3 types:
1-Idiopathic: when you measures the anterior-posterior diameter of the spinal canal, it will be reduced.
-Normal dimension of the lumbar spinal canal is 1.3.cm.
-If it is less than 1.3 cm, you can called the condition lumbar spinal canal stenosis.
-Relative spinal canal stenosis is between 1.1-1.2 cm.
-While the absolute spinal canal stenosis is 1 cm or below.
2-Developmental type: Due hypertrophied laminae, articular facets and ligamenta flava(It is a ligament in which it appears as a hypo intense structure in all sequences, normally it is seen as a thread like black structure lie immediately adjacent to the laminae).
-All the above mentioned causes leading to narrowing of the spinal canal, and at the same time, if you measures the A-P diameter of the canal you may find it within normal limit.
-You may find both types of spinal canal stenosis at the same time.
3-Acquired type: Could be due disc lesion, osteophytes, ligamentous calcification.
-At that time, we use to measure both A-P diameter of the spinal canal and the diameter of the lateral spinal recess.
-In MRI examination, if we needs to evaluate the presence of spinal canal stenosis, we go to the sagital T2 image, if we find CSF surrounding the conus and the nerve roots from anterior and posterior, this considered normal, but if we find the conus and the nerve roots not surrounded by CSF, this will be considered a spinal canal stenosis.
-Also, if we find the spinal canal is bigger than normal, more than 2 cm., this condition known as capacious spinal canal (It causes pain for the patient as the small canal due to ectasia of the cecal sac which is not supported by the bony elements of the spinal canal).
Cervical canal stenosis:
-In MRI examination, if we needs to evaluate the presence of spinal canal stenosis, we go to the sagital T2 image, if we find CSF surrounding the spinal cord from anterior and posterior, this considered normal, but if we find the spinal cord not surrounded by CSF, this will be considered a spinal canal stenosis.
-Again, if the cervical spinal cord is surrounded from anterior and posterior by CSF, this will be considered normal.
But if the spinal cord is surrounded from one side only by CSF, this will be considered mild degree of cervical spinal canal stenosis.
And if the spinal cord is not surrounded from both sides by CSF but it is not compressed, this will be considered as moderate degree of spinal canal stenosis.
Finally, if the cord is not surrounded by CSF and at the same time is compressed (caliber of the cord at the site of stenosis is smaller than that of the cord above or below), this will be a severe degree of spinal canal stenosis.
-Always, examine by vision, the diameter of the spinal canal opposite the body of vertebra and not opposite the disc.
-Normal dimension of the lumbar spinal canal is 1.3.cm.
-If it is less than 1.3 cm, you can called the condition lumbar spinal canal stenosis.
-Relative spinal canal stenosis is between 1.1-1.2 cm.
-While the absolute spinal canal stenosis is 1 cm or below.
2-Developmental type: Due hypertrophied laminae, articular facets and ligamenta flava(It is a ligament in which it appears as a hypo intense structure in all sequences, normally it is seen as a thread like black structure lie immediately adjacent to the laminae).
-All the above mentioned causes leading to narrowing of the spinal canal, and at the same time, if you measures the A-P diameter of the canal you may find it within normal limit.
-You may find both types of spinal canal stenosis at the same time.
3-Acquired type: Could be due disc lesion, osteophytes, ligamentous calcification.
-At that time, we use to measure both A-P diameter of the spinal canal and the diameter of the lateral spinal recess.
-In MRI examination, if we needs to evaluate the presence of spinal canal stenosis, we go to the sagital T2 image, if we find CSF surrounding the conus and the nerve roots from anterior and posterior, this considered normal, but if we find the conus and the nerve roots not surrounded by CSF, this will be considered a spinal canal stenosis.
-Also, if we find the spinal canal is bigger than normal, more than 2 cm., this condition known as capacious spinal canal (It causes pain for the patient as the small canal due to ectasia of the cecal sac which is not supported by the bony elements of the spinal canal).
Cervical canal stenosis:
-In MRI examination, if we needs to evaluate the presence of spinal canal stenosis, we go to the sagital T2 image, if we find CSF surrounding the spinal cord from anterior and posterior, this considered normal, but if we find the spinal cord not surrounded by CSF, this will be considered a spinal canal stenosis.
-Again, if the cervical spinal cord is surrounded from anterior and posterior by CSF, this will be considered normal.
But if the spinal cord is surrounded from one side only by CSF, this will be considered mild degree of cervical spinal canal stenosis.
And if the spinal cord is not surrounded from both sides by CSF but it is not compressed, this will be considered as moderate degree of spinal canal stenosis.
Finally, if the cord is not surrounded by CSF and at the same time is compressed (caliber of the cord at the site of stenosis is smaller than that of the cord above or below), this will be a severe degree of spinal canal stenosis.
-Always, examine by vision, the diameter of the spinal canal opposite the body of vertebra and not opposite the disc.
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