Correction to: A simple approach for the preoperative assessment of sacral morphology for percutaneous SI screw fixation.

In the original article, co-author's given name has been published incorrectly. The correct given name should be Vinzent Kevin.

A simple approach for the preoperative assessment of sacral morphology for percutaneous SI screw fixation.

BACKGROUND: Percutaneous sacroiliac screw fixation under fluoroscopic control is an effective method for posterior pelvic ring stabilization. However, sacral dysmorphism has a high risk of L5 nerve injury. This study describes a simple method for the preoperative assessment of the sacral morphology using CT scans with widely available tools. MATERIALS AND METHODS: CT scans of 1000 patients were analyzed. True inlet, outlet, and lateral views of the sacrum were obtained using a two-dimensional reconstruction tool to align the sacrum in a reproducible manner. Corridor morphology in the inlet view was measured to calculate different morphological types: (1) Ascending type, (2) Horizontal type, and (3) Descending type. In a second step, the corridor was analyzed for the presence of an anterior indentation of the sacrum between the SI joint and the midsagittal plane with proximity to the nerve root L5, which, therefore, may be harmed during screw misplacement. RESULTS: A notch was found in the majority of cases with relative frequencies ranging from 69 % (upper quartile of S1) to 95 % (upper quartile of S2). Descending types were, by far, the most frequent corridor type with one exception: In the upper quartile of S1, the ascending type was the most frequent corridor (71 %). Horizontal types were less frequent with a relative incidence between 2 and 14 %. DISCUSSION: This study should increase the awareness for sacral dysmorphism, emphasize the importance of a preoperative assessment of the osseous corridor, and provide a simple method for the preoperative assessment with widely available tools.

Treatment of large posttraumatic tibial bone defects using the Ilizarov method: a subjective outcome assessment.

BACKGROUND: The treatment of large posttraumatic tibial bone defects using the Ilizarov method was shown to be successful in several studies. These studies, however, typically focus on the radiological and functional outcome using objective parameters only. The aim of the present study was therefore to assess the objective and subjective outcome of a consecutive series of patients with large posttraumatic tibial bone defects using the Ilizarov method. Additionally, it was our goal to assess the physical and mental stress for the patients and their relatives during the long treatment period and the general health status at final follow-up. METHODS: A consecutive series of 15 patients with posttraumatic tibial bone defects of >30 mm after sustaining open tibial fractures and failure of internal fixation was included. The objective outcome was assessed at final follow-up using Paley's criteria. For the assessment of the subjective outcome, all patients were asked to evaluate their satisfaction with the function of the lower leg, the cosmetic appearance and overall outcome as well. The physical and mental stress of the treatment for the patients and the nearest relative of patients were assessed at the time of frame removal using a custom-made questionnaire. The SF-36 was used to evaluate the general health status at final follow-up. RESULTS: Solid bone union with stable soft tissue coverage and eradication of infection was achieved in all patients despite a high complication rate. The functional outcome at final follow-up was excellent or good in all patients. The patients' satisfaction with the overall outcome and the function of the lower extremity was high as well. The fear of amputation and complications was the major subjective burden for both the patients and their relatives. The long external fixation time is another relevant issue. CONCLUSION: The Ilizarov method is a safe option for the treatment of large posttraumatic tibial bone defects after failure of internal fixation despite the high complication rate. It is essential to comment this to the patients and their relatives prior to the application of the frame increase their compliance with the long and emotionally draining treatment. The Ilizarov method is worth the effort only in patients, who will presumably comply with this treatment option and all of its drawbacks.

Preoperative assessment of the cancellous bone mineral density of the proximal humerus using CT data.

BACKGROUND: Osteoporotic fractures of the proximal humerus show an increasing incidence. Osteoporosis not only influences the fracture risk after low-energy trauma, but also affects the mechanical stability of internal fixation. Preoperative assessment of the local bone quality may be useful in the surgical treatment of patients sustaining these injuries. The aim of the present study was to present a method for the preoperative assessment of the local cancellous bone mineral density (BMD) of the proximal humerus using CT data. METHODS: In the first part of the study, CT scans of 30 patients with unilateral fractures of the proximal humerus after low-energy trauma were used. The local BMD was assessed on the contralateral uninjured side. All 30 patients additionally underwent dual-emission X-ray absorptiometry (DXA) of the lumbar spine, proximal femur, and forearm of the side of the uninjured proximal humerus within 6 weeks after trauma. Three independent trauma surgeons performed measurements on the uninjured proximal humerus twice with a time interval of 4 weeks in order to assess the inter- and intraobserver reliability of the method. In the second part of the study, the local BMD of 507 patients with either proximal humerus fractures or chronic shoulder instability was assessed by a single trauma surgeon. In both parts, the average HU values in standardized ROIs of the humeral head were automatically calculated after correcting for HU values below the water equivalent. A linear calibration equation was computed for the calculation from HU to BMD using a calibration device (EFP). RESULTS: The intra- and interobserver reliability was high (ICC > 0.95). Correlation coefficients between the local BMD of the proximal humerus and other anatomical sites were between 0.35 (lumbar spine) and 0.64 (forearm). We found a high correlation between the local BMD and age. The BMD in the fracture group was significantly lower than in the instability group. These patients were significantly older and more likely to be female. CONCLUSION: Our method may provide a preoperative tool for the assessment of the local bone quality of the proximal humerus using CT data. Therapeutic adjustments such as augmentation or primary arthroplasty may be considered in patients with very low local BMD.

A pelvic fracture model for the assessment of treatment options in a laboratory environment.

BACKGROUND: Optimal prehospital and clinical management of patients with severe pelvic trauma is controversial. Prospective evaluations of different treatment strategies have not been performed and treatment is currently not evidence-based. The purpose of the present study was to develop a porcine model of reproducible severe pelvic trauma for subsequent laboratory trials. METHODS: The study was performed on 13 juvenile porcine cadavers. Pelvic fractures were created by applying a pure anterior-posterior compression load to the pelvic ring using a servohydraulic material testing machine. Fracture patterns were classified according to the Young-Burgess classification and the Tile classification using postfracture CT scans including 3D-reconstructions. RESULTS: Disruptions of the posterior pelvic ring segment were unilateral in 12 cases and bilateral in one case transforaminal vertical sacrum fractures. Injuries of the anterior ring segment were obturator ring fractures bilateral, ipsilateral or contralateral to the injury of the posterior ring segment. According to the Tile classification this resulted in 12 type C1 and 1 type C3 fractures. In the Young classification all injuries were classified as type APC III. In six cases transverse process fractures were found ipsilateral to the posterior ring disruption. Initial force drops indicating bony or ligamentous injuries occurred at mean forces of 4030 +/- 269N (range, 3617-4374N). CONCLUSION: The present model was able to create reproducible unstable pelvic fractures and can be used for controlled laboratory trials to study the management of patients with pelvic fractures.