Disc height and segmental motion as risk factors for recurrent lumbar disc herniation.

STUDY DESIGN

Retrospective review and multivariate analysis.

OBJECTIVES

Recurrent lumbar disc herniation (rLDH) is a repeated disc herniation at a previously operated disc level in patients who experienced a pain-free interval of at least 6 months after surgery. We investigated whether the preoperative radiologic biomechanical factors (disc height index [DHI] and sagittal range of motion [sROM]) have any effect on rLDH.

SUMMARY OF BACKGROUND DATA

rLDH has been reported in 5% to 15% of patients. There have been many studies suggesting various risk factors for rLDH, such as disc degeneration, trauma, age, smoking, gender, and obesity. However, these factors did not reflect a biomechanical effect on the affected joint directly. Investigation of DHI and sROM would be helpful to understand the biomechanical impact on the occurrence of rLDH.

METHODS

This study enrolled 157 patients who underwent surgery for L4-L5 LDH. We divided the patients into the recurrent and the nonrecurrent group and compared their clinical parameters (age, sex, body-mass index, symptom duration, diabetes, smoking, herniation type, preoperative visual analogue scale) and preoperative radiologic parameters (disc degeneration, DHI, sROM).

RESULTS

rLDH occurred at 40.8+/-15.5 months (7-70 months) after primary surgery. Mean DHI was 0.37+/-0.09 and 0.29+/-0.09 in the recurrent and the nonrecurrent group, respectively (P<0.05). Mean sROM was 11.3 degrees+/-2.9 degrees and 5.9 degrees+/-3.7 degrees in the recurrent and the nonrecurrent group, respectively (P<0.05). Both smoking and disc degeneration were related with the development of rLDH (P<0.05).

CONCLUSION

Together with our data, DHI and sROM showed a significant correlation with the incidence of recurrent lumbar disc herniation, suggesting that preoperative biomechanical conditions of the spine can be an important pathogenic factor in the site of lumbar disc surgery.