Heterotopic bone formation in the musculus latissimus dorsi of sheep using ß-tricalcium phosphate scaffolds: evaluation of different seeding techniques.

Osseous reconstruction of large bone defects remains a challenge in oral and maxillofacial surgery. In addition to autogenous bone grafts, which despite potential donor-site mobility still represent the gold standard in reconstructive surgery, many studies have investigated less invasive alternatives such as in vitro cultivation techniques. This study compared different types of seeding techniques on pure ß-tricalcium phosphate scaffolds in terms of bone formation and ceramic resorption in vivo. Cylindrical scaffolds loaded with autologous cancellous bone, venous blood, bone marrow aspirate concentrate or extracorporeal in vitro cultivated bone marrow stromal cells were cultured in sheep on a perforator vessel of the musculus latissimus dorsi over a 6-month period. Histological and histomorphometric analyses revealed that scaffolds loaded with cancellous bone were superior at promoting heterotopic bone formation and ceramic degradation, with autogenous bone and bone marrow aspirate concentrate inducing in vivo formation of vital bone tissue. These results confirm that autologous bone constitutes the preferred source of osteoinductive and osteogenic material that can reliably induce heterotopic bone formation in vivo.

Presentation and Evaluation of a Modified Wax-Bite Dental Splint for Surgical Navigation in Craniomaxillofacial Surgery.

PURPOSE: The purpose of the present study was to introduce and evaluate the use of a modified "wax-bite dental splint" for surgical navigation in craniomaxillofacial surgery. MATERIALS AND METHODS: A 2-layer wax bite dental splint was fabricated with an anterior extension, and 8 gutta percha markers were incorporated in each splint for marker-based pair-point registration. To evaluate the accuracy, the occlusal registration of the wax bite dental splint was performed on 10 artificial skulls. Consecutively, all the skulls were scanned using a standardized cone-beam computed tomography scanning protocol with the 2-layer wax bite dental splint in place. Automatic rigid marker-based pair-point registration was performed using the iPlan CMF software, version 3.0 (Brainlab AG, Feldkirchen, Germany) using 8 gutta percha markers incorporated into the wax bite dental splint. Additionally, the registration accuracy of 6 anatomic skeletal landmarks was measured on each skull. RESULTS: The mean registration error for each wax bite dental splint ranged from 0.78 to 1.01 mm. The overall mean registration error for the wax-bite dental splint-based registration was 0.89 ± 0.08 mm. The mean registration error for the 6 anatomic landmarks ranged from 1.23 to 2.3 mm. The overall mean registration error was 1.68 ± 0.28 mm. CONCLUSION: The results of the present study show the potential for a wax-bite dental splint as an alternative rigid registration method for surgical navigation in craniomaxillofacial surgery. Moreover, from a clinical viewpoint, the method is accurate, user-friendly, inexpensive, and not time-consuming.

Aberrant expression of caspase 14 in salivary gland carcinomas.

OBJECTIVES: Caspase 14 is reduced in adenocarcinomas of the stomach and colon. In contrast, breast and lung adenocarcinomas frequently show an overexpression of caspase 14. Salivary gland adenocarcinomas have not been evaluated for potential aberrant caspase 14 expression. MATERIALS AND METHODS: Samples from salivary gland carcinomas (n = 43) were analysed by immunohistochemistry (caspase 14, filaggrin, GATA3 and Ki67) and fluorescence in situ hybridization. RESULTS: Caspase 14 is not expressed in normal salivary glands, while in a subfraction of carcinomas (32%) an aberrant expression was found. Filaggrin could not be detected. Caspase 14 staining was not associated with tumour dedifferentiation, GATA3 expression or amplification of gene locus 19p13. CONCLUSION: In summary, aberrant expression of caspase 14 can be found in a subfraction of salivary gland carcinomas but could not be used as a biomarker for a specific carcinoma subtype of the salivary gland.

Modified technique for rehabilitation of facial paralysis using autogenous fascia lata grafts.

