Endoscopic surgical techniques have been applied to the spine with varying degrees of success. In the early 1990s, laparoscopic techniques were used for spinal fusion of the lumbosacral disc. Using retroperitoneal balloons for exposure, endoscopic techniques were also used in the lumbar spine to access the lumbar discs above L5-S1. Discectomies and anterior interbody fusions are performed through working portals. There was a steep learning curve. The overall success rate was less than that for the conventional mini-open procedure, the complication rates were higher and this technique fell out of favor.