M. Winkelmann

Development and first clinical application of automated virtual reconstruction of unilateral midface defects

PURPOSE Computer-assisted surgery is used for decision making, treatment, and quality control throughout the reconstruction process of unilateral midface defects. The current approaches exploit the symmetry of the face by mirroring the intact side on the defect side using various segmentation methods. All commercially available implementations, however, are somewhat time consuming and dependent on the level of expertise of the user. We present a method for automatic reconstruction of unilateral midface defects using registration. MATERIAL AND METHODS To reconstruct a skull by registration, the defect volume has to be virtually deleted from the skull. This modified data set is then mirrored and registered onto the original, defect-free skull. The fusion of these two skulls is the virtual reconstructed skull bridging the defect. Reconstruction by registration was performed for 24 different skulls without motion or dental restoration artifacts. Subsequently, simulation was performed with four accurately defined, various-sized, defects of the orbito-zygomatic complex. The results of the automated virtual reconstructions were compared with those obtained for the same defects as determined using conventional atlas-based planning software (iPlan). To simulate various clinical situations, four groups each containing six skulls were evaluated: the complete skull, midface and neurocranium, midface and lower jaw, and midface alone. The differences were compared using the similarity coefficients of Sørensen-Dice and Jaccard. Statistical analyses were performed using the t-test and Mann-Whitney U test. RESULTS The reconstruction results were similar for all the groups. The Sørensen-Dice coefficients of similarity for all reconstructed skulls were 0.869 and 0.874 for the registration and atlas-based reconstructions, respectively. The corresponding Jaccard coefficients were 0.774 and 0.781, respectively. Atlas-based reconstruction showed significantly better results in group 3 (midface and lower jaw) alone. CONCLUSION Virtual automated reconstruction by registration had equivalent accuracy to conventional atlas-based reconstruction across a spectrum of defects, from simple orbital to complex orbito-zygomatic defects. However, for those involving the midface and lower jaw, atlas-based reconstruction showed significantly better results. Although the new approach is somewhat hardware demanding, it is user independent, dispensing with the need for time-consuming adjustments to the results of planning. The first clinical application of registration reconstruction revealed performance equivalent to that of the conventional approach.

Is there a benefit for health care workers in testing HIV, HCV and HBV in routine before elective arthroplasty?

INTRODUCTION Occupational infection of clinical health care workers with blood-borne viruses (BBVs) like human immunodeficiency virus (HIV), hepatitis B virus (HBV) or hepatitis C virus (HCV) is a current and often emotionally discussed issue. HCV and especially HIV are still stigmatized. The consequence is a broad and maybe irrational fear of professional health care workers being infected occupationally. Therefore, we assessed preoperative screening to: (1) answer whether this can detect not previously diagnosed blood-borne virus infections to a great extent, (2) calculate a cost-benefit ratio to find out, if the screenings potential ability to prevent occupational transmission of BBVs to health care workers faces unjustifiable high costs. HYPOTHESIS Preoperative routine screening is limited suitable for enhancement of detecting fomites compared to interview the patient. MATERIALS AND METHODS Retrospective cohort study of preoperative screening for HIV, HBV and HCV (HBsAg, anti-HCV and HIV-Ab/Ag-Combination) for every patient who was admitted to the traumatologic department for elective arthroplasty between 01/01/1997 and 31/12/2008. RESULTS Among the 1534 patients who underwent elective prosthetic surgery [total hip (879) and knee arthroplasty (508), followed by shoulder, elbow and upper ankle joint], 693 (45.2%) patients were male and 841 (54.8) female. Mean age was 64.2±13.8 years. Screening tests were available for 1373 patients (89.5%). Among all screened patients, we found 21 HCV, 10 HBV and 1 HIV infections. 5 HBV (0.5%) and 7 HCV infections (0.7%) were unknown before. Every newly detected infectious patient occasions screening costs about 7250€. Considering this data, the risk of HCV transmission from an index patient with unknown status of infectiousness to health care worker after percutaneous contact to blood is 0.08 ‰ and of HIV transmission is 0.00054 ‰ in our study population. DISCUSSION Routine preoperative screening for BBVs of patients undergoing elective arthroplasty, who were asked for HBV, HCV and HIV, should be reconsidered and is, in times of sparse funds, overpriced. LEVEL OF EVIDENCE IV.

