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Biomedical subjects

Rolf Ewers

Publications and source records attributed to Rolf Ewers.

At least 19 recordsLinked to original sources
PubMed2006

Open versus arthroscopic surgery for internal derangement of the temporomandibular joint: a retrospective study comparing two centres' results using the Jaw Pain and Function Questionnaire.

OBJECTIVES: Surgical procedures currently used for treating of internal derangement of the temporomandibular joint vary widely. Although different studies present favourable results following open or arthroscopic TMJ surgery, the criteria for a successful treatment outcome are not always defined identically. In a retrospective study, two groups of patients who underwent either open or arthroscopic surgery for internal derangement (stages III-V according to Wilkes' classification) were investigated using the so-called JPF-Questionnaire. PATIENTS AND METHODS: The Kyoto collective (group 1) consisted of 28 patients, 2 men and 26 women, who underwent arthroscopic surgery. At the time of surgery, age ranged from 13 to 77 years (mean 32.8 y). The postoperative follow-up period ranged from 4 years and 4 months to 5 years and 9 months. Twelve of the 28 patients were classified as stage III, 10 as stage IV and 6 were classified as stage V (according to Wilkes) at the time of surgery. The Vienna collective (group 2) also consisted of 28 patients, 2 men and 26 women, who underwent open meniscoplasty or discectomy. At the time of surgery age ranged from 17 to 55 years (mean 31.6 years). The postoperative follow-up ranged from 5 to 6 years and 9 months. Fourteen of the 28 patients were classified as stage III, 11 as stage IV and 3 were classified as stage V (according to Wilkes) at the time of surgery. The results of the JPF-Questionnaire of the two groups were compared by Wilcoxon 2-sample tests. The Japanese version was applied, while in Austria the German version of this questionnaire was applied. RESULTS: At a level of significance alpha=0.05 no significant difference was found when comparing the subgroups (Wilkes stages III, IV and V) or both groups of patients 5 years after temporomandibular joint surgery. CONCLUSION: There cannot be any clear indication for only one of the treatment modalities as similar results were noted following open or arthroscopic temporomandibular joint surgery. Nevertheless, arthroscopic surgery is a minimally invasive procedure resulting in a shorter or no time of hospitalization when compared with open surgery and therefore is preferred by many surgeons nowadays.

Adolescent↗
PubMed2006

Osteonecrosis of the jaws and bisphosphonate treatment in cancer patients.

PURPOSE: Osteonecrosis of the jaws is described as an intraoral complication after administration of intravenous nitrogen-containing bisphosphonates. In a retrospective study, patients with osteonecrosis of the jaws after bisphosphonate treatment were evaluated with regard to diagnostic investigations and therapeutic management. PATIENTS AND METHODS: Seventeen patients with osteonecrosis of the jaws after bisphosphonate treatment who were referred to our department between July 2004 and June 2005 were included in this study. Computer tomography, magnetic resonance imaging, scintigraphy, bacteriology and biopsy were used in diagnostic evaluation. All patients were treated surgically. RESULTS: The reasons for bisphosphonate treatment were multiple myeloma in 12 patients, breast cancer with bone metastasis in four patients and histiocytosis X in one patient. Five patients had received intravenous pamidronate and 12 patients zoledronic acid. The median number of treatment cycles for pamidronate was 36 times (range 4-100) in 38 months (range 4-100). Zolendric acid was given 23.5 times (range 5-39) in 26 months (range 5-39). Nine patients had a lesion in the mandible, eight in the maxilla. Clinical symptoms were exposed bone, pain and local inflammation of the mucosa. Computer tomography showed sclerotic areas in the osteonecrosis zone. The biopsy did not show a metastatic lesion. Sequestrectomy and decortication was adequate in the follow-up. CONCLUSION: Nitrogen-containing bisphosphonates appear to be associated with the risk of developing osteonecrosis of the jaws. To reduce this risk, patients should be evaluated by a dentist before beginning treatment with intravenous bisphosphonates.

Adult↗
PubMed2006

Point-to-point computer-assisted navigation for precise transfer of planned zygoma osteotomies from the stereolithographic model into reality.

