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.