[A comparative study of Taylor spatial frame and unilateral external fixator in treatment of tibiofibular open fractures].

OBJECTIVE: To compare the effectiveness of Taylor spatial frame (TSF) and unilateral external fixator in the treatment of tibiofibular open fractures. METHODS: Between January 2016 and July 2018, 74 patients with tibiofibular open fracture who met the selection criteria were divided into TSF group (43 cases, fixed with TSF) and unilateral group (31 cases, fixed with unilateral external fixator) according to the principle of entering the group every other day. There was no significant difference in gender, age, affected side, cause of injury, type of fracture between the two groups ( P>0.05). The operation time, fracture healing time, removal time of external fixator, and complications were recorded and compared between the two groups. The limb function was evaluated according to Johner-Wruhs criteria for evaluating the final effectiveness of tibial shaft fracture treatment. The recovery of lower limb force line was ecaluated by LUO Congfeng et al. criteria. RESULTS: All patients were followed up 8-22 months, with a median of 12 months. All fractures healed, and no complication such as delayed union, nonunion, or osteomyelitis occurred. The operation time, fracture healing time, and removal time of external fixator in TSF group were significantly shorter than those in unilateral group ( P<0.05). At 3 months after the removal of the external fixator, the limb function was evaluated according to the Johner-Wruhs standard. In TSF group, 41 cases were excellent, 1 case was good, and 1 case was fair, and the excellent and good rate was 97.67%; in unilateral group, 30 cases were excellent and 1 case was fair, and the excellent and good rate was 96.77%; there was no significant difference between the two groups ( P=0.666). At 4 months after operation, the recovery of lower limb force line was ecaluated by LUO Congfeng et al. criterion. In TSF group, 41 cases were excellent, 2 cases were good, and 1 case was fair, and the excellent and good rate was 97.67%; in unilateral group, 29 cases were excellent, 1 case was good, 1 case was fair, and the excellent and good rate was 96.77%; there was no significant difference between the two groups ( P=0.666). CONCLUSION: For tibiofibular open fracture, on the premise of fracture healing, TSF technology is superior to unilateral external fixation in terms of shortening operation time, fracture healing time, and removal time of external fixator.

[Clinical application of Taylor spatial frame in adjustment of lower extremity force line of knee medial compartmental osteoarthritis].

OBJECTIVE: To explore the safety and effectiveness of Taylor spatial frame (TSF) in the treatment of medial compartmental osteoarthritis (MCOA) of the knee and the adjustment of the lower extremity force line at the same time. METHODS: The clinical data of 30 patients with MCOA who underwent high tibial osteotomy (HTO) between October 2016 and April 2017 were retrospectively analyzed. According to the different fixation methods, they were divided into external fixation group (TSF external fixation, 16 cases) and internal fixation group (locking steel plate internal fixation, 14 cases). There was no significant difference between the two groups in gender, age, side, disease duration, mechanical femur tibia angle (MFTA), and other general data ( P>0.05). The operation time and intraoperative blood loss of the two groups were recorded and compared; MFTA was used to evaluate the recovery of the lower extremity force line at last follow-up; Hospital for Special Surgery (HSS) score was used to evaluate the clinical effecacy before operation and at 2 weeks, 1 month, and 3 months after operation. RESULTS: The operation time and intraoperative blood loss of external fixation group were significantly less than those of internal fixation group ( P<0.05). All patients were followed up 9-16 months, with an average of 12 months. There were 2 cases of delayed healing in the internal fixation group and 1 case of delayed healing in the external fixation group, and all healed after symptomatic treatment. All patients in the two groups had no complication such as needle infection, nonunion at osteotomy, osteomyelitis, and so on. At last follow-up, MFTA standard was used to evaluate the recovery of force line. The results of external fixation group were all excellent, while the results of internal fixation group were excellent in 10 cases and good in 4 cases. The difference between the two groups was significant ( Z=-2.258, P=0.024). The HSS scores in the two groups were significantly improved at each time point after operation, and gradually improved with time after operation ( P<0.05). The HSS score of the external fixation group was significantly higher than that of the internal fixation group ( t=2.425, P=0.022) at 3 months after operation; and there was no significant difference between the two groups at other time points ( P>0.05). CONCLUSION: TSF has unique advantages in HTO treatment of MCOA patients and correction of lower extremity force line, such as shorter operation time, less bleeding, firm fixation, and less complications. It can accurately adjust the lower extremity force line after operation and has good effectiveness. It is an effective and safe fixation method.

