Use of Expandable Cages in Metastasis to the Spine

Abstract

Introduction: Expandable cages have been utilized as an option for immediate spinal stabilization after vertebrectomy. However, long-term follow-up in the oncology population has not been studied, and results remain unclear. This single-institution series of patients represents our success in utilizing expandable cages. Methods: A retrospective chart review for patients with spinal metastasis treated with expandable cages between 2001 and 2006 was performed with IRB approval. Data regarding date of anterior and posterior surgery, immediate postoperative neurological status versus preoperative status, revision, equipment status, pseudoarthrosis, time to ambulation, and mortality were gathered and analyzed. Results: Twenty-four patients with metastatic cancer to the spine were studied. Cages were placed from T5-L5, 21 of which were single level. Of the 24 patients, 5 (21%) were neurologically intact pre-operatively and postoperatively. 13 of the 24 (54%) improved postoperatively. The remaining six (25%) illustrated no change in neurologic status. No patients deteriorated. At two years’ follow-up, overall patient survival was 79%. Average time to ambulation for patients followed was 11.5 days. No revisions were done for hardware failure, while one revision was performed for tumor progression. Conclusions: Expandable cages appear to be a valid treatment option for the immediate stabilization of the spine following corpectomy from spinal metastasis. Results indicate that fast recovery, reasonable long-term mortality, and immediate stabilization are achievable with this modality. Consequently, expandable cages should be considered as a valid option in the treatment for stabilization following corpectomy in metastasis to the spine. Introduction The spinal column is a frequent site of metastatic disease, particularly from lung, prostate, breast, kidney as the primary sources, whereas primary spinal column tumors comprise a minority of spinal pathology (<2%) 4. Although patients may present in a variety of conditions, pathologic fractures or increased axial spinal pain are frequent issues. Surgical treatment for this disease includes decompression of the neural elements, alleviation of painful symptoms, resolution of mechanical instabilization, and resection of the oncologic burden 2. Surgical treatment options for patients with progressive neurologic deterioration include anterior, posterior or combined decompression with subsequent spinal reconstructions. Expandable cages have recently been utilized as a treatment option for spinal reconstruction after vertebrectomy, particularly in the trauma population1. With increased familiarity of these devices, cages are now being utilized after corpectomy from tumor metastasis, but data regarding this treatment option is lacking 2-3. Vertebral body replacement with expandable cages may provide several potential theoretical advantages such as permitting optimal anatomic placement in addition to concurrent correction of spinal deformity. This manuscript consists of a retrospective review of clinical data from expandable cages after corpectomy in spinal metastatic disease. The hypothesis was these devices would be well tolerated and thus a treatment option in this difficult patient population. Clinical Materials and Methods Between June 2001 and November 2006, twenty-four consecutive patients were retrospectively identified through a chart review that underwent expandable cage reconstruction for metastatic disease with pathologic fractures. Patient research protocol was approved through an institutional IRB. Inclusion criteria included: age greater than 18 years of age, corpectomy between T4 and L5, pathology confirmed metastatic disease. Data points included in the analysis were: age, level of metastasis, primary tumor histology, functional outcome, time to ambulation, need for re-operation, and other perioperative complications. Neurologic examination was performed utilizing the ASIA grading system with motor graded on a six-point scale (0-5) and sensation on a three-point scale (0,1,2) for both pin-prick and touch sensation. Postoperative imaging was taken in all cases to evaluate structural stabilization and Shiveindra Jeyamohan, BS1, Alexander Vaccaro, MD, PhD 2, James S Harrop, MD 3 1Jefferson Medical College, Thomas Jefferson University, Philadelphia, PA 2 Rothman Institute, Philadelphia, PA 3 Department of Neurological Surgery, Thomas Jefferson University, Philadelphia, PA