[Accidents in equestrian sports : Analysis of injury mechanisms and patterns].

BACKGROUND Equestrian sports are one of the most popular forms of sport in Germany, while also being one of the most accident-prone sports. Furthermore, riding accidents are frequently associated with a high degree of severity of injuries and mortality. Nevertheless, there are insufficient data regarding incidences, demographics, mechanisms of accidents, injury severity and patterns and outcome of injured persons in amateur equestrian sports. Accordingly, it was the aim of the present study to retrospectively analyze these aspects. METHODS A total of 503 patients were treated in the emergency room of the Hannover Medical School because of an accident during recreational horse riding between 2006 and 2011. The female gender was predominantly affected with 89.5 %. The mean age of the patients was 26.2 ± 14.9 years and women (24.5 ± 12.5 years) were on average younger than men (40.2 ± 23.9 years). A special risk group was girls and young women aged between 10 and 39 years. The overall injury severity was measured using the injury severity score (ISS). RESULTS Based on the total population, head injuries were the most common location of injuries with 17.3 % followed by injuries to the upper extremities with 15.2 % and the thoracic and lumbar spine with 10.9 %. The three most common injury locations after falling from a horse were the head (17.5 %), the upper extremities (17.4 %), the thoracic and lumbar spine (12.9 %). The most frequent injuries while handling horses were foot injuries (17.2 %), followed by head (16.6 %) and mid-facial injuries (15.0 %). With respect to the mechanism of injury accidents while riding were predominant (74 %), while accidents when handling horses accounted for only 26 %. The median ISS was 9.8 points. The proportion of multiple trauma patients (ISS > 16) was 18.1 %. Based on the total sample, the average in-hospital patient stay was 5.3 ± 5.4 days with a significantly higher proportion of hospitalized patients in the group of riding accidents. Fatal cases were not found in this study but the danger of riding is not to be underestimated. The large number of sometimes severe injuries with ISS values up to 62 points can be interpreted as an indication that recreational riding can easily result in life-threatening situations. CONCLUSION Girls and young women could be identified as a group at particular risk. It has been demonstrated in this study that the three most common injury locations after falling from a horse were the head, the upper extremities, the thoracic and lumbar spine. The most frequent injury locations while handling horses were foot injuries, followed by head and mid-facial injuries.

Fractures of the transverse processes of the fourth and fifth lumbar vertebrae in patients with pelvic ring injuries

Aims This study aimed to analyze the correlation between transverse process (TP) fractures of the fourth (L4) and fifth (L5) lumbar vertebrae and biomechanical and haemodynamic stability in patients with a pelvic ring injury, since previous data are inconsistent. Patients and Methods The study is a retrospective matched‐pair analysis of patients with a pelvic fracture according to the modified Tile AO Müller and the Young and Burgess classification who presented to a level 1 trauma centre between January 2005 and December 2014. Results A total of 728 patients with pelvic ring injuries were included, of whom 183 (25.1%) had a biomechanically unstable pelvic fracture. Of these patients, 84 (45.9%) had a fracture of a TP of L4 and/or L5. A total of 73 patients (13.4%) with a stable pelvic ring injury (p < 0.001) had a fracture of a TP. Patients with a fracture of a TP of L4 and/or L5 had a 5.5‐fold risk (odds ratio (OR)) of having a biomechanically unstable pelvic injury. TP fractures (OR 1.6, p = 0.2) could not be confirmed as an independent predictor of haemodynamic instability. Conclusion This is the first study that has demonstrated a positive correlation between a TP fracture of L4 and/or L5 and a biomechanically unstable pelvic ring injury. The presence of transverse process fractures of L4 and/or L5 indicates increased severity of pelvic injury and therefore can help in the planning of emergency treatment.

