The term “Cobb Angle” is used worldwide to measure and quantify the magnitude of spinal deformities, especially in the case of scoliosis. The Cobb angle measurement is the “gold standard” of scoliosis evaluation endorsed by Scoliosis Research Society. It is used as the standard measurement to quantify and track the progression of scoliosis. Cobb angle was first described in 1948 by Dr. John R Cobb where he outlined how to measure the angle of the spinal curve. Hence, the term “Cobb Angle” came about, bearing his name.
The forward bending test
is usually use to screen for scoliosis before puberty. An X-ray will be performed on the patient if this test is positive and the Cobb angle measured.
How To Measure Cobb Angle?
What Is The Significance of Cobb Angle?
- Locate the most tilted vertebra at the top of the curve and draw a parallel line to the superior vertebral end plate. [Insert picture showing vertebral endplates].
- Locate the most tilted vertebra at the bottom of the curve and draw a parallel line to the inferior vertebral end plate.
- Erect intersecting perpendicular lines from the two parallel lines.
- The angle formed between the two parallel lines is Cobb angle. [Insert pic to show measurement of cobb angle]
The Cobb angle is a measure of the curvature of the spine in degress which helps the doctor to determine what type of treatment is necessary. A Cobb angle of 10 degree is regarded as a minimum angulation to define Scoliosis.
A scoliosis curve of 10 to 15 degrees normally do not require any treatment except for regular check-ups with the orthopaedic doctor until the patient has gone through puberty and finished growing as the curvature of the spine usually do not worsen after puberty.
If the scoliosis curve is 20 to 40 degrees, the orthopaedic doctor will generally prescribe a back brace to keep the spine from developing more of a curve. There are several types of braces out in the market, with some worn for 18 to 20 hours a day, others only at night time. Which type of brace the orthopaedic doctor will prescribe will depend on the patient's lifestyle, and the severity of the curve(s).
Is surgery required?
If the Cobb angle is 40 or 50 degrees or more, surgery may be required to correct the curve. The orthopaedic surgeon will perform a procedure known as spinal fusion to link or “fuse” the vertebrae together so that the spine can no longer continue to curve. Metal rods, screws, hooks and wires will be used to correct the curve and hold everything in line until the bones heal. Teens who have had surgery to correct their scoliosis will usually return to school about a month after surgery, and should be able to gradually return to all normal activities after 6 to 12 months post surgery.