Surgical classification of different types of en bloc resection for primary malignant sacral tumors

The purpose of the study was to develop a surgical classification system for primary malignant sacral tumors.

The sacrum is divided into three regions 1, 2 and 3 by the S1-S2 and S2-S3 junctions. En bloc resections were classified into five types: type I involves regions 1, or 1 and 2, or regions 1, 2 and 3, type II involves regions 2 and 3, and type III involves only region 3. Type IV includes sagittal hemisacrectomy and resection of a portion of the adjacent ilium. Type V includes the sacrum and the fifth lumbar vertebra. 117 patient cases (68 females and 49 males) were reviewed.

There were two perioperative deaths. Of the 35 patients who should have undergone type I resection, local recurrence (LR) occurred in four of the 14 patients who underwent type I resection with free margins without tumor rupture. The other 21 patients underwent piecemeal resection, and LR occurred in 15 (P = 0.013). 35 patients underwent type II resection. Free margin without tumor rupture was accomplished in 26 and LR occurred in 6. Tumor rupture (TR) occurred in the other 9 and LR occurred in seven (Yates' P = 0.012). All 33 patients underwent type III resection with free margins without tumor rupture. LR occurred in five. 11 patients had type IV resection. Free margin without tumor rupture was accomplished in seven and LR occurred in three. TR occurred in the other four, and LR occurred in two (Yates' P = 0.689). One patient underwent type V resection with free margin without tumor rupture and LR occurred. Postoperatively, less than 1/3 needed long-term urethral catheterization. No patients received colostomy for postoperative fecal incontinence. All the patients were able to ambulate.

Our classification system and the corresponding surgical approaches are helpful in dealing with primary malignant sacral tumors. Better oncologic results could be expected if free margin without tumor rupture was accomplished.