Stenosis of the spinal canal, osteophytes of the spine - Causes, symptoms and treatment. MF.
Spinal stenosis is a chronic process characterized by abnormal narrowing of the central spinal canal, lateral pocket or intervertebral foramen with bony, cartilaginous and soft tissue structures, invading them into spaces occupied by nerve roots and spinal cord. Narrowing of the spinal canal, caused by disc hernias, which lead to acute compression of the neurovascular structures to stenosis usually does not apply.
Spinal stenosis is a disease involving a combination of a narrowing of the vertebral canal according to either computed tomography( CT), or magnetic resonance imaging( MRI) or spinal radiography( spondylography) and characteristic clinical symptoms. When MRI is performed, people over 60 years of age are noted that 21% of them had X-ray signs of narrowing of the spinal canal at the lumbar level. Only one third( 33%) presented stinging complaints
Classification of stenoses of the spinal canal
According to anatomical criteria,
- is distinguished for central stenosis
- a decrease in the distance from the posterior surface of the vertebral body to the nearest opposite point on the arch at the base of the spinous process( up to 12 mm -relative stenosis, 10 mm or less - absolute) or the area of the vertebral canal( up to 100 mm² - relative stenosis, 75 mm² or less - absolute stenosis)- lateral stenoses - narrowingradicular canal and intervertebral foramen up to 4 mm or less
The etiology distinguishes
- congenital or idiopathic stenosis;achondroplasia
- acquired stenosis
- combined stenosis - any combination of congenital and acquired stenosis
Causes of stenosis of the spinal canal
The vertebral canal is formed by arches and vertebral bodies, as well as tight ligaments that connect the vertebrae to each other. Between the spinal cord and the walls of the spinal canal is a space filled with loose fatty tissue and cerebrospinal fluid. The presence of this space allows the body to compensate for an insignificant narrowing of the spinal canal without the development of neurological complications. However, progressive stenosis of the spinal canal inevitably leads to compression of the spinal cord and( or) nerve roots, which is accompanied by the appearance of neurological symptoms.
Stenosis of the spinal canal is most often noted at the lumbar level. Narrowing of the lumen of the spinal canal can be caused by the development of a herniated disc, tumor, traumatic injury, yellow ligament thickening, facet joint arthrosis, osteophyte growth, disc protrusion, spondylolisthesis and some other reasons.
Congenital stenosis is caused by the anatomical features of the spine in a person and manifests:
- shortening the arc of the vertebrae
- achondroplasia( increasing the thickness of the vertebrae, shortening the leg and reducing the height of the vertebral body)
- cartilaginous and fibrotic diastematomyelia
In this case, the symptoms of spinal stenosis appearat a younger age.
The causes of the acquired stenosis are different. The main ones are:
- deforming spondylarthrosis with hypertrophy of intervertebral joints, formation of marginal osteophytes
- ossified hernia of intervertebral discs
- hypertrophy and ossification of yellow ligament
- Forester disease( diffuse idiopathic hyperostosis of rheumatoid nature)
- Bechterew's disease
- spondylolisthesis of degenerative-dystrophic genesis
- iatrogenic stenosis - formation of subarachnoid adhesions and / or postoperative scars
- "steel stenosis" - implantationmetal structures in the lumen of the vertebral or radicular canal
Central stenosis arises due to pathological processes in the anatomical structures forming the vertebral canal( in particular, intervertebral discs, intervertebral joints, yellow ligament, posterior longitudinal ligament), which contains a spinal bag with nerves included in itroots.
Lateral stenosis can occur in one or more of the three anatomical zones: the entry zone( lateral recess), the middle zone and the exit zone( intervertebral foramen).
Lateral recession is limited:
- posterior - superior articular process of the vertebra
- medially - dura bag
- laterally - pedicle of the vertebra
- caudal - vertebral body
- rostral - intervertebral disc
Normally the height of the lateral recession is 5 mm. Reducing its size to 3-4 mm is defined as stenosis. In most cases, the stenosis of the lateral recess is caused either by hypertrophy of the superior articular process of the vertebra or by the posterolateral hernia of the intervertebral disc.
The middle zone is limited:
- at the back - the intervertebral joint
- from above - the vertebra peduncle
- in front - the vertebral body
- medially - by the vertebral canal.
Narrowing of the middle zone and, correspondingly, compression of the spine can occur with spondylolisthesis and rotational deformations.
Intervertebral foramen is limited to
- from above and from below - legs of adjacent vertebrae of
- in front - by the bodies of adjacent vertebrae and intervertebral disc
located between them - behind - intervertebral joint and lateral part of yellow ligament
Normally the height of the intervertebral foramen is 20-30 mm, width8-10 mm, the area is from 40 to 160 mm².Decrease in the height of the intervertebral foramen less than 15 mm is interpreted as its stenosis( in conjunction with the clinical signs of lesion of the nerve root)
Stenosis of the intervertebral foramen is more common in the lower lumbar region, when there is stenosis of the spinal canal in the cervical or thoracic spine.
