Josip Bill

Stereolithography in oral and maxillofacial operation planning

Stereolithography (STL) is a method of organ-model-production based on computed tomography scans which enables the representation of complex 3-dimensional anatomical structures. Surfaces and internal structures of organs can be produced by polymerization of UV-sensitive liquid resin using a laserbeam. In oral and maxillofacial surgery this technique is advantageous for reconstruction of severe skull defects because a more accurate preoperative planning is possible. Using recently developed software we are able to reconstruct unilateral bony defects by virtual mirror imaging of the contralateral side and production of a STL mirror model as well as the reconstruction of non-mirrorable defects by superposition. Advantages of STL are the representation of complex anatomical structures, high precision and accuracy, and the option to sterilize the models for intraoperative use. More accurate planning using this method improves postoperative results, decreases risks and shortens treatment time.

Repair of human skull defects using osteoinductive bone alloimplants

To estimate the efficacy of cranioplasty in clinical practice, autolyzed, antigen-extracted, allogenic (AAA) bone was prepared from cortical bones of human organ donors. AAA bone implants consisted of completely demineralized bone powder, completely demineralized pliable bone chips, surface-demineralized bone chips with pliable crevices, surface-demineralized rigid bone chips, or combinations thereof. 21 patients received AAA bone cranioplasties and were followed-up for between 12 and 58 months (average: 29 months). No infection or rejection of any of the AAA bone implants occurred. X-ray assessments as well as bone scintigraphies revealed osseous integration and remodelling of the AAA bone implants with minimal resorption, with the exception of completely demineralized AAA bone chips which showed partial resorption (2 cases). However, the partial resorption of completely demineralized AAA bone chips ceased after the implants had been remodelled. In 4 cases, the osteosynthesis material was removed between 10 and 18 months after the cranioplasty. In another case, a re-entry was necessary because of recurrence of an intracranial tumor. All of these five AAA bone reconstructions showed bleeding surfaces and osseous consolidations at the time of re-entry. A bone biopsy taken from one of these cranioplasties showed osteoinduction on the surface of the AAA bone implants. This first clinical review of cranial reconstructions using osteoinductive AAA bone implants emphasizes the therapeutical application of AAA bone for cranioplasty. Large AAA bone chips from human skull bones facilitate the reproduction of the skulls convexity especially when combined with preoperative stereolithography-based planning.

Treatment of patients with cleft lip, alveolus and palate – a short outline of history and current interdisciplinary treatment approaches

Clefts of lip, alveolus and palate have been known for a long time. First tangible evidence of surgical therapy in terms of cheiloplasty, however, does not date further back than the 4th century after Christ. It was Werner Hagedorn from Magdeburg who laid the foundations of geometrical anatomical surgical lip repair in 1884. The procedures designed by LeMesurier, Tennison, Randall or Millard in the 1950s, and by Pfeifer in 1970 are part of todays cleft therapy applied by the different schools of surgery.

Vergleichende Untersuchungen zur Sinusbodenelevation mit autogenem oder allogenem Knochengewebe

