Correlation of Early Outcomes and Intradiscal Interleukin-6 Expression in Lumbar Fusion Patients.

OBJECTIVE: To determine if there is correlation between intradiscal levels of interleukin-6 (IL-6) and early outcome measures in patients undergoing lumbar fusion for painful disc degeneration. METHODS: Intervertebral disc tissue was separated into annulus fibrosus/nucleus pulposus and cultured separately in vitro in serum-free medium (Opti-MEM). Conditioned media was collected after 48 hours. The concentration of IL-6 was quantified using enzyme-linked immunosorbent assay. Pearson correlation coefficients quantified relationships between IL-6 levels and pre- and postoperative visual analogue scale (VAS) back pain and Oswestry Disability Index (ODI), as well as change in VAS/ODI. RESULTS: Sixteen discs were harvested from 9 patients undergoing anterior lumbar interbody fusion (mean age, 47.4 years; range, 21-70 years). Mean preoperative and 6-month postoperative VAS were 8.1 and 3.7, respectively. Mean preoperative and postoperative ODI were 56.2 and 25.6, respectively. There were significant positive correlations between IL-6 expression and postoperative VAS (ρ = 0.38, p = 0.048) and ODI (ρ = 0.44, p = 0.02). No significant correlations were found between intradiscal IL-6 expression and preoperative VAS (ρ = -0.12, p = 0.54). Trends were seen associating IL-6 expression and change in VAS/ODI (ρ = -0.35 p = 0.067; ρ = -0.34, p = 0.08, respectively). A trend associated IL-6 and preoperative ODI (ρ = 0.36, p = 0.063). CONCLUSION: The direct association between IL-6 expression and VAS/ODI suggests patients with elevated intradiscal cytokine expression may have worse early outcomes than those with lower expression of IL-6 after surgery for symptomatic disc degeneration

Proximal Junctional Spondylodiscitis Following Adult Spinal Deformity Surgery: Case Series and Review of the Literature.

BackgroundProximal junctional failure (PJF) following multilevel thoracolumbar instrumented to the pelvis for adult spinal deformity (ASD) is relatively uncommon but considerably disabling. While the leading etiology is mechanical, other rarer etiologies can play a role in its development. The purpose of this study was to present a case series of ASD patients who experienced PJF secondary to proximal junctional spondylodiscitis (PJS) after long-segment thoracolumbar posterior instrumented fusions.MethodsAdult patients who underwent posterior instrumented fusions at a single academic center between 2017 and 2020 and subsequently developed PJS were retrospectively reviewed. Patient demographics, operative details, clinical presentation, culture data, and management approach were evaluated.ResultsThree patients developed PJS and were included for analysis (mean age 67 years [range, 58-76]; women: 2). Indication for all index operations was symptomatic ASD after failed conservative management. Clinical presentation ranged from mild back pain to severe neurological compromise. Average time to infection and PJF after the index procedure was 11 months (range, 3 months-2 years). All 3 patients were successfully managed with urgent revision surgery including surgical debridement and postoperative antibiotics.ConclusionPJS is a rare yet potentially devastating complication following long-segment posterior thoracolumbar instrumented fusions for ASD. It is critical that surgeons maintain a high index of suspicion of infection when managing PJF given the potential neurological morbidity of PJS.Clinical relevanceThis report highlights a rare but important cause of PJF following ASD surgery. It is critical that one maintains a high index of suspicion of infection when managing PJF.Level of evidence: