Haptics in forensics: the possibilities and advantages in using the haptic device for reconstruction approaches in forensic science

Non-invasive documentation methods such as surface scanning and radiological imaging are gaining in importance in the forensic field. These three-dimensional technologies provide digital 3D data, which are processed and handled in the computer. However, the sense of touch gets lost using the virtual approach. The haptic device enables the use of the sense of touch to handle and feel digital 3D data. The multifunctional application of a haptic device for forensic approaches is evaluated and illustrated in three different cases: the representation of bone fractures of the lower extremities, by traffic accidents, in a non-invasive manner; the comparison of bone injuries with the presumed injury-inflicting instrument; and in a gunshot case, the identification of the gun by the muzzle imprint, and the reconstruction of the holding position of the gun. The 3D models of the bones are generated from the Computed Tomography (CT) images. The 3D models of the exterior injuries, the injury-inflicting tools and the bone injuries, where a higher resolution is necessary, are created by the optical surface scan. The haptic device is used in combination with the software FreeForm Modelling Plus for touching the surface of the 3D models to feel the minute injuries and the surface of tools, to reposition displaced bone parts and to compare an injury-causing instrument with an injury. The repositioning of 3D models in a reconstruction is easier, faster and more precisely executed by means of using the sense of touch and with the user-friendly movement in the 3D space. For representation purposes, the fracture lines of bones are coloured. This work demonstrates that the haptic device is a suitable and efficient application in forensic science. The haptic device offers a new way in the handling of digital data in the virtual 3D space.

Finite element 3D reconstruction of the pulmonary acinus imaged by synchrotron X-ray tomography

The alveolated structure of the pulmonary acinus plays a vital role in gas exchange function. Three-dimensional (3D) analysis of the parenchymal region is fundamental to understanding this structure-function relationship, but only a limited number of attempts have been conducted in the past because of technical limitations. In this study, we developed a new image processing methodology based on finite element (FE) analysis for accurate 3D structural reconstruction of the gas exchange regions of the lung. Stereologically well characterized rat lung samples (Pediatr Res 53: 72-80, 2003) were imaged using high-resolution synchrotron radiation-based X-ray tomographic microscopy. A stack of 1,024 images (each slice: 1024 x 1024 pixels) with resolution of 1.4 mum(3) per voxel were generated. For the development of FE algorithm, regions of interest (ROI), containing approximately 7.5 million voxels, were further extracted as a working subunit. 3D FEs were created overlaying the voxel map using a grid-based hexahedral algorithm. A proper threshold value for appropriate segmentation was iteratively determined to match the calculated volume density of tissue to the stereologically determined value (Pediatr Res 53: 72-80, 2003). The resulting 3D FEs are ready to be used for 3D structural analysis as well as for subsequent FE computational analyses like fluid dynamics and skeletonization.

Primary reconstruction of open depressed skull fractures with titanium mesh

Open skull fractures have been traditionally managed in 2 stages: urgent craniotomy and elevation of the fracture with removal of contaminated bone, debridement, and delayed cranioplasty. Primary, single-stage repair of these injures has been said to entail risks such as infections. Recent experience, however, disproved these concerns.We used a primary single-stage reconstruction for patients presenting with open depressed skull fractures. All patients received antibiotic prophylaxis. The patients underwent elevation of the compound fracture and craniotomy if necessary. Debridement was performed, followed by skull reconstruction using a 0.6-mm titanium mesh.We present 5 consecutive male patients (age, 32.2 +/- 15.6 years) who underwent primary reconstruction of open depressed skull fractures. Clinical and radiologic follow-up was performed 2 months after surgery. The duration of the surgery was 2 +/- 1.6 hours. The size of the implanted mesh was 13 +/- 13.1 cm. No infection was detected in our series, with a follow-up period of 22 +/- 6.5 months (range, 16-29 months). The cosmetic result was defined in 4 patients as "excellent" and in 1 patient as "good."Primary reconstruction of open skull fractures with titanium mesh is feasible, safe, and cosmetically preferable than the conventional staged approach. The introduction into clinical practice can be warranted.

Reconstruction of the palatal aponeurosis with autogenous fascia lata in secondary radical intravelar veloplasty: a new method

Velopharyngeal insufficiency in cleft patients with muscular insufficiency detected by nasendoscopy is commonly treated by secondary radical intravelar veloplasty, in which the palatal muscles are reoriented and positioned backwards. The dead space between the retro-displaced musculature and the posterior borders of the palatal bone remains problematic. Postoperatively, the surgically achieved lengthening of the soft palate often diminishes due to scar tissue formation in the dead space, leading to reattachment of the reoriented muscles to the palatal bone and to decreased mobility of the soft palate. To avoid this, the dead space should be restored by a structure imitating the function of the missing palatal aponeurosis. The entire dead space was covered using a double layer of autogenous fascia lata harvested from the lateral thigh, which should allow sufficient and permanent sliding of the retro-positioned musculature. A clinical case of a 9-year-old boy who underwent the operation is reported. Postoperatively, marked functional improvements were observable in speech assessment, nasendoscopy and nasometry. The case reported here suggests that the restoration of the dead space may be beneficial for effective secondary palatal repair. Fascia lata seems to be a suitable graft for this purpose.