Pathogenesis of spinal stenosis
The pathophysiological mechanisms that cause the development of characteristic complaints are due to a combination of three groups of factors - increased epidural pressure, aseptic inflammation and ischemia.
The occurrence of each of them is caused by chronic compression of the neurovascular structures of the spinal canal.
Due to chronic compression there is a mismatch of blood flow to the neural structures of the spinal canal. The level of incoming blood decreases and accordingly there is ischaemia of the nerve root( with lateral stenosis) and the cauda equina( cauda equina)( in the central).With combined stenosis, there is a combination of ischemia of both the cauda equina and the nerve root. It is noted that the phenomena of ischemia cause the processes of demyedinization, the formation of adhesions between the soft and arachnoid cerebral membranes, the development of interstitial fibrosis and cicatricial-adhesive epidurit. The need for oxygen increases with the strengthening of biochemical processes. This explains the fact that complaints of pain in the back and / or legs, weakness in the stenosis of the spinal canal occur when walking.
The mismatch in the volume of the neurovascular structures to the volume of the spinal canal causes an increase in the epidural pressure and, as a consequence, causes the onset of the inflammatory process. Epidural pressure rises when walking, which causes the production of ectopic nerve impulses and is manifested by the onset of pain sensations.
A feature of the pathogenesis of the spinal canal is the dependence of its volume on the position of the body. When a person squats, the lumbar lordis straightens or kyfosiruetsya, articular processes diverge, increases the lumen of the intervertebral opening, releasing the squeezed blood vessels, which leads to the restoration of normal blood flow, and hence nutrition of ischemic neural elements. When bending, the height of the intervertebral foramen is increased by 12%, while the extension is reduced by 15%.This explains the characteristic complaint, which consists in the regression of pain until complete disappearance when sitting down, bending down. Moreover, on the basis of this symptom, a differential diagnosis is performed between the neurogenic( with stenosis of the spinal canal) and vascular intermittent claudication. So, with neurogenic intermittent claudication, unlike a vascular man, a person can work long enough on a stationary bike, do not experience complaints when driving a car for a long time.
Spinal stenosis as a consequence of osteochondrosis
The most commonly acquired stenosis of the spinal canal is the last 4th stage of osteochondrosis of the spine. Its appearance is characterized by the fact that against the backdrop of instability in the vertebral-motor segment( the third stage of osteochondrosis) compensatory processes are developing aimed at its stabilization. These include the proliferation of bone tissue in the form of osteophytes, arthrosis of the intervertebral joints. Intervertebral joints limit both the vertebral canal and the nerve root entry zones, the intermediate zone and the intervertebral foramen. Accordingly, the proliferation of intervertebral joints leads to a narrowing of the above anatomical formations and, accordingly, to the development of stenosis.
Symptoms of spinal stenosis
Narrowing of the spinal canal leads to compression and irritation of the nerve roots. This can cause pain and impairment of the nerves. With stenosis, the delivery of oxygen and nutrients to the spinal cord is reduced. During physical activity, such as walking or running, nerve cells in the spinal cord need increased delivery of oxygen and nutrients. However, with stenosis of the spinal canal this does not happen, since the volumetric blood flow velocity can not increase in proportion to the need of nerve cells due to increased interstitial pressure in the vertebral canal, which causes compression of the blood vessels. Ischemia of the spinal cord leads to pain and weakness in the limbs.
Most often with stenosis of the spinal canal, patients complain of pain, heaviness and weakness in the legs and lumbar region that occur when walking or standing for a long time. After rest, these symptoms tend to disappear. This sympathocomplex was called neurogenic intermittent claudication, by analogy with intermittent claudication in vascular diseases of the lower limbs.
In a study of a group of patients with spinal stenosis at the lumbar level, the leading complaints are:
- back and lower back pain - lumbargia( 95%)
- neurogenic intermittent claudication syndrome( 91%)
- radicular pain in one or two71%)
- Tension symptoms( Lassega, Wasserman, etc.) 75%
- weakness in one or two legs( 33%)
- Musculoskeletal sensation 63%
- Leg paresis 59%
- Ischialgiapain in the leg) 54%
- Hypotrophy of lower limb muscles 43%
- NARSensitivity in the anogenital zone 21%
- Crimpi of the calf muscles 20%
- Pelvic function disorder 14%
In patients who noted a combination of pain in the leg and lower back, 70% reported the same intensity of pain in the leg and lower back, 25%in the legs. In 58% of cases the pain was in one leg and in 42% it was bilateral. Most patients had radiculopathy of several nerve roots. In general, pain in the stenosis of the spinal canal is spreading in L5( 91%) and SI( 63%) dermatomes, and less often in L1-L4 dermatomes( 28%).
