BioMed Research International

Review Article

The Current Testing Protocols for Biomechanical Evaluation of Lumbar Spinal Implants in Laboratory Setting: A Review of the Literature

Table 3

Summary of preload-torque protocol described in both single- and multisegmental studies.
(a) Single functional spinal unit
Spinal segment Number of articlesTorque [Nm] used at indicated preload
No preload mentioned0 [N]1–100 [N]200 [N]300 [N]400 [N]600 [N]700 [N]
T12-L12*6.02/7.5       
L1-L23*6.02/7.5  5.0 (e)    
L2-L37*5.0/6.02 
7.5		7.5/8.07.55.0 (e)   8
L3-L44*3.0/6.02 
7.5		  5.0 (e)    
L4-L57*5.0/6.02 
7.52		8.07.55.0 (e)   8
L5-sacrum1*6.0/7.5       
(b) Multiple functional spinal units
Spinal segment Number of articlesTorque [Nm] used at indicated preload
No preload mentioned0 [N]1–100 [N]200 [N]300 [N]400 [N]600 [N]700 [N]
T12-L21*7.5    7.5  
T12-L51(unspecified)       
T12-sacrum3*5.0/7.5H    H 
L1–L54* 3.5/5.0 
6.0/8.0		   5.0/6.0 
7.5/8.0		  
L1-sacrum11*2.5/5.0 
6.0/7.53 (H2)  
8.04 (H2)		5.02/6.02 
7.5/8.02		   2.5/5.02 
6.02/7.5 
8.03		  
L1-Pelvis26.0/8.0       
L2–L57*5.07.55 (H)/8.0   7.5  
L2-S8*7.56.0/7.5 
10.0 (H)		  10.0 (H)7.52, 8.03 (H)  
L3–L51* 7.5   7.5  
L3-S5*7.52/10.02 (H)8.0 (e)8.0 (e)     
L4-sacrum37.52 7.5     
One or more article described two or more testing protocols. This creates a discrepancy between “number of articles” and the number of preload-torque combinations described (i.e., the single-segment article that used L5-sacrum as their testing sample described two different protocols: (A) unspecified preload + 6.0 Nm of torque and (B) unspecified preload + 7.5 Nm of torque).
Superscripts refer to the number of articles describing the indicated load-torque combination.
e: eccentric loading; H: hybrid loading. (i.e., 8.04 (H2) = four articles described the used of 8.0 Nm, two of which used Hybrid loading).