Neurosurgery Resident University of South Florida, Department of Neurosurgery and Brain Repair University of South Florida, Department of Neurosurgery Tampa, Florida, United States
Introduction: Thoracolumbar corpectomy is an essential tool for restoration of anterior and middle column support. However, subsidence remains a challenge. This may be mitigated by using wide-footprint endcaps that rest on the peripheral vertebral endplate. We describe a new technique, named the “buttress technique” that further reduces subsidence.
Methods: First, fenestrated pedicle screws above the corpectomy cage are angled caudally such that the tips of the screws are just deep to the surface of the inferior endplate in contact with the corpectomy cage. The pedicle screws below the cage are similarly angled cranially. Second, cement augmentation of the fenestrated screws helps create a more solid endplate and further reduces the chance of subsidence
Disc height was measured as an average between anterior and posterior intervertebral disc height, normalized by the anterior-posterior diameter of the caudal vertebral body superior endplate. Subsidence was classified into four grades: Grade 0, 0-24%; Grade 1, 25-49%; Grade 2, 50-74%, Grade 3, 75-100%.
Results: Twenty-six consecutive patients who underwent thoracolumbar corpectomy with the buttress technique were identified over a 3 year period (Sept 2021-Sept 2024). Twenty one had sufficient radiographic studies available for analysis. Average follow up was 13 months, with range of 1 to 34 months. Fourteen patients underwent single-level corpectomy, three patients underwent two-level, and four underwent three-level. All patients had improved pain, and none had a new neurologic deficit. There was no instance of implant failure. All patients demonstrated grade zero subsidence. Maximum percent change in disc height was 20%, which occurred in a patient undergoing a 2-level corpectomy after 1 month. The average change in disc height was 5.2%.
Conclusion : The buttress technique offers a promising solution to the challenge of subsidence inherent in thoracic and lumbar corpectomies. Further study and follow up are needed to confirm the utility and durability of this technique.
.jpg)
