Histomorphologic, Biomechanical, and Functional Analysis in Mandibular Osteogenesis Induced by External Distraction.

The induced bone generation procedure (osteogenic distraction [OD]) is frequently used in cases of jaw deformities in patients with, hemifacial microsomia, mandibular hypoplasia, and so on. This study was undertaken to provide criteria to perform this procedure. The authors evaluated the effects of various parameters using OD to determine the optimal variables. Sixty distractors were placed in 30 canine subjects who then underwent OD after appropriate osteotomy. The procedures were performed during varying latency periods, distraction periods, distraction rate distance, and the consolidation period. Bone biopsies and radiographic studies were performed at 0, 7, 14, 21, 45, and 55 days after the distraction process. The observed changes and the most efficient mandibular OD parameters are reported.

Determinación de los parámetros idóneos de la distracción osteogénica de la mandíbula. Estudio experimental / Determination of mandibular distraction osteogenesis most suitable parameters. An experimental study

Resumen Antecedentes: Respecto a la distracción osteogénica (generación ósea inducida), con mayor o menor éxito han sido descritos diversos protocolos para el manejo del período de latencia, velocidad de distracción y período de consolidación. Objetivo: Entender mejor el proceso de la distracción mandibular y establecer los factores determinantes y sus tiempos óptimos. Material y métodos: Se estudiaron 27 perros sometidos a distracción osteogénica unidireccional, bilateral de la mandíbula. Los procesos de distracción se aplicaron con seis variantes, dos por cada factor (período de latencia, período de distracción y velocidad de distracción). Se estudiaron los cambios mediante biopsias del hueso y radiografías de la zona a los 0, 7, 14, 21, 45 y 55 días del proceso. Resultados: Los parámetros de distracción osteogénica más eficientes fueron período de latencia de cinco días, período de consolidación de seis semanas, 1 mm diario de velocidad de distracción para distancias menores a 20 mm y 3 mm diarios para distancias mayores. Conclusiones: El estudio histológico secuencial permitió observar la aparición de los elementos celulares (osteocitos, osteoclastos, matriz osteoide, trabeculado, etcétera) y su participación en el tejido de granulación, el hueso neoformado y el hueso maduro compacto.

Abstract Background: Distraction osteogenesis is a process of induced bone generation. Various protocols have been described for the management of the latency period, distraction speed and consolidation period, with greater or lesser success. Objective: To better understand the process of mandibular distraction and establish the determining factors and their optimal times. Material and methods: Twenty-seven dogs were studied, which had 54 distractors placed and that underwent unidirectional, bilateral mandibular distraction osteogenesis. The distraction processes were applied using six variants, two for each factor: latency period, distraction period and distraction speed. The changes were examined by means of bone biopsies and X-rays of the area at 0, 7, 14, 21, 45 and 55 days of the process. Results: The most efficient osteogenic distraction parameters were a latency period of five days, a consolidation period of six weeks, distraction speed of 1 mm/day for distances of less than 20 mm, and 3 mm/day for longer distances. Conclusions: The sequential histological study allowed to observe the appearance of cellular elements (osteocytes, osteoclasts, osteoid matrix, trabeculate, etc.) and their participation in granulation tissue, newly-formed bone and compact mature bone.

Three-Flap Mastopexy with Reduction or Augmentation.

BACKGROUND: Many authors have studied breast ptosis and made contributions to the search for a procedure that allows its correction with long-lasting results and minimal scars. Collective evolution has allowed us to reach the point where we are today and will allow us to continue improving techniques in the future. OBJECTIVES: The mastopexy procedure that we have used for the last 11 years, resulting from our surgical practice and countless observations at conferences, is a versatile procedure, applicable to different types of breasts and mastopexies with and without reduction or augmentation. METHODS: Analysis and the clinical review of the patients and the records of the mastopexy cases that we operated on using the technique from January 2009 to March, 2020, are presented here. Using a periareolar approach for grade I ptosis and an inverted "T" approach for more severe ptosis, the excess skin is removed, and three flaps of breast tissue, superior, medial and lateral, are carved. A retromammary dissection is performed to anchor the end of the flaps, medial and lateral, to the pectoral aponeurosis, followed by invagination of these flaps to concentrate the breast tissue in the upper and central area of the breast. Closure of the wound is then performed, transforming its excess length into a short horizontal one, into the inframammary grove. RESULTS: Sixty-seven female patients, between 36 and 59 years old, underwent this procedure. Complications included hematoma (4%), overcorrection (4%), dehiscence (3.3%), residual ptosis (2.7%), pathological scarring (2.7%) and rotation folds (2%). Maximum follow-up was 8 years 2 months, mean follow-up 2 years 9 months, with satisfactory results for the patients and surgeon. CONCLUSIONS: The mastopexy procedure that we present here is a versatile technique, which can be applied to most cases requiring correction of ptosis. It provides the breast with proper shape, size and location with fewer scars. It is a logical, safe, efficient, reproducible procedure, which is easy to learn. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.

