To firstly examine the pain levels during distraction osteogenesis (DO) with lengthening nails (LN) in a large sample. A total of 168 cases underwent DO of the tibia or femur with five different models of LN. Under a standardized medical regime, daily pain levels were noted as nominal rating scale (NRS) score (0–10) during the distraction phase. NRS scores and several potential influence factors (LN model, bone, approach, side, age, gender) were evaluated. The mean distraction length was 39.1 ± 14.4 mm. The average NRS score decreased from postoperative day 1 with 2.84 nonlinearly by 1.03 points (36.3

Purpose: In distraction osteogenesis (DO) of long bones, new bone tissue is distracted to lengthen limbs or reconstruct bone defects. However, mechanical boundary conditions in human application such as arising forces are mainly based on limited empirical data. Our aim was the numerical determination of the callus distraction force (CDF) and the total distraction force (TDF) during DO in the tibia of adults to advance the understanding of callus tissue behavior and optimize DO procedures.Method: We implemented a mathematical model based on an animal experiment to enable the calculation of forces arising while distracting callus tissue, excluding the influence of surrounding soft tissue (muscles, skin etc.). The CDF progression for the distraction period was calculated using the implemented model and varying distraction parameters (initial gap, area, step size, time interval, length). Further, we estimated the CDF based on reported forces in humans and compared the results to our model predictions. In addition, we calculated the TDF based on our CDF predictions in combination with reported resisting forces due to soft tissue presence in human cadavers. Finally, we compared the progressions to in vivo TDF measurements for validation.Results: Due to relaxation, a peak and resting CDF is observable for each distraction step. Our biomechanical results show a non-linear degressive increase of the resting and peak CDF at the beginning and a steady nonlinear increase thereafter. The calculated resting and peak CDF in the tibial metaphysis ranged from 0.00075 to 0.0089 N and 0.22-2.6 N at the beginning as well as 20-25 N and 70-75 N at the end of distraction. The comparison to in vivo data showed the plausibility of our predictions and resulted in a 10-33% and 10-23% share of resting CDF in the total resting force for bone transport and elongation, respectively. Further, the percentage of peak CDF in total peak force was found to be 29-58% and 27-55% for bone transport and elongation, respectively. Moreover, our TDF predictions were valid based on the comparison to in vivo forces and resulted in a degressive increase from 6 to 125 N for the peak TDF and from 5 to 76 N for the resting TDF.Conclusion: Our approach enables the estimation of forces arising due to the distraction of callus tissue in humans and results in plausible force progressions as well as absolute force values for the callus distraction force during DO. In combination with measurements of resisting forces due to the presence of soft tissue, the total distraction force in DO may also be evaluated. We thus propose the application of this method to approximate the behavior of mechanical callus properties during DO in humans as an alternative to in vivo measurements.

Background: In distraction osteogenesis (DO) of long bones, new bone tissue is formed and distracted to lengthen limbs or reconstruct bone defects. However, certain anthropometric quantities relevant for biomechanical modelling of DO are unknown, such as areas where new bone tissue is formed. We developed a novel method to facilitate the determination of these distraction areas (DA), which we applied in the tibia and fibula of adults for longitudinal and transverse DO to advance knowledge of anatomical boundary conditions. Methods: CT data sets of 21 adult human tibiae and 24 fibulae were selected for investigation. Volumetric models were created utilizing image segmentation. The DA for longitudinal DO was determined in a CAD environment using the total bone cross section in the proximal, central and distal diaphysis of the tibia and fibula. Additionally, the medullary canal area was determined in the fibula. Furthermore, we measured the total DA and medullary canal DA for transverse distraction using a longitudinally split fibula with an osteotomy length of 8, 12, 16 and 20 cm. The osteotomy plane was oriented in medial and anteromedial direction. Finally, Spearman analyses were conducted to assess the correlation between bone length and DA. Results: For longitudinal DO, the mean total DAs were 878, 535 and 482 mm(2) in the tibia and 132, 153, 124 mm(2) in the fibula for the proximal, central and distal diaphysis, respectively. Regarding transverse distraction, the mean total DAs for a medial and anteromedial osteotomy plane orientation were 962, 1423, 1868 and 2306 mm(2) as well as 925, 1387, 1844, 2279 mm(2) for an osteotomy length of 8, 12, 16 and 20 cm, respectively. Weak, positive, and non-significant correlations were observed when correlating bone length and DA in the tibia and fibula. Conclusions: Quantification of DAs and hence distracted callus tissue in DO advances anatomical knowledge and improves biomechanical modelling by adding a parameter which cannot be approximated based on bone length. (C) 2020 Elsevier GmbH. All rights reserved.

