Clinical outcomes and complications after pedicle subtraction osteotomy for fixed sagittal imbalance patients : a long-term follow-up data

Abstract

Objective: Clinical, radiographic, and outcomes assessments, focusing on complications, were performed in patients who underwent pedicle subtraction osteotomy (PSO) to assess correction effectiveness, fusion stability, procedural safety, neurological outcomes, complication rates, and overall patient outcomes.

Methods: We analyzed data obtained from 13 consecutive PSO-treated patients presenting with fixed sagittal imbalances from 1999 to 2006. A single spine surgeon performed all operations. The median follow-up period was 73 months (range 41-114 months). Events during perioperative course and complications were closely monitored and carefully reviewed. Radiographs were obtained and measurements were done before surgery, immediately after surgery, and at the most recent follow-up examinations. Clinical outcomes were assessed using the Oswestry Disability Index and subjective satisfaction evaluation.

Results: Following surgery, lumbar lordosis increased from -14.1 degrees +/- 20.5 degrees to -46.3 degrees +/- 12.8 degrees (p < 0.0001), and the C7 plumb line improved from 115 +/- 43 mm to 32 +/- 38 mm (p < 0.0001). There were 16 surgery-related complications in 8 patients; 3 intraoperative, 3 perioperative, and 10 late-onset postoperative. The prevalence of proximal junctional kyphosis (PJK) was 23% (3 of 13 patients). However, clinical outcomes were not adversely affected by PJK. Intraoperative blood loss averaged 2,984 mL. The C7 plumb line values and postoperative complications were closely correlated with clinical results.

Conclusion: Intraoperative or postoperative complications are relatively common following PSO. Most late-onset complications in PSO patients were related to PJK and instrumentation failure. Correcting the C7 plumb line value with minimal operative complications seemed to lead to better clinical results.

Keywords: Clinical outcome; Complication; Pedicle subtraction osteotomy; Proximal junctional kyphosis; Sagittal imbalance.

Fig. 1

A representative example of pedicle subtraction osteotomy (PSO) for fixed sagittal imbalance patients. A : Lateral long-cassette standing radiograph of a 60-year-old woman who presented with severe lower back pain and a stooping gait revealed global degenerative sagittal imbalance. B : The patient underwent L4 PSO with anterior column support, and the plain film obtained at her most recent follow-up examination shows dramatic improvement in lumbar kyphosis.

Fig. 2

Subjective satisfaction evaluation of final surgical results showing acceptable clinical outcomes.

Fig. 3

Preoperative (A) and postoperative (B-E) radiographs of a 62-year-old woman. The patient presented with intolerable lower back pain and stooping symptoms. B : Pedicle subtraction osteotomy at L3, transforaminal interbody fusion at L4-5, and a posterior fusion from T12 to S1, were performed. C and D : Three years postoperatively, rod fracture (black arrow) and haloing (white arrow) around the S1 screws occurred. E : Loose screws were replaced, the posterior construct was extended to include iliac screws, and interbody grafts were inserted to support the anterior column.