CAD/CAM and conventional reconstruction of the mandibular condyle by fibula free flap: a clinical and radiological evaluation.

The aim of this study was to analyse the radiological and clinical outcomes of condylar reconstruction by fibula free flap (FFF), comparing conventional freehand and CAD/CAM techniques. Fifteen patients (nine CAD/CAM, six freehand) who underwent condylar reconstruction with a FFF were reviewed retrospectively regarding pre- and postoperative computed tomography/cone beam computed tomography scans and clinical function. After surgery, all patients were free of temporomandibular joint pain. Mean postoperative mouth opening was 30.80 mm, with no significant difference between the freehand and CAD/CAM groups. In all patients, laterotrusion was decreased to the contralateral side (P = 0.002), with no difference between freehand and CAD/CAM, while the axis of mouth opening deviated to the side of surgery (P < 0.001). All patients showed significant radiological deviation of the fibular neocondyle in the laterocaudal direction (lateral: P = 0.015; caudal: P = 0.001), independent of the technique. In conclusion, reconstruction of the mandibular condyle by FFF provided favourable functional results in terms of mouth opening, reduction of pain, and mandibular excursions. Radiological deviation of the neocondyle and deviation of laterotrusion and mouth opening did not impair clinical function. CAD/CAM planning facilitated surgery, decreased the surgery time, and improved the fit of the neocondyle in the fossa.

Alternatives to free flap surgery for maxillofacial reconstruction: focus on the submental island flap and the pectoralis major myocutaneous flap.

BACKGROUND: Microvascular tissue transfer (MTT) has been established as the gold standard in oral- and maxillofacial reconstruction. However, free flap surgery may be critical in multimorbid elderly patients and after surgery or radiotherapy, which aggravate microsurgery. This study evaluates indications and outcome of the submental island flap (SMIF) and the pectoralis major myocutaneous flap (PMMF) as alternatives to the free radial forearm flap (RFF). METHODS: This retrospective study included 134 patients who had undergone resection and reconstruction with SMIF, PMMF, or RFF at our department between 2005 and 2020. The level of comorbidity was measured with the Age-adjusted Charlson comorbidity index (ACCI). Primary outcome variables were flap success, complications, wound dehiscence, surgery duration, as well as time at the ICU and the ward (hospitalization). Chi-square tests, t-tests, and ANOVA were performed for statistics. RESULTS: 24 SMIFs, 52 RFFs, and 58 PMMFs were included in this study. The flap types did not significantly differ in terms of flap success, complications, and healing disorders. The SMIF presented a success rate of 95.8% and was significantly more often used in elderly patients (mean age = 70.2 years; p < 0.001) with increased comorbidities than the PMMF (p < 0.01) and RFF (p < 0.001). SMIF reconstruction reduced surgery duration (p < 0.001) and time at the ICU (p = 0.009) and the ward (p < 0.001) more than PMMF and RFF reconstructions. PMMF reconstruction was successful in 91.4% of patients and was more frequently used after head and neck surgery (p < 0.001) and radiotherapy (p < 0.001) than SMIF and RFF reconstructions. Patients undergoing PMMF reconstruction more frequently required segmental jaw resection and had presented with advanced tumor stages (both p < 0.001). Nicotine and alcohol abuse was more frequent in the RFF and PMMF groups (both p < 0.001) than in the SMIF group. CONCLUSIONS: The pedicled SMIF represents a valuable reconstructive option for elderly patients with increased comorbidity because of the shorter duration of surgery and hospitalization. On the other hand, the PMMF serves as a solid backup solution after head and neck surgery or radiotherapy. The rates of flap success, complications, and healing disorders of both pedicled flaps are comparable to those of free flap reconstruction.

Differential localization of PD-L1 and Akt-1 involvement in radioresistant and radiosensitive cell lines of head and neck squamous cell carcinoma.

