Tracheal reconstruction: mini-review and anatomical study on the use of antero lateral thigh fascial flap for heterotopical transplantation

Background: The reconstructive tracheal options for extensive lesions still remain limited and although a valid substitute is required unfortunately, the biomechanical tracheal characteristics do not allow an easy replacement. In this study we reviewed the described options and investigated, in human cadaver model, whether thigh fascia can be used, as an alternative to forearm fascia, as recipient site for trachea graft heterotopical allotransplantation. Anatomical study: In three fresh cadavers, 3 tracheal graft, 6 radial forearm (RF) fascial flaps and 6 antero-lateral thigh (ALT) fascial flaps were harvested. For each flap we simulated the heteretopical transplantation of the trachea in each fascial flap, and the harvesting of the composite graft as a free flap. The composite graft was finally decomposed at bench and the pedicle was injected to confirm fascial vascularization. The main measured outcomes were: flap fascia vascularization after pedicle injection, average time of flap harvesting, number of perforators included in ALT fascial flap and diameter of the vessels for anastomosis. Difficulties were noted, in order to compare RF flap and ALT flap. Results: Fascia vascularization was confirmed in all cases by pedicle injection. The main difficulty with radial flap was to harvest the fascial layer due to its thinness and its strong adherence to palmaris longus tendon, while the main difficulty with ALT flap was to prevent any traction on the perforators. The average time of flap harvesting and graft inset (by a junior plastic surgeon) was 1 h and 30 min for radial forearm flap and 2 h and 10 min for ALT flap. Conclusion: Despite many different techniques proposed in the literature, tracheal heterotopical allotransplantation still seemed the most promising, and ALT flap promised be a feasible alternative for heterotopical transplantation of trachea

Long-term subjective outcomes of barbed reposition pharyngoplasty for obstructive sleep apnea syndrome treatment

Background: The purpose of this study was to evaluate long-term subjective outcomes of barbed reposition pharyngoplasty for obstructive sleep apnea syndrome (OSAS) treatment using a specific questionnaire, the Palate Postoperative Problem Score (PPOPS). Methods: 140 patients who underwent barbed reposition pharyngoplasty (BRP) surgery in the Morgagni Pierantoni Hospital of Forlì, Italy were enrolled in the study. Postoperative outcomes were evaluated in a short- and long-term follow-up using the PPOPS questionnaire. The average period of follow-up was 26 months. All patients received the PPOPS questionnaire by telephone in a period between April and August 2019. Results: 51% of patients complained of swallowing problems after surgery. In 91% of cases, the problem cleared up spontaneously. At the time of the interview, only 9% of patients had a residual swallowing difficult. At the time of PPOPS evaluation, rhinolalia was observed in 8% of patients, whereas nose regurgitation was present in 2% of patients. In 20% of patients, the foreign body sensation was present during follow-up. The value of apnea-hypopnea index (AHI) reduced from the preoperative value of 31.5 to the postoperative value of 11.4. Conclusions: BRP surgery proved to be an effective technique, appreciated by the majority of patients. Use of the PPOPS questionnaire has demonstrated that the BRP technique seems to ensure efficacy and lower morbidity, with few complications after surgery

Risk factors for obstructive sleep apnea syndrome in children: state of the art

The obstructive sleep apnea syndrome (OSAS) represents only part of a large group of pathologies of variable entity called respiratory sleep disorders (RSD) which include simple snoring and increased upper airway resistance syndrome (UARS). Although the etiopathogenesis of adult OSAS is well known, many aspects of this syndrome in children are still debated. Its prevalence is about 2% in children from 2 to 8 years of age, mostly related to the size of the upper airways adenoid tissue. Several risk factors linked to the development of OSAS are typical of the pediatric age. The object of this paper is to analyze the state of the art on this specific topic, discussing its implications in terms of diagnosis and management

Long‐term subjective outcomes of barbed reposition pharyngoplasty for obstructive sleep apnea syndrome treatment

Background: The purpose of this study was to evaluate long‐term subjective outcomes of barbed reposition pharyngoplasty for obstructive sleep apnea syndrome (OSAS) treatment using a specific questionnaire, the Palate Postoperative Problem Score (PPOPS). Methods: 140 patients who underwent barbed reposition pharyngoplasty (BRP) surgery in the Morgagni Pierantoni Hospital of Forlì, Italy were enrolled in the study. Postoperative outcomes were evaluated in a short‐ and long‐term follow‐up using the PPOPS questionnaire. The average period of follow‐up was 26 months. All patients received the PPOPS questionnaire by telephone in a period between April and August 2019. Results: 51% of patients complained of swallowing problems after surgery. In 91% of cases, the problem cleared up spontaneously. At the time of the interview, only 9% of patients had a residual swallowing difficult. At the time of PPOPS evaluation, rhinolalia was observed in 8% of patients, whereas nose regurgitation was present in 2% of patients. In 20% of patients, the foreign body sensation was present during follow‐up. The value of apnea−hypopnea index (AHI) reduced from the preoperative value of 31.5 to the postoperative value of 11.4. Conclusions: BRP surgery proved to be an effective technique, appreciated by the majority of patients. Use of the PPOPS questionnaire has demonstrated that the BRP technique seems to ensure efficacy and lower morbidity, with few complications after surgery

Trans-oral robotic surgery for the management of oropharyngeal carcinomas: A 9-year institutional experience

