Ralf Dammer

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.

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.

Pigmented peripheral nerve sheath tumor of the oral cavity with expression of AP-2β and c-RET: A case report

Pigmented peripheral nerve sheath tumor of the oral cavity is a rare lesion and may be difficult to distinguish clinically from true melanocytic tumors. We report a case of pigmented peripheral nerve sheath tumor with a high degree of melanocytic differentiation and describe its histologic and ultrastructural features. Immunohistochemistry and polymerase chain reaction findings support the neural crest origin of the tumor. The clinical course of our case indicates that local recurrence may be a significant problem in pigmented peripheral nerve sheath tumor.

In vitro application of optical transmission systems in erbium:YAG laser temporomandibular joint surgery

The experimental setup of this study is focused on the changes in temporomandibular joint tissue after irradiation with an Erbium:YAG laser. Initially, the free-running beam from the laser was focused onto freshly excised porcine tissue samples, indicating an optimum average energy density and pulse duration for the purpose of temporomandibular joint surgery of about 15 - 60 J/cm2 and 120 microsecond(s) - 240 microsecond(s) , respectively. Consecutively, an attempt was made to couple the Erbium:YAG laser beam on the one hand to optical fibers made of infrared-transmitting glasses (fluoride- and chalcogenide-based), on the other hand to a recently developed sapphire and liquid core fiber, respectively. From the preliminary observations of this investigation it appears that both the liquid core and the sapphire fiber are the most promising candidates for delivery of Erbium-YAG laser radiation in arthroscopic surgery of the craniomandibular articulation.

Experimental investigations of the use of an erbium:YAG laser on temporomandibular joint (TMJ) structures: first experimental results

The following paper introduces the results of an interdisciplinary research project. With the aid of photomacroscopic examination, light and scanning electron microscope investigations, changes to temporomandibular joint structures were detected in vitro after irradiation with an Erbium:YAG laser system. The solid-state Erbium:YAG laser, operating at a wavelength of 2.94 micrometers was used in the normal- spiking mode. The free-running laser beam was focussed onto freshly excised porcine tissue samples using a 108-mm sapphire lens. In this study the output was generally pulsed at a repetition rate of 4 Hz, with a pulse duration varying from 120 microsecond(s) to 500 microsecond(s) . Between 50 mJ and 500 mJ per pulse were applied to create pinpoint lesions. The optimum average energy density and pulse duration of the Erbium:YAG laser radiation for the purpose of TMJ-surgery (as far as it concerns meniscus and articulating facets) - which means efficient etch rate and minimal adjacent injury - seems to be about 24-42 J/cm2 and 120 microsecond(s) -240 microsecond(s) , respectively.