<?xml version="1.0" encoding="ISO-8859-1"?><article xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<front>
<journal-meta>
<journal-id>2306-4102</journal-id>
<journal-title><![CDATA[Acta ortopédica mexicana]]></journal-title>
<abbrev-journal-title><![CDATA[Acta ortop. mex]]></abbrev-journal-title>
<issn>2306-4102</issn>
<publisher>
<publisher-name><![CDATA[Colegio Mexicano de Ortopedia y Traumatología A.C.]]></publisher-name>
</publisher>
</journal-meta>
<article-meta>
<article-id>S2306-41022019000500308</article-id>
<title-group>
<article-title xml:lang="en"><![CDATA[Ligamentum flavum in lumbar spinal stenosis, disc herniation and degenerative spondylolisthesis. An histopathological description]]></article-title>
<article-title xml:lang="es"><![CDATA[Ligamento amarillo en estenosis lumbar espinal, hernia de disco y espondilolistesis degenerativa. Una descripción histopatológica]]></article-title>
</title-group>
<contrib-group>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Reyes-Sánchez]]></surname>
<given-names><![CDATA[A]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[García-Ramos]]></surname>
<given-names><![CDATA[CL]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Deras-Barrientos]]></surname>
<given-names><![CDATA[CM]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Alpizar-Aguirre]]></surname>
<given-names><![CDATA[A]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Rosales-Olivarez]]></surname>
<given-names><![CDATA[LM]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Pichardo-Bahena]]></surname>
<given-names><![CDATA[R]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
</contrib-group>
<aff id="Af1">
<institution><![CDATA[,National Institute of Rehabilitation Division of Spine Surgery ]]></institution>
<addr-line><![CDATA[ ]]></addr-line>
<country>Mexico</country>
</aff>
<aff id="Af2">
<institution><![CDATA[,National Institute of Rehabilitation «Luis Guillermo Ibarra Ibarra»  ]]></institution>
<addr-line><![CDATA[ ]]></addr-line>
<country>Mexico</country>
</aff>
<aff id="Af3">
<institution><![CDATA[,National Hospital  ]]></institution>
<addr-line><![CDATA[San Miguel ]]></addr-line>
<country>El Salvador</country>
</aff>
<aff id="Af4">
<institution><![CDATA[,National Institute of Rehabilitation «Luis Guillermo Ibarra Ibarra»  ]]></institution>
<addr-line><![CDATA[ ]]></addr-line>
<country>Mexico</country>
</aff>
<aff id="Af5">
<institution><![CDATA[,National Institute of Rehabilitation «Luis Guillermo Ibarra Ibarra»  ]]></institution>
<addr-line><![CDATA[ ]]></addr-line>
<country>Mexico</country>
</aff>
<aff id="Af6">
<institution><![CDATA[,National Institute of Rehabilitation «Luis Guillermo Ibarra Ibarra»  ]]></institution>
<addr-line><![CDATA[ ]]></addr-line>
<country>Mexico</country>
</aff>
<pub-date pub-type="pub">
<day>00</day>
<month>10</month>
<year>2019</year>
</pub-date>
<pub-date pub-type="epub">
<day>00</day>
<month>10</month>
<year>2019</year>
</pub-date>
<volume>33</volume>
<numero>5</numero>
<fpage>308</fpage>
<lpage>313</lpage>
<copyright-statement/>
<copyright-year/>
<self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_arttext&amp;pid=S2306-41022019000500308&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_abstract&amp;pid=S2306-41022019000500308&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_pdf&amp;pid=S2306-41022019000500308&amp;lng=en&amp;nrm=iso"></self-uri><abstract abstract-type="short" xml:lang="en"><p><![CDATA[Abstract:  Introduction:  Changes in ligamentum flavum (LF) related to degeneration are secondary to either the aging process or mechanical instability. Previous studies have indicated that LF with aging shows elastic fiber loss and increased collagen content, loss of elasticity may cause LF to fold into the spinal canal, which may further narrow of the canal.  