Validation of Novel Pedicle Screw Scoring System: The HEY Score

Background: There has been no means to assess the quality of insertion of pedicle screws. In this article we validate a novel pedicle screw scoring system. This allows the accuracy of each screw to be measured, which helps trainees develop their skills, allows surgeons to prove their competency, and provides a valuable method for assessing and comparing new technology.

Objective: We proposed that the lower the HEY score the less likely that screw would need revision or be associated with an operative complication.

Design/Methods: In 2-year period, 110 patients had 410 pedicle screws inserted to C7-S1. Patient pathologies were degenerative disease, trauma, and tumor.

Results: Total of 72 pedicle screws were inserted percutaneously (all for trauma patients). 338 screws were inserted via open technique (degenerative, trauma, and tumor patients). In general, 73.6% of screws achieved an Angle (A) score of 1 or 2, 93.7% of screws achieved Width (W) score of 1 or 2, and 87.1% of screws achieved Length (L) score of 1 or 2. The average HEY score (AWL) for all the screws over a 2-year period was 4.29. The average HEY score across the pathologies are 4.74 (degenerative), 4.28 (trauma), 3.74 (tumor). The respective breech rates are 0.39, 0.26, and 0.28 with the majority of the breeches being along the lateral margin of the pedicle. When comparing just traumatic pathologies the open technique achieved a score of 4.59 while percutaneous technique scored 3.99. Their respective breeching rates are 0.26 and 0.23 and this corroborated the previous findings that complication rates was higher in open technique with 16% as against 5% in percutaneous technique.¹ Most screws that breeched had HEY score of >5 in both techniques.

Conclusion: The HEY scoring system provides an important tool for assessing pedicle screw placement. We recommend this novel scoring system for assessment of training, proving one’s competency, and assessing new technologies.