An improved radial expansible retractor and a method of minimally invasive surgery, by opening a channel in the brain or other soft tissue of a patient, by inserting the radial expansible retractor into the body of the patient, and by widening the channel at a continuous and gentle rate. The use of the improved radial expansible retractor renders surgical procedures, including neurosurgical procedures, shorter, less traumatic, and more reliable, reducing risk and the need for subsequent surgery and reducing recovery time. Procedures are carried out with real time monitoring of the retracted brain perfusion pressure. A plurality of improved radial expansible retractors may be used in a single operation. The improved radial expansible retractor allows access to areas of the brain previously almost impossible to access.