Neurogenic intermittent claudication is a pathognomonic symptom of spinal canal stenosis, suggesting the presence of spinal canal stenosis before additional survey methods are performed. It is characterized by the appearance of pain when walking, which regresses when sitting down or torso bending forward. After this, a person can again go through a certain distance before the appearance of painful sensations. In the sitting position, the patient can perform any work( an exercise bike, driving a car) without pain. The intensity of neurogenic intermittent claudication is estimated at a distance( meters) that a person can pass before the onset of pain.
Diagnosis of spinal stenosis
Diagnosis of spinal stenosis can be established based on a combination of clinical complaints and narrowing of the lumen of the spinal canal, according to additional research methods.
Narrowing of the spinal canal( anteroposterior size less than 12 mm) can be detected according to magnetic resonance imaging, computed tomography and radiography( spondylography) of the lumbosacral spine.
Radiography is a painless research method that allows visualizing bone formations with X-rays. With stenosis of the spinal canal due to degenerative changes, such symptoms as a decrease in the height of the intervertebral fissure, osteophytes, facet joint hypertrophy, and instability of the vertebral-motor segment during functional tests( flexion and extension) can be detected during an X-ray examination. X-rayography also reveals vertebral fractures, vertebral tumors, and some infectious lesions of the spine. However, with this method of research soft tissue is not visualized, therefore magnetic resonance imaging is necessary for an accurate diagnosis.
Magnetic resonance imaging is a painless, absolutely safe method of investigation based on the use of radio waves to obtain an image of the internal structure of the body. With MRI, the image is represented as a series of longitudinal and transverse sections. With this method of investigation, any pathological changes in soft tissues, including the spinal cord and nerves, are easily diagnosed. MRI can also reveal degenerative changes in the intervertebral discs, hypertrophy of the facet joints, stenosis of the spinal canal, disk hernia.
With computed tomography, the examination is carried out using X-rays, and the information data is processed using a computer. Images are obtained as a series of slices, as well as for MRI.This study is optimal for identifying such conditions as hypertrophy of the facet joints, bone spurs, degenerative changes in bone tissue. To facilitate the visualization of soft tissue, computed tomography is often combined with a myelogram.
Treatment of spinal stenosis
Treatment of spinal stenosis can be conservative and operative.
Conservative treatment of spinal stenosis
Conservative treatment includes the appointment of antalgic, vascular, anti-inflammatory drugs. With moderate symptoms of spinal stenosis, effective conservative treatment, which includes medical therapy, physiotherapy, massage, as well as epidural steroids. The latter method consists in the introduction of solutions of glucocorticoid hormones( kenalog, diprospan) into the epidural space in the area of stenosis of the spinal canal. The effect of glucocorticoids is based on the reduction of pain syndrome due to the reduction of inflammation and local edema in the area of compression of nerve structures. Often, glucocorticoid hormones are used in combination with local anesthetics, which quickly relieve pain, but act briefly. On the contrary, the effect of glucocorticoid hormones develops slowly enough, and the duration of action is 2-4 weeks. Epidural introduction of steroids is effective only in 50% of patients. At the same time complications can occur with this method of treatment, therefore it is used only when other methods of conservative therapy are ineffective.
Conservative treatment of spinal stenosis is not effective in the treatment of spinal stenosis, as it leads to an improvement in well-being only in 32-45% of patients.
Surgical treatment of spinal stenosis
Surgical treatment of spinal stenosis has a number of characteristics.
Firstly, there are several types of operations used for stenosis.
These include:
- decompression laminectomy
- stabilizing system installation
- installation of interstitial fixation systems
Secondly, spinal stenosis is often combined with other types of spinal pathology, such as instability and herniated intervertebral discs.
Decompressive laminectomy
Decompressive laminectomy involves resection of structures that lead to the compression of the nerve root and / or the cauda equina( cauda equina) with posterior access, namely the spinous process.arches of vertebrae, yellow ligament, intervertebral joints.
Historically, decompressive laminectomy was the first type of surgery used to treat spinal stenosis.
