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Objective Preoperative planning of the starting point and safe trajectory for iliosacral screw (SI screw) fixation using CT scans for safe and accurate fluoroscopically controlled percutaneous SI screw placement. Indications Transalar and transforaminal sacral fractures. SI joint disruptions and fracture-dislocations. Non- or minimally displaced spinopelvic dissociation injuries. Contraindications Transiliac instabilities. Sacral fractures with neurological impairment requiring decompression. Relevant residual displacement after closed reduction attempts. Insufficient fluoroscopic visualization of the anatomical landmarks of the upper sacrum. Surgical technique Preoperative planning of the starting point and the safe screw trajectory using CT scans and two-dimensional multiplanar reformation tools. Fluoroscopically guided identification of the starting point using the lateral view according to preoperative planning. Advancing the guidewire under fluoroscopic control using inlet and outlet views according to the planned trajectory. Predrilling and placement of 6.5 mm cannulated screws. Postoperative management Weightbearing as tolerated using crutches. Immediate CT scan in case of postoperative neurological impairment. Generally no screw removal. Results Fifty-nine screws were placed in 34 patients using the described technique. There were 2 cases of screw malpositioning (anatomical landmarks inadequately identified and fluoroscopically controlled SI screw fixation should thus not have been performed at all; in a case with sacral dysmorphism, preoperative planning suggested a posterior and/or caudal S1 starting point, respectively, but intraoperatively, selection of a different starting point and screw trajectory resulted in screw malpositioning with iatrogenic L5 nerve palsy).

Introduction Nonunion is a common complication after intramedullary nailing of subtrochanteric femoral fractures. A more detailed knowledge, particularly of avoidable risk factors for subtrochanteric fracture nonunion, is thus desired to develop strategies for reducing nonunion rates. The aim of the present study therefore was to analyse a wide range of parameters as potential risk factors for nonunion after intramedullary nailing of subtrochanteric fractures. Materials and methods Seventy-four patients who sustained a subtrochanteric fracture and were treated by femoral intramedullary nailing at a single level 1 trauma centre within a 6-year period were included in this study. A total of 15 patient-related, fracture-related, surgery-related, mechanical and biological parameters were analysed as potential risk factors for nonunion. Furthermore, the accuracy of each of these parameters to predict nonunion was calculated. Results Nonunion occurred in 17 of 74 patients (23.0%). Of the 15 potential risk factors analysed, only 3 were found to have a significant effect on the nonunion rate (p 0.70. Furthermore, the nonunion rate significantly increased with the number of risk factors (no risk factor: 2.9%, one risk factor: 23.8%, two risk factors: 52.9%, and three risk factors: 100% [Chi-square test, p = 0.001)]. Conclusions Our study indicates that intraoperative correction of varus malalignment and restoration of the medial cortical support are the most critical factors to prevent nonunion after intramedullary nailing of subtrochanteric femoral fractures. In addition, autodynamisation of the nail within the first 3 months post-surgery is a strong predictor for failure and should result in revision surgery.

