Lumbar spinal stenosis refers to the abnormal structure of the spinal canal due to primary or secondary factors, narrowing of the spinal canal lumen, and the appearance of low back pain mainly characterized by intermittent claudication.
Classification: According to the international classification, it is divided into the following categories.
1, stenosis due to spinal degeneration: thickening of the vertebral plate and hyperplasia of the vertebral body due to age-related changes in the spine and strain, etc., resulting in volumetric narrowing of the spinal canal, hypertrophy of the small joints, and hypertrophy of the ligamentum flavum, etc.
2.Stenosis due to compound factors: stenosis due to congenital-acquired deformity, stenosis due to disc herniation that reduces the volume of the spinal canal, or stenosis due to a compound of disc herniation and mild stenosis of the spinal canal.
3, stenosis due to spondylolisthesis (degenerative) and osteolysis disease.
4, medically induced stenosis: there is postoperative osteophytosis with scar proliferation adhesions caused by myelin injection, etc.
5. Injurious stenosis: such as compression fractures and fracture dislocations.
6.Other: deformational osteitis (Pagets disease) has spinal deformation and the spinal canal can be narrowed; fluorosis can also cause hyperplastic deformation and cause stenosis.
Etiology
From the perspective of modern medicine, the common causes of lumbar spinal stenosis are as follows.
1, developmental lumbar spinal stenosis: this spinal stenosis is caused by congenital developmental abnormalities.
2. degenerative lumbar spinal stenosis: it is mainly caused by degenerative lesions of the spine.
3, spinal slippage lumbar spinal stenosis: when spinal slippage occurs due to discontinuity or degeneration of the lumbar isthmus, the spinal canal is further narrowed due to anterior and posterior displacement of the upper and lower spinal canal, while spinal slippage, which can promote degenerative changes, aggravates spinal stenosis
4, traumatic spinal stenosis: spinal stenosis is often caused by trauma to the spine, especially when the spine is fractured or dislocated due to severe trauma.
5, medical spinal stenosis: in addition to surgical errors, mostly due to spinal fusion caused by the interspinous ligament and ligamentum flavum hypertrophy or implantation of the vertebral plate thickening, especially after the posterior decompression of the vertebral plate and then localized in the implantation of fusion, the result of the narrowing of the spinal canal compression of the cauda equina or nerve root, causing lumbar spinal stenosis.
6, various inflammatory diseases in the lumbar spine: including specific or non-specific inflammation, new organisms in the spinal canal or on the canal wall can cause spinal stenosis. Various deformities such as age-related hunchback, scoliosis, ankylosing spondylitis, fluorosis, Paget’s disease and vertebral joint loosening can cause spinal stenosis.
Symptoms: The disease occurs in middle-aged men over 40 years of age and starts slowly. The main clinical manifestations are low back and leg pain and intermittent claudication, which can appear after trauma or aggravate the symptoms.
1.Lumbar and leg pain
Most patients with developmental lumbar spinal stenosis have low back pain and pain in the groin and femur, while almost all patients with secondary lumbar spinal stenosis have recurrent lower sleep pain, often accompanied by unilateral or bilateral radiating pain and abnormal sensation in the lateral and posterior thigh cavity. The symptoms often increase when walking or standing, and decrease or disappear when squatting or lying down.
2.Lower back pain
This is because when the lumbar spine is hyperextended, the anterior part of the intervertebral space is widened and the posterior part is narrowed, so that the intervertebral disc and the fibrous ring protrude into the vertebral canal cavity, while the ligamentum flavum also thickens with relaxation and forms folds, so that the intervertebral foramen is narrowed and the volume of the vertebral canal is further reduced and narrowed, which compresses or stimulates the nerve root and cauda equina nerve and pain occurs.
3.Intermittent claudication
Intermittent claudication is another major symptom of lumbar spinal stenosis, mostly seen in patients with central spinal stenosis or severe disease. Intermittent claudication has been observed in 98 out of 105 cases of lumbar spinal stenosis, and it is common in lumbar spinal stenosis with multiple vertebral segments.
It is progressive in nature. The specific manifestation is that after walking about one or two hundred meters, or standing for about several minutes or more than ten minutes, the patient feels pain, numbness, soreness and weakness in one or both calves and feet, so that he cannot continue walking and must squat or bend over for a moment before walking again. But soon after walking and pain, this phenomenon of walking and stopping is intermittent claudication. The diagnosis of this disease is of great significance.
Some people have divided the intermittent claudication of this disease into two categories: positional claudication and ischemic claudication.
