1.  Technical Field
The technical field relates to balloon dissectors for forming an anatomical space within a body, to cannulas having balloon anchors, and to apparatus having a combined balloon dissector and balloon tip cannula. 
2.  Background of Related Art
During various surgeries, it is necessary to dissect tissue layers to form an anatomical space within which surgical instruments may be manipulated.  For example, in hernia repair surgery, it is necessary to form an anatomical operative cavity within the extraperitoneal space in order to dissect fascia tissue layers and access the hernia site.  Various balloon dissectors are known for performing the tissue dissection procedure used in hernia repair surgery.  These generally include a single device having a dissection balloon formed on the distal end of a tube and an inflation port formed on the proximal end of the tube.  The balloon dissector is inserted into an incision and the balloon is inflated for dissection.  After dissection and after removing the balloon dissector from the incision, a cannula is inserted into the incision and used to insufflate while forming an access passageway for the introduction of surgical instruments into the anatomical space. 
While the currently known tissue dissection devices and cannulas are useful, improvements are desirable.  It would be beneficial to have a balloon dissector device combined with a balloon tip cannula.