Radiological and Clinical Outcomes of Balloon Kyphoplasty versus Radiofrequency Kyphoplasty in the Treatment of Vertebral Compression Fractures

Study Design Retrospective cohort analysis Purpose Comparison of balloon kyphoplasty (BKP) and radiofrequency kyphoplasty (RFK) with respect to height restoration of the fractured vertebral bodies and the pain relief experienced after the surgical procedure. Overview of Literature BKP and RFK both offer safe, time-saving, and potent treatment options for vertebral compression fractures, but neither of these methods demonstrated any key advantage over the other yet. Methods We performed a retrospective analysis of a cohort of 156 patients (mean age, 73±11 years) with 252 fractured vertebral bodies treated with kyphoplasty. Pain intensity was measured using a Visual Analogue Scale. Preoperative and postoperative computed tomography images were analyzed and gauged using modified bisegmental Cobb angle, vertebral angle, as well as anterior (Ha), middle (Hm), and posterior (Hp) vertebral body heights. Results The mean postoperative pain relief was 5.1±1.8, which was maintained over the entire follow-up period. There were no significant differences in the pain relief between BKP and RFK. Postoperative changes in the vertebral angle (−1.3°±3.3°, p<0.001) and Ha, Hm, and Hp vertebral body heights (Ha, 1.5±2.9 mm; Hm, 2.1±2.9 mm; Hp, 0.9±2.1 mm; p<0.001) were significant. However, the initial height restoration could not be maintained by the 6-week and 1-year follow-up. Neither BKP nor RFK could achieve a clinically relevant advantage over each other. There was no correlation between pain relief and height restoration after kyphoplasty. Conclusions Both BKP and RFK had comparable beneficial clinical and radiological effects in the treatment of vertebral compression fractures. However, neither the actual extent of height restoration nor its loss seems to affect the marked pain relief.

Unfälle im Reitsport@@@Accidents in equestrian sports: Analyse von Verletzungsmechanismen und -mustern@@@Analysis of injury mechanisms and patterns

BACKGROUND Equestrian sports are one of the most popular forms of sport in Germany, while also being one of the most accident-prone sports. Furthermore, riding accidents are frequently associated with a high degree of severity of injuries and mortality. Nevertheless, there are insufficient data regarding incidences, demographics, mechanisms of accidents, injury severity and patterns and outcome of injured persons in amateur equestrian sports. Accordingly, it was the aim of the present study to retrospectively analyze these aspects. METHODS A total of 503 patients were treated in the emergency room of the Hannover Medical School because of an accident during recreational horse riding between 2006 and 2011. The female gender was predominantly affected with 89.5 %. The mean age of the patients was 26.2 ± 14.9 years and women (24.5 ± 12.5 years) were on average younger than men (40.2 ± 23.9 years). A special risk group was girls and young women aged between 10 and 39 years. The overall injury severity was measured using the injury severity score (ISS). RESULTS Based on the total population, head injuries were the most common location of injuries with 17.3 % followed by injuries to the upper extremities with 15.2 % and the thoracic and lumbar spine with 10.9 %. The three most common injury locations after falling from a horse were the head (17.5 %), the upper extremities (17.4 %), the thoracic and lumbar spine (12.9 %). The most frequent injuries while handling horses were foot injuries (17.2 %), followed by head (16.6 %) and mid-facial injuries (15.0 %). With respect to the mechanism of injury accidents while riding were predominant (74 %), while accidents when handling horses accounted for only 26 %. The median ISS was 9.8 points. The proportion of multiple trauma patients (ISS > 16) was 18.1 %. Based on the total sample, the average in-hospital patient stay was 5.3 ± 5.4 days with a significantly higher proportion of hospitalized patients in the group of riding accidents. Fatal cases were not found in this study but the danger of riding is not to be underestimated. The large number of sometimes severe injuries with ISS values up to 62 points can be interpreted as an indication that recreational riding can easily result in life-threatening situations. CONCLUSION Girls and young women could be identified as a group at particular risk. It has been demonstrated in this study that the three most common injury locations after falling from a horse were the head, the upper extremities, the thoracic and lumbar spine. The most frequent injury locations while handling horses were foot injuries, followed by head and mid-facial injuries.

