Herbert Niederdellmann

Computer-assisted bone segment navigation

Computer-assisted bone segment navigation is defined as the precise 3-D positioning of geometrically mapped and mathematically described skeletal segments. These bone segments are osteotomized, fractured or prefabricated according to a surgical plan. The high-precision positioning should have an accuracy of 1 mm or better. Segment navigation should be prepared with plain computed tomography (CT) without the implantation of registration markers before CT in order to reduce the number of CTs and operations. The Surgical Segment Navigator (SSN) was developed at the University of Regensburg with the support of Carl Zeiss. This is the first system to meet these criteria. The SSN is based on an infrared positioning device which is connected to a Hewlett Packard LD Pro Workstation. Infrared transmitters are connected to individual templates which are fixed to the bone segment by osteosynthesis screws. Intraoperative correlation between surgical planning and surgical site is achieved by use of a surface-pattern of the bone segment which fits equally well to the laboratory model and the conditions encountered in the patient. The concept of the SSN was submitted by Carl Zeiss as German Patent DE 19747427 A1 in 1997. The SSN system presented here has already been applied clinically and its precision has been evaluated by bone segment navigation in human cadavers.

Surgical planning of computer-assisted repositioning osteotomies.

Repositioning osteotomies are frequently used in orthopedic surgery and traumatology to correct malpositions. Computed tomography (CT), stereolithographic models, and x-rays are used in planning. However, the precision achieved in the planning phase is usually not translated to patients. The Surgical Segment Navigator (SSN) is a navigation system that allows computer-assisted correction of malpositions. It consists of an infrared positioning device, two dynamic reference frames (DRF), an infrared pointer, and an infrared camera. All data are displayed numerically and graphically on the monitor of the SSN workstation. The Laboratory Unit for Computer-Assisted Surgery (LUCAS) is used for planning surgery in the laboratory. LUCAS requires only a native CT scan. A preparatory operation to implant bone markers that will be visible in x-rays and a further planning CT scan showing the bone markers, which were necessary with previous systems, are not required for the LUCAS and SSN system. This significantly reduces the radiation exposure of the patient and the costs of surgical planning. Measuring anatomical landmarks in the surgical site, which is time-consuming and reduces accuracy, is not required with the SSN system because the position of the infrared transmitters is known during surgical planning on the LUCAS workstation. This makes the surgical approach faster and much more precise. The surgical planning data are transferred to the surgical site using a data file and an individual surface pattern that fits the surface of the navigated bone segment. The data file is exported from the LUCAS-workstation to the SSN workstation. The planned spatial displacement of the infrared transmitters is saved in this file. The individual surface pattern carries the infrared transmitters. This pattern is the mechanical interface between infrared transmitters and navigated bone segment. The individual surface pattern can be polymerized directly on a small stereolithographic model of the navigated bone segment. The surface pattern can also be generated as negative form from a CT data set using a computer-assisted design/manufacture system. In summary, LUCAS and SSN allow for the computer-assisted correction of malpositions and positioning of artificial joints and implants. In principle, the systems can be used in all fields of surgery.

Solitary Lag Screw Osteosynthesis in the Treatment of Fractures of the Angle of the Mandible: A Retrospective Study

Various methods have been advocated for the treatment of fractures of the angle of the mandible, emphasizing the complexity of the problem. A functionally stable osteosynthesis can be achieved in such fractures with a solitary lag screw. This technique meets the principles of rigid internal fixation and achieves maximum stability with a minimum of implant material. It obviates the need for maxillomandibular fixation, as well as the morbidity associated with the conventional methods of treatment. A review is presented of 50 patients who were treated by this method. The data show that the procedure is an effective and predictable modality of treatment with a low rate of morbidity.

Conservative or radical treatment of keratocysts: a retrospective review

The paper reports our experience in the treatment of keratocysts and make recommendations for treatment in the form of a retrospective study. Thirty-eight patients with 52 keratocysts out of a total of 318 patients with 351 odontogenic cysts who presented between 1984 and 1992 were analysed. Outcome was measured by recurrence and there were three recurrences (6%) which compares favourably with published reports in which figures of up to 62% have been quoted. Based on the experience of others as well as our own series we recommend that small cysts near the alveolar process should be treated by simple excision, but large invasive cysts near the base of the skull should be treated by radical resection leaving a margin of normal tissue around the specimen. If any variables are discovered that can reliably indicate prognosis we may be able to revise these recommendations.