Temporary and definitive external fixation of war injuries: use of a French dedicated fixator.

PURPOSE: External fixation is the recommended stabilization method for both open and closed fractures of long bones in forward surgical hospitals. Specific combat surgical tactics are best performed using dedicated external fixators. The Percy Fx (Biomet) fixator was developed for this reason by the French Army Medical Service, and has been used in various theatres of operations for more than ten years. METHODS: The tactics of Percy Fx (Biomet) fixator use were analysed in two different situations: for the treatment of French soldiers wounded on several battlefields and then evacuated to France and for the management of local nationals in forward medical treatment facilities in Afghanistan and Chad. RESULTS: Overall 48 externals fixators were implanted on 37 French casualties; 28 frames were temporary and converted to definitive rigid frames or internal fixation after medical evacuation. The 77 Afghan patients totalled 85 external fixators, including 13 temporary frames applied in Forward Surgical Teams (FSTs) prior to their arrival at the Kabul combat support hospital. All of the 47 Chadian patients were treated in a FST with primary definitive frames because of delayed surgical management and absence of higher level of care in Chad. CONCLUSION: Temporary frames were mostly used for French soldiers to facilitate strategic air medical evacuation following trauma damage control orthopaedic principles. Definitive rigid frames permitted achieving treatment of all types of war extremity injuries, even in poor conditions.

[Humeral lengthening with a monolateral external fixator in achondroplasia]. / Wydluzenie kosci ramiennej z zastosowaniem dystraktorów monolateralnych u chorych z achondroplazja.

INTRODUCTION: In achondroplasia patients the shortening of upper limb (mainly the arms) is an important part of pathology in addition to low stature. Not all patients who are treated for increasing their height decided to have humeral lengthening and the indication for treatment is not only for cosmetic, psychological aspects but also limitation of upper limb function like self-services and personal hygiene. MATERIAL AND METHODS: 5 patients were evaluated (4 girls and 1 boy) at age of 14 to 18 years (mean 15.7) in whom 10 humeral lengthening were do-ne using monolateral external fixator "Pumed". All patients have lower limb lengthening with the Ilizarov method 4-5 years before humeral lengthening. Observation time was 6 to 34 months (mean 20). In all cases the Pumed external fixator was fixed to humerus by 4 Schanz screws, open humeral distraction osteotomy was done below the insertion of deltoid muscle. In one case 15 degrees anteflexion correction was done intraoperatively. Distraction began at 5-6th day postoperatively with rate of 1 mm/day. Because of hypertrophic bone regenerate the distraction rate was often increased up to 1.5 mm/day. RESULTS: 8 to 9 cm lengthening was achieved (mean 8.5) which represents more than 50% of the primary segmental length. The average time of fixator application was 7 months and the lengthening index ranged from 0.8 to 1.1 months/cm (average 0.85). No shoulder and elbow joint range of motion deterioration was observed. At the follow-up transient radial nerve palsy was observed in one case after acute limb axis correction. CONCLUSIONS: Humerus lengthening, in achondroplasia patients with the use of monolateral external fixator is an effective and reliable method of treatment, with relatively low lengthening index. Monolateral External Fixator are well tolerated by patients.

A functional classification of spinal instrumentation.

BACKGROUND CONTEXT: Spinal instrumentation systems have evolved far beyond the original Harrington design, with increasing complexity and capabilities. This review attempts to de-emphasize the "product names," as systems are often generically and inappropriately referred to as "Harrington rods," by introducing a functional classification for current systems. PURPOSE: The aim of this paper is to review the intended design purpose of current spinal instrumentation systems for more accurate interpretations of radiographs and complications. STUDY DESIGN: The principles involved in each type of instrumentation system are described, followed by the characteristic components and the normal appearance radiographically, with examples of complications, which should be recognized. METHODS: The historical contribution of specific systems in the developing art of internal fixation of the spine is provided as a background to understand the biomechanical forces imparted by spinal hardware. Recognizing the functional intent of spinal constructs will enhance descriptions of those images. RESULTS: Spinal instrumentation has been categorized into five functional types: Distraction and compression, segmental stabilization, coupled or derotation systems, translational or pedicle screw systems, and anterior instrumentation. CONCLUSIONS: Analysis of radiographs from a functional viewpoint can enhance the descriptive interpretation and specifically allow assessment of the success or of the presence of complications, which are crucial to the analysis of instrumentation effectiveness.