Background: Three-dimensional (3D) preoperative planning and assisted surgery is increasingly popular in deformity surgery and arthroplasty. Reference ranges for 3D lower limb alignment are needed as a prerequisite for standardized analysis of alignment and preoperative planning in 3D, but are not yet established. Methods: On 60 3D bone models of the lower limbs based on computed tomography data, fifteen parameters per leg were assessed by standardized validated 3D analysis. Distribution parameters and differences between sexes were evaluated. Reference values were generated by adding/subtracting one standard deviation from the mean. Results: Women had a significantly lower mean mechanical lateral distal femoral angle compared with men (86.4 +/- 2.1 degrees vs. 87.8 +/- 2.0 degrees; P < .05) and significantly lower mean joint line convergence angle (-2.5 +/- 1.4 degrees vs. -1.3 +/- 1.2; P < .01), but higher mean hip knee ankle angle (178.9 +/- 1.9 degrees vs. 177.8 +/- 23 degrees; P < .05) and mean femoral torsion (182 +/- 9.5 degrees vs. 13.2 +/- 6.4 degrees: P < .05), resulting in a tendency towards valgus alignment and vice versa for men. Differences in mean medial proximal tibial angle were not significant. The mean mechanical axis deviation from the tibial knee joint center was 6.9 +/- 7.3 mm medial and 1.4 +/- 16.1 mm ventral without significant differences between sexes. Conclusions: We describe total and sex-related reference ranges for all alignment relevant axes and joint angles of the lower limb. There are sex-related differences in certain alignment parameters, which should be considered in analysis and surgical planning. (C) 2019 Elsevier B.V. All rights reserved.

INTRODUCTION:Intramedullary nailing is a valuable treatment option for many types of fractures. Furthermore nailing is applicable for osteosynthesis following osteotomy in deformity correction. For intraoperative fine-tuning of alignment in intramedullary (IM) nailing procedures, a bending device for customization of IM nails under sterile conditions was developed. We have performed a retrospective clinical study to analyze and describe the technical requirements, indications and limitations for intraoperative customization of IM nails. MATERIALS AND METHODS:In 41 cases of deformity correction with IM nailing, we applied intraoperative sterile bending of IM nails. The patient age ranged from 13 to 64 years. We evaluated the radiological outcome (precision of the intervention) of 31 completed cases, comparing the preoperative planning with the final result on long-standing radiographs (LSR). The diameter of the nails ranged from 8,5mm to 13mm. Cases with fracture or non-union treatment with intraoperative application of the bending device were excluded and analyzed separately. RESULTS:All removed implants were examined - none of them showed any signs of material fatigue. The amount of intraoperative bending of the nails was 1° to 12°. A high level of precision was achieved, with a median postoperative axis deviation to the preoperative planning of 3,5mm. In a polio patient with limited bone quality, the implant removal caused an undisplaced cortical crack. There were no other complications. There was uneventful and fast bone healing in all patients. CONCLUSIONS:Intraoperative customization of intramedullary nails is a valuable technique for precise alignment control with IM nailing. With this technique, the benefits of IM nailing can be used for a wide range of indications, including deformity correction. The sterile bending device is safe and easy to handle. It is strong enough to bend all commercially available IM nails. Monofocal or linear bending in multiple planes is possible. However, when defining the site of bending, one must consider the removal of the implant in the future.