Long-term results after primary restoration of the orbital floor

It has been possible to follow-up 74 (54%) of the 137 patients who were treated for orbital floor fractures in our clinic between 1988 and 1992. The minimum observation time was 12 months. The results of the orbital reconstruction were analysed on the basis of the postoperative findings and the advantages of access via a central lower lid incision and the use of allogenic dura mater, were evaluated on the basis of the functional results. The biocompatibility, stability and ready availability of allogenic dura mater all support its use in orbital floor restoration. Nevertheless, the potential problems of CJD transmission are discussed.

Technical improvements in the sagittal split ramus osteotomy

This article addresses the potential sources of morbidity associated with the sagittal split ramus osteotomy. Refinements in the instrumentation and technique are described; these enhance the exactness of the procedure, thereby minimizing the complications and improving the stability of the surgical result.

Maxillomandibular fixation with minihooks: a clinical evaluation

This article provides the clinical evaluation of a simple but effective method of maxillomandibular fixation that eliminates the morbidity attendant to the conventional methods of maxillomandibular fixation. The indications have been defined on the basis of the clinical experience with this technique.

Evidence of intrafamilial variability of CBFA1/RUNX2 expression in cleidocranial dysplasia--a family study.

AbstractAim: To investigate the phenotypical expression of an identical mutation of the CBFA1/RUNX2 gene within a family with cleidocranial dysplasia. Patients and Method: A five-member family underwent clinical examination.Two members, father and son, showed dissimilar symptoms of cleidocranial dysplasia. The two affected patients were examined for syndrome-typical symptoms, and the genotype was determined by molecular-genetic analysis. Results: In both patients an identical missense mutation (G146R) in exon 2 of the CBFA1/RUNX2 gene was identified. In father and son the dental disturbances were similarly clearly expressed. However, the craniofacial skeleton of the son exhibited fewer dysostotic ossification features than that of the father. In the three clinically healthy family-members no mutation of the CBFA1/RUNX2 gene was found. Conclusion: In two patients with cleidocranial dysplasia an identical missense mutation in the CBFA1/RUNX2 gene leading to a divergent craniofacial phenotype was determined. The results indicate marked variability in the phenotypical expression of CBFA1/RUNX2 mutations.ZusammenfassungZiel: Das Ziel dieser Untersuchung bestand darin, die phänotypische Expression einer identischen Mutation des CBFA1/RUNX2-Gens innerhalb einer Familie mit Dysostosis cleidocranialis zu analysieren. Patienten und Methode: Eine fünfköpfige Familie mit zwei Betroffenen wurde klinisch untersucht. Zwei Familienmitglieder, Vater und Sohn, wiesen in unterschiedlichem Umfang Symptome der Dysostosis cleidocranialis auf. Die beiden betroffenen Patienten wurden hinsichtlich der syndromtypischen Symptomatik befundet und er Genotyp molekulargenetisch bestimmt. Ergebnisse: Bei beiden Betroffenen gelang der Nachweis einer Punktmutation (G146R) in Exon 2 des CBFA1/RUNX2-Gens. Bei Vater und Sohn waren die Störung des Zahnsystems gleichermaßen deutlich ausgeprägt. Das kraniofaziale Skelett des Sohnes war jedoch in geringerem Umfang mit dysostostotischen Ossifikationsmerkmalen behaftet als das des Vaters. Bei den drei klinisch unauffälligen, direkt mit dem Vater verwandten Familenmitgliedern konnte keine Mutation des CBFA1/RUNX2-Gens festgestellt werden. Schlussfolgerung: Bei zwei Patienten mit Dysostosis cleidocranialis konnte eine identische Missensemutation im CBFA1/RUNX2-Gen nachgewiesen werden. Diese führte zu einem unterschiedlichen kraniofazialen Phänotyp. Die Ergebnisse weisen auf eine hohe Variabilität in der phänotypischen Expression von CBFA1/RUNX2-Mutationen hin.

Suchttherapie alkohol- und nikotinkranker Patienten mit Karzinomen im Kopf-Hals-Bereich

