Changes in vitamin D status after surgery in female patients with lumbar spinal stenosis and its clinical significance.
METHODS
A prospective cohort study.


OBJECTIVE
To demonstrate the changes in vitamin D status after surgery in female patients with lumbar spinal stenosis (LSS), and its correlation with surgical outcomes.


BACKGROUND
In patients with LSS, general health including walking ability and nutritional status can be markedly improved by decompressive surgery. It can be hypothesized that such improvement may have a positive effect on their vitamin D status.


METHODS
In total, 31 female patients who underwent decompression and instrumented posterolateral fusion for LSS were enrolled. Serum 25-hydroxyvitamin D (25-OHD) level was measured before the surgery and at 1 year postoperative visit. According to serum 25-OHD level, patients were classified into 3 groups: (1) deficient group, when 25-OHD level was less than 20 ng/mL (< 50 nmol/L); (2) insufficient group, when 25-OHD level was between 20 to 30 ng/mL (50 nmol/L ≤ 25-OHD < 75 nmol/L); (3) and normal group, when 25-OHD level was 30 ng/mL or more (≥ 75 nmol/L). The Oswestry Disability Index (ODI) score and health-related quality of life (EQ-5D) were compared according to the level of 25-OHD at 1 year postoperatively.


RESULTS
Preoperatively, there were 20 patients in the deficient group, 11 patients in the insufficient group and no patient in the normal group. There were no differences in age, body mass index, preoperative ODI scores, preoperative EQ-5D index scores, and EQ-5D visual analogue scale scores between the 2 groups. Mean preoperative 25-OHD level was 15.8 ng/mL (range, 5.2-29.4 ng/mL) and increased to 19.5 ng/mL (range, 6.3-47.7 ng/mL) 1 year after surgery (P = 0.075). Significant increase of 25-OHD was noted only in the deficient group (P = 0.017). Postoperatively, there were 18 patients in the deficient group, 8 patients in the insufficient group, and 5 patients in the normal group. In the postoperative deficient group, postoperative ODI scores and EQ-5D index scores showed significantly worse outcomes than those in the other groups. The changes in serum 25-OHD level were significantly correlated with the changes in ODI scores (r = -0.580; P = 0.001) and with the changes in EQ-5D index scores (r = 0.379; P = 0.035). In all the groups, postoperative ODI scores (r = -0.665; P < 0.001) and EQ-5D index scores (r = 0.601; P < 0.001) were significantly correlated with postoperative 25-OHD level.


CONCLUSIONS
Vitamin D deficiency was common in patients with LSS. However, vitamin D status was improved after decompressive surgery, and postoperative 25-OHD level was significantly correlated with surgical outcomes.
Department of Orthopedic Surgery, Yonsei University College of Medicine, Seoul, Korea.
Tae-Hwan
TH
Kim
Ji Young
JY
Yoon
Byung Ho
BH
Lee
Hyun-Soo
HS
Jung
Moon Soo
MS
Park
Jin-Oh
JO
Park
Eun-Su
ES
Moon
Hak-Sun
HS
Kim
Hwan-Mo
HM
Lee
Seong-Hwan
SH
Moon
D000368:Aged; D019299:Decompression, Surgical; D004185:Disability Evaluation; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008159:Lumbar Vertebrae / Q000601:surgery*; D008875:Middle Aged; D017063:Outcome Assessment, Health Care / Q000706:statistics & numerical data; D011184:Postoperative Period; D057234:Preoperative Period; D011446:Prospective Studies; D011788:Quality of Life; D013123:Spinal Fusion; D013130:Spinal Stenosis / Q000097:blood* / Q000601:surgery*; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood
D014807:Vitamin D; C104450:25-hydroxyvitamin D