Enclavado endomedular tibial: ¿Logra la vía de abordaje suprapatelar la misma reducción radiológica?

El tractament definitiu de les fractures tibials motiva diversos punts de controvèrsia. La via d'abordatge suprapatelar en posició de semiextensió, per al enclavat endomedul.lar tibial anterógrad, es va dissenyar amb l'objectiu principal d'evitar complicacions de l'abordatge tradicional trans o paratendó rotulià, com són la reducció de les fractures diafisàries proximals tibials i reduir el dolor anterior de genoll. Aquest nou abordatge quirúrgic, descrit al 2009, a més ha d'oferir uns resultats postoperatoris radiològics iguals o millors a la via d'abordatge tradicional. En aquest treball, s'ha descrit l'alineació radiològica postoperatòria, d'una sèrie de pacients afectes de fractura diafisaria tibial, tractats mitjançant abordatge suprapatelar i enclavat endomedul.lar a l'Hospital Vall d'Hebron.

Estudio de la alineación rotacional en la artroplastia total de rodilla mediante tomografía computarizada

L'alineació rotacional a l'astroplàstia total de genoll es refereix a la posició dels implants en el pla axial. Un mínim desplaçament afectarà la distribució de la càrrega y variarà l'estabilitat, l'alineació i la cinemàtica de l'articulació. Tot i que hi ha un consens pel que fa als efectes adversos d'una alineació rotacional incorrecta, encara no està clar quines són les referències anatòmiques que cal utilitzar. Les mesures de l'alineació rotacional requereixen un estudi d'alta qualitat. La TC és la modalitat d'imatge d'elecció per a l'estudi postoperatori de l'artroplàstia total de genoll. L'objectiu d'aquest treball es avaluar la capacitat diagnòstica de la TC per a l'estudi de l'alineació rotacional postoperatòria en l'artroplàstia total de genoll i presentar les variacions en el protocol de TC que minimitzen l'artefacte metàl•lic. Aquest estudi avalua la reproductibilitat de l'angle condili posterior, format per l'eix epicondili quirúrgic i la línia bicondilia posterior, mesurant la correlació entre dos observadors. El coeficient de correlació de Pearson mostra una forta correlació positiva (R=0.84) entre els dos observadors. La mitja d'error de les mesures adquirides és de -0.14º amb una desviació estàndar de 2.06º (-0.14 ± 2.06), per la qual cosa la modificació dels paràmetres tècnics de la TC per a la minimització dels artefactes metàl•lics és eficaç per l'avaluació rotacional. No obstant, l'alta magnitud de l'error indica que el radiòleg ha de ser prudent en el diagnòstic de mínimes variacions angulars que impliquin canvis en l'actitud mèdica i terapèutica.

El escafoides accesorio y su relación con el pie valgo-plano

Se estudia la patología dolorosa, que en ocasiones, puede producir la existencia de un escafoides accesorio del tarso. Este hueso accesorio generalmente se une al escafoides con la maduración ósea, hacia la adolescencia, mediante un centro secundario de osificación, En ocasiones se vuelve doloroso cuando, en esta edad, existe un exceso de tracción del tendón del tibial posterior, el cual se inserta en este centro secundario de sificación; esto puede ser producido por la presencia de un pie valgo-plano o por la realización de una fuerte actividad física. También, aquellos accesorios que son muy prominentes, pueden volverse sintomáticos con el roce con el calzado. Inicialmente el tratamiento será conservador, evitando el exceso de tracción del tendón del tibial posterior mediante reposo, y con la utilización de un soporte plantar que disminuya la pronación del pie. Esperando la osificación de ambos huesos, en la gran mayoría de las veces desaparecen los síntomas. Solamente en algunos casos es necesaria la intervención quirúrgica, la cual consiste en la simple exéresis del accesorio. En éste artículo se desmiente, de forma argumentada, la hipótesis de que el escafoides accesorio produce un pie valgo-plano. No obstante, si se constata la importante asociación que hay entre su existencia cuando es sintomático y el aplanamiento del pie; la explicación que se da a esto es que, cuando hay un pie plano, el exceso de pronación que este ocasiona provocará un exceso de tracción del tendón del tibial posterior sobre el accesorio,convirtiéndolo en doloroso; éstos son los pies que vienen a la consulta, y no los asintomáticos, dando la falsa impresión de que el escafoides accesorio provoca un pie valgo-plano.