Alkohol- und Nikotinabusus spielen in der Ätiopathogenese oraler Karzinome eine zentrale Rolle. In der vorliegenden Studie sollte geprüft werden, wie groß die Anzahl der Patienten mit oralen/oropharyngealen Karzinomen ist, die regelmäßig Alkohol und Nikotin konsumieren, und wie auf das Suchtverhalten therapeutisch reagiert wird. An 105 Patienten mit oralen bzw. oropharyngealen Plattenepithelkarzinomen (90 Männer, 15 Frauen) wurden anhand katamnestischer Erhebungen und eines speziellen Fragebogens die Trink- und Rauchgewohnheiten untersucht (Vergleichsmaßstab 40 g Alkohol/Tag Männer, 20 g Alkohol/Tag Frauen – entspricht „Alkoholgefährdung“). Bei Rauchern wurde die Anzahl der Packungsjahre zugrundegelegt und mit klinischen (Tumorgröße, Lokalisation) und laborchemischen Daten (γ-GT) verglichen. Besondere Aufmerksamkeit galt dem Suchtverhalten vor und nach Tumortherapie (Erfassung frühestens 1 Jahr nach erfolgreicher Tumortherapie). Zum Zeitpunkt der Diagnosestellung tranken 83,1% regelmäßig Alkohol (71,9% über 20 bzw. 40 g Alkohol/Tag), nach der Therapie stellten 17,9% den Alkoholkonsum ein. Die Expositionszeit lag bei 59,8% der Alkoholiker, mit einem täglichen Konsum oberhalb des Schwellenwerts, über 20 Jahre. 70% der Patienten waren „reine“ Biertrinker. Tabakkonsum bestand zu 92,7% aus Zigaretten. Prätherapeutisch gaben 89,7% der Patienten an, zu rauchen, postoperativ nur noch 37,8%. Mundbodenkarzinome zeigten eine Prävalenz bei Alkohol- und Nikotinabusus. 84% der Patienten mit einem T3- und T4-Karzinom lagen über dem oben genannten Alkoholschwellenwert. Keiner der 105 Patienten ist gezielt einer Suchttherapie zugeführt worden. Angesichts der hohen Prävalenz von alkohol- und nikotinabhängigen Patienten mit Mundhöhlenkarzinomen muß im Sinn einer tertiären Prophylaxe von Rezidiven, Zweitkarzinomen und zur Verbesserung der Lebensqualität bzw. sozialen Rehabilitation obligatorisch eine Entzugstherapie angestrebt werden. Vor weitergehenden Therapien, z.B. mit Retinoiden, ist eine erfolgreiche Entzugstherapie zu fordern. Alcohol and nicotine abuse play a major role in the etiology of oral squamous cell carcinomas. In the present study, we investigated the number of patients with oral/oropharyngeal carcinomas who regularly consume alcohol and nicotine and what type of specific treatment should be prescribed for the addiction. A total of 105 patients (90 men, 15 women) with oral/oropharyngeal squamous cell carcinomas were studied based on catamnestic data as well as a special questionnaire designed to assess drinking and smoking habits (40 g alcohol/day for men and 20 g alcohol/day for women was taken as the standard measure for those considered at risk for alcoholism). For smokers, the number of packs smoked per year was determined and compared to clinical data (i.e., tumor size, location) and laboratory data (γ-GT). Particular attention was given to the addiction behavior before and after tumor therapy (recorded at least 1 year after successful tumor treatment). At the time of diagnosis, 83.1% regularly drank alcohol (71.9% reported drinking over 40 g/ 20 g of alcohol per day). Another 17.9% stopped drinking after therapy. Of the alcoholics 59.8% had been exposed to a daily consumption level above the threshold amount for more than 20 years. Some 70% of the patients reported that they exclusively drank beer. Tobacco consumption came from cigarette smoking 92.7% and 89.7% reported that they smoked before therapy – after therapy only 37.8% smoked. Carcinomas of the floor of the mouth indicated a prevalence toward alcohol and nicotine abuse. Of the patients with a T3 and T4 carcinoma 84% had daily alcohol consumption levels over the threshold value stated above. None of the 105 patients underwent specific alcohol treatment therapy. In light of the high prevalence of carcinomas of the oral cavity in patients with alcohol and nicotine addiction, mandatory withdrawal therapy should be offered in the form of postoperative treatment to prevent recurrence or the development of second primary tumors, as well as to improve the quality of life and encourage social rehabilitation. Before further treatment, for example, with retinoids, a successful withdrawal treatment should be completed.

Immunzytochemische Venenblutuntersuchungen an Patienten mit manifesten Mundhöhlenkarzinomen, oralen Präkanzerosen, benignen Tumoren und chronisch alkoholkranken Patienten