Immunotherapy by blockade of the PD-1/PD-L1 checkpoint demonstrated amazing tumor response in advanced cancer patients including head and neck squamous cell carcinoma (HNSCC). However, the majority of HNSCC patients still show little improvement or even hyperprogression. Irradiation is currently investigated as synergistic treatment modality to immunotherapy as it increases the number of T-cells thereby enhancing efficacy of immunotherapy. Apart from this immunogenic context a growing amount of data indicates that PD-L1 also plays an intrinsic role in cancer cells by regulating different cellular functions like cell proliferation or migration. Here, we demonstrate opposing membrane localization of PD-L1 in vital and apoptotic cell populations of radioresistant (RR) and radiosensitive (RS) HNSCC cell lines up to 72 h after irradiation using flow cytometry. Moreover, strong PD-L1 expression was found in nuclear and cytoplasmic cell fractions of RR. After irradiation PD-L1 decreased in nuclear fractions and increased in cytoplasmic fractions of RR cells. In contrast, RS cell lines did not express PD-L1, neither in the nucleus nor in cytoplasmic fractions. Additionally, overexpression of PD-L1 in RS cells led to a proportional increase of vital PD-L1 positive cells after irradiation. Moreover, co-immunoprecipitation experiments revealed an interaction between Akt-1 and PD-L1, mostly in irradiated RR cells compared to RS cells suggesting a differential influence of PD-L1 on cell signaling. In summary, our data imply the need for different therapeutic strategies dependent on the molecular context in which PD-L1 is embedded.

Magnetic resonance angiography for free fibula harvest: anatomy and perforator mapping.

The purpose of this study was to outline lower leg vessel anatomy and to investigate reliability and limitations of magnetic resonance angiography (MRA) in patients proposed for microvascular fibula transplantation (free fibula flap (FFF)). We retrospectively investigated MRAs of 99 patients considered for FFF. Frontal MRA planes and maximal intensity projections (MIPs) were evaluated for fibula lengths, anatomical branching pattern, arterial stenoses and fibular perforator positions in both legs (n=198). Normal branching patterns were observed in 168 (85.3%) legs. Twenty-nine (14.7%) legs presented abnormal branching patterns. Once (0.5%) the anterior, 19 times (9.6%) the posterior tibial artery were absent or hypoplastic. Nine (4.6%) lower legs presented an arteria peronea magna. Average length of the tibiofibular trunk (TFT) was 3.3±0.15cm. A total of 492 perforators were found with an average of 2.5 (±0.82±0.99) perforators per leg. A mapping of perforator run-offs was illustrated true to scale. Lower limb stenoses were distributed in the anterior tibial artery (14.1%), in the posterior tibial artery (11.1%) and in the fibular artery (8.1%). Smoking (P=0.828), diabetes (P=0.727) and peripheral arterial occlusive disease (P=0.172) did not correlate with presence of stenoses. Preoperative lower limb angiography avoids postoperative complications. MRA reliably and non-invasively identifies anatomical variants and arterial stenoses without radiation. Illustration of perforator run-offs enhances incision planning for fibula harvest.

Health-related quality of life: a retrospective study on local vs. microvascular reconstruction in patients with oral cancer.

BACKGROUND: New medicinal and surgical oncological treatment strategies not only improve overall survival rates but continually increase the importance of Health-Related Quality of Life (HRQOL). The purpose of this retrospective cross-sectional study was to analyze HRQOL of patients with oral squamous cell carcinoma after ablative surgery and to evaluate predictive factors for HRQOL outcome. METHODS: The study included 88 patients with histologically confirmed oral squamous cell carcinoma of whom 42 had undergone local reconstruction (LR) and 46 microvascular reconstruction (MVR). During follow-up, all patients completed the University of Washington Quality of Life Questionnaire (UW-QOL) containing 12 targeted questions about the head and neck. Descriptive analyses were made for the tumor site, the T-stage, and adjuvant therapies. HRQOL was compared between the LR and the MVR group with parametric tests. Further analyses were impact of the tumor site, the T-status, and the time from surgery to survey on HRQOL. Statistics also included multivariate correlations and different interaction effects. RESULTS: HRQOL in the LR group was 'very good' with 84.3 ± 13.7 and 'good' in the MVR group with 73.3 ± 16.5 points. The physical domains swallowing (p = 0.00), chewing (p = 0.00), speech (p = 0.01), taste (p = 0.01), and pain (p = 0.04) were significantly worse in the MVR group. An increase in the T-status had a significant negative effect on swallowing (p = 0.01), chewing (p = 0.01), speech (p = 0.03), recreation (p = 0.05), and shoulder (p = 0.01) in both groups. Regarding the tumor site and subsequent loss of HRQOL, patients with squamous cell carcinoma on the floor of the mouth had significantly worse results in the categories pain (p = 0.002), speech (p = 0.002), swallowing (p = 0.03), activity (p = 0.02), and recreation (p = 0.01) than patients with tumors in the buccal mucosa. Speech (p = 0.03) and pain (p = 0.01) had improved 1 year after surgery. CONCLUSION: Patients with flap reconstruction because of oral squamous cell carcinoma showed very good overall HRQOL. Outcomes for microvascular reconstruction were good, even in the case of larger defects. The T-status is a predictor for HRQOL. Swallowing, chewing, speaking, taste, and pain were the most important issues in our cohort. Implementing HRQOL questionnaires for the assessment of quality of life could further increase the treatment quality of patients with oral cancer.

