We can define minimally invasive surgery (MIS) as a procedure that allows less extensive manipulation of surrounding tissues than a conventional open one while accomplishing the same goals and objectives at the target structure. In spine surgery, minimal access surgery for the treatment of lumbar disc disease is by no means a new concept; many procedures have been developed for the purpose of achieving a less destructive surgery: percutaneous laser disc decompression (1,2); percutaneous endoscopic laser discectomy (3); percutaneous nucleotomy (4,5). Endoscopic discectomy was proposed in 1997 by Foley and Smith (6) to allow a decompression of a nerve root even in the case of bony decompression with minimal tissue trauma through a direct visualization of the structures.

Minimally invasive surgery also found an application in reducing tissue damage in fusing procedures that, when performed in open surgery, are associated with lengthy hospital stays (intense postoperative pain), significant costs (7), and not marginal morbidity for patients caused by the muscle dissection and retraction and soft tissue injury occurring during standard lumbar fusion procedures (8,9,10). Kahanovitz et al. reported that in a long-term strength assessment postoperatively of patients who had undergone back surgery, “every strength parameter tested except male isokinetic flexion strength showed at least a 30% decrease when compared with normal values” (11).

In light of the evidence, we consider muscle damage a possible cause of long-term postoperative back pain, which may be due to vertebral instability of the adjacent segments as consequence of the decrease in muscle strength.

We present our experience with a minimally invasive spine procedure that allows a posterior stabilization of the vertebral segments through only two small, symmetric, paravertebral wounds. This technique is based on standard spinal techniques but moves beyond them to minimize iatrogenic injury (avoiding stripping and cutting muscles) while still achieving the traditional goals of spinal surgery.

Analyzing the surgical steps, the first one is represented by the individuation of some surgical landmarks (Fig. 21.1): Then, under radioscopic guidance (A-P and L-L control), the trocar is introduced in the pedicle (Fig. 21.2). After tissue dilatation (Fig. 21.3), the pedicle is prepared for the screw and the first screw is placed.