Minimally invasive spinal surgery: a historical perspective.

The concept of minimally invasive spinal surgery embodies the goal of achieving clinical outcomes comparable to those of conventional open surgery, while minimizing the risk of iatrogenic injury that may be incurred during the exposure process. The development of microscopy, laser technology, endoscopy, and video and image guidance systems provided the foundation on which minimally invasive spinal surgery is based. Minimally invasive treatments have been undertaken in all areas of the spinal axis since the 20th century. Lumbar disc disease has been treated using chemonucleolysis, percutaneous discectomy, laser discectomy, intradiscal thermoablation, and minimally invasive microdiscectomy techniques. The initial use of thoracoscopy for thoracic discs and tumor biopsies has expanded to include deformity correction, sympathectomy, vertebrectomy with reconstruction and instrumentation, and resection of paraspinal neurogenic tumors. Laparoscopic techniques, such as those used for appendectomy or cholecystectomy by general surgeons, have evolved into procedures performed by spinal surgeons for anterior lumbar discectomy and fusion. Image-guided systems have been adapted to facilitate pedicle screw placement with increased accuracy. Over the past decade, minimally invasive treatment of cervical spinal disorders has become feasible by applying technologies similar to those developed for the thoracic and lumbar spine. Endoscope-assisted transoral surgery, cervical laminectomy, discectomy, and foraminotomy all represent the continual evolution of minimally invasive spinal surgery. Further improvement in optics and imaging resources, development of biological agents, and introduction of instrumentation systems designed for minimally invasive procedures will inevitably lead to further applications in minimally invasive spine surgery.