A device for dilating an ostium of a paranasal sinus of a human or animal subject may include: a handle; an elongate shaft having a proximal end coupled with the handle and extending to a distal end; a guidewire disposed through at least a portion of the shaft lumen; a dilator having a non-expanded configuration and an expanded configuration; and a slide member coupled with at least one of the guidewire or the dilator through the longitudinal opening of the shaft for advancing the guidewire and/or the dilator relative to the shaft.