**4.1 Robotic-assisted transforaminal lumbar interbody fusion**

Transforaminal lumbar interbody fusion (TLIF) allows for circumferential fusion, restoration of disc space height, and both direct and indirect neural decompression. Open TLIF has been associated with significant early postoperative morbidity secondary to extensive muscle retraction and dissection, which may result in increased postoperative pain, decreased mobility, and impaired overall function [47, 48]. In response to the limitations of open TLIF, the MI-TLIF was developed and has been shown to cause less postoperative pain, faster recovery, shorter hospitalization, and comparable functional outcomes to the open TLIF [49–51].

Traditionally, pedicle screws were placed percutaneously under fluoroscopic guidance for the MI-TLIF, resulting in potentially decreased accuracy and increased radiation exposure, as discussed in previous sections of this chapter. Until recently, the integration of spinal robotics into MI-TLIF has largely been confined to facilitating pedicle screw placement, and previous studies have reported on the feasibility and integration of robotics into the MI-TLIF workflow as well as the high pedicle screw placement accuracy [52–54]. Comparative studies assessing broader benefits of spine robot utilization versus traditional fluoroscopic or 3D navigation are lacking in the literature. De Biase et al., compared robot-assisted versus fluoroscopy-guided MI-TLIF procedures and reported no difference in operative time [55]. The study was limited by lack of comparative radiation, radiographic or functional outcomes between the two treatment groups [55].

A previous limitation of robotic MI-TLIF, as compared to 3D navigation, was that older robotic platforms did not allow for real-time navigation outside of pedicle screw placement. However, newer robotic software platforms now enable pre−/ intra-operative planning and navigation for tube placement, interbody cage placement, and disc space preparation (**Figure 1**). Evidence-based benefits of these real-time navigated features have yet to be established in the spinal literature. As robotic integration into MI-TLIF procedures continues to evolve and expand, further research is needed to investigate the possible additive benefit with regards to instrumentation accuracy, operative efficiency, radiation exposure, clinical outcomes, and fusion rates.

## **4.2 Robotic-assisted lateral and oblique lumbar interbody fusion**

Lateral lumbar interbody fusion (LLIF) and oblique lumbar interbody fusion (OLIF) are minimally invasive techniques that can avoid some of the risks associated with anterior or posterior interbody approaches to the spinal column. Traditionally, after the interbody device is placed in LLIF and OLIF procedures in the lateral position, the patient is "flipped" to the prone position for pedicle screw instrumentation and posterior stabilization. Recent studies have begun to investigate the placement of posterior instrumentation in the lateral position, to avoid the "flip," and initial studies have demonstrated improved operative efficiency, less blood loss, and less postoperative ileus with single position lateral circumferential fusions [56].

One of the challenges of performing MISS posterior fixation in the lateral position is pedicle screw instrumentation. Interpreting fluoroscopic imaging, establishing accurate navigation, and the ergonomics of placing the down-sided pedicle screws can be difficult. Placement of robot-assisted pedicle screws in these procedures may offer a significant advantage as the robotic arm acts as a steady holding device, locking the trajectory of the planned pedicle screw, and thereby mitigating

### **Figure 1.**

*Intraoperative planning using a spine robot's integrated navigation platform. This particular platform allows for intraoperative planning of pedicle screw trajectories, diameter, and length. Additionally, interbody placement can be planned, and navigated instruments can allow for targeted intraoperative disc preparation prior to interbody cage placement. Lastly, tube trajectories (if applicable) can also be planned.*

some of the ergonomic challenges of placing these screws. The accuracy of pedicle screws with robot-assistance in the lateral position has been recently investigated and initial studies demonstrate 98% accuracy [57]. Images demonstrating this technique are shown in **Figure 2**.

As described in the MI-TLIF section, the latest iterations of software in some spinal robotics systems can allow for real-time navigation during tube placement, interbody cage placement, and disc space preparation. An additional benefit in the lateral or oblique position is that the robotic arm can be used to stabilize the retraction system, avoiding the need for a table mounted retractor (**Figure 3**). As these are all relatively recent advancements for robot-assisted LLIF and OLIF procedures, studies demonstrating a clinical benefit have yet to be performed.

### **4.3 Robotic-assisted MISS deformity correction**

The majority of research on MISS has focused on addressing degenerative pathology, but as MISS continues to evolve, the utilization of MISS principals to address adult spinal deformity, without compromising outcomes, continues to be investigated. The traditional goals of adult spinal deformity surgery encompass restoration of sagittal and/or coronal balance, adequate neural element decompression, and achieving a solid arthrodesis. These goals may be achieved through MISS techniques – for example, lordosis can be restored through anterior column realignment procedures such as the LLIF and OLIF or posterior-based procedures such as MI-TLIF. Fixation can of course be achieved through percutaneous pedicle screw placement [58, 59]. In multi-level constructs, robotic assistance may have a cumulative benefit as the time saved at each subsequent level will have an additive benefit in longer deformity constructs. As discussed above, the use of a spinal robot may assist in executing these MISS procedures, just as is the case for patients with primarily degenerative pathology. However, evidence demonstrating the additive benefit of robotic-technology in MISS deformity procedures is sparse.

*Robotic Guided Minimally Invasive Spine Surgery DOI: http://dx.doi.org/10.5772/intechopen.97599*

### **Figure 2.**

*Intraoperative placement of pre-planned pedicle screws for a multilevel lateral lumbar interbody fusion. In this image the down-sided pedicle screws are being placed based on the planned trajectory. The stabilized robotic arm facilitates the challenging placement of these screws, eliminates the need for interpretation of fluoroscopic imaging in the lateral position and improves the overall ergonomics and ease of placing these screws.*

### **Figure 3.**

*The intraoperative navigation platform for this spine robot is used to plan the interbody placement in a multilevel lateral lumbar interbody fusion (A). The spine robot arm is then used to localize the trajectory of the planned retractor placement and the stabilized arm can be used to secure the retractor, avoiding the need for a table-mounted retractor (B).*

One aspect of area robotic utilization within the field of adult spinal deformity that has received research interest is the safe and accurate placement of pelvic screw fixation. MISS percutaneous pelvic screw fixation using traditional fluoroscopy allows for less soft tissue dissection, as compared to the traditional open technique, which may result in a quicker recovery and less postoperative complications [60]. The additive use of robotic-assistance allows for preoperative planning, may increase accuracy, and decrease the technical difficulty in placing MISS pelvic fixation. A recent study demonstrated high accuracy with no intra- or postoperative complications using robotic-assistance for pelvic screw fixation in adult deformity patients [61].
