management systems for mobile devices do not support spatial database queries. In this article we collect requirements and present a first implementation prototype of a mobile route planning system focusing on the support of spatial database queries. First experiences with a mobile bicycle route planning client coupled with a database management system are presented. We show that at the server side the computation and storage of different route types as well as the generation of routes under consideration of semantic information like tourist information or roads with certain points of interest should make up the main functionality of such a system. The mobile client should supply database support for the location-based visualization of routes and an offline data management of route data.

The purpose of this study was to examine the efficacy of ultrasound (US)-guided decompression of the myelon in the surgical treatment of spinal fractures. Intraoperative ultrasonography was performed in 22 patients with traumatic stenosis of the spinal canal during spinal cord surgery with removal of retropulsed bony fragments. US imaging requires a posterior approach and an enlarged foramen interarcuale. The posterior vertebral facet and the myelon can accurately be distinguished from small bony fragments by ultrasonography. Pre- and postoperative computed tomography was compared with intraoperative US imaging. Complete decompression of the spinal canal was controlled by US imaging of the restored ventral epidural space, as seen after repositioning of displaced fragments. Thus, the required extent of the surgical procedure was determined by intraoperative ultrasonography. We conclude that intraoperative US imaging is an important tool to monitor the restoration of the spinal canal and decompression of the spinal cord in case of fracture. The repositioning of stenosing bony fragments using surgical instruments can be monitored. US imaging as a real-time method intraoperatively provides the surgeon with additional information and significantly influences treatment options. (E-mail:klaus.lerch@klinik.uni-regensburg.de)

Either an extensor indicis transposition (EIT) or an intercalated free tendon graft (FTG) can be used for secondary reconstruction of the extensor pollicis longus (EPL) tendon. We reviewed 1469 cases of extensor tendons repaired between 1992 and 2003 and compared the results. In only 55 patients was an isolated secondary reconstruction of the EPL done. Forty-five patients (82%) were available for clinical follow-up after a mean of 4.3 (range 2-11) years (28 (62%) who had EIT and 17 (38%) who had FTG). Thumb function was assessed postoperatively using Geldmacher's criteria, and the uninjured thumb served as control. The comparison showed no significant differences between the procedures for the single variables evaluated, or for the injured and other (uninjured) thumb in either group. For isolated secondary reconstruction of the EPL tendon, both the extensor indicis transposition and a free autologous tendon graft successfully restore thumb function. Therefore, both surgical techniques can be considered equal alternatives.

Purpose To address the factors that surgeons use to decide between 2 options for treatment when the evidence is inconclusive. Methods We tested the null hypothesis that the factors surgeons use do not vary by training, demographics, and practice. A total of 337 surgeons rated the importance of 7 factors when deciding between treatment and following the natural history of the disease and 12 factors when deciding between 2 operative treatments using a 5-point Likert scale between "very important" and "very unimportant." Results According to the percentages of statements rated very important or somewhat important, the most popular factors influencing recommendations when evidence is inconclusive between treatment and following the natural course of the illness were "works in my hands," "familiarity with the treatment," and "what my mentor taught me." The most important factors when evidence shows no difference between 2 surgeries were "fewer complications," "quicker recovery," "burns fewer bridges," "works in my hands" and "familiarity with the procedure." Europeans rated "works in my hands" and "cheapest/most resourceful" of significantly greater importance and "what others are doing," "highest reimbursement," and "shorter procedure" of significantly lower importance than surgeons in the United States. Observers with fewer than 10 years in independent practice rated "what my mentor taught me," "what others are doing" and "highest reimbursement" of significantly lower importance compared to observers with 10 or more years in independent practice. Conclusions Surgeons deciding between 2 treatment options, when the evidence is inconclusive, fall back to factors that relate to their perspective and reflect their culture and circumstances, more so than factors related to the patient's perspective, although this may be different for younger surgeons. Clinical relevance Hand surgeons might benefit from consensus fallback preferences when evidence is inconclusive. It is possible that falling back to personal comfort makes us vulnerable to unhelpful commercial and societal influences.

Real time Unmanned Arial Vehicle (UAV) image registration is achieved by stimulating one eye with a live video image from a flying UAV while stimulating the other eye with calculated images. The calculated image is initialized by telemetry signals from the UAV and corrected using the Perspective View Nascent Technology (PVNT) software package model-image feedback algorithm. Live and registered calculated images are superimposed allowing command functions including target geo-location, UAV sensor slewing, tracking, and way point flight control. When the same equipment is used with the naked eye the forward observer function can be implemented to produce accurate target coordinates. The paper will then discuss UAV mission control and forward observer target tracking experiments conducted at Camp Roberts, California.