Zusammenfassung Bei 63 Patienten wurden 82 Sinusbodenelevationen durchgeführt. Als Augmentationsmaterial wurden in 39 Fällen autogener Knochen vom Beckenkamm (bei 16 Sinusbodenaugmentationen in Kombination mit einer absoluten Alveolarkammerhöhung) und in 43 Fällen osteoinduktives, allogenes Knochenpulver [AAA-Knochen (autolysierter, Antigen-extrahierter, allogener Knochen): n = 8, DFDBA (demineralized freeze-dried bone allograft) und/oder Grafton TM (demineralized bone matrix gel): n = 35] verwendet. Bei den osteoinduktiven, allogenen (demineralisierten) Knochenimplantaten war 4–6 Monate nach der Implantation eine radiologisch sichtbare Verschattung als Zeichen der Knochenneubildung sichtbar. Histologisch konnte eine vollständige Umwandlung der osteoinduktiven Knochenimplantate in patienteneigenes Knochengewebe nachgewiesen werden. Die durchschnittlich erzielte Augmentationshöhe betrug bei autogenen Knochentransplantaten 14 (± 3) mm gegenüber 9 (± 3) mm bei allogenem Knochenpulver. Bezüglich der Knochenqualität konnte sowohl histologisch als auch radiologisch kein Unterschied zwischen den beiden Augmentationsmaterialien festgestellt werden. Sinuskopische Kontrolluntersuchungen zeigten bei beiden Gruppen reizlose Schleimhautverhältnisse. Im Mittel wurden bei beiden Gruppen 2 enossale Dentalimplantate (Bone Lock ® oder ITI ® -Vollschraubenimplantate) in den augmentierten Sinusboden inseriert. Bei der Beckenkammgruppe zeigten 4 von 67 Implantaten und bei den allogenen Knochenimplantaten 2 von 74 Dentalimplantaten keine Osseointegration. Die durchschnittlichen postoperativen Beschwerden betrugen in der Beckenkammgruppe 19 (± 9) Tage (ohne Berücksichtigung von 2 Patienten mit Beschwerden über mehr als 90 Tage) gegenüber 3 (± 5) Tage bei den Empfängern von allogenen Knochenimplantaten. 13 Patienten, welche sich einem ambulanten Sinuslift mit allogenem Knochenpulver unterzogen hatten, waren bereits wenige Stunden nach dem Eingriff beschwerdefrei. Unter kritischer Würdigung aller erhobenen Parameter sind osteoinduktive Knochenimplantate zur Sinusbodenelevation autogenen Knochentransplantaten vom Beckenkamm in den Fällen vorzuziehen, in denen keine zusätzliche Augmentation des Alveolarkamms notwendig ist. Summary In 63 patients, 82 elevations of the maxillary sinus were performed. As augmentation, materials autografts from the iliac crest (combined with alveolar ridge augmentations in 16 sinus lifts) were transplanted in 39 cases and osteoinductive, allogeneic bone powder (AAA bone (autolyzed, antigen-extracted, allogeneic bone): n = 8, DFDBA (demineralized freeze-dried bone allograft) and/or GraftonTM (demineralized bone matrix gel): n = 35) were used in 43 cases. Some 4–6 months after implantation, osteoinductive, allogeneic (demineralized) bone implants showed radio-opaque areas as an equivalent of bone formation. Histological examinations revealed that osteoinductive implants were completely transformed into patients’ own bone tissue. The average augmentation height after autograft transplantations was 14 (± 3) mm in comparison with 9 (± 3) mm after allograft implantations. Histologically as well as radiologically no differences of the bone quality could be determined between the two augmentation materials. Endoscopic controls showed, in both groups, nonirritated mucous membranes. On an average 2 endosseous implants (Bone LockR or ITIR-screw implants) were inserted into the augmentated maxillary sinus floors in both groups. No osseointegration was achieved in 4 out of 67 dental implants when bone autografts were used and in 2 out of 74 dental implants of the allogeneic bone group. Patients with bone autografts suffered from postoperative complaints on an average of 19 (± 9) days (without consideration of 2 patients with postoperative complaints persisting for more than 90 days). The average postoperative complaints of recipients of allogeneic bone implants continued for 3 (± 5) days. The 13 patients who underwent an ambulant sinus lift procedure with allogeneic bone powder were already symptom-free several hours after the operation. Under critical consideration of all investigated parameters, osteoinductive bone implants are preferable to iliac bone autografts for maxillary sinus augmentations in those cases in which no additional alveolar ridge augmentation is required.