PURPOSE: In this retrospective study we used a modified surgical technique for midface reanimation in patients with facial nerve paralysis. Facial atonicity can cause functional impairment regarding speech articulation, oral competence, breathing, and eyelid closure. Furthermore, esthetic and psychological aspects play an important role in patients' emotional interaction and social integration. The chosen rehabilitative technique should offer support against prolapse of facial structures and remedy of functional disabilities and, thereby, prevention of social stigmatization due to disease-related changes in appearance. MATERIALS AND METHODS: Between 2005 and 2013, fascia lata grafts were used as static support in 15 cases of unilateral facial paralysis. Two fascia lata grafts were subcutaneously inserted in the upper and lower lips crossing the midline and sutured at 4 points, including the unaffected part of the orbicularis oris muscle and modiolus. The slings were suspended against the zygomatic arch with an osteosynthesis plate. RESULTS: The patients perceived surgery results as considerably improving their appearance, speech, and alimentation. In 93.3% of cases, no postoperative complications occurred. The follow-up results (8 months to 8 years) remained stable. CONCLUSIONS: This retrospective study showed the advantages of static facial reanimation in appropriate cases. The bony fixated support of the fascial slings allows an immediate improvement of facial symmetry. Additional attachment points including the unaffected part of the orbicularis oris muscle and the use of 2 independent fascia lata slings allow a more accurate adjustment of suspension forces and an incomplete dynamic reanimation of the mouth corner. With respect to its simplicity and minimal invasiveness, this surgical procedure is associated with low morbidity and rapid improvement of the patient's esthetic appearance.

Efficacy of transcutaneous transseptal orbital decompression in treating acute retrobulbar hemorrhage and a literature review.

Decreasing visual acuity secondary to orbital trauma may be caused by sudden space-occupying or expanding intraorbital lesions, including retrobulbar hemorrhage (RBH), herniation, or swelling. RBH must be diagnosed and treated immediately. This article addresses the efficacy of transcutaneous transseptal orbital decompression in a combination with a systematic review of the literature for a comparison of this method with existing treatment options. For this study the department's database was retrospectively screened for patients with acute RBH who were treated between 2009 and 2011 using the authors' approach. Patients presenting with RBH were classified into RBH classes I to III according to three different clinical and radiological manifestations of acute RBH. The efficacy of transcutaneous transseptal orbital decompression was assessed by postoperative visual acuities. The literature review was performed by using the MEDLINE database. The time period for the study was between 2009 and 2011 during which 10 patients were diagnosed with suspected RBH and 9 were treated with the authors' technique. Visual acuities were reconstituted or maintained in almost 86% of patients who were diagnosed and treated according to the authors approach and who survived initial trauma. It was concluded that transcutaneous transseptal orbital decompression provides an efficient and rapid approach for treating patients with acute RBH. By distinguishing three different manifestations of acute RBH, the authors present a diagnostic tool that may facilitate classification of RBH and determination of treatment options.

Accelerating the early angiogenesis of tissue engineering constructs in vivo by the use of stem cells cultured in matrigel.

In tissue engineering research, generating constructs with an adequate extent of clinical applications remains a major challenge. In this context, rapid blood vessel ingrowth in the transplanted tissue engineering constructs is the key factor for successful incorporation. To accelerate the microvascular development in engineered tissues, we preincubated osteoblast-like cells as well as mesenchymal stem cells or a combination of both cell types in Matrigel-filled PLGA scaffolds before transplantation into the dorsal skinfold chambers of balb/c mice. By the use of preincubated mesenchymal stem cells, a significantly accelerated angiogenesis was achieved. Compared with previous studies that showed a decisive increase of vascularization on day 6 after the implantation, we were able to halve this period and achieve explicitly denser microvascular networks 3 days after transplantation of the tissue engineering constructs. Thereby, the inflammatory host tissue response was acceptable and low, comparable with former investigations. A co-incubation of osteoblast-like cells and stem cells showed no additive effect on the density of the newly formed microvascular network. Preincubation of mesenchymal stem cells in Matrigel is a promising approach to develop rapid microvascular growth into tissue engineering constructs. After the implantation into the host organism, scaffolds comprising stem cells generate microvascular capillary-like structures exceptionally fast. Thereby, transplanted stem cells likely differentiate into vessel-associated cells. For this reason, preincubation of mesenchymal stem cells in nutrient solutions supporting different steps of angiogenesis provides a technique to promote the routine use of tissue engineering in the clinic.

