I suspect you want something like this:

<xsl:for-each select="//*[matches(., concat('\W', $term, '\W'), 'im')]">
  <xsl:sort select="count(ancestor::node())" order="descending"/>
  <xsl:if test="position()=1">
    <path>/<xsl:value-of select="saxon:path()"/></path>
  </xsl:if>
</xsl:for-each>

Michael Kay
http://www.saxonica.com/