Die bimaxilläre Osteotomie mit und ohne Kondylenpositionierung—eine Langzeitstudie 1981–2002

Mit der Einführung der Vier-Splint-Positionierungstechnik bei bimaxillären Osteotomien 1997 in unserem Hause wurde die gewünschte reproduzierbare zentrische Kondylenpositionierung mit Berücksichtigung der Autorotation des Unterkiefers und Vermeidung einer Stufenbildung im Unterkieferosteotomiebereich ermöglicht. Im Zeitraum von 1981 bis 2002 erfolgte bei 622 Patienten die bimaxilläre Osteotomie. Hiervon wurde in den Jahren 1981–1997 bei 395 Patienten (63,5%) der Eingriff ohne oder nur mit Kondylenpositionierung im Rahmen der sagittalen Ramusosteotomie, in den Jahren 1997–2002 bei 227 Patienten (36,5%) mit durchgehender Kondylenpositionierung in der Vier-Splint-Technik durchgeführt. Es konnte festgestellt werden, dass es bei vorbestehenden Funktionsstörungen nach einem Eingriff mit durchgehender Kondylenpositionierung zu einer statistisch signifikanten (p<0,05) Verringerung funktioneller Störungen kam im Vergleich zu der Gruppe ohne durchgehende Kondylenpositionierung. Die Ergebnisse bestätigen aus unserer Sicht die Indikationsstellung zur Kondylenpositionierung bei bimaxillären Osteotomien. The introduction of the four-splint technique in our hospital in 1997 made possible the reproducible centric condyle positioning in bimaxillary osteotomies, while taking the autorotation of the mandible into consideration and avoiding steps in the mandibular osteotomy line. From 1981 to 2002 a total of 622 patients underwent bimaxillary osteotomy surgery. During 1981–1997 a total of 395 patients (63.5%) underwent surgery without or only with centric condyle positioning in sagittal ramus osteotomy of the mandible. During 1997–2002 a total of 227 patients (36.5%) underwent surgery with continuous centric condyle positioning with the four-splint technique. In patients with preoperative functional disorders, surgery with continuous centric condyle positioning resulted in statistically significant (p<0.05) improvement compared to those who underwent surgery without continuous centric condyle positioning. The results confirm the indication for continuous centric condyle positioning in bimaxillary osteotomies.

Orthognathic surgery in cleft patients

Orthognathic surgery has become a standard procedure in cranio-maxillo-facial surgery during the past five decades. Based upon the elementary works by Obwegeser who introduced sagittal split ramus osteotomy in the early 1950s, this procedure has become the worldwide gold standard in mandibular orthognathic procedures by now. When devices for ensuring the centric condylar position throughout the entire surgery were introduced by Luhr in the early 1980s, modern understanding of complete functional rehabilitation in orthognathic surgery was further enhanced. Even though Le Fort I osteotomy was performed by Wassmund already in the 1920s, it took almost another 50 years until this procedure became accepted in surgery, mainly due to concerns for severe haemorrhage that may occur during surgery. Application of a compound condylar positioning device which was established to ensure and keep the exact condylar position throughout maxillary, mandibular, as well as during bimaxillary osteotomies, and to permit the targeted use of distraction devices. Among those, cleft patients also sometimes need orthognathic correction of typical micrognathia and pseudoprogenia in late adolescence or at early adult age as secondary cleft surgery procedures. In this overview, special emphasis will be placed on orthodontic treatment as well as on the technical prerequisites for the surgical procedure.

Histological and histomorphometric study of growth-related changes of cranial sutures in the animal model

INTRODUCTION During the early development, numerous histological and morphometric changes occur in the cranial sutures the exact knowledge of which is of fundamental significance for understanding clinically relevant cranial anomalies. In this paper a histological and histomorphometric longitudinal study of the coronal, sagittal and lambdoid sutures in the rat is reported in relation to age. MATERIAL AND METHODS Forty-eight male Wistar rats (Rattus norvegicus Berkenhout) were raised under standard conditions. Eight animals each were sacrificed at defined time points (10, 14, 28, 42, 70, 98 days post partum) for specimen preparation. Histological preparations of the sagittal, coronal and lambdoid sutures were produced and examined morphologically and histomorphometrically (suture width, height, and area). RESULTS Histologically, three phases of sutural growth with characteristic structural features were found. Histomorphometry reveals a quasi linear increase in height from the 30th to the 98th day post partum. Suture width remained relatively constant in the area of dura mater and periosteum. CONCLUSION The sutures of the test animals studied had a similar growth behaviour primarily consisting of an increase in height with almost constant width. The three-phases of development could be demonstrated histologically in all sutures.