4, positional claudication
It accounts for the majority. Intermittent claudication occurs after walking or standing for a long time. The symptoms are relieved after squatting or bending down, so these patients often walk bending down. In addition, stretching, supine and prone can aggravate the pain, and side lying and knee flexion can relieve the pain. This kind of intermittent claudication is mainly due to the compression of the cauda equina nerve by the yellow ligament bulging into the vertebral canal cavity.
5, ischemic claudication
It is a minority. Muscle spasmodic pain occurs after walking or moving the lower limbs, and the pain disappears after stopping the activity. This spasmodic pain mostly occurs in the lateral muscle group when the calf.
In conclusion, most scholars believe that the reason for intermittent claudication in lumbar spinal stenosis is that standing or walking activities increase the need for blood supply to the nerve roots, and the increase in lumbar lordosis often further narrows the spinal canal, reducing the blood supply and imaging the venous reflux, which eventually exacerbates the ischemic state of the nerve roots, so that neurogenic intermittent claudication occurs. It differs from vascular intermittent claudication in that the blood circulation around the lower extremity is always normal, the dorsalis pedis artery pulses well, and it is often accompanied by symptoms of hemorrhagic pain.
Clinical observation proves that the longer and more extensive the lumbar spinal stenosis, the more likely the symptom of intermittent claudication appears, and about 56% – 85% of patients with developmental lumbar spinal stenosis have intermittent claudication of both lower extremities. In contrast, patients with degenerative lumbar spinal stenosis often have unilateral intermittent claudication of the lower extremities. R. Porter observed that multisegmental central canal stenosis often leads to bilateral lower extremity intermittent claudication. In contrast, single-segment central canal stenosis or unilateral nerve root canal stenosis can only cause unilateral intermittent claudication of the lower extremities.
6. Urinary and fecal disorders
A small number of cases may be accompanied by urinary and fecal disorders.
7.Neurological signs
In lumbar spinal stenosis, the reduction of the spinal canal lumen occurs slowly and the nerve tissue can adapt to the narrowing changes gradually, so most patients have only minor signs. For example, toe flexor weakness, reduced or absent ankle reflex, reduced radicular distribution of pain in the lateral calf and foot of the lower extremity, and a few positive straight leg raise tests can be seen after the patient is made to walk briskly. In developmental lumbar spinal stenosis, most of the lumbar lordosis disappears, and a few of them have scoliosis, and there are no other abnormalities in spinal activities except posterior extension limitation.
8.Stenosis
It is mostly seen between lumbar spine 5 and sacral spine 1, and occasionally occurs between lumbar spine 4 and 5 and lumbar spine 3 and 4. Any abnormal change in each structure that makes up the nerve root canal, such as narrowing of the vertebral space, congenital hypertrophy of the synovial joint, thickening of the ligamentum flavum, etc., can cause nerve root canal stenosis. The clinical manifestation is mainly lower back pain, and about half of the patients have radiating pain or abnormal sensation in the buttocks on one or both sides. In a few patients, the pain in the lower leg is aggravated after walking, and the pressure pain in the lumbar region is obvious, and the straight leg raise test is positive.
Diagnostic points
The main symptoms of lumbar spinal stenosis are long-term recurrent lumbar and leg pain and intermittent claudication. The nature of the pain is soreness or burning pain, some of which may radiate to the outer thighs or front, etc., mostly bilaterally, and may alternate between the left and right legs. When standing and walking, lumbar and leg pain or numbness and weakness appear, pain and limp gradually worsen, even can not continue to walk, the symptoms improve after rest, riding a bicycle without hindrance. In severe cases, it may cause urinary urgency or difficulty in urination. Some patients may develop muscle atrophy of the lower limbs, with the most obvious being the tibialis anterior and extensor muscles, hyperalgesia, dull knee or Achilles tendon reflexes, and positive straight leg raise test. However, some patients have more complaints and do not have any positive signs.
Taking frontal, lateral and oblique X-ray of the lumbar spine can help in diagnosis, and changes such as narrowing of the intervertebral space, osteophytes, slipped vertebrae, increased lumbosacral angle and hypertrophy of small articular processes are often seen between lumbar 4 to 5 and lumbar 5 sacral 1. Intraspinal angiography, CT, and MRI can help clarify the diagnosis.
Treatment
Lumbar spinal stenosis is one of the conditions leading to chronic low back pain, and the treatment of this disease mainly includes conservative treatment and surgery.
The commonly used conservative treatments are
Medical sports
It can strengthen the muscular exercise of the back extensor and abdominal muscles to increase the stability of the lumbar spine, thus delaying the evolution of lumbar joint degeneration. Taijiquan has a good effect on the disease.
