Learning curve in robot-assisted spinal fusion may be associated with inferior outcomes

Seniro author Peter G Passias

The use of robots to assist in spinal surgery carries a higher complication burden in the introductory phase as surgeons overcome the learning curve associated with the technology, according to a study presented at the 27th Annual Meeting on Advanced Spine Techniques (IMAST 2020) looking at robot-assisted lumbar interbody fusions. The findings were presented by Waleed Ahmad (NYU Langone Medical Centre, New York, USA), who along with the study’s principal author Peter Passias, concluded that robot-assisted lumbar interbody fusions were associated with inferior perioperative and one-year post-operative outcomes, including longer operating times, urinary and intraoperative complications compared to unassisted surgery.

“The recent ballooning of the medical device industry has brought forth key advancements to the field of spine surgery. Robot-assisted surgical techniques are being increasingly implemented to increase surgeon accuracy and stamina,” Ahmad said in the introduction to his presentation. However, he added: “further investigation of the introductory phase of robotic techniques on surgical outcomes remains warranted”. Through their study, Ahmad and colleagues set out to identify differences in outcomes and complication rates between robot-assisted and unassisted lumbar interbody fusions, and to determine the presence of a learning curve with regard to individual surgeon caseload.

Ahmad commented that the incorporation of robotic technology into spinal surgery has yielded the necessity for surgeons to adapt and learn new techniques before understanding their true impact on clinical outcomes. “For example,” he said, “the utilisation of robot-assisted pedicle screw fixation during lumbar fusions aims to decrease complications associated with misplaced screws, while also supporting innovative, minimally invasive surgical techniques. However, the literature remains mixed in its conclusions on whether robot-assisted spine surgery will lead to improved surgical outcomes or result in an increased operative time, length of stay, and radiation exposure”.

To test this statement, Ahmad and colleagues conducted a retrospective clinical review of patients undergoing lumber interbody fusion at their centre from 2012 to 2018. Patients included in the study were aged over 18 years, undergoing lumbar interbody fusion and had available preoperative, operative, anaesthetic and baseline follow-up up to one year. Patients with a primary diagnosis of malignancy, trauma or infection were excluded.

Operative and complication information were collected following the surgery, including operative time, estimated blood loss, surgical approach and length of stay. Surgical data were grouped by absence or presence of robotic assistance during the operation. The study team performed descriptive analysis describing differential rates of robotic assistance per surgeon, and univariate analyses identifying differences in rates or perioperative outcomes and rates of intraoperative and post-operative complications. Sub-analysis by individual surgeon identified trends in outcomes for introductory, robotic-assisted lumbar interbody fusion cases, which were defined as the first 100 cases.

In total 1,267 LIF patients were found to be eligible for study, with an average age of 57 years, 51.7% were female with an average BMI of 29.5. The majority (60.5%) of these patients underwent a transforaminal lumbar interbody fusion (TLIF) followed by 24.6% who underwent anterior lumbar interbody fusion (ALIF) and 12.7% who underwent lateral lumbar interbody fusion (LLIF).

The study team found that there were no significant differences in superficial or deep surgical site infections or return to OR at 30 or 90 days; however, Ahmad noted that a sub-analysis by surgeon revealed that introductory robotic cases had higher operative times, greater estimated blood loss and longer length of stay than those performed unassisted. Also, introductory cases for the majority of surgeons had higher rates of complications, including urinary complications, ileus and intraoperative complications including durotomy, Ahmad said.

Summing up the findings, he said: “In conclusion we found that robotic assisted lumbar interbody fusions, especially the introductory cases, were associated with inferior perioperative and one-year post-operative outcomes, including longer operative times, urinary complications and intraoperative complications. Overall, we find that robotic technology may carry a higher complication burden in the introductory phase as surgeons overcome the learning curve dynamic. As surgeons adjust to the implementation of robotics and increase case volume, future studies may show improvement in complication rates and superior patient reported outcomes.”


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