Tire Slip H∞ Control for Optimal Braking Depending on Road Condition.

Tire slip control is one of the most critical topics in vehicle dynamics control, being the basis of systems such the Anti-lock Braking System (ABS), Traction Control System (TCS) or Electronic Stability Program (ESP). The highly nonlinear behavior of tire-road contact makes it challenging to design robust controllers able to find a dynamic stable solution in different working conditions. Furthermore, road conditions greatly affect the braking performance of vehicles, being lower on slippery roads than on roads with a high tire friction coefficient. For this reason, by knowing the value of this coefficient, it is possible to change the slip ratio tracking reference of the tires in order to obtain the optimal braking performance. In this paper, an H∞ controller is proposed to deal with the tire slip control problem and maximize the braking forces depending on the road condition. Simulations are carried out in the vehicular dynamics simulator software CarSim. The proposed controller is able to make the tire slip follow a given reference based on the friction coefficient for the different tested road conditions, resulting in a small reference error and good transient response.

¿Es posible obtener información de la presión intracraneal a partir de la actividad electroencefalográfica? / Is it possible to extract intracranial pressure information based on the EEG activity?

Introducción. El electroencefalograma (EEG) permite obtener información directa de la actividad bioeléctrica del cerebro y es una herramienta fundamental para la evaluación de la condición neurológica del paciente. En los últimos años ha comenzado a emplearse también para obtener indirectamente información sobre la hemodinámica cerebral y las variables que intervienen en la autorregulación del flujo sanguíneo cerebral. Objetivo. Estudiar la posible relación entre la actividad electroencefalográfica y la presión intracraneal (PIC) en pacientes con traumatismo craneoencefálico y hemorragia subaracnoidea ingresados en cuidados intensivos. Pacientes y métodos. Se incluyó a 21 pacientes (10 mujeres) mayores de 18 años con traumatismo craneoencefálico o hemorragia subaracnoidea que requerían monitorización de la PIC y a los que se les registró el EEG de forma continua. Se determinó la causalidad de Granger entre la PIC con respecto a las variables espectrales del EEG para ventanas temporales de 10 minutos durante la estancia en cuidados intensivos. Resultados. La causalidad de Granger mostró una alta correlación entre la PIC con las bandas del EEG. En la mayoría de los pacientes existe una causalidad de Granger significativa en la dirección del EEG hacia la PIC en gran parte del tiempo de monitorización, de forma que las variables del EEG precedían a la PIC. Conclusiones. El presente trabajo expone la relación temporal subyacente entre la dinámica de la PIC y la actividad bioeléctrica cerebral registrada mediante EEG en pacientes con traumatismo craneoencefálico y hemorragia subaracnoidea. El potencial uso de esta relación podría permitir estimar la PIC de manera no invasiva

Introduction. The capability of the electroencephalography (EEG) of recording the bioelectrical activity of the brain has made of it a fundamental tool for the evaluation of the patient’s neurological condition. In recent years, moreover, it has also begun to be used in obtaining information for other kind of variables, as the ones related with the cerebral hemodynamics Aim. To study the potential relationship between the EEG activity and the intracranial pressure (ICP) in patients suffering from traumatic brain injury and subarachnoid hemorrhage, during their stay at the intensive care unit. Patients and methods. Twenty-one adult patients (10 women) were included in the present observational prospective cohort study. They suffered from either traumatic brain injury or subarachnoid hemorrhage, requiring continuous EEG and ICP monitoring. In every patient, Granger causality between spectral functions of the EEG and the ICP was evaluated. Temporal windows of 10 minute were used to evaluate whether a causal relationship between those variables exist or not. In all of the cases, several days of continuous recording and assessment were performed. Results. In most patients and during most of the time, Granger causality turns out to be significant in the direction from the EEG to the ICP, meaning that the EEG dynamics actually leads the ICP dynamics. Conclusions. The present work provides useful information and shed light in discovering a hidden relationship between the ICP and EEG dynamics. The potential use of this relationship could lead to develop a medical device to measure ICP in a non-invasive fashion

Potential EEG biomarkers of sedation doses in intensive care patients unveiled by using a machine learning approach.