Contribution of femoral and proximal sciatic nerve branches to the sensory innervation of hindlimb digits in the rat

The present study was performed to investigate the possibility of 'aberrant' innervation of the tips of the hindlimb digits in the rat, i.e., from other sources than the femoral and the main sciatic branches (tibial, peroneal, sural). Cutaneous injections of fluorescent tracers in the digits were combined with either selective nerve transections to restrict afferent routes followed by detection of labeled neurons in dorsal root ganglia (DRGs), or by a delayed application of a second tracer to afferent nerves under study to detect double labeled neurons in DRGs. The results show that the tips of the digits were represented in DRGs L3-6. The femoral nerve afferents from digits 1 and 2 projected primarily to DRG L3 and to a smaller extent to DRG L4. A small number of neurons from primarily medial digits 1 and 2, but also from lateral digits 3-5, were found to project to DRGs L4 and L5 via a proximal branch that leaves the sciatic nerve near the sciatic notch and runs distally in the posterior part of the thigh, here called the musculocutaneous nerve of the hindlimb. We also have some evidence indicating innervation of the tips of the digits from the posterior cutaneous nerve of the thigh. Aberrant innervation such as that described here might contribute to remaining and perhaps abnormal sensibility after nerve injury and is of interest for the interpretation of results in experimental studies of collateral and regenerative sprouting after such injury

Postnatal ontogenesis of the tibia. Implications for age and sex estimation

The growth of five variables of the tibia (diaphyseal length, diaphyseal length plus distal epiphysis, condylo-malleolar length, sagittal diameter of the proximal epiphysis, maximum breadth of the distal epiphysis) were analysed using polynomial regression in order to evaluate their significance and capacity for age and sex determination during and after growth. Data were collected from 181 (90♂ and 91♀) individuals ranging from birth to 25 years of age and belonging to three documented collections from Western Europe. Results indicate that all five variables exhibit linear behaviour during growth, which can be expressed by a first-degree polynomial function. Sexual significant differences were observed from age 15 onward in the two epiphysis measurements and condylo-malleolar length, suggesting that these three variables could be useful for sex determination in individuals older than 15 years. Strong correlation coefficients were identified between the five tibial variables and age. These results indicate that any of the studied tibial measurements is likely to serve as a useful source for estimating sub-adult age in both archaeological and forensic samples.

BS-SEM evaluation of the tisular interactions between cortical bone and calcium-phosphate covered titanium implants

The improvement of the reliability of the contact between the osseous tissues and the implant materials has been tested by recovering the metallic implants with ceramic materials, usually calcium phosphates. In our study, the calcium phosphate recovering layers were deposited by means of a pulsed-laser deposition technique. Our aim was to to evaluate the tissue interactions established between cortical bone and titanium implants covered by five different layers, ranging from amorphous calcium phosphate to crystalline hydroxyapatite, obtained by altering the parameters of the laser ablation process. The surgical protocol of the study consisted in the simultaneous implantation of the five types of implants in both the tibial dyaphisis of three Beagle dogs, sacrificed respectively one, two and three months after the last surgical procedures. After the sacrifice, the samples were submitted to a scheduled procedure of embedding in plastic polymers without prior decalcification, in order to perform the ultrastructural studies: scanning microscopy with secondary and backscattered electrons (BS-SEM). Our observations show that both in terms of the calcified tissues appearing as a response to the presence of the different coatings and of time of recovering, the implants coated with crystalline calcium phosphate layers by laser ablation present a better result than the amorphous-calcium-phosphate-coated implants. Moreover, the constant presence of chondroid tissue, related with the mechanical induction by forces applied on the recovering area, strongly suggests that the mechanisms implied in osteointegration are related to endomembranous, rather than endochondral ossification processes

BS-SEM evaluation of the tisular interactions between cortical bone and calcium-phosphate covered titanium implants

The improvement of the reliability of the contact between the osseous tissues and the implant materials has been tested by recovering the metallic implants with ceramic materials, usually calcium phosphates. In our study, the calcium phosphate recovering layers were deposited by means of a pulsed-laser deposition technique. Our aim was to to evaluate the tissue interactions established between cortical bone and titanium implants covered by five different layers, ranging from amorphous calcium phosphate to crystalline hydroxyapatite, obtained by altering the parameters of the laser ablation process. The surgical protocol of the study consisted in the simultaneous implantation of the five types of implants in both the tibial dyaphisis of three Beagle dogs, sacrificed respectively one, two and three months after the last surgical procedures. After the sacrifice, the samples were submitted to a scheduled procedure of embedding in plastic polymers without prior decalcification, in order to perform the ultrastructural studies: scanning microscopy with secondary and backscattered electrons (BS-SEM). Our observations show that both in terms of the calcified tissues appearing as a response to the presence of the different coatings and of time of recovering, the implants coated with crystalline calcium phosphate layers by laser ablation present a better result than the amorphous-calcium-phosphate-coated implants. Moreover, the constant presence of chondroid tissue, related with the mechanical induction by forces applied on the recovering area, strongly suggests that the mechanisms implied in osteointegration are related to endomembranous, rather than endochondral ossification processes

