Does the lower instrumented vertebra have an effect on lumbar mobility, subjective perception of trunk flexibility, and quality of life in patients with idiopathic scoliosis treated by spinal fusion?

STUDY

DESIGN

Cross-sectional study in patients with idiopathic scoliosis treated with spinal fusion.

OBJECTIVES

To measure lumbar spine mobility in the study population; determine low back pain intensity (LBPi), subjective perception of trunk flexibility (TF), and quality of life using validated outcome instruments; and investigate correlations of the lower instrumented vertebra (LIV) with TF, LBPi, and quality of life.

SUMMARY OF BACKGROUND DATA: The loss of range of motion resulting from spinal fusion might lead to low back pain, trunk rigidity, and a negative impact on quality of life. Nonetheless, these outcomes have not been conclusively demonstrated because lumbar mobility and LIV have not been correlated with validated outcome instruments.

METHODS

Forty-one patients (mean age, 27 y) with idiopathic scoliosis treated by spinal fusion (mean time since surgery, 135 mo) were included. Patients were assigned to 3 groups according to LIV level: group 1 (fusion to T12, L1, or L2) 14 patients; group 2 (fusion to L3) 13 patients, and group 3 (fusion to L4, L5, or S1) 14 patients. At midterm follow-up, patients completed the Scoliosis Research Society (SRS)-22 Questionnaire and Quality of Life Profile for Spine Deformities to evaluate perceived TF, and rated LBPi with a numerical scale. Lumbar mobility was assessed using a dual digital inclinometer.

RESULTS

Group 3 (fusion to L4, L5, or S1) showed statistically significant differences relative to the other groups, with less lumbar mobility and poorer scores for the SRS subtotal (P = 0.003) and SRS pain scale (P = 0.01). Nevertheless, LBPi and TF were similar in the 3 groups. TF correlated with SRS-22 subtotal (r = -0.38, P = 0.01) and pain scale (r = -0.42, P = 0.007) scores, and with LBPi (r = 0.43, P = 0.005).

CONCLUSIONS

LIV correlated moderately with lumbar mobility, health-related quality of life (SRS-22), and spinal pain (SRS-22 pain subscale), but not with intensity of pain in the lumbar area or perceived TF.