Minimally invasive spine surgery means the surgeon makes a very small incision and there is as little disruption of the underlying soft tissues as possible. They can do this now because special surgical instruments have been developed just for MISS. Intraoperative microscopes, fluoroscopes (real-time X-rays), and tube-based instruments make it all possible.
The original MISS operations started with needle-like instruments such as the endoscope used for vertebroplasty, kyphoplasty, discectomy, or destroying tumors with radiofrequency. Larger portals openings into the body with the same small incision are now possible with tube-shaped surgical tools.
The tube allows the surgeon to access a larger area underneath the incision, take photos inside the body at the operative site, and even allow for more extensive surgeries that would have needed an open incision before tubular retractors were developed. Retractors help hold the skin and underlying soft tissues open to give the surgeon access to the intended surgical area.
Like many other things in our world, improved technology is what has really made the difference. Moving from open procedures with large incisions to these smaller, minimally invasive methods will continue to change and progress. The future of robotics, distant surgeries, and more highly developed microscopic instruments with real-time computer-assisted operations is already here.