Klaus W. Grätz

Should titanium miniplates be removed after bone healing is complete

A prospective study of 32 patients was performed to analyze black pigmentation in the soft tissue covering titanium miniplates. This soft tissue was compared with the soft tissue covering Champy stainless steel plates. All plates were removed 8 months after application. Macroscopically visible pigmentation was found in 25.6% of the soft tissue covering titanium miniplates and in none of the soft tissue covering Champy stainless steel plates. Microscopically visible pigmentation was found in 71.8% of the soft tissue covering titanium miniplates and in 65.3% of the soft tissue covering Champy stainless steel plates. Energy-dispersive x-ray analysis of the soft tissue covering titanium miniplates revealed only the presence of titanium dioxide. In the soft tissue near Champy stainless steel plates, chromium, nickel, iron, and molybdenum were found. Electron microscopy showed titanium dioxide to be mainly deposited between the collagen fibers, whereas stainless steel particles were mainly found in giant cells.

Osteoradionecrosis of the mandible: Minimized risk profile following intensity-modulated radiation therapy (IMRT)

Background and Purpose:Osteoradionecrosis (ON) of the mandible is a serious late complication of high-dose radiation therapy for tumors of the oropharynx and oral cavity. After doses between 60 and 72 Gy using standard fractionation, an incidence of ON between 5% and 15% is reported in a review from 1989, whereas in more recent publications using moderately accelerated or hyperfractionated irradiation and doses between 69 and 81 Gy, the incidence of ON is between < 1% and ~ 6%. Intensity-modulated radiation therapy (IMRT) is expected to translate into a further important reduction of ON. The aim of this descriptive study was to assess absolute and relative bone volumes exposed to high IMRT doses, related to observed bone tolerance.Patients and Methods:Between December 2001 and November 2004, 73 of 123 patients treated with IMRT were identified as subgroup “at risk” for ON (> 60 Gy for oropharyngeal or oral cavity cancer). 21/73 patients were treated in a postoperative setting, 52 patients underwent primary definitive irradiation. In 56 patients concomitant cisplatin-based chemotherapy was applied. Mean follow-up time was 22 months (12–46 months). Oral cavity including the mandible bone outside the planning target volume was contoured and dose-volume constraints were defined in order to spare bone tissue. Dose-volume histograms were obtained from contoured mandible in each patient and were analyzed and related to clinical mandible bone tolerance.Results:Using IMRT with doses between 60 and 75 Gy (mean 67 Gy), on average 7.8, 4.8, 0.9, and 0.3 cm3 were exposed to doses > 60, 65, 70, and 75 Gy, respectively. These values are substantially lower than when using three-dimensional conformal radiotherapy. The difference has been approximately quantified by comparison with a historic series. Additional ON risk factors of the patients were also analyzed. Only one grade 3 ON of the lingual horizontal branch, treated with lingual decortication, was observed.Conclusion:Using IMRT, only very small partial volumes of the mandibular bone are exposed to high radiation doses. This is expected to translate into a further reduction of ON and improved osseointegration of dental implants.Hintergrund und Ziel:Die Osteoradionekrose (ON) des Unterkiefers ist eine schwerwiegende Komplikation kurativer normofraktionierter Radiotherapie von Oropharynx- und Mundhöhlenkarzinomen. Nach Dosen zwischen 60 und 72 Gy besteht gemäß den Angaben einer Übersicht aus dem Jahr 1989 eine ON-Inzidenz von 5–15%, während laut neueren Arbeiten über leicht akzelerierte oder hyperfraktionierte Behandlungsschemata mit Dosen von 69–81 Gy die ON-Inzidenz zwischen < 1% und ca. 6% beträgt. Intensitätsmodulierte Radiotherapie (IMRT) dürfte die ON-Rate weiter reduzieren. Ziel dieser deskriptiven Arbeit war, absolute und relative Knochenvolumina mit hoher Dosisexposition zu evaluieren und in Beziehung zur beobachteten Knochentoleranz der eigenen Patienten nach IMRT-Behandlung zu setzen.Patienten und Methodik:Zwischen Dezember 2001 und November 2004 wurden an der eigenen Klinik 123 Patienten mit Tumoren der Kopf-Hals-Region mit IMRT behandelt; hiervon waren 73 einer Untergruppe von Patienten mit Risiko für ON zuzurechnen (Karzinome des Oropharynx oder der Mundhöhle und Herddosen > 60 Gy). 21 Patienten wurden postoperativ, 52 primär kurativ bestrahlt; 56 erhielten eine simultane cisplatinbasierte Chemotherapie. Die mittlere Beobachtungszeit betrug 22 Monate (12–46 Monate). Die Mundhöhle inkl. Kieferknochen außerhalb des Planungszielvolumens wurde konturiert, und Dosis-Volumen-Bedingungen zur Organschonung wurden festgelegt. Retrospektiv wurde für jeden Patienten das gesamte Kieferknochenvolumen konturiert, und die Dosis-Volumen-Histogramme wurden im Hinblick auf die klinische Knochentoleranz ausgewertet.Ergebnisse:Durch IMRT in Dosen zwischen 60 und 75 Gy (Mittelwert 67 Gy) wurden im Mittel 7,8, 4,8, 0,9 und 0,3 cm3 einer Dosis von > 60, 65, 70 und 75 Gy ausgesetzt (Tabelle 1 und Abbildung 1). Diese Werte sind deutlich kleiner als nach konventioneller Bestrahlung. Der Unterschied wurde im Vergleich mit einer historischen Serie näherungsweise quantifiziert (Abbildung 3). Zusätzliche Risikofaktoren der eigenen Patienten wurden analysiert (Abbildung 2). Nur ein ON-Ereignis (Grad 3) im Bereich des lingualen Horizontalasts der Mandibula wurde beobachtet und erfolgreich mit einer lingualen Dekortikation behandelt.Schlussfolgerung:Mittels IMRT werden nur sehr kleine Knochenvolumina hohen Bestrahlungsdosen ausgesetzt. Durch diese Knochenschonung werden eine weitere Reduktion des ON-Risikos und eine höhere Erfolgsrate rekonstruktiver Zahnimplantate (Tabelle 2) erwartet.

