Transpedicular lumbar wedge resection osteotomy for fixed sagittal imbalance: surgical technique and early results.

STUDY DESIGN: A retrospective consecutive case series, radiographic analysis, outcomes analysis, and report on complications. OBJECTIVES: To evaluate the radiographic and functional outcomes of a reconstructive realignment procedure for fixed sagittal imbalance and discuss the complications. SUMMARY OF BACKGROUND DATA: We describe a modification of an existing technique permitting greater single-level correction for which no reports exist in the peer-reviewed literature. METHODS: Twenty-four patients were eligible for 2-year minimum follow-up (average, 4.0 years). Etiologies included iatrogenic (n = 17), post-traumatic (n = 3), ankylosing spondylitis (n = 2), degenerative (n = 1), and congenital (n = 1). Patients were evaluated by standardized upright radiographs, chart review, and National Spine Network questionnaire. RESULTS: Seventeen patients had undergone 17 previous procedures. Seven of 24 patients required augmentation with anterior structural grafting. The majority of osteotomies were performed at L3 (15); others included L2 (6), L4 (2), and L5 (1). Lumbar lordosis before surgery averaged 13 degrees (range, 55 degrees to -65 degrees) and improved to 53 degrees (range, 20 degrees to 99 degrees), an average correction of 40%. The sagittal vertical axis measured from C7-S1 demonstrated a preoperative sagittal decompensation averaging 11.4 cm (range, 5.5-23 cm) with correction to 2.4 cm (-9.0 cm or 79% average correction). Coronal balance did not change significantly. There were 17 complications in 14 patients. Nine patients required additional surgery at latest follow-up. CONCLUSIONS: Transpedicular wedge resection osteotomy procedure is a very effective technique to correct fixed sagittal imbalance and provide biomechanical stability. The high complication rate mandates a careful assessment of the risk/benefit ratio before undertaking what is a major reconstructive procedure. Most patients are satisfied, particularly when sagittal balance is achieved.

Not all spondylolisthesis grading instruments are reliable.

Spondylolisthesis is the slippage of one vertebral body on an adjacent level, and occurs commonly at the lumbosacral junction in children. Many radiographic measurement instruments have been described to predict progression and need for intervention. We evaluated the reliability of eight common grading instruments. Four raters reviewed 30 lateral radiographs of the lumbar spine in patients with spondylolisthesis. Each rater measured each film twice, and had mean individual correlation coefficients of at least 0.76 (range, 0.76-0.91). Only three measurements had interobserver correlations greater than 0.75 (slip percentage, Meyerding's grade, and sacral inclination), which corresponded to excellent reliability. For intraobserver reliability, six measurements had correlations greater than 0.75 (all except kyphosis angle and lumbar index), indicating excellent agreement. Slip percent, Meyerding's grade, and sacral inclination had excellent interobserver agreement and intraobserver agreement.