Asymptomatic Construct Failure after Metastatic Spine Tumor Surgery: A New Entity or a Continuum with Symptomatic Failure?

• Published in: Asian spine journal Vol. 15; no. 5; pp. 636 - 649
• Main Authors: Kumar, Naresh, Patel, Ravish, Tan, Barry Wei Loong, Tan, Jiong Hao, Pandita, Naveen, Sonawane, Dhiraj, Lopez, Keith Gerard, Wai, Khin Lay, Hey, Hwee Weng Dennis, Kumar, Aravind, Liu, Gabriel
• Format: Journal Article
• Language: English
• Published: Seoul Korean Society of Spine Surgery 01-10-2021; Korean Spine Society; 대한척추외과학회
• Subjects: artificial implants; Asymptomatic; Back surgery; Bone cancer; Bone surgery; Breast; Clinical Study; Demography; Failure; Hematology; implant failure; Liver cancer; Metastases; Metastasis; neoplasm metastasis; Ovaries; Pain; Patients; Prostate; Risk factors; Spinal cancer; spine; surgery; Survival; Thyroid gland; Tumors; 정형외과학
• ISSN: 1976-1902; 1976-7846
• DOI: 10.31616/asj.2020.0167

Study Design: Retrospective cohort study.Purpose: To study the incidence, onset, underlying mechanism, clinical course, and factors leading to asymptomatic construct failure (AsCF) after metastatic spinal tumor surgery (MSTS).Overview of Literature: The reported incidence rates for implant and/or construct failure after MSTS are low (1.9%–16%) and based on clinical presentations and revisions required for symptomatic failures (SFs). AsCF after MSTS has not been reported.Methods: We conducted a retrospective analysis of 288 patients (246 for final analysis) who underwent MSTS between 2005–2015. Data collected were demographics and peri/postoperative clinical and radiological features. Early and late radiological AsCF were defined as presentation before and after 3 months, respectively. We analyzed patients with AsCF for risk factors and survival duration by performing competing risk regression analyses where AsCF was the event of interest, with SF and death as competing events.Results: We observed AsCF in 41/246 patients (16.7%). The mean time to onset of AsCF after MSTS was 2 months (range, 1–9 months). Median survival of patients with AsCF was 20 and 41 months for early and late failures, respectively. Early AsCF accounted for 80.5% of cases, while late AsCF accounted for 19.5%. The commonest radiologically detectable AsCF mechanism was angular deformity (increase in kyphus) in 29 patients. Increasing age (p<0.02) and primary breast (13/41, 31.7%) (p<0.01) tumors were associated with higher AsCF rates. There was a non-significant trend towards AsCF in patients with a spinal instability neoplastic score ≥7, instrumentation across junctional regions, and construct lengths of 6–9 levels. None of the patients with AsCF underwent revision surgery.Conclusions: AsCF after MSTS is a distinct entity. Most patients with early AsCF did not require intervention. Patients who survived and maintained ambulation for longer periods had late failure. Increasing age and tumors with a better prognosis have a higher likelihood of developing AsCF. AsCF is not necessarily an indication for aggressive/urgent intervention.