Superior Facet Joint Violations during Single Level Minimally Invasive Transforaminal Lumbar Interbody Fusion: A Preliminary Retrospective Clinical Study

Figure 1

Shah’s classification. (a) (grade 1): no facet joint violation; (b) (grade 2): unilateral facet joint violation (screw head contacted or invaded facet joint); (c) (grade 3): bilateral facet joint violation (screw head contacted or invaded facet joint).

(a)

(b)

(c)