Peter Kessler

Long-term results of distraction osteogenesis of the maxilla and midface

Since the beginning of 1998, eight patients have been treated by osteodistraction to correct hypoplasia of the maxilla and midface of various origins. Among them were five patients who were treated by high LeFort I osteotomies and insertion of subcutaneous intraoral distraction devices in the malar region. In the remaining three patients, extraoral distraction devices were applied after LeFort II and III osteotomies. Distraction osteogenesis was successful in all cases, resulting in a mean sagittal bone gain measured parallel to the skull base of 9.0 mm (range 4.5-12.0) in the group treated with intraoral distractors and a mean of 20.3 mm in the extraoral distraction group (range 15.0-25.0). All patients were kept under orthodontic supervision before, during, and after osteodistraction. Long-term cephalometric and clinical evaluation after a mean follow-up period of 24 months in the intraoral distraction group (range 22-26) and 12 months in the extraoral distraction group (range 10-14) show stable results concerning the skeletal and dental relations. Long-term follow-up is necessary.

Effects of osteoinduction on bone regeneration in distraction: Results of a pilot study *

Rate and frequency of distraction as well as stimulatory effects transmitted by growth factors and local gene therapy have a decisive influence on bone regeneration. In a pilot study we tested the effect of four different morphogenetic and mitotic proteins and a genetically transferred vector system on bone healing in continuous osteodistraction in a large animal experiment on 24 Goettingen mini-pigs. For this purpose bone morphogenetic protein (BMP-2), BMP-7, TGF-beta, IGF-1 and a liposome vector were instilled into the distraction gap. The animals were killed after 1-4 weeks of consolidation. Histological and radiological evaluations showed maximum bone formation after the application of BMP-2/7, whereas the application of TGF-beta, IGF-1 and the liposomal vector had only a limited effect on bone regeneration. The quantitative analysis demonstrated an average amount of bone in the distraction gap of 50% and 61% after instillation of BMP-2 and 7, respectively. The BMP-2 expression, however, was maximal after induction with the non-viral vector. Only after BMP-2/7 application could physical, radiographic and histological evidence of bone union be detected. In bone distraction with a short observation period the application of morphogenetic proteins seems to enhance bone regeneration significantly. Before application in humans further studies are necessary to measure the dose-effect relationship, the mode of application and the efficacy of different inductive proteins. The combination of osteodistraction with osteoinduction, however, could shorten treatment times dramatically.

Static and dynamic periosteal elevation: a pilot study in a pig model

The osteoinductive potential of periosteum and bone can be stimulated by elevating the periosteum in a distraction-like modus, but also by an ad-hoc elevation. This was tested and proved in an experiment in 9 Goettingen mini-pigs with elevation heights of 5, 10 and 15mm. Specially designed and perforated titanium meshes were implanted subperiosteally to compare the dynamic elevation procedure with static shielding. The cumulative results for bone formation underneath the mesh were 66% in dynamic and 67% in non-dynamic elevation. The cumulative results for mineralization of the bone regenerates in comparison with the underlying basal bone of the skull showed independently from the technique applied no difference bigger than 5%. No major difference in bone formation could be observed in this pilot study. The main advantages of dynamic periosteal elevation and static shielding are minimal invasion and morbidity. Periosteal elevation could be applied in cranio-maxillofacial surgery, in preimplantological augmentation and in reconstructive surgery of the skull; applications in other specialties may be possible.

Minimally invasive neck surgery. Surgical feasibility and physiological effects of carbon dioxide insufflation in a unilateral subplatysmal approach

Endoscopically assisted, minimally invasive techniques to regions without a natural cavity require insufflation with carbon dioxide (CO2). In the neck region this may impair hemodynamics, blood gas homoeostasis, cerebral blood circulation and increase the intracranial pressure. An exclusively endoscopic unilateral subplatysmal approach to the submandibular region was investigated in nine mini-pigs randomized to three groups. On both neck sides, within a 14 day interval, the subplatysmal space was inflated with CO2 at 10 mmHg, 20 mmHg (1.33/2.66 x 10 (3)Pa) or 20 mmHg (2.66 x 10 (3)Pa) combined with mechanical suspension. Data for hemodynamic and blood gas parameters, gas volumes, and intracranial pressure were obtained preoperatively, 30 min after onset and 10 min postopeatively. In a pocket created by insufflation of 20 mmHg (2.66 x 10 (3)Pa), exposition and resection of the submandibular gland were accomplished easily. The elevation procedure had technical disadvantages. The mean operation time was 48.9 min. Unilateral subplatysmal carbon dioxide insufflation of the submandibular neck region up to 20 mmHg (2.66 x 10 (3)Pa) did not affect physiological parameters. As an exclusive endoscopical approach for unilateral surgery of the submandibular region, the use of inflation pressures of up to 20 mmHg (2.66 x 10 (3)Pa) might be considered.