Stiffness characteristics and inter-fragmentary displacements with different hybrid external fixators.

OBJECTIVES: To determine how the different approaches of constructing a hybrid external skeletal fixator affect the mechanical environment at the fracture site. DESIGN: A comparative biomechanical analysis of external fixators that represent a spectrum of designs from unilateral to circular fixators. BACKGROUND: The most pertinent parameter that affects fracture healing is the inter-fragmentary displacement. Most studies on the mechanical performance of external fixators have concentrated on the overall stiffness of the fixators. METHODS: Mechanical testing was performed on four types of hybrid fixators in which the overall stiffness of the fixator as well as the axial, transverse shear and angular displacements at the fracture site were measured. RESULTS: The Ilizarov hybrid fixator with one wire and one screw on each ring behaved more like a unilateral fixator than a circular fixator. The bar-ring hybrid fixator that simply connected a unilateral fixator body to a wire/ring assembly was too flexible. Reinforcing the bar-ring hybrid system with diagonally placed struts eliminated the deformation associated with the unilateral body and the resulting construct performed considerably better. The two-ring hybrid fixator most closely resembled the Ilizarov fixator. CONCLUSIONS: Depending on the construction characteristics hybrid fixators possess a spectrum of mechanical characteristics of both unilateral and circular fixators. The constructions using two rings in which at least one bone segment is supported entirely by wires appears to have the best mechanical characteristics. RELEVANCE: Understanding how the different approaches of constructing a hybrid fixator affect the mechanical environment at the fracture site will enable surgeons to chose or build the most appropriate fixator for each clinical situation.

Effect of a supplemental plate on the stiffness of a type I external fixator.

OBJECTIVE: To assess the effect of a supplemental plate on the stiffness of a six-pin unilateral external skeletal fixator. STUDY DESIGN: Mechanical testing performed on models. METHODS: Wooden (birch) dowels were used to create five models of a fracture. A commercially available external fixation system was applied to the model with a uniform unilateral six-pin fixator design. The models were mechanically tested with and without a supplemental plate attached to the 2 clamps adjacent to the fracture gap. Testing was conducted in axial loading, medial to lateral bending, and cranial to caudal bending. RESULTS: Results showed a 4.42-fold increase in stiffness in axial load, a 4.23-fold increase in stiffness in medial to lateral bending, and a 1.94-fold increase in stiffness in cranial to caudal bending with the addition of the plate. CONCLUSIONS: The addition of a supplemental plate increases the mechanical stiffness of unilateral fixators. This was especially true in axial load and medial to lateral bending. CLINICAL RELEVANCE: A supplemental plate can be used with unilateral fixators to increase stiffness of the fixator. Conversely, the plate can be removed to decrease stiffness without the removal of fixation pins.

Structural stiffness and reducibility of external fixators placed in malalignment and malrotation.

OBJECTIVE: To determine the structural stiffness and reducibility of various external fixators placed in malalignment and malrotation. DESIGN: Uniform testing of all external fixator configurations. SETTING: Orthopaedic biomechanical laboratory. METHODS: Thirteen external fixators from different manufacturers, in a total of fifteen configurations, were studied. All external fixators were applied to a malreduction jig initially, and a subsequent anatomic reduction was then attempted. If an anatomic reduction was possible, the structural stiffness of those fixators was determined. If anatomic reduction was not possible, the external fixator was removed and reapplied to an anatomically reduced model, and then structural stiffness was determined. RESULTS: Six of the thirteen external fixator configurations allowed an anatomic reduction after placement on a malreduction model. The other nine external fixator configurations would not allow for an anatomic reduction. All the external fixator configurations were biomechanically tested in anteroposterior bending, lateral bending, axial load, and torsion. Each fixator had its own structural stiffness and is reported. CONCLUSIONS: Some external fixators will not allow for an anatomic reduction once placed in malalignment and malrotation without repositioning of the fixator pins. External fixator configurations (i.e., single-pin, dual-pin, and multipin barclamps) affect structural stiffness. Structural stiffness widely varied among the external fixators. Proper external fixator selection will enable early fracture immobilization in malalignment and malrotation in suboptimal conditions (e.g., wartime conditions or a civilian disaster), with subsequent external fixator adjustment for an anatomic reduction.

