Marmarou Weight Drop Injury Model

Author(s):  
Christina R. Marmarou ◽  
Ruth Prieto ◽  
Keisuke Taya ◽  
Harold F. Young ◽  
Anthony Marmarou
Keyword(s):  
1983 ◽  
Vol 59 (2) ◽  
pp. 268-275 ◽  
Author(s):  
Ronald W. J. Ford

✓ Allen's weight-drop method for producing experimental spinal cord injuries was improved by placing a curved stainless steel plate anterior to the spinal cord to provide a smooth, hard surface for the receipt of posterior cord impact. In addition, an electronic circuit was used to ensure that cord injury was produced by a single impact, thereby enhancing the reproducibility of the injury mechanism. Using a spinal cord injury model with these modifications, the author found that the recovery of hindlimb function and the histopathological appearance of the injured cord 6 weeks after upper lumbar injury were closely related to injury magnitude. The curve of functional recovery versus injury magnitude has a sharp transition centered at 10 gm × 15 cm, and indicates that an injury of 10 gm × 20 cm produces a “threshold” lesion suitable for the future evaluation of spinal cord treatment methods.


Author(s):  
Haojie Mao ◽  
Liying Zhang ◽  
King H. Yang ◽  
Albert I. King ◽  
J’ozsef Pál ◽  
...  

Biomechanical responses of a rat brain in a new weight-drop model were investigated by comparing histological results against finite element model predictions. This graded axonal injury rat model differed from others because of its utilization of intact skull without global angular motion to confound data analyses. Results demonstrated that the maximum principal strain and the compressive strain along the impact direction best correlated the experimentally observed injury locations while the shear strain did not have positive correlation.


2009 ◽  
Vol 4 (9) ◽  
pp. 1328-1337 ◽  
Author(s):  
Michael A Flierl ◽  
Philip F Stahel ◽  
Kathryn M Beauchamp ◽  
Steven J Morgan ◽  
Wade R Smith ◽  
...  

2002 ◽  
Vol 7 (4) ◽  
pp. 8-10
Author(s):  
Christopher R. Brigham ◽  
Leon H. Ensalada

Abstract Recurrent radiculopathy is evaluated by a different approach in the AMA Guides to the Evaluation of Permanent Impairment (AMA Guides), Fifth Edition, compared to that in the Fourth Edition. The AMA Guides, Fifth Edition, specifies several occasions on which the range-of-motion (ROM), not the Diagnosis-related estimates (DRE) method, is used to rate spinal impairments. For example, the AMA Guides, Fifth Edition, clarifies that ROM is used only for radiculopathy caused by a recurrent injury, including when there is new (recurrent) disk herniation or a recurrent injury in the same spinal region. In the AMA Guides, Fourth Edition, radiculopathy was rated using the Injury Model, which is termed the DRE method in the Fifth Edition. Also, in the Fourth Edition, for the lumbar spine all radiculopathies resulted in the same impairment (10% whole person permanent impairment), based on that edition's philosophy that radiculopathy is not quantifiable and, once present, is permanent. A rating of recurrent radiculopathy suggests the presence of a previous impairment rating and may require apportionment, which is the process of allocating causation among two or more factors that caused or significantly contributed to an injury and resulting impairment. A case example shows the divergent results following evaluation using the Injury Model (Fourth Edition) and the ROM Method (Fifth Edition) and concludes that revisions to the latter for rating permanent impairments of the spine often will lead to different results compared to using the Fourth Edition.


1997 ◽  
Vol 2 (4) ◽  
pp. 1-3
Author(s):  
James B. Talmage

Abstract The AMA Guides to the Evaluation of Permanent Impairment, Fourth Edition, uses the Injury Model to rate impairment in people who have experienced back injuries. Injured individuals who have not required surgery can be rated using differentiators. Challenges arise when assessing patients whose injuries have been treated surgically before the patient is rated for impairment. This article discusses five of the most common situations: 1) What is the impairment rating for an individual who has had an injury resulting in sciatica and who has been treated surgically, either with chemonucleolysis or with discectomy? 2) What is the impairment rating for an individual who has a back strain and is operated on without reasonable indications? 3) What is the impairment rating of an individual with sciatica and a foot drop (major anterior tibialis weakness) from L5 root damage? 4) What is the rating for an individual who is injured, has true radiculopathy, undergoes a discectomy, and is rated as Category III but later has another injury and, ultimately, a second disc operation? 5) What is the impairment rating for an older individual who was asymptomatic until a minor strain-type injury but subsequently has neurogenic claudication with severe surgical spinal stenosis on MRI/myelography? [Continued in the September/October 1997 The Guides Newsletter]


2015 ◽  
Vol 53 (12) ◽  
Author(s):  
LS Spitzhorn ◽  
M Megges ◽  
C Kordes ◽  
I Sawitza ◽  
S Götze ◽  
...  

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