Spinal stenosis is the term used for the narrowing of one or sometimes even more parts of the spine. Such narrowing predominantly affects the cervical and lumbar spine. The condition results in compression and irritation of the spinal cord and/or spinal nerves which subsequently leads to a whole range of different neurological problems including numbness, pain, muscle weakness and incoordination of the affected extremities.
Spinal Stenosis in Middle Age
This medical issues is typical for older patients i.e. is commonly age-related. Namely, the spine succumbs specific changes as we get older. These generally affect the bones of the spinal column and protrude into the spinal canal making the inner volume reduced which triggers the above mentioned health problems.
Except for cervical spine, lumbar portion is mostly affected by age-related changes in elderly population. For instance, bony and soft tissues structures of the lumbar spine might become hypertrophic and precipitate entrapment of the cauda equina roots. As a result one starts to feel incapacitating and excruciating pain in the back which tends to radiate towards the lower extremities. Muscles become weak, there are leg paresthesias while more complex cases are characterized by loss over bower and bladder function.
Osteoarthritis, disc degeneration and thickened ligaments are three most common causes of spinal stenosis in older individuals. Osteoarthritis generally affects the facet joints. The repair of the damaged joints is in the form of new bony growths called bone spurs. They protrude into the spinal canal and trigger stenosis. In case of disc degeneration the disc per se may easily bulge or its jelly-like center protrudes into the spinal canal. This leads to compression or irritation of the content of the spinal canal. And finally, once the ligaments holding the vertebrae together become thick enough they may narrow the spinal canal compressing the nervous tissues inside.
Apart from the above mentioned spinal stenosis may also affect middle age people as well as young individuals in case they are suffering from certain medical conditions or have had some kind of injury to the spine. This is reported in patients with Paget's disease of the bone, those suffering from achondroplasia, people with spinal tumors and spinal injuries such as fractures or dislocation of one/more vertebrae.
As for treatment, it basically starts with medications like antidepressants, anti-seizures drugs or opioids all of which are prescribed to people who experience excruciating pain. Patients additionally benefit from physical therapy and may receive steroid injections. Surgery is indicated only if other treatments fail to bring the symptoms under control, patients develop severe neurological deficits that do not resolve on conservative treatment and in those suffering from spinal tumors.
MRI for Spinal Stenosis Diagnosis
Diagnosing spinal stenosis goes through several stages. Initially, all patients are asked specific questions regarding symptoms they experience and then undergo physical and neurological exams. Radiographic confirmation of the condition is achieved with several imaging modalities. Depending on the underlying cause of spinal stenosis sometimes X-ray may be sufficient enough while in more complex cases doctors additionally indicate CT scans or MRI of the spine.
Plain films of the spine are efficient when it comes to confirmation of degenerative changes affecting bony tissue in the area. They are, on the other hand, practically useless when there are structural changes in the soft tissues. In such case CT can or MRI must be done.
Even though CT scans can perfectly visualize the subarachnoid space and spinal roots this is an invasive test which carries certain risks. For that reason doctors prefer using MRI. Magnetic resonance imaging is a powerful tool for visualization of soft tissues. It gives an excellent insight in various structures of the spinal area including the entire spinal cord along with the cauda equina (the terminal part of the spinal cord), ligaments, epidural fat, subarachnoid space and spinal discs. Typical characteristics of spinal stenosis are loss of epidural fat and cerebrospinal fluid. They both can be easily confirmed with MRI.
The procedure is done in the axial and sagittal planes. A well experienced radiologist can easily notice potential underlying diseases that have triggered spinal stenosis. He/she will confirm the presence of osteophytes, calcified bulging discs, changes in epidural soft tissues etc. Enhancement of the obtained images is achieved with intravenously administered gadolinium, a highly efficient contract agent indicated only in healthy patients i.e. those who are not suffering from any kidney disorder.
If we want to discuss the degree of confidence, scientists assure that MRI is practically the best diagnostic tool for spinal stenosis. So, most medical experts opt for this imaging technique as soon as they assume the person is suffering from spinal stenosis which cannot be properly evaluated with plain radiographs.
And finally, a false-positive finding is a rare occurrence. False-negative results may occur more frequently but they are mostly related to movement artifacts.
All in all, spinal stenosis is severe condition which in the long run may lead to permanent neurological sequelae. But if timely diagnosed, which can be perfectly achieved with MRI of the spine, and adequately treated patients may fully recover and suffer no permanent damage.