Novel Applications of Robot-assisted Navigation in the Treatment of Lumbar Adjacent Segment Disease: A Case Series

Introduction: Symptomatic adjacent segment disease (ASD) commonly develops following a primary lumbar fusion and often requires reoperation. Traditionally, reoperation necessitates exposure and/or revision of primary instrumentation which is associated with an increase in operative time, blood loss, and complications. Here, we report on the use of minimally invasive robot-assisted navigation (RAN) to accomplish pedicle screw instrumentation that avoids revision and exposure of primary hardware in the setting of ASD reoperation.

Methods: A retrospective review of five patients treated for lumbar ASD using RAN was conducted. All patients underwent minimally invasive posterior decompression and interbody fusion using a microscopic tubular approach followed by robot-navigated posterior pedicle screw instrumentation. Data on demographics, BMI, surgical indications, pre-operative planning data, operative outcomes, and short-term clinical outcomes were collected. Descriptive statistics were used to analyze the data.

Results: The mean age was 71.2 years, mean operative time was 117.6 minutes, mean operative time per screw was 27.2 minutes, mean estimated blood loss was 30mL, mean BMI was 36.64, and mean length of stay was 1.2 days. A total of 22 screws were instrumented using RAN. Of these, eight screws were placed in previously instrumented vertebral levels without removing prior hardware. Four of these screws were placed in a cortical bone trajectory and two in a transpedicular trajectory. Patients were treated for both single- and multi-level ASD. There were no complications.

Conclusion : The authors demonstrate a novel application of RAN for the treatment of ASD which obviates exposure, revision, or removal of prior hardware. To our knowledge, this is the first report of multilevel ASD treatment that obviates revision of the primary hardware. This method provides a minimally invasive approach to ASD reoperations which avoids revision, while demonstrating capacity to maintain safety, efficiency, and optimal perioperative outcomes. We will follow these patients long-term to ensure clinical and biomechanical durability.