Malignant Pelvic Tumors Involving the Sacrum: Surgical Approaches and Procedures Based on a New Classification

Objective To introduce a new classification of E nneking type IV pelvic tumors involving the sacrum and a corresponding system of standardized surgical approaches and procedures for resection of such tumors, and to investigate the feasibility and therapeutic effect of the new system. Methods Data on 59 patients treated between F ebruary 2003 and F ebruary 2013 by standardized surgical approaches and procedures were retrospectively reviewed. The study subjects comprised 28 male and 31 female patients with a mean age at diagnosis of 36 years (range, 2–72 years). There are four subtypes in the new classification: (i) subtype IV a, neoplasms invading the ipsilateral sacral wing; (ii) subtype IV b, neoplasms invading the ipsilateral sacral foramina; (iii) subtype IV c, neoplasms invading the contralateral sacral foramina; and (iv) subtype IV d, neoplasms invading the whole of the sacrum. Standardized surgical approaches and procedures were devised for en‐bloc resection for each subtype with adequate margins. Results Adequate margins were achieved in 43/59 patients (72.9%). The mean operation time was 5.0 h and the mean intraoperative blood loss 2157 mL. At the final follow‐up, 27/53 patients (50.9%) who had been followed up were alive and in complete remission. The mean M usculoskeletal T umor S ociety 93 score was 17.4 (58%) of a possible 30 points. The mean functional score for patients who had undergone a pelvic zone II resection was 15.2, compared with 19.0 for those with an intact pelvic zone II . Conclusions The proposed standardized protocols should help orthopaedic surgeons to achieve adequate margins, manage risk, achieve better oncologic and functional outcomes, and minimize perioperative complications when treating massive pelvic tumors involving the sacrum.