Modified Candy-Package technique vs Cerclage technique for refixation of the lesser trochanteric fragment in pertrochanteric femoral fractures. A biomechanical comparison of 10 specimens.

OBJECTIVES: Separation of the lesser trochanteric fragment in pertrochanteric 3-part fractures leads to a significant weakening of the medial cortical wall. Because of the attachment of the Iliopsoas muscle to this structure, the lesser trochanteric fragment tends to cranial dislocation along this muscle's action direction. Refixation of these fractures using an intramedullary nail and an additional wiring osteosynthesis can be considered an operative standard. Based on an intramedullary osteosynthesis procedure, the question was raised whether a 2-point fixation method was favourable over a 1-point method regarding the pull-out resistance of the lesser trochanteric fragment against the Iliopsoas muscle's force. METHODS: Based on an intramedullary osteosynthesis (PFNA, DePuy/Synthes/SUI), two groups á five human femora were defined depending on the refixation technique of the lesser trochanteric fragment (1-point supertrochanteric "Cable" vs 2-point super/subtrochanteric fixation "Candy-Package" performed with a 1.25-mm steel cerclage). The specimens were tested using a novel traction setup, simulating the activity pattern of the Iliopsoas muscle. The target value was the resistance of the refixated lesser trochanteric fragment against a defined pull-out force produced by the Iliopsoas muscle. The main parameters considered were the peak traction force (Fmax) and the maximum summative work (WFmax) at construct failure. RESULTS: The Fmax and WFmax displayed a significant difference in favour of the Candy-Package (2-point super/subtrochanteric fixation) group (822 N vs. 476 N, 13.8 k Nmm vs 4.4 k Nmm, respectively; P = 0.01). CONCLUSIONS: The Candy-Package technique is a method that displays significantly more resistance than a single cerclage osteosynthesis regarding fragment loosening under the application of a simulated Iliopsoas muscle force in the course of a biomechanical proximal femoral 3-part fracture model.

Clinical and aesthetic outcome analysis of a case series of trigonocephaly patients after early fronto-orbital advancement.

The timing of operation for trigonocephaly is recommended before the age of 1 year. To evaluate the outcome of a consecutive series operated in a single centre, the current study was performed. The study cohort comprised a retrospective single-centre series of 20 patients with trigonocephaly operated before the age of 12 months. Intra- and postoperative clinical data, as well as aesthetic outcome measured by two-dimensional asymmetry index (2D AI) and correction of the curvature on lateral and pictures from above were evaluated. Furthermore, to evaluate postoperative aesthetic outcome, a new classification (Grades I-IV) was proposed. The mean age of the cohort was 7.9 months. 2D AI changed from 0.049 pre- to 0.03 postoperatively (P=0.165). The correction of the curvature in lateral pictures yielded a significant change on postoperative pictures (P=0.002) as well as on pictures from above. Using the proposed classification, 16/20 (80%) patients had a postoperative outcome of Grade I, 4/20 (20%) Grade II. In patients operated before the age of 12 months an excellent (Grade I, AI <0.03) or good aesthetic (Grade II, adequate parents' or surgeon's opinion) result could be reached in all patients.

Tricalcium phosphate-based biocomposites for mandibular bone regeneration--A histological study in sheep.

The present study investigated the suitability of three different absorbable biocomposites for the repair of critical sized bone defects created at the mandibular angle of adult sheep. Each biocomposite was composed of a three-dimensional individualized polylactide scaffold, containing a tricalcium phosphate biomaterial (chronOS). Either autologous bone marrow (chOS/BoneMarrow) or coagulation factor XIII (chOS/FactorXIII) was added to the biomaterial for osteopromotion. Venous whole blood (chOS/Blood) added to the biomaterial served as a control. A total of 18 adult sheep were used for implantation studies, subdivided into three groups of six animals each. After 12 weeks of observation, the animals were sacrificed and the mandibles were retrieved for qualitative and quantitative histologic assessment within three regions of interest (transitional zone, center, and periphery) throughout the biocomposites. Successful bone regeneration was defined by the absence of scaffold deformation and the presence of new bone formation within the biocomposites. In histomorphometry, only chOS/BoneMarrow showed elevated area fractions of newly formed bone in all regions of interest (transitional zone 50.7 ± 7.5, center 31.9 ± 9.3, periphery 23.1 ± 13.5). This led to preservation of the macroscopic scaffold structure in all specimens. Zero hurdle regression confirmed this by validating the factor biocomposite as significant (p < 0.001) for regeneration success. In our experiment, chOS/BoneMarrow was the only biocomposite passing the hurdle of regeneration in all three regions of interest. In contrast, bone formation was less pronounced and uniform in chOS/FactorXIII and chOS/blood-containing specimens. In these groups, scaffolds showed obvious to significant deformation. Overall, autologous bone marrow showed the most promising results in our experimental setting. As opposed to reports in the literature, we could not confirm the suitability of coagulation factor XIII to promote bone formation, since bone formation rates were comparable only to those of the control venous blood.

