[Physiological loading of the mandibular osteosynthesis: development of an improved mandibular load simulator]. / Physiologische Belastung von Unterkieferosteosynthesen: Entwicklung eines neuartigen Kieferbelastungssimulators.

Loading conditions physiologically approximating those acting on the normal masticatory system were incorporated into a new mandibular load simulator. Separate tension wires attached to each ramus of the mandible simulated the resultant force vectors of the masticatory musculature. The muscle insertion points were chosen in accordance with the anatomical situation, and the maximum in vivo forces acting on the joint. In a first application, the stability of a 2.4 mm LC-WDCP was compared with that of a 2.7 mm EDCP in plastic mandible models. It was found that under largely physiological loading, the 2.4 mm LC-EDCP exerted a stabilizing effect similar to that of a 2.7 mm EDCP. Although of smaller dimensions, the 2.4 mm LC-EDCP appears to enable an osteosynthesis of similar stability in the treatment of fractures of the mandibular angle.

A composite polymer/tricalcium phosphate membrane for guided bone regeneration in maxillofacial surgery.

The aim of the study was the development of a resorbable membrane for guided bone regeneration (GBR) with improved biocompatibility, which should be stiff enough to avoid membrane collapse during bone healing. Combining a bioactive ceramic with a resorbable polymer may improve the biocompatibility and osteoconductivity of resorbable devices. The present article describes the preparation, the mechanical properties, and the in vitro degradation characteristic of a composite membrane made of poly(L, DL-lactide) and alpha-tricalcium phosphate in comparison to a membrane made of pure poly(L, DL-lactide). The tensile strength and the elastic modulus as well as the molecular weight of the membranes were measured after in vitro degradation in buffer at 37 degrees C up to 28 weeks. The initial tensile strength of the composite and the polymer membrane was 37.3 +/- 2.4 MPa and 27.7 +/- 2.3 MPa and the elastic modulus 3106 +/- 108 MPa and 3101 +/- 104 MPa, respectively. The mechanical properties remained constant up to 8 weeks and then decreased slowly until week 28. The molecular weight of both membranes decreased steadily from 170,000 D to 30,000 D. It was concluded that the mechanical requirements for a membrane for GBR were fulfilled by the composite membrane.

[Intra-arterial chemotherapy]. / Intraarterielle Chemotherapie.

BACKGROUND: The development of arterial chemotherapy in the course of the twentieth century is recapitulated, emphasizing the implications of advancements which have been made in anatomic examination and cell biology. CHEMOTHERAPY: The literature is reviewed to determine the current position of arterial chemotherapy among other treatment strategies. As a single modality treatment, it is exclusively employed as palliative treatment. Combined with surgery, radiation or immune therapy, arterial chemotherapy is of further significance as part of multimodality treatment. The best chance for cure is achieved if applied as induction therapy.

Intra-arterial preoperative cytostatic treatment versus preoperative irradiation: A prospective, randomized study of lingual and sublingual carcinomas.

BACKGROUND: For several decades, both preoperative intra-arterial chemotherapy and preoperative irradiation have been accepted treatments for patients with tumors of the head and neck. Unfortunately, arguments have often been put forward in favor of one or other of the two methods, but without the performance of an objective, randomized investigation. To resolve this situation, the authors have carried out a multicenter, randomized prospective study of selected patients with a view to deciding which method affords better results in complex tumor therapy from the aspects of survival and postoperative quality of life. METHODS: One hundred thirty-one patients with operable sublingual or lingual squamous cell carcinoma in stages T2NXM0 to T4MXM0 were randomized into 2 groups: 1 group participated in preoperative chemotherapy with cisplatin and epirubicin (total doses: 200 mg cisplatin, 120 mg epirubicin) via the external carotid artery, whereas the other group received preoperative radiation therapy (46 grays). Following subsequent radical surgery, the patients received regular follow-up for 5 years. RESULTS: By the end of the 5 years, 95 of the 131 patients had conformed to the protocol. Of those 95, 47 had received preoperative chemotherapy and 48 preoperative irradiation. After 5 years, 18 of the 47 patients who received chemotherapy and 15 of the 48 patients who received irradiation were still alive and tumor free. A few more patients had died of recurrence or regional metastasis in the chemotherapy group (23 patients) than in the irradiation group (20 patients). Occurrence of a second carcinoma was 3 times as frequent in the irradiation group (9 patients) as in the chemotherapy group (3 patients). Overall, the survival rates were by-and-large the same for the two groups. Regarding postoperative quality of life, the chemotherapy group presented a more favorable picture. CONCLUSIONS: The long term survival results subsequent to preoperative intra-arterial chemotherapy or preoperative radiotherapy were practically the same. Regarding postoperative quality of life, patients who underwent intra-arterial chemotherapy appeared to be in a slightly more favorable situation. The authors consider it important to stress these findings, as they are not aware of a similar randomized study of patients with tumors of the oral cavity.

