Background Although instrumentation (hardware, HW) has improved rates of spinal arthrodesis, it can sometimes cause irritation, requiring its removal (HWR). Very little has been demonstrated about the efficacy of HWR in relieving pain and improving function, especially in patients without pseudarthrosis (PA) or other “obvious pain generators.” This study quantifies and reports the 1) demographics and operative indications of patients undergoing HWR 2) intraoperative findings during HWR surgery 3) outcomes following HWR for patients both with and without PA or other “obvious pain generators” and 4) predictors of HWR outcomes.
Methods Retrospective review of 42 patients undergoing HWR at one university center from 2001–04. Operative procedures included HWR, re-fusion of PA (when present), and a preoperative diagnostic HW Injection (anesthetic) for 50% of patients. Patient outcomes were assessed using clinic/operative notes, radiographs, and questionnaires assessing pain, functional improvement, patient satisfaction, and medication usage. We used Odom’s criteria to assign an overall outcome score for each patient.
Results Intraoperatively, 5 Patients had confirmed PA, 3 bent/broken HW, and 3 loose HW. On average, for patients without PA or obvious pain generators, HWR provided significant pain relief (47.3%) and functional improvement while decreasing usage of pain medication. Odom scores were high for all patients. Pain relief from HWR and from HW injection was highly correlated (r=0.78). Younger patients, those with more fused segment, and those with more time without pain following initial arthrodesis had significantly increased pain relief from HWR. Female patients had better overall outcomes (Odom scores).
Conclusions Our findings demonstrate overall pain and functional improvement following HWR for patients without PA or obvious pain generators, and identify variables that predict successful pain relief and good outcomes following HWR. We also show for the first time that HW injection is a highly reliable diagnostic tool for predicting pain relief from HWR.