Fijación intramedular en las fracturas diafisarias de tibia Hospital Escuela Antonio Lenin Fonseca, enero 1998, enero 2001 / Intramedullary fixation in tibia diaphyseal fractures Hospital Antonio Lenin Fonseca (HALF), january 1998, january 2001

Se realizo un estudio para evaluar el manejo de pacientes con fijación IM (intramedular), según características de las fracturas de tibia e implante utilizado. Los implantes utilizados fueron clavos IM bloqueados tipo Gross Kempfe, clavo IM no bloqueado tipo Kuntscher Clásico y clavo IM de Lottes. Es importante hacer notar que el HEALF ha sido pionero como centro hospitalario público en la utilización de Técnicas de Fijación IM bloqueadas. Este materialha sido donado al Servicio de Ortopedia gracias a la gestión del Dr. Warren Pagel. Se evaluaron las características biológicas y sociales de los pacientes con fijación intramedular de tibia, así como la técnica e implante utilizado según eltipo de fractura. Para la evaluación de los resultados nos basamos en los criterios de Jhoners-Wursh. El estudio refleja que las características biológicas y sociales de nuestros pacientes son similares a la de estudios previos y que el resultado en el manejo de las fracturas de tibia con fijación intramedular es excelente en un 72.72 porciento de los casos lo cual es muy satisfactorio, pero se puede mejorar teniendo acceso a mayor variedad y set completos de implantes para cada patrón de fractura

External ring fixators: an overview.

External fixation is widely used in the fixation of fractures and limb deformities. The mechanical characteristics of a specific external fixator are major factors in determining the biomechanical environment at a fracture/osteotomy site and, hence, affect the healing process. Although the optimal biomechanical environment for healing of a fracture or an osteotomy is unknown, a specific range of interfragmentary motion exists which promotes healing. It is therefore desirable that the mechanics of an external fixator can be manipulated to enable the surgeon to control the range of interfragmentary motion. The characteristics of an external fixator are defined by a large number of variables. Therefore, to gain control over the degree of interfragmentary motion, an understanding of the effect of each variable and how it interacts with the others to determine the overall characteristics of the device is required. For the past two decades, individual components and whole-frame configurations have been studied in depth. This article provides a summary of previous work concerning the mechanics of external ring fixators and how they affect the biomechanical environment at the fracture/osteotomy site.

El fijador externo en la extremidad superior catastrófica / The external fixator in the mangled upper extremity

Presentamos la experiencia del uso de la fijación externa en lesiones complejas de la extremidad superior, en un reimplante y cuatro revascularizaciones. Hemos realizado procedimientos de cirugía conservadora primaria y diferida, y en todos ellos el fijador externo ha sido el dispositivo de osteosíntesis utilizado. Pensamos que el fijador externo es capaz de estabilizar la fractura y de facilitar la compleja cirugía del reimplante o de revascularización. Asimismos,es a la vez capaz de asegurar la estabilidad y facilitar los procesos reconstructivos en la cirugía secundaria. Concluimos que la fijación externa puede ser útil en casos seleccionados de cirugía de la extremidad catastrófica. (AU)

Transporte óseo de la tibia con método de Ilizarov en los casos de pseudoartrosis con falla ósea / Bone transportation of the tibia by the Ilizarov technique in cases of non-union with bone loss

