Percutaneous iliosacral screw fixation in S1 and S2 for posterior pelvic ring injuries: technique and perioperative complications

Objective: Percutaneous iliosacral screw placement allows for minimally invasive fixation of posterior pelvic ring instabilities. The objective of this study was to describe the technique for screws in S1 and S2 using conventional C-arm and to evaluate perioperative complications. Methods: Thirty-eight consecutive patients after percutaneous pelvic ring fixation with cannulated screws in S1 and S2 using conventional C-arm fluoroscopy were analysed. Accuracy of screw placement, nerval lesions, need for second surgery, operation time, and time to full weight bearing were assessed postoperatively and during regular follow-up examinations. Results: Twenty-one patients underwent unilateral screw fixation and 17 patients underwent bilateral screw fixation. In total, 83 screws were placed. Mean age of the patients was 52±19years. Mean operation time was 16±7min/screw. Mean follow-up was 5±3months. Time to full weight bearing in 28 patients was 9±4weeks. Eight patients were still not able to support full weight bearing, partially due to concomitant injuries. Patients without concomitant injuries that affected walking were able to bear full weight after 8±4weeks (n=17). Two patients had persistent postoperative hypaesthesia. No motor weakness was apparent and no postoperative bleeding was observed. Secondary surgery due to screw malpositioning or loosening had to be performed in four patients. The presence of a screw in S2 was not indicated for perioperative complications. Conclusions: Percutaneous iliosacral screw fixation is a rapid and definitive treatment for posterior pelvic ring injuries with a low risk of secondary bleeding during posterior pelvic stabilization. The technique using standard C-arm fluoroscopy was also found to be safe for screws placed in S

The calcar screw in angular stable plate fixation of proximal humeral fractures - a case study

<p>Abstract</p> <p>Background</p> <p>With new minimally-invasive approaches for angular stable plate fixation of proximal humeral fractures, the need for the placement of oblique inferomedial screws ('calcar screw') has increasingly been discussed. The purpose of this study was to investigate the influence of calcar screws on secondary loss of reduction and on the occurrence of complications.</p> <p>Methods</p> <p>Patients with a proximal humeral fracture who underwent angular stable plate fixation between 01/2007 and 07/2009 were included. On AP views of the shoulder, the difference in height between humeral head and the proximal end of the plate were determined postoperatively and at follow-up. Additionally, the occurrence of complications was documented. Patients with calcar screws were assigned to group C+, patients without to group C-.</p> <p>Results</p> <p>Follow-up was possible in 60 patients (C+ 6.7 ± 5.6 M/C- 5.0 ± 2.8 M). Humeral head necrosis occurred in 6 (C+, 15.4%) and 3 (C-, 14.3%) cases. Cut-out of the proximal screws was observed in 3 (C+, 7.7%) and 1 (C-, 4.8%) cases. In each group, 1 patient showed delayed union. Implant failure or lesions of the axillary nerve were not observed. In 44 patients, true AP and Neer views were available to measure the head-plate distance. There was a significant loss of reduction in group C- (2.56 ± 2.65 mm) compared to C+ (0.77 ± 1.44 mm; p = 0.01).</p> <p>Conclusions</p> <p>The placement of calcar screws in the angular stable plate fixation of proximal humeral fractures is associated with less secondary loss of reduction by providing inferomedial support. An increased risk for complications could not be shown.</p

Patient-Specific Three-Dimensional Composite Bone Models for Teaching and Operation Planning