Bone healing in the rat and dog with nonglycosylated BMP-2 demonstrating low solubility in fibrin matrices.

A novel form of recombinant human bone morphogenetic protein‐2 (BMP‐2) was explored for effective incorporation and long‐term retention into fibrin ingrowth matrices. The solubility of native BMP‐2 is greatly dependent on its glycosylation. To enhance retention of BMP‐2 in fibrin matrices, a nonglycosylated form (nglBMP‐2), which is less soluble than the native glycosylated protein, was produced recombinantly and evaluated in critical‐size defects in the rat calvarium (group n = 6). When 1 or 20 μg nglBMP‐2 was incorporated by precipitation within the matrix, 74 ± 4% and 98 ± 2% healing was observed in the rat calvarium, respectively, as judged radiographically by closure of the defect at 3 weeks. More soluble forms of BMP‐2, used as controls, induced less healing, demonstrating a positive correlation between low solubility, retention in vitro, and healing in vivo. Subsequently, the utility of nglBMP‐2 was explored in a prospective veterinary clinical trial for inter‐carpal fusion in dogs, replacing the standard‐of‐care, namely autologous cancellous autograft, with nglBMP‐2 in fibrin. In a study of 10 sequential canine patients, fibrin with 600 μg/ml nglBMP‐2 performed better than autograft in the first weeks of bone healing and comparably thereafter. Furthermore, a greater fraction of animals treated with nglBMP‐2 in fibrin demonstrated bone bridging across each of the treated joints at both 12 and 17 weeks than in animals treated with autograft. These results suggest that evaluation in a human clinical setting of nonglycosylated BMP‐2 in fibrin matrices might be fruitful.

