The Outcome of Pedicle Screw Instrumentation Removal for Chronic Low Back Pain

Abstract

Introduction There have been a limited number of small case series reporting improvement in patients' function and pain scores following removal of pedicle screw metalwork for nontraumatic lumbar fusion surgery. The investigators' aim was to determine the degree of satisfaction from a patient cohort; and improvement in pain status after removal of pedicle screw instrumentation and factors that may influence the outcome. Methods Patients who had removal of pedicle screw instrumentation for posterolateral lumbar fusion in the preceding 2 years were identified from the database of a single spinal surgeon's case series. All patients completed pre- and postoperative Oswestry Low Back Pain Disability Questionnaire (ODI). Patient inclusion criteria were persistent axial low back pain imaging confirmed solid fusion, nonradicular symptoms and no other cause found for pain, for example, infection. Exclusion criteria included exchange of metal work, revision fusion, or other additional therapeutic procedures. Following removal of metal work via previous incisions, all patients had debridement of fibromuscular tissue and adhesiolysis, thorough saline lavage, and local bone grafting to the site of metal removal. Results A total of 21 patients were identified from the database with a mean follow-up of 14 months (range, 3–24 months). There were two postoperative hematomas requiring aspiration but no additional complications such infections, reoperations, or deterioration of neurological deficits. The former two patients did not record improvement in VAS and both were neutral in satisfaction. Treatment success as assessed from the ODI analysis was rated as excellent in 6 of 21, good in 7 of 21, fair in 5 of 21, and poor in 2 of 21. Reduced class II opioids, benzodiazepines, or neuromodulator use was reduced in 7of 21, no different in 11of 21, and increased in 3 of 21. The proportion of patients with an improvement in VAS was 13 of 21 (62%) with an improvement of at least 2 or more being (43%) 9 of 21 of patients surveyed. The visual analog scores were the only component of the ODI able to be assessed for all of the patients with mean scores of 5.9 preoperatively to 4.2 postoperatively ( p = 0.04). The proportion of patients with an improvement in VAS was 13 of 21 (62%) with an improvement of 2 or more being 9 of 21 (43%) of patients surveyed. Patients who did not receive analgesic benefit and/or had lower satisfaction from the removal of instrumentation procedure tended to be male, compensable, had experienced more years of symptoms, shorter times to metal wear removal, and an increased prevalence of preoperative class II opioid requirements. There was, however, no trend to a difference with regards to number or location of levels fused, number of procedures, presence of pseudoarthrosis or broken/loose metal wear and method of preoperative fusion confirmation. Of the 21 patients, 14 (67%) patients indicated that they would undergo the same treatment again given their experience and outcome. Conclusion In our series, removal of pedicle screw implants in individuals with ongoing low back pain following solid fusion lead to good or excellent results in two-third of patients and did not lead to any adverse effects and/or complications.