The influence of the spring activator on the mobility of the lower jaw in traumatically injured patients.

For functional rehabilitation and improvement of mandibular mobility, 14 patients with dislocated collum or collum fracture dislocations were treated with a spring activator after surgical-conservative treatment. With an interincisal distance of < 12 mm, therapy was started with a loop spring. The average age of the patients was 26.6 years. Eight patients showed additional traumatic injuries, 2 patients were seriously polytraumatically injured. The clinical investigations referring to the maximum mouth opening and maximal interincisal distance resulted in a good to very good functional rehabilitation in all cases. The average maximal interincisal distance of 31.7 mm at the beginning of the spring activator therapy could be increased to 47.3 mm. The largest increase of the maximal interincisal distance was observed after 4 weeks of therapy. The type of reaction, however, differed interindividually. Three patients showed a spontaneous improvement of the interincisal distance within the first 2 to 3 weeks of removal of intermaxillary fixation, whereas 7 patients showed no improvement or only slightly improved values until insertion of the spring activator. An enlargement of the interincisal distance could be achieved in almost every patient within a relatively short period of time despite a drastically reduced mouth opening. Consequently, because of its mode of action in the form of a neuromuscular influence, the spring activator is especially suitable for the functional rehabilitation of patients with fractures of the condylar process.

The significance of DNA flow cytometry in predicting survival and delayed clinical manifestation of occult lymph node metastasis to the untreated neck in patients with oral squamous cell carcinoma.

A total number of 116 clinically neck-negative patients with squamous cell carcinoma of the oral cavity who underwent radical primary tumour surgery without simultaneous neck treatment were entered into this prospective study. The 5 year overall survival rate was 87% for patients with flow cytometrically diploid tumours and 58% for the aneuploid group (P < 0.05). By multivariate survival analysis, tumour stage (P < 0.05) and DNA ploidy (P < 0.05) were significantly associated with the outcome. The cumulative 3 year rate of delayed clinical manifestation of lymph node metastasis to the previously untreated neck was 12.6% for patients with flow cytometrically diploid tumours and 41.3% for the aneuploid group (P < 0.01). By multivariate analysis, the DNA ploidy status of the primary tumour was the only factor among tumour stage, localization and degree of histological differentiation predictive of occult metastasis development (P < 0.05). Also, patients with T1 tumours who frequently are not considered to benefit from elective neck dissection were at high risk of subclinical lymph node involvement if the primary tumours were aneuploid (47%), whereas only 10% of the diploid T1 sample showed occult neck disease. Particularly in patients with less extensive oral carcinomas, DNA aneuploidy is therefore an important decisive factor in elective neck dissection.

Morphology and blood supply of the iliac crest applied to jaw reconstruction.

The aim of this study was to improve vessel and nerve security and the harvesting procedure of the iliac crest in the microvascular reconstruction of the upper and lower jaw by iliac crest flap in cases of tumour invasion or trauma. The critical points for the surgeon in harvesting the iliac crest are the course of the deep circumflex iliac artery and lateral cutaneous nerve of the thigh in relation to the iliac crest and the position of their subsequent ramifications. Bilateral anatomical preparations of the iliac bone (total 90 dissections) were examined in 45 formalin preserved cadavers (21 male, 24 female) with the course of the vessel and nerve supply being mapped. Topographic variations of muscles, bones, vessels and nerves were documented by measurement by photographic documentation and diagrams. In 78% (70 cases) a standard-type arrangement with a single main vessel coming from the external iliac artery above the inguinal ligament and crossing the upper part of the iliac crest with second ramifications was observed. In 12% (11 cases) the main vessel was observed to be 2-3 cm below the iliac crest, in 7% (6 cases) a second main branch of the deep circumflex iliac artery was found to run parallel to the iliac crest. In other cases the following variations were observed: one main vessel without ramification, separate branching of the main vessel and ramifications or common trunks of the deep and superficial circumflex iliac arteries. Because of these results it might be possible to perform window resection of the iliac crest in some cases rather than bloc resection: this may have postoperative advantages for the patient.

