Second trimester dilation and evacuation: a risk factor for preterm birth?

OBJECTIVE: To evaluate whether second trimester pregnancy termination with dilation and evacuation (D&E) vs induction of labor (IOL) affects subsequent risk of preterm birth. STUDY DESIGN: Our cohort was a retrospective cohort of women undergoing second trimester pregnancy termination for fetal anomalies, fetal death or previable premature rupture of membranes. We analyzed the rates of spontaneous delivery <37 weeks in the first pregnancy following the termination. We also compared preterm birth rates in our cohort with national averages and analyzed by the total number of prior procedures. RESULT: There were 173 women in our cohort. Women who had undergone a D&E (n=130) were less likely to have a subsequent preterm birth (6.9 vs 30.2%; P<0.01). This held true for a low risk subset without obstetric risk factors. There was no statistical difference in preterm birth rates for women who had undergone a D&E as compared with national averages, nor between the rates of preterm birth for women with 0, 1, 2 or 3 or more prior first or second trimester procedures. CONCLUSION: We did not find that D&E was a risk factor for preterm delivery when compared with women with a prior IOL or national rates.

Accurate volumetric measurements of anatomical cavities.

OBJECTIVES: The volumetric assessment of anatomical cavities is of high relevance for various applications in medicine. Based on 3D scanning (i.e., CT) of these cavities, the volume can be determined by counting the volume elements of a segmentation of that cavity. Unfortunately, elements on the boundary of the segmentation require special treatment to obtain accurate volumetric measurements. In this paper, we propose a novel technique that in particular increases the accuracy of the volume estimation for the boundary elements of segmented anatomical objects. METHODS: Based on a 3D segmentation of an anatomical cavity, we recursively subdivide boundary volume elements into a set of simple situations, where the volume can be estimated easily. RESULTS: We performed volumetric measurements on seven datasets of phantom models made of plexiglass (see Fig. 1) scanned by a biplane angiography unit and assessed the quality of our method by comparing the measured volume by our novel method and by the fluid required to fill the phantom cavities. CONCLUSIONS: Our method calculates a significantly more accurate volume of the segmented cavities than previous methods. Nevertheless, it is only slightly more computationally expensive.

[Registration using three-dimensional laser surface scanning for navigation in oral and craniomaxillofacial surgery]. / Registrierung mit dreidimensionaler Oberflächen-Laserscanner-Technik zur Navigation in der Mund-, Kiefer- und Gesichtschirurgie.

INTRODUCTION: Recent innovations in laser scanning technology provide a potentially useful tool for three-dimensional surface registration for image-guided surgery. The purpose of this study is to evaluate the clinical reliability of this technique in oral and maxillofacial surgical procedures using image-guided navigation. METHODS: In an experimental step, a stable anthropomorphic skull model with prelabeled markers was scanned and registered with laser surface scanning (z-touch, BrainLAB) and marker- based algorithms. The registration protocol was then repeated 25-times. Root mean square error (RMSE) and target difference values were compared for their suitability for this application. Twelve patients with different indications for oral and maxillofacial surgery were planned for image-guided surgery using a passive infrared surgical navigation system (VectorVision, BrainLAB). Preoperative computed tomography (CT) scans were carried out with newest 16-line multisclice CT-scanner (Siemens Somatom Sensation 16). The new markerless laser surface scanning technique was applied in all intraoperative patient registrations. Registration error was noted. The clinical application accuracy was determined for anatomical landmark localization deviation. RESULTS: In the experimental protocol a mean registration error (RMSE) or target difference of 1.3 (0.14) or 2.08 (0.49) mm for laser scanning and 0.38 (0.01) or 0.99 (0.15) mm for marker registration was found. The differences for RMSE and target localization were statistically significant (p < 0.005). Furthermore, a strong correlation between RMSE and target difference was found for laser scanning (r = 0.96) and marker registration (r = 0.95). During various clinical procedures involving oral and maxillofacial surgery, the overall error of the registration procedure determined as RMSE was 1.21 (0.34) mm. Intraoperatively, the mean clinical application accuracy was found to be 1.8 (0.5) mm. CONCLUSION: Three-dimensional laser surface scanning technique may be a interesting and useful approach to register the patient for image-guided procedures, particularly during oral and craniomaxillofacial surgery.

