Bimaxillary distraction osteogenesis--an effective approach for the transverse jaw discrepancies in adults.

Severe dental crowding in adult patients is one of the features of disparity between the size of the teeth and the jaws. It is most frequently found in cases with a transverse hypoplasia of the maxilla and the mandible. The traditional orthodontic approach is extraction of teeth or arch expansion, both of them with major esthetic disadvantages for the patients. The surgically assisted maxillary expansion (SARME) and the mandibular midsymphyseal distraction osteogenesis procedures open new horizons for the orthodontists and maxillofacial surgeons in the effort to solve the esthetic demands of the patients with dental crowding and severe transversal discrepancy. The amount of surgical expansion is of higher magnitude and stability then the one achieved in orthodontic cases. The case presented here highlights the importance of the surgical procedure followed by the orthodontic therapy due to the enhancement in occlusion, dental alignment and facial morphology.

Intraoperative blood loss in bimaxillary orthognathic surgery with multisegmental Le Fort I osteotomies and additional procedures.

Autologous blood donation is not currently recommended by most authors for routine bimaxillary osteotomies. There are few data about bimaxillary procedures with multisegmental maxillary osteotomies. Our aim was to investigate the effect of additional osteotomies and iliac crest grafts on operative blood loss. A total of 225 consecutive patients having bimaxillary multisegmental osteotomies during a three-year period (January 2006-January 2009) were examined to see if their haemoglobin concentration and packed cell volume were reduced. The influence of iliac crest grafts, additional osteotomies (genioplasty, malar osteotomy, iliac crest graft, anterior mandibular segmental osteotomy), operating time, age, and sex were assessed. Neither age nor sex influenced blood loss, whereas operating time correlated significantly with reductions in haemoglobin concentration and packed cell volume. Blood loss was significantly higher in the group who had additional procedures (p 0.001 for haemoglobin concentration and packed cell volume) than in the group who had no additional procedures, whereas there were no significant differences among the three subgroups who had additional procedures (additional osteotomies, iliac crest grafts, or both procedures). Four patients who had additional procedures required transfusion, whereas no blood was given in the group who had no additional procedures. Because the transfusion rate was so low, we could make no general recommendation for preoperative blood donation in such cases.

Accuracy of maxillary positioning in bimaxillary surgery.

The aim of the study was to investigate the accuracy of a modified pin system for the vertical control of maxillary repositioning in bimaxillary osteotomies. The preoperative cephalograms of 239 consecutive patients who were to have bimaxillary osteotomies were superimposed on the postoperative films. Planned and observed vertical and horizontal movements of the upper incisor were analysed statistically. The mean deviations of -0.07 mm (95% confidence intervals (CIs) -0.17 to 0.04 mm) for the vertical movement and 0.12 mm (95% CI -0.06 to 0.30 mm) for the horizontal movement did not differ significantly from zero. Comparison of the two variances between intrusion and extrusion of the maxilla did not differ significantly either (p=0.51). These results suggest that the modified pin system for vertical control combined with interocclusal splints provides accurate vertical positioning of the anterior maxilla in orthognathic surgery.

Changes in acoustic airway profiles and nasal airway resistance after Le Fort I osteotomy and functional rhinosurgery: a prospective study.

The aim of this study was to investigate the changes in nasal airways after Le Fort I osteotomy and functional rhinosurgery. 49 patients were included in this study to assess intranasal anatomical and functional changes resulting from a Le Fort I osteotomy. The data were classified according to the three-dimensional positioning of the maxilla: in group I the maxilla was impacted; in group II the maxilla was inferior; and in group III only sagittal maxillary movement was performed. Presurgical and 5 months postsurgical rhinological inspection, anterior rhinomanometry and acoustic rhinometry were carried out. Additional rhinosurgery, such as resection of the inferior concha or septoplastic intervention, was performed to avoid functional problems in nasal breathing, particularly when the maxilla was impacted. Rhinomanometric assessment showed a significant improvement in nasal breathing in the whole group and each single group. Acoustic rhinometry revealed an increase in typical cross-sectional intranasal areas. The authors conclude that concerns about the respiratory consequences of this surgical procedure appear unwarranted when functional rhinosurgery is undertaken concomitantly, particularly in patients with increased preoperative nasal airway resistance.

A comparison of the COG and MCNP codes in computational neutron capture therapy modeling, Part I: boron neutron capture therapy models.