Trans-oral robotic surgery (TORS) has changed surgical management of patients with oropharyngeal squamous cell carcinomas (OPSCC). In this study we present surgical and oncologic outcomes of patients with oropharyngeal squamous cell carcinomas, treated using TORS, with and without an adjuvant therapy. Sixty patients with oropharyngeal squamous cell carcinomas treated with TORS between January 2008 and December 2017 have been retrospectively evaluated considering clinicopathologic features, disease characteristics, adjuvant treatments and oncological outcomes. TORS was performed for OPSCC to the base of tongue in 41.7%, tonsils in 46.7%, soft palate and posterior pharyngeal wall in 3.3% and 5%, respectively. Neck dissection was performed in 43.3% of patients. Management strategies included surgery alone in 30%, TORS and adjuvant radiotherapy in 33.3%, and TORS plus adjuvant chemotherapy in 36.7%. The 5-year overall survival of the total group was 77.6%, the 5-year disease-free survival rate was 85.2%, and the 5-year local recurrence-free survival rate was 90.6%. Finally, in selected patients TORS appears to yield similar oncologic outcomes and functional outcomes to traditional techniques and non-operative treatment with a possible benefit on long-term quality of life. The future offers exciting opportunities to combine TORS and radiotherapy in unique ways. However, further research is urgently needed to clarify the indications for adjuvant therapy following TORS resections

Revisiting special relativity: A natural algebraic alternative to Minkowski spacetime

Minkowski famously introduced the concept of a space-time continuum in 1908, merging the three dimensions of space with an imaginary time dimension $i c t$, with the unit imaginary producing the correct spacetime distance $x^2 - c^2 t^2$, and the results of Einstein's then recently developed theory of special relativity, thus providing an explanation for Einstein's theory in terms of the structure of space and time. As an alternative to a planar Minkowski space-time of two space dimensions and one time dimension, we replace the unit imaginary $i = \sqrt{-1}$, with the Clifford bivector $\iota = e_1 e_2$ for the plane that also squares to minus one, but which can be included without the addition of an extra dimension, as it is an integral part of the real Cartesian plane with the orthonormal basis $e_1$ and $e_2$. We find that with this model of planar spacetime, using a two-dimensional Clifford multivector, the spacetime metric and the Lorentz transformations follow immediately as properties of the algebra. This also leads to momentum and energy being represented as components of a multivector and we give a new efficient derivation of Compton's scattering formula, and a simple formulation of Dirac's and Maxwell's equations. Based on the mathematical structure of the multivector, we produce a semi-classical model of massive particles, which can then be viewed as the origin of the Minkowski spacetime structure and thus a deeper explanation for relativistic effects. We also find a new perspective on the nature of time, which is now given a precise mathematical definition as the bivector of the plane.Comment: 29 pages, 2 figure

pi-pi scattering in a QCD based model field theory

A model field theory, in which the interaction between quarks is mediated by dressed vector boson exchange, is used to analyse the pionic sector of QCD. It is shown that this model, which incorporates dynamical chiral symmetry breaking, asymptotic freedom and quark confinement, allows one to calculate $f_\pi$, $m_\pi$, $r_\pi$ and the partial wave amplitudes in $\pi$-$\pi$ scattering and obtain good agreement with the experimental data, with the latter being well described up to energies \mbox{$E\simeq 700$ MeV}.Comment: 23 Pages, 4 figures in PostScript format, PHY-7512-TH-93, REVTEX Available via anonymous ftp in /pub: login anonymou get pipi93.tex Fig1.ps Fig2.ps Fig3.ps Fig4.p

Acquired nasopharyngeal stenosis correction using a modified palatal flaps technique in obstructive sleep apnea (OSA) patients

Background: Acquired nasopharyngeal stenosis is a rare and heterogeneous pathological condition that has different causes, generally resulting as a complication of a pharyngeal surgery, especially in patients affected by obstructive sleep apnea (OSA). Different approaches have been proposed for the treatment of nasopharyngeal stenosis but a unique and standardized management has not yet been presented. The aim of our paper is to evaluate the efficacy of our surgical technique, describing its steps and results with the aim to consider it as a possible solution for the treatment of this condition. Methods: This is a retrospective cohort study. Eight patients (mean age 27.25 years old (yo), range 8–67 yo; Male/Female ratio 4/4; mean body mass index (BMI) 26.1) affected by OSA (mean apnea hypopnea index (AHI) before OSA surgery was 22.1) and acquired nasopharyngeal stenosis as a consequence of different pharyngeal surgeries were treated with our modified approach in the Department of Otolaryngology, Morgagni Pierantoni Hospital, Forlì, Italy. Resolution of stenosis and complication rate were the main outcome measures. Results: Complete resolution of the stenosis was achieved in all cases and no complications were recorded at three weeks, six months, and 2 years follow-up. Conclusions: Our technique appears to be a promising method for the management of nasopharyngeal stenosis in OSA patients. However, further studies comparing different techniques and reporting on larger series and longer follow up time are needed to prove the efficacy of the proposed technique

Computational modeling with spiking neural networks

This chapter reviews recent developments in the area of spiking neural networks (SNN) and summarizes the main contributions to this research field. We give background information about the functioning of biological neurons, discuss the most important mathematical neural models along with neural encoding techniques, learning algorithms, and applications of spiking neurons. As a specific application, the functioning of the evolving spiking neural network (eSNN) classification method is presented in detail and the principles of numerous eSNN based applications are highlighted and discussed