Challenges in the interdisciplinary treatment of leakages after left-sided colorectal surgery: endoscopic negative pressure therapy, open-pore film drainage therapy and beyond.

PURPOSE: The treatment of anastomotic leakage after left colorectal surgery remains challenging. Since its introduction, endoscopic negative pressure therapy (ENPT) has proven to be advantageous, reducing the necessity of surgical revision. The aim of our study is to present our experience with endoscopic treatment of colorectal leakages and to identify potential factors influencing treatment outcome. METHODS: Patients who underwent endoscopic treatment of colorectal leakage were retrospectively analyzed. Primary endpoint was the healing rate and success of endoscopic therapy. RESULTS: We identified 59 patients treated with ENPT between January 2009 and December 2019. The overall closure rate was 83%, whereas only 60% of the patients were successfully treated with ENPT and 23% needed further surgery. The time between diagnosis of leakage and uptake of endoscopic treatment did not influence the closure rate, but patients with chronic fistula (> 4 weeks) showed a significantly higher reoperation rate than those with an acute fistula (94% vs 6%, p = 0.01). CONCLUSION: ENPT is a successful treatment option for colorectal leakages, which appears to be more favorable when started early. Further studies are still needed to better describe its healing potential, but it deserves an integral role in the interdisciplinary treatment of anastomotic leakages.

Development and validation of an algorithm to determine the minimal factors needed for non-invasive measurement of the in vivo primary stability of cementless hip implants.

Aseptic loosening is a frequent cause for revision of endoprosthesis. X-ray examinations like Radio-Stereometry-Analysis (RSA) are among the most widely used in vivo methods for its detection. Nevertheless, this method is not used routinely because of bone marker and related radiation exposure. This work aims at creating a new in vivo concept to detect implant stability measuring micromotions without x-ray and to develop a corresponding algorithm. Based on the assumption of contactless measurement, the input parameters for the algorithm are the distances of each ultrasound sensor to the object (prosthesis and bone) and its position. First, the number of parameters necessary for a precise reconstruction and measurement of micromotions between objects had to be defined. Therefore, the algorithm has been tested with simulations of these parameters. Two experimental measurements, either using contact sensors or ultrasound, were used to prove the accuracy of the algorithm. Simulations indicate a high accuracy with three distances as initial parameters for each object. Contact measurements show precise representation of micromotion, and the contactless measurements show the possibility of detecting various materials with a high resolution. This work lays the foundations for non-invasive detection of micromotions between the implant-bone interface.

How do the geometries of the broach handles relate to the distribution of force and moments in a femoral model?

The continuous improvement of minimally invasive hip endoprostheses surgery comes with a change in geometries of surgery instruments like the broach handles. Consequently, depending on the handles' curvature this results in a deviation between handle and femoral axis. Therefore, this study aimed to prove the influence of different handles' curvatures on the preparation of implant site and acting forces and moments in this process. Five femoral models attached to different handles (double-curved, single-curved, straight) were locked in a drop-weight device with standardize implantation forces and moments and five strokes were measured for each possible combination. Distribution of force and moment components was dependent on the handle's curvature, where the lowest variation from the standard force values was by the straight one (av:15.2% ± 0.5%) and the strongest discrepancies were exhibit by the double-curved one (av:54.3% ± 0.1%.). Moment values have also shown this trend with the lowest variation (12.4%-23.3%) by the straight one and the highest discrepancies (56,6%-90.9%) by the double-curved one. Results show that unguided axial impact introduces unwanted transverse forces and moments into the femur. Therefore, broach handles should be modified accordingly so that minimally invasive surgery remains feasible but unwanted forces or moments can still be compensated.