PURPOSE: To evaluate the feasibility and accuracy of a new method for planning and realizing zygomatic osteotomies in cases of established post-traumatic deformities using stereolithographic (SL) models and computer assisted navigation. PATIENTS AND METHODS: In 5 patients, osteotomy and repositioning of the zygomatic complex was planned using SL models. The desired position of the zygoma in the patient was determined by fixing individualized osteosynthesis plates to predefined screw positions. The SL model and the patient were registered to the same 3-dimensional computed tomography data set via an occlusal reference frame on the patient and corresponding reference markers on the model. Prebent osteosynthesis plates from the surgical simulation on the model were fixed to corresponding screw positions on the patient, which were located by computer-assisted navigation. Evaluation of accuracy was performed by image fusion of postoperative computed tomography scans of the model and the patient. RESULTS: Clinical outcome was satisfactory in all cases. The evaluation by image fusion showed alignment of the patient's and the model's zygoma in 4 of 5 cases. Mean measured distance between screw positions in the models and the patients were 1.1 +/- 0.3 mm for 44 screws. In 1 patient the treatment plan was changed intraoperatively because of unforeseen soft tissue limitations. CONCLUSION: Point-to-point navigation is an accurate method to transfer the planning of a complex osteotomy from the SL model to the actual surgical procedure. Surgery is facilitated considerably because repositioning and osteosynthesis are achieved in 1 step.

Adult↗
PubMed2006

Influence of previous radiotherapy on free tissue transfer in the head and neck region: evaluation of 455 cases.

OBJECTIVE/HYPOTHESIS: The aim of this retrospective cohort study was to investigate the effect of prior radiotherapy (XRT) on the outcome of microvascular free tissue transfer in the head and neck region. METHODS: Four hundred fifty-five patients, subdivided into three groups, were analyzed. Groups I (no previous XRT, n=110), II (previous radiochemotherapy with 50 Gy focus dosage in the primary treatment regime for oral cancer, n=322), and III (secondary reconstruction after XRT-induced complications, n=23) were compared regarding flap success rate, postoperative complications, postoperative mortality, duration of intensive care (DOIC), and hospitalization (DOH). RESULTS: Flap success did not differ significantly across groups (I: 95.5%, II: 93.2%, III: 91.3%. Risk of postoperative complications was significantly lower for group I (12.7%) compared with groups II (23.9%) and III (39.1%). DOIC and DOH were significantly shorter for patients in group I than for those in groups II and III. CONCLUSIONS: XRT before free tissue transfer does not significantly increase flap loss or postoperative mortality but does increase postoperative complications and length of hospitalization.

Adolescent↗
PubMed2006

Implant survival in mandibles of irradiated oral cancer patients.

OBJECTIVE: The aim of this study was to analyze long-term implant survival in the mandible after radiotherapy and radical surgery in oral cancer patients. STUDY DESIGN: Between 1990 and 2003, 71 patients (15 females, 56 males; average age 57.8 years, range 16-84.1 years) were treated with dental implants after radiochemotherapy and ablative surgery of oral cancer. Radiation therapy was delivered in daily fractions of 2 Gy given on 25 days (total dose of 50 Gy). Oral defects were reconstructed microsurgically with jejunal, iliac crest or radial forearm grafts. Thereafter 316 dental implants were placed in the non-irradiated residual bone (84; 27%), irradiated residual bone (154; 49%) or grafted bone (78; 25%) at various intervals (mean interval 1.41 (+/- 1.01) years, range 0.34-6.35 years). RESULTS: The mean follow-up time after implant insertion was 5.42 (+/- 3.21) years (range 0.3-13.61 years). The overall 2-, 3-, 5-, and 8-year survival rates of all implants were 95%, 94%, 91% and 75%. Forty-four implants were lost in 21 patients during the observation period. Irradiation of the mandibular bone showed significantly (P = 0.0028) lower implant survival compared with non-irradiated mandibular bone. The 8-year survival rate in the non-irradiated residual bone (two loss), irradiated residual bone (29 loss) or grafted bone (13 loss) were 95%, 72% and 54%, respectively. Time of implantation after irradiation showed no statistically significant influence. Implant brand, length or diameter or the incidence of resective surgery on the mandible and gender of patients had no statistically significant influence on implant survival. CONCLUSION: Radiation therapy with 50 Gy was significantly related to shorter implant survival in mandibular bone. Survival was lowest in grafted bone. Time of implant placement had no statistically significant influence on survival under the conditions of this study. Although implant survival is lower in irradiated mandibles, implants significantly facilitate prosthodontic treatment and enhance outcome of oral rehabilitation in cancer patients.