Flow cytometric DNA ploidy and recurrence development in squamous cell carcinoma of the oral cavity.

This prospective study on 348 patients with oral squamous cell carcinoma who underwent radical surgery established a close association between the DNA ploidy status of the primary tumor and the risk of local recurrence development. Nine percent of patients with flow cytometrically diploid tumors developed a recurrence compared to 46% of those with aneuploid tumors. This correlation held true even if evaluated with respect to tumor stage or histological grade. Thirteen percent of the diploid and 59% of the aneuploid group showed lymph node metastasis. These results provide substantial evidence that cytogenetic events that underlie aneuploidy formation from initially diploid progenitor cells are functionally linked to the development of tumor cell populations that have the capability to establish independently growing colonies in foreign tissues.

Flow cytometric cellular DNA content and lymph-node metastasis in squamous-cell carcinoma of the oral cavity.

This prospective DNA flow cytometric study on 386 primary squamous cell carcinomas of the oral cavity showed that only 18% of the patients with diploid primary tumors had lymph node metastasis on admission compared to 52% of those with aneuploid carcinomas. The aneuploid group without evidence of lymph node involvement at the time of primary tumor treatment carried a 3-fold increased risk for developing late metastasis (23%) compared with the diploid group (8%). The clinical manifestation of occult metastasis in patients with diploid carcinomas was delayed by about two years compared to the aneuploid group. These ploidy-specific differences of the metastatic behaviour held true even if stratified with respect to tumor stage, histological grade and tumor localization. These results provide substantial evidence that cells with gross DNA content aberrations have a significantly higher probability of successfully producing a metastatic colony than flow cytometrically diploid tumor cells. An excellent 5-year survival rate of 90% in the diploid NO group in contrast to 52% in aneuploid NO cases and an even worse survival rate of 21% in patients with lymph node involvement at presentation underline the clinical importance of these findings.

Monitoring of anticancer drug effects in vivo by serial DNA flow cytometry of oral carcinomas treated by intra-arterial 5-fluorouracil/cisplatin induction chemotherapy.

Thirty-one patients with squamous cell carcinomas of the oral cavity who underwent intra-arterial induction chemotherapy with 5-fluorouracil and cisplatin were analysed by DNA flow cytometry. Seven tumors consisted exclusively of diploid cells and 24 were characterized by the presence of an aneuploid tumor cell line. Response to chemotherapy as well as survival were significantly better in the diploid group. The cytotoxic effect of the treatment on aneuploid tumor cell populations was monitored in vivo by serial DNA flow cytometric measurements. Decreasing numbers of aneuploid cells were detected in all but two cases (92%); twelve (50%) showed a complete disappearance of the aberrant cell line at the end of chemotherapy. All non-responders showed persisting aneuploid tumor cells at the end of treatment. Even if response to chemotherapy was better in the group with a complete disappearance of the aneuploid cell line in the course of treatment, the survival outcome of these patients did not differ significantly from those who showed persistence of aneuploid tumor cells.

A retrospective analysis of 367 cystic lesions of the jaw--the Ulm experience.

Out of 846 cyst-like lesions of the jaws, 367 cases were retrieved from the files of the Department of Oral and Maxillofacial Surgery at the University of Ulm and classified according to the new World Health Organization's classification for odontogenic tumours and cysts. Radicular and residual cysts comprised 56.9%, dentigerous cysts 21.3%, odontogenic keratocysts 10.6%, unicystic ameloblastomas 4.1%, nasopalatine duct cysts 2.7%, glandular odontogenic cysts 1.6% and paradental cysts, traumatic bone cysts, calcifying odontogenic cyst and lateral periodontal cyst each less than 1% of the sample. Nearly one third of the specimens were obtained from military patients; despite an expected bias towards young males, unicystic ameloblastomas presented one and a half decades later than is generally reported.

Comparison of flow cytometric DNA content in the primary tumor and in the corresponding lymph-node metastasis of patients with squamous cells carcinomas of the head and neck.

The clonal DNA content of the cell populations of primary tumors and corresponding lymph node metastases was analysed by DNA flow cytometry in 48 patients with squamous cell carcinoma of the oral cavity. Three primary tumors were diploid, two associated with diploid metastases, one showing an aneuploid cell line in the secondary lesion. Fourty-five cases were aneuploid in both the primary tumors and in the synchronous metastases, all characterized by nearly identical DNA indices of the corresponding primary and secondary lesions. With few exceptions, aneuploidy formation appears to take place prior to dissemination of metastatic cells.