Chirurgische Simulatoren kommen neben klassischen Tiermodellen und Humanpräparaten zunehmend als attraktive Alternative zur klinischen Ausbildung zum Einsatz. Chirurgische Simulationstechnologie ist typischerweise darauf ausgelegt, chirurgisch-technische Fertigkeiten zu vermitteln („task trainer“). Das Simulatortraining in der Chirurgie beschränkt sich daher auf die individuelle Ausbildung des Chirurgen und berücksichtigt die Beteiligung des restlichen OP-Teams nicht. Das Ziel des Projektes „Assessment and Training of Medical Experts based on Objective Standards“ (ATMEOS) ist die Entwicklung einer immersiven simulierten OP-Umgebung, die es ermöglicht, multidisziplinäre OP-Teams zu trainieren und deren Leistung unter verschiedenen Bedingungen zu bewerten. Hierbei findet ein Mixed-reality-Ansatz Anwendung, der ein synthetisches Patientenmodell, reale chirurgische Instrumente und strahlungsfreies virtuelles Röntgen zur Simulation von Wirbelsäuleneingriffen kombiniert. In vorangegangenen Forschungsarbeiten wurde das Konzept hinsichtlich Realitätstreue, Plausibilität und Immersivität evaluiert. In der aktuellen Forschung werden Metriken zur Bewertung technischer und nichttechnischer Fähigkeiten entwickelt und evaluiert. Ziel ist, in der simulierten OP-Umgebung multidisziplinäre OP-Teams bei minimalinvasiven Eingriffen an der Wirbelsäule zu beobachten sowie die Leistung der einzelnen Teammitglieder und des gesamten Teams objektiv zu bewerten. Zusätzlich können die Effektivität von Trainingsmethoden und Operationstechniken oder erfolgskritische Faktoren, z. B. der Umgang mit Krisensituationen, in der kontrollierten Umgebung erfasst und objektiv bewertet werden.

Trotz großer Fortschritte in der Entwicklung der Hard- und Software von Navigationssystemen finden diese aufgrund ihrer vermeintlichen Komplexität, umständlichen Integration in klinische Arbeitsabläufe und fraglichen Vorteilen gegenüber konventionellen bildgebenden Verfahren bisher wenig Einsatz in den heutigen Operationssälen.

either two 6.5mm cancellous, four 3.5mm cortical lag screws or 3.5mmLCP proximal lateral tibia plate, preliminary compression by a reduction clamp (n =5per group). Interfragmentary compressionwas measured by a pressure sensor film after instrumentation. A one-way analysis of variance (ANOVA)with Bonferroni post hoc correctionwas performed for statistical analysis (p <0.05). Results: Two 6.5mm cancellous lag screws achieved significantly higher compression in non-osteoporotic (2.1±0.6MPa) compared to osteoporotic (0.8±0.2MPa, p <0.01) surrogate bone. Using four 3.5mm cortical lag screws, compression was not significantly different in-between the non-osteoporotic (1.7±0.7MPa) and osteoporotic group (1.4±0.5MPa, p = 1.0), but significantly higher compared to locking plate fixation (non-osteoporotic 0.5±0.1MPa, p <0.01; osteoporotic 0.5±0.1MPa, p = 0.03; plate groups p =1.0). Conclusion: The two6.5mmcancellous screw technique is especially suited for young human non-osteoporotic bone, whereas the four 3.5mm cortical screw configuration could also be applied in osteoporotic bone. A certain amount of compression necessary to avoid a plateau widening and maintain reduction was also achieved by angle stable locking plates, if they are preliminary compressed by a reduction clamp.