Adolescent↗
PubMed2006

Accuracy of treatment planning based on stereolithography in computer assisted surgery.

Three-dimensional stereolithographic models (SL models), made of solid acrylic resin derived from computed-tomography (CT) data, are an established tool for preoperative treatment planning in numerous fields of medicine. An innovative approach, combining stereolithography with computer-assisted point-to-point navigation, can support the precise surgical realization of a plan that has been defined on an SL model preoperatively. The essential prerequisites for the application of such an approach are: (1) The accuracy of the SL models (including accuracy of the CT scan and correspondence of the model with the patient's anatomy) and (2) the registration method used for the transfer of the plan from the SL model to the patient (i.e., whether the applied registration markers can be added to the SL model corresponding to the markers at the patient with an accuracy that keeps the "cumulative error" at the end of the chain of errors, in the order of the accuracy of contemporary navigation systems). In this study, we focus on these two topics: By applying image-matching techniques, we fuse the original CT data of the patient with the corresponding CT data of the scanned SL model, and measure the deviations of defined parameter (e.g., distances between anatomical points). To evaluate the registration method used for the planning transfer, we apply a point-merge algorithm, using four marker points that should be located at exactly corresponding positions at the patient and at connective bars that are added to the surface of the SL model. Again, deviations at defined anatomical structures are measured and analyzed statistically. Our results prove sufficient correspondence of the two data sets and accuracy of the registration method for routine clinical application. The evaluation of the SL model accuracy revealed an arithmetic mean of the relative deviations from 0.8% to 5.4%, with an overall mean deviation of 2.2%. Mean deviations of the investigated anatomical structures ranged from 0.8 mm to 3.2 mm. An overall mean (comprising all structures) of 2.5 mm was found. The fiducial registration error of the point-merge algorithm ranged from 1.0 mm to 1.4 mm. The evaluated chain of errors showed a mean deviation of 2.5 mm. This study verifies that preoperative planning on SL models and intraoperative transfer of this plan with computer assisted navigation is a suitable and sufficiently reliable method for clinical applications.

Algorithms↗
PubMed2006

Particle size of hydroxyapatite granules calcified from red algae affects the osteogenic potential of human mesenchymal stem cells in vitro.

Hydroxyapatite (HA) microparticles as a carrier in an injectable tissue-engineered bone filler are considered promising candidates for the treatment of small bone defects in the craniomaxillofacial region. HA granules calcified from red algae, varying in size, were evaluated in vitro for their suitability to be used as a carrier for human mesenchymal stem cells (hMSCs). Three groups of granules were produced in grain sizes of 10-100, 200-500 and 600-1,000 mum. After seeding and culturing hMSCs under osteogenic differentiation conditions onto HA particles for 3, 6 and 9 days, cellular proliferation (tetrazolium salt, XTT), alkaline phosphatase (ALP)-specific activity and total protein synthesis were investigated. The osteoblastic phenotype of the cells was evaluated by assaying the bone-specific genes osteocalcin, osteopontin and collagen type I. XTT assay revealed significantly higher (p < 0.01) proliferation of cells grown on the smallest grain size after 9 days of culture. Regarding ALP-specific activity, significantly higher levels of activity were detected in cells grown on the smallest grain size. Different grain sizes had no significant effects on the secretion of osteocalcin and osteopontin. Collagen type I production was significantly higher (p < 0.05) in cells grown on the biggest grain size in comparison with the two other grain sizes. These results show that the particle size of HA microparticles affects the osteogenic potential of cultured hMSCs and lead to the conclusion that particle size has differential effects on ALP-specific activity and collagen type I production.

Alkaline Phosphatase↗
PubMed2005

Expression pattern of the chromosome 21 transcription factor Ets2 in cell-seeded three-dimensional bone constructs.