The goal of this study was to evaluate the COG Monte Carlo radiation transport code, developed and tested by Lawrence Livermore National Laboratory, for neutron capture therapy related modeling. A boron neutron capture therapy model was analyzed comparing COG calculational results to results from the widely used MCNP4B (Monte Carlo N-Particle) transport code. The approach for computing neutron fluence rate and each dose component relevant in boron neutron capture therapy is described, and calculated values are shown in detail. The differences between the COG and MCNP predictions are qualified and quantified. The differences are generally small and suggest that the COG code can be applied for BNCT research related problems.

A comparison of the COG and MCNP codes in computational neutron capture therapy modeling, Part II: gadolinium neutron capture therapy models and therapeutic effects.

The goal of this study was to evaluate the COG Monte Carlo radiation transport code, developed and tested by Lawrence Livermore National Laboratory, for gadolinium neutron capture therapy (GdNCT) related modeling. The validity of COG NCT model has been established for this model, and here the calculation was extended to analyze the effect of various gadolinium concentrations on dose distribution and cell-kill effect of the GdNCT modality and to determine the optimum therapeutic conditions for treating brain cancers. The computational results were compared with the widely used MCNP code. The differences between the COG and MCNP predictions were generally small and suggest that the COG code can be applied to similar research problems in NCT. Results for this study also showed that a concentration of 100 ppm gadolinium in the tumor was most beneficial when using an epithermal neutron beam.

[Distraction in mouth, jaw and facial surgery]. / Distraktion in der Mund-, Kiefer- und Gesichtschirurgie.

Distraction osteogenesis is established worldwide as a new surgical technique. The former rule, not to osteotomize before the end of bone growth, is no longer valid. Today, distraction starts as early as infancy as well as in childhood and adolescence. This new method allows the gain of bone in the distraction gap so that bone grafting can be avoided. Distraction is indicated in hemifacial microsomias, multiple syndromes with mandibular malformations, mandibular retrognathia, posttraumatic jaw deficiencies, craniofacial malformations, alveolar ridge resorptions, and alveolar ridge resections. Distraction surgery started in the mandible and was continued in the maxilla and the craniofacial region. Alveolar ridge distraction followed. After using extraoral devices, the development of internal applicable distractors followed. Today, bi- or tridirectional internal devices are already available. The whole treatment concept includes the orthodontist. Distraction planning before surgery is of great importance. The literature presently includes methods, indications, and case reports but only few results, which we compare with our experiences.

Vertical distraction of a free vascularized fibula flap in a reconstructed hemimandible: case report.

The authors report a case of vertical distraction osteogenesis of a free revascularized fibula flap used to reconstruct an hemimandible lost as a result of a gunshot injury. The reconstruction procedure and the distraction protocol are described; clinical and radiological results are presented. The vertical discrepancy between the fibula and the native right hemimandible was corrected.

[Improving the contour and preserving the profile of the lower third of the face]. / Konturverbesserung und Profilerhalt des unteren Gesichtsdrittels.

Aesthetic surgery of the lower third of the face is divided up into five clinically relevant problem regions: nasolabial folds, lips, chin, mandibular angle including horizontal ramus and neck. Surgical correction is be described in the international literature. The pathophysiological conditions that lead to aesthetic problems in the lower third of the face are explained. Based on this, the indications for different methods of correction, which include soft and bony tissue of the face, are explained. The results of our own clinical experience, dependent on alloplastic material, are presented with all the advantages and disadvantages.

Human bone cell phenotypes differ depending on their skeletal site of origin.

This report describes skeletal site-related differences in human osteoblastic cell metabolism in studies of four patients. Northern analyses of the constitutive growth factor messenger ribonucleic acid (mRNA) expression pattern in mandibular and iliac crest-derived human osteoblastic cells (based on within-patient comparisons) revealed higher mRNA levels for strong mitogenic growth factors such as basic fibroblast growth factor (bFGF) and insulin-like growth factor II (IGF-II) in the rapidly proliferating and less alkaline phosphatase (ALP)-expressing mandibular osteoblastic cells compared to those in the lower bFGF and IGF-II mRNA levels in slowly proliferating iliac human osteoblastic cells exhibiting a higher ALP expression level. In contrast, transforming growth factor-beta (TGF beta) mRNA was more abundant in iliac human osteoblastic cells than in mandibular osteoblastic cells. Furthermore, we found that there was a proportionality, based on data from both sites, between the level of constitutive TGF beta mRNA and the response to exogenously administered bFGF or IGF-II. A comparable pattern of growth characteristics and mRNA expression was also observed in transformed human osteoblastic cells that had been subcloned in sublines expressing high and low levels of the human osteoblastic differentiation marker ALP. These findings are consistent with 1) skeletal site-related differences in human bone cell phenotypes, and 2) decreased IGF-II and bFGF expression and increased TGF beta expression and responsiveness to bFGF and IGF-II in human bone cells exhibiting a high ALP expression.