Additive effect of mesenchymal stem cells and VEGF to vascularization of PLGA scaffolds.

Bone marrow derived mesenchymal stem cells (bmMSCs) are widely used for the generation of tissue engineering constructs, since they can differentiate into different cell types occurring in bone tissues. Until now their use for the generation of tissue engineering constructs is limited. All cells inside a tissue engineering construct die within a short period of time after implantation of the construct because vascularization and establishment of connections to the recipient circulatory system is a time consuming process. We therefore compared the influences of bmMSC, VEGF and a combination of both on the early processes of vascularization, utilizing the mice skinfold chamber model and intravital fluorescence microscopy. Tissue engineering constructs based on collagen coated Poly d,l-lactide-co-glycolide (PLGA) scaffolds, were either functionalized by coating with vascular endothelial growth factor (VEGF) or vitalized with bmMSC. PLGA without cells and growth factor was used as the control group. Functionalized and vitalized tissue engineering constructs showed an accelerated growth of microvessels compared to controls. Only marginal differences in vascular growth were detected between VEGF containing and bmMSC containing constructs. Constructs containing VEGF and bmMSC showed a further enhanced microvascular growth at day 14. We conclude that bmMSCs are well suited for bone tissue engineering applications, since they are a valuable source of angiogenic growth factors and are able to differentiate into the tissue specific cell types of interest. The dynamic process of vascularization triggered by growth factor producing cells can be amplified and stabilized with the addition of accessory growth factors, leading to a persisting angiogenesis, but strategies are needed that enhance the resistance of bmMSC to hypoxia and increase survival of these cells until the tissue engineering construct has build up a functional vascular system.

Functional features of cancer stem cells in melanoma cell lines.

BACKGROUND: Recent evidence suggests a subset of cells within a tumor with "stem-like" characteristics. These cells are able to transplant tumors in immunodeficient hosts. Distinct from non-malignant stem cells, cancer stem cells (CSC) show low proliferative rates, high self-renewing capacity, propensity to differentiate into actively proliferating tumor cells, and resistance to chemotherapy or radiation. They are often characterized by elevated expression of stem cell surface markers, in particular CD133, and sets of differentially expressed stem cell-associated genes. CSC are usually rare in clinical specimens and hardly amenable to functional studies and gene expression profiling. In this study, a panel of heterogenous melanoma cell lines was screened for typical CSC features. METHODS: Nine heterogeneous metastatic melanoma cell lines including D10 and WM115 were studied. Cell lines were phenotyped using flow cytometry and clonogenic assays were performed by limiting dilution analysis on magnetically sorted cells. Spheroidal growth was investigated in pretreated flasks. Gene expression profiles were assessed by using real-time rt-PCR and DNA microarrays. Magnetically sorted tumor cells were subcutaneously injected into the flanks of immunodeficient mice. Comparative immunohistochemistry was performed on xenografts and primary human melanoma sections. RESULTS: D10 cells expressed CD133 with a significantly higher clonogenic capacity as compared to CD133- cells. Na8, D10, and HBL cells formed spheroids on poly-HEMA-coated flasks. D10, Me39, RE, and WM115 cells expressed at least 2 of the 3 regulatory core transcription factors SOX2, NANOG, and OCT4 involved in the maintenance of stemness in mesenchymal stem cells. Gene expression profiling on CD133+ and CD133- D10 cells revealed 68 up- and 47 downregulated genes (+/-1.3 fold). Two genes, MGP and PROM1 (CD133), were outstandingly upregulated. CD133+ D10 cells formed tumors in NSG mice contrary to CD133- cells and CD133 expression was detected in xenografts and primary human melanoma sections using immunohistochemistry. CONCLUSIONS: Established melanoma cell lines exhibit, to variable extents, the typical features of CSCs. The tumorigenic cell line D10, expressing CD133 and growing in spheroids and might qualify as a potential model of melanoma CSCs.

Containment and contouring (CoCoon) technique: a biologically adequate approach to less invasive autogenous preimplant augmentation of bone.

