Modified Approach to En Bloc Spondylectomy for Spinal Tumors Protects Great Vessels
Key findings
- Mass General surgeons have developed a modified approach to two-stage total en bloc spondylectomy (TES) that involves passing a threadwire saw between the vertebral body and the thecal sac
- In a series of 33 patients, there were no intraoperative injuries to the spinal cord or great vessels
- Oncologic and functional outcomes in that series were excellent
Compared with piecemeal resection of primary spinal tumors, total en bloc spondylectomy (TES) improves survival and local control. However, damage to vessels anterior to the vertebral column is a common problem, particularly in single-stage posterior approaches, because of the lack of visualization of anterior structures.
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Orthopaedic Spine Surgeon Frank X. Pedlow, MD, Orthopaedic Spine Center Chief Joseph H. Schwab, MD, and colleagues have developed a modified approach to two-stage TES that may reduce the risk of damage to neurovascular structures. In The Journal of Bone and Joint Surgery they detail their technique in which they pass a threadwire saw between the vertebral body and the thecal sac.
The authors also report on all 33 adults who underwent the modified procedure at Mass General between 2010 and 2016. Tumor histology was chordoma in 21 patients, chondrosarcoma in nine, metastatic leiomyosarcoma in one, metastatic mixed germ cell tumor in one and solitary fibrous tumor in one. There were 20 lumbar tumors, 12 thoracic tumors and one spanning the thoracolumbar junction. In 16 patients (48%) the tumor involved only one vertebral level.
Seventeen patients (52%) experienced perioperative complications, including one patient who died. That patient had an L3 to L5 chordoma abutting the great vessels and was unable to tolerate ligation of the inferior vena cava. Infection and deep vein thrombosis were the complications most commonly observed within 90 days after discharge.
Notably, there were no intraoperative injuries to the spinal cord or great vessels. In one patient, the passage of the saw created a dural tear.
Eight patients (25%) required reoperation for instrumentation failure, with a median time to failure of 39 weeks. That percentage and the complication rate in the study are in line with other reports of TES.
As in other studies of TES, the surgeons achieved superior oncologic outcomes: a high negative margin rate (94%) and low tumor recurrence rate (6%). The two patients with positive surgical margins had tumor extension into the epidural space, with a positive margin on the anterior aspect of the dura. Two patients (6%) developed new metastases.
After at least six months of follow-up, all patients had preserved motor function (with mild weakness in seven patients), and 94% remained ambulatory with the ability to provide self-care.
The authors advise that ideal candidates for their modified procedure are those with nonmetastatic primary spinal tumors for whom there are no effective adjuvants, who are medically well enough to undergo the surgery and who are expected to be rendered disease-free. Occasionally, they operate on patients with solitary metastasis to the spine who are well enough to tolerate the procedure.
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