[Does the use of miniplates for fracture treatment influence mandibular growth? An experimental animal study]. / Beeinflusst die Frakturversorgung mit Osteosyntheseplatten das Wachstum des Unterkiefers? Eine tierexperimentelle Studie.

The mandibles of 2-month-old rats were artificially fractured and then stabilised with miniplates. The experiments lasted until growth was concluded in the animals. We found an inhibition of mandibular growth due to both the trauma and the operation. The growth retardation due to fracture was increased by the operation. The growth inhibition was directly proportional to the severity of trauma and operation.

[One-stage procedure for bimaxillary correction of extremely severe malocclusions. Pretreatment, planning and operation methods with functionally stable fixation of upper and lower jaws]. / Einzeitige bimaxilläre Korrektur extremer Fehlbisse. Vorbehandlung, Planung und Operationsmethode mit funktionsstabiler Fixierung im Ober- und Unterkiefer.

The comprehensive treatment of extremely severe malocclusion, carried out up to now in more than 30 patients, is described step by step. After the removal of the third molars, orthodontic treatment is provided to align the arches. This is followed by 4 weeks of bite plane treatment to bring back the TMJ condyles into their physiologic position, which is usually lost because of the undefined occlusal relationship. Following cephalometric analysis the surgical treatment plan is established on the basis of lateral cephalometric films aimed at orthognathic repositioning of the mandible and the maxilla. In addition, the one-stage bimaxillary correction is simulated in the articulator for the construction of occlusal splints. The intraoperative use of these splints and the fixation of the condyles at the zygomatic bone via positioning plates allows, for the first time, the reproducible physiologic adjustment of the condyle during the entire length of the operation. This method also permits three-dimensional control of the position of the repositioned maxilla. The functionally stable fixation of maxilla and mandible makes long-term postoperative immobilization unnecessary.

[Conclusiveness of various diagnostic procedures for squamous cell carcinomas of the visceral cranium and the oral cavity as compared with histological evaluations]. / Aussagekraft verschiedener Diagnoseverfahren bei Plattenepithelkarzinomen von Gesichtsschädel und Mundhöhle im Vergleich zur histologischen Auswertung.

In 60 patients with primary squamous cell carcinomas of the oral cavity, clinical examination was complemented by 5 additional diagnostic procedures prior to surgery to assess tumor extension. Comparing these finding with the histological evaluation of the excised tissue demonstrated that, while the TNM classification remains the foundation of all tumor diagnostic procedures, the use of radiography, bone scintigraphy and CT is indispensable to ascertain the amount of tissue to be excised. CT competes with B-scan sonography in cervical lymph node diagnostics. Tumor scintigraphy has been found to be an unreliable method.

[Effects of different sterilizing techniques on osseous regeneration of grafted lyophilized cartilage]. / Einfluss unterschiedlicher Sterilisationsverfahren auf die ossäre Regeneration allogener gefriergetrockneter Knorpelimplantate.

The suitability of variably sterilized lyocartilage grafts as potential bone substitutes was investigated in animal experiments with special attention to configurational stability. In 3 Beagles corticocancellous implant beds were prepared by box-type ostectomies and lyophilized costal cartilage blocks sterilized with X-rays,ethylene oxide gas and beta-propriolactone solution were placed into them. Implants sterilized with X-rays and beta-propriolactone appeared to be unsuited for recontouring facial bone defects, since they showed complete loss of configuration after a follow-up time of 125 and 230 days, respectively. By contrast, cartilage implants sterilized with ethylene oxide gas retained their configuration after no less than 328 days. In light of these results, methods for sterilizing other biomaterials should be re-considered.

Behavior of differently sterilized allogenic lyophilized cartilage implants in dogs.

The behavior of beta-propriolactone-sterilized, radiation-sterilized, and gas-sterilized lyophilized cartilage implants was histiologically investigated at various intervals up to 328 days. Beta-propriolactone-sterilized lyophilized cartilage implants were completely resorbed after 230 days and had only undergone partial osseous substitution. The radiation-sterilized lyophilized cartilage implants behaved similarly after 125 days. Despite partial resorption of the gas-sterilized lyophilized cartilage after 328 days, constant form was maintained and complete bony substitution of the resorbed regions had occurred in each case.