The ability to generate new bone for reconstructive surgery use is a major clinical need. Tissue engineering with osteoprogenitor cells isolated from the patient's periosteum and seeded into bioresorbable scaffolds offers a promising approach to the generation of skeletal tissue. To our knowledge, there is no description about the expression of Ets2 in tissue engineered "bone neotissue." The aim of our study was to manufacture cell-seeded three-dimensional bone constructs with human periosteal cells on poly (lactic-co-glycolic acid) polymer fleeces to describe the expression pattern of Ets2 and its target genes osteocalcin and osteopontin; expression analysis of type I collagen, core-binding factor-1, alkaline phosphatase, and osteonectin; the ability of matrix mineralization and ALP enzymatic activity showed the osteogenic character of the constructs. A significant correlation between the expression of Ets2 and osteopontin mRNA (r = -0.70; p < 0.05) could be shown. A 1.35-fold increase of Ets2 expression from days 1 to 9 was detected, followed by a slight decrease from days 11 to 15. Until the end of the culture period, the expression of Ets2 reached a comparable high level as detected on day 9. In contrast, the expression level of osteopontin mRNA reached a maximum at day 7, followed by a progressive 3.04-fold decrease until day 21. This study shows for the first time that Ets2 gene and its transcriptional target genes are expressed in tissue-engineered bone constructs. These findings have the potential to provide much-needed information about the role and function of Ets2 in human osteogenesis processes and creation of "bone neotissue."

Alkaline Phosphatase↗
PubMed2005

Stability of miniature electromagnetic tracking systems.

This study aims at a comparative evaluation of two recently introduced electromagnetic tracking systems under reproducible simulated operating-room (OR) conditions: the recently launched Medtronic StealthStation, Treon-EM and the NDI Aurora. We investigate if and to what extent these systems provide improved performance and stability in the presence of surgical instruments as possible sources of distortions compared with earlier reports on electromagnetic tracking technology. To investigate possible distortions under pseudo-realistic OR conditions, a large Langenbeck hook, a dental drill with its handle and an ultrasonic (US) scanhead are fixed on a special measurement rack at variable distances from the navigation sensor. The position measurements made by the Treon-EM were least affected by the presence of the instruments. The lengths of the mean deviation vectors were 0.21 mm for the Langenbeck hook, 0.23 mm for the drill with handle and 0.56 mm for the US scanhead. The Aurora was influenced by the three sources of distortion to a higher degree. A mean deviation vector of 1.44 mm length was observed in the vicinity of the Langenbeck hook, 0.53 mm length with the drill and 2.37 mm due to the US scanhead. The maximum of the root mean squared error (RMSE) for all coordinates in the presence of the Langenbeck hook was 0.3 mm for the Treon and 2.1 mm for the Aurora; the drill caused a maximum RMSE of 0.2 mm with the Treon and 1.2 mm with the Aurora. In the presence of the US scanhead, the maximum RMSE was 1.4 mm for the Treon and 5.1 mm for the Aurora. The new generation of electromagnetic tracking systems has significantly improved compared to common systems that were available in the middle of the 1990s and has reached a high level of technical development. We conclude that, in general, both systems are suitable for routine clinical application.

Artifacts↗
PubMed2005

HA/TCP compounding of a porous CaP biomaterial improves bone formation and scaffold degradation--a long-term histological study.

In the present study, two biphasic calcium phosphate biomaterials (BCP) with HA/TCP ratios of 50/50 and 30/70 were obtained from a pure HA biomaterial. The biomaterials which showed the same three-dimensional geometry were implanted into corticocancellous costal defects of sheep. In the specimens of all three biomaterials, abundant bone formation, mineral dissolution from the biomaterial scaffolds, and active cellular resorption of the scaffolds was present after 6 and 12 months. Backscattered electron microscopy showed bone invasion into the pores of the scaffolds and micromechanical interlocking at the bone/biomaterial interface without intervening soft tissue. The pattern of bone formation and scaffold resorption was different for cortical and cancellous bone. No time-based effect, however, was observed. Overall, the BCP biomaterials had formed significantly more bone than the HA biomaterial. Also, scaffold resorption, which was followed by a replacement with newly formed bone, was significantly higher in the BCP biomaterials. Although no significant differences were observed between both BCP biomaterials, the present study had confirmed the assumption that HA/TCP compounding was suitable to improve bone formation and scaffold resorption in the investigated biomaterials and at the same time maintain the osteoconductive properties of the scaffolds.

Absorbable Implants↗
PubMed2005

Self-reinforced biodegradable plates and screws for fixation of zygomatic fractures.