Material and methods:  A total of 67 patients operated with the surgical indications of lumbar spinal stenosis (LSS), lumbar disc herniation (LDH) and lumbar degenerative spondylolisthesis (LDS) were included. LF samples were obtained from patients who had LSS (39), LDH (22) and LDS (6). Specimens were examined with regard to chondroid metaplasia, calcification, fragmentation of collagen fibers, cystic degeneration, fibrillar appearence, and hypercellularity.  Results:  The most frequent histopathological changes were hyalinization and fragmentation of collagen fibers occur in 34%, neovascularization in 40.3% and irregular arrangement of elastic fibers is the most prevalent change with 56.7% of the total samples. There is a difference in the presence of certain changes in the LF according to the diagnosis, being statistically significant for fragmentation of collagen fibers (p = 0.045), cystic degeneration (p = 0.001), fibrillar appearance (p = 0.007) and hypercellularity (p = 0.005) all of these, being more prevalent in LDS group. LHD group presented fragmentation of collagen fibers in 45.5% (p = 0.045) and fibrillar appearance in 4.5% (p = 0.009).  Conclusions:  There is not evidence of cellular hyperthophy in the histhopatological analyses, thickening of the LF can be seen by bulking of LF followed by collapse of motion segment.]]></p></abstract>
<abstract abstract-type="short" xml:lang="es"><p><![CDATA[Resumen:  Introducción:  Los cambios en el ligamento flavum (LF) relacionados con la degeneración son secundarios al proceso de envejecimiento o a la inestabilidad mecánica. Estudios anteriores han indicado que LF con envejecimiento muestra pérdida de fibras elásticas y aumento del contenido de colágeno, la pérdida de elasticidad puede hacer que el LF se pliegue en el canal espinal, disminuyendo su espacio.  Material y métodos:  Se incluyeron 67 pacientes operados de estenosis lumbar espinal (LSS), hernia de disco lumbar (LDH) y espondilolistesis degenerativa (LDS). Se obtuvieron muestras de LF de pacientes que tenían LSS (39), LDH (22) y LDS (6). Se examinaron especímenes con respecto a metaplasia condroide, calcificación, fragmentación de fibras de colágeno, degeneración quística, apariencia fibrilar e hipercelularidad.  Resultados:  Los cambios histopatológicos más frecuentes fueron la hialinización y la fragmentación de las fibras de colágeno (34%), neovascularización en 40.3%, y la disposición irregular de las fibras elásticas es el cambio más frecuente con 56.7% del total de muestras. Existe una diferencia en la presencia de cambios en el LF, de acuerdo con el diagnóstico, siendo estadísticamente significativo para la fragmentación de las fibras de colágeno (p = 0.045), la degeneración quística (p = 0.001), la apariencia fibrilar (p = 0.007) y la hipercelularidad (p = 0.005) todos ellos, siendo más frecuentes en el grupo LDS. El grupo LHD presentó fragmentación de las fibras de colágeno en 45.5% (p = 0.045) y la apariencia fibrilar en 4.5% (p = 0.009).  Conclusiones:  No hay evidencia de hipertrofia celular en los análisis histopatológicos, el engrosamiento del LF se puede ver por abultamiento del mismo, seguido de colapso del segmento de movimiento.]]></p></abstract>
<kwd-group>
<kwd lng="en"><![CDATA[Ligamentum flavum]]></kwd>
<kwd lng="en"><![CDATA[hypertrophy]]></kwd>
<kwd lng="en"><![CDATA[thickness]]></kwd>
<kwd lng="en"><![CDATA[lumbar pathology]]></kwd>
<kwd lng="en"><![CDATA[spinal stenosis]]></kwd>
<kwd lng="es"><![CDATA[Ligamentum flavum]]></kwd>
<kwd lng="es"><![CDATA[hipertrofia]]></kwd>
<kwd lng="es"><![CDATA[espesor]]></kwd>
<kwd lng="es"><![CDATA[patología lumbar]]></kwd>
<kwd lng="es"><![CDATA[estenosis espinal]]></kwd>
</kwd-group>
</article-meta>
</front><back>
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