The screw can be manually operated to achieve the optimum degree of opening required by the surgeon to remove stillbirth in a patient. The surtex Instruments obstetric Perforators are available in different patterns such as the Nagele perforator
that has wide blades specially designed to perforate the fetal scull to aid delivery of the stillbirth. Another commonly used perforator in obstructed labor is the Smellie perforator
, which has sharper blades, which are longer, designed to reach into the thoracic or the pelvic cavity of the stillbirth to relieve the obstruction.