Die intraoperative Anwendung von „augmented reality“ (AR, erweiterte Realität) fand bisher überwiegend im Bereich der Endoskopie statt. Dabei wurde das Kamerabild des Endoskops mittels aufwendig errechneter Darstellungen präoperativer Bildgebung erweitert. Aufgrund des hohen Aufwands und der Komplexität der Systeme hat sich die Technologie bisher nicht durchsetzen können. Der „Camera Augmented Mobile C-arm“ (CamC), der einen herkömmlichen C-Bogen durch eine Videokamera erweitert, zeichnet sich durch eine unkomplizierte Handhabung aus. Er bettet das Röntgenbild geometrisch exakt in das Videolivebild ein. Die klinische Anwendung in 43 Fällen zeigte die Stärken des Gerätes bei der Positionierung, der Inzisionsplanung, der Kirschner-Drahteinbringung und der Instrumentenführung anhand der neuartigen Visualisierung. Aufgrund der neuen Funktionen und der einfachen Integration in jeden Eingriff, der einen Bildwandler benötigt, hat der CamC ein großes Potential, die erste AR-Technologie in der Unfallchirurgie und Orthopädie zu werden.

The intraoperative application of augmented reality (AR) has so far mainly taken place in the field of endoscopy. Here, the camera image of the endoscope was augmented by computer graphics derived mostly from preoperative imaging. Due to the complex setup and operation of the devices, they have not yet become part of routine clinical practice. The Camera Augmented Mobile C-arm (CamC) that extends a classic C-arm by a video camera and mirror construction is characterized by its uncomplicated handling. It combines its video live stream geometrically correct with the acquired X-ray. The clinical application of the device in 43 cases showed the strengths of the device in positioning for X-ray acquisition, incision placement, K-wire placement, and instrument guidance. With its new function and the easy integration into the OR workflow of any procedure that requires X-ray imaging, the CamC has the potential to become the first widely used AR technology for orthopedic and trauma surgery.

There are several well established scores for the assessment of the prognosis of major trauma patients that all have in common that they can be calculated at the earliest during intensive care unit stay. We intended to develop a sequential trauma score (STS) that allows prognosis at several early stages based on the information that is available at a particular time.

Several image guided surgery systems were introduced in the research community throughout the past decades. Only a few have found their way into the operating room and even a smaller number of them into everyday clinical routine. Within this paper, we describe a method for workflow based preclinical assessment of image guided surgery systems. This analysis can reveal surgical phase-related strengths and weaknesses of the system that can lead to design changes potentially leveraging future clinical acceptance. The method is based on a workflow analysis of the clinical procedure and the conduction of carefully designed surgery simulations resulting in a quantitative comparison of the current and the newly proposed system. The method was applied to assess the performance of the camera augmented mobile C-arm (CamC), which extends a standard mobile X-ray system by a video camera and provides an overlay of video and x-ray image without any online calibration or registration. This system was applied on several real-world and simulated vertebroplasty procedures and compared to conventional fluoro CT guided interventions. The analysis of these simulations provides initial quantitative results and a comparison of the current clinical method and the new system in terms of duration, X-ray exposure, and changes in the workflow.

OBJECTIVE:Nowadays, the occurrence of brown tumor lesions or osteitis fibrosa cystica caused by long-lasting primary hyperparathyroidism are very rare, since measuring serum calcium became available routinely in the mid-1970s. It is a tumor-like lesion that may affect the entire skeleton, often presenting with diffuse focal bone pain or by pathological fracture.METHODS:We describe our experience of brown tumor lesions at different skeletal sites that were treated at our trauma centre within the last two years. This included surgical therapy for the indications (i) pain at the pelvis, (ii) increased risk for pathological fracture at the tibia and (iii) acute radicular symptoms at the lumbar spine. The literature was reviewed for the current understanding of the pathophysiology as well as therapy of brown tumor lesions in primary hyperparathyroidism.RESULTS:Curettage of a left-sided iliac crest brown tumor terminated focal pain. A less invasive stabilisation system and bone cement decreased both patient pain and the fracture risk of brown tumor lesion sites of the shinbone; and internal fixator including laminectomy at the lumbar spine ended radicular symptoms.CONCLUSION:Patients with refractory primary hyperparathyroidism should be monitored closely by endocrinologists and the patient's serum calcium level should be adjusted as far as possible. Radiography is required only if focal bone pain or pathological fractures or radicular symptoms occur. Surgery should be considered if large bone defects with spontaneous fracture risk or increasing pain are present. Tumor curettage, Palacos plombage and less invasive stabilisation systems have proved to be acceptable surgical options.