Background: Orthopedic trauma care relies on two-dimensional radiograms both before and during the operation. Understanding the three-dimensional nature of complex fractures on plain radiograms is challenging. Modern fluoroscopes can acquire three-dimensional volume datasets even during an operation, but the device limitations constrain the acquired volume to a cube of only 12-cm edge. However, viewing the surrounding intact structures is important to comprehend the fracture in its context. We suggest merging a fluoroscope's volume scan into a generic bone model to form a composite full-length 3D bone model. Methods: Materials consisted of one cadaver bone and 20 three-dimensional surface models of human femora. Radiograms and computed tomography scans were taken before and after applying a controlled fracture to the bone. A 3D scan of the fracture was acquired using a mobile fluoroscope (Siemens Siremobil). The fracture was fitted into the generic bone models by rigid registration using a modified least-squares algorithm. Registration precision was determined and a clinical appraisal of the composite models obtained. Results: Twenty composite bone models were generated. Average registration precision was 2.0mm (range 1.6 to 2.6). Average processing time on a laptop computer was 35s (range 20 to 55). Comparing synthesized radiograms with the actual radiograms of the fractured bone yielded clinically satisfactory results. Conclusion: A three-dimensional full-length representation of a fractured bone can reliably be synthesized from a short scan of the patient's fracture and a generic bone model. This patient-specific model can subsequently be used for teaching, surgical operation planning, and intraoperative visualization purpose

Use of Imatinib in the Prevention of Heterotopic Ossification

Background: Heterotopic ossification (HO) is a common complication following orthopedic and trauma surgery, which may have substantial negative effects on the postoperative outcome. Angiogenesis appears to play a critical role in heterotopic ossification. One of the involved signaling molecules is platelet-derived growth factor (PDGF) which may be inhibited by imatinib. Questions/Purposes: Our goal was to prevent HO by pharmacologically interfering with the molecular signaling pathways involved in the developmental process. We hypothesized that by administering a proven inhibitor of PDGF expression, heterotopic bone formation may be prevented. Methods: The effect of imatinib on HO formation was studied in a murine model which reliably produces islets of HO within the soft tissue following Achilles tenotomy. The control group underwent Achilles tenotomy only. The imatinib group received imatinib mesylate. After trial completion, the limbs were harvested and scanned by micro-CT. Heterotopic bone volume was then identified and quantified. Results: The mean volume of heterotopic bone formed in the control group was 0.976mm3 compared to 0.221mm3 in the imatinib group. The volume of HO in the treatment group was reduced by 85% compared to the control group. Conclusions: The administration of imatinib was associated with a significantly reduced volume of HO. This may be due to the inhibitory effect of imatinib on the PDGF signaling pathway during development of HO. Clinical Relevance: The successful reduction of HO formation following imatinib administration has led to further insight concerning the pathogenesis of HO which in the future may lead to new clinical approaches towards the prevention of H

Whole-body CT in polytrauma patients: effect of arm positioning on thoracic and abdominal image quality

The purpose of this study is to assess the influence of different arm positioning techniques on thoracic and abdominal image quality and radiation dose of whole-body trauma CT (wbCT). One hundred and fifty polytrauma patients (104 male, mean age 47 ± 19) underwent wbCT with arms elevated above the head (group A, n = 50), alongside the abdomen (group B, n = 50), and on a pillow ventrally to the chest with both arms flexed (group C, n = 50). Two blinded, independent observers measured image noise and rated image quality (scores 1-3) of the liver, aorta, spleen, spine, and lower lungs. Radiation dose parameters were noted, and the abdomens' anterior-posterior diameter and scan lengths were measured. Interreader agreements for image noise (r = 0.86; p < 0.001) and subjective image quality (k = 0.71-0.84) were good. Noise was lower (p < 0.05), image quality of the liver, aorta, spleen, and spine was higher, and radiation dose lower in group A than in groups B and C (p < 0.001, each). Image quality of the spleen, liver, and aorta were higher in group C than in group B (p < 0.05, each). No significant differences in scan length (p = 0.61) were found among groups. Abdominal anterior-posterior diameter correlated significantly with noise (r = 0.82; p < 0.01) and dose (r = 0.47; p < 0.001). Estimated effective radiation doses were significantly (p < 0.001) higher in groups B (21.2mSv) and C (21.9mSv) as compared to A (16.1mSv). In wbCT for polytrauma patients, positioning of the arms above the head results in better image quality and lower radiation dose. Placing the flexed arms on a large pillow ventrally to the chest significantly improves image quality as compared to positioning alongside the abdome

Treatment of femoral neck fractures in elderly patients over 60 years of age - which is the ideal modality of primary joint replacement?