Virtopsy -- noninvasive detection of occult bone lesions in postmortem MRI: additional information for traffic accident reconstruction

In traffic accidents with pedestrians, cyclists or motorcyclists, patterned impact injuries as well as marks on clothes can be matched to the injury-causing vehicle structure in order to reconstruct the accident and identify the vehicle which has hit the person. Therefore, the differentiation of the primary impact injuries from other injuries is of great importance. Impact injuries can be identified on the external injuries of the skin, the injured subcutaneous and fat tissue, as well as the fractured bones. Another sign of impact is a bone bruise. The bone bruise, or occult bone lesion, means a bleeding in the subcortical bone marrow, which is presumed to be the result of micro-fractures of the medullar trabeculae. The aim of this study was to prove that bleeding in the subcortical bone marrow of the deceased can be detected using the postmortem noninvasive magnetic resonance imaging. This is demonstrated in five accident cases, four involving pedestrians and one a cyclist, where bone bruises were detected in different bones as a sign of impact occurring in the same location as the external and soft tissue impact injuries.

IDENTIFICATION OF GENES CONTROLLING BIOLOGICAL PROCESSES AND PATHWAYS THROUGH STATISTICAL ANALYSIS AND NETWORK RECONSTRUCTION

The developmental processes and functions of an organism are controlled by the genes and the proteins that are derived from these genes. The identification of key genes and the reconstruction of gene networks can provide a model to help us understand the regulatory mechanisms for the initiation and progression of biological processes or functional abnormalities (e.g. diseases) in living organisms. In this dissertation, I have developed statistical methods to identify the genes and transcription factors (TFs) involved in biological processes, constructed their regulatory networks, and also evaluated some existing association methods to find robust methods for coexpression analyses. Two kinds of data sets were used for this work: genotype data and gene expression microarray data. On the basis of these data sets, this dissertation has two major parts, together forming six chapters. The first part deals with developing association methods for rare variants using genotype data (chapter 4 and 5). The second part deals with developing and/or evaluating statistical methods to identify genes and TFs involved in biological processes, and construction of their regulatory networks using gene expression data (chapter 2, 3, and 6). For the first part, I have developed two methods to find the groupwise association of rare variants with given diseases or traits. The first method is based on kernel machine learning and can be applied to both quantitative as well as qualitative traits. Simulation results showed that the proposed method has improved power over the existing weighted sum method (WS) in most settings. The second method uses multiple phenotypes to select a few top significant genes. It then finds the association of each gene with each phenotype while controlling the population stratification by adjusting the data for ancestry using principal components. This method was applied to GAW 17 data and was able to find several disease risk genes. For the second part, I have worked on three problems. First problem involved evaluation of eight gene association methods. A very comprehensive comparison of these methods with further analysis clearly demonstrates the distinct and common performance of these eight gene association methods. For the second problem, an algorithm named the bottom-up graphical Gaussian model was developed to identify the TFs that regulate pathway genes and reconstruct their hierarchical regulatory networks. This algorithm has produced very significant results and it is the first report to produce such hierarchical networks for these pathways. The third problem dealt with developing another algorithm called the top-down graphical Gaussian model that identifies the network governed by a specific TF. The network produced by the algorithm is proven to be of very high accuracy.

Outcome analysis of breast reconstruction with free transverse rectus abdominis musculocutaneous (TRAM) flaps

QUESTIONS UNDER STUDY: With the reduction in breast cancer mortality in recent years the aesthetic outcome after treatment has gained increasing attention. The aim of this study was to assess the outcome quality of our single institution concept of free TRAM flap breast reconstruction with the aim of providing data to assist the patient's decision-making when breast reconstruction is an option. PRINCIPLES/METHODS: Thirty-two consecutive patients receiving immediate (n = 14) or delayed (n = 18) breast reconstruction with free transverse rectus abdominis musculocutaneous (TRAM) flaps were included. The selection of patients was based on their own wish and the availability of abdominal tissue, without excluding patients at risk for wound healing complications. Patient data were assessed prospectively and the aesthetic outcome was rated after the final result had been achieved. RESULTS: Ten patients sustained wound healing complications (4 of 9 smokers, 8 of 16 patients with a BMI over 25 kg/m2), 8 of them requiring revisional surgery. An average of 1.06 corrective procedures were performed per patient. The aesthetic outcome was judged to be good by 20 patients, fair by 5 and poor by 1 patient who sustained severe tissue loss. CONCLUSIONS: Our results revealed that a large measure of satisfaction is achievable from breast reconstruction with free TRAM flaps, in spite of the invasive nature of the procedure and the inclusion of patients at risk for wound healing complications. These data may be used in the decision-making process by patients eligible for breast reconstruction after mastectomy.

Secondary breast reconstruction with deepithelialized free flaps from the lower abdomen for intractable capsular contracture and maintenance of breast volume

Although surgical techniques and the quality of mammary prostheses have been improved significantly in recent years, capsular contracture attendant on prosthetic mammary reconstruction remains a major flaw. Although rarely, some patients are confronted with recurrent and intractable capsular contractures with resultant breast deformity, even after multiple attempts at capsulectomies and implant exchange. Patients with recurrent capsular contracture often do not want replacement with a new prosthesis, but desire the maintenance of their breast volume with a safe alternative. In an attempt to maintain breast volume and to improve the aesthetic appearance, secondary breast reconstruction using bilateral deepithelialized free flaps from the lower abdomen was performed in a series of seven patients. Three bilateral muscle-sparing TRAM flaps, two bilateral DIEP flaps, one bilateral SIEA flap, one unilateral SIEA flap, and one unilateral DIEP flap (a total number of 14 flaps) were used following implant removal, total capsulectomy, and prophylactic subcutaneous mastectomy. The early postoperative course was uneventful, and all flaps survived completely with no complications. There were no donor-site problems, except in one patient (case 5), who had partial skin necrosis of the abdominal flap. The long-term results (mean follow-up: 4.8 years) demonstrated an aesthetically satisfactory appearance of the breasts, with no major donor-site problems. Several advantages, as well as drawbacks, are highlighted with this technique.