HCRP1 expression status is a significant prognostic marker in oral and oropharyngeal cancer.

OBJECTIVE: The hepatocellular carcinoma-related protein 1 (HCRP1) is a key factor in the degradation of the epidermal growth factor receptor. In this study, we assessed the prognostic significance of HCRP1 expression in patients with oral and oropharyngeal squamous cell carcinoma (OOSCC). METHODS: HCRP1 expression was determined by immunohistochemistry on tissue biopsy sections of 111 patients with locally advanced OOSCC undergoing neoadjuvant chemoradiotherapy followed by surgery. The Kaplan-Meier method and Cox regression models were used for survival analyses. RESULTS: Low HCRP1 expression was associated with poor recurrence-free survival (P = 0.046) and overall survival (P = 0.03). Multivariate analysis revealed that low HCRP1 expression remained an independent risk factor for relapse (HR 2.98, 95% CI 1.19-7.49, P = 0.02) and death (HR 3.04, 95% CI 1.19-7.79, P = 0.02). CONCLUSION: Low HCRP1 expression was found to be of adverse prognostic significance in patients with OOSCC who received preoperative chemoradiotherapy.

Intra-operative rewarming with Hot Dog(®) resistive heating and forced-air heating: a trial of lower-body warming.

Resistive heating is an alternative to forced-air warming which is currently the most commonly used intra-operative warming system. We therefore tested the hypothesis that rewarming rates are similar with Hot Dog(®) (Augustine Biomedical) resistive and Bair Hugger(®) (Arizant) forced-air heating systems. We evaluated 28 patients having major maxillary tumour surgery. During the establishment of invasive monitoring, patients became hypothermic, dropping their core temperature to about 35 °C. They were then randomly assigned to rewarming with lower-body resistive (n = 14) or forced-air (n = 14) heating, with each system set to 'high'. Our primary outcome was the rewarming rate during active heating over a core temperature range from 35 to 37 °C. Morphometric characteristics were comparable in both groups. Temperature increased at twice the rate in patients assigned to forced-air warming, with an estimated mean (SE) slope of 0.49 (0.03) °C.h(-1) vs 0.24 (0.02) °C.h(-1) (p < 0.001). Resistive heating warmed at half the rate of forced air.

Bone regeneration using a naturally grown HA/TCP carrier loaded with rh BMP-2 is independent of barrier-membrane effects.

The present study investigated whether bone regeneration and biomaterial replacement would be improved by loading of biogenous biphasic biomaterial scaffolds (HA/TCP ratio 30/70) with rhBMP-2, and whether the placement of three barrier membranes differing in structure and porosity (prototyped SLA Ti specimens, GORE RESOLUT Adapt specimens, and titanized TiMESH light specimens) would have a synergistic effect. A rabbit calvarial model was used for the implantation studies. Histological specimens were obtained after 12 weeks and evaluated quantitatively for differences between the various material combinations. Loading of the biomaterials with rhBMP-2 significantly enhanced the amount of regenerated bone and caused a pronounced biomaterial replacement. While BMP-induced bone had formed uniformly over the surgical defects, bone regeneration in the absence of BMP depends on bone promotion from the margins of the defects toward the center. No positive effect on bone regeneration was seen for any of the placed barrier membranes. While the present study had shown that rhBMP-2 loading significantly increases bone regeneration using the investigated biomaterial, barrier-membrane placement may be useful in predetermining the final shape of the regenerative site but provides no additional beneficial impact on the amount and quality of the bone regeneration induced by rhBMP-2.

Guided bone regeneration with titanium membranes: a clinical study.

Guided bone regeneration using barrier membranes is useful in bone augmentation. Because the commonly used polytetrafluoroethylene (PTFE, Gore-Tex (R), WL Gore, Flagstaff, AZ, USA) membranes or resorbable membranes tend to collapse, more stable membranes are desirable. A titanium membrane (FRIOS(R) BoneShield, Friatec, Mannheim, Germany) was evaluated in a clinical study of 52 patients. Most of them had particulate bone grafts or phycogene hydroxyapatite (Algipore(R), Friatec, Mannheim, Germany) or both stabilized with titanium membranes. In 78 procedures, 23 membranes (29%) became exposed, but only seven of these (9%) led to failure of the graft with a considerable loss of augmented material. The time interval between operation and possibly exposure was responsible for the result. Early exposures (within a few weeks) led to poor formation of new bone within the grafts, whereas if exposure was later, results were as good as in procedures in which the membranes did not become exposed.