We have analysed retrospectively whether the less invasive zygomatic buttress graft is able to meet the dimensional and biological requirements of preimplant augmentation of bone. A total of 273 patients were treated by zygomatic buttress graft, of whom 42 (12 men and 30 women) met the criteria for inclusion. Intensity of pain was judged by a visual analogue score (VAS). Complications of grafting were evaluated, and dental implants were studied on clinical and radiographic examinations. The Schneiderian membrane was perforated in 13 cases (28%). The mean (SD) postoperative VAS was 3.1 (0.9) at the donor site. The mean (SD) follow-up after implant was 17(8) months. Two grafts were lost, one from initial dehiscence and later infection, and the other from infection. The mean (SD) marginal resorption of bone graft was 0.5 (0.7) mm. No implant was lost during the observation period. The zygomatic buttress graft meets the biological and dimensional requirements of augmentation of bone before implant that allows the dental implants to survive with satisfactory prosthetic rehabilitation.

Optic nerve monitoring.

Orbital and anterior skull base surgery is generally performed close to the prechiasmatic visual pathway, and clear strategies for detecting and handling visual pathway damage are essential. To overcome the common problem of a missed clinical examination because of an uncooperative or unresponsive patient, flash visual evoked potentials and electroretinograms should be used. These electrophysiologic examination techniques can provide evidence of intact, pathologic, or absent conductivity of the visual pathway when clinical assessment is not feasible. Visual evoked potentials and electroretinograms are thus essential diagnostic procedures not only for primary diagnosis but also for intraoperative evaluation. A decision for or against treatment of a visual pathway injury has to be made as fast as possible due to the enormous importance of the time elapsed with such injuries; this can be achieved additionally using multislice spiral computed tomography. The first-line conservative treatment of choice for such injuries is megadose methylprednisolone therapy. Surgery is used to decompress the orbital compartment by exposure of the intracanalicular part of the optic nerve in the case of optic canal compression. Modern craniomaxillofacial surgery requires detailed consideration of the diagnosis and treatment of traumatic visual pathway damage with the ultimate goal of preserving visual acuity.

In Vitro Effects of External Pressure Changes on the Sealing Ability under Simulated Diving Conditions.

Aim. To measure and validate the permeability of pressure changes in correlation to different root filling techniques. Methods. Eighty extracted single-rooted teeth were randomly assigned to one of eight groups of ten teeth. Following standardized instrumentation and irrigation, root canal fillings were performed using either cold lateral condensation, a warm carrier-based gutta-percha obturation technique, a warm carrier-based Resilon, or warm gutta-percha compaction with the downpack/backfill technique. After insertion of a pressure sensor within the pulp chamber ten teeth of each group then underwent simulated dives with pressure measurement and the other ten a dye penetration test during simulated dives to 5.0 bar. Differences were analyzed statistically (P < 0.05) using one-way analysis of variance (ANOVA). Results. When the warm carrier-based gutta-percha obturation technique and vertical gutta-percha obturation techniques were used, there was significant lower intrapulpal pressure to experimental chamber pressure (P > 0.05). When cold lateral condensation or carrier-based Resilon as used, pressure was sometimes almost completely equalized. Conclusions. Warm gutta-percha obturation techniques provide a largely pressure-tight seal whereas the Resilon obturation technique and cold lateral condensation appear to be unsuitable to pressure changes.

Bisphosphonate-associated osteonecrosis of the mandible: reliable soft tissue reconstruction using a local myofascial flap.

For the treatment of bisphosphonate-associated osteonecrosis of the jaw (BP-associated ONJ), poor cure rates are reported. In many cases, repeated osseous exposition and infection may occur. The currently recommended management of affected patients is antibiotic treatment and bony decortication, which is often complicated by soft tissue deficits due to chronic infection. In severe cases osteonecrosis can be managed often only by continuity resections of the mandible. For this purpose, we developed a new surgical procedure, which allows an effective closure of difficult jaw wounds in the lateral mandible. In the last 3 years, 20 patients with BP-associated osteonecrosis of the lower jaw were treated successfully with a modified defect-covering method using a myofascial flap. A mylohyoid muscle flap was detached from mylohyoid line and used to cover the bony defect. During 19 months mean follow-up, 90% of patients were asymptomatic, the oral mucosa was intact, and no exposed bone was observed. In consequence, we are able to demonstrate that a mylohyoid muscle flap provides a reliable wound closure in the lower jaw in patients treated with BPs. Although there are still no consensual therapy guidelines for patients affected by BP-associated ONJ, the results of the presented study provide evidence for an effective surgical therapy with long-term success. Covering compromised bone with well-vascularized tissue, a muscle flap, increased healing chances by enabling and supporting the necessary nutrition and defense against opportunistic infections. This therapy concept showed a good clinical outcome.

