Browsing by Author "Novicoff, Wendy M"

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    ItemOpen Access
    Failure of lumbopelvic fixation after long construct fusions in patients with adult spinal deformity: clinical and radiographic risk factors: clinical article.
    (Journal of neurosurgery. Spine, 2013-10) Cho, Woojin; Mason, Jonathan R; Smith, Justin S; Shimer, Adam L; Wilson, Adam S; Shaffrey, Christopher I; Shen, Francis H; Novicoff, Wendy M; Fu, Kai-Ming G; Heller, Joshua E; Arlet, Vincent

    Object

    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.

    Methods

    This retrospective review included 190 patients with adult spinal deformity who had long construct instrumentation (> 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.

    Results

    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.

    Conclusions

    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.
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    ItemOpen Access
    Selective versus nonselective fusion for idiopathic scoliosis: does lumbosacral takeoff angle change?
    (Spine, 2011-06) Abel, Mark F; Herndon, Stephanie K; Sauer, Lindsay D; Novicoff, Wendy M; Smith, Justin S; Shaffrey, Christopher I; Spinal Deformity Study Group

    Study design

    Retrospective review of a prospective, multicentered database.

    Objective

    To determine the relationship between preoperative lumbosacral takeoff angle (LSTOA) and postoperative thoracolumbar/lumbar Cobb angle (TL/L Cobb angle) in patients undergoing selective thoracic fusions

    Summary of background data

    Selective fusion of the thoracic curve can improve the lumbar curve inpatients with idiopathic thoracic scoliosis and a compensatory lumbar curve. Predicting improvement is controversial and determining whether to perform a selective fusion or nonselective fusion can be difficult.

    Methods

    Patients had undergone either nonselective or selective spinal fusion for adolescent or juvenile idiopathic scoliosis (Lenke 1B/3B/1C/3C). Outcome measures were: coronal and sagittal thoracic Cobb angle, TL/L Cobb angles, lumbar apical vertebral translation, LSTOA and coronal decompensation. Analyses compared relationships between preoperative and postoperative radiographic measures.

    Results

    Positive, significant correlations were found between preoperative LSTOA and preoperative TL/L Cobb angle in the nonselective (r=0.7; P<0.001) and selective (r=0.5; P<0.001) fusion groups. Mean two-year postoperative coronal TL/L Cobb angles were significantly improved in nonselective and selective fusion groups (32° and 20°, respectively, P<0.001). In the nonselective fusion group, LSTOA significantly decreased by 11° (P<0.001), and in the selective group, the LSTOA had a modest but significant decrease of 2° (P<0.001). The nonselective fusion also resulted in more lordosis between T10 and L2 (7.5° of lordosis) than the selective approach (2.7° kyphosis, P<0.001). For both groups, upper thoracic kyphosis increased after surgery (P<0.001, P<0.001). For nonselective fusions, regression modeling predicted TL/L Cobb angle at two-year follow-up based on preoperative TL/L Cobb angle and preoperative LSTOA (r=0.4, P<0.001).

    Conclusion

    Collectively, these data demonstrate the preoperative TL/L Cobb angle and LSTOA can be useful predictors of postoperative TL/L Cobb angle after a selective instrumented fusion. Analyses of distal fixation levels demonstrated that to appreciably change the LSTOA using a posterior instrumented fusion, the distal level of fixation must be beyond the lumbar apex.