OBJECTIVE: Sedation of neurocritically ill patients is one of the most challenging situation in ICUs. Quantitative knowledge on the sedation effect on brain activity in that complex scenario could help to uncover new markers for sedation assessment. Hence, we aim to evaluate the existence of changes of diverse EEG-derived measures in deeply-sedated (RASS-Richmond agitation-sedation scale -4 and -5) neurocritically ill patients, and also whether sedation doses are related with those eventual changes. APPROACH: We performed an observational prospective cohort study in the intensive care unit of the Hospital de la Princesa. Twenty-six adult patients suffered from traumatic brain injury and subarachnoid hemorrhage were included in the present study. Long-term continuous electroencephalographic (EEG) recordings (2141 h) and hourly annotated information were used to determine the relationship between intravenous sedation infusion doses and network and spectral EEG measures. To do that, two different strategies were followed: assessment of the statistical dependence between both variables using the Spearman correlation rank and by performing an automatic classification method based on a machine learning algorithm. MAIN RESULTS: More than 60% of patients presented a correlation greater than 0.5 in at least one of the calculated EEG measures with the sedation dose. The automatic classification method presented an accuracy of 84.3% in discriminating between different sedation doses. In both cases the nodes' degree was the most relevant measurement. SIGNIFICANCE: The results presented here provide evidences of brain activity changes during deep sedation linked to sedation doses. Particularly, the capability of network EEG-derived measures in discriminating between different sedation doses could be the framework for the development of accurate methods for sedation levels assessment.

Identifying causal relationships between EEG activity and intracranial pressure changes in neurocritical care patients.

OBJECTIVE: To explore and assess the relationship between electroencephalography (EEG) activity and intracranial pressure (ICP) in patients suffering from traumatic brain injury (TBI) and subarachnoid hemorrhage (SAH) during their stay in an intensive care unit. APPROACH: We performed an observational prospective cohort study of adult patients suffering from TBI or SAH. Continuous EEG-ECG was performed during ICP monitoring. In every patient, variables derived from the EEG were calculated and the Granger causality (GC) methodology was employed to assess whether, and in which direction, there is any relationship between EEG and ICP. MAIN RESULTS: One-thousand fifty-five hours of continuous multimodal monitoring were analyzed in 21 patients using the GC test. During 37.88% of the analyzed time, significant GC statistic was found in the direction from the EEG activity to the ICP, with typical lags of 25-50 s between them. When recordings were adjusted by sedation-perfusion and/or bolus-and handling, these percentages hardly changed. SIGNIFICANCE: Long-lasting, continuous and simultaneous EEG and ICP recordings from TBI and SAH patients provide highly rich and useful information, which has allowed for uncovering a strong relationship between both signals. The use of this relationship could lead to developing a medical device to measure ICP in a non-invasive way.

A shift from the osteocutaneous fibula flap to the prelaminated osteomucosal fibula flap for maxillary reconstruction.

BACKGROUND: Reconstruction of the maxilla with the fibula free flap is a popular and well-described technique. The ideal intraoral lining would be mucosa, which is moist, thin, and non-hair-bearing. Prelamination of the fibula with buccal mucosa replaces like tissue with like tissue, obviates the need for a skin paddle, and facilitates placement of osseointegrated implants in a single stage. For central maxillary defects, the authors have shifted from using an osteocutaneous to a prelaminated free fibula flap. In this article, the authors report their experience using the prelaminated osteomucosal fibula for maxillary reconstruction. METHODS: From 2003 to 2011, 24 patients underwent reconstruction of a central maxillary defect using a free fibula flap. The first 10 patients had osteoseptocutaneous flaps, and the other 14 patients had prelaminated flaps. Data collected included patient age, cause of defect, type and number of operations, complications at both the donor and recipient sites, and placement of osseointegrated implants. RESULTS: The majority of patients in the series (n = 21) had central maxillary defects caused by loss of the premaxilla during early repair of bilateral cleft lip-cleft palate. There was one flap failure in the nonprelaminated flap group and one in the prelaminated group. Repeated debulking to thin the skin paddle was required in all of the patients with osteocutaneous flaps. CONCLUSIONS: Prelamination delivers like tissue to the recipient site, obviates the need for debulking, and may reduce donor-site wound problems. To the authors' knowledge, this is the largest series of prelaminated fibulas for maxillary reconstruction in the literature. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.

Keloid skin scars: the influence of hyperbaric oxygenation on fibroblast growth and on the expression of messenger RNA for insulin like growth factor and for transforming growth factor.

Wound healing can result in the development of keloid scars that contain atypical fibroblasts and an overabundance of extracellular matrix components. Hyperbaric oxygenation (HBO) refers to exposure to pure oxygen under increased atmospheric pressure and is recognized as a valuable supplementary method of treatment for problematic wounds. The effect of HBO in the expression of insulin-like growth factor type 1 (ILGF-1) and transforming growth factor ß (TGF-ß) messenger RNAs was determined by semiquantitative RT-PCR in fibroblasts obtained from keloid scars and nonwound involved skin fibroblast from the same patient. ILGF-1 and TGF-ß are the principal mitogens during wound regeneration. We found a decrease in the growth of fibroblasts and in the expression of ILGF-1 and TGF-ß messengers in keloid and nonkeloid fibroblast after chronic exposition to hyperbaric oxygenation compared with normal oxygen partial pressure.

