Ok,

having looked at the site I would recommend that the changes are done via server side. I assume the htaccess file is been used to to parse category/subcategory/productname to a controller. Within that controller if the product is found clean the product name with the function below test it against the given url and do a 301 redirect to the cleaned name if they do not match

function clean_name($string) {    $non_acceptable = '#[^-a-zA-Z0-9 ]#';    $string = preg_replace($non_acceptable, '', $string);    $string = trim($string);     $string = preg_replace('#[-_ ]+#', '-', $string);     return $string;  }

I have 1 or two suggestions. Could you provide an example of the URL? This will allow me to give a more definiive  solution