BS-SEM evaluation of the tisular interactions between cortical bone and calcium-phosphate covered titanium implants

The improvement of the reliability of the contact between the osseous tissues and the implant materials has been tested by recovering the metallic implants with ceramic materials, usually calcium phosphates. In our study, the calcium phosphate recovering layers were deposited by means of a pulsed-laser deposition technique. Our aim was to to evaluate the tissue interactions established between cortical bone and titanium implants covered by five different layers, ranging from amorphous calcium phosphate to crystalline hydroxyapatite, obtained by altering the parameters of the laser ablation process. The surgical protocol of the study consisted in the simultaneous implantation of the five types of implants in both the tibial dyaphisis of three Beagle dogs, sacrificed respectively one, two and three months after the last surgical procedures. After the sacrifice, the samples were submitted to a scheduled procedure of embedding in plastic polymers without prior decalcification, in order to perform the ultrastructural studies: scanning microscopy with secondary and backscattered electrons (BS-SEM). Our observations show that both in terms of the calcified tissues appearing as a response to the presence of the different coatings and of time of recovering, the implants coated with crystalline calcium phosphate layers by laser ablation present a better result than the amorphous-calcium-phosphate-coated implants. Moreover, the constant presence of chondroid tissue, related with the mechanical induction by forces applied on the recovering area, strongly suggests that the mechanisms implied in osteointegration are related to endomembranous, rather than endochondral ossification processes

Persistence of tracer in the application site -a potential confounding factor in nerve regeneration studies

Selective reinnervation of peripheral targets after nerve injury might be assessed by injecting a first tracer in a target before nerve injury to label the original neuronal population, and applying a second tracer after the regeneration period to label the regenerated population. However, altered uptake of tracer, fading, and cell death may interfere with the results. Furthermore, if the first tracer injected remains in the target tissue, available for 're-uptake' by misdirected regenerating axons, which originally innervated another region, then the identification of the original population would be confused. With the aim of studying this problem, the sciatic nerve of adult rats was sectioned and sutured. After 3 days, to allow the distal axon to degenerate avoiding immediate retrograde transport, one of the dyes: Fast Blue (FB), Fluoro-Gold (FG) or Diamidino Yellow (DY), was injected into the tibial branch of the sciatic nerve, or in the skin of one of the denervated digits. Rats survived 2-3 months. The results showed labelled dorsal root ganglion (DRG) cells and motoneurones, indicating that late re-uptake of a first tracer occurs. This phenomenon must be considered when the model of sequential labelling is used for studying the accuracy of peripheral reinnervation.

Estimations of topographically correct regeneration to nerve branches and skin after peripheral nerve injury and repair.

Peripheral nerve injury is typically associated with long-term disturbances in sensory localization, despite nerve repair and regeneration. Here, we investigate the extent of correct reinnervation by back-labeling neuronal soma with fluorescent tracers applied in the target area before and after sciatic nerve injury and repair in the rat. The subpopulations of sensory or motor neurons that had regenerated their axons to either the tibial branch or the skin of the third hindlimb digit were calculated from the number of cell bodies labeled by the first and/or second tracer. Compared to the normal control side, 81% of the sensory and 66% of the motor tibial nerve cells regenerated their axons back to this nerve, while 22% of the afferent cells from the third digit reinnervated this digit. Corresponding percentages based on quantification of the surviving population on the experimental side showed 91%, 87%, and 56%, respectively. The results show that nerve injury followed by nerve repair by epineurial suture results in a high but variable amount of topographically correct regeneration, and that proportionally more neurons regenerate into the correct proximal nerve branch than into the correct innervation territory in the skin

Tromboflebitis profundas en la edad infantil

Se recogen cinco casos de variada etiolog{a (osteomielitis del ilíaco, coma diabético hiperosmolar, sepsis meningocócica con shock y C.I.D., traumatismo de cadera y cateterización de vena femoral) que cursaron con tromboflebitis profunda de vasos importantes (venas iliofemoral, femoral y tibial posterior). Se analiza la etiopatogenia de la trombogénesis y los tres principales grupos de afecciones que van a originar enfermedad tromboembólica, aquellas que producen estado de hipercoagulabilidad, las que producen alteración hemodinámica con estasis, y las causantes de lesión tisular. Finalmente se recuerda la clínica, metodos diagnósticos y tratamiento actual de esta entidad poco frecuente en la edad pediátrica