A quantitative approach to orbital decompression in Graves' disease using computer-assisted surgery: a compilation of different techniques and introduction of the "temporal cage".

PURPOSE: Since 1911, when Dollinger first described surgical orbital decompression, many different techniques and approaches have been described, including 1-, 2-, and 3-wall decompressions with orbital fat removal. The indications for surgical treatment have been widened and include additional to optic neuropathy severe proptosis causing exposure keratopathy and disfigurement. Popular techniques for surgical decompression are the transantral or transpalpebral approach to the medial wall and orbital floor. Sometimes theses approaches are combined with lateral canthotomy incisions for access to the lateral wall ("3-wall decompression"). This report shows a compilation of different techniques using computer-assisted surgery for a 3-wall decompression with the introduction of the "temporal cage" in patients suffering from Graves' disease and the combination with zygomatic bone osteotomy. PATIENTS AND METHODS: Twelve patients suffering from Graves' disease presented for surgical treatment in our clinic. For surgical planning, a computed tomographic scan with navigation markers was carried out. The navigation was planned with voxel-based navigation software (VoXim or BrainLab). RESULTS: Of the patients, 1 had unilateral and 11 had bilateral decompressions. Of the 11 patients with bilateral procedures, 1 patient underwent simultaneous and 10 underwent sequential procedures. The 3-wall decompression in all cases was performed by transconjunctival approach. Temporary double vision could be observed in all cases. There was a significant reduction in proptosis. CONCLUSION: It was concluded that this approach and the computer-assisted surgery would be the operation of first choice when there is an indication for orbital decompression.

Increase in periosteal angiogenesis through heat shock conditioning.

OBJECTIVE: It is widely known that stress conditioning can protect microcirculation and induce the release of vasoactive factors for a period of several hours. Little, however, is known about the long-term effects of stress conditioning on microcirculation, especially on the microcirculation of the periosteum of the calvaria. For this reason, we used intravital fluorescence microscopy to investigate the effects of heat shock priming on the microcirculation of the periosteum over a period of several days. METHODS: Fifty-two Lewis rats were randomized into eight groups. Six groups underwent heat shock priming of the periosteum of the calvaria at 42.5°C, two of them (n = 8) for 15 minutes, two (n = 8) for 25 minutes and two (n = 8) for 35 minutes. After 24 hours, a periosteal chamber was implanted into the heads of the animals of one of each of the two groups mentioned above. Microcirculation and inflammatory responses were studied repeatedly over a period of 14 days using intravital fluorescence microscopy. The expression of heat shock protein (HSP) 70 was examined by immunohistochemistry in three further groups 24 hours after a 15-minute (n = 5), a 25-minute (n = 5) or a 35-minute (n = 5) heat shock treatment. Two groups that did not undergo priming were used as controls. One control group (n = 8) was investigated by intravital microscopy and the other (n = 5) by immunohistochemistry. RESULTS: During the entire observation period of 14 days, the periosteal chambers revealed physiological microcirculation of the periosteum of the calvaria without perfusion failures. A significant (p < 0.05) and continuous increase in functional capillary density was noted from day 5 to day 14 after 25-minute heat shock priming. Whereas a 15-minute exposure did not lead to an increase in functional capillary density, 35-minute priming caused a significant but reversible perfusion failure in capillaries. Non-perfused capillaries in the 35-minute treatment group were reperfused by day 10. Immunohistochemistry demonstrated an increase in cytoprotective HSP70 expression in the periosteum after a 15-minute and a 35-minute heat shock pretreatment when compared with the control group. The level of HSP70 expression that was measured in the periosteum after 25 minutes of treatment was significantly higher than the levels observed after 15 or 35 minutes of heat shock exposure. CONCLUSION: A few days after heat shock priming over an appropriate period of time, a continuous increase in functional capillary density is seen in the periosteum of the calvaria. This increase in perfusion appears to be the result of the induction of angiogenesis.

