1,720,974 research outputs found
Evaluating Osteotomy Accuracy in Mandibular Reconstruction: A Preliminary Study Using Custom Cutting Guides and Virtual Reality
Full text linkBackground: Mandibular reconstruction has evolved significantly since its inception in the early 1900s. Currently, the fibula free flap (FFF) is considered the gold standard for mandibular and maxillary reconstructions, particularly for extensive defects, and the introduction of Extended Reality (XR) and virtual surgical planning (VSP) is revolutionizing maxillofacial surgery. Methods: This study focuses on evaluating the accuracy of using in-house cutting guides for mandibular reconstruction with FFF supported by virtual surgical planning (VSP). Planned and intraoperative osteotomies obtained from postoperative CT scans were compared in 17 patients who met the inclusion criteria. The proposed analysis included measurements of deviation angles, thickness at the centre of gravity, and the maximum thickness of the deviation volume. Additionally, a mandibular resection coding including 12 configurations was defined to classify and analyze the precision of mandibular osteotomies and investigate systematic errors. Preoperative, planned, and postoperative models have been inserted in an interactive VR environment, VieweR, to enhance surgical planning and outcome analysis. Results: The results proved the efficiency of adopting customized cutting guides and highlighted the critical role of advanced technologies such as CAD/CAM and VR in modern maxillofacial surgery. A novel coding system including 12 possible configurations was developed to classify and analyze the precision of mandibular osteotomies. This system considers (1) the position of the cutting blade relative to the cutting plane of the mandibular guide; (2) the position of the intersection axis between the planned and intraoperative osteotomy relative to the mandible; (3) the direction of rotation of the intraoperative osteotomy plane around the intersection axis from the upper view of the model. Conclusions: This study demonstrates the accuracy and reliability of in-house cutting guides for mandibular reconstruction using fibula free flaps (FFF) supported by virtual surgical planning (VSP). The comparison between planned and intraoperative osteotomies confirmed the precision of this approach, with minimal deviations observed. These findings highlight the critical role of CAD/CAM and XR technologies in modern maxillofacial surgery, offering improved surgical precision and optimizing patient outcomes
Head and neck soft tissue reconstruction with anterolateral thigh flaps with various components: development of an algorithm for flap selection in different clinical scenarios
No full textObjectives: The antero-lateral thigh free flap (ALT) is conventionally designed as a fasciocutaneous flap (FALT). However, the thickness of the flap can be designed in at least in two more variants: myocutaneous (MYALT), and myofascial (MALT). The aim of this study was to evaluate the use of ALT flap as a universal solution for head and neck soft tissue reconstruction and development of an algorithm for flap selection in different clinical scenarios. Patients and methods: Forty patients, 29 males, 11 females, with mean age of 61.6 years (range 36–77) were enrolled. Thirty-three patients were affected by mucosal squamous cell carcinoma (24 oral cavity, 8 larynx, 1 hypopharynx), four by cutaneous squamous cell carcinoma, two by sarcoma of the orbit, one by adenoid cystic carcinoma of the parotid gland. MALT was used for tongue reconstructions thicker than 2 cm. When vastus lateralis was not thick enough we used MYALT, which was used for bulky head and neck reconstruction requiring mucosa and/or skin. FALT was performed for oral and mucosal defects thinner than 2 cm. We performed 19 MYALT, 11 FALT, and 10 MALT. We proposed ALT reconstruction to all patients requiring soft tissue replacement, for this reason selection bias is excluded. Statistical analysis was conducted to analyze any difference in defect size, flap volume, functional, and cosmetic results. Results: Overall mean follow-up was 18.9 months (range 3–48). Follow-up of single flaps was as follow: MALT 20.3 (range 3–48), MYALT 17.6 (range 4–45), FALT 19.1 (range 3–48), mean time of follow-up was not significant among the three groups (p.82). Mean size of the defect in cm3 was 188.5 (range 25–495), Mean sizes of the defects were: tongue 177.7 (range 48–360), oral floor/check 128.3 (range 25–432), larynx hypopharynx 315.7 (range 184–495), and maxilla 232.0 (range 224–240). Mean volume difference was significantly different between oral floor defects and larynx/hypopharynx (mean volume difference 187.4 95% CI −352.0—2.7 p <.001). Mean sizes of the flaps in cm3 were: FALT 51.5 (range 25–72), MYALT 270.7 (range 90–495), and MALT 250.0 (range 90–495). Mean volume difference was significantly different among the three groups (p <.001). No