J Korean Soc Spine Surg.  2005 Sep;12(3):184-191. 10.4184/jkss.2005.12.3.184.

The Influence of the Degree of Lumbar Disc Degeneration on MRI and the Amount of Removed Disc on Clinical Outcomes

• Lee KY
• Sohn SK
• Lee MJ
• Chung IK

• KMID: 1941683
• DOI: http://doi.org/10.4184/jkss.2005.12.3.184

Abstract

STUDY DESIGN: The influence of lumbar disc degeneration, the space-occupying ratio on MRI and the amount of removed disc on the clinical outcomes of an open discectomy were analyzed retrospectively.
OBJECTIVES
This study analyzed the pre and post-operative factors associated with the clinical outcome of an open discectomy. SUMMARY OF LITERATURE REVIEW: Much controversy still exists regarding the factors that influence the clinical outcome following an open discectomy.
MATERIALS AND METHODS
Out of 207 patients who had been treated with an open discectomy for a lumber disc herniation, between April 1997 and December 2003, 161 patients who underwent MRI with the same apparatus, with at least 6 months of follow-up, were analyzed. The study group was composed of 111 men and 50 women, with a mean age at the time of surgery of 33.1 years old. The mean follow-up period was 42 months. The degree of disc degeneration was classified according to the Thompson's classification, and the extent of the discectomy was measured by the volume. The postoperative outcomes were judged using Nayer's classification.
RESULTS
The highest frequency of disc herniation occurred at the L4-5 level, with being of the subligamentous extrusion type. The disc degeneration observed on MRI had a high statistical correlation with age (p<0.001); however, there was no statistical relationship with the level of disc herniation, sex and the amount of disc removed by discectomy (p>0.05). Clinically, 123 cases were more than fair, and 4 cases underwent reoperation due to recurrence. The clinical outcome, sex, age and space-occupying ratio were of little statistical value (p>0.05). Statistically, the greater the amount of disc removed, the better the clinical outcome (p<0.05). Those with disc degeneration classified as grade 3 from the MRI had unsatisfactory clinical outcomes (p<0.05).
CONCLUSIONS
Those with disc degeneration classified as grade 3 from the MRI had unsatisfactory clinical outcomes. The greater the amount of disc removed the more satisfactory the clinical outcomes. No statistical relationships were found between the space-occupying ratio and the clinical outcome.

Keyword

Lumbar disc herniation; Disc degeneration; Discectomy; Clinical outcome

MeSH Terms

Classification
Diskectomy
Female
Follow-Up Studies
Humans
Intervertebral Disc Degeneration*
Magnetic Resonance Imaging*
Male
Recurrence
Reoperation
Retrospective Studies

Figure

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  Fig. 1. Assessment of the degree of disc degeneration using the five grade scale of Thompson.

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  Fig. 2. Measurement method for space-occupying ration The space-occupying ration of the herniated material to the spinal canal. B/A× 100 on axial images was calcuated

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  Fig. 3. Correlation between disc volume of discectomy and clinical result.

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