In a prospective pilot study we investigated the percentage of immunocompetent cells in the peripheral blood in 146 patients (lymphocytes, leucocytes, monocytes, T cells, B cells, NK cells, T-helper cells, T-suppressor cells, ratio T-helper/T-suppressor cells, activated T cells HLA-DR) by flow cytometry. The immunologic parameters were derived from patients with oral and oropharyngeal squamous cell carcinomas, precancerous lesions and benign tumours and from a group of heavy smokers and alcoholics. Carcinoma patients (n = 46) were compared with risk groups and a reference group consisting of patients with inflammatory disease. Within the collective of carcinoma patients we measured the immune status before and after chemo-, radio- and operative therapy. We also analysed the immune parameters in relation to clinical and histomorphological parameters (TNM status, grading). The univariate analysis of monocytes showed significant relationships between on the one hand carcinoma patients and on the other alcoholics and those with benign tumours and precancerous lesions. In precancerous lesions NK cells were significantly increased compared with alcoholics and the reference group. A significant decrease in B cells in carcinoma patients may show incipient insufficiency of the humoral immunity. The immune parameters showed a different reaction depending on therapy. After irradiation we found a significant increase of T-suppressor cytotoxic cells and decreases in B and T-helper cells. Chemotherapy showed an increase in T and T-helper cells and a decrease in B cells. Surgical therapy alone yielded an increase in B cells. The comparison of all pre- and posttherapeutic parameters showed significant changes only in activated T cells HLA-DR. We found no correlation between prognostic clinico-pathological factors and immune parameters. No changes were found in a multivariate analysis.In einer prospektiven Pilotstudie wurden aus Veneblut von insgesamt 146 Patienten Lymphozyten Leukozyten, Monozyten, T-Zellen, B-Zellen, NK-Zellen, T-Helferzellen, T-Suppressorzellen, Ratio-T-Helfer- und T-Suppressorzellen Flow-zytophotometrisch von Patienten mit oralen und oropharyngealen Karzinomen, Präkanzerosen, benignen Tumoren im Kopf-Hals-Bereich, einer Gruppe von alkoholkranken und nikotinabhängigen Patienten sowie einer Referenzgruppe bestimmt und verglichen. Von den Karzinompatienten (n=46) wurden der Immunstatus vor und nach der operativen bzw. Chemo-, Radio- und Kombinationstherapie ermittelt und einander gegenüber gestellt. Weiterhin wurden Korrelationen zu T-, N-, M-Status, Tumorstadium und Grading geprüft. Bei univariater Analyse haben wir signifikante Unterschiede bei den Monozyten der Karzinompatienten im Vergleich zu Alkoholikern, benignen Tumoren und Präkanzerosen festgestellt. Die NK-Zellen waren nur bei Präkanzerosepatienten im Vergleich zu Alkoholikern und der Referenzgruppe erhöht. Ein signifikanter Abfall des Anteils der B-Zellen im Blut von Karzinompatienten könnte auf eine Insuffizienz der humoralen Immunität hindeuten. Die Immunparameter reagierten therapieabhängig sehr differenziert. Insbesondere kam es zum Anstieg der T-Suppressor-zytotoxischen Zellen nach Bestrahlung, während die T-Helfer- und B-Zellen erwartungsgemäß abfielen. Nach Polychemotherapie stiegen T-Zellen und T-Helferzellen signifikant an, die B-Zellen fielen ab. Im Gegensatz dazu führte die chirurgische Therapie zum Anstieg der B-Zellen. Der Vergleich aller prätherapeutischen mit allen posttherapeutischen Parametern ergab lediglich einen signifikanten Unterschied bei den aktivierten T-Zellen HLA-DR. Keine Abhängigkeiten fanden sich zwischen den klinisch pathohistologischen Faktoren und den Immunzellen. Im multivariaten Vergleich waren keine signifikanten Unterschiede nachweisbar. In a prospective pilot study we investigated the percentage of immunocompetent cells in the peripheral blood in 146 patients (lymphocytes, leucocytes, monocytes, T cells, B cells, NK cells, T-helper cells, T-suppressor cells, ratio T-helper/T-suppressor cells, activated T cells HLADR) by flow cytometry. The immunologic parameters were derived from patients with oral and oropharyngeal squamous cell carcinomas, precancerous lesions and benign tumours and from a group of heavy smokers and alcoholics. Carcinoma patients (n=46) were compared with risk groups and a reference group consisting of patients with inflammatory desease. Within the collective of carcinoma patients we measured the immune status before and after chemo-, radio- and operative therapy. We also analysed the immune parameters in relation to clinical and histomorphological parameters (TNM status, grading). The univariate analysis of monocytes showed significant relationships between on the one hand carcinoma patients and on the other alcoholics and those with benign tumours and precancerous lesions. In precancerous lesions NK cells were significantly increased compared with alcoholics and the reference group. A significant decrease in B cells in carcinoma patients may show incipient insufficiency of the humoral immunity. The immune parameters showed a different reaction depending on therapy. After irradiation we found a significant increase of T-suppressor cytotoxic cells and decreases in B and T-helper cells. Chemotherapy showed an increase in T and T-helper cells and a decrease in B cells. Surgical therapy alone yielded an increase in B cells. The comparison of all pre- and posttherapeutic parameters showed significant changes only in activated T cells HLA-DR. We found no correlation between prognostic clinico-pathological factors and immune parameters. No changes were found in a multivariate analysis.