Orale Rehabilitation von Tumorpatienten mit enossalen Implantaten

Zusammenfassung Im Rahmen einer prospektiven Studie sollte der Einfluß des Zustands der periimplantaren Hart- und Weichgewebe auf den Implantationserfolg bei Tumorpatienten untersucht werden. Aus 59 Tumorpatienten, die zwischen Juli 1988 und August 1996 mit 261 Implantaten versorgt worden waren, wurde ein Zielkollektiv von 23 Patienten mit 99 Implantaten ermittelt, die mindestens 1 Jahr prothetisch versorgt waren. 18 dieser Patienten litten an einem Plattenepithelkarzinom der Mundhöhle. 17 Patienten wurden präoperativ mit einer Dosis von 40 Gy radiiert. 68 von 99 Implantaten standen in zur Unterkieferrekonstruktion transplantiertem autologem Knochen. Zur Beurteilung der periimplantären Hart- und Weichgewebssituation wurden der Hygieneindex, der Sulcusblutungsindex, der Gingivaindex, die parodontale Sondierungstiefe, der periimplantäre Knochenabbau und das Dämpfungsverhalten der Implantate herangezogen. Das Kollektiv der Tumorpatienten wurde mit einem Kollektiv gesunder Implantatpatienten verglichen. Tumorpatienten zeigten eine signifikant schlechtere Situation bezüglich der erhobenen periimplantären Parameter als gesunde Implantatpatienten. Ein signifikanter Einfluß auf den Implantationserfolg konnte nur für die periimplantäre Taschentiefe nachgewiesen werden. Im Zielkollektiv lag die Erfolgsquote bei 77,8%. Summary In a prospective study, the influence of the status of the peri-implant hard and soft tissues on the success of enosseous dental implants in tumor patients was assessed. Out of 59 tumor patients with 261 implants, treated between July 1988 and August 1996, a pool of 23 patients with 99 implants provided with dentures for at least 1 year was obtained. Eighteen of these patients suffered from a squamous cell carcinoma of the oral cavity. Seventeen patients underwent preoperative radiation (40 Gy). A total of 68 out of 99 implants were inserted into autologous bone transplanted to reconstruct the mandible. In order to assess the peri-implant hard and soft tissues, the Hygiene Index, the Sulcus Bleeding Index, the Gingiva Index, the pocket-probing depth, the peri-implant bone resorption, and the periotest were used. The results in the tumor patients were compared with the results in a pool of nontumor patients. Tumor patients had significantly worse peri-implant parameters than nontumor patients. The peri-implant pocket-probing depth proved to have significant influence on the success rate. The overall success rate was 77.8%.In a prospective study, the influence of the status of the peri-implant hard and soft tissues on the success of enosseous dental implants in tumor patients was assessed. Out of 59 tumor patients with 261 implants, treated between July 1988 and August 1996, a pool of 23 patients with 99 implants provided with dentures for at least 1 year was obtained. Eighteen of these patients suffered from a squamous cell carcinoma of the oral cavity. Seventeen patients underwent preoperative radiation (40 Gy). A total of 68 out of 99 implants were inserted into autologous bone transplanted to reconstruct the mandible. In order to assess the peri-implant hard and soft tissues, the Hygiene Index, the Sulcus Bleeding Index, the Gingiva Index, the pocket-probing depth. the peri-implant bone resorption, and the periotest were used. The results in the tumor patients were compared with the results in a pool of nontumor patients. Tumor patients had significantly worse periimplant parameters than nontumor patients. The peri-implant pocket-probing depth proved to have significant influence on the success rate. The overall success rate was 77.8%.