Reconstruction of the premaxilla: an option for mutilated bilateral clefts.

The loss of the maxilla is a severe mutilation resulting from inadequate surgery of bilateral clefts of the lip and palate. It is usually associated with palatal fistulae, collapse of the maxillary segments, and limited facial growth.Functional rehabilitation can be achieved by reconstruction of the premaxilla with osteomucosal fibula grafts. Mucosal grafts are fixed to the fibula in a preliminary stage. The composite graft is transplanted to the maxilla 10 to 12 weeks later. Osteointegrated implants are placed 3 months later.The procedure was used in 7 patients, 1 holoprosencephaly and 6 with sequelae of bilateral clefts; mean age, 17.28 years, with a follow-up of 14 to 70 months.The mucosal grafts integrated successfully to the fibula in all the patients. The osteocutaneous graft achieved a solid maxillary arch in all the patients. Normal mastication was achieved with a prosthesis fixed to the osteointegrated implants. Facial proportions were greatly improved.

Mandibular microsurgical reconstruction in patients with hemifacial microsomia.

BACKGROUND: Although hemifacial microsomia is a relatively common craniofacial malformation, there is some debate regarding the ideal treatment of severe mandibular hypoplasia. Traditionally, patients with severe mandibular deficits have been treated with iliac or costochondral bone grafts followed by distraction osteogenesis, with mixed results. The authors present their experience with the use of the fibula osteocutaneous free flap for mandibular reconstruction in severe hemifacial microsomia patients. METHODS: From 1999 to 2006, 10 patients aged 3 to 10 years (mean, 7.2 years) underwent 10 free flap reconstructions. Of the 10 patients, six were girls and four were boys. Data were collected retrospectively from the patients' records, photographs, and radiographs. The authors report the surgical technique used, complications, and long-term outcome. RESULTS: Nine of 10 flaps were successful, for a flap survival rate of 90 percent. Donor bone length was 5 to 10 cm, with a mean of 6.3 cm. Skin paddles ranged from 8 to 36 cm, with a mean size of 18.7 cm. Mean operation time was 412 minutes and mean follow-up was 45.4 months (range, 12 to 94 months). Two patients underwent successful distraction osteogenesis subsequent to their free flap mandible reconstruction. All patients demonstrated stable bony union of the free flap by physical and radiographic examination. One major complication (a failed free flap) and two minor complications were observed. CONCLUSION: The free flap is safe and effective, and should be considered as a first choice in mandibular reconstruction in severe cases of hemifacial microsomia where distraction osteogenesis is not possible.

Nasomaxillary reconstruction in Binder syndrome: bone versus cartilage grafts. A long-term intercenter comparison between Sweden and Mexico.

Maxillonasal dysplasia is characterized by a concave facial profile and a flat nose. The etiology of Binder syndrome is skeletal hypoplasia around the piriform aperture and excavations-fossae prenasales, bilaterally in the nasal floor-which are pathognomonic. There is no real shortage of the soft tissues. In 2 medical centers in Sweden and Mexico, different grafts were used for reconstruction, but the focus was similar, filling out the maxilla anterior to the nasal floor and supporting the nasal framework to normalize tip projection. The basis for this study was to compare the long-term results between bone grafts in Sweden and cartilage grafts in Mexico. Sixteen patients from both groups were available for long-term follow-up. Simplified digital analysis of anthropometric variables were performed in the short-term and long-term follow-ups. The Swedish group had primary at the mean age of 21.3 years, whereas mean follow-up period was 16.8 years later. The Mexican group had primary at the age of 13.6 years, and the follow-up period was 8.4 years. Secondary correction was necessary in 25% of the patients in the bone graft group (Sweden) and in 19% of patients in the cartilage group (Mexico). Bone grafts slightly relapsed in tip projection and remodeled to some extent in the nasolabial angle. Cartilage grafts showed stability in the tip projection quotients and resulted in a postoperative normalization of the nasolabial angle but developed a slight relapse between the short-term and long-term follow-ups. Both techniques were stable in nose tip-length ratio, and a normalization of anthropometric variables was demonstrated in all the long-term follow-ups. Both the bone and cartilage graft techniques at the 2 centers rendered the intended result of an increased and normalized angle of convexity of the face and nasal tip projection. An experience in the properties and behavior of either graft is necessary to get a long-term stable outcome.

Major craniofacial clefts: case series and treatment philosophy.

