Uncorrected sagittal plane imbalance predisposes to symptomatic instrumentation failure

• Published in: The spine journal Vol. 8; no. 6; pp. 911 - 917
• Main Authors: Gilad, Ronit, MD, Gandhi, Chirag D., MD, Arginteanu, Marc S., MD, Moore, Frank M., MD, Steinberger, Alfred, MD, Camins, Martin, MD
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.11.2008
• Subjects: Adult; Age Distribution; Aged; Aged, 80 and over; Cobb angle; Female; Foreign-Body Migration - diagnostic imaging; Foreign-Body Migration - epidemiology; Humans; Internal Fixators - adverse effects; Internal Fixators - statistics & numerical data; Male; Middle Aged; Orthopedics; Osteoporosis - diagnostic imaging; Osteoporosis - epidemiology; Osteoporosis - surgery; Postoperative Complications - diagnostic imaging; Postoperative Complications - epidemiology; Prosthesis Failure; Pseudarthrosis; Pseudarthrosis - diagnostic imaging; Pseudarthrosis - epidemiology; Radiography; Retrospective Studies; Risk Factors; Sagittal plane; Smoking - epidemiology; Spinal Diseases - diagnostic imaging; Spinal Diseases - epidemiology; Spinal Diseases - surgery; Spinal Fusion - adverse effects; Spinal Fusion - instrumentation; Spinal Fusion - statistics & numerical data; Spinal instrumentation; Spine deformity; Young Adult; Pseudarthrosis; Spinal instrumentation; Spine deformity; Sagittal plane; Cobb angle
• ISSN: 1529-9430; 1878-1632
• DOI: 10.1016/j.spinee.2007.10.035

Abstract Background context Elucidation of the factors responsible for symptomatic failure of spinal instrumentation has been a keen interest for many investigators. Purpose To quantitate the number of symptomatic instrumentation failures (SIFs) encountered during a 2-year period. The effect of sagittal plane imbalance (corrected or uncorrected) on the rate of SIF was evaluated. Study design Retrospective evaluation of all patients requiring spinal instrumentation to determine which factors predispose toward instrumentation failure. Patient sample All patients requiring spinal instrumentation over a 2-year period were retrospectively studied. Outcome measures Sagittal plane imbalance pre- and postoperatively was determined using Cobb angle analysis on plain X-rays. SIF was defined as screw back-out and/or breakage, pseudarthrosis, cage migration, or rod disconnection in patients with concordant symptoms. Asymptomatic patients did not demonstrate instrumentation failure on the routine postoperative X-rays. Methods Of the 355 patients who fit the criteria, 47 patients presented with either idiopathic or secondary sagittal plane deformity preoperatively. Additionally, long-segment fixation, smoking, age, and fixation across junctional segments were evaluated as risk factors for SIF. Results Of the 47 patients with sagittal plane deformity, 40 patients (85%) achieved correction demonstrated on postoperative radiographs whereas in 7 (15%), the sagittal plane imbalance was not corrected. Of these seven cases, five suffered instrumentation failure (failure rate 71.5%) versus no instrumentation failures (failure rate 0%) for the remaining 40 patients. SIF was demonstrated in 10 patients overall (failure rate of 2.8%). There was no correlation found between factors such as age, indications for surgery, or long-segment fixation, and instrumentation failure. Conclusions Failure to correct sagittal plane deformity intraoperatively predisposes patients to SIF regardless of age, level of surgery, or indication of surgery.