【INTRODUCTION】One of the problems for the 5th lumbar spine (L5) is the difficulty to access L5 vertebral body from posterior by the prominence of iliac crest and paravertebral muscles. Therefore, surgical techniques are limited for L5 lesion from posterior through narrow posterior window by the difficulty of getting direct visualization and the angular limitations of handling instruments. The aim of this report is to show the cases with L5 lesion using retrograde erector spinae transposition approach by cutting posterior iliac crest.
【METHODS】Retrograde transposition of erector spinae by cutting posterior iliac crest approach started from midline skin incision. After the exposure of sacrum, posterior iliac crest was cut along with the posterior surface of sacrum. Erector spinae was trans-positioned from caudal maintaining continuation with posterior iliac crest. Anterolateral L5 vertebral wall was released from common iliac vessels and L5 vertebra was removed between L4 and L5 nerve roots after cutting sacrum alar and releasing these nerve roots in the cases of en-block spondylectomy and hemi-verterectomy. Posterior iliac crest was fixed at original position by screws and/or suturing surrounding soft tissues. Cases were shown using this approach.
【RESULTS】 This approach was used for five cases of L5 lesions: two cases of en-block spondylectomy for metastasis of uterine adenocarcinoma and giant cell, two cases of hemi-verterectomy for metastasis of clear cell renal carcinoma and aggressive osteoblastoma, and one case of decompression for spinal canal stenosis secondary to achondroplasia. Severe lumbar pain was occurred in one case with dispositioned posterior iliac crest after suturing with surrounding soft tissues.
【DISCUSSION】
Retrograde erector spinae transposition approach by cutting posterior iliac crest was useful especially for L5 vertebral tumors. This approach enables to get direct visualization of antero-lateral side of L5 vertebral wall, to conduct releasing common iliac artery and vein, and to remove L5 vertebral body from posterior. Stiff fixation was needed for posterior iliac crest because of continuation of elector spinae.