Factors influencing survival of free-flap in reconstruction for cancer of the head and neck: a literature review.

Microvascular free tissue transfer is a reliable technique for head and neck reconstruction with success rates of 90–99%. Currently, there is no consensus concerning antithrombotic agents, antibiotics, or monitoring techniques. Therefore, the aim of this study was to review current literature dealing with microvascular free‐tissue transfer and factors influencing the outcome. In addition to excellent microsurgical techniques, coupling devices are a promising new technique, but are not useful in all arteries. Antibiotics should be given in three doses, as a more lengthy dosage time seems to have no advantage. The risk for elderly patients can be best assessed by the American Society of Anesthesiologists (ASA) score, but early mobilization, including intense chest physiotherapy, is important. Anticoagulation can be considered in cases of small vessels, significant size mismatch, vein graft, or vessels of poor quality. Monitoring should be done hourly during the first 24 hours and then every 4 hours for the next 2 postoperative days.

Impact of whole body positron emission tomography on initial staging and therapy in patients with squamous cell carcinoma of the oral cavity

The aim of this study is to evaluate the additional clinical information provided by whole body positron emission tomography (PET) with fluorodeoxyglucose (FDG) for initial staging of patients with squamous cell carcinoma (SCC) of the oral cavity. PET scans from the head to the pelvic floor of 34 consecutive patients (22 male, 12 female; mean age 71 years) with histologically confirmed SCC of the oral cavity were retrospectively evaluated. Clinical information including CT of the head and neck and chest X-Ray or chest CT was compared with information on nodal involvement and distant metastases or secondary tumours obtained with PET. The primary tumour was identified with PET in 33 of 34 patients (97%). In 27 Patients (81%) the clinical N-stage was confirmed with PET. In two Patients (6%) additional pathologic loco-regional lymph nodes were found. In five patients more lymph nodes were identified with CT. Distant lesions were seen with PET imaging in bone, lung, mediastinum, liver and colon. In three patients (6%) distant metastases were correctly identified. In another four patients (12%) a secondary cancer was detected. One false positive finding was described with PET. In five of 34 patients (15%) the additional findings as revealed with PET lead to a change of treatment. Whole body PET provides relevant additional information to a standard clinical staging procedure in patients with oral cavity SCC. The detection of distant metastases and secondary primary tumours can have a great impact on patient management.

