Alan H Daniels1, J Mason DePasse2, Wesley Durand3, D Kojo Hamilton4, Peter Passias5, Han Jo Kim6, Themistocles Protopsaltis5, Daniel B C Reid2, Virginie LaFage6, Justin S Smith7, Christopher Shaffrey7, Munish Gupta8, Eric Klineberg9, Frank Schwab6, Doug Burton10, Shay Bess5, Christopher Ames11, Robert A Hart12. 1. Department of Orthopaedics, Division of Spine Surgery, Alpert Medical School of Brown University, Providence, Rhode Island, USA. Electronic address: alan_daniels@brown.edu. 2. Department of Orthopaedics, Division of Spine Surgery, Alpert Medical School of Brown University, Providence, Rhode Island, USA. 3. Department of Orthopedics, Alpert Medical School of Brown University, Providence, Rhode Island, USA. 4. Department of Neurosurgery, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA. 5. Department of Orthopedics, NYU Langone Orthopedic Hospital, New York, New York, USA. 6. Department of Orthopedics, Hospital for Special Surgery, New York, New York, USA. 7. Department of Neurosurgery, University of Virginia Health System, Charlottesville, Virginia, USA. 8. Department of Orthopedics, Washington University, St. Louis, Missouri, USA. 9. Department of Orthopedics, University of California-Davis, Sacramento, California, USA. 10. Department of Orthopedics, University of Kansas Hospital, Kansas City, Kansas, USA. 11. Department of Neurosurgery, University of California-San Francisco, California, USA. 12. Department of Orthopedics, Swedish Neuroscience Institute, Seattle, Washington, USA.
Abstract
BACKGROUND: Rod fracture occurs with delayed fusion or pseudarthrosis after adult spinal deformity (ASD) surgery. Rod fracture after apparent radiographic fusion has not been previously investigated. METHODS: Patients with ASD in a multicenter database were assessed for radiographic fusion by a committee of 3 spinal deformity surgeons. Fusions were rated as bilaterally fused (A), unilaterally fused (B), partially fused (C), or not fused (D). Patients with grade A or B fusion and 2-year follow-up were included. Patients with radiographic fusion were evaluated for subsequent rod fracture. Adjusted analyses were conducted with multiple logistic regression, using backwards-variable selection to a threshold of P < 0.2, to assess for associated factors. RESULTS: Of 402 patients with radiographically apparent solid fusion, 9.5% (38) subsequently suffered a broken rod. On multivariate analysis, greater rates of rod fracture were seen among patients of age group 60-69 years (vs. 18-49), body mass index 30-34 and 35+ (vs. <25), stainless-steel rods (vs. titanium), patients with rods ≤5.5 mm (vs. 6.35 mm), and patients with Charlson score 0 (vs. 3+). Of the 38 patients with rod fractures, 18 (47.4%) presented with worsened pain, and 8 (21.1%) required revision at minimum 2-year follow-up. CONCLUSIONS: Rod fracture occurred in 9.5% of patients with apparently solid radiographic fusion after ASD surgery. Advanced age, obesity, small diameter rods (5.5 mm), osteotomy, and lower comorbidity burden were significantly associated with rod fracture. Nearly one-half of these patients noted worsening pain, and 21.1% required revision surgery. Instrumentation failure may occur and may be symptomatic even in the setting of apparent fusion on plain radiographs.
BACKGROUND: Rod fracture occurs with delayed fusion or pseudarthrosis after adult spinal deformity (ASD) surgery. Rod fracture after apparent radiographic fusion has not been previously investigated. METHODS:Patients with ASD in a multicenter database were assessed for radiographic fusion by a committee of 3 spinal deformity surgeons. Fusions were rated as bilaterally fused (A), unilaterally fused (B), partially fused (C), or not fused (D). Patients with grade A or B fusion and 2-year follow-up were included. Patients with radiographic fusion were evaluated for subsequent rod fracture. Adjusted analyses were conducted with multiple logistic regression, using backwards-variable selection to a threshold of P < 0.2, to assess for associated factors. RESULTS: Of 402 patients with radiographically apparent solid fusion, 9.5% (38) subsequently suffered a broken rod. On multivariate analysis, greater rates of rod fracture were seen among patients of age group 60-69 years (vs. 18-49), body mass index 30-34 and 35+ (vs. <25), stainless-steel rods (vs. titanium), patients with rods ≤5.5 mm (vs. 6.35 mm), and patients with Charlson score 0 (vs. 3+). Of the 38 patients with rod fractures, 18 (47.4%) presented with worsened pain, and 8 (21.1%) required revision at minimum 2-year follow-up. CONCLUSIONS: Rod fracture occurred in 9.5% of patients with apparently solid radiographic fusion after ASD surgery. Advanced age, obesity, small diameter rods (5.5 mm), osteotomy, and lower comorbidity burden were significantly associated with rod fracture. Nearly one-half of these patients noted worsening pain, and 21.1% required revision surgery. Instrumentation failure may occur and may be symptomatic even in the setting of apparent fusion on plain radiographs.
Authors: Manuel Fernandes Marques; Vincent Fiere; Ibrahim Obeid; Yann-Philippe Charles; Khaled El-Youssef; Abi Lahoud; Joe Faddoul; Emmanuelle Ferrero; Guillaume Riouallon; Clément Silvestre; Jean-Charles Le Huec; David Kieser; Louis Boissiere Journal: Eur Spine J Date: 2021-05-05 Impact factor: 3.134