Se trataron 21 pacientes portadores de pseudoartrosis tibial con falla ósea, con el método de Ilizarov, 17 del sexo masculino y 4 del femenino, con promedio de 25.4 años de edad (4 a 47 años). El momento de evaluación después del retiro del fijador fue de 38.5 meses (3 a 78 meses). El tratamiento se basó en la técnica de transporte óseo de tibia para la recuperación de la pérdida ósea, siendo bifocal en 20 pacientes y trifocal en un paciente. Fue necesaria la revisión quirúrgica en el sitio de la pseudoartrosis en 7 pacientes, para el retiro del tejido interpuesto y reavivar los extremos óseos de los fragmentos. El tratamiento inicial consistió en la resección amplia del tejido necrótico óseo, en el sitio de la pseudoartrosis, y después de resuelto el proceso infeccioso se hizo corticotomía metafisaria subperióstatica para el transporte óseo. El promedio obtenido de transporte óseo era de 6.93 cm (2.0 a 18.0 cm). El tiempo promedio de transporte óseo era de 11.0 semanas (2 a 30 semanas). Se observaron complicaciones en 2 casos de refractura después del retiro del fijador externo circular, un caso de osteomielitis crónica en el trayecto de un clavo de Schanz que necesitó abordaje quirúrgico; limitación de la movilidad del tobillo en 2 casos y de la rodilla en 2 casos. Dos casos necesitaron artrodesis del tobillo, porque la falla ósea comprometió la articulación. El promedio de acortamiento residual fue de 1.85 cm (0.0 a 12.0 cm), siendo 15 pacientes con menos de 2.0 cm. Sólo en un paciente se colocó yeso ambulatorio durante 3 meses después del retiro del fijador. Se observó desviación del eje en tres pacientes, sin daño funcional, uno con valgo menor de 10 grados y antecurvatum menor de 5 grados y otro con antecurvatum de 15 grados. Veinte pacientes retornaron a sus actividades anteriores, excepto un paciente alconhólico. Los reusltados clínico-funcionales fueron excelentes en 10, buenos en 9 y malos en 2. Radiológicamente los resultados fueron 11 excelentes, 8 buenos y 2 malos. Podríamos considerar resultados excelentes y buenos en 90.47 por ciento de los casos

Fracturas diafisarias del húmero su tratamiento con fijador externo uniplanar roscado con una compresión gradual / Humeral diaphyseal fractures. Their treatment by uniplanar external fixator with threaded screw with a gradual compression

Se presenta una serie de 16 casos con fractura diafisaria del húmero siendo el tipo de lesión de acuerdo con la clasificación de la AO: A: 37.50 por ciento, B: 31.25 por ciento y C: 31.25 por ciento. Los pacientes, 12 hombres y 4 mujeres fueron tratados con fijador externo roscado y con compresión gradual 1 mm por día por espacio de 10 días. Los resultados fueron excenlentes dado el tiempo de consolidación de 10.1 semanas. Se presentaron mínimas complicaciones, movilidad temprana, tiempo quirúrgico menor, facilidad de colocación, escaso material y facilitación de la consolidación por la compresión gradual que estimula la formación trabecular

Tratamiento de las fracturas de Colles mediante ligamentotaxis con fijador externo uniplantar de Bahumer / Treatment for Colles's fractures by ligementotaxis with the monoplanar external fixator of Bahumer

De agosto de 1991 a noviembre de 1996 se trataron 100 pacientes de 40 a 82 años (promedio 61) con fractura de Colles conminuta, desplazada, impactada, con acortamiento radial e intra-articular, mediante ligamentotaxis sostenida con fijador externo uniplanar y además en las que tuvieran incongruencia articular mayor de 2 mm, con fijación adicional mediante alambres de kirschner e injerto en aquellas que hubieran tenido pérdida de substancia por colapso. La mayoría fueron tipos VII y VIII de Frykman. El 62 por ciento tuvo reducción completa de la superficie articular; el 65 por ciento no tuvo dolor; el 60 por ciento retornaron a su trbajo en 13 semanas en promedio. El 46 por ciento requirió aplicación de injerto óseo complementario. Como complicaciones se tuvo infección superficial en el sitio de los clavos en el 13 por ciento, distrofia simpática refleja en 2 por ciento y severa disminución de la fuerza muscular en un caso (1 por ciento)

Minifijadores externos AO/ASIF en el tratamiento de las fracturas distales del radio / AO/ASIF external mini fixators for treatment of distal fractures of the radius

Se presenta un estudio comparativo entre 2 series de pacientes con fractura distal del radio. El primero se integró con 37 casos de ambos sexos, con edades de 17 a 84 años, con fracturas tipo V, VI, VII y VIII de Frykman, que se trataron con minifijador externo AO/ASIF. El segundo se formó con 12 pacientes con edades de 21 a 78 años, con fracturas tipos VI, VII y VIII de la misma clasificación, que se trataron mediante manipulación cerrada y yeso. El tiempo de consolidación fue similar en ambos grupos, sin embargo el primer grupo tuvo menor atrofia muscular, mejor movilidad y reincorporación al trabajo en mejores condiciones funcionales