Osteoradionecrosis of the Mandible

Background and Purpose:Osteoradionecrosis (ON) of the mandible is a serious late complication of high-dose radiation therapy for tumors of the oropharynx and oral cavity. After doses between 60 and 72 Gy using standard fractionation, an incidence of ON between 5% and 15% is reported in a review from 1989, whereas in more recent publications using moderately accelerated or hyperfractionated irradiation and doses between 69 and 81 Gy, the incidence of ON is between < 1% and ~ 6%. Intensity-modulated radiation therapy (IMRT) is expected to translate into a further important reduction of ON. The aim of this descriptive study was to assess absolute and relative bone volumes exposed to high IMRT doses, related to observed bone tolerance.Patients and Methods:Between December 2001 and November 2004, 73 of 123 patients treated with IMRT were identified as subgroup “at risk” for ON (> 60 Gy for oropharyngeal or oral cavity cancer). 21/73 patients were treated in a postoperative setting, 52 patients underwent primary definitive irradiation. In 56 patients concomitant cisplatin-based chemotherapy was applied. Mean follow-up time was 22 months (12–46 months). Oral cavity including the mandible bone outside the planning target volume was contoured and dose-volume constraints were defined in order to spare bone tissue. Dose-volume histograms were obtained from contoured mandible in each patient and were analyzed and related to clinical mandible bone tolerance.Results:Using IMRT with doses between 60 and 75 Gy (mean 67 Gy), on average 7.8, 4.8, 0.9, and 0.3 cm3 were exposed to doses > 60, 65, 70, and 75 Gy, respectively. These values are substantially lower than when using three-dimensional conformal radiotherapy. The difference has been approximately quantified by comparison with a historic series. Additional ON risk factors of the patients were also analyzed. Only one grade 3 ON of the lingual horizontal branch, treated with lingual decortication, was observed.Conclusion:Using IMRT, only very small partial volumes of the mandibular bone are exposed to high radiation doses. This is expected to translate into a further reduction of ON and improved osseointegration of dental implants.Hintergrund und Ziel:Die Osteoradionekrose (ON) des Unterkiefers ist eine schwerwiegende Komplikation kurativer normofraktionierter Radiotherapie von Oropharynx- und Mundhöhlenkarzinomen. Nach Dosen zwischen 60 und 72 Gy besteht gemäß den Angaben einer Übersicht aus dem Jahr 1989 eine ON-Inzidenz von 5–15%, während laut neueren Arbeiten über leicht akzelerierte oder hyperfraktionierte Behandlungsschemata mit Dosen von 69–81 Gy die ON-Inzidenz zwischen < 1% und ca. 6% beträgt. Intensitätsmodulierte Radiotherapie (IMRT) dürfte die ON-Rate weiter reduzieren. Ziel dieser deskriptiven Arbeit war, absolute und relative Knochenvolumina mit hoher Dosisexposition zu evaluieren und in Beziehung zur beobachteten Knochentoleranz der eigenen Patienten nach IMRT-Behandlung zu setzen.Patienten und Methodik:Zwischen Dezember 2001 und November 2004 wurden an der eigenen Klinik 123 Patienten mit Tumoren der Kopf-Hals-Region mit IMRT behandelt; hiervon waren 73 einer Untergruppe von Patienten mit Risiko für ON zuzurechnen (Karzinome des Oropharynx oder der Mundhöhle und Herddosen > 60 Gy). 21 Patienten wurden postoperativ, 52 primär kurativ bestrahlt; 56 erhielten eine simultane cisplatinbasierte Chemotherapie. Die mittlere Beobachtungszeit betrug 22 Monate (12–46 Monate). Die Mundhöhle inkl. Kieferknochen außerhalb des Planungszielvolumens wurde konturiert, und Dosis-Volumen-Bedingungen zur Organschonung wurden festgelegt. Retrospektiv wurde für jeden Patienten das gesamte Kieferknochenvolumen konturiert, und die Dosis-Volumen-Histogramme wurden im Hinblick auf die klinische Knochentoleranz ausgewertet.Ergebnisse:Durch IMRT in Dosen zwischen 60 und 75 Gy (Mittelwert 67 Gy) wurden im Mittel 7,8, 4,8, 0,9 und 0,3 cm3 einer Dosis von > 60, 65, 70 und 75 Gy ausgesetzt (Tabelle 1 und Abbildung 1). Diese Werte sind deutlich kleiner als nach konventioneller Bestrahlung. Der Unterschied wurde im Vergleich mit einer historischen Serie näherungsweise quantifiziert (Abbildung 3). Zusätzliche Risikofaktoren der eigenen Patienten wurden analysiert (Abbildung 2). Nur ein ON-Ereignis (Grad 3) im Bereich des lingualen Horizontalasts der Mandibula wurde beobachtet und erfolgreich mit einer lingualen Dekortikation behandelt.Schlussfolgerung:Mittels IMRT werden nur sehr kleine Knochenvolumina hohen Bestrahlungsdosen ausgesetzt. Durch diese Knochenschonung werden eine weitere Reduktion des ON-Risikos und eine höhere Erfolgsrate rekonstruktiver Zahnimplantate (Tabelle 2) erwartet.

Precision and accuracy of the 3dMD photogrammetric system in craniomaxillofacial application.

