Failure of lumbopelvic fixation after long construct fusions in patients with adult spinal deformity: clinical and radiographic risk factors

Abstract

<jats:sec> <jats:title>Object</jats:title> <jats:p>Lumbopelvic fixation provides biomechanical support to the base of the long constructs used for adult spinal deformity. However, the failure rate of the lumbopelvic fixation and its risk factors are not well known. The authors' objective was to report the failure rate and risk factors for lumbopelvic fixation in long instrumented spinal fusion constructs performed for adult spinal deformity.</jats:p></jats:sec> <jats:sec> <jats:title>Methods</jats:title> <jats:p>This retrospective review included 190 patients with adult spinal deformity who had long construct instrumentation (&gt; 6 levels) with iliac screws. Patients' clinical and radiographic data were analyzed. The patients were divided into 2 groups: a failure group and a nonfailure group. A minimum 2-year follow-up was required for inclusion in the nonfailure group. In the failure group, all patients were included in the study regardless of whether the failure occurred before or after 2 years. In both groups, the patients who needed a revision for causes other than lumbopelvic fixation (for example, proximal junctional kyphosis) were also excluded. Failures were defined as major and minor. Major failures included rod breakage between L-4 and S-1, failure of S-1 screws (breakage, halo formation, or pullout), and prominent iliac screws requiring removal. Minor failures included rod breakage between S-1 and iliac screws and failure of iliac screws. Minor failures did not require revision surgery. Multiple clinical and radiographic values were compared between major failures and nonfailures.</jats:p></jats:sec> <jats:sec> <jats:title>Results</jats:title> <jats:p>Of 190 patients, 67 patients met inclusion criteria and were enrolled in the study. The overall failure rate was 34.3%; 8 patients had major failure (11.9%) and 15 had minor failure (22.4%). Major failure occurred at a statistically significant greater rate in patients who had undergone previous lumbar surgery, had greater pelvic incidence, and had poor restoration of lumbar lordosis and/or sagittal balance (that is, undercorrection). Patients with a greater number of comorbidities and preoperative coronal imbalance showed trends toward an increase in major failures, although these trends did not reach statistical significance. Age, sex, body mass index, smoking history, number of fusion segments, fusion grade, and several other radiographic values were not shown to be associated with an increased risk of major failure. Seventy percent of patients in the major failure group had anterior column support (anterior lumbar interbody fusion or transforaminal lumbar interbody fusion) while 80% of the nonfailure group had anterior column support.</jats:p></jats:sec> <jats:sec> <jats:title>Conclusions</jats:title> <jats:p>The incidence of overall failure was 34.3%, and the incidence of clinically significant major failure of lumbopelvic fixation after long construct fusion for adult spinal deformity was 11.9%. Risk factors for major failures are a large pelvic incidence, revision surgery, and failure to restore lumbar lordosis and sagittal balance. Surgeons treating adult spinal deformity who use lumbopelvic fixation should pay special attention to restoring optimal sagittal alignment to prevent lumbopelvic fixation failure.</jats:p></jats:sec>

Long fusion from sacrum to thoracic spine for adult spinal deformity with sagittal imbalance: upper versus lower thoracic spine as site of upper instrumented vertebra

“…3,10,18,23 Additionally, complications are not uncommon. Cho et al reported that the complication rate for degenerative lumbar scoliosis was 68%.…”

Unplanned reoperation after lumbopelvic fixation with S-2 alar-iliac screws or iliac bolts

“…A recent review, however, included failure at the level above the lumbosacral junction (L4-5) as a major complication of pelvic fixation. 8 This phenomenon may occur because of construct failure originating at either the rostral or caudal end. Possible mechanisms of both types of failure are described below.…”

“…34 Three of the 37 patients (8%) in our study who received iliac bolts underwent removal of the pelvic fixation because of painful hardware prominence, which is consistent with the rates of iliac bolt removal reported in other studies (3%-34%). 8,15,17,24,34 The rate of patients experiencing pain relief after implant removal varies widely (12%-70%). 2,3,10,13,31 Removal of instrumentation is not a benign procedure, and previous studies have reported progression of deformity after removal.…”

Accuracy Analysis of Iliac Screw Using Freehand Technique in Spinal Surgery : Relation between Screw Breach and Revision Surgery

“…Screw loosening, represented as a radiolucent area around the screw, indicates loss of screw fixation and potential progression to pseudarthrosis 1,17) . The prevalence of iliac screw loosening after long spinal fusion is known to be particularly high (7.5-52%) 3,11,22) . In this study, the iliac screw loosening incidence rate (15/193 screws, 7.8%) was similar to that of a previous report.…”