1.  Field of the Inventive Concepts
The inventive concepts disclosed and claimed herein relate generally to surgical instruments, and more particularly, but not by way of limitation, to a surgical instrument for introducing a rod into a body and placing the rod in a minimally invasive manner. 
2.  Brief Description of Related Art
Traditional open surgical procedures in locations deep within a patient's body can result in extensive tissue traumatization, which in turn leads to prolonged recovery time and increased risk of infections.  To reduce such trauma, laparoscopic surgical devices, remote-control instrument manipulation, minimal incision procedures, and the like have been developed.  Such “minimally invasive” surgical procedures are especially desirable for spine surgeries because spine pathologies are located deep within the body without clear muscle planes, and there is danger of damaging the adjacent neural and vascular tissues. 
Spine surgery often involves use of connecting elements, such as rods, screws, plates, or wires, which are placed and fixed between two or more locations of the spine.  For example, spinal fixation is a neurosurgical procedure in which two or more vertebrae are anchored to each other to reduce vertebral mobility and to avoid potential damage to the spinal cord.  Numerous spinal fixation devices and designs have been developed, but they typically all include combinations of rods, plates, and screws, and these devices must be transported through significant tissue without causing extensive tissue traumatization. 
Placement of these connecting elements remains a challenging step in spine surgery, often requiring multiple incisions.  Further difficulties arise due to the angle variation between, for example, an initial vertical insertion trajectory for a stabilization rod, and the desired final horizontal position of the rod. 
In view of the foregoing, there is a need for surgical tools and methods that can avoid multiple incisions for rod insertion.  There is also a need for surgical instruments that can provide a controlled rod insertion by allowing for changes in rod angulation with respect to the holding tool.  It is to such a surgical instrument that the presently disclosed and claimed inventive concepts are directed.