Dissection of C2 Guiding to C1 Lateral Mass and Facilitation of Screw Placement: Technical Note

Surgical intervention at the craniovertebral junction requires preoperative and intraoperative planning to get optimum postoperative results. Careful positioning minimizes the risk of iatrogenic injury and can also facilitate adequate surgical exposure. Tortuous venous channels that are usually encountered as the dissection proceeds may cause excessive bleeding before reaching the lateral mass (LM). However, both localization and placement may be made easier by altering the dissection technique and modifying the patient's position. Traditionally, the military tuck position is described for the dorsal approach to the craniovertebral junction. The objective of this study is to emphasize the role of arc or bow like position, a modification of prone position for adequate placement of C1 LM screw in these cases. We operated on 68 patients with atlantoaxial dislocation in an arc or bow position from January 2013 to September 2018. In 58 patients, at least 1 C1 LM screw was placed. This position helped in easy and early recognition with easy trajectory for the C1 LM screw placement and less work force. Visual axis to the lateral mass of C1 in an arc/bow position with head elevation puts C1 LM more in the visual axis of the operator, which makes the trajectory straight without causing much angulation while inserting the screw. At the same time, the axis vertebra guides the surgeon to the C1 lateral mass with no handling of dura.