BACKGROUND: The treatment of major facial clefts has evolved greatly over the past 40 years. Early in the authors' experience, soft tissues were treated by Z-plasty and local flap rotation, resulting in a patchwork effect and noticeable scars. Bony deficits were treated with bone grafts that often failed to restore normal facial contour. In 1985, the authors developed a treatment philosophy to resolve these issues, and its tenets have formed the foundation of treatment since then. METHODS: From January of 1965 to January of 2006, a series of 495 patients with major craniofacial clefts were treated in the authors' unit. Sixty-five percent had multiple clefts and 35 percent had a single cleft. In 33 percent of patients, the clefts were unilateral and in 67 percent the clefts were bilateral. The objectives of the authors' current treatment philosophy are restoration of the craniofacial skeleton, reconstruction with skin and soft tissue of like color and texture, generous use of tissue expanders, aesthetic unit reconstruction, scar location at limits of aesthetic subunits, and symmetric repositioning of key facial landmarks. RESULTS: Patients underwent a total of 1338 operations. Follow-up ranged from 8 months to 35 years. All patients who underwent primary reconstruction after 1985 underwent successful reconstruction using the aesthetic subunit principle. Fifty-three percent of patients required formal craniofacial osteotomy and 24 percent required bone grafting to restore the craniofacial skeleton. CONCLUSIONS: The authors' results have improved considerably both in primary and in secondary reconstruction by incorporating their revised treatment philosophy. The authors have reduced scar visibility and facial asymmetry, allowing these patients to live more normal lives.

The art of moving the orbits.

In ancient times, important events were commemorated in works of art produced by outstanding painters and sculptors. This custom included medical advancements such as The Anatomic Lesson painted by Rembrandt and the Public Demonstration of Anesthesia with Ether, in Boston, painted by Robert Hinchlay. The advent of inexpensive photographic recording eliminated the need to commission artists to preserve an event for posterity. One of the landmarks of medicine in the twentieth century is craniofacial surgery, developed by Tessier. The personal interest and relationship of the author with a prominent artist presented the opportunity to record in paintings the outstanding contribution of the remarkable French surgeon. A series of 10 canvases inspired by craniofacial surgery are discussed in this article.

Swallowing disorders in Pierre Robin sequence: its correction by distraction.

Pierre Robin sequence is characterized by micro-gnathia, glossoptosis, feeding difficulties, and upper respiratory obstruction, which are frequently complicated by bronchial aspiration and pulmonary infection. Gastroesophageal reflux is also common in these patients. To assess the results of mandibular distraction, a study was performed in 18 patients to detect swallowing disorders associated with apnea episodes and gastroesophageal reflux. Polysomnography, barium pharyngoscopy, determination of blood gases, and esophageal pH measurements were undertaken before and 4 months after distraction osteogenesis. Bilateral corticotomies, followed by distraction with external devices, were performed, achieving 7 to 19 mm of elongation (mean = 12 mm). Gastroesophageal reflux was found in 83% of cases associated with apnea episodes, but it disappeared after distraction osteogenesis. Mean preoperative oxygen saturation was 72%, and it was 93% afterward. The preoperative apnea index was 18.3, and the preoperative 8.5 hypopnea index was 8.5; both disappeared. Pharyngeal transit time became less than 1 second after treatment. Abnormal tongue movements and barium stasis in the pharyngeal recess and in the trachea were eliminated in all the patients.

The dawn of plastic surgery in Mexico: XVIth century.

An aspect of early Mexican surgery in the sixteenth century is presented. The treatment of facial wounds by Alonso Lopez de Hinojosos and Agustin Farfán is reviewed. Farfán proposed total nose reconstruction, with a cutaneous arm flap, 18 years before its description in De Curtorum Chirurgia, by Tagliacozzi, in 1597 in Venice, Italy. The chapter on facial wounds by Lopez de Hinojosos and Farfán shows their concern for the final aesthetic results and should be considered the first Mexican publication in the field of plastic surgery.

Distraction osteogenesis in Pierre Robin sequence and related respiratory problems in children.

