Spinal canal stenosis refers to the narrowing (stenosis) of the spinal canal. The canal is surrounded by bone and ligaments that protect the soft spinal cord. When the canal narrows, this exerts pressure on the central nervous system and all the nerves that run within it, which is very painful. In addition to severe pain and disruption of fine motor skills, this also leads to sensory disturbances in the legs and thus to major limitations in terms of walking. Spinal canal stenosis mostly affects older people and is a typical degenerative disease.
The symptoms differ depending on where the narrowing of the spinal canal occurs. If the lumbar region is affected, the pressure on the nerves causes back pain that radiates to the hips and legs. If there is constriction in the cervical spine, the pain radiates to the shoulders and arms.
Depending on which nerves are affected, the patient may also experience numbness, as problems with their reflexes and restricted mobility.
The symptoms of lumbar spinal stenosis include pain in one or both legs after walking a certain distance or standing for a period of time. Leg pain is usually accompanied by back pain. The pain always occurs when the individual adopts a ‘stretched’ position with a straight spine. Bending the body or changing the position of the body so that the back is more arched provides some relief. This form of spinal stenosis affects about 30% of all patients. Stenosis of the spinal cord is also very common in the cervical spine.
Spinal stenosis can be congenital or may develop as part of the ageing process. In congenital spinal stenosis, the pieces of bone that connect the vertebral joint and the vertebral body (the pedicles) throughout the spine are too short. Acquired spinal stenosis can affect the cervical and lumbar spine. It may have degenerative causes, such as wear and tear of the intervertebral discs. Over time, the intervertebral discs shorten, which reduces the distance between the vertebral bodies. As a result, the vertebral arch ligaments are no longer taut. The slackened ligaments then constrict the spinal canal. The mobility of the affected vertebrae also increases, which exerts additional pressure on the joints. This results in bony ‘build-ups’ that narrow the canal even further. Acquired spinal canal stenosis is common in people over the age of 60.
Since the symptoms of spinal stenosis are very varied, it is essential to rule out the possibility of other conditions during diagnosis. The doctor will carry out a physical examination in which they attempt to simulate the pain described by moving the body, back, and neck in ways that reproduce the pain. This is followed by special X-rays and MRI scans. These scans provide an accurate overview of the spine and the areas affected by stenosis.
The symptoms of mild spinal stenosis are often tolerable for the patient. Treatment does not necessarily have to be started immediately; it may be sufficient to simply monitor the progression. If the patient is suffering, a specific course of treatment is started, which may be conservative or surgical.
At the beginning of the treatment, the aim is to relieve the symptoms. This is usually done with the help of painkillers and antispasmodics. Physiotherapy is used to help strengthen the back muscles. If the stenosis is due to arthritis of the vertebral joint, building muscle can also help to slow down the progression of the arthritis. There are also various exercises you can do at home, which can be prescribed for you by your doctor, nurse or physiotherapist. These aim to build up and strengthen the back muscles in order to stabilise the back and thus reduce the pressure on the vertebrae.
As an additional measure, epidural infiltration (e.g. sacral nerve block) may also be considered. With the sacral nerve block, a combination of cortisone and local anaesthetic is injected into the spinal canal under X-ray control. This usually provides relief for several months and can be repeated if necessary.
Surgical treatment is considered when the spinal stenosis is severely limiting the individual’s life and ability to work. This usually manifests itself in gait disorders with rapid fatigue when walking, shortened walking distances, signs of paralysis, as well as functional disorders and numbness in the extremities. The aim of the surgery is to reduce the pressure on the nerves. One reason for immediate surgery is if cervical spondylotic myelopathy is detected. This is the subsequent stage of a pronounced spinal stenosis and causes neurological impairments.
The method used mostly frequently in these circumstances is a procedure known as microsurgical decompression. It is usually possible to make it minimally invasive. An incision is made in the skin, under general anaesthesia, at the level of the constriction. The bone and soft tissue compressing the nerve tracts is then removed. This reduces the pressure and usually results in a quick recovery. If the disease is in its latter stages and thus the spinal cord has already been too severely damaged, it is possible that the symptoms will not completely subside.
If the cause of the spinal stenosis is diagnosed as hypermobility, microsurgical decompression is not usually a sufficient treatment method on its own. In this case, the affected spinal segment is stabilised using screw/rod systems in addition to the decompression.
After microsurgical decompression, rehabilitation is always required, which primarily comprises a specialised course of physiotherapy. In cases where signs of paralysis have resulted in gait disturbances or other neurological problems, neurological rehabilitation will be required, including gait training.
This is very specific to the individual and depends on where exactly the constriction is located. In the case of a stenosis in the cervical spine, the pain radiates to the upper extremities (arms). In the case of a stenosis in the lumbar spine, it is the lower extremities, i.e. the legs, that are affected.
If the symptoms have not improved by three months after the conservative treatment, or if the pain becomes so severe that day-to-day life and professional activities are extremely difficult, surgery may be required to provide relief. If paralysis and neurological problems arise, immediate surgery is crucial.