The parathyroid hormone-related protein is secreted during the osteogenic differentiation of human dental follicle cells and inhibits the alkaline phosphatase activity and the expression of DLX3.

The dental follicle is involved in tooth eruption and it expresses a great amount of the parathyroid hormone-related protein (PTHrP). PTHrP as an extracellular protein is required for a multitude of different regulations of enchondral bone development and differentiation of bone precursor cells and of the development of craniofacial tissues. The dental follicle contains also precursor cells (DFCs) of the periodontium. Isolated DFCs differentiate into periodontal ligament cells, alveolar osteoblast and cementoblasts. However, the role of PTHrP during the human periodontal development remains elusive. Our study evaluated the influence of PTHrP on the osteogenic differentiation of DFCs under in vitro conditions for the first time. The PTHrP protein was highly secreted after 4days of the induction of the osteogenic differentiation of DFCs with dexamethasone (2160.5pg/ml±345.7SD. in osteogenic differentiation medium vs. 315.7pg/ml±156.2SD. in standard cell culture medium; Student's t Test: p<0.05 (n=3)). We showed that the supplementation of the osteogenic differentiation medium with PTHrP inhibited the alkaline phosphatase activity and the expression of the transcription factor DLX3, but the depletion of PTHrP did not support the differentiation of DFCs. Previous studies have shown that Indian Hedgehog (IHH) induces PTHrP and that PTHrP, in turn, inhibits IHH via a negative feedback loop. We showed that SUFU (Suppressor Of Fused Homolog) was not regulated during the osteogenic differentiation in DFCs. So, neither the hedgehog signaling pathway induced PTHrP nor PTHrP suppressed the hedgehog signaling pathway during the osteogenic differentiation in DFCs. In conclusion, our results suggest that PTHrP regulates independently of the hedgehog signaling pathway the osteogenic differentiated in DFCs.

The influence of third molars in the line of mandibular angle fractures on wound and bone healing.

OBJECTIVES: The objective of this study was to evaluate postoperative complications after removal or retention of the third molar in the line of mandibular angle fractures. MATERIALS AND METHODS: This retrospective study included the data of 98 patients with a molar in the line of a mandibular angle fracture treated with internal reduction and mini-plate fixation at our department over 9 years. Patients were classified into two groups: tooth removal during osteosynthesis (n = 45) and tooth retention (n = 55). The primary target criterion was the incidence of minor (outpatient treatment, local measures) and major (surgical revision, rehospitalisation) complications. Time between trauma and surgery was 1.4 days (range 0 to 12), and the average follow-up 291 days (range 66 to 863). RESULTS: Regarding the eruption status, 26 of 52 (50.0 %) impacted third molars, 11 of 19 (57.9 %) incompletely erupted and 8 of 27 (29.6 %) completely erupted molars had been removed during open reduction. Overall, 17 (17.3 %) patients had postoperative minor (n = 7) or major (n = 10) complications, in detail 10/45 (22.0 %) patients after tooth removal and 7/55 (13 %) patients after tooth retention (p = 0.286). Complication rates between impacted and incompletely erupted third molars (impacted molars 15.0 %, incompletely erupted molars 10.0 %) did not differ significantly, but completely erupted molars had a complication rate of 26.0 %. CONCLUSIONS: Mandibular angle fractures with a completely erupted third molar show the highest complication rate after open reduction and osteosynthesis. Retention of a non-infectious third molar facilitates open reduction and does not increase the complication risk. CLINICAL RELEVANCE: The study helps with the decision of removing or retention of a third molar during surgical treatment of a mandibular angle fracture.

