With this technique we did not experience major complications related to wrong screw placement www.selleckchem.com/products/17-AAG(Geldanamycin).html except for a small incidence of uneventful violation of the cortical of the pedicle (2 for open and 4 for percutaneous). Park et al. using similar fluoroscopic guided technique reported very low screw malpositioning rates in their series of 172 screws postoperatively verified by CT [6]. If the tip of the screw remains lateral to the medial pedicle wall until the engagement of the vertebral body, it is highly improbable that it can cause a canal encroachment. It may be argued that various navigation systems have been developed to reduce pedicle screws misplacement. Lieberman et al. reported that the use of robot guidance system increases the accuracy of percutaneous pedicle screw placement thereby reducing radiation exposure and procedure time [7], compared to the control group.

They concluded that this advanced technology might also allow inclusion of patients with complicated anatomic deformities. Kakarla et al. treated percutaneously six patients affected by thoracic fractures (five acute unstable thoracic fracture and one osteoporotic burst fracture) with the assistance of intraoperative Iso-C C-arm fluoroscopy [8]. Accuracy of screw placement was investigated by postoperative CT scan according to the method of Youkilis et al. [2]. They concluded positively about the feasibility of percutaneous stabilization of complex spinal fracture with the aid of neuronavigation. Undoubtedly the accuracy of the screw-navigated placement is higher in comparison with other ��free-hand�� techniques, but unfortunately the cost of navigation systems is often prohibitive.

Even without a sophisticated pedicle screw-navigation system, neither our percutaneous technique nor our open ��free-hand�� technique was associated with intraoperative complications. Open ��free-hand�� pedicle screw insertion, guided by recognizable anatomical landmarks, is widely used at present, particularly for spinal deformities, even in the upper thoracic spine given the superiority of these constructs over hook constructs in terms of coronal and axial correction [9]. In the present series we experienced no difficulty using this technique in the upper thoracic spine, where percutaneous screw insertion would have been less feasible and more dangerous.

Although the limits of this work are the low number of patients and the short time of the outcome, we believe that they do not represent, however, a major limitation. In fact, the main purpose of our study was to verify the possibility to extend to the thoracic spine the advantages of minimally invasive procedure in the treatment of instability AV-951 diseases in the same way we do in the lower spine. In this first phase of the study, we selected a limited number of patients that were eligible for less invasive approach with long stabilization.