Decompression and instrumentation without fusion for spinal metastases: Loosening rate and consequences

Abstract

Background/PurposeFor patients with spinal metastases, decompression surgery was usually followed by instrumentation without fusion. Over time, mechanical stress would lead to loosening of implants. Yet, there is a lack of studies concerning the loosening rate, or the impact on patients when the implants are loosened. We aim at finding the postoperative loosening rate of implant, postoperative survivorship of patients, as well as their correlation with the mode of instrumentation. MethodsA retrospective study including patients with metastatic spinal cord compression, who received decompression and instrumentation without fusion in a local hospital in Hong Kong from 2007 to 2014 was carried out. Patients with primary spinal tumour or prior spinal fusion were excluded. Demographics, tumour characteristics, mode of instrumentation, loosening rate of implants, as well as survivorship of patients were retrieved. Radiographs at 1 year postoperation were counter-examined by 2 Orthopaedic specialists on the Electronic Patient Record System. ResultsTotal of 65 operations were retrieved. The age ranged from 27 to 84 years old. The most frequent primary source of malignancy was lung (26.5%), followed by breast (24.62%). Thoracic level (60%) was the most frequent site of spinal metastases. The survivorship at 1 year postoperation was 61.54%. The overall loosening rate of implants was 44.44%, with the Luque rods and sublaminar wire system being the most (70%). None of the cases required revision or removal of implants at 1 year postoperation. ConclusionThe loosening rate of implants was high, and it is expected to grow even higher as oncological patients continue to improve in their survivorship with the medical advances such as target therapy. Yet there is still no definite evidence on how the implant loosening would affect patients' quality of life and clinical performance.