The AKT signaling pathway sustains the osteogenic differentiation in human dental follicle cells.

Signaling transduction pathways are established by interactions between growth factors, protein kinases, and transcription factors, and they play a crucial role in tooth development. Precursor cells of the dental follicle (DFCs) are used for in vitro studies about molecular mechanisms during periodontal development. Previous studies have already shown that the growth factor BMP2 and the transcription factor EGR1 are involved in the osteogenic differentiation in DFCs while interactions with protein kinase-based pathways remain elusive. In this current study, we investigated the role of the AKT kinase signaling pathway for the osteogenic differentiation in DFCs. The AKT signaling pathway was activated in DFCs after the induction of the osteogenic differentiation by BMP2. The inhibition of AKT in DFCs repressed the differentiation and the expression of the transcription factor EGR1. Interestingly, EGR1 bound to the phosphorylated form of SMAD1/5 (pSMAD). The binding of pSMAD to EGR1 was increased after the induction with BMP2. Moreover, the overexpression EGR1 increased the osteogenic differentiation of DFCs. Our results suggest that the AKT signaling pathway submits the BMP2-dependent osteogenic differentiation in DFCs via the expression of the transcription factor EGR1.

The WNT inhibitor APCDD1 sustains the expression of ß-catenin during the osteogenic differentiation of human dental follicle cells.

In hair follicle cells APCDD1 inhibits the canonical WNT/ß-Catenin pathway and its inactivation is associated with an autosomal dominant form of hair loss. We analyzed the role of APCDD1 for the osteogenic differentiation in dental follicle cells (DFCs) and identified a new and surprising function. Contrarily to hair follicle cells APCDD1 was crucial for the expression of ß-Catenin and for the activity of the TCF/LEF reporter assay in DFCs. In addition, a depletion of APCDD1 inhibits the expression of osteogenic markers such as RUNX2 and decreased the matrix mineralization. However, similar to hair follicle cells in previous studies a control cell culture with oral squamous carcinoma cells showed that APCDD1 inhibits the expression of ß-Catenin and of typical target genes of the canonical WNT/ß-Catenin pathway. In conclusion, our data disclosed an unusual role of APCDD1 in DFCs during the osteogenic differentiation. APCDD1 sustains the expression and activation of ß-Catenin.

A protein kinase A (PKA)/ß-catenin pathway sustains the BMP2/DLX3-induced osteogenic differentiation in dental follicle cells (DFCs).

The directed expression of osteogenic transcription factors via a balanced activation of signaling pathways is an important prerequisite for the development of mineralized tissues. A positive-feedback loop of the BMP2-dependent SMAD signaling pathway and the DLX3 transcription factor (BMP2/DLX3 pathway) directs the osteogenic differentiation of periodontal precursor cells from the dental follicle (DFCs). However, little is known how this BMP2/DLX3 pathway interacts with other crucial signaling pathways such as the WNT/ß-catenin signaling pathway. This study investigated the interaction between the BMP2/DLX3 pathway and the WNT pathway during the osteogenic differentiation of DFCs. BMP2 induced the WNT/ß-catenin pathway in DFCs and phosphorylates ß-catenin via protein kinase A (PKA). Moreover, only BMP2 facilitated the binding of LEF1/SMAD4/ß-catenin complex to the DLX3 promoter, while an inducer of the canonical WNT pathway, WNT3A, act as an inhibitor. Although WNT3A inhibits the osteogenic differentiation of DFCs the expression of ß-catenin was crucial for both the expression of DLX3 and for the osteogenic differentiation. In conclusion, while the activation of the canonical WNT pathway inhibits the osteogenic differentiation of DFCs, ß-catenin sustains the BMP2/DLX3-mediated osteogenic differentiation via the activation of PKA.

Loss of PTEN is associated with elevated EGFR and HER2 expression and worse prognosis in salivary gland cancer.