Execution of course grain parallel programs in PC clusters promises super-computer performance in low cost hardware environments. However the overhead associated with data distribution, synchronization, and peripheral access can easily eliminate any performance gain promised by the individual cluster capacity. Application specific system performance analysis is required both to engineer PC cluster hardware and evaluate the cost effectiveness of parallelizing software components. This paper presents a distributed system performance model and software analysis methodology suitable for estimating the execution times of large grain parallel application programs in clusters of PC hardware. The performance model emphasizes the use of application hardware performance results readily available in most systems. These are combined with single thread application software resource requirements in order to estimate the achievable execution rates in target clusters. A case study of the analysis of a video realistic battlefield simulator implementation in a PC cluster running under Linux is presented. Benchmark results and performance estimates for specific candidate hardware configurations are calculated and compared with actual results.

The article of record as published may be found at http://dx.doi.org/10.1117/12.818225 The problem of real-time image geo-referencing is encountered in all vision based cognitive systems. In this paper we present a model-image feedback approach to this problem and show how it can be applied to image exploitation from Unmanned Arial Vehicle (UAV) vision systems. By calculating reference images from a known terrain database, using a novel ray trace algorithm, we are able to eliminate foreshortening, elevation, and lighting distortions, introduce registration aids and reduce the geo-referencing problem to a linear transformation search over the two dimensional image space. A method for shadow calculation that maintains real-time performance is also presented. The paper then discusses the implementation of our model-image feedback approach in the Perspective View Nascent Technology (PVNT) software package and provides sample results from UAV mission control and target mensuration experiments conducted at China Lake and Camp Roberts, California

This paper describes the requirements, data structures, and algorithms utilized in the run time Player Unit of the OneTESS program. OneTESS is a combined instrumentation suit designed to satisfy the requirements for both training and operational testing being developed by a team lead by AT&T. Specifically we will describe the terrain services and Player Unit services required for geometric pairing and engagement processing along with the accurate database design and procurement strategy required to build it. The paper will also describe a voxel based visualization engine adapted to perform dynamic terrain updates and high accurate test site preparation. We will also describe the process for procuring and testing the fidelity of the terrain environment and describe the analysis to answer the "what is good enough" question within the context of instrumentation accuracies and development strategies. Lastly we will discuss the implications and opportunities afforded by onboard environment models both for future test and training applications as well as in future deployable units.

The ability to rapidly detect and identify potential targets both fixed and mobile from multiple sensor feeds is a critical function in network centric warfare. In this paper we describe the use of Image Differencing and 3D terrain database editing in order to fuse oblique aerial photos, IR sensor imagery, and other non-traditional data sources to produce battlefield metrics that support network centric operations. Such metrics include target detection, recognition, and location, and improved knowledge of the target environment. Key to our approach is the rapid generation of target and background signatures from high-resolution 1-meter object descriptor terrain databases. This technique utilizes the difference between measured and calculated sensor images to 1) update and correct knowledge of the terrain background, 2) register multi sensor imagery 3) identify potential/candidate targets based on residual image differencing and 3) measure and report target locations based on scene matching. The technique is especially suited for utilizing imagery from reconnaissance and remotely piloted vehicle sensors. It also holds promise for automation and real-time data reduction of battlefield sensor feeds and for improving now-time situational awareness. We will present the algorithms and approach utilized in the Image Differencing technique. We will also describe the software developed to implement the approach. Lastly we will present the results of experiments and benchmarks conducted to identify and measure target locations in test locations at Ft. Hood, TX and Ft. Hunter Liggett, CA.

The ability to rapidly and inexpensively generate terrain databases to replicate actual terrain is critical to insuring correlation between the results from live, virtual, and constructive simulations used in testing and evaluating weapons, sensors, and battlefield command and control systems. In this paper we describe a technique for producing battlefield terrain data sets from oblique aerial photos and other nontraditional data sources using image differencing and 3D terrain editing tools. This technique uses a feedback loop to calculate terrain data parameters from differences between actual sensor imagery and synthetic imagery of replicated terrain created by an image generator. The technique is especially well suited for updating knowledge of battlefield situations from reconnaissance and remotely piloted vehicle sensors. It also holds promise for automation and real-time data reduction of battlefield sensor feeds and improved now-time situational awareness. W e will present the algorithms and approach utilized in the Image Differencing technique. We will also describe the software developed to implement the approach. Lastly we will present the results of experiments and benchmarks conducted to measure the effectiveness and progress made toward real-time terrain database generation.