Computer-aided surgery in distraction osteogenesis of the maxilla and mandible.

When using unidirectional intraoral distraction devices, it is desirable to be able to determine the final position of the bone fragment after the distraction procedure. However, additional constraining forces from adjacent tissues render the prediction of the distraction direction difficult. We have utilised computer-aided surgery in three patients for intraoperative control of the distraction direction. In one cleft palate patient, suffering from maxillary hypoplasia and anterior open bite, a modified Le Fort I osteotomy and maxillary distraction was performed. Despite a ventrocaudal position of the distraction device, intraoperative computer visualisation showed an unfavourable caudal vector of distraction without any anterior movement. The final result confirmed the direction indicated by the computer. Maxillary advancement remained insufficient. In two patients suffering from mandibular hypoplasia, intraoperative assessment revealed a favourable direction of distraction. The distraction procedure led to a satisfactory result in both cases. Computer-aided surgery is helpful in assessing the vector of distraction intraoperatively, making the result of the distraction procedure more predictable and allowing instant correction by adequate reapplication of the device.

Positioning of dental implants using computer-aided navigation and an optical tracking system: case report and presentation of a new method.

A navigation system for computer-aided surgery (Virtual Patient System, VPS) has been described in previous studies for different indications in oral and maxillofacial surgery. The aim of the system is the intraoperative transfer of preoperative planning on radiographs or CT scans on the patient, in real-time, and independent of the position of the patient's head. Until now an electromagnetic tracking system has been used for intra-operative position measurement. For placement of dental implants, the electromagnetic tracking system is not suitable since the motor of the implant drill leads to a considerable distortion of the magnetic field, thus direct visualization of drilling the implant socket was not possible. To overcome this problem, an optical tracking system which is not disturbed by conductive materials was integrated in the VPS system. The first patient operated on with this system had a posttraumatic loss of the upper incisors; three implants have been placed according to the prosthetic axis previously planned on radiographs and CT scans. The experience gained in this intervention led to the conclusion that computer-aided surgery provides a valuable tool in implant dentistry.

Histomorphologic findings on human bone samples six months after bone augmentation of the maxillary sinus with Algipore.

Sinus grafting, a popular and standard treatment for maxillary atrophy, uses a variety of grafting materials. In this study, specimens obtained 6 months after sinus grafting with Algipore were evaluated under light microscopy and showed osseoformation, xenograft degradation, and bone ingrowth into particles. Osteoblastic cells were embedded in the intracorpuscular bone matrix, which indicated that xenograft particles are an osseoconductive scaffold and stimulate matrix deposition. Acute inflammatory responses after insertion of Algipore did not occur. Particles were degraded during physiologic bone remodeling, and newly formed bone gradually replaced resorbed biomaterial.

Remote stereotactic visualization for image-guided surgery: technical innovation.

Additional data from imaging sources using computer navigation assistance enables virtual visualization of anatomical structures in three dimensions for stereotactic navigation during an operation. Recent developments in communication technology enable the broadcasting not only of video data, but also of stereotactic navigation data via the network. By telepresence/teleconsulting, the composite images and overlapping graphics (instrument, target structure, landmark, contour) can be seen in connected clinics, with the possibility of interactive graphic assistance. In cranio-maxillofacial surgery, the first surgical teleconsultation in real time via telecommunication of stereotactic data was performed in August 1996. A patient suffering from a post-traumatic deformity following multiple comminuted midface fractures was re-osteotomized with the aid of image-guided surgery using teleconsultation: the intraoperative position achieved could be discussed with different surgeons with regard to symmetry, hard/soft tissue relationships and occlusal details, with the possibility of on-screen planning interaction and real time evaluation of the results, over a distance of 500 km.

The correlation between tissue differentiation and production of mammary tumor virus (MTV) in transplanted murine mammary tumors. Electron microscopic observations.

The spontaneous mammary tumors of the NMRI mouse are well developed microcystic adenocarcinomas. Serial isologous transplantation of the tumors results in nearly complete dedifferentiation to a solid tumor, in which only electron-microscopically rudimentary acinus-like microlumina can be observed. The adenocarcinomas produce A and B particles in abundance, with the A particles appearing intracellularly in the adluminal cytoplasmic regions of the epithelial cells in association with typical cellular structures and the B particles being restricted to closed extracellular compartments such as vacuoles or acini alone. The loss of alveolar organization in the solid tumors is followed by an almost complete reduction in mature B particles, while A particles are still regularly observed and appear to be less reduced in number. This suggests that the production of extracellular B particles is dependent upon the secretory activity of the tumor cells and that in nonsecreting cells it is predominantly a late step in virus release that is inhibited, not the synthesis of intracellular precursors.