BACKGROUND: Activity of the tumour-suppressor gene PTEN is reduced in different types of cancer and implicates non-responsiveness to targeted therapy. This study evaluates the gene and protein status of PTEN in salivary gland carcinomas. METHODS: A total of 287 carcinomas of the major and minor salivary glands were investigated for phosphatase and tensin homologue located on chromosome 10 (PTEN) deletion and loss of PTEN expression using fluorescence in situ hybridisation (FISH) and immunohistochemistry (IHC), respectively. Results were correlated to clinicopathological parameters, long-term survival, epidermal growth factor receptor (EGFR) and human epidermal growth factor receptor 2 (HER2) (IHC and FISH) status of the tumours. RESULTS: Hemizygous deletions of PTEN were found in 35 out of 232 (15.1%) carcinomas, while homozygous deletions were observed in 17 out of 232 (7.3%) tumours. Phosphatase and tensin homologue located on chromosome 10 deletion was common in certain histological subtypes and especially homozygous deletion was associated with high-grade malignancy, lymph node metastases and unfavourable long-term prognosis (P<0.001). Loss of PTEN expression was present in 59 out of 273 (21.6%) carcinomas and was significantly correlated to genomic PTEN deletion, high-grade malignancy (P<0.001), increased tumour size (P=0.036), lymph node metastases (P=0.007) and worse disease-specific survival (P=0.002). Genomic PTEN deletion, in particular homogenous deletion (P<0.001) predominantly occurred in tumours with increased gene copy number of EGFR (60.0%) and/or amplification of HER2 (63.6%). Loss of PTEN expression was frequently found in tumours overexpressing EGFR (28.6%) and/or HER2 (52.6%). CONCLUSION: PTEN function is reduced in different types of salivary gland cancer indicating unfavourable prognosis. Its association with EGFR and HER2 signalling might affect targeted therapy.

Cancer stem cell-like cells from a single cell of oral squamous carcinoma cell lines.

Resistance of oral squamous cell carcinomas (OSCC) to conventional chemotherapy or radiation therapy might be due to cancer stem cells (CSCs). The development of novel anticancer drugs requires a simple method for the enrichment of CSCs. CSCs can be enriched from OSCC cell lines, for example, after cultivation in serum-free cell culture medium (SFM). In our study, we analyzed four OSCC cell lines for the presence of CSCs. CSC-like cells could not be enriched with SFM. However, cell lines obtained from holoclone colonies showed CSC-like properties such as a reduced rate of cell proliferation and a reduced sensitivity to Paclitaxel in comparison to cells from the parental lineage. Moreover, these cell lines differentially expressed the CSC-marker CD133, which is also upregulated in OSCC tissues. Interestingly, CD133(+) cells in OSCC tissues expressed little to no Ki67, the cell proliferation marker that also indicates reduced drug sensitivity. Our study shows a method for the isolation of CSC-like cell lines from OSCC cell lines. These CSC-like cell lines could be new targets for the development of anticancer drugs under in vitro conditions.

Recurrent aneurysmal bone cyst of the mandibular condyle with soft tissue extension.

The case of a 17- year-old female patient with a destructive aneurysmal bone cyst of the right mandibular condyle is presented. Surgery revealed an eggshell thin, partly perforated remaining condylar cortex with extension of the lesion into the surrounding soft tissues. Condylar resection with curettage of the adjacent soft tissues and recurrence prophylaxis with intranasal calcitonin for 1 week could not prevent recurrence after 6 months. In a second operation the ascending mandibular ramus was partly resected and immediately reconstructed with a newly developed alloplastic condylar head add-on system. This time the lesion was intraoperatively completely surrounded by solid cortical bone.

Overexpression of EGFR and absence of C-KIT expression correlate with poor prognosis in salivary gland carcinomas.