BACKGROUND: Femoral neck fractures in the elderly are frequent, represent a great health care problem, and have a significant impact on health insurance costs. Reconstruction options using hip arthroplasty include unipolar or bipolar hemiarthroplasty (HA), and total hip arthroplasty (THA). The purpose of this review is to discuss the indications, limitations, and pitfalls of each of these techniques. METHODS: The Pubmed database was searched for all articles on femoral neck fracture and for the reconstruction options presented in this review using the search terms "femoral neck fracture", "unipolar hemiarthroplasty", "bipolar hemiarthroplasty", and "total hip arthroplasty". In addition, cross-referencing was used to cover articles eventually undetected by the respective search strategies. The resulting articles were then reviewed with regard to the different techniques, outcome and complications of the distinct reconstruction options. RESULTS: THA yields the best functional results in patients with displaced femoral neck fractures with complication rates comparable to HA. THA is beneficially implanted using an anterior approach exploiting the internervous plane between the tensor fasciae latae and the sartorius muscles allowing for immediate full weight-bearing. Based on our findings, bipolar hemiarthroplasty, similar to unipolar hemiarthroplasty, cannot restorate neither anatomical nor biomechanical features of the hip joint. Therefore, it can only be recommended as a second line of defense-procedure for patients with low functional demands and limited live expectancy. CONCLUSIONS: THA is the treatment of choice for femoral neck fractures in patients older than 60 years. HA should only be implanted in patients with limited life expectanc

Augmented reality-based surgical navigation of pelvic screw placement: an ex-vivo experimental feasibility study

BACKGROUND Minimally invasive surgical treatment of pelvic trauma requires a significant level of surgical training and technical expertise. Novel imaging and navigation technologies have always driven surgical technique, and with head-mounted displays being commercially available nowadays, the assessment of such Augmented Reality (AR) devices in a specific surgical setting is appropriate. METHODS In this ex-vivo feasibility study, an AR-based surgical navigation system was assessed in a specific clinical scenario with standard pelvic and acetabular screw pathways. The system has the following components: an optical-see-through Head Mounted Display, a specifically designed modular AR software, and surgical tool tracking using pose estimation with synthetic square markers. RESULTS The success rate for entry point navigation was 93.8%, the overall translational deviation of drill pathways was 3.99 ± 1.77 mm, and the overall rotational deviation of drill pathways was 4.3 ± 1.8°. There was no relevant theoretic screw perforation, as shown by 88.7% Grade 0-1 and 100% Grade 0-2 rating in our pelvic screw perforation score. Regarding screw length, 103 ± 8% of the planned pathway length could be realized successfully. CONCLUSION The novel innovative system assessed in this experimental study provided proof-of-concept for the feasibility of percutaneous screw placement in the pelvis and, thus, could easily be adapted to a specific clinical scenario. The system showed comparable performance with other computer-aided solutions while providing specific advantages such as true 3D vision without intraoperative radiation; however, it needs further improvement and must still undergo regulatory body approval. Future endeavors include intraoperative registration and optimized tool tracking

Reallabore im Kontext transformativer Forschung : Ansatzpunkte zur Konzeption und Einbettung in den internationalen Forschungsstand

Reallabore sind derzeit ein populärer Forschungsansatz an der Schnittstelle zwischen Wissenschaft und Gesellschaft. Neben vermuteten Potentialen, wie der Erzeugung von Transformationswissen und einem Beitrag zu gesellschaftlichem Wandel, gibt es auch vielfältige offene Fragen, u. a. im Hinblick auf das Verhältnis zu transdisziplinärer Forschung, der Übertragbarkeit des erzeugten Wissens oder der Gestaltung von Experimenten in der "realen Welt". Auch eine breit getragene Definition von Reallaboren existiert derzeit nicht. Dieses Diskussionspapier möchte daher dreierlei leisten: Es beginnt mit dem Herausarbeiten von Reallabor-Merkmalen als a) Beitrag zu Transformationsprozessen, b) Experimenten als zentraler Forschungsmethode, c) Transdisziplinarität als Forschungsmodus, d) dem Ziel der Ausweitung und Übertragung der Ergebnisse und e) Reallaboren als Orten wissenschaftlichen und gesellschaftlichen Lernens. Im Nachgang werden diese Merkmale durch Rückbezug auf die einschlägige Literatur vertieft diskutiert. Abschließend werden mit Reallaboren vergleichbare Forschungsansätze (Sustainable Living Labs, Urban Transition Labs und Niche Experiments) im Hinblick auf ihre Ausgestaltung der fünf herausgearbeiteten Merkmale vorgestellt und Reallabore damit in den internationalen Forschungskontext eingebettet. Das Diskussionspapier will damit Forschenden und Praktiker_innen in Reallaboren eine Orientierung ermöglichen. Die vorgestellten konzeptionellen Überlegungen basieren auf einem thematischen Literatur-Review, ebenso wie Diskussionen mit Reallabor- und Transformationsforschenden in nationalen und internationalen Kontexten. Sie sind im Rahmen der Begleitforschung des Forschungsprojektes "ForReal" zu den Baden-Württembergischen Reallaboren entstanden. Dem Charakter eines Diskussionspapieres entsprechend sind die hier vorstellten Rahmungen zum Reallaboransatz als Angebot zur Diskussion, Erweiterung und Verbesserung zu verstehen

