Dynamic Stabilization Adjacent to Fusion versus Posterior Lumbar Interbody Fusion for the Treatment of Lumbar Degenerative Disease: A Meta-Analysis

Table 2

Newcastle-Ottawa scale (NOS).

Items	Scales
Categories	Herren et al. [19]	Aygun et al. [13]	Chen et al. [3]	Lee et al. [21]	Lu et al. [20]	Zhu et al. [8]	Lee et al. [22]	Liu et al. [9]	Putzier et al. [23]
Selection
(1) Is the case definition adequate?	1	1	1	1	1	1	1	1	1
(a) Yes, with independent validation.
(b) Yes, e.g., record linkage or based on self-reports.
(c) No description.
(2) Representativeness of the cases.	1	0	1	1	1	0	1	1	1
(a) Consecutive or obviously representative series of cases.
(b) Potential for selection biases or not stated
(3) Selection of controls.	1	1	1	1	1	1	1	1	1
(a) Community controls.
(b) Hospital controls.
(c) No description.
(4) Definition of controls.	1	1	1	1	1	1	1	1	1
(a) No history of disease (endpoint).
(b) No description of source.
Comparability
(1) Comparability of cases and controls on the basis of the design or analysis.	2	2	2	2	2	2	2	2	2
(a) Study controls for topping-off technique.
(b) Study controls for any additional factor.
Exposure
(1) Ascertainment of exposure.	1	0	0	1	0	0	0	0	0
(a) Secure record (e.g., surgical records).
(b) Structured interview where blind to case/control status.
(c) Interview not blinded to case/control status.
(d) Written self-report or medical record only.
(e) No description.
(2) Same method of ascertainment for cases and controls.	1	1	1	1	1	1	1	1	1
(a) Yes.
(b) No.
(3) Non-response rate.	1	0	0	0	0	0	0	0	0
(a) Same rate for both groups.
(b) Non respondents described.
(c) Rate different and no designation.
Total	9	6	7	8	7	6	7	7	7