Klinischer Einsatz osteoinduktiver Implantate in der kraniofazialen Chirurgie

Autolysierter, Antigen-extrahierter, allogener Knochen (AAA-Knochen) wird aus kortikalem Knochen von Multiorganspendern hergestellt und besitzt aufgrund seiner Freisetzung von knocheneigenen BMPs osteoinduktive Eigenschaften. Im Rahmen einer prospektiven Studie wurden über einen Zeitraum von mehr als 7 Jahren 37 Schädeldachdefekte mit AAA-Knochenimplantaten rekonstruiert. Die Patienten wurden standardisiert nachuntersucht. Radiologische Untersuchungen sowie Knochenszintigraphien ergaben eine Knochenintegration und Remodellierung der ehemaligen AAA-Knochenimplantate. In 1/4 der Fälle wurde ein erneuter operativer Eingriff 10–18 Monaten nach der Kranioplastik durchgeführt (Entfernung von Osteosynthesematerial, Tumorrezidiv). Alle 9 AAA-Knochen-Rekonstruktionen zeigten blutende Oberflächen und eine knöcherne Konsolidierung. Aus dem Zentrum eines dieser AAA-Knochenimplantate wurde eine Biopsie entnommen, welche eine, von der Oberfläche ausgehende, Knochenneubildung zeigte. In 1 Fall kam es zu einem infektionsbedingten Verlust eines AAA-Knochenimplantats. Dies ist insbesondere bemerkenswert, da bei ca. 1/3 der Fälle die Knochenimplantate in direktem Kontakt zur Stirnhöhle standen. Die klinischen Resultate unterstreichen eindrucksvoll den therapeutischen Nutzen von osteoinduktivem AAA-Knochen bei Schädeldachplastiken. Großflächige AAA-Knochen-Chips aus menschlichen Schädelkalotten erleichtern die Rekonstruktion in Schädelbereichen mit großer Konvexität. Dies gilt insbesondere dann, wenn ein stereolithographisches Modell des Defekts zur präoperativen Planung zur Verfügung steht. Autolyzed, antigen-extracted, allogeneic bone (AAA bone) is prepared from cortical bones of human organ donors. AAA bone possesses osteoinductive properties as it delivers BMPs from its bone matrix. Within a prospective study, 37 cranial defects were reconstructed using AAA bone implants over a period of more than 7 years. The patients were followed-up at standardized intervals. Roentgenographic assessments and bone scintigraphies revealed osseous integration and remodelling of the AAA bone implants. In one quarter of the cases re-entry was performed 10 to 18 months after the cranioplasty (removal of osteosynthesis material, recurrence of tumor). All nine AAA bone reconstructions showed bleeding surfaces and bony integrations. A bone biopsy was taken from the center of one of these AAA bone implants and this showed new bone formation originating from the surface of the implant. In one case an AAA bone implant was lost due to infection. This is noteworthy as in approximately one third of the cases the bone implants were in direct contact with the frontal sinus. The clinical results clearly emphasize the therapeutical benefit of AAA bone for cranioplasties. Large AAA bone chips from human skull bones facilitate the reconstruction of the skull’s convexity, especially when sterolithography-based operation planning is performed.Autolyzed, antigen-extracted, allogeneic bone (AAA bone) is prepared from cortical bones of human organ donors. AAA bone possesses osteoinductive properties as it delivers BMPs from its bone matrix. Within a prospective study, 37 cranial defects were reconstructed using AAA bone implants over a period of more than 7 years. The patients were followed-up at standardized intervals. Roentgenographic assessments and bone scintigraphies revealed osseous integration and remodelling of the AAA bone implants. In one quarter of the cases re-entry was performed 10 to 18 months after the cranioplasty (removal of osteosynthesis material, recurrence of tumor). All nine AAA bone reconstructions showed bleeding surfaces and bony integrations. A bone biopsy was taken from the center of one of these AAA bone implants and this showed new bone formation originating from the surface of the implant. In one case an AAA bone implant was lost due to infection. This is noteworthy as in approximately one third of the cases the bone implants were in direct contact with the frontal sinus. The clinical results clearly emphasize the therapeutical benefit of AAA bone for cranioplasties. Large AAA bone chips from human skull bones facilitate the reconstruction of the skulls convexity, especially when sterolithography-based operation planning is performed.

