The Mazor Spine Assist system was the first CE- and FDA-approved system for instrumented spine surgery. The Renaissance is the updated version of preexisting Spine Assist. The systems consist of a miniature construction with two discs connected by six linear actuators. The lower disc is connected to a mounting platform, while the upper disc can be connected to extension arms, which can hold instruments. This semi-active robotic spine surgery system indicates the direction of pedicle screw trajectories and can be used for all tasks requiring the cannulation of bone throughout the thoracic, lumbar, and sacral spine (Fig. 3.1).

Spine surgery with Renaissance consists of four basic steps: preoperative plan, mount, 3D synchronization, and surgery. The first step starts before entering the operating room with a preoperative planning on a computer or the robot console in the operating room. The patient’s CT scan is uploaded to create a 3D model of the patient’s spine. Trajectories can be planned in axial, coronal, and sagittal views. The software provides a multitude of visualization options warranting ample opportunity to plan screw angle and rod alignment. Intraoperatively, the patient is in prone position as usual. In order to obtain optimal registration results, no radio-opaque covering, cables, and monitoring equipment should be lying over or around the operated segments.

Prior to the registration and referencing procedure, the surgeon can choose any of three options to mount the system in the operating field which require a different disposable instrument kit:

In order to indicate the mounting platform special location on fluoroscopy, a 3D marker is attached onto it. Two fluoroscopic images of the 3D marker and spine are taken in AP and oblique views. The software then automatically matches the intraoperative images to the corresponding locations on the preoperative CT and registers and synchronizes the CT base surgical blueprint. Each vertebra is registered separately, independent of anatomical landmarks, so that deformities or previous operations do not affect accuracy. Alternatively, an intraoperative CT scan performed with a reference array can be uploaded in which case fluoroscopy is unnecessary.

To begin the surgical procedure, the surgeon selects the target vertebra from the preoperative plan. The robotic guidance arm is secured to the mounting platform. The robot steers toward the chosen trajectory. After mounting the extension tool, a cannula is inserted. After a stab incision through skin and fascia, the cannula is inserted further until the surface of the bone is reached. The bone surface can be flattened using a “Peteron.” Then, a spiky anchor cannula is inserted after which drilling can be performed. After drilling, a Kirschner wire is inserted, and the extension arm can be removed. The procedure is repeated for all vertebrae. Depending on the image adapter used (9 or 12 in.), only a limited number of vertebrae can be registered in a reference frame. Therefore, for every about three to four segments, a new registration is required.

The Mazor X™ spine assist system is a new platform that was unveiled earlier in July 2016 by Mazor Robotics. This system comprises three main processes, namely, preoperative analysis and surgical planning, intraoperative guidance, and intraoperative 3D verification (Fig. 3.2).

Concerning the first process, a computer application called “X-Align” is used. This module creates by computing, a preoperative analysis, and alignment by measuring the spine and simulating the patient’s anatomy and the tools to use, evaluating how things are lining up, in order to ensure they are used in a correct and precise alignment. Subsequently, a treatment plan is prepared on the basis of the analysis. Then an arm mounted on the surgical table and the patient’s bone is used with a 3D camera optical tracking to accurately guide the tools according to the surgical plan. A real-time 3D verification is used during the procedure to verify the placement using fluoroscopy X-ray, visual tracking, or other imaging systems.

ROSA™ Spine has been developed by Medtech Company and corresponds to an image-guided system, which combines robotic assistance in positioning tools according to planned trajectories and navigation features (Fig. 3.3). This guidance system includes a mobile base with an industrial robot arm with six degrees of freedom. In addition, a full-fledged navigation system with an infrared camera and a touch-screen console serve to track the patient’s movement, plan trajectories intraoperatively, and if necessary, help the surgeon navigate intraoperatively. In contrast to the previously discussed Mazor system, the ROSA spine requires intraoperative 3D imaging. Its software does not allow for 2D referencing, and therefore, preoperative trajectory planning is not possible.

After inserting the iliac crest bolt, 3D imaging is performed (at present, referencing is only possible using the O-arm, but trials using flat-panel fluoroscopy devices are under way).

The surgeon then plans the trajectory of the screws using the console. Thereafter, the ROSA platform with the robot arm is installed to a patient’s side and the surgeon in the opposite side. The navigation platform with camera is placed to patients’ feet. The robot arm guides the surgeon to perform drilling and Kirschner wire analogous to the Mazor system [12].

The AQrate^® system includes a robotic arm and a platform with software (Fig. 3.4). The robotic arm is placed beside the patient and stabilized at the operating table. A steering handle is attached to the end of the robot arm on which standard surgical instruments can be attached. The robotic arm permits through its six-axis force sensor to offer a haptic steering and force feedback. The robot guides the position of the instruments at the entry point and gives the trajectory. Once the instrument in place, the robot holds the path while the surgeon performs the remaining steps by manipulating the steering handle as if he was holding the instrument itself. This device allows a minimally invasive spinal surgery by allowing percutaneous surgery.