Is removal of the internal fixation after successful intervertebral fusion necessary? A case–control study based on patient-reported quality of life

Background Intervertebral fusion and internal fixation are often applied to patients with lumbar spinal disease. Whether to remove the internal fixation after successful fusion remains uncertain, but such a question needs to be explored in light of concerns regarding patients’ quality of life and health insurance. We sought to probe if the removal of internal fixation after successful lumbar intervertebral fusion affects patients’ quality of life. Methods This was a real-world retrospective case–control study. Data of 102 patients who had undergone posterior lumbar fusion with cage and internal fixation to treat lumbar degenerative diseases were extracted from a single center from 2012 to 2020. Fifty-one patients had undergone internal fixation removal surgery, and 51 controls who retained internal fixations were matched according to demographic and medical characteristics. The quality of life of patients based on the Medical Outcomes Study Short Form 36 (SF-36) scale and their self-assessment were surveyed. Results There was no statistical difference in the overall score of the SF-36 questionnaire between the two groups, but the general health (GH) subscore was lower in the case group than in the control group ( P = 0.0284). Among those patients who underwent internal fixation removal, the quality of life was improved after instrument removal as indicated by an increased overall score ( P = 0.0040), physical functioning (PF) ( P = 0.0045), and bodily pain (BP) ( P = 0.0008). Among patients with pre-surgery discomfort, instrument removal generated better outcomes in 25% and poor outcomes in 4.2%. Among patients without pre-surgery discomfort, instrument removal generated better outcomes in 7.4% and poor outcomes in 11.1%. Conclusion Among patients who achieved successful posterior lumbar internal fixation, whether or not to remove the fixation instruments should be evaluated carefully. In patients experiencing discomfort, instrument removal could improve their quality of life, but the benefits and risks should be comprehensively explained to these patients. Instrument removal should not be routinely performed due to its limited or even negative effect in patients who do not report discomfort before surgery.