Table 2 Details of the two foraminoplasty procedure
| Â | Target region | The inclination of the trephine | Removed section | The depth of foraminoplasty | |
|---|---|---|---|---|---|
In lateral view | In AP view | ||||
The first foraminoplasty | Retrodiscal space (Zone 1) | From the tip of superior articular process (SAP) to the posterior rim of the upper endplate of distal vertebral | From the tip of SAP to midpoint of upper endplate of distal vertebral body | Upper-medial-ventral part of facet joint which comprise tip and upper-ventral part of SAP, a part of inferior articular process (IAP) and a small ventral part of laminar. | Limited to 10–12 mm controlled by the special designed trephine |
The second foraminoplasty | Upper bony lateral recess (zone 2) | From the tip of SAP to the cross-point of middle pedicular line and the posterior surface of vertebral body | From the tip of SAP to midpoint of middle pedicular line | Lower medial-ventral part of SAP | Limited to 12–14 mm controlled by the special designed trephine |