A novel approach for studying microcirculation in bone defects by intravital fluorescence microscopy.

Angiogenic and inflammatory responses to biodegradable scaffolds were previously studied using the dorsal skinfold chamber for testing different scaffold materials. In this model, the angiogenic response originates from the soft tissue of the skin. Herein, we introduce a new model that allows the study of developing microcirculation of bone defects for testing tissue-engineered constructs. A bone defect was prepared in the femur of Balb/c mice by inserting a pin for intramedullary fixation, and a custom-made observation window fixed over the defect allowed constant observation. This study included three different groups: empty defect (control), defect filled with porous poly(L-lactide-co-glycolide), and beta-tricalcium-phosphate scaffolds. Starting from 6 days after surgery, angiogenesis, neovascularization, leukocyte-endothelial cell interaction, and microvascular permeability were analyzed over 22 days by using intravital fluorescence microscopy. The empty defects showed no signs of angiogenesis during the observation period, but a distinct increase of capillary density was detected in the scaffold-containing defects. Surprisingly, the histological sections of the scaffold-treated defects showed new bone formation 22 days after implantation. We present a new bone chamber model for intravital long-term study of scaffold materials suitable for bone reconstruction in mice by using fluorescence microscopy.

Effect of neoadjuvant chemoradiation and postoperative radiotherapy on expression of heat shock protein 70 (HSP70) in head and neck vessels.

BACKGROUND: Preoperative radiotherapy and chemotherapy in patients with head and neck cancer result in changes to the vessels that are used to construct microsurgical anastomoses. The aim of the study was to investigate quantitative changes and HSP70 expression of irradiated neck recipient vessels and transplant vessels used for microsurgical anastomoses. METHODS: Of 20 patients included in this study five patients received neoadjuvant chemoradiation, another five received conventional radiotherapy and 10 patients where treated without previous radiotherapy. During surgical procedure, vessel specimens where obtained by the surgeon. Immunhistochemical staining of HSP70 was performed and quantitative measurement and evaluation of HSP70 was carried out. RESULTS: Conventional radiation and neoadjuvant chemoradiation revealed in a thickening of the intima layer of recipient vessels. A increased expression of HSP70 could be detected in the media layer of the recipient veins as well as in the transplant veins of patients treated with neoadjuvant chemoradiation. Radiation and chemoradiation decreased the HSP70 expression of the intima layer in recipient arteries. Conventional radiation led to a decrease of HSP70 expression in the media layer of recipient arteries. CONCLUSION: Our results showed that anticancer drugs can lead to a thickening of the intima layer of transplant and recipient veins and also increase the HSP70 expression in the media layer of the recipient vessels. In contrast, conventional radiation decreased the HSP70 expression in the intima layer of arteries and the media layer of recipient arteries and veins. Comparing these results with wall thickness, it was concluded, that high levels of HSP70 may prevent the intima layer of arteries and the media layer of vein from thickening.

Reconstruction of oral mucosal defects using the nasolabial flap: clinical experience with 22 patients.

BACKGROUND: Various surgical options are available for reconstruction of intraoral soft tissue defects. For smaller defects of the oral mucosa in different anatomic locations of the oral cavity the nasolabial flap is a very useful and simple alternative to other pedicled flaps and free flaps. METHODS: The results of reconstruction of oral mucosal defects or facial skin defects using 29 nasolabial flaps in 22 patients were reviewed retrospectively. RESULTS: The patient group consisted of 16 patients (70%) with squamous cell carcinoma of the oral cavity, 2 patients (10%) with cystic lesions of the maxilla, 3 patients (15%) with osteonecrosis of the jaw, and 1 patient with an oral metastasis of a lung carcinoma. Healing was uneventful in 93%, partial or complete flap loss was observed in 7%. CONCLUSIONS: The nasolabial flap is a valuable alternative for reconstruction of smaller defects of the oral cavity in particular in older and medically compromised patients.