PURPOSE: The aim of this retrospective clinical study was to evaluate zygomatic fracture fixation with the BioSorbFX osteosynthesis system by assessing stability of reduction as well as complications in the first postoperative year and by conducting a survey to document surgeons' opinions on biodegradable osteosynthesis for this indication. MATERIAL: From January to September 2003, 25 patients with displaced non-infected unilateral fracture of the zygoma were operated upon (m:f = 20:5; age 17-81 years; mean 39.4 years) using the BioSorbFX 2.0 and/or 1.5 mm osteosynthesis systems. METHODS: A: Clinical and radiographic examinations were carried out immediately postoperatively and after 1, 3, 6, 9 and 12 months. METHODS: B: Surgeons were asked to participate in a survey critically evaluating their experience with biodegradable osteosynthesis systems. RESULTS: A: All fractures of the zygoma healed uneventfully. An excessive soft tissue reaction due to the degradation process was not seen. Three minor complications which resolved after local therapy occurred in the immediate postoperative phase. RESULTS: B: In the survey, the handling of biodegradable plates in general was rated worse than metal plate osteosynthesis. CONCLUSION: Fixation of fractures of the zygoma with the BioSorbFX system was simple and safe. The fixations remained stable and bony healing was uneventful. Postoperative complications were few, of a minor nature and not related to the process of biodegradation.

Absorbable Implants↗
PubMed2005

Mutation analysis of CLPTM 1 and PVRL 1 genes in patients with non-syndromic clefts of lip, alveolus and palate.

INTRODUCTION: Non-syndromic cleft lip with or without cleft palate (CL/P), is one of the most common birth defects, but its aetiology is largely unknown. The aim of this study was to determine the sequence changes of the Cleft Lip and Palate Transmembrane Protein 1 (CLPTM 1) and Poliovirus Receptor Related 1 (PVRL 1) genes in patients with non-syndromic complete clefts of lip, alveolus and palate and to correlate these findings with clinical features. PATIENTS AND METHODS: 25 patients were analysed (14 male and 11 female, aged 4-10 years) of European descent (9 patients with right, 9 with left and 7 patients with bilateral CLAP) and 25 controls, respectively. Exons 2-14 of the CLPTM1 and exons 1-6 of the PVRL1 gene were analysed by a direct sequencing method using DNA extracted from whole blood. RESULTS: A novel in frame Glu441-Gly442 ins Glu mutation of the PVRL 1 gene in combination with novel exon mutations Gly331Gly, Ala88Ala, Pro309Pro and intron change IVS7-10G/A of the CLPTM 1 gene were found in 9 patients. The Glu441-Gly442 ins Glu mutation and the intron change IVS7-10G/A were not detected in 25 controls. CONCLUSION: These results suggest that a simultaneous occurrence of PVRL1 and CLPTM 1 gene mutations in cleft patients does not correlate with the type of cleft (left, right, bilateral) or the gender of the patients. If a combination of the intron change IVS7-10G/A, exon changes Gly331Gly, Ala88Ala and Pro309Pro of the CLMPT 1 gene and Glu441-Gly442 ins Glu mutation of the PVRL 1 gene could be a genetic factor for non-syndromic clefts of the primary and the secondary palates, it is important to investigate more patients and controls.

Alanine↗
PubMed2005

Analysis of cell-seeded 3-dimensional bone constructs manufactured in vitro with hydroxyapatite granules obtained from red algae.