Langzeitergebnisse nach Korrekturoperationen am Neuro- und Viszerokranium von Patienten mit einfachen und syndromalen prämaturen Kraniosynostosen

Ziel einer retro- und prospektiv angelegten Studie war es, das kraniofaziale Wachstumsmuster bei Patienten mit isolierten und syndromalen Kraniosynostosen, insbesondere nach einem standardisierten frontoorbitalen Advancement sowie einer Mittelgesichtsvorverlagerung, klinisch und kephalometrisch zu analysieren. Bei 293 Kindern mit einem frontoorbitalen Advancement erfolgte über eine durchschnittliche Beobachtungsphase von 4,4 Jahren eine detaillierte klinische Auswertung. Aus diesem Kollektiv wurde zusätzlich bei 117 Patienten eine kephalometrische Analyse anhand seitlicher Fernröntgenbilder durchgeführt. Zudem wurden bei 36 Kindern und 8 Erwachsenen mit einem Midface-Advancement das kraniofaziale Wachstumsverhalten bzw. die Spätresultate nach einem mittleren Beobachtungszeitraum von 4,5 Jahren charakterisiert. In Abgrenzung zur linearen Kraniektomie und dem sog. Lateral-Canthal-Advancement konnte in der vorliegenden Auswertung nach dem frontoorbitalen Advancement nur bei 8,2% der Fälle (24 von 293 Patienten) eine operationspflichtige Rezidivierung gesehen werden, wobei bei isolierten Synostosierungen, wie dem Trigono- oder Plagiozephalus, überwiegend sehr gute oder gute postoperative Entwicklungen zu beobachten waren. Allerdings bestätigte die kephalometrische Analyse das begrenzte Wachstumspotential im Bereich der vorderen Schädelbasis sowie des Mittelgesichts bei syndromalen Faziokraniosynostosen. Weiterhin konnte gezeigt werden, daß das frontoorbitale Advancement die in der Syndromenreihenfolge ‘Saethre-Chotzen-Crouzon-Apert-Pfeiffer’ an Ausprägung zunehmende und kephalometrisch bekräftigte Mittelgesichtshypoplasie nur begrenzt positiv beeinflussen kann, so daß in diesen Fällen zusätzlich eine Mittelgesichtsvorverlagerung je nach Ausprägung erforderlich sein kann. Nach einem derartigen Eingriff resultierte in der vorliegenden Analyse übereinstimmend mit den Ergebnissen anderer Autoren eine hohe Rezidivierungsrate der Mittelgesichtshypoplasie bei Kindern und Heranwachsenden. Deshalb sollte die Indikation zur Le-Fort-III-Osteotomie in der Wachstumsphase eng gestellt werden. A retrospective and partly prospective study was conducted to analyse both clinically and cephalometrically the craniofacial growth pattern of patients with isolated and syndrome-related premature craniosynostosis after standardized fronto-orbital and midface advancement. The file data of 293 children with fronto-orbital advancement were evaluated over an average period of 4.4 years. In addition, lateral teleradiographies of 117 patients from this group were cephalometrically analysed. Moreover, late results of 36 children and 8 adults with midface-advancement with an average follow-up period of 4.5 years were assessed. In contrast to linear craniectomy and so-called lateral canthal advancement, in only 8.2% of cases (24 out of 293 patients) were relapses requiring reoperation found in this study after fronto-orbital advancement. The evaluations indicate that with simple forms of craniosynostosis such as trigonocephaly and plagiocephaly predominantly very good or good growth can be observed. Cephalometric evaluation confirmed the limited potential of growth in the area of the anterior skull base and in the midface in the presence of syndrome-related faciocraniosynostoses. In such cases the cephalometrically confirmed maxillary hypoplasia, which increases in severity in the following order of syndromes ‘Saethre-Chotzen-Crouzon-Apert-Pfeiffer’, could be influenced only to a limited degree by fronto-orbital advancement. For this reason midface advancement is of secondary importance in children with very severe anomalies. In the present evaluation, a high rate of relapse of midfacial hypoplasia was to be found in children and adolescents after this operation in accordance with other references. Therefore, the indication for Le Fort III osteotomy in the growth period should be limited.