If query parameters in the request looks like this

/something.cgi?param_name=1&param-name=2

I can access 'param_name' as $arg_param_name. How do I access 'param-name' though? $arg_param-name will not work since as far as nginx is concerned the variable name ends at $arg_param. Is there a workaround for this case? Has anyone else run into a similar problem?