AIMS: To evaluate the prognostic impact of expression of receptor tyrosine kinases epidermal growth factor receptor (EGFR), HER2, and C-KIT in relation to established clinicopathological parameters in salivary gland carcinomas. METHODS AND RESULTS: Immunohistochemistry for EGFR, HER2, C-KIT and the proliferation marker Ki67 was performed in 101 cases of salivary gland carcinoma and related to long-term clinical follow-up. Immunopositivity of C-KIT was common in adenoid cystic carcinoma (92%). Lack of C-KIT expression occurred in salivary duct carcinoma (P < 0.001) and was associated with high-grade tumours (P = 0.002), positive lymph nodes (P = 0.002) and high expression of Ki67 (P = 0.001). HER2 was typically expressed in salivary duct carcinomas (83%), but was not associated with any other parameter. EGFR overexpression occurred independently of histological type and clinical parameters. On univariate survival analysis, overexpression of EGFR (P = 0.011) and lack of C-KIT (P = 0.014) were associated with worse prognosis, whereas HER2 was of no prognostic significance. On multivariate analysis, the strongest negative predictor of survival was high proliferative activity measured by Ki67 (P = 0.002), followed by presence of residual tumour (P = 0.006), overexpression of EGFR (P = 0.026) and advanced tumour stage (P = 0.041). CONCLUSIONS: The expression of receptor tyrosine kinases confers additional prognostic impact on disease-specific survival. EGFR overexpression is an independent negative prognostic factor.

[Prognostic value of immunohistochemistry in salivary gland cancer]. / Immunhistochemie als Prognoseindikator bei Speicheldrüsenkarzinomen.

BACKGROUND: The diversity of salivary gland malignancies as to morphology and clinical course makes it difficult to establish prognostic factors. The aim of this study was to evaluate the prognostic significance of, a. o., immunohistochemical criteria in a retrospective study of salivary gland cancer. PATIENTS AND METHODS: Clinical and histologic data were recorded for 101 patients with carcinomas of the salivary glands. Immunohistochemistry was performed for Ki-67, P53, C-KIT, HER2, EGFR, and maspin. Correlations to disease-specific long-term survival (mean follow-up 4.7 years) were followed by univariate and multivariate analysis. RESULTS: Findings included the following: an association between loss of maspin and the presence of nodal metastasis, residual tumour, and poor overall survival for adenoid cystic carcinoma; common C-KIT expression in adenoid cystic carcinoma (92%); correlation of loss of C-KIT with high malignancy grade, nodal metastases, high proliferative activity (Ki-67>30%), and unfavourable survival in all tumours; common HER2 expression (83%) in salivary duct carcinoma but no relation to the total collective's survival. Overexpression of EGFR was associated with poor survival rates. In multivariate analysis, a high proliferation index was the strongest predictive factor, followed by the presence of residual tumour, overexpression of EGFR, and advanced clinical stage. CONCLUSIONS: The clinical stage is of higher prognostic value than histology and grade of malignancy. High proliferative activity (Ki-67>30%) is the strongest negative predictor in salivary gland cancer. Besides well-known clinicopathological factors, current immunohistochemical markers such as maspin, EGFR, and C-KIT can contribute to establish prognosis in salivary gland cancer.

[Foudroyant course of a therapy resistent Wegener's granulomatosis with negative c-ANCA]. / Foudroyanter Verlauf einer therapierefraktären Wegener Granulomatose bei negativen c-ANCA.

BACKGROUND: Wegener's Granulomatosis is a rare systemic disease characterized by the triad of necrotizing granulomas of blood vessels, upper respiratory tract, and kidneys. Diagnosis depends on clinical symptoms (ACR-criteria), detection of serum circulating antineutrophil cytoplasmic antibodies (c-ANCA) and bioptical histopathology. CASE-REPORT: A 34-year-old patient presented with intraoral ulcerating, necrotizing inflammations of the palate and the gingiva. Chest radiograph (nodules, infiltrates), urin analysis (red blood cell casts) being inconspicuous Wegener's granulomatosis was diagnosed by histopathology of an intraoral incisional biopsy. Conventional therapy with corticosteroids and cyclophosphamide relapsed while the disease was taking a progressive course (pulmonary infiltrates, necrotizing vasculitides all over the common integument). The patient died of cardiac decompensation three months after diagnosis. c-ANCAs were not present at any time of disease. CONCLUSIONS: 1. Symptoms of the head and neck are manifest in up to 95% of Wegener's granulomatosis. So knowledge of the disease is important for dentists and oral and maxillofacial surgeons in spite of its low prevalence. 2. c-ANCA-titers do not reflect disease activity. Negative c-ANCAs do not exclude Wegener's granulomatosis. 3. Wegener's granulomatosis can take a progressive, therapy resistent course.