Use of PEEK/Carbon Fiber Instrumentation Improves Postoperative Surveillance and Radiation Planning in a Case of Lumbar Spine Chordoma

Introduction: Chordomas are radioresistant invasive tumors that have a high rate of local recurrence. Proton therapy can safely deliver higher radiation doses sparing delicate surrounding structures. Wide surgical resection is invariably destabilizing and artifacts due to metallic hardware can obscure diagnostic and simulation imaging, and can be associated with inferior outcomes. The use of PEEK/carbon fiber instrumentation in these patients reduces postoperative imaging artifact, improves radiation therapy planning, and provides greater safety and quality of radiotherapy due to less beam scattering.
Here we present a case of a patient with a lumbar spine chordoma who underwent intratumoral debulking and stabilization using PEEK/carbon fiber hardware and subsequent proton beam radiotherapy.

Methods: 50-year-old male presented with left flank pain, radiculopathy and weakness, imaging demonstrated an L3 mass with epidural extension, encasement of the cauda equina and extension into adjacent soft tissues. Biopsy was consistent with chordoma. Due to tumor involvement of the psoas muscle and lumbosacral plexus, an en bloc resection would be highly morbid for this patient. Therefore, he underwent a L3 vertebrectomy, intratumoral debulking and L2-4 arthrodesis with PEEK/carbon fiber pedicle screw fixation, cement augmentation and placement of a cage. He subsequently underwent 74 Gy of proton beam radiotherapy to the residual soft tissue mass, tumor bed and surgically manipulated tissues.

Results: One-year postoperative MRI and PET/CT demonstrate intact hardware, new bone growth across the cage, no evidence of recurrence and good response to treatment. His radiculopathy and weakness have completely resolved and he has not developed any neurological deficits or radiation side effects.

Conclusion : Metallic artifacts from implanted hardware used for spine stabilization in oncologic patients cause decreased delineation confidence, dose calculation accuracy and increased time spent on manually delineating pixels in radiotherapy. This is of paramount importance in radioresistant tumors such a chordomas which require high dose radiation to areas surrounded by vital organs and neural elements. We demonstrate that the use of PEEK/carbon fiber instrumentation is a safe alternative to titanium that provides superior delineation, radiation planning and recurrence surveillance while maintaining construct integrity and spine stability.