Image-guided navigation for minimal invasive approaches in craniomaxillofacial surgery.

The use of minimally invasive procedures in maxillofacial surgery will require new technologies involving surgical navigation and techniques. The aim of our studies is to improve the efficacy of image-guided navigation in combination with endoscopically assisted techniques for minimally invasive craniomaxillofacial procedures. Prospective evaluation was made of all patients who underwent surgical procedures using image-guided navigation. The most common type of operations performed were endoscopically assisted interventions within the paranasal sinuses, fracture treatment, the resection of bone lesions and further miscellaneous interventions. Our experience to date suggest that image-data based techniques are eminently applicable, providing a feasible alternative to conventional surgical treatment.

New virtual system for planning of neuroendoscopic interventions.

OBJECTIVE: The demands on virtual planning systems are increasing, particularly for technically pretentious surgical interventions such as intracranial endoscopy. In this article, a new virtual system for neuroendoscopy (VIVENDI) is presented. The main purpose of this system is to provide support for planning and training in neuroendoscopic interventions. MATERIALS AND METHODS: The software is applied for virtual endoscopic visualization of three-dimensional magnetic resonance datasets, using a clinical magnetic resonance scanner. Rendering is performed on a Hewlett-Packard UNIX workstation. RESULTS: Virtual endoscopy provides a three-dimensional view of the cerebral ventricles, with good visualization of anatomic details. The rendering system used allows the generation of fly-through sequences for the entire ventricular system in real time. Navigation is controlled by mouse movements, and the visualization of the computer-generated intraventricular spaces is adapted to the characteristics of the optical endoscope. CONCLUSIONS: The presented virtual neuroendoscopy system is a promising tool for planning and training in neuroendoscopic procedures. It enables these procedures to be simulated prior to surgery based on the patient's individual anatomy.

[Epidemiology of chronic pain - an investigation in 5 medical practices]. / Epidemiologie chronischer Schmerzen. Eine Befragung in 5 Facharztpraxen in Bochum.

BACKGROUND AND METHODS: The aim of this study was to get more information about the prevalence of chronic pain in different practices of home physicians. 900 patients of five different specialists (general medicine, internal medicine, neurology, orthopaedics, surgery) in the german town Bochum were investigated with a questionnaire about chronic pain. Chronic pain was defined as a continuous or intermittend pain of longer duration than six months. RESULTS: 36% (328 patients) of all investigated patients had chronic pain due to this definition, twice more women than men. The four most frequent localisations of chronic pain were the back, the head, the joints and the legs. 15% of the patients with chronic pain were retired or going to retire due to their chronic pain. Orthopaedics were the most frequent physicians visited in the past. Only 5% of the patients had a psychological therapy and only 1% were treated in a pain clinic. The primary treatment strategies of the chronic pain were physiotherapy and drug therapy. 30% of the patients did not have any pain relieve by the past treatment strategies. CONCLUSION: Patients with chronic pain are a frequent and important problem in practices of home physicians. The high frequency of patients with chronic pain in practices of specialists demonstrates the necessity of a special qualification also on this level of our medical system.

Self-acceptance and disconfirming feedback as influences upon performance of a gross motor skill.

High and low self-acceptance subjects (N= 120) were tested under conditions of disconfirming feedback above and below performance expectancy on a gross motor skill. Subjects in the high and low disconfirming feedback groups received confirming feedback after Trials 1 to 4 and disconfirming feedback after Trials 5 to 10. Discrepant feedback as an experimental manipulation did not affect the performance of either group of subjects. The results are discussed in terms of cognitive dissonance theory.