[Cytostatic-induced stomatitis]. / Zytostatika-induzierte Stomatitis.

45 patients with oral cancer preoperatively received regional intraarterial chemotherapy (RIAC). All patients developed stomatitis or glossitis limited to the region of cytostatic perfusion. Between 1 and 19 days (median 4 days) after RIAC the tumor was removed by hemiglossectomy, partial resection of the floor of the mouth etc. The tissue alterations induced by chemotherapy in these surgical specimens were analyzed histomorphologically. Stomatitis due to RIAC was characterized by necrosis, ulceration and severe epithelial dysplasia of mucous membranes. Approximately 2 weeks after chemotherapy both the inflammatory changes and the dysplasia had disappeared completely. The differences between spontaneous premalignant dysplasia of the oral cavity and dysplasia induced by RIAC are discussed.

[CT structural analysis of the ramus]. / Computertomographische Strukturanalyse des Ramus ascendens mandibulae.

Size and quality of the medullary space in the mandibular ramus are highly variable. Mean value studies using CT scans show a broad range of variation for vertical measurements of the medullary space. An individual CT scan of the mandibular ramus therefore seems to be necessary to establish the optimum line of osteotomy in preparing a sagittal split osteotomy of the mandible.

[The DNA ploidy in squamous cell carcinomas of the mouth floor determined by flow cytometry]. / DNA-Ploidie bei Plattenepithelkarzinomen des Mundbodens bestimmt mit Hilfe der Durchflusszytophotometrie.

The cellular DNA content of 90 primary squamous cell carcinomas of the floor of mouth was determined by flow cytometry. Aneuploid cell lines were detected in 86% of the cases. The proportion of diploid carcinomas decreased with size (T1: 63%, T2: 11%, T3: 7%) and histologic grade (G1: 17%, G2: 16%, G3: 9%). Only 15% of the diploid, but 61% of the aneuploid tumors showed evidence of lymph node involvement. A 96% sensitivity of the test and a negative predictive value of 85% emphasize the prognostic importance of DNA ploidy in the primary tumor to evaluate the risk of subclinical dissemination.

Monitoring of intra-arterial treatment with epirubicin and cisplatin in oral carcinoma by DNA flow cytometry.

Twenty-two patients with squamous cell carcinoma of the oral cavity were treated intra-arterially with epirubicin and cisplatin. Biopsies were taken before, during, and after treatment and analysed by DNA flow cytometry. Clinical response to therapy was better in the diploid group as well as in previously aneuploid tumors which showed complete disappearance of the abnormal clone in the course of treatment. Poor reduction of tumor volume corresponded with persistence of aneuploid cells.

Flow cytometric DNA ploidy analysis of squamous cell carcinoma of the oral cavity. Comparison with clinical staging and histologic grading.

The clonal DNA content of tumor biopsy specimens of 110 patients with primary and untreated squamous cell carcinoma of the oral cavity was determined by flow cytometric study. The ploidy status was compared with tumor size and histologic grading. Thirty tumors (27.3%) were diploid; in 80 cases (72.7%) cell lines with abnormal DNA content were detected. The portion of aneuploid tumors increased with decreasing degree of histologic differentiation (P less than 0.001) from G1 (38.1%) to G2 (76.6%) and G3 (92.0%). Only one of 13 T1 carcinomas (7.6%) showed abnormal clonal DNA content, but 76.9% of T2 and 90.6% T3 tumors (P less than 0.001) did. The emergence of aneuploid clones obviously represents a marker of malignancy progression in oral carcinoma.

The orthopan tomoscintigram--a new application of emission computed tomography for facial bone scanning.

The exact regional correlation of findings of facial bone scans, planar or SPECT, to dental orthopan X-ray films (OPT) is difficult because of the very different projection techniques. To improve correlative imaging in this regard a projection algorithm was developed that uses SPECT data of the skull for reconstructing an orthopan tomoscintigraphic projection. Fourteen conventional SPECT slices of the upper and lower jaws were obtained during bone scanning. All mandibular slices were superimposed resulting in a horseshoe shaped structure, while was marked by an ROI which was divided into segments. All 14 SPECT slices were then masked by this segmental ROI, thereby marking the teeth-carrying bone in all slices. The information from this horseshoe like ROI is then transformed into lines. Line by line arrangement results in an orthopan projection, the orthopan tomoscintigram. This new display allows 1:1 true scale superimposition with the X-ray OPT and markedly facilitates correlative imaging.