Tissue connections in a transplantable virus-producing sebaceous adenoma of the mouse. II. A freeze-fracture study in conjunction with filipin.

The distribution, size, and configuration of intercellular junctions in the sebaceous tumor of mice were examined using the freeze-fracture technique. Three types of junctions were observed: desmosomes, gap, and tight junctions. Tight junctions in general consisted of short linear unbranched fibrils, and macular or complex tight junctional patterns were present only occasionally. Gap junctions ranged from small sports of 0.9 x 10(-3) micrometer2 to areas of approximately 0.46 micrometers2. Desmosomes were the most frequent junctional specializations, and it is concluded that they are at least partially responsible for this tumor not being metastatic. Filipin in conjunction with freeze-fracture showed filipin-sterol complexes on the plasma membrane, the nuclear envelope, and the membranes of the endoplasmic reticulum and mitochondria. The intercellular junctions were devoid of these complexes indicating that these regions are low in cholesterol.

Structure and function of the junctional complement of spontaneous and transplanted murine mammary carcinomas.

In this study the morphology of intercellular junctions in a murine mammary adenocarcinoma and in a solid carcinoma which resulted from continuous transplantations of this spontaneous tumor are described employing the techniques of ultrathin-sectioning after conventional fixation and tannic acid fixation and freeze-fracturing. The acini of the original adenocarcinoma are separated from the intercellular spaces by tight junctions which form a narrow belt-like zonula around the adluminal parts of all epithelial cells. The apical-to-basal width of the tight junctions varies from 0.4 to 0.8 micrometer. Desmosomes and gap junctions are located close to the zonulae occludentes. The size of gap junctions ranges from small spots 0.2 micrometer in diameter to large areas approximately 1.5 micrometer in diameter. In the solid carcinoma these cellular junctions appear without acinar organization randomly between the cells. In addition, special contact zones can be observed. The contact zones seem to be the precursors of a formation plaque for gap or tight junction formation. The sizes of the gap junctions show a wide range of variation, from as small as 5 particles to as large as 0.5 micrometer in diameter. Tight junctions do not form continuous belt-like zonulae indicating that they have lost their significance as a permeability barrier. They are interpreted as mechanical links. In addition to isolated gap junctions and tight junctions there exist gap junctions adjacent to tight junction fibrils suggesting a probable biogenetic relationship of these two structures.

Tissue connections in a transplantable virus-producing sebaceous adenoma of the mouse.

In this study a transplantable sebaceous adenoma is presented, which maintained its histological structure with similarities to normal sebaceous glands over a long series of transplantations. From the periphery toward the center a basal lamina, an outer layer of undifferenciated stem cells, loosely connected secreting tissue, a tightly packed zone of close cell attachment, and finally a central sebaceous zone can be distinguished. Special reference is made to the belt-like region around the zone of cell lysis and sebum accumulation, which forms a barrier to the surrounding tissue by means of numerous cell adhesions in the form of desmosomes. Relatively few virus particles of the retrovirus group, particularly type A particles, were found in any of the examined tumors.

Electron-microscopic morphology of virus replication in cells of the murine Borstel-leukemia X 429.

Intraperitoneal injections of cell-free filtrates of Borstel-leukemia X 429 (immature-cell myeloid leukemia induced by 200 rad whole-body X-irradiation) were given to 330 1-week-old NMRI mice of both sexes. Leukemia developed in 21% after injection of cell-free filtrates from leukemic spleens and in 20% after injection of cell-free filtrates from leukemic lymph nodes. The mean time lapse from injection to the appearance of the leukemia was 12.8 months. The virus replication in the newly formed leukemic cells, was studied by electron microscopy. Special attention was given to the relation between A-particles and mature type-C viruses. The leukemia cells contain intracytoplasmic and intracisternal A-particles consisting of two concentric spherical shells with an external diameter of 70 nm. A-particles present mainly as closed "virus fields" in the vicinity of the cell nucleus, frequently in the Golgi area. The intracisternal A-particles appear inside the lumen of expanded vesicles of the cytoplasma. Typ-C viruses develop on the cytoplasmic membrane and/or on the outer cell membrane by condensation of crescent-shaped electron-dense zones. All layers of the later mature virus are recognisable in these early morphological stages. After the virus has been detached from the cell it collapses, and the outer membrane appears wrinkled. No spatial correlation between the storage sites of the A-particles and the sites of formation of mature type-C viruses are demonstrable.