PURPOSE: Bone tissue engineering is a promising approach for the treatment of defective or lost bone in the maxillofacial region. Biocompatible and biodegradable scaffolds seeded with living cells are used to create functional tissue for load-bearing bone reconstruction. The aim of this study was to manufacture cell-seeded 3-dimensional bone constructs based on hydroxyapatite ceramic granule calcified from red algae and mesenchymal cambial-layer precursor cells. The ability of these cells to grow on hydroxyapatite ceramic was quantitatively investigated to evaluate 3-dimensional bone constructs for their potential use in bone tissue engineering. MATERIALS AND METHODS: Mesenchymal cambial-layer precursor cells were isolated from mandibular periosteum biopsy samples of 3 patients. To manufacture 72 bone constructs, these cells and hydroxyapatite ceramic granules (C GRAFT/Algipore; Clinician's Preference LLC, Golden, CO) were cultivated under osteogenic differentiation conditions in a rotating wall vessel system. After 6 and 21 days, histologic examination and scanning electron microscopy were performed. The absolute DNA content, protein synthesis, and alkaline phosphatase activity were also quantified. The osteoblastic phenotype of the constructs was confirmed by the expression of bone-specific genes (osteocalcin, osteonectin, osteopontin, and core binding factor alpha1) using semiquantitative reverse transcription-polymerase chain reaction and Western blot analysis. RESULTS: Cells within the constructs showed good viability, which was evidenced by an increase in DNA content over the culture period. The decrease in alkaline phosphatase-specific activity could be an indicator of the maturation of cells and the induction of mineralization. The osteoblastic phenotype of the constructs was demonstrated on protein and at the RNA level over the entire culture period. CONCLUSION: We observed a positive effect of hydroxyapatite ceramic granules on mesenchymal cambial-layer precursor cell behavior in cell-seeded 3-dimensional bone constructs, indicating the potential applicability of C GRAFT/Algipore composites in bone tissue engineering.

Blotting, Western↗
PubMed2005

In vitro growth and differentiation of osteoblast-like cells on hydroxyapatite ceramic granule calcified from red algae.

PURPOSE: The purpose of this study was to analyze the interaction between osteoblast-like cells isolated from mandibular bone and hydroxyapatite ceramic bone substitute obtained from calcified red algae to assess the growth and differentiation of adherent cells on this biomaterial. MATERIALS AND METHODS: The macroporous ceramic material C GRAFT/Algipore (The Clinician's Preference LLC, Golden, CO) is composed of 100% hydroxyapatite and possesses specific mechanical and physiochemical properties. Osteoblast-like cells were seeded on 200 mg of biomaterial and cultured for 6 and 21 days under osteogenic differentiation conditions. Specific alkaline phosphatase activity, DNA, and protein content of the proliferating cells were analyzed. The morphology of the cells in contact with the biomaterial was examined by scanning electron microscopy. The osteoblastic phenotype of the cells was confirmed by analysis of the expression of bone-specific genes (osteocalcin, osteopontin and collagen type I) by semi-quantitative reverse transcriptase polymerase chain reaction. RESULTS: The DNA and protein content increased over the culture period. Scanning electron microscopy showed cells spreading on the surface of the biomaterials, covering the macropores, and colonizing the depth of the particles. The analysis of the expression patterns of bone-related genes confirmed the osteoblastic phenotype of the cultured cells. CONCLUSION: The results of this study showed that hydroxyapatite ceramic bone substitute obtained from calcified red algae support the proliferation and differentiation of human osteoblast-like cells on its surface in vitro and might be suitable for use as scaffolds in tissue engineering strategies in vivo.

Bone Substitutes↗
PubMed2005

Seven years of clinical experience with teleconsultation in craniomaxillofacial surgery.

PURPOSE: In this work the experiences from 50 telemedically supported treatments in craniomaxillofacial surgery are summarized and different setups for their technical realization are described. Furthermore, for the first time the innovative UMTS (universal mobile telecommunication system) is applied for the transmission of arthroscopic videos of the temporomandibular joint and other craniomaxillofacial structures. MATERIALS AND METHODS: The combination of computer-assisted navigation technology in augmented reality environments with telecommunication is used for execution of interactive stereotaxic teleconsultation. Furthermore, treatments without navigation are telemedically supported. This study is composed of 4 technical system configurations: 1) integrated services digital network (ISDN)-based videoconferencing without remote control of the navigation computer; 2) transmission control protocol/internet protocol (TCP/IP)-based interactive teleconsultation via bundled ISDN lines (including remote control of the navigation computer); 3) TCP/IP-based interactive teleconsultation via network; 4) combination of TCP/IP-connection and ISDN-based videoconferencing. The telemedically supported treatments are: orbitozygomatic osteotomies, positioning of the mandibular condyle in orthognathic surgery, insertion of implants, positioning of the maxilla in orthognathic surgery, distraction osteogenesis, arthroscopies of the temporomandibular joint, and operation simulations on stereolithographic models. The surgical interventions are evaluated on a 5-level system performance scale from the technical point of view. In a separate trial 20 videosequences of arthroscopies of the temporomandibular joint are transmitted via UMTS cellular phones and independently evaluated by 3 experts (ie, a total of 60 streamings) to investigate feasibility of this technology in the field of craniomaxillofacial surgery. RESULTS: In the years from 1996 to 2002 a total of 50 treatments were telemedically supported. All intraoperative applications were successfully finished; 48 of 60 UMTS transmissions were finished without any interruptions in constant quality, slight interruptions were observed in 8 tests, and a complete breakdown was observed during 4 streamings that required a restart of the transmission. Resolution was sufficient to diagnose even tiny anatomic structures inside the temporomandibular joint, but orientation was hardly recognizable. CONCLUSION: In many applications telecommunication technology can contribute to a quality improvement in cranio- and maxillofacial surgery because of the global availability of specialized knowledge. The required technical expenditure for teleconsultation crucially depends on the infrastructure that is already available at the clinic and the remote site. UMTS is a promising technology with the potential to be valuable in numerous craniomaxillofacial applications.

