J Korean Orthop Assoc.  2009 Feb;44(1):83-92. 10.4055/jkoa.2009.44.1.83.

Loss of Sagittal Balance and Clinical Outcomes following Corrective Osteotomy for Lumbar Degenerative Kyphosis

• Kim KT
• Lee SH
• Suk KS
• Lee JH
• Im YS
• Seo EM

• KMID: 2186382
• DOI: http://doi.org/10.4055/jkoa.2009.44.1.83

Abstract

PURPOSE: To report the loss of correction of a sagittal imbalance and the clinical outcomes after a corrective osteotomy for lumbar degenerative kyphosis.
MATERIALS AND METHODS
This study analyzed the radiological parameters, surgical techniques, and clinical outcomes of 23 patients, who underwent corrective osteotomy for lumbar degenerative kyphosis. The patients were divided into groups I (>5 cm loss of correction of sagittal imblance, 12 patients) and II (<5 cm, 11 patients) to compare the patients with the correction preserved with those with the correction lost. In terms of the clinical outcome, group A (high satisfaction score group >3.5 out of 5, 11 patients) was compared with group B (low satisfaction score group <3.5 out of 5, 12 patients).
RESULTS
The sagittal imbalance was corrected by performing a Smith-Petersen osteotomy (SPO) in 11 cases and Pedicle subtraction osteotomy (PSO) in 12. The mean preoperative sagittal imbalance was improved from 26.4 cm to 4.05 cm, postoperatively, and 11.2 cm at the last follow up. The mean loss of correction was 11.2 cm in group I and 2.3 cm in group II. The mean satisfaction score was 4.56 in group A and 2.18 in group B. The presence of an old compression fracture was found to be related to the loss of correction, and the preoperative symptomatic spinal stenosis was related to poor clinical outcomes.
CONCLUSION
After mean 45 month follow up, the mean loss of sagittal correction was 38.3%, which mainly occurred at the proximal unfused segment. The clinical success rate was 45.5%, regardless of the loss of sagittal balance correction.

Keyword

Lumbar degenerative kyphosis; Sagittal imbalance

MeSH Terms

Follow-Up Studies
Fractures, Compression
Humans
Kyphosis
Osteotomy
Spinal Stenosis

Figure

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  Fig. 1 Radiographs after the Smith-Peterson osteotomy with anterior lumbar interbody fusion (A) and Pedicle subtraction osteotomy (B) in lumbar degenerative kyphosis patients.

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  Fig. 2 Schematic diagram showing a sagittal imbalance (SI), SI1 and SI2.

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  Fig. 3 Radiographs showing LDK patients with reactive thoracic lordosis (A) and without reactive thoracic lordosis (B).

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  Fig. 4 Serial radiographs of a 72-year-old female patient showing loss of sagittal balance. (A) Preoperative radiograph showing severe sagittal imbalance (35.5 cm). (B) Immediate postoperative radiographs showing a restoration of the sagittal balance (4.5 cm). Note the line from the posterosuperior corner of S1 to the center of the T12/L1 disc passes in front of T1. (C) Two years after surgery, the sagittal balance was lost (19.2 cm). The same line of (B) passes in back of T1. This suggests that a significant loss of correction occurred at the proximal unfused segments.

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  Fig. 5 Serial radiographs of a 74-year-old female patient showing severe loss of correction 46 months after surgery. Most of the loss occurred at proximal unfused segment with degenerative changes.

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