General Session: Tumor, Trauma, Infection, Image

Presented by: H-J. Kim - View Audio/Video Presentation (Members Only)

Author(s):

H-J. Kim(1)

(1) Seoul National University Medical College and Seoul National University Bundang Hospital, Orthopaedic Surgery, Bundang, Korea, Republic of

Abstract

Background: In application of minimally invasive surgical (MIS) approaches for instrumented spine surgery, robot-assisted MIS has been proposed to further improve surgical outcomes while overcoming the limitations of the MIS approach. However, a recent randomized controlled trial has shown conflicting results.

Purpose: To compare the accuracy and safety of an instrumented posterior lumbar interbody fusion (PLIF) performed using a robot-assisted minimally invasive (Rom-PLIF) or a conventional open approach (Cop-PLIF).

Study Design: Prospective randomized controlled trial (NCT02121249).

Patient Sample: Patients with degenerative lumbar disease.

Outcome Measures: Radiological accuracy and perioperative outcomes including surgical time from skin to skin, length of hospital stay, complication rates, time to return to ambulation, and radiation exposure.

Methods: Thirty-seven and forty-one patients to undergo an instrumented PLIF procedure were randomly assigned to be treated using a Rom-PLIF and a Cop-PLIF, respectively. Radiological accuracy and perioperative outcomes including surgical time from skin to skin, length of hospital stay, complication rates, time to return to ambulation, and radiation exposure were analyzed. For intra-pedicular accuracy of pedicle screw, the screw positions were classified using the Gertzbein and Robbins criteria. This study was partially supported in kind by Mazor Robotics and Medtronic Inc. which provided the robot system.

Results: In 158 screws of the Rom-PLIF group, 9 inserted screws were categorized as grade B, breaching the pedicle by < 2 mm and one screw was grade C. In the Cop-PLIF group, 13 screws and 1 screw was grade B and C violation, respectively, in a total of 172 screws. None of the 74 screws in the Rom-PLIF group violated the proximal facet joint, while 13 of 82 in the Cop-PLIF group violated the proximal facet joint (P < 0.001). The average distance of the screws from the facets was 5.2±2.1 mm vs. 2.7±1.6 mm in the Rom-PLIF and Cop-PLIF, respectively (p < 0.001). Total operating time, time to ambulation and the length of hospital stay were similar between the two cohorts.

Conclusions: The current study demonstrates that robotic-assisted pedicle screw insertion in MIS can ensure accuracy, greater patient safety, and potential advantage about decrease of stress at adjacent segment.