Posterior placement of an expandable cage for lumbar vertebral body replacement in oncologic surgery by posterior simple approach: technical note.

STUDY
DESIGN: Technical note.
OBJECTIVE: To illustrate that posterior placement of expandable cages could be made without any different devices that the ones ordinarily for the procedure. An example case is described. Decompression techniques for vertebral body destruction by tumors and invasion of the spinal canal could need a second surgery for the resection of the tumor and stabilization of the anterior column, which could add morbidity for the patient. The possibility to perform a posterior decompression and anterior reconstruction at the same surgical approach represents an attractive option. SUMMARY OF BACKGROUND DATA: Reconstruction of the anterior column from a posterior approach could be easier for the patient and for the surgeon with this technique.
METHODS: A 17-year-old woman with a benign fibrous histiocytoma in L5 with severe bone destruction, anterior and posterior underwent posterior decompression, vertebral body replacement at the same approach with an expandable cage and L4 S1 pedicle screw fixation in a single stage surgery. This technique consist the resection of the tumor was performed under microscopic view and the vertebral body defect in L5 was resized with a high speed drill to allow the placement of the cage. Over the shoulder of the L5 root and with a gentle traction, the expandable cage was placed in situ with the help of 4 silk threads attached to the heads of the cage, passed ventral and lateral to the dural sac, and roots to facilitate its manipulation and rotation similarly to the Hunt-Shen-Arlet technique. (Hunt T, Shen FH, Arlet V. Expandable cage placement via a posterolateral approach in lumbar spine reconstructions. Technical note. J Neurosurg Spine 2006;5:271-4.) Once the expandable cage is in situ, the headpieces of the parallel distractor are placed over the cage, the upper one over the shoulder of the L5 root under gentle traction on the dural sac, and the lower on over the shoulder of the S1 root under gentle traction too. The distractor was used to rotate the cage at its final position and distracted in situ; the current system instruments provided by the manufacturer were used during the procedure. Then apedicular screw fixation was performed between L4 and S1, and fusion was completed with synthetic bone graft substitute (beta-tricalcium phosphate).
RESULTS: Using a modification of the Hunt-Shen-Arlet technique, without the use of a special distraction devices, the expandable cage was successfully implanted and expanded in situ. The clinical result was excellent.
CONCLUSION: A surgical technique for the replacement of vertebral body by posterior approach is presented. This technique could be used in surgery of vertebral body tumors of the lumbar spine, in a single surgical approach.