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A New Surgical Technique (Modified Osaka Technique) of Sacral Resection by Posterior-Only Approach: Description and Preliminary Results

Study Design. Operative technique. Objective. To report a new technique for sacral resection, with short-term preliminary results. Summary of Background Data. Although various reports analyzed en bloc excision of sacral tumors, there are still technical problems to improve protection of nerve roots, preserve surrounding structures, and reduce intraoperative bleeding, while maintaining the oncological result. Methods. Thirteen patients were resected for their sacrococcygeal tumor by following the described technique. Two patients had undergone previous surgery elsewhere. The sacrum was exposed by a posterior midline incision and complete soft-tissue dissection. Lateral osteotomies were performed through the sacral foramina using a threadwire saw (devised by Tomita and Kawahara) and Kerrison rongeurs, to avoid damage to the sacral roots. After proximal osteotomy, the sacrum was laterally elevated and mobilized to allow dissection of presacral structures. Mean surgical time was 5.5 hours (range; 1.5–8). Mean blood loss was 2961 mL (range; 1000–8000 mL). Results. Level of resection was proximal in 9 patients and at S3 or below in 4. Margins were wide in 10 patients, marginal in 1, and intralesional in 2. At a mean follow-up of 35.5 months, 9 patients were disease free, while the tumor recurred locally in 4 cases. Complications requiring surgery were seen in 1 case. Conclusion. The reported technique allows wide margins with preservation of roots, and reduction in blood loss and operative time. Indications for posterior-only approach can be extended to resection proximal to S3, when there is minimal pelvic invasion and none or partial involvement of sacroiliac joints. However, the long-term benefits of this technique need to be evaluated.