Minimally invasive surgery when treating endometriosis has a positive effect on health and on quality of work life of affected women.

STUDY QUESTION: What is the effect of the minimally invasive surgical treatment of endometriosis on health and on quality of work life (e.g. working performance) of affected women? SUMMARY ANSWER: Absence from work, performance loss and the general negative impact of endometriosis on the job are reduced significantly by the laparoscopic surgery. WHAT IS KNOWN ALREADY: The benefits of surgery overall and of the laparoscopic method in particular for treating endometriosis have been described before. However, previous studies focus on medical benchmarks without including the patient's perspective in a quantitative manner. STUDY DESIGN, SIZE, DURATION: A retrospective questionnaire-based survey covering 211 women with endometriosis and a history of specific laparoscopic surgery in a Swiss university hospital, tertiary care center. Data were returned anonymously and were collected from the beginning of 2012 until March 2013. PARTICIPANTS/MATERIALS, SETTING, METHODS: Women diagnosed with endometriosis and with at least one specific laparoscopic surgery in the past were enrolled in the study. The study investigated the effect of the minimally invasive surgery on health and on quality of work life of affected women. Questions used were obtained from the World Endometriosis Research Foundation (WERF) Global Study on Women's Health (GSWH) instrument. The questionnaire was shortened and adapted for the purpose of the present study. MAIN RESULTS AND THE ROLE OF CHANCE: Of the 587 women invited to participate in the study, 232 (232/587 = 40%) returned the questionnaires. Twenty-one questionnaires were excluded due to incomplete data and 211 sets (211/587 = 36%) were included in the study. Our data show that 62% (n = 130) of the study population declared endometriosis as influencing the job during the period prior to surgery, compared with 28% after surgery (P < 0.001). The mean (maximal) absence from work due to endometriosis was reduced from 2.0 (4.9) to 0.5 (1.4) hours per week (P < 0.001). The mean (maximal) loss in working performance after the surgery averaged out at 5.7% (12.6%) compared with 17.5% (30.5%) before this treatment (P < 0.001). LIMITATIONS, REASONS FOR CAUTION: The mediocre response rate of the study weakens the representativeness of the investigated population. Considering the anonymous setting a non-responder investigation was not performed. A bias due to selection, information and negativity effects within a retrospective survey cannot be excluded, although study-sensitive questions were provided in multiple ways. The absence of a control group (sham group; e.g. patients undergoing specific diagnostic laparoscopy without treatment) is a further limitation of the study. WIDER IMPLICATIONS OF THE FINDINGS: Our study shows that indicated minimally invasive surgery has a clear positive effect on the wellbeing and working performance of women suffering from moderate to severe endometriosis. Furthermore, national net savings in indirect costs with the present number of surgeries is estimated to be €10.7 million per year. In an idealized setting (i.e. without any diagnosis delay) this figure could be more than doubled. STUDY FUNDING/COMPETING INTERESTS: The study was performed on behalf of the University Hospital of Bern (Inselspital) as one of the leading Swiss tertiary care centers. The authors do not declare any competing interests.

[Bone tissue engineering. Reconstruction of critical sized segmental bone defects in the ovine tibia]. / Knochen-Tissue-Engineering. Rekonstruktion segmentaler Knochendefekte kritischer Größe in der Schafstibia.

Well-established therapies for bone defects are restricted to bone grafts which face significant disadvantages (limited availability, donor site morbidity, insufficient integration). Therefore, the objective was to develop an alternative approach investigating the regenerative potential of medical grade polycaprolactone-tricalcium phosphate (mPCL-TCP) and silk-hydroxyapatite (silk-HA) scaffolds.Critical sized ovine tibial defects were created and stabilized. Defects were left untreated, reconstructed with autologous bone grafts (ABG) and mPCL-TCP or silk-HA scaffolds. Animals were observed for 12 weeks. X-ray analysis, torsion testing and quantitative computed tomography (CT) analyses were performed. Radiological analysis confirmed the critical nature of the defects. Full defect bridging occurred in the autograft and partial bridging in the mPCL-TCP group. Only little bone formation was observed with silk-HA scaffolds. Biomechanical testing revealed a higher torsional moment/stiffness (p < 0.05) and CT analysis a significantly higher amount of bone formation for the ABG group when compared to the silk-HA group. No significant difference was determined between the ABG and mPCL-TCP groups. The results of this study suggest that mPCL-TCP scaffolds combined can serve as an alternative to autologous bone grafting in long bone defect regeneration. The combination of mPCL-TCP with osteogenic cells or growth factors represents an attractive means to further enhance bone formation.

