Technologies Found to Enable Precision, Accuracy in Pedicle Screw Placement

A study at Hospital for Special Surgery (HSS) comparing robotic-assisted navigation to the use of augmented reality in spine surgery found that both techniques demonstrate excellent accuracy and safety for pedicle screw placement. The research was published online ahead of print by the journal Spine.

Many spinal surgeries require the use of pedicle screws to stabilize the spine, and precise positioning is critical for a successful surgery.

“Compared to conventional free-hand techniques, both robotic-assisted navigation and the use of augmented reality have demonstrated superior accuracy,” said Darren R. Lebl, MD, MBA, a spine surgeon and director of research at HSS, and principal investigator of the study.  “Our study is the first to directly compare [robotic-assisted navigation] to [augmented reality] with respect to screw placement precision.”

Technology Becoming More Common

Over the last decade, numerous robotic-assisted navigation and augmented reality systems designed for spine surgery have emerged.

“In addition to enhanced accuracy, the potential advantages of both technologies include reduced radiation exposure and provide for improved safety in spine surgery,” Dr. Lebl said. “A growing number of major medical centers nationwide are using at least one of these technologies.”

Robotic-assisted navigation involves robotic guidance of surgeon-operated instruments. A robotic arm, along with 3D images of the patient’s anatomy and navigation technology similar to GPS, enables the surgeon to perform a minimally invasive procedure that is planned ahead of time on advanced software.

Augmented reality-assisted spine surgery superimposes 3D images of a patient’s anatomy onto the surgeon’s visual field during surgery via an augmented reality headset. A preoperative CT scan of the patient’s spine is used to plan and perform the surgery.

Study Findings

The HSS study included 212 adult spine surgery patients who had a total of 1211 pedicle screws placed using either robotics (108 patients received 827 screws) or augmented reality (104 patients received 384 screws) between June 2020 and October 2023.

These patients had undergone surgery in the lumbar and/or sacral spine for degenerative spinal conditions. One experienced surgeon performed all of the robotic cases, while 2 other experienced spine surgeons used the augmented reality system.

The position of each pedicle screw was assessed after surgery based on either CT scan or 3D fluoroscopy using the Gertzbein-Robbins classification system, which assigns a grade of A, B, C, or D to evaluate accuracy.

The HSS researchers considered Grades A and B to be acceptable. The A rating is assigned to screw placement completely within the pedicle. Grade B, still acceptable, is assigned to a screw that is 2 mm outside the desired location. In this study, any screw with a Grade C or D would be deemed unacceptable.

After surgery, 2 independent spine surgeons assigned a grade to all the pedicle screws. No significant difference was found between robotic-assisted navigation and augmented reality screw placement in terms of accuracy, with 99.6% of robotic-assisted navigation screws rated as Grade A or B, and 98.7% of augmented reality screws classified as A or B. Overall, 92.6% of the screws achieved the top Grade A rating.

Future of Spine Surgery

“Our results confirmed excellent accuracy for both techniques, making both robotics and [augmented reality] safe tools for accurate positioning of lumbosacral pedicle screws,” Dr. Lebl said. “However, a higher rate of Grade A screws was seen in the [robotic-assisted navigation] group, potentially highlighting superior precision for robotics.”

Dr. Lebl believes the study represents the future of spine surgery.

“Our team at HSS is working to advance spine surgery to make it safer, less invasive and more precise, with less radiation exposure,” he explains. “Our team has already implemented spine surgery with real-time confirmation of implant accuracy in the operating room so that everything is optimally positioned before the patient goes to the recovery room.

“In the future, more focus will be on decisions regarding the timing and type of surgery, and the actual execution of the surgery will become much more automated.”

Source

Altorfer FCS, Kelly MJ, Avrumova F, et al. Pedicle screw placement with augmented reality versus robotic-assisted surgery. Spine (Phila Pa 1976). 2024 Sep 4. doi: 10.1097/BRS.0000000000005147. Online ahead of print.

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