Injury severity in polytrauma patients is underestimated using the injury severity score: a single-center correlation study in air rescue

PurposePrehospital estimation of injury severity is essential for prehospital therapy, deciding on the destination hospital and the associated emergency room care. The aim of this study was to compare prehospital estimates of the abbreviated injury scale (AIS) and the Injury Severity Score (ISS) by emergency physicians with the values of AIS and ISS of injury severity determined at the conclusion of diagnostics.MethodsIn this prospective study, the ISS was determined prehospital by emergency physicians. The validated AIS and ISS were analyzed based on final diagnoses. A Bland–Altman plot was used in analyzing the agreement between two different assays as well as sensitivity and specificity were determined. Confidence intervals were calculated for a Wilson score. Significance level was set at p ≤ 0.05.ResultsThe prehospital ISS was estimated at 26.0 ± 13.0 and was 34.7 ± 16.3 (p < 0.001) after in-hospital validation. In addition, most of the AIS subgroups were significantly higher in the final calculation than preclinically estimated (p < 0.05). When analyzing subgroups of trauma patients (ISS < 16 vs. ISS ≥ 16), we were able to demonstrate a sensitivity of > 90% to identify a multiple-trauma patient. Diagnosing a higher injury severity group (ISS ≥ 25), sensitivity dropped to 61.1%. The Bland–Altman plot demonstrates that injury severity is underestimated in higher injury levels.ConclusionMultiple-trauma patients can be identified using the ISS. Anatomic scores might be used for transport decisions; however, an accurate estimation of the injury severity should also be based on other criteria such as patient status, mechanism of injury, and other triage criteria.

Connection of a hip prosthesis and an intramedullary nail as a special solution in a subtrochanteric femoral fracture with fibrous dysplasia

Treatment of fractures associated with fibrous dysplasia is difficult because of poor bone quality. In a brief report we present a case in which a hip prosthesis is connected with the distal part of a broken cannulated intramedullary femur nail. Postoperatively, the patient was mobilized with full weight bearing. Radiographs proved the correct position of the implant and a favorable clinical function could be achieved.

Pelvic and Acetabular Trauma

With an incidence of 3–8 % of all fractures, pelvic fractures are relatively rare [1–4]. They range from low-energy stable fractures to high-energy unstable fractures with accompanying soft tissue injuries (complex pelvic trauma). Within polytrauma patients the percentage ascends to 25 %, which is similar to the incidence of pelvic fracture in fatal motor vehicle accidents with 23–25 % [5–7] .

Kinetic therapy in multiple trauma patients with severe blunt chest trauma: An analysis at a level-1 trauma center

BACKGROUND AND OBJECTIVES Chest trauma is a relevant risk factor for mortality after multiple trauma. Kinetic therapy (KT) represents a potential treatment option in order to restore pulmonary function. Decision criteria for performing kinetic therapy are not fully elucidated. The purpose of this study was to investigate the decision making process to initiate kinetic therapy in a well defined multiple trauma cohort. METHODS A retrospective analysis (2000-2009) of polytrauma patients (age > 16 years, ISS ⩾ 16) with severe chest trauma (AIS(Chest) ⩾ 3) was performed. Patients with AIS(Head) ⩾ 3 were excluded. Patients receiving either kinetic (KT+) or lung protective ventilation strategy (KT-) were compared. Chest trauma was classified according to the AIS(Chest), Pulmonary Contusion Score (PCS), Wagner Jamieson Score and Thoracic Trauma Severity Score (TTS). There were multiple outcome parameters investigated included mortality, posttraumatic complications and clinical data. A multivariate regression analysis was performed. RESULTS Two hundred and eighty-three patients were included (KT+: n=160; KT-: n=123). AIS(Chest), age and gender were comparable in both groups. There were significant higher values of the ISS, PCS, Wagner Jamieson Score and TTS in group KT+. The incidence of posttraumatic complications and mortality was increased compared to group KT- (p< 0.05). Despite that, kinetic therapy failed to be an independent risk factor for mortality in multivariate logistic regression analysis. CONCLUSIONS Kinetic therapy is an option in severely injured patients with severe chest trauma. Decision making is not only based on anatomical aspects such as the AIS(Chest), but on overall injury severity, pulmonary contusions and physiological deterioration. It could be assumed that the increased mortality in patients receiving KT is primarily caused by these factors and does not reflect an independent adverse effect of KT. Furthermore, KT was not shown to be an independent risk factor for mortality.