Surgical strategy for cervical dumbbell tumors based on a three-dimensional classification

Study Design. Forty- two patients with cervical dumbbell tumors were analyzed retrospectively using a new three- dimensional classification. Objectives. To establish optimal surgical strategies, we considered shapes and three- dimensional locations of cervical dumbbell tumors based on diagnostic images and intraoperative findings. Summary of Background Data. Eden's classification for dumbbell tumors of the spine, long considered a " gold standard," no longer is sufficient to determine surgical strategy in view of recent advances in computed tomography and magnetic resonance imaging. Methods. Forty- two cervical dumbbell tumors were characterized according to transverse- section images ( Toyama classification; nine types) and craniocaudal extent of intervertebral and transverse foraminal involvement ( IF and TF staging; three stages each). Results. Type IIIa tumors, involving dura plus an intervertebral foramen, accounted for 50% of cases. A posterior approach was used in 35 patients; 7 others underwent a combined anterior and posterior approach. A posterior approach was used for all type IIa and IIIa tumors, and for some type IIIb ( upper cervical), IV, and VI tumors; a combined posterior and anterior approach was used for type IIb and the remainder of type IV and VI. Reconstruction was performed using spinal instrumentation in 4 patients ( 9.5%). Resection was subtotal in 6 patients ( 14.3%) and total in 36 ( 85.7%). Conclusions. Systematic, imaging- based three- dimensional characterization of shape and location of cervical dumbbell tumors is essential for planning optimal surgery. The classification used here fulfills this need.