The Neck Disability Index (NDI) and its correlation with quality of life and mental health measures among patients with single-level cervical disc disease scheduled for surgery.
BACKGROUND
The Neck Disability Index (NDI) is widely used as a self-rated disability score in patients with cervical radiculopathy. The purpose of this study was to evaluate whether the NDI score correlated with other assessments of quality of life and mental health in a specific group of patients with single-level cervical disc disease and corresponding radiculopathy.


METHODS
One hundred thirty-six patients were included in a prospective, randomized controlled clinical multicenter study on one-level anterior cervical discectomy with arthroplasty (ACDA) versus one-level anterior cervical discectomy with fusion (ACDF). The preoperative data were obtained at hospital admission 1 to 3 days prior to surgery. The NDI score was used as the dependent variable and correlation as well as regression analyses were conducted to assess the relationship with the short form-36, EuroQol-5Dimension-3 level and Hospital Anxiety and Depression Scale.


RESULTS
The mean age at inclusion was 44.1 years (SD ±7.0, range 26-59 years), of which 46.3 % were male. Mean NDI score was 48.6 (SD = 12.3, minimum 30 and maximum 88). Simple linear regression analysis demonstrated a significant correlation between NDI and the EuroQol-5Dimension-3 level [R = -0.64, 95 % confidence interval (CI) -30.1- -19.8, p < 0.001] and to a lesser extent between NDI and the short form-36 physical component summary [R = -0.49, 95 % CI (-1.10- -0.58), p < 0.001] and the short form-36 mental component summary [R = -0.25, 95 % CI (-0.47- -0-09), p = 0.004]. Regarding NDI and the Hospital Anxiety and Depression Scale, a significant correlation for depression was found [R = 0.26, 95 % CI (0.21-1.73), p = 0.01]. Multiple linear regression analysis showed a statistically significant and the strongest correlation between NDI and the independent variables in the following order: EuroQol-5Dimension-3 level [R = -0.64, 95 % CI (-23.5- -7.9), p <0.001], short form-36 physical component summary [R = -0.41, 95 % CI (-0.93- -0.23), p = 0.001] and short form-36 mental component summary [R = -0.36, 95 % CI (-0.53- -0.15), p = 0.001].


CONCLUSIONS
The results from the present study show that the NDI correlated significantly with a different quality of life and mental health measures among patients with single-level cervical disc disease and corresponding radiculopathy.
Department of Neurosurgery, Oslo University Hospital Rikshospitalet, Postboks 4950, Nydalen, 0424, Oslo, Norway. jsundset@ous-hf.no.|Institute of Clinical Medicine, University of Oslo, Oslo, Norway. jsundset@ous-hf.no.
J
J
Sundseth
Department of Neurosurgery, Oslo University Hospital Rikshospitalet, Postboks 4950, Nydalen, 0424, Oslo, Norway.
F
F
Kolstad
Neuroclinic, Center of Spinal Disorder and Department of Orthopedic Surgery, Clinic of Orthopaedics and Rheumatology, St. Olavs Hospital, Trondheim University Hospital, Trondheim, Norway.
L G
LG
Johnsen
Department of Biostatistics, Epidemiology and Health Economics, Oslo University Hospital, Oslo, Norway.
A H
AH
Pripp
National resource center for spinal disorders, University Hospital of Trondheim (St Olavs Hospital HF), Trondheim, Norway.|Department of Neurosurgery, University Hospital of Trondheim (St Olavs Hospital HF), Trondheim, Norway.
O P
OP
Nygaard
National resource center for spinal disorders, University Hospital of Trondheim (St Olavs Hospital HF), Trondheim, Norway.
H
H
Andresen
Department of Neurosurgery, University Hospital of Trondheim (St Olavs Hospital HF), Trondheim, Norway.|University of Trondheim, Trondheim, Norway.
O A
OA
Fredriksli
Department of Neurosurgery, Haukeland University Hospital, Bergen, Norway.
E
E
Myrseth
Department of Neurosurgery, Oslo University Hospital Rikshospitalet, Postboks 4950, Nydalen, 0424, Oslo, Norway.
M
M
Züchner
Institute of Clinical Medicine, University of Oslo, Oslo, Norway.|Department of Neurology and FORMI, Oslo University Hospital Ullevaal, Oslo, Norway.
J A
JA
Zwart
D000328:Adult; D000368:Aged; D002574:Cervical Vertebrae / Q000473:pathology* / Q000601:surgery; D005260:Female; D006801:Humans; D055959:Intervertebral Disc Degeneration / Q000473:pathology / Q000601:surgery; D007405:Intervertebral Disc Displacement / Q000473:pathology / Q000601:surgery; D008297:Male; D008603:Mental Health; D008875:Middle Aged; D011788:Quality of Life; D012720:Severity of Illness Index
Anxiety; Cervical radiculopathy; Depression; Neck Disability Index; Quality of life