We report the case of a 72-year-old patient with rheumatoid arthritis complicated by spontaneous ruptures of the flexor digitorum superficialis and profundus tendons of the left index finger. Extreme volar-flexed intercalated segment instability resulted in protrusion of the head of the capitate bone into the carpal tunnel and rupture of both tendons caused by wear. Reconstruction of the flexor digitorum profundus tendon, interposition of a tendon graft, and radiolunate arthrodesis restored function.

This paper describes a system, which compares aerial photographs of the same terrain taken at different times and tires to recognize straight-edged cultural features that have changed. This work is intended to be highly robust, handling very different lighting conditions, weather, times of year, camera, and film between the images to be compared. Our system AERICOMP is designed to facilitate battlefield terrain modeling by permitting automatic updates form new images. AERICOMP does coarse registration, image correction, feature detection, automatic refined registration, feature difference detection and reduction, feature difference presentation and operator acceptance, difference identification, and database update. It emphasizes line segments for comparisons because differences in them are more robust for photometric changes between terrain images. In addition, line segment comparisons require less computation than pixel comparisons and are more compatible with identification tasks. For our intended application of battlefield terrain modeling, detecting changes in man-made structures is of much greater importance than changes in vegetation, and line segments are the key to identifying such structures. We show results involving change analysis between color IR and black/white USGS photographs of the same area six years apart. Even a mostly automatic system benefits form user interacting at key points. AERICOMP exploits user judgements at the beginning and end of its processing to assist in coarse registration and to approve the significance of any differences found. AERICOMP is currently under development at the Naval Postgraduate School, and is supported by the TENCAPS project under the US Navy.

By utilizing images calculated on-the-fly as a filter improvements in real-time performance of object measurement and feature extraction can be achieved for automated aerial photograph analysis. The process requires the rapid calculation of images from an existing terrain database. The calculated images are then compared to incoming sensor data. The difference between the calculated and sensor image is then utilized as a parallel error signal for updating the state of knowledge of the objects and features measured. The advantage of this image feedback technique is that the calculation of sensor realistic perspective views from parameterized object models is easier than the direct interpretation of complex images. The feedback technique effectively eliminates what is already known from the measurement signal and thereby reduces the amount of data which must be processed by pattern recognition techniques by orders of magnitude. The paper presents the mathematical description of the image feedback technique and estimates update frame rates which can be expected for real time applications. We then discuss the incremental software development approach and the system design we are using for implementing the technique. The state of the current system is presented along with a discussion of experiments and experiences gained in building large-scale high-resolution terrain databases. The paper concludes by defining future research areas that need to be addressed for improving performance and accuracy.

The problem of rapidly generating accurate object material descriptor databases of the earth's surface has been approached using a quantized rendering transform to code photogrammetric image measurements into physical surface parameters. The approach eliminates the lighting effect inherent in aerial photos which view earth surface elements from different perspectives. It reduces the multi-aspect photographic spectral measurements to objective surface properties which are then used for automated object and surface material classification. This paper presents the algorithms and design for a terrain database creation workstation used to generate 1 meter resolution data. The system was used to digitize approximately 200 aerial photos covering a 400 sq km area of Ft. Hunter Liggett, Calif. and translated into a 1.2 gigabyte surface descriptor database. Included in the workstation is a parallel processing, transputer- based, perspective view generator which uses the rendering transform to calculate side views at real-time rates. The use of this subsystem as a real-time feedback and quality control mechanism during database creation is described and the technique extended to real-time terrain database update systems.

The problem of realistic, high-resolution, earth surface representation for real-time, rendered, video-quality perspective view generation has been approached by using a quantized rendering transform to code image measurements into physical surface modeling descriptors. This paper describes a physical earth surface model and approximates natural light energy scattering equations to derive a transform between photogrammetric measurements and model parameters. This transform was used to translate a 12 Gbyte, photo image, data base covering 400 sq km of Ft. Hunter Liggett, CA into a 1.2 Gbyte surface descriptor file. A prototype transputer-based parallel processing system is also presented. The system uses the rendering transform to calculate real-time perspective views at operator-selectable times, seasons, and environmental conditions. The system produces video-realistic perspective views at a rendering rate of .5 Mpixels/second and is scalable by a factor of 80.© (1993) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.