Arthroscopy↗
PubMed2005

Maxilla sinus grafting with marine algae derived bone forming material: a clinical report of long-term results.

PURPOSE: Autogenous bone grafting continues to be considered the gold standard for sinus grafting. For the past 15 years the author has used an alternative graft material and followed-up the input/output statistic of implants to evaluate if this material results similar to the autogenous bone graft. Histomorphometric evaluations of graft materials show how much new bone is formed and if the graft material is resorbed. MATERIALS AND METHODS: In our study we used a marine derived carbonated red algae that is chemically converted into hydroxyapatite (HA). This material is distributed worldwide as the Communauté Européenne approved material AlgiPore (Dentsply Friadent, Mannheim, Germany), as the US Food and Drug Administration approved material C GRAFT (The Clinician Preference LLC, Golden, CO), and the Russian approved material AlgOss (Unexim Co, Moscow, Russia). A total of 209 sinus grafts were performed on 118 patients who presented with a severely resorbed maxillary alveolar process with 1 to 5 mm (mean, 3.6 mm) of remaining bone. The available bone was comparable to Class D bone as described by Simion et al. After 6 months implants were placed and 6 months later the implants were loaded. RESULTS: From September 5, 1990, to September 1, 2004, the author performed 209 sinus grafts on 118 patients. The longest observation period of loaded implants in this study is 156 months (13 years). Implant loss was 27 out of 614 loaded implants (4.4%), showing a survival rate of 95.6%. Smokers and women over 50 are included. Although AlgiPore/C GRAFT/AlgOss (ACA) undergoes a resorption process, we found only 14% volume loss after 6.4 months compared with 49.5% after 6 months when autogenous bone was used. CONCLUSION: This retrospective study of over 14 years shows once again that the sinus lift procedure with grafting of the sinus floor and subsequent implant placement is a proven method. This 14-year longitudinal study shows that the marine derived HA material ACA in a mixture with approximately 10% autogenous collector bone and blood or platelet rich plasma is able to enhance enough new bone in 6 months to allow implant osseointegration after 6 more months with a high implant survival rate.

Absorbable Implants↗
PubMed2005

Experience with microvascular free flaps in preoperatively irradiated tissue of the oral cavity and oropharynx in 303 patients.

This study examined free flap reconstruction of surgical defects of the oral cavity and oropharynx after preoperative radiochemotherapy. Included in this analysis are 303 prospectively followed patients who underwent a multimodal treatment regime for advanced oral and oropharyngeal carcinoma. All patients received preoperative radiochemotherapy (Mitomycin C, 5-FU, 50 Gy), ablative surgery, and primary free flap reconstruction. Patient characteristics, surgical parameters like duration of surgery and ischaemia, size of defect, type of transplant, and clinical outcome parameters like duration of intensive care and hospitalization, type of complications, necessity and type of revision surgery were statistically evaluated. Overall flap success rate was 93.1%. Sixty seven patients required revision and 21 flaps (6.9%) were lost. Overall complication rate was 22.1%. Mean duration of intensive care (DOIC) and duration of overall postoperative hospitalization (DOH) were 11.0+/-9.6 days and 35.9+/-26.3 days, respectively. Flap success and flap related complications after 50 Gy focal radiation dosage were found in a comparable range as in published series of reconstructions in uncompromised tissue.

Adult↗