Riesenzellgranulom und Osteitis fibrosa cystica bei Hyperparathyreoidismus

Zu ossären Läsionen des Kiefers mit ähnlichem histologischen Bild gehören das zentrale Riesenzellgranulom und braune Tumoren bei Hyperparathyreoidismus. Da auch der radiologische Befund dieser Erkrankungen nahezu identische Merkmale aufweist, ist die differenzialdiagnostische Abgrenzung schwierig. Liegen zusätzlich maligne Grunderkrankungen vor, ist die Abgrenzung von ossären Metastasen ein zusätzliches Problem. Es wird über zwei Patienten mit osteolytischen Läsionen der Maxilla berichtet. In beiden Fällen lag eine maligne Grunderkrankung (Prostatakarzinom, Mammakarzinom) vor, die Zuweisung erfolgte jeweils wegen des Verdachts auf ossäre Metastasierung. Klinisch fanden sich identische Befunde. Die Biopsie zeigte riesenzellhaltige Läsionen des Knochens, wodurch die zunächst vermutete Metastasierung ausgeschlossen werden konnte. Bei einem der Patienten war im Labor der massiv erhöhte Parathormonspiegel auffällig. Aufgrund der raschen Größenprogression wurde initial eine chirurgische Therapie durchgeführt. Im Rahmen der weitergehenden Diagnostik konnte bei diesem Patienten ein Adenom der Nebenschilddrüsen festgestellt werden. Eine kausale Therapie wurde eingeleitet. Die beiden geschilderte Fälle demonstrieren die Schwierigkeiten bei der Differenzialdiagnostik der Riesenzellläsionen des Kiefers. Eine exakte Diagnostik ist für die Einleitung einer adäquaten Therapie jedoch unumgänglich. Die einzelnen Krankheitsbilder werden hier im Zusammenhang mit den notwendigen diagnostischen und therapeutischen Maßnahmen gegenübergestellt. Giant cell lesions of the bone present similar histological features. The differential diagnosis comprises central giant cell granuloma, giant cell tumor of bone, and osteitis fibrosa cystica (brown tumor) in combination with hyperparathyroidism. Since these lesions may mimic metastatic bone disease in patients with a history of cancer, a malignant process has to be considered. Since the treatment and prognosis of these entities—benign versus malignant osteolytic bone processes—differ greatly, definitive differential diagnosis is of utmost importance. Two patients presenting with osteolytic lesions of the maxilla are reported here. In both cases a history of cancer (breast and prostate) suggested bone spreading of these malignant tumors. The clinical and histological findings were similar in both patients. One lesion was diagnosed as central giant cell granuloma, the other was found to be brown tumour in osteitis fibrosa cystica as an initial manifestation of hyperparathyroidism. The presented cases demonstrate the difficulties in establishing the correct diagnosis of patients found to have osteolytic lesions of the jawbones which is critical for the appropriate management of these patients. The article discusses the different entities of osteolytic lesions of the jawbones and the necessary diagnostic and therapeutic approach.

Endoskopisch unterstützte LeFort-I-Osteotomie bei Distraktionsverfahren im Oberkiefer

Fragestellung. Untersucht wurde die Eignung minimalinvasiver, endoskopisch unterstützter chirurgischer Verfahren bei LeFort-I-Osteotomien in Kombination mit Distraktionsbehandlungen zur Kompensation transversaler und sagittaler Wachstumsdefizite. Patienten. Vor der Anwendung an 3 Patienten wurde das technische Vorgehen zunächst an 4 Körperspendern erprobt und trainiert. Als Zugang zur LeFort-I-Ebene bot sich ein transantrales Vorgehen durch die Kieferhöhle an. Nach 1 cm kurzen, vertikalen Inzisionen im Oberkiefervestibulum konnte der Oberkiefer bei 3 Patienten sinuskopisch kontrolliert in der LeFort-I-Ebene mit geraden und abgewinkelten Metallmeißeln osteotomiert werden. In 2 Fällen wurde eine chirurgisch unterstützte, mediane Osteotomie der Maxilla zur transversalen Dehnung durchgeführt, in 1 Fall ein Mittelgesichtsdistraktor zur sagittalen Distraktion des Oberkiefers eingesetzt. Ergebnisse. In allen Fällen gelang es, endoskopisch unterstützt über die Kieferhöhle die Höhe der LeFort-I-Ebene zu identifizieren, darzustellen und in dieser Ebene eine Osteotomie durchzuführen. Im Fall der Mittelgesichtsdistraktion wurde paranasal ein subkutan gelegener Distraktor fixiert, dessen Distraktorgehäuse im unteren Nasengang eingebracht werden konnte. Die Distraktionsbehandlungen verliefen erfolgreich. Schlussfolgerungen. Die Kombination aus endoskopisch unterstützter Osteotomie und Distraktionsbehandlung erwies sich als viel versprechende Erweiterung minimalinvasiver Operationstechniken gerade bei noch im Wachstum befindlichen Individuen. Purpose. The purpose of this study was to demonstrate the feasibility of combining a minimally invasive endoscopic approach to the maxilla with transverse and sagittal distraction procedures. Materials and methods. Four human cadavers were used for training of a minimally invasive access to the maxilla to perform an endoscopically assisted Le Fort I osteotomy, before this technique was applied in three patients with transverse and sagittal growth deficits of the maxilla. Access to the maxilla was gained through a small mucosa incision in the vestibule to create a visualization port to the maxillary sinus through a bur hole. Landmarks were identified through the endoscope before a Le Fort I osteotomy was performed using straight and angulated chisels of different form and angulation. In two patients, the maxilla was split sagittally to perform a transverse maxillary expansion. In one patient, a buried distractor was applied close to the piriform aperture to correct a sagittal growth deficit in a hypoplastic maxilla. Results. The endoscopic exposure of the maxillary sinus walls from within the sinus, the accurate identification of landmarks, and the creation of a Le Fort I osteotomy was achieved in all cases. Distractor application close to the piriform aperture rendered good stability. Conclusion. The results of these case reports indicate that the endoscopic approach to the maxillary sinus allows excellent exposure of the sinus walls to perform an endoscopically assisted Le Fort I osteotomy. The combination of endoscopy and osteodistraction supports the trend toward minimally invasive, less traumatic surgical procedures, especially in individuals still growing.

3D-imaging for the assessment of volume changes of the human face

It was the aim of the study to determine the accuracy of the assessment of volume changes of a non-contact, non-invasive, optical 3D-imaging method in vitro and in vivo for patients, who underwent mid-facial distraction.