Introduction In combined posterior–anterior stabilization of thoracolumbar burst fractures, the expandable vertebral body replacement device (VBRD) is typically placed bisegmentally for anterior column reconstruction (ACR). The aim of this study, however, was to assess feasibility, outcome and potential pitfalls of monosegmental ACR using a VBRD. In addition, clinical and radiological outcome of monosegmental ACR was related to that of bisegmental ACR using the same thoracoscopic technique. Methods Thirty-seven consecutive neurologically intact patients with burst fractures of the thoracolumbar junction (T11–L2) treated by combined posterior–anterior stabilization were included. Monosegmental ACR was performed in 18 and bisegmental ACR in 19 patients. Fracture type and extent of vertebral body comminution were determined on preoperative CT scans. Monosegmental and bisegmental kyphosis angles were analyzed preoperatively, postoperatively and at final radiological follow-up. Clinical outcome was assessed after a minimum of 2 years (74 ± 45 months; range 24–154; follow-up rate 89.2%) using VAS Spine Score, RMDQ, ODI and WHOQOL-BREF. Results Monosegmental ACR resulted in a mean monosegmental and bisegmental surgical correction of − 15.6 ± 7.7° and − 14.7 ± 8.1°, respectively. Postoperative monosegmental and bisegmental loss of correction averaged 2.7 ± 2.7° and 5.2 ± 3.7°, respectively. Two surgical pitfalls of monosegmental ACR were identified: VBRD positioning (1) onto the weak cancellous bone (too far cranially to the inferior endplate of the fractured vertebra) and (2) onto a significantly compromised inferior endplate with at least two (even subtle) fracture lines. Ignoring these pitfalls resulted in VBRD subsidence in five cases. When relating the clinical and radiological outcome of monosegmental ACR to that of bisegmental ACR, no significant differences were found, except for frequency of VBRD subsidence (5 vs. 0, P = 0.02) and bisegmental loss of correction (5.2 ± 3.7° vs. 2.6 ± 2.5°, P = 0.022). After exclusion of cases with VBRD subsidence, the latter did not reach significance anymore (4.9 ± 4.0° vs. 2.6 ± 2.5°, P = 0.084). Conclusions This study indicates that monosegmental ACR using a VBRD is feasible in thoracolumbar burst fractures if the inferior endplate is intact (incomplete burst fractures) or features only a single simple split fracture line (burst-split fractures). If the two identified pitfalls are avoided, monosegmental ACR may be a viable alternative to bisegmental ACR in selected thoracolumbar burst fractures to spare a motion segment and to reduce the distance for bony fusion.

Pedicle screw loosening is a common and significant complication after posterior spinal instrumentation, particularly in osteoporosis. Radiolucent carbon fiber-reinforced polyetheretherketone (CF/PEEK) pedicle screws have been developed recently to overcome drawbacks of conventional metallic screws, such as metal-induced imaging artifacts and interference with postoperative radiotherapy. Beyond radiolucency, CF/PEEK may also be advantageous over standard titanium in terms of pedicle screw loosening due to its unique material properties. However, screw anchorage and loosening of CF/PEEK pedicle screws have not been evaluated yet. The aim of this biomechanical study therefore was to evaluate whether the use of this alternative nonmetallic pedicle screw material affects screw loosening. The hypotheses tested were that (1) nonmetallic CF/PEEK pedicle screws resist an equal or higher number of load cycles until loosening than standard titanium screws and that (2) PMMA cement augmentation further increases the number of load cycles until loosening of CF/PEEK screws. In the first part of the study, left and right pedicles of ten cadaveric lumbar vertebrae (BMD 70.8 mg/cm3 ± 14.5) were randomly instrumented with either CF/PEEK or standard titanium pedicle screws. In the second part, left and right pedicles of ten vertebrae (BMD 56.3 mg/cm3 ± 15.8) were randomly instrumented with either PMMA-augmented or nonaugmented CF/PEEK pedicle screws. Each pedicle screw was subjected to cyclic cranio-caudal loading (initial load ranging from − 50 N to + 50 N) with stepwise increasing compressive loads (5 N every 100 cycles) until loosening or a maximum of 10,000 cycles. Angular screw motion (“screw toggling”) within the vertebra was measured with a 3D motion analysis system every 100 cycles and by stress fluoroscopy every 500 cycles. The nonmetallic CF/PEEK pedicle screws resisted a similar number of load cycles until loosening as the contralateral standard titanium screws (3701 ± 1228 vs. 3751 ± 1614 load cycles, p = 0.89). PMMA cement augmentation of CF/PEEK pedicle screws furthermore significantly increased the mean number of load cycles until loosening by 1.63-fold (5100 ± 1933 in augmented vs. 3130 ± 2132 in nonaugmented CF/PEEK screws, p = 0.015). In addition, angular screw motion assessed by stress fluoroscopy was significantly smaller in augmented than in nonaugmented CF/PEEK screws before as well as after failure. Using nonmetallic CF/PEEK instead of standard titanium as pedicle screw material did not affect screw loosening in the chosen test setup, whereas cement augmentation enhanced screw anchorage of CF/PEEK screws. While comparable to titanium screws in terms of screw loosening, radiolucent CF/PEEK pedicle screws offer the significant advantage of not interfering with postoperative imaging and radiotherapy. These slides can be retrieved under Electronic Supplementary Material.