Background: In modern anthropometry of such complex structures as the face, three-dimensional scanning techniques have become more and more common. Before establishing them as a criterion standard, however, meticulous evaluation of their precision and accuracy under both ideal and clinical circumstances is essential. Potential sources of error need to be identified and addressed. Materials and Methods: Under ideal circumstances, a phantom is used to examine the precision and accuracy of the 3dMD system. A clinical setting is simulated by varying different parameters such as angle, distance, and system reregistration, as well as data evaluation under different levels of magnification. Results: The handling of the system was unproblematic in matters of data acquisition and data analysis. It was very reliable, with a mean global error of 0.2 mm (range, 0.1-0.5 mm) for mannequin head measurements. Neither the position of the head nor that of the camera influenced these parameters. New referencing of the system did not influence precision and accuracy. Conclusions: The precision and accuracy of the tested system are more than sufficient for clinical needs and greater than those of other methods, such as direct anthropometry and two-dimensional photography. The evaluated system can be recommended for evaluation and documentation of the facial surface and could offer new opportunities in reconstructive, orthognathic, and craniofacial surgery.

Osteoradionecrosis of the Mandibula in Patients Treated with Different Fractionations

Purpose:The incidence of osteonecrosis of the mandibula (ON) after irradiation using modern three-dimensional planning as well as hyperfractionation or moderately accelerated irradiation has been evaluated and compared with the incidence of the preceding period.Patients and Methods:The records of 268 head and neck cancer patients irradiated between January 1, 1980 and December 31, 1998 with a dose to the mandibula of at least 60 Gy were retrospectively analyzed. All patients had CT-based treatment planning, computerized dose calculation with isodose charts also in several off-axis planes, and regular verification films.Results:The long-term cumulative incidence of ON needing mandibular resection was as follows: after conventional fractionation 6.2% (between 60 and 66.6 Gy target dose) or 20.1% (between > 66.6 and 72 Gy); after hyperfractionated irradiation with a target dose between 72 and 78.8 Gy 6.6%; after concomitant boost irradiation according to the MDA/Houston regime with a dose between 63.9 and 70.5 Gy: no case; after 6 × 2 Gy/week or 7 × 1.8 Gy/week and a total target dose between 66 and 72 Gy approximately 17% or higher (small patient number).Conclusion:Comparison of the incidence of ON during the period between 1980 and 1990 with the following period between 1990 and 1998 shows a decrease in risk to a value of approximately 5% using modern three-dimensional techniques as well as hyperfractionation or moderately accelerated fractionation.Ziel:Die Inzidenz von Osteonekrosen (ON) der Mandibula nach Radiotherapie im Bereich von Mundhöhle und Pharynx nach Anwendung moderner dreidimensionaler Bestrahlungsplanung und veränderten Fraktionierungen wurde ermittelt und mit den Erfahrungen der unmittelbar vorausgegangenen Periode verglichen.Patienten und Methodik:Es handelt sich um eine retrospektive Analyse der Inzidenz von Mandibulanekrosen bei 268 Patienten mit Karzinomen der Mundhöhle oder des Pharynx, die zwischen dem 01.01.1980 und dem 31.12.1998 im Rahmen einer primären oder postoperativen Radiotherapie eine Dosis von mindestens 60 Gy auf die Mandibula erhalten hatten (Tabelle 1). Alle Patienten erhielten eine CT-unterstützte computerisierte Bestrahlungsplanung mit Isodosenkarten auch in mehreren Ebenen außerhalb des Zentralstrahls und regelmäßigen Feldkontrollaufnahmen.Ergebnisse:Die kumulative Inzidenz einer mit Mandibularesektion behandelten ON nach Bestrahlung betrug nach konventioneller Fraktionierung (Abbildung 1a) 6,2% (60–66,6 Gy) bzw. 20,1% (> 66,6–72 Gy), nach hyperfraktionierter Bestrahlung (Abbildung 1c) mit 72–78,8 Gy 6,6%; nach akzelerierter Bestrahlung (Abbildung 1b) gemäß dem Schema des MDA-Hospitals in Houston, TX, USA, mit einer Dosis von 63,9–70,5 Gy wurde keine ON beobachtet, während nach 6 × 2 Gy/Woche bzw. 7 × 1,8 Gy pro Woche und einer Gesamtdosis zwischen 66 und 72 Gy etwa 17% ON beobachtet wurden.Schlussfolgerung:Ein Vergleich der Inzidenz von ON der Mandibula nach Anwendung moderner dreidimensionaler Bestrahlungsplanung und hyperfraktionierter oder mäßig akzelerierter Bestrahlung mit gleichzeitigem Boost nach dem Schema des MDA-Hospitals zeigt gegenüber der Inzidenz in der vorausgegangenen Periode zwischen 1980 und etwa 1987 einen Rückgang auf Werte von etwa 5% (Tabelle 2).