Surgical treatment
If the above conservative treatment is ineffective or the effect is not obvious, surgery can be considered.
Indications for surgery
1.Lumbar pain and paralysis of both lower extremities after activity, muscle atrophy, affecting life and work, which is not cured by conservative treatment.
2, Intermittent claudication aggravated, or standing time gradually shortened
3. Those who have obvious deficiency of nerve function.
The purpose of surgery is to relieve the compression of nerve tissue and blood vessels in the spinal canal, nerve root canal or intervertebral foramen. The common surgical procedures are laminectomy and nerve root decompression. Newer techniques include non-fusion techniques of the spine, such as interspinous bracing devices and arch nail elastic fixation devices.
Lumbar spinal canal stenosis of the lateral saphenous fossa
In some clinical cases, there is a preoperative diagnosis of lumbar disc herniation, but intraoperatively there is no herniated disc or only a small protrusion, and the main lesion is lateral stenosis of the spinal canal compressing the nerve roots.
Lateral saphenous fossa refers to the narrowing of the spinal canal extending laterally, mainly in the trilobar spinal canal and most typically in the lower two lumbar vertebrae. The lateral saphenous fossa is generally considered narrow if the anterior and posterior diameters are less than 3 mm, normal if they are more than 5 mm, and relatively narrow if they are in between.
So, why is the lateral saphenous fossa narrowed? Congenital factors can cause lateral saphenous stenosis. The deep lateral saphenous fossa and small anterior-posterior diameter of the trilobar spinal canal are developmentally predisposed to stenosis. Another important factor contributing to stenosis is degeneration. Degeneration of the intervertebral disc with calcification of the fibrous annulus, hyperplasia of the posterior superior border of the vertebral body, which protrudes from the anterior to the posterior into the lateral saphenous fossa; supra-articular synapse of the inferior vertebrae after disc stenosis; hyperplasia of the isthmus, hypertrophy and calcification of the ligamentum flavum, which protrudes from the posterior into the lateral saphenous fossa; and anterior or posterior slippage of the degenerated vertebral body can contribute to lateral saphenous fossa stenosis.
Manifestations of lumbar lateral saphenous stenosis
The disease occurs mostly in middle age and above, more in men than in women, which may be due to the fact that men are heavily burdened, the lower lumbar spinal canal is more clover-shaped, and the preserved space around the nerve roots is small and prone to compression symptoms.
Patients generally have a long history of low back pain and low back and leg pain, leg pain is often heavier than those with herniated discs, and exertion or trauma can induce pain or make symptoms significantly worse. Neurogenic intermittent claudication is progressive, and the claudication distance decreases from hundreds of steps to tens of steps, and is relieved after squatting or sitting down to rest. Lower extremity pain radiates along the lumbar or sacral innervation zone.
Lateral saphenous stenosis is a mechanical compression of the nerve root by adjacent structures and is not amenable to conservative treatment. Traction is only suitable for those with less severe compression. For diagnosed cases, surgical treatment should be chosen to completely relieve the nerve root compression, and the surgical technique should be improved to avoid unnecessary expansion of decompression, which may affect the stability of the spinal intersegments.
Lumbar disc herniation and lumbar spinal stenosis
Lumbar spinal stenosis refers to any form of narrowing of the spinal canal, nerve root canal, intervertebral foramen, etc. caused by various factors such as congenital development or acquired degeneration of the bony or soft tissues that make up the spinal canal, resulting in compression or irritation of the cauda equina or nerve roots and a series of clinical manifestations of the syndrome. The clinical manifestations of lumbar spinal stenosis are
1. Intermittent claudication: When the patient stands upright or walks, different sensations such as pain, numbness, heaviness, and weakness occur in the lower extremities that gradually increase, so that they have to change their posture or stop walking, and the symptoms can be alleviated or disappear after squatting or resting for a moment, and continue to stand or walk, and the symptoms reappear and are forced to rest again. Because of repeated walking and resting, the walking distance is gradually shortened. Intermittent claudication may not occur when climbing mountains or riding bicycles.
2. Lower back pain: Most patients with lumbar spinal stenosis have a history of lower back pain or are accompanied by lower back pain. The pain is generally mild and is relieved or disappears when resting in bed, and the lumbar forward flexion is not restricted, but the posterior extension is often limited.