Introduction Straight antegrade humeral nailing (SAHN) has become a standard technique for the surgical fixation of proximal humeral fractures, which predominantly affect elderly females. The nail’s proximal anchoring point has been demonstrated to be critical to ensure reliable fixation in osteoporotic bone and to prevent iatrogenic damage to the superior rotator cuff bony insertion. Anatomical variations of the proximal humerus, however, may preclude satisfactory anchoring of the nail’s proximal end and may bare the risk of rotator cuff violation, even though the nail is inserted as recommended. The aim of this study was to evaluate the anatomical suitability of proximal humeri of geriatric females aged 75 years and older for SAHN. Specifically, we sought to assess the proportion of humeri not anatomically amenable to SAHN for proximal humeral fracture. Materials and Methods A total of 303 proximal humeri of 241 females aged 75 years and older (mean age 84.5 ± 5.0 years; range 75–102 years) were analyzed for this study. Multiplanar two-dimensional reformations (true ap, true lateral, and axial) were reconstructed from shoulder computed tomography (CT) data sets. The straight antegrade nail’s ideal entry point, “critical point” (CP), and critical distance (CD; distance between ideal entry point and CP) were determined. The rate of proximal humeri not anatomically suitable for SAHN (critical type) was assessed regarding proximal reaming diameters of currently available straight antegrade humeral nails. Results Overall, 35.6% (108/303) of all proximal humeri were found to be “critical types” (CD

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.

Tumor grade is a traditional prognostic parameter in colorectal cancer. Remarkably, however, there is still no generally accepted consensus how to perform tumor grading. In this study, we systematically compared the prognostic value of traditional grading based upon histological features, that is, gland formation alone with grading based upon both histological and cytological features, such as nuclear pleomorphism and anaplasia (“alternative grade”). Three hundred eighty-one tumors of randomly selected patients were retrospectively reviewed. Traditional and alternative tumor grades were related to various clinicopathological features and to progression-free and cancer-specific survival applying both univariate and multivariate testing. Traditional and alternative tumor grades were significantly associated with T and N classification, tumor size, lymphovascular invasion, as well as both progression-free and cancer-specific survival. In Cox’s proportional hazards regression models, the alternative grade was superior to the traditional tumor grade and was significantly associated with progression-free survival (hazard ratio 1.57, 95 % confidence interval 1.04–2.35; p = 0.031), independent of patients’ age and gender, T and N classification, and lymphovascular invasion. Likewise, patients with tumors with high alternative grade were more likely to die of disease (hazard ratio 1.30, 95 % confidence interval 0.85–2.00), but this difference was not statistically significant (p = 0.22). Tumor grade based upon both histological and cytological features was superior to grade based upon histological features alone and proved to be an independent prognostic parameter. Thus, tumor grade based upon both histological and cytological features may help to improve prognostic stratification and may thereby affect clinical decision-making and patient management.

Background: Tumour budding is an adverse prognostic indicator in colorectal cancer (CRC). Marked overall peritumoural inflammation has been associated with favourable outcome and may lead to the presence of isolated cancer cells due to destruction of invading cancer cell islets. Methods: We assessed the prognostic significance of tumour budding and peritumoural inflammation in a cohort of 381 patients with CRC applying univariate and multivariate analyses. Results: Patients with high-grade budding and marked inflammation had a significantly better outcome compared with patients with high-grade budding and only mild inflammation. Outcome in these cases, however, was still worse compared with cases with low-grade budding, in which the extent of peritumoural inflammation had no further prognostic effect. Conclusions: Tumour budding proved to be a powerful prognostic variable in patients with CRC. Scattering of invading cancer cell islets by marked overall peritumoural inflammation seems to have a minor role.