Computational investigations of mechanical failures of internal plate fixation.

This paper investigated the biomechanics of two clinical cases of bone fracture treatments. Both fractures were treated with the same locking compression plate but with different numbers of screws as well as different plate materials. The fracture treated with 12 screws (rigid fixation) failed at 7 weeks with the plate breaking; the fracture with six screws (flexible fixation) endured the entire healing process. It was hypothesized that the plate failure in the unsuccessful case was due to the material fatigue induced by stress concentration in the plate. As the two clinical cases had different fracture locations and different plate materials, finite element simulations were undertaken for each fractured bone fixed by both a rigid and a flexible method. This enabled comparisons to be made between the rigid and flexible fixation methods. The fatigue life was assessed for each fixation method. The results showed that the stress in the rigid fixation methods could be significantly higher than that in flexible fixation methods. The fatigue analyses showed that, with the stress level in flexible fixation (i.e. with fewer screws), the plate was able to endure 2000 days, and that the plate in rigid fixation could fail by fatigue fracture in 20 days. The paper concludes that the rigid fixation method resulted in serious stress concentrations in the plate, which induced fatigue failure. The flexible fixation gave sufficient stability and was better for fracture healing.

Quantitative fit assessment of tibial nail designs using 3D computer modelling.

Intramedullary nailing is the standard fixation method for displaced diaphyseal fractures of the tibia in adults. The bends in modern tibial nails allow for an easier insertion, enhance the 'bone-nail construct' stability, and reduce axial malalignments of the main fragments. Anecdotal clinical evidence indicates that current nail designs do not fit optimally for patients of Asian origin. The aim of this study was to develop a method to quantitatively assess the anatomical fitting of two different nail designs for Asian tibiae by utilising 3D computer modelling. We used 3D models of two different tibial nail designs (ETN (Expert Tibia Nail) and ETN-Proximal-Bend, Synthes), and 20 CT-based 3D cortex models of Japanese cadaver tibiae. With the aid of computer graphical methods, the 3D nail models were positioned inside the medullary cavity of the intact 3D tibia models. The anatomical fitting between nail and bone was assessed by the extent of the nail protrusion from the medullary cavity into the cortical bone, in a real bone this might lead to axial malalignments of the main fragments. The fitting was quantified in terms of the total surface area, and the maximum distance by which the nail was protruding into the cortex of the virtual bone model. In all 20 bone models, the total area of the nail protruding from the medullary cavity was smaller for the ETN-Proximal-Bend (average 540 mm(2)) compared to the ETN (average 1044 mm(2)). Also, the maximum distance of the nail protruding from the medullary cavity was smaller for the ETN-Proximal-Bend (average 1.2mm) compared to the ETN (average 2.7 mm). The differences were statistically significant (p<0.05) for both the total surface area and the maximum distance measurements. By utilising computer graphical methods it was possible to conduct a quantitative fit assessment of different nail designs. The ETN-Proximal-Bend shows a statistical significantly better intramedullary fit with less cortical protrusion than the original ETN. In addition to the application in implant design, the developed method could potentially be suitable for pre-operative planning enabling the surgeon to choose the most appropriate nail design for a particular patient.

Current concepts in tibial plateau fractures.

Tibial plateau fractures can range from a simple lateral split pattern to very complex bicondylar injuries that can be a sour- ce of great disability. these fractures can provide a challenge for both junior as well as for senior surgeons alike. careful evaluation of the mechanism of injury and fracture pattern plays a crucial part in the operative planning. Assessment of the soft tissues should be performed carefully and adequate imaging is mandatory to allow a more detailed evaluation of the fracture architecture and pre-operativeplanning. Timely accurate reduction and fixation is the goal. Over the last decade the surgical approach chosen has been largely determined by the fracture pattern. Internal plate osteosynthesis through antero-lateral and postero-medial incisions is the most commonly utilised technique for complex bi-condylar fractures. An early range of motion with special attention to full knee extension is essential for a successful functional outcome. Application of the principles mentioned is a pre-requisite to achieve the best result. New fixation techniques, such as locking plates, have not changed those principles but helped to apply them more reliably.