PMC8720452_01
Preoperative magnetic resonance imaging lumbar spine, sagittal T1 with contrast sequence shows an enhancing lesion throughout the body of S1 with invasion ventral to the vertebral body and dorsal into the spinal canal.
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F1
T12, L2, and L3, and a large enhancing lesion of the S1 body with epidural extension causing central canal stenosis and compression of both descending S1 nerve roots [Figure 1].
Preoperative sagittal and axial cuts of the computed tomography lumbar spine without contrast demonstrate a lytic lesion throughout the body of S1.
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F2
There was also a lytic lucency involving the left iliac wing [Figure 2].
Sagittal and axial T2-weighted images of the magnetic resonance imaging lumbar spine that was completed after the first surgery demonstrates L5 anterior subluxation over S1 with severe stenosis.
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F3
The following day, the patient had urinary retention and she emergently underwent a L5 to S2 laminectomy for decompression of stenosis; additionally, an open sacral tumor biopsy was performed. The patient was able to void on postoperative day 1; however, within a few days, she developed increasing pain in her back, buttocks, and down the back of both legs. The follow-up MRI showed progression of the tumor at S1, increased anterior subluxation of L5 over S1, and recurrent central canal stenosis [Figure 3].
Intraoperative fluoroscopy images are shown in photos a, b, and c. Pedicle instrumentation is seen at L4 and L5, and S2-alar-iliac screws caudally. A chest tube is positioned between the inferior endplate of L5 and superior endplate of S2. Progressive cement injection into holes in the chest tube can be seen in a, b, and c, respectively, until the implant was filled and there was appropriate contact at both endplates. In d, a photo of the operative field demonstrates the three-rod construct, as well as the plastic tubing through which cement was injected.
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F4
The cement filled the strut graft until appropriate contact at both endplates was achieved [Figure 4]. Three 5.5 mm rods were placed : the third rod was used to provide extra stability to the construct [Figure 4].
Anterior-posterior (a) and lateral (b) X-rays at the end of the operation demonstrate the instrumentation at L4, L5, and S2-alar-iliac fixation points. A midline slice of an intraoperative computed tomography scan (c) demonstrates the cement interbody in good position.
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F5
A final intraoperative CT scan showed all hardware to be in satisfactory position [Figure 5].