Efectos del ultrasonido externo sobre el panículo adiposo. Modelo porcino experimental / Effects of external ultrasound on the adipose panicle. Experimental pig model

INTRODUCCIÓN Y OBJETIVO: El ultrasonido (US) externo o percutáneo, ampliamente utilizado, ocasiona diferentes efectos histológicos dependiendo de la frecuencia, intensidad, amplitud de onda, tiempo de aplicación y de los tejidos a través de los cuales curse. Se ha utilizado con diferentes propósitos, entre otros para facilitar la liposucción y mejorar sus resultados; sin embargo, hasta donde hemos podido revisar, no hay reportes que relacionen las frecuencias del US percutáneo y el lapso de su aplicación con los cambios descritos en el panículo adiposo. El objetivo del presente estudio es establecer parámetros de frecuencia y tiempos de aplicación del US externo para uniformar criterios en base al análisis histológico de los cambios que ocasiona al panículo adiposo y a los adipocitos. MATERIAL Y MÉTODO: Estudio descriptivo, comparativo, abierto, experimental, prospectivo y longitudinal, en 59 fragmentos de tejido adiposo tomados de cerdos adultos. Cinco fragmentos fueron preservados como control; los 54 restantes fueron sometidos a US directo sobre cada fragmento, con diferentes parámetros de tiempo (5, 10 y 15 minutos) y diferentes frecuencias (baja- 1.1 Hz, media- 2.4 Hz y alta- 3.9 Hz). Fueron procesados en 2 formas (parafina y congelación) y teñidos con 2 técnicas (hematoxilina/eosina y rojo oleoso). En cada laminilla se observaron 10 campos. RESULTADOS: En los fragmentos de control observamos tejido adiposo maduro normal. En los sometidos a US, dependiendo de la frecuencia y el tiempo aplicado, observamos edema intersticial, desarreglo de su arquitectura, lisis de la membrana de los adipocitos e infiltrado inflamatorio, en diversos porcentajes, que calificamos en grados. Así en los fragmentos expuestos durante 5 minutos a frecuencia media hubo lisis leve (10%), igual que en los expuestos 10 minutos a frecuencia baja. En los expuestos 10 minutos a frecuencia media la lisis fue de leve a moderada (10-20%), semejante a la observada con frecuencia baja durante 15 minutos. Aplicando US durante 15 minutos con frecuencia baja la respuesta fue de leve a moderada (10-20%), con frecuencia media fue de moderada a severa (20-30%) y con frecuencia alta fue francamente severa (30%). CONCLUSIONES: La aplicación de US externo ocasiona lisis de los adipocitos y evidentes desarreglos en la arquitectura del tejido adiposo. Aplicarlo con frecuencias menores requiere periodos más largos para lograr los mismos efectos. Con frecuencias mayores se logran los cambios en menos tiempo. El empleo de frecuencias de 2.4 a 3.9 Hz ocasiona cambios evidentes, con amplio margen de seguridad

BACKGROUND AND OBJECTIVE: External or percutaneous ultrasound (US) widely used, causes different histological effects depending on the frequency, intensity, wave amplitude, application time and the tissues through which it passes. It has been used for different purposes, among others, to facilitate liposuction and improve its results; however, as far as we have been able to review, there are no reports that relate the frequencies of the percutaneous US and the period of its application with the changes described in the adipose tissue. Our aim is to establish frequency parameters and application times of the external US to standardize criteria, based on the histological analysis of the changes it causes to the adipose panniculus and to the adipocytes. METHODS: A descriptive, comparative, open, experimental, prospective and longitudinal study was carried out in 59 fragments of adipose tissue taken from adult pigs. Fifty-four were subjected to US applied directly to each fragment, with different time parameters (5, 10 and 15 minutes) and different frequencies (low-1.1 Hz, medium-2.4 Hz and high-3.9 Hz). Five fragments were preserved as a control. Processed in 2 ways (paraffin and freezing) and stained with 2 techniques (hematoxylin/eosin and oil red). In each lamella 10 fields were observed. RESULTS: Normal mature adipose tissue was observed in the control fragments. In those undergoing US, depending on the frequency and time applied, interstitial edema, disordered architecture, presence of inflammatory infiltrate and lysis of adipocyte membranes were observed, in various percentages that we qualified in degrees. Thus, in the fragments exposed for 5 minutes at medium frequency, mild lysis was observed (10%), In those exposed for 10 minutes at medium frequency, lysis was mild to moderate ( 10-20%), similar to that observed with low frequency for 15 minutes. Applying US for 15 minutes with low frequency, the response was mild to moderate (10-20%) with medium frequency of moderate to severe (20-30%) and with high frequency it was frankly severe (30%). CONCLUSIONS: The application of external US causes lysis of the adipocytes and evident disorders in the adipose tissue architecture. Applying it with lower frequencies requires longer periods to achieve the same effects. With higher frequencies the same changes are achieved in less time. The use of frequencies from 2.4 to 3.9 Hz causes obvious changes, with a wide margin of safety

Restoration of the Age Elongated Auricular Lobe.