Uso de minifijadores externos en el tratamiento de la corrección quirúrgica del pie equino varo aducto congénito / The use of external minifixators for treatment of surgical correction of clubfoot

El pie equinovaro aducto congénito es una deformidad conocida desde la antiguedad y su tratamiento es variado, sin embargo no se ha logrado su completa corrección. Este estudio pretende mantener la corrección completa mediante el uso minifijadores externos colocados a partir de cualquier técnica quirúrgica, obténiendose el control completo de la herida, y del estado neurocirculatorio al visualizar completamente el pie, a fin de detectar oportunamente cualquier complicación. También se observó una reducción de la tensión en la piel y tejidos blandos y por último se puede iniciar en forma temprana la movilización del pie. Se estudian un total de 12 pacientes con 13 pies tratados, entre los 11 meses y los 3 años; en 8 casos los resultados fueron excelentes, en 3 muy buenos, 1 bueno y 0 malos, Los fijadores se mantuvieron 10 semanas aproximadamente y la resolución fue en general íntegra y satisfactoria

Alargamiento óseo con el fijador del Dr. Espinosa. Experiencia de 5 años en el Instituto Nacional de Pediatría / Bone lenghtening by Espinosa external fixator. Experience of 5 years of National Institute of Pediatrics

Objetivo: Determinar el porcentaje del alargamiento óseo en pacientes con discrepancia de miembros pélvicos, con respecto al miembro contralateral, al terminar el tratamiento con el fijador del Dr. Espinosa. Estudio retrospectivo, descriptivo, longitudinal y observacional. Departamento de Ortopedia Pediátrica del Instituto Nacional de pediatría, del primero de julio de 1995 al 24 de febrero de 1996. Se seleccionaron los expedientes clínicos y radiológicos de los pacientes elongados por discrepancia de miembros inferiores con el fijadro de Epinosa, en el lapso citado, que fueron intervenidos quirúrgicamente en el Instituto. En dichos pacientes se investigó: edad, discrepancia con respecto al miembro contralateral, lapso transcurrido, consolidación obtenida y complicaciones. Doce pacientes cumplieron con los criterios de selección del estudio. Su edad promedio fue de once años y medio, con una desviación estándar (ñ DE) de dos años 7 meses, La discrepancia observada fue de 7.07 (ñ 2.33) cm. Los pacientes estuvieron 9 meses y medio (ñ 2 meses) en tratamiento y se obtuvo el 96.4 por ciento (ñ 4.6) del alargamiento deseado. En 7 casos no hubo complicaciones. Se presentó pie equino en 3 pacientes; en otro caso pseudoartrosis y mala alineación en otro. Los pacientes en los que permaneció más tiempo el fijador, estaban en una percentila menor de talla. Sin embargo, en todos los pacientes se logró una adecuada consolidación

Fijación externa realizada en el hospital III José Cayetano Heredia de Piura, años 92-94 / External-fixation carried out in the Hospital III Cayetano Heredia of Piura (1992-1994)

Se presentan 35 casos de pacientes con fracturas expuestas mayormente de tibia, peroné y fémur tratados con el método de fijación externa en el Hospital III Cayetano Heredia del IPSS- Piura a partir del mes de octubre del 92 al mes de agosto del 94 como estudio preliminar. En razón del elevado número de pacientes accidentados se dan a conocer los resultados y las ventajas que ofrece esta técnica en nuestra especialidad demostrando su eficacia. La mayoría de los pacientes fueron no asegurados del sexo masculino, con un promedio de 37.7 años y las fracturas más frecuentes se presentaron entre 20 a 39 años. La mayor causa de fracturas expuestas fueron por accidentes de tránsito en el lado derecho de la extremidad inferior y el aparato de fijación externa fue colocado en promedio en 4.5 meses preferentemente de tipo bilateral. Se colocó injerto de piel, injerto de esponjosa y se realizaron injertos músculo tendinosos en los pacientes de mayor gravedad. La pseudoartrosis e infecciones y acortamientos son las aplicaciones más frecuentes, el gérmen que más se aisló ha sido Citrobacter y E. Coli. Se ha usado mayormente Cefalosporina y Aminoglúcidos. La estancia promedio fue de 31.6 días y la evolución ha sido favorable en un 77.14 por ciento. El costo total promedio asciende a 2,500 dólares aproximadamente.