J Korean Soc Spine Surg.  2009 Sep;16(3):177-185. 10.4184/jkss.2009.16.3.177.

Radiologic Analysis of Postoperative Sagittal Plane Correction in Lumbar Degenerative Kyphosis (LDK)

Affiliations
  • 1Department of Orthopaedic Surgery, Eulji University School of Medicine, Korea. jwkang@eulji.ac.kr
  • 2Daejeon Veterans Hospital, Korea.
  • 3Hongseong Medical Center, Korea.
  • 4Gimcheon Jeil Hospital, Korea.

Abstract

STUDY DESIGN: This is a retrospective study OBJECTIVES: We radiologically analyzed the correction of the sagittal imbalance and the proximal fusion level to prevent correction loss and the usefulness of iliac screws in LDK. SUMMARY OF THE LITERATURE REVIEW: Complications can be encountered during fixation and fusion as most of the LDK patients are aged, and the osteoporosis that causes fixation loss is known to affect the loss of correction.
MATERIALS AND METHODS
We analyzed the cause of correction loss among 35 patients who underwent surgery and who were followed up for at least 1 year. All the patients had performed gait analysis before operation. The operative techniques were pedicle subtraction osteotomy and fixation to S1. For analyzing causes of correction loss, we analyzed the degrees of lumbar lordosis for the sagittal correction and the degrees of the preoperative thoracolumbar kyphosis for the proximal fusion range. For analyzing the usefulness of iliac screws, the subjects were divided into two groups: 1) the -iliac screw (23cases) group for the patients who were fixed without iliac screws and 2) the +iliac screw (12cases) group for the patients who were fixed with iliac screws.
RESULTS
There were no patients who had marked anterior pelvic tilt. It is important to correct the lumbar lordosis over 20degrees compared with the preoperative thoracic kyphosis. There are 10 cases of preoperative thoracolumbar kyphosis > or = 10degrees and 25 cases of preoperative thoracolumbar kyphosis < 10degrees of the total 35 cases. Among 10 cases of preoperative thoracolumbar kyphosis > or = 10degrees, 4 cases that were fixed to T10 had no sagittal correction loss, and 2 of the 6 cases that were fixed to T11 or T12 had sagittal correction loss. For the 25 cases of preoperative thoracolumbar kyphosis < 10degrees, 5 cases that were fixed to T10 had no sagittal correction loss and 1 of the 20 cases that were fixed to T11 or T12 had sagittal correction loss (p<0.05). 6 cases (26%) in the -iliac screw group (23 cases total) and 1 case (8%) in the +iliac screw (12 cases total) showed sagittal correction loss (p<0.05).
CONCLUSIONS
It is important to make the postoperative lumbar lordosis over 20degrees compared with the preoperative thoracic kyphosis for correcting sagittal imbalance, to decide on the proximal fixation level according to the preoperative thoracolumbar kyphosis and to fix with iliac screws.

Keyword

Lumbar degenerative kyphosis; Iliac screw; Sagittal plane correction loss

MeSH Terms

Aged
Animals
Gait
Humans
Kyphosis
Lordosis
Osteoporosis
Osteotomy
Retrospective Studies
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