BACKGROUND: The ears increase in all dimensions over the years (eg, length, helix diameter, lobe length), but the most obvious change is the elongation or ptosis of the lobe. Its correction should be considered a part of facial rejuvenation. OBJECTIVES: The authors presented the surgical procedure they have been utilizing to correct elongated earlobes. METHODS: The authors described a simple and effective procedure consisting of the curved resection of the excess tissue of the lobe at its lower end and its reconstruction through the utilization of 2 triangular flaps of skin, taken from the lateral surface of the lobe, rotated backwards, and sutured to the medial surface, leaving a zigzag hidden scar. RESULTS: The authors have utilized this surgical procedure over the last 16 years to correct ptosis of the earlobe as well as some of its other alterations due to aging. The results obtained are presented as well as the classification that the authors have utilized to qualify their degree of ptosis. CONCLUSIONS: This procedure has yielded excellent results, with imperceptible scars, and is therefore very pleasing to patients and surgeon alike.

Surgical Planning for Mandibular Distraction Osteogenesis Using Low-Cost Three-Dimensional-Printed Anatomic Models.

Mandibular distraction osteogenesis (MDO) is a fairly common procedure in specialized craniofacial surgery centers. The MDO is a minimally invasive technique that is able to generate new bone in patients with a severe hypoplastic ascending ramus, while also expanding the overlying soft tissues; therefore, it has become the treatment of choice for the surgical correction of mandibular hypoplasias. One of the most common postoperative complications involves misplacement of the distractor and/or corticotomy, which can result in the creation of an erroneous distraction vector. The introduction of 3-dimensional (3D) printing has revolutionized preoperative planning in several surgical fields; however, cost can hinder its application in developing nations, specially in public institutions. The aim of this work is present our experience using low-cost 3D-printed anatomic models for preoperative planning and surgical simulation in patients requiring MDO.

El ejercicio de la Medicina y su entorno legal / No disponible

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Dimensional Error in Rapid Prototyping with Open Source Software and Low-cost 3D-printer.

Rapid prototyping models (RPMs) had been extensively used in craniofacial and maxillofacial surgery, especially in areas such as orthognathic surgery, posttraumatic or oncological reconstructions, and implantology. Economic limitations are higher in developing countries such as Mexico, where resources dedicated to health care are limited, therefore limiting the use of RPM to few selected centers. This article aims to determine the dimensional error of a low-cost fused deposition modeling 3D printer (Tronxy P802MA, Shenzhen, Tronxy Technology Co), with Open source software. An ordinary dry human mandible was scanned with a computed tomography device. The data were processed with open software to build a rapid prototype with a fused deposition machine. Linear measurements were performed to find the mean absolute and relative difference. The mean absolute and relative difference was 0.65 mm and 1.96%, respectively (P = 0.96). Low-cost FDM machines and Open Source Software are excellent options to manufacture RPM, with the benefit of low cost and a similar relative error than other more expensive technologies.

Comentario al artículo 'Anatomía quirúrgica de la platismoplastia medial submentoniana. Variabilidad anatómica en cadáveres' / No disponible

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[Mini-invasive surgical procedure to reverse the aging process]. / Procedimiento quirúrgico miniinvasivo para el rejuvenecimiento de la región frontal.

Reduction of the bony structure of the face is the main reason for flabbiness and drooping of the facial soft tissues. Because we do not currently have recourse to restore the lost bony volume, a good possibility is to reestablish an optimal relationship between the soft tissues and the present bony volume. Based on this principle, we have developed the procedure of mini-invasive subperiosteal facial restoration. In this paper we describe the application of this procedure to restore the frontal region. The maneuvers and instrumentation used to perform this procedure through frontal, palpebral or the combination of both approaches are described. Based on the surgical anatomy, orientation and instructions for obtaining the goals of the procedure and to avoid complications are elucidated. Ancillary procedures that may be associated with this procedure are described, as well as detailed postoperative care. Observed complications are noted and a summary of the obtained results, which have shown a high degree of patient and surgeon satisfaction, are reported. Observations from our experience with this method during a 10-year period and the reasons for this being the procedure of our first choice are revealed.