Reconstruction of mandibular defects - clinical retrospective research over a 10-year period -.

BACKGROUND: Functional and cosmetic defects in the maxillofacial region are caused by various ailments and these defects are addressed according to their need. Simplicity of procedure, intact facial function and esthetic outcome with the least possible donor site morbidity are the minimum requirements of a good reconstruction. Oro-mandibular reconstruction, although a challenge for the head and neck reconstructive surgeon, is now reliable and highly successful with excellent long-term functional and aesthetic outcomes with the use of autogenous bone grafts. Reconstruction of trauma- or mandibular oncologic defects with bony free flaps is considered the gold standard. However the the optimal reconstruction of mandibular defects is still controversial in regards to reconstructive options which include the donor site selection and the timing of surgery. The purpose of this study was to determine the outcome of different osseous reconstruction options using autogenous bone grafts for mandibular reconstructions. METHODS: This study was carried out on 178 patients with mandibular bone defects. They were reconstructed with autogenous bone grafts from different donor sites. At post operative visits they were evaluated for functional and cosmetic results. RESULTS: The success rate found in this study was around 90%. Only 7.6% of the cases showed poor results regarding facial contours and mouth opening. All other patients were satisfied with their cosmesis and mouth opening at the recipient sites was in the normal range during last follow-up visits. Donor sites were primarily closed in all cases and there was no hypertrophic scar. CONCLUSION: Based on this study, autogenous bone grafts are a reliable treatment modality for the reconstruction of mandibular bone defects with predictable aesthetic and functional outcomes. As the free vascularized fibular flap has the least resorption and failure rate, it should be the first choice for most cases of mandiblular reconstruction.

Comparably accelerated vascularization by preincorporation of aortic fragments and mesenchymal stem cells in implanted tissue engineering constructs.

The demanding need for tissue replacement resulted in manifold approaches for the construction of different tissues. One common problem which hampers the clinical usage of tissue engineering constructs is a limited vascularization. In an attempt to accelerate the vascularization of tissue engineering constructs we compared the usage of bone marrow mesenchymal stem cells (bmMSCs) and fragments derived from the aorta in vivo. Tissue engineering constructs composed of PLGA scaffolds containing Matrigel (n = 8), aortic fragments embedded in Matrigel (n = 8), bmMSCs embedded in Matrigel (n = 8), and aortic fragments embedded in Matrigel combined with bmMSCs (n = 8) were implanted into dorsal skinfold chambers of balb/c mice and analyzed repetitively over 14 days. In all groups a weak inflammatory response was transiently apparent. Vascularization was significantly (p = 0.05) accelerated in bmMSC and aortic fragments containing constructs compared with Matrigel alone, demonstrated by a distinctly increased microvascular density throughout the whole experiment. The combination of bmMSCs and aortic fragments showed no additional effect compared with bmMSCs and aortic fragments alone. The accelerated vascularization and microvascular density of tissue engineering constructs triggered by bmMSCs and aortic fragments is comparable. Thus aortic fragments provide a new promising source for clinical relevant tissue engineering constructs.

Prolongated survival of osteoblast-like cells on biodegradable scaffolds by heat shock preconditioning.

The implantation of tissue-engineered constructs leads to hypoxic and physical stress to the seeded cells until they were reached by a functional microvascular system. Preconditioning of cells with heat shock induced heat shock proteins, which can support the cells to survive a subsequent episode of stress that would otherwise be lethal. Preconditioning of tissue-engineered constructs resulted in significantly higher number of surviving osteoblast-like cells (OLC). At the 6th and 10th day, angiogenic response was found comparative to poly(L-lactide-co-glycolide) (PLGA) scaffolds vitalized with either unconditioned or preconditioned OLC. However, they were significantly enhanced compared with the nonvitalized collagen-labeled PLGA scaffolds. This study demonstrates that vitalization of PLGA scaffolds with OLC accelerates the angiogenic response induced by the surrounding host tissue. In addition, heat shock preconditioning significantly enhances the survival rate of the OLC that are seeded on these scaffolds. Thus, vitalization of substitutes with adequately pretreated OLC may promise biologically adequate osseous restorations.