Staging of head and neck tumors: [18F]fluorodeoxyglucose positron emission tomography compared with physical examination and conventional imaging modalities

PURPOSE The aims of this study were to evaluate the use of [(18)F]fluorodeoxyglucose positron emission tomography (FDG-PET) in the staging of primary and recurrent tumors of the head and neck in comparison to routine clinical methods (physical examination, ultrasonography, computed tomography) and to investigate the effect of FDG-PET scanning on therapeutic strategy. MATERIALS AND METHODS Retrospective analysis of the results of FDG-PET and conventional diagnostic modalities were compared with biopsy results or patient outcome or both. In a period of 6 years, 78 FDG-PET studies were performed on 56 patients; 24 of them before therapy and 54 on suspicion of residual or recurrent tumor. The evaluation of the diagnostic results was performed separately for the primary site and the nodal sites of the neck and for tumor occurrence in the trunk. RESULTS In detecting the primary site, FDG-PET results reached a sensitivity of 93%, a specificity of 100%, and an accuracy of 94%. In detecting the nodal sites, similar results of 94%, 97%, and 96% were seen, respectively. In detecting tumor occurrence in the trunk, results were 83%, 100%, and 98%, respectively. The McNemar test did not prove any statistically significant difference between FDG-PET and the evaluated conventional methods. When used in conjunction with conventional diagnostic tests, 22% of the PET scans gave important additional information. Finally, 11% of the performed PET scans led to a change in therapeutic planning. CONCLUSIONS Our results show that FDG-PET is a reliable method to detect tumors in all tumor sites. Therefore, we recommend that FDG-PET scanning be performed routinely as a first diagnostic step in pretherapeutic staging of patients with biopsy-proven head and neck cancer.

Frontal sinus fractures : principles of treatment and long term results after sinus obliteration with the use of lyophilized cartilage

The most commonly used techniques for frontal sinus obliteration involve the implantation of an autogenous tissue graft: either fat, muscle or bone. Lyophilized allogenic cartilage due to its unique properties, such as the tendency to ossification and resistance to volume reduction, can be used as the material of choice for sinus obliteration. A clinical and radiological study of 66 patients operated on for frontal sinus fractures, between January 1 1988 through December 31 1995 was undertaken. Variables recorded included the aetiological factors, the clinical and radiological fracture features with the corresponding treatment modality, the association of frontal sinus fractures with intracranial involvement, the early and late postsurgical complications and the correlation between pre- and postoperative radiological findings. Obliteration of the frontal sinus with lyophilized cartilage chips was performed in 51 (77.3%) patients. The postsurgical evaluation showed no major complications. Revision of the frontal sinus was only required in one patient. The radiological findings verified the progressive calcification of the obliterated sinus. Allogenic lyophilized cartilage implantation offers distinct advantages in cases of severe frontal sinus trauma: 1. There is nearly unlimited availability of the material. 2. There is no need for a second operation field with the associated potential donor site morbidity. 3. The operation time is reduced due to the avoidance of a second operation on the donor site.