Procedimiento quirúrgico miniinvasivo para el rejuvenecimiento de la región frontal / Mini-invasive surgical procedure to reverse the aging process

La disminución del volumen de la estructura esquelética de la cara ocasiona flacidez de todos los elementos que se apoyan sobre ella y es una de las causas más importantes de su caída. Dado que no contamos con un recurso efectivo para lograr la recuperación del volumen óseo, lo indicado es restaurar la relación entre las partes blandas y el volumen óseo vigente. Ésta es la meta más importante de la ritidectomía subperióstica. Describimos la aplicación de este procedimiento miniinvasivo para la restauración de la región frontal. Se describen las metas y medios para realizarlo por vía frontal, transpalpebral y combinando ambas vías, así como los procedimientos auxiliares asociados, los detalles del manejo posoperatorio, las complicaciones, las observaciones resultantes de nuestra experiencia con este método a lo largo de 10 años y la razón de que actualmente sea nuestro procedimiento de elección.

Reduction of the bony structure of the face is the main reason for flabbiness and drooping of the facial soft tissues. Because we do not currently have recourse to restore the lost bony volume, a good possibility is to reestablish an optimal relationship between the soft tissues and the present bony volume. Based on this principle, we have developed the procedure of mini-invasive subperiosteal facial restoration. In this paper we describe the application of this procedure to restore the frontal region. The maneuvers and instrumentation used to perform this procedure through frontal, palpebral or the combination of both approaches are described. Based on the surgical anatomy, orientation and instructions for obtaining the goals of the procedure and to avoid complications are elucidated. Ancillary procedures that may be associated with this procedure are described, as well as detailed postoperative care. Observed complications are noted and a summary of the obtained results, which have shown a high degree of patient and surgeon satisfaction, are reported. Observations from our experience with this method during a 10-year period and the reasons for this being the procedure of our first choice are revealed.

Restauración frontal miniinvasiva por abordaje mixto / Restoration minimally invasive front by mixed approach

La disminución del volumen de la estructura esquelética de la cara ocasiona flaccidez de todos los elementos que se apoyan sobre ella y su subsecuente caída. A falta de recurso efectivo para lograr la recuperación del volumen óseo, lo indicado es restaurar la relación entre las partes blandas y el volumen óseo vigente. Basados en este principio, hemos desarrollado el procedimiento de restauración facial subperióstico miniinvasivo. En este trabajo describimos la aplicación de este procedimiento para la restauración de la región frontal... Se describen los medios para realizar este procedimiento por las vías frontal y transpalpebral, y combinando ambas vías. Sobre la base de la anatomía quirúrgica, se da orientación para lograr las metas del procedimiento y evitar complicaciones. Se mencionan los procedimientos que se pueden asociar a este procedimiento y se describen los detalles del manejo posoperatorio.

The reduction of the bony structure of the face is the main reason of the flabbiness and fall of the facial soft tissues. Because we do not have already recourses to restore the lost bony volume, a good possibility is to reestablish a good relationship between the soft tissues and the present bony volume. Based on this principle we have developed the procedure of mini-invasive subperiosteal facial restoration. In this paper we described the application of this procedure to restore the frontal region... The maneuvers and instrumentation used to perform this procedure through frontal, aplpebral or combining both approaches are described. Based on the surgical anatomy, orientation and advices to reach the goals of the procedure and to avoid complications are given. The ancillary procedures, which could be associated to this procedure, are described as well as the details of the post-op care.

[Long-term stability with absorbable plates and internal fixation in orthognatic surgery]. / Estabilidad a largo plazo con placas absorbibles para fijación interna en cirugía ortognática.

The author presents his experience using biodegradable self-reinforced polylactide (SR-PLLA) plates, and screws in orthognathic surgery to fixate horizontal and segmentary osteotomies of maxillae in 142 cases. Experience was confirmed by using the same elements to treat acute fractures, old fractures, and craniodisostosis for a total of 208 cases with maximum follow-up of 8 years. Characteristics of these materials are described, as well as the method used to place them; indications and complications are observed.

[Effects of zygomatic arch resection in rat]. / Efectos de la resección del arco cigomático de la rata.

Eighty-two-day-old male Wistar rats were selected to study the pattern of craniofacial growth following partial or total resection of zygomatic arches. Rats were divided into five groups: Group I or control group; group II, with unilateral partial resection of zygomatic arch; group III, with bilateral partial resection; group IV, with unilateral total resection, and group V, with bilateral total resection of zygomatic arch. Direct dry skull and cephalometric measurements showed increased facial projection and decreased transverse facial width on side of resected arch. Different considered points, measured distances, and average results obtained are presented. Conclusions of this study are discussed emphasizing the function of zygomatic arch as moderator of morphologic development and growth of the face. Practical application of this study if results are extrapolated to growth pattern of patients with malformations of zygomatic arch, such as Treacher Collins syndrome, are discussed also, establishing as priority in their treatment the reconstruction of this structure.