INTRODUCTION: Sleep apnea is one of the most frequent manifestations of respiratory obstruction. Historically this clinical entity has stimulated the production of numerous valuable contributions with one purpose in mind: the improvement of airway permeability. A multi-disciplinary approach is required to define the problem in anatomic and functional terms to avoid a tracheostomy and prevent long-term sequels. We decided on an approach that focuses on improving the projection of the tongue in the posterior pharynx; by lengthening the mandible and bringing the muscular insertions of the floor of the mouth forward, the antero-posterior dimensions of the airway are increased. OBJECTIVE: To evaluate mandibular distraction osteogenesis as a simple mandibular lengthening procedure useful as a definite treatment in patients with obstructive sleep apnea. MATERIAL AND METHODS: The series consisted of 15 consecutive patients, divided in four groups. Patients with acute upper airway obstruction who required endotracheal intubation, patients with no acute upper airway obstruction but with severe respiratory distress, patients with milder degrees of airway obstruction, and patients with long-term tracheostomies. Therapeutic interventions were performed according to the findings of each group. RESULTS: The patients were evaluated according to cephalometric analysis, polysomnograms, nasopharyngoscopy, and clinical data. Significant changes were seen in the cephalometric studies. There were no postoperative episodes of apnea; clinical improvement occurred in all patients and decannulation was possible in all patients. CONCLUSION: Mandibular distraction is a safe and reliable procedure for treating patients with obstructive sleep apnea.

Hemangioma and bilateral cleft lip / Hemangioma y labio hendido bilateral

Introducción. De los tumores pediátricos los hemangiomas son los más comunes y frecuentemente se localizan en las regiones de cabeza y cuello. Rara vez están asociados a síndrome dismórficos. En este reporte se presenta a una niña con un hemangioma y labio hendido bilateral; se revisan las teorías acerca de la embriogénesis del labio hendido y el posible origen de estos hallazgos clínicos. Caso clínico. Paciente del sexo femenino de 15 meses de edad con labio hendido complejo bilateral y un hemangioma localizado en el prolabio, en ambos segmentos laterales, nariz, mejilla y ceja superior izquierda; el paladar y el reborde alveolar estaban normales. La primera evidencia de la proliferación de la lesión apareció sobre el prolabio al poco tiempo del nacimiento. No se le apreciaban otras malformaciones. La extensión del tumor sobre la nariz mostró crecimiento a las 2 semanas de edad. A las 4 semanas, la lesión era evidente sobre los segmentos laterales del labio superior, mejilla izquierda, y ceja superior izquierda. Los estudios radiológicos, que incluían tomografía computada de cabeza y cuello, no mostraron evidencia de compromiso de huesos subyacentes o de otras estructuras vitales. El plan de tratamiento incluyó una reparación en línea recta de la hendidura bilateral y resección parcial del hemangioma. Se incluyen también los resultados postoperatorios. Conclusión. La correlación temprana de la fisura puede ser un tratamiento opcional en un niño que además de labio hendido tiene un hemangioma localizado, contrario a la reparación tardía acostumbrada

Recovery of congenital facial palsy in patients with hemifacial microsomia subjected to sural to facial nerve grafts is enhanced by electric field stimulation

The effect of electric field stimulation for promoting axonal growth between sural to facial nerve graft in cases of congenital permanent facial palsy associated with hemifacial microsomia was studied pre- and postoperatively. A sural to facial nerve graft was performed in all cases and long term postoperative electric field stimulation was randomly applied to half to the patients. Although improvement occurred in both groups, the results indicated that clinical and elctrophysiological recovery was significantly better in patients receiving post-operative electric field stimulation. The results, therefore, suggest that electric stimulation of the grafted area induces improvements of facial palsy over and above those observed in the non-stimulated patients

Tumores da parede torácica: experiência do Instituto Nacional de Câncer / Chest wall tumors: experience at the Instituto Nacional de Câncer - Rio de Janeiro, Brazil

Trinta e quatro pacientes portadores de tumor de parede torácica tratados no Instituto Nacional de Câncer, no período de janeiro de 1980 a dezembro de 1986, foram analisados retrospectivamente. Vinte tumores se originaram do arcabouço ósseo e 15 das partes moles (um paciente apresentou dois tumores separados). Deste total 23 eram malignos e distribuidos da seguinte maneira: 47,8% (11/23) nas partes moles e 52,2%) com histologia maligna tiveram queixas por no máximo cinco meses. O diagnóstico histopatológico mais comum foi sarcoma. O esterno estava comprometido pelo tumor em seis casos. Foram feitas nove ressecçöes osteocarilaginosas, 13 toracectomias, quatro ressecçöes parciais do esterno, nove ressecçöes de partes moles e biopsia da lesäo em dois casos. Nos pacientes submetidos a ressecçöes extensas a reconstruçäo plástica foi efetuada imediatamente. A mortalidade cirúrgica foi de 2,9% (1/34). O seguimento mínimo foi de seis meses. O controle local foi conseguido em 88% dos casos. Concluímos que a ressecçäo cirúrgica associada as novas técnicas de reconstruçäo é possivel e oferece excelentes índices de controle local dos tumores dessa regiäo