BACKGROUND:The purpose of this study was to evaluate the value of C-arm CT imaging of the distal radius with standard patient positioning in intraoperative assessment of plate osteosynthesis. MATERIALS AND METHODS:Four complete distal radius specimens from human cadavers were fractured (type C), and internal fixation with palmar plates (stainless steel) was then carried out in each. On the basis of C-arm fluoroscopy, radiography and C-arm CT (Siremobil Iso-C3D, scans with forearm bones positioned parallel to the z-axis), 19 observers subsequently evaluated the positions of screws near the joint and any steps within the joint, after which the bones were surgically exposed and the imaging results checked against direct visual observations. RESULTS:No statistically significant differences were detected either between the modalities or between the evaluator groups. CONCLUSION:With standard patient positioning, the performance of C-arm CT was equivalent to and not better than that of current standard procedures, i.e. intraoperative fluoroscopy and postoperative radiography. Further studies should examine whether this holds true in clinical practice with representative patient collectives when titanium implants are used and/or optimized patient positioning is practised.

Objective:Nowadays, the occurrence of brown tumor lesions or osteitis fibrosa cystica caused by long-lasting primary hyperparathyroidism are very rare, since measuring serum calcium became available routinely in the mid-1970s. It is a tumor-like lesion that may affect the entire skeleton, often presenting with diffuse focal bone pain or by pathological fracture. Methods:We describe our experience of brown tumor lesions at different skeletal sites that were treated at our trauma centre within the last two years. This included surgical therapy for the indications (i) pain at the pelvis, (ii) increased risk for pathological fracture at the tibia and (iii) acute radicular symptoms at the lumbar spine. The literature was reviewed for the current understanding of the pathophysiology as well as therapy of brown tumor lesions in primary hyperparathyroidism. Results:Curettage of a left-sided iliac crest brown tumor terminated focal pain. A less invasive stabilisation system and bone cement decreased both patient pain and the fracture risk of brown tumor lesion sites of the shinbone; and internal fixator including laminectomy at the lumbar spine ended radicular symptoms. Conclusion:Patients with refractory primary hyperparathyroidism should be monitored closely by endocrinologists and the patient’s serum calcium level should be adjusted as far as possible. Radiography is required only if focal bone pain or pathological fractures or radicular symptoms occur. Surgery should be considered if large bone defects with spontaneous fracture risk or increasing pain are present. Tumor curettage, Palacos ® plombage and less invasive stabilisation systems have proved to be acceptable surgical options.

Zielsetzung: Material und Methoden: Ergebnisse: Schlussfolgerung: Purpose: Materials and Methods: Results: Conclusion:

The pedicle approach for minimally invasive spinal interventions remains an interesting surgical task even after a decade of image-guided surgery in the spine, which has lead to a variety of computer-aided techniques using different imaging modalities We present the first clinical application of CAMC, a novel augmented reality (AR) system and our initial experience with imaging of the pedicle approach. Augmented reality is a technique that superimposes acquired patient data e.g. intra-operative imaging data in-situ. This means the imaging data is merged spatially registered with the real view of the region of interest. This creates an intuitive and ergonomic surgical navigation system that enhances minimally invasive procedures.