Cobb angle

Cobb angle measurement of a levoscoliosis

The Cobb angle, named after the American orthopedic surgeon John Robert Cobb (*1903-1967), was originally used to measure coronal plane deformity on antero-posterior plain radiographs in the classification of scoliosis^[1]. It has subsequently been adapted to classify sagittal plane deformity, especially in the setting of traumatic thoracolumbar spine fractures.

In the setting of spine trauma and assessing sagittal plane deformity, the Cobb angle is defined as the angle formed between a line drawn parallel to the superior endplate of one vertebra above the fracture and a line drawn parallel to the inferior endplate of the vertebra one level below the fracture.

The Cobb angle is the preferred method of measuring post-traumatic kyphosis in a recent meta-analysis of traumatic spine fracture classifications^[2]

There is much criticism of the Cobb angle for scoliosis diagnosis and even more criticism of the current surgical treatment of scoliosis. "The “prognostic” or “predictive” value of Cobb angle in curve progression is only slightly better than the odds of flipping a coin and ALL of the Cobb angle prognostic assumptions are based off a single study by Lonstein and Carlson in 1984, which has never been repeated or re-produced to this very day", according to Stitzel. ^[3]

Additional concerns regarding post diagnosis protocols for scoliosis include dangers of surgical intervention and poor outcomes.^[4]

Footnotes

1. ^ Cobb JR. The American Academy of Orthopedic Surgeons Instructional Course Lectures. Vol. 5. Ann Arbor, MI: Edwards; 1948.
2. ^ Keynan O, Fisher CG, Vaccaro A, Fehlings MG, Oner FC, Dietz J, Kwon B, Rampersaud R, Bono C, France J, Dvorak M. Radiographic Measurement Parameters in Thoracolumbar Fractures: A Systematic Review and Consensus Statement of the Spine Trauma Study Group. Spine. Volume 31(5), 1 March 2006, pp E156-E165
3. ^ Is Cobb angle an obstacle to the future progress in scoliosis treatment?. FixScoliosis.com. Retrieved on 2011-06-03.
4. ^ Dangers of Scoliosis Surgery. scoliosiscorrectioncenter.com. Retrieved on 2011-06-03.