En bloc resection of huge primary tumors with epidural involvement in the mobile spine using the "rotation-reversion" technique: Feasibility, safety, and clinical outcome of 11 cases

Abstract

Background: En bloc resection of spinal tumors provides better local control and survival outcomes than intralesional resection. Safe margins during en bloc resection of primary spinal tumors with epidural involvement are required for improved outcomes. The present study describes a "rotation-reversion" technique that has been used for en bloc resection of huge primary tumors in the mobile spine with epidural involvement and reported the clinical outcomes in these patients.

Methods: All patients with primary spinal tumors who were treated with the rotation-reversion technique at our institution between 2015 and 2021 were evaluated retrospectively. Of the patients identified, those with both huge extraosseous soft-tissue masses and epidural involvement were selected for a case review. Clinical and radiological characteristics, pathologic findings, operative procedures, complications, and oncological and functional outcomes of these patients were reviewed.

Results: Of the 86 patients identified with primary spinal tumors who underwent en bloc resection using the rotation-reversion technique between 2015 and 2021, 11 had huge extraosseous soft-tissue masses with epidural involvement in the mobile spine. The average maximum size of these 11 tumors was 8.1 × 7.5 × 9.7 cm. Median follow-up time was 28.1 months, mean operation time was 849.1 min (range 465-1,340 min), and mean blood loss was 6,972.7 ml (range 2,500-17,700 ml), with 10 (91%) of the 11 patients experiencing perioperative complications. The negative margin rate was 91%, with only one patient (9%) experiencing local recurrence. Ten patients were able to walk normally or with a crutch at the last follow-up, whereas one was completely paralyzed preoperatively.

Conclusion: The rotation-reversion technique is an effective procedure for the en bloc resection of huge primary spinal tumors, with the extension of invasion in selected patients including not only the vertebral body but also the pedicle and part of the posterior arch.

Keywords: en bloc resection; epidural involvement; huge mass; rotation-reversion technique; safe margin; spinal tumor.

Figure 1

Illustration of en bloc resection using the rotation–reversion technique through a single posterior approach in the thoracic spine. A safe window was opened at the posterior arch, and nerve roots on the unaffected side were sectioned. The dura was separated from the lesion, and the nerve roots on the side covered by the tumor were sectioned under direct visualization by the rotation technique. The great vessels and surrounding structures at the ventral side of the tumor-invaded vertebrae were bluntly dissected under direct visualization using the reversion technique from the posterior approach. Reversal of the entire mass was continued until it was completely removed posteriorly.

Figure 2

Illustration of en bloc resection using the rotation–reversion technique using a combined anterior and posterior approach in the lumbar spine. The retroperitoneal space was entered through a bilateral anterior pararectus approach, and the aorta and inferior vena cava were separated from the diseased vertebral body. The left hemivertebral body and pedicle of the diseased vertebrae were piecemeal removed as a safe window to enter the spinal canal. The mass in the bilateral paravertebral soft tissue that was not infiltrated by the tumor was separated using a posterior approach. The dura was separated from the mass, and the bilateral never roots of the diseased vertebrae were sectioned under direct visualization by the rotation technique. Finally, the entire mass was removed posteriorly using the reversion technique.

Figure 3

A 46-year-old woman with a malignant neurilemmoma at L3 with a huge mass in the posterior elements (A–C). En bloc resection through a combined anterior and posterior approach was designed based on WBB classification along the margins, as highlighted by white dotted line (sectors 7–2, D, WBB) (D). The dura was separated from the mass, and bilateral nerve roots of L3 were sectioned under direct visualization using the rotation technique (J). Photographs of the gross specimen (E, F) showing that the epidural extension of the tumor was fully contained by the ligamentum flavum. Radiographs of the specimen (G–I) showing the margins of en bloc resection. WBB, Weinstein–Boriani–Biagini.

Figure 4

A 61-year-old man with a malignant neurilemmoma at L4–5. Preoperative MR images (A–C) show the tumor invading the left side of the L4 and L5 vertebrae sectors 1–6, (D), WBB with a huge mass in the posterior elements (from L2 to S3). The patient underwent a two-stage surgery, consisting of anterior release followed by posterior sagittal en bloc resection with instrumentation. A photo of the gross specimen (E) and postoperative CT scan imaging (F–H) showing the margins on sagittal scans of en bloc resection. Postoperative CT scan reconstruction shows structural reconstruction with instrumentation after sagittal resection (D). WBB, Weinstein–Boriani–Biagini.

Figure 5

A 40-year-old man with osteosarcoma at T11-L2. This patient experienced a local tumor recurrence after two rounds of intralesional excision surgeries combined with radiotherapy in another hospital. MR images (A–C) show tumor recurrence along the right side of T11 to L2 paravertebral with epidural involvement (sectors 4–1, D, WBB). Based on the WBB classification, a four-level (T11-L2) en bloc spondylectomy was performed using the rotation–reversion technique after three courses of chemotherapy. However, due to intracanal tumor contamination caused by the initial operations, the margin along the dura was considered positive (D). Radiographs of the specimen (E–G) and postoperative CT scans showing structural reconstruction with instrumentation after tumor resection (H). WBB, Weinstein–Boriani–Biagini.

Figure 6

A 70-year-old man with chondrosarcoma at C7–T1. The patient had undergone a piecemeal resection of a tumor in the paravertebral region of the cervicothoracic junction at another hospital. Ten months later, the patient experienced numbness in his upper left arm. MR images (A–C) show tumor recurrence along the left side of C7 to T1 paravertebral CT scans (D, E), and CT angiography (F) shows that the left vertebral artery was invaded by the tumor (sectors 1–5, D, F, WBB). Based on the WBB classification of the tumor, sagittal en bloc resection was performed using the rotation–reversion technique with a combined approach. The left vertebral artery was cut off outside the tumor and anastomosed with the left common carotid artery (K). Postoperative CT angiography showing fluent blood flow in the left vertebral artery (L). Postoperative CT scanning (G–I) and a photograph of the gross specimen (J) showing the margins of sagittal en bloc resection. WBB, Weinstein–Boriani–Biagini.