Fracture reduction and screw position after 3D-navigated and conventional fluoroscopy-assisted percutaneous management of acetabular fractures: a retrospective comparative study.

BACKGROUND: Navigational techniques in orthopaedic trauma surgery have developed over the last years leaving the question of really improving quality of treatment. Especially in marginal surgical indications, their benefit has to be evident. The aim of this study was to compare reduction and screw position following 3D-navigated and conventional percutaneous screw fixation of acetabular fractures. The study hypothesis postulated that better fracture reduction and better screw position are obtained with 3D navigation. MATERIALS AND METHODS: Preoperative and postoperative CT scans of 37 acetabular fractures treated by percutaneous screw fixation (24 3D-navigated, 13 conventional) were evaluated. Differences in pre- and postoperative fracture gaps and steps were compared in all reconstructions as well as the screw position relative to the joint and the fracture. RESULTS: The differences in fracture gaps and fracture steps with and without 3D navigation were not significantly different. Distance of the screw from the joint line, angle difference between screw and ideal angle relative to the fracture line, length of the possible corridor used and position of the screw thread did not show any significant differences. CONCLUSION: Comparison of 3D-navigated and conventional percutaneous surgery of acetabular fractures on the basis of pre- and postoperative CTs revealed no significant differences in terms of fracture reduction and screw position.

Keeping the driver in the loop through semi-automated or manual lane changes in conditionally automated driving.

In the current study we investigated if drivers of conditionally automated vehicles can be kept in the loop through lane change maneuvers. More specifically, we examined whether involving drivers in lane-changes during a conditionally automated ride can influence critical take-over behavior and keep drivers' gaze on the road. In a repeated measures driving simulator study (n = 85), drivers drove the same route three times, each trial containing four lane changes that were all either (1) automated, (2) semi-automated or (3) manual. Each ride ended with a critical take-over situation that could be solved by braking and/or steering. Critical take-over reactions were analyzed with a linear mixed model and parametric accelerated failure time survival analysis. As expected, semi-automated and manual lane changes throughout the ride led to 13.5% and 17.0% faster maximum deceleration compared to automated lane changes. Additionally, semi-automated and manual lane changes improved the quality of the take-over by significantly decreasing standard deviation of the steering wheel angle. Unexpectedly, drivers in the semi-automated condition were slowest to start the braking maneuver. This may have been caused by the drivers' confusion as to how the semi-automated system would react. Additionally, the percentage gaze off-the-road was significantly decreased by the semi-automated (6.0%) and manual (6.6%) lane changes. Taken together, the results suggest that semi-automated and manual transitions may be an alarm-free instrument which developers could use to help maintain drivers' perception-action loop and improve automated driving safety.

The role of surgery and lithotripsy in childhood urolithiasis.

From 1982 through 1993 36 interventions in 32 infants and children with urolithiasis have been performed in our department. There were 22 boys and 10 girls. The main cause for the interventions have been congenital malformations in 9, followed by recurrent urinary tract infections in 6, previous operations in 5 and hypercalciuria in 5 patients. In 7 children the cause of the urolithiasis remained unknown. As a therapeutic option extracorporeal shock-wave lithotripsy (ESWL) was available after 1988. The malformations as well as the postoperative conditions have been corrected surgically and the calculi were removed at the same time. For post-infectious, idiopathic or hypercalciuric calculi ESWL was used in the majority of patients after 1988. Therefore a total of 26 calculi were removed by operation and 13 by ESWL. Only 1 calculus was extracted endoscopically. There were no complications either after ESWL or after open surgery. Our results show that ESWL gains more and more importance in infants and children. Calculi in congenital malformations or as result of operations are still removed by open surgery. In the other cases ESWL is the method of choice.

T stage and functional outcome in oral and oropharyngeal cancer patients.

BACKGROUND: The locus and extent of resection and the type of reconstruction used in surgery are important joint determinants of functional outcome in oral and oropharyngeal cancer patients. However, prediction of functional outcome from broader factors such as clinical T stage and approximate locus of resection is important for the preoperative period when the extent of resection and the exact surgical reconstruction to be used may not be decided and preoperative counseling about potential functional outcomes is needed. METHODS: Oropharyngeal swallow efficiency (OPSE) and conversational speech understandability (CU) were measured preoperatively and 3 months posthealing in 68 patients. Analysis of variance (ANOVA) was used to determine whether clinical T stage and planned surgical locus were significantly related to these two functional measures, and discriminant analysis was used on the data obtained at 3 months to determine how well CU and liquid OPSE jointly relate to the T stages. RESULTS: In patients with a planned oral tongue locus of resection, significant differences were found at 3 months posthealing on both CU and liquid OPSE between stages T1 -T2 and T3 and between T1-T2 and T4. In patients with a planned oropharynx locus of resection, significant differences were found only on CU at 3 months. These occurred between T1-T2 and T4 and between T3 and T4. Discriminant analysis classified into the correct T stages 70% of T1-T2 and 75% of T4 stage patients, but only 28% of T3 stage patients. However, the T3-stage patients who were misclassified as T4 had significantly larger mean percent of oral tongue resected than those T3 stage patients who were misclassified as T1-T2. CONCLUSIONS: These results are useful for the preoperative counseling of patients with clinical T stages 1-2 and 4. The relationship between T stage and postsurgical function found here is stronger than reported by previous authors, but is still very general.