// Preparo previamente la consulta
$courseQuestionsByPeriodQuery = $mysqli->prepare('CALL getCourseQuestionsByPeriod(?,?)');

foreach($courses as $courseid){
	// Asi no funciona utilizando la consulta preparada previamente
	$questions = array();
	$params = array($courseid, $periodid);
	$results = array('questionId', 'topicName', 'questionDescription', 'questionLevel', 'questionStatus', 'userName', 'userCode', 'userLastname', 'userFirstname', 'topicLength');
	ExecutePreparedCallableStatement($courseQuestionsByPeriodQuery, 'ii', $params, $results, function($results) use (&$questions){
		$question = array();
		foreach($results as $key => $value){
			$question[$key] = trim($value);
		}
		$questions[] = $question;
	});

	// De esta manera funciona sin usar la consulta preparada previamente, pero podria causar que llegue al limite de consultas preparadas permitidas
	$questions = array();
	$params = array($courseid, $periodid);
	$results = array('questionId', 'topicName', 'questionDescription', 'questionLevel', 'questionStatus', 'userName', 'userCode', 'userLastname', 'userFirstname', 'topicLength');
	ExecutePreparedCallableStatement('CALL getCourseQuestionsByPeriod(?,?)', 'ii', $params, $results, function($results) use (&$questions){
		$question = array();
		foreach($results as $key => $value){
			$question[$key] = trim($value);
		}
		$questions[] = $question;
	});
}