Gastrocnemius muscle herniation as a rare differential diagnosis of ankle sprain: case report and review of the literature

BACKGROUND: Muscle herniation of the leg is a rare clinical entity. Yet, knowing this condition is necessary to avoid misdiagnosis and delayed treatment. In the extremities, muscle herniation most commonly occurs as a result of an acquired fascial defect, often due to trauma. Different treatment options for symptomatic extremity muscle herniation in the extremities, including conservative treatment, fasciotomy and mesh repair have been described. CASE PRESENTATION: We present the case of a patient who presented with prolonged symptoms after an ankle sprain. The clinical picture showed a fascial insufficiency with muscle bulging under tension. Ultrasound and MRI imaging confirmed the diagnosis of muscle hernia of the medial gastrocnemius on the right leg. Conservative treatment did not lead to success. Therefore, the fascial defect was treated surgically by repairing the muscle herniation using a synthetic vicryl propylene patch. CONCLUSIONS: Muscle hernias should be taken into consideration as a rare differential diagnosis whenever patients present with persisting pain or soft tissue swelling after ankle sprain. Diagnosis is mainly based on clinical aspect and physical examination, but can be confirmed by radiologic imaging techniques, including (dynamic) ultrasound and MRI. If conservative treatment fails, we recommend the closure with mesh patches for large fascial defects

Microdialysis of the rectus abdominis muscle for early detection of impending abdominal compartment syndrome

Objective: To investigate whether microdialysis is capable of assessing metabolic derangements during intra-abdominal hypertension (IAH), and whether monitoring of the rectus abdominis muscle (RAM) by microdialysis represents areliable approach in the early detection of organ dysfunctions in abdominal compartment syndrome (ACS). Design: Prospective, randomized, controlled animal study. Setting: University animal research facility. Subjects: Fifteen isoflurane-anesthetized and mechanically ventilated Sprague-Dawley rats. Interventions: IAH of 20 mmHg was induced for 3 h and followed by decompression and reperfusion for another 3-h period (n = 10). Five sham-operated animals served as controls. Microdialysis was performed in the anterior gastric wall, liver, kidney, and RAM. The anterior cervical muscles served as distant reference. Glucose, lactate, pyruvate, and glycerol was analyzed throughout the 6-h experiment. Measurements and main results: Prolonged IAH induced significant cardiopulmonary dysfunction and persistent abdominal organ injury. Microdialysis revealed asignificant increase of lactate/pyruvate and glycerol in kidney, intestine and liver, indicating ischemia, energy failure, and cell membrane damage. In addition, at 3 h IAH glucose was significantly decreased in all organs studied. The distant reference did not show any alteration of lactate/pyruvate, glycerol, and glucose over the entire 6-h observation period. In contrast to the other organs, microdialysis of the RAM showed an early and more pronounced increase of lactate, lactate/pyruvate and glycerol already at 1 h IAH. It is noteworthy that lactate, glycerol, and glucose did not completely recover upon decompression of IAH. Conclusions: Our data suggest that continuous microdialysis in the RAM may represent apromising tool for early detecting IAH-induced metabolic derangement