Impact of Pedicle Screw Accuracy on Clinical Outcomes After 1 or 2 Level MI-TLIF

Introduction: When creating minimally invasive spine fusion constructs, accurate pedicle screw fixation is essential for biomechanical strength and avoiding complications arising from delicate surrounding structures. As research continues to analyze how to improve accuracy, long term patient outcomes based on screw accuracy remain understudied. The objective is to analyze the long-term patient outcomes based on screw accuracy.

Methods: This is a retrospective cohort study of patients undergoing 1 or 2 level minimally invasive transforaminal lumbar interbody fusion queried from a prospectively maintained multi-surgeon registry. Patient screws were assessed for accuracy and graded as “poor,” “acceptable,” or “good.” Patient demographics and outcomes including complications, patient reported outcome measures, return to activities, and fusion rates were compared between the cohorts.

Results: A total of 665 screws in 153 patients were evaluated and included in the final analysis. Of these, 20 (13.1%) patients had poor screws, 63 (41.2%) patients had acceptable screws, and 70 (40.7%) patients had good screws. All groups showed similar and significant improvements in all patient reported outcome measures though the poor screw group did experience delayed improvement in physical function. A majority of patients in all groups returned to working, driving and discontinued narcotics at similar rates. However, the poor screw group displayed significantly slower return to activities. There were no significant differences in intraoperative or postoperative complications though the poor screw group did experience significantly lower fusion rates.

Conclusion : Patients with poorly accurate pedicle screws experienced delayed return to activities and decreased fusion rates with similar long term patient reported outcome measures. Surgeons should continue to focus on placing accurate pedicle screws and research should continue to analyze ways to ensure accurate screws.