major complications were experienced, four minor complications were reported (2/19 in MYALT, 1/10 MALT, 1/10 FALT) and results were not significant among the three groups (p.20). Gastrostomy tube dependence occurred in 4/19 (21%) of tongue cases, and none in all the other cases (p <.001). Speech was unintelligible in 3/19 (16%) of patients with tongue reconstruction, 1/7 (15%) of patients with larynx/hypopharynx reconstruction, and none regarding the other defects reconstructed (p <.001). Cosmesis was poor in 2/19 (11%) of tongue cases, and acceptable or higher in the other cases (p <.001). Tracheostomy dependence rate was 27% (7/7 patients submitted to a total laryngectomy with hypopharyngectomy and 4/19 patients submitted to total glossectomy, p <.001). Conclusions: ALT offers unique advantages in head and neck reconstruction, including adequate bulk when needed, different coating surfaces, and optimal functional results with minimal morbidity. On the base of our case series, which showed that the ALT flap is highly versatile and a successful reconstructive option, we propose a decision making-flow chart in order to choose the best specific flap variant adequate for every specific clinical scenario
Myomucosal island flap in the reconstruction of oral cavity defects: Description of the surgical technique
Full text linkMultiple options are available for the reconstruction of the defects of the oral cavity. Among these, the facial artery myomucosal island flap (FAMMIF) is a pedicled flap composed by cheek mucosa, submucosa, and part of the buccinator muscle. The FAMMIF is ideal for the reconstruction of small-to-moderate defects of the oral cavity and the oropharynx. This is due to low operating time, low morbidity, and good functional and aesthetic results. A step-by-step description of the flap harvesting is presented, with particular attention to flap design, identification of the vessels, harvesting of the myomucosal island, tunnel preparation for its passage in the neck and back to the oral cavity, and closure of the cheek donor site with the buccal fat pad
Antibiotic prophylaxis in head and neck cancer surgery: Systematic review and Bayesian network meta-analysis
No full textPostoperative surgical site infections (SSI) are worrisome complications after head and neck cancer surgery. Due to the lack of direct comparisons, it is difficult to indicate the best antibiotic in the setting of SSI prophylaxis for patients with head and neck cancer. For this reason, we decided to conduct a Bayesian network meta-analysis of clinical studies evaluating various antibiotic classes for SSI prophylaxis; thus, we directly and indirectly compared all the available antibiotics in the setting of head and neck oncological surgery. We performed a systematic review and a network meta-analysis according to the PRISMA-NMA checklist. Regarding inclusion criteria, we included articles with retrospective or prospective design recruiting adult participants with head and neck neoplasm of any subsite that compared different antibiotics or that compared different antibiotic treatment duration with sample sizes of more than 10 patients. Overall, 310 citations were identified by the search on all databases. Of these, 250 were excluded based on title and abstract, leaving 60 publications for full text examination. Finally, 20 papers were included for data extraction and analysis. In total, 8627 patients were evaluated across the included studies. Results of the Bayesian network meta-analysis showed that when compared to clindamycin short course, the antibiotics effective in preventing SSI were ampicillin/sulbactam or other penicillin short course (OR: 0.37, 95%CrI: 0.19–0.72), cefazolin/metronidazole short course (OR: 0.26, 95%CrI: 0.06–0.93), cefazolin (OR: 0.36, 95%CrI: 0.17–0.79), ampicillin/sulbactam long course (OR: 0.20, 95%CrI: 0.04–0.91), cefazolin/metronidazole long course (OR: 0.27, 95%CrI: 0.09–0.64), cefoperazone (OR: 0.05, 95%CrI: 0.002–0.89), cefotaxime (OR: 0.04, 95%CrI: 0.002–0.85). There was no significant difference between clindamycin and no antibiotic (OR: 2.3, 95%CrI: 0.59–9.9). Clindamycin plus aminoglycoside seemed to give a slight protection from SSI compared to clindamycin alone (OR: 0.30, 95%CrI: 0.09–0.99) or no antibiotic (OR: 0.13, 95%CrI: 0.02–067). Antibiotic prophylaxis is important in preventing SSI in head and neck cancer setting. Current evidence suggests that penicillins and cephalosporins are the best choice. Moreover, long duration course does not give any advantage compared to short course prophylaxis. Finally, it is important to implement appropriate antibiotic prophylaxis in patients that are labeled as penicillin allergic, in this regard clindamycin seems to be ineffective and, for this reason, further research is needed to provide a better care for this subset of patients
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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