The Gertzbein and Robbins classification assesses the position of transpedicular screws.
Transpedicular screw position is graded from A to E based on the extent by which the screw breaches the cortex of the pedicle 1-3:
- A: fully intrapedicular position without breach of the pedicle cortex
- B: exceeding the pedicle cortex <2 mm
- C: exceeding the pedicle cortex 2-4 mm
- D: exceeding the pedicle cortex 4-6 mm
- E: exceeding the pedicle cortex >6 mm or is outside of the pedicle
Grade A and B can be a considered satisfactory operation result 3. In grade C to E, neurological symptoms may occur and can be evaluated as an unsatisfactory surgical result 1,3.
- 1. Gertzbein SD, Robbins SE. Accuracy of pedicular screw placement in vivo. (1990) Spine. 15 (1): 11-4. doi:10.1097/00007632-199001000-00004 - Pubmed
- 2. Yong Fan, Jin Peng Du, Ji Jun Liu, Jia Nan Zhang, Shi Chang Liu, Ding Jun Hao. Radiological and clinical differences among three assisted technologies in pedicle screw fixation of adult degenerative scoliosis. Scientific Reports. 8 (1): 1. doi:10.1038/s41598-017-19054-7
- 3. Zhang JN, Fan Y, Hao DJ. Risk factors for robot-assisted spinal pedicle screw malposition. (2019) Scientific reports. 9 (1): 3025. doi:10.1038/s41598-019-40057-z - Pubmed