Behandlung groser dia- und metaphysarer Knochendefekte (> 3 cm) in zwei operativen Eingriffen mit einem zeitlichen Abstand von 4–8 Wochen. Dia- und metaphysare Knochendefekte vorwiegend am Unter- und Oberschenkel. Knochendefekte mit Gelenkbeteiligung, persistierender Knocheninfekt oder Osteomyelitis, insuffiziente Weichteildeckung im Bereich des Knochendefekts, Osteoporose. Ersteingriff: Ausgiebiges Knochendebridement und Weichteildeckung, Einbringen eines Zementspacers in den Knochendefekt zur Induktion einer synovialen Fremdkorpermembran, interne oder externe Stabilisierung. Zweiteingriff: Entfernen des Zementspacers und Fullung des von der induzierten Membran umgebenen Knochendefekts mit autologer Spongiosa, ggf. Verfahrenswechsel auf eine interne Fixation. Schmerzabhangige Teil- bis Vollbelastung nach dem Ersteingriff. Abrollende Mobilisation nach dem Zweiteingriff bis zum Auftreten von radiologischen Zeichen eines Remodellings des Regenerats. In der Regel Belassen des Implantats. Insgesamt wurden 6 Patienten (4 Manner, 2 Frauen) im Alter von 15–66 Jahren mit Knochendefekten von durchschnittlich 7 cm (Spanne 4–10 cm) mit der Masquelet-Technik behandelt. Es handelte sich um 2 femorale aseptische Pseudarthrosen und 4 tibiale Pseudarthrosen (je 2 septische und aseptische Pseudarthrosen), dabei in einem Fall um eine periprothetische Pseudarthrose an der Tibia bei schaftgefuhrter Knieprothese. Die Stabilisierung nach Debridement erfolgte an der Tibia in allen Fallen zunachst mit einem Ringfixateur, am Femur einmal mit einem Marknagel und einmal mit einer winkelstabilen Platte. Der Zweiteingriff wurde zwischen 6 und 9 Wochen nach dem Ersteingriff durchgefuhrt. Dabei wurde in 3 von 4 Fallen an der Tibia ein Verfahrenswechsel auf eine interne Fixation durchgefuhrt. Die Spongiosa wurde entweder vom Beckenkamm oder in RIA-Technik („Reamer-Irrigator-Aspirator“) entnommen. Bei der Patientin mit dem periprothetischen Knochendefekt kam es nach 5 Monaten zu einem Plattenbruch und konsekutiver Unterschenkelamputation. In einem Fall wurde aufgrund einer Pseudarthrose an der Andockstelle eine lokale Spongiosaplastik durchgefuhrt. Alle Patienten waren nach 6 Monaten schmerzfrei und vollbelastend mobil. Der Ilizarov-Fixateur konnte bei einem 15-jahrigen Patienten 5 Monate nach dem Zweiteingriff entfernt werden. Die restlichen Implantate wurden belassen.

In colorectal cancer, the morphology of the invasive tumor margin may reflect aggressiveness of tumor growth, thus providing important prognostic information. The tumor growth pattern according to Jass and the extent of tumor budding were analyzed in patients with American Joint Committee on Cancer/Union for International Cancer Control (AJCC/UICC) stage II disease.Tumors of 120 randomly selected patients with AJCC/UICC stage II disease were retrospectively reviewed for tumor growth pattern (expanding vs. infiltrating) and the extent of tumor budding, with high-grade budding reflecting presence of 10 or more budding foci scattered at the invasive tumor margin. Progression-free and cancer-specific survivals were determined by the Kaplan-Meier method. For multivariable analysis, Cox's proportional hazards regression models were performed.The infiltrating growth pattern was significantly associated with histological subtype and lymphovascular invasion, while high-grade budding was significantly associated with tumor grade and lymphovascular invasion. High-grade budding, but not the infiltrating growth pattern, was significantly associated with outcome in univariable analysis. Cox's proportional hazards regression models proved tumor budding to be an independent predictor of disease progression (hazard ratio 3.91, 95 % confidence interval 1.3-11.77; P = 0.02) and cancer-related death (hazard ratio 5.90, 95 % confidence interval 1.62-21.51; P = 0.007). The combination of infiltrating growth pattern and high-grade budding did not have a stronger prognostic significance than tumor budding alone.Tumor budding independently predicted patient outcome in patients with AJCC/UICC stage II colorectal cancer and may therefore be used for accurate prognostication, patient counseling, and design of clinical trials by using integrated multimodal therapy.