Background: Preoperative planning software and a robotic device facilitate the placement of pedicle screws, especially in patients with difficult anatomy, thereby increasing the feasibility, accuracy, and efficiency of the procedure. The robot functions as a semiactive surgical assistive device whose goal is not to substitute but to offer the surgeon a set of versatile tools that can broaden his or her ability to treat patients 1 . Description: The robotic guidance system consists of a bed-mounted surgical arm and a workstation. We used the Mazor X Stealth Edition Robotic Guidance System by Medtronic for spine surgery, which has been previously described 2–5 . Unlike other systems that are navigation-based and require an optical tracking mechanism, this system relies on the preoperative plan to be referenced using the intraoperative registration. The workstation runs an interface software that facilitates preoperative planning, intraoperative image acquisition and registration, kinematic calculations, and real-time robot motion control. The robotic arm is mounted onto the bed as well as rigidly attached to the patient’s spine. It can move in 6 degrees of freedom to provide the preplanned screw trajectory and entry point thereby allowing the surgeon to manually perform the drilling and screw insertion through either an open or percutaneous procedure by first seating a drill tube and then drilling and tapping the hole as needed. Alternatives: Other robotic systems include the ROSA robot by Medtech, the ExcelsiusGPS robot by Globus Medical, and the SurgiBot and ALF‐X Surgical Robotic systems (both from TransEnterix). The Da Vinci Surgical System (Intuitive Surgical) has been utilized for laparoscopic anterior lumbar interbody fusion (ALIF), but it has not been approved by the U.S. Food and Drug Administration for actual spinal instrumentation. Alternative surgical techniques for pedicle screw placement include the freehand fluoroscopy-guided technique and intraoperative image-assisted computer navigation techniques, including isocentric C-arm (Iso-C) 3D (3-dimensional) navigation (Siemens), computed tomography (CT) navigation, O-arm navigation (Medtronic), CT-magnetic resonance imaging co-registration technology, and a 3D-visual guidance technique 6–8 . Rationale: The robotic-guided pedicle screw placement offers the following benefits over conventional dorsal instrumentation techniques: improved accuracy and safety in pedicle screw insertion 2–4,9–13 ; precision in screw size selection and planned screw positioning 2 ; a reduction in exposure to radiation for the surgeon, the patient, and the operating-room staff 9,11,12,14–19 ; simplicity and user-friendliness with a moderate learning curve 10,11,20,21 ; ease of registration and reduction of operating time 2 ; significant enhancement of the surgeon’s ergonomics and dexterity for repetitive tasks in pedicle screw placement 15,22–24 ; and a wider coverage in function to include utilization during minimally invasive surgery where applicable 11,25 . Expected Outcomes: Accuracy rates between 94.5% and 99%, comparable with those in our study 10 , have been reported with the robotic-guided pedicle screw insertion technique, even in studies involving complex deformities and revision surgeries for congenital malformations, degenerative disorders, destructive tumors, and trauma 2–4,9–13 . The safety of this technique, in terms of reduced complications and intraoperative radiation exposure, has also been documented as higher than that for freehand fluoroscopic guidance or other navigation techniques 9,11,12,14–19 . The feasibility of this procedure has been further extended to minimally invasive procedures and to use in the cervical region, with replication of its advantages. It is associated with a reasonable learning curve, with consistent successful results after 25 to 30 patients. Important Tips: The principles of robotic-guided pedicle screw placement are similar irrespective of the system used.Although initially utilized mainly for thoracolumbar pedicle screw insertion, the latest robots and software have been adapted for use in the cervical spine with equivalent efficiency and accuracy.Robotic guidance can be employed in non-pedicle-screw-insertion procedures.Challenges include radiation exposure, trajectory failure, equipment and software failure, failed registration, logistics, time, and high cost.

Study Design. Systematic review. Objective. The aim of this review is to present an overview of robotic spine surgery (RSS) including its history, applications, limitations, and future directions. Summary of Background Data. The first RSS platform received United States Food and Drug Administration approval in 2004. Since then, robotic-assisted placement of thoracolumbar pedicle screws has been extensively studied. More recently, expanded applications of RSS have been introduced and evaluated. Methods. A systematic search of the Cochrane, OVID-MEDLINE, and PubMed databases was performed for articles relevant to robotic spine surgery. Institutional review board approval was not needed. Results. The placement of thoracolumbar pedicle screws using RSS is safe and accurate and results in reduced radiation exposure for the surgeon and surgical team. Barriers to utilization exist including learning curve and large capital costs. Additional applications involving minimally invasive techniques, cervical pedicle screws, and deformity correction have emerged. Conclusion. Interest in RSS continues to grow as the applications advance in parallel with image guidance systems and minimally invasive techniques. IRB Approval. N/A.

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OBJECTIVE There are few prior reports of acute pelvic instrumentation failure in spinal deformity surgery. The objective of this study was to determine if a previously identified mechanism and rate of pelvic fixation failure were present across multiple institutions, and to determine risk factors for these types of failures. METHODS Thirteen academic medical centers performed a retrospective review of 18 months of consecutive adult spinal fusions extending 3 or more levels, which included new pelvic screws at the time of surgery. Acute pelvic fixation failure was defined as occurring within 6 months of the index surgery and requiring surgical revision. RESULTS Failure occurred in 37 (5%) of 779 cases and consisted of either slippage of the rods or displacement of the set screws from the screw tulip head (17 cases), screw shaft fracture (9 cases), screw loosening (9 cases), and/or resultant kyphotic fracture of the sacrum (6 cases). Revision strategies involved new pelvic fixation and/or multiple rod constructs. Six patients (16%) who underwent revision with fewer than 4 rods to the pelvis sustained a second acute failure, but no secondary failures occurred when at least 4 rods were used. In the univariate analysis, the magnitude of surgical correction was higher in the failure cohort (higher preoperative T1-pelvic angle [T1PA], presence of a 3-column osteotomy; p < 0.05). Uncorrected postoperative deformity increased failure risk (pelvic incidence–lumbar lordosis mismatch > 10°, higher postoperative T1PA; p < 0.05). Use of pelvic screws less than 8.5 mm in diameter also increased the likelihood of failure (p < 0.05). In the multivariate analysis, a larger preoperative global deformity as measured by T1PA was associated with failure, male patients were more likely to experience failure than female patients, and there was a strong association with implant manufacturer (p < 0.05). Anterior column support with an L5–S1 interbody fusion was protective against failure (p < 0.05). CONCLUSIONS Acute catastrophic failures involved large-magnitude surgical corrections and likely resulted from high mechanical strain on the pelvic instrumentation. Patients with large corrections may benefit from anterior structural support placed at the most caudal motion segment and multiple rods connecting to more than 2 pelvic fixation points. If failure occurs, salvage with a minimum of 4 rods and 4 pelvic fixation points can be successful.