At the same time, carrying out decompressive laminectomy has a number of shortcomings that lead to its insufficient effectiveness. So, due to this operation, there is a removal of those structures that form the third support column of the spine according to Denis or the second pillar of the clavus by Holdsworth. The result in a large number of cases is the development of instability of the spine, which leads to unsatisfactory results of treatment, a syndrome of unsuccessfully operated spine. Various sources indicate a 13-43% risk of developing instability after a decompressive laminectomy. Thus, after analyzing his clinical material accumulated for 27 years, the pioneer of the study of stenosis of the vertebral canal, Henk Verbist, noted that the number of excellent and good results after a decompressive laminectomy is 68%.In another study, 119 patients with spinal canal stenosis operated by the method of decompressive laminectomy and an average catamnesis of 4.6 years were surveyed.37% of patients assessed their condition after the operation as "significantly better", 29% - "somewhat better", 17% - "no change", 5% - "somewhat worse", 12% - "significantly worse".It was also noted that the number of unsatisfactory results increases with time. Insufficient effectiveness of decompressive laminectomy, due to the development of instability of the spine, led to its addition in many cases, stabilizing operations.
Stabilizing operations for stenosis of the spinal canal
Supporters of spine fixation after laminectomy refer to biomechanical data. It was found that laminectomy leads to an increase in the volume of motion with flexion by 16%( P & lt; 0.05), an extension of 14%( P & lt; 0.04) of axial rotation by 23%( P & lt; 0.03).With flexion, the tension of the fibrous ring of the disc after interlaminar decompression is increased by 20%, and after laminectomy by 130%.
The addition of decompressive laminectomy by stabilization systems( front or rear) significantly improved the results of surgical treatment of spinal stenosis.
At the same time, the use of stabilizing systems is not without flaws. In addition to possible complications, during their installation, there are violations of the biomechanics adjacent to the stabilized vertebral-motor segments, which are manifested by their hypermobility [26].This in turn leads to development, the so-called "disease of an adjacent level".It includes the development of spondylolisthesis, stenosis of the spinal canal, fractures, scoliosis.
Insufficient effectiveness of decompressive laminectomy due to the development of spinal instability, the development of "adjacent level disease" with the addition of decompression by the installation of stabilizing systems led to the search for alternative methods of surgical treatment of spinal stenosis.
Intermittent fixation systems
The concept of dynamic dynamic stabilization is based on the fact that the trigger mechanism of spinal stenosis is a decrease in the height of the intervertebral disc due to degenerative changes, which in turn causes a redistribution of the axial load from the front pillars( according to Denis) to the rear( up to 70%).The use of dynamic interstitial fixation reduces the load on the posterior supporting columns and widens the area of the vertebral canal, which contributes to the reduction or disappearance of the lumbar syndrome caused by facet syndrome.
The technique for installing inter-active dynamic fixation systems is to perform a back decompression( Cophlex system, DIAM, WALLIS), followed by insertion into the interstitial gap of the implants, which on the one hand restore the back column( according to Denis) of the spine, and on the other,extension in both operatively and in adjacent vertebral-motor segments.
The effectiveness of surgical interventions for spinal stenosis, in which the microsurgical decompression and dynamic interstitial stabilization are combined, is 87%, they allow to significantly reduce the recovery period.
The peculiarity of the systems of interstitial dynamic fixation is the possibility of carrying out both flexion and extension in the spinal-motor segment, which prevents the development of "disease of adjacent levels" in patients.
When implants are installed in the interstitial space, the load on the intervertebral joints also decreases, axial decompression of the rootlets occurs due to an increase in the height of the intervertebral foramen. Reducing the load on the joints contributes to the relaxation of the ligament apparatus.
Contraindication to the use of interstitial dynamic stabilization is instability in the vertebral-motor segment. Since they stabilize only the rear pillars( according to Denis), their therapeutic effect for this pathology is insufficient.
Currently, the following intermittent dynamic fixation systems are used in medicine - Coflex( Co-promotes flexion) - a synonym for U-implant, DIAM( Device for Intervertebral Assisted Motion), Wallis( Wall Inter Spinously placed), X-Stop( eXtension Stop), In-Space and Aperius.
Features of surgical treatment of stenosis combined with instability
With the combination of spinal stenosis with spinal instability, the use of only decompression or interstitial dynamic fixation systems is unacceptable, as it will cause instability and worsening of the patient's well-being.
With instability in combination with stenosis of the spinal canal, the method of choice is the use of stabilizing systems( both front and rear)
Features of surgical treatment of spinal stenosis in combination with intervertebral hernia
Narrowing of the spinal canal results in the appearance of even a small protrusionintervertebral disc translating the state of subcompensation in decompensation. A sharp increase in clinical manifestations caused by herniated intervertebral discs indicates a combination of it with a narrowing of the spinal canal.
This combination requires microdiscectomy, a feature of which is a wide resection of bone structures( intervertebral joint, vertebra arches) causing a narrowing of the spinal canal.
During rehabilitation, physiotherapy and reflexotherapy are used.