3. Nerve root compression symptoms and signs: Nerve root canal stenosis causes corresponding symptoms and signs of nerve root compression or irritation. Some patients show intermittent claudication, while others show persistent radiological nerve root symptoms, mostly soreness, numbness, swelling and pain, with different degrees of pain. The location of nerve root symptoms is related to the compressed nerve root, which is manifested as reduced pinprick sensation, abnormal pain sensation, reduced muscle strength and abnormal tendon reflexes in the corresponding nerve root distribution area.
4. Cauda equina compression: Lumbar spinal stenosis can lead to compression of the cauda equina nerve, with symptoms and signs in the saddle area and symptoms of the sphincter, and in severe cases, symptoms of urinary and faecal and sexual disorders.
Diagnosis of lumbar spinal stenosis: Appropriate auxiliary examination methods should be selected according to clinical manifestations, such as X-ray plain film, myelography, CT scan, CT myelography, MRI, etc. by various projection methods to make accurate localization, qualitative and quantitative diagnosis. The biggest difference with lumbar disc herniation is that lumbar disc herniation generally does not have the three major symptoms of intermittent claudication, inconsistency between the chief complaint and objective examination, and limitation of lumbar back extension. The flexion neck test and straight leg raising test of lumbar disc herniation are mostly positive, while the lumbar spinal stenosis is negative. In addition, there is a clear difference between lumbar spinal stenosis and lumbar disc herniation in imaging, i.e., lumbar spinal stenosis shows less than normal sagittal signs of the spinal canal on CT, MRI, and myelography, while lumbar disc herniation does not. The two are two separate diseases, but at the same time there is a certain connection, and they can occur together, and the percentage of concomitant occurrence is quite high, which is the reason why people tend to confuse them. This is because in the later stages of lumbar disc herniation, synovial inflammatory exudative reaction, articular cartilage wear and tear and fragmentation occur in the corresponding small joints, leading to the development of hyperplastic bone flaps at the lateral posterior edge of the vertebral body and the articular eminence, secondary to lumbar spinal stenosis. When the two diseases occur together, the patient may exhibit symptoms and signs of both, and clinical diagnosis is not difficult.
Symptoms of lumbar spinal stenosis
The symptoms of lumbar spinal stenosis can be obvious with symptoms of lumbar pain and intermittent claudication. Patients often have lumbar and leg pain when walking one or two hundred meters, and the symptoms will be alleviated or disappear immediately after bending down and resting for a while or squatting, and if they continue walking again, the pain will appear again soon. The symptoms are aggravated when the spine is posteriorly extended and reduced when it is forward flexed. In a few cases, the compression of the cauda equina and nerve roots affects the bowel and urine, and even causes incomplete paralysis of the lower extremities. Patients with spinal stenosis often have more complaints but fewer signs. On examination, the spinal deflection is not obvious, the lumbar spine is normal, and only posterior extension pain is present. Straight leg raise test is normal or only moderate pulling pain. In a few patients, the muscles of the lower extremities are atrophied and the Achilles tendon reflex is sometimes diminished or absent.
Non-surgical treatment
In the past, early surgery was advocated for symptomatic lumbar stenosis because it was thought to be progressive; however, recent studies have shown that a phase of conservative treatment should be followed by a determination of the need for surgery.
Non-surgical treatment options include medication, activity modification, bracing, and epidural hormonal closure. None of these methods has been proven to be effective. Non-steroidal anti-inflammatory drugs have an analgesic effect in addition to reducing the inflammatory response due to nerve compression. These drugs are more frequently used, but no studies have been seen to obtain definite efficacy in the treatment of lumbar spinal stenosis. Paracetamol affects liver and kidney function, and non-steroidal anti-inflammatory drugs can cause gastric and duodenal ulcers, which also affect liver and kidney function, and should be used with care. The results of a double-blind cross-comparison study showed that intramuscular calcitriol (Calcitonin) reduced pain and increased walking distance.
More effective physical therapy for lumbar spinal stenosis is tensile (stretching) therapy, lumbar strength exercises and anaerobic health training. Riding a stationary bicycle is effective for some patients, and this exercise is tolerated by most patients in a flexed position. Bicycle walking exercises designed with a harness are also useful for patients with lumbar spinal stenosis because the lumbar spine is not under stress. There are more methods used for soft tissue physiotherapy, including: heat therapy, ice therapy, ultrasound, massage, electrical stimulation and traction, etc. Although more commonly used, the efficacy of lumbar spine disorders has not been confirmed. However, it is still beneficial to prepare for assisted lumbar spine activity and stronger physical therapy. Forging and physical therapy are safer and can delay surgical treatment, and forging can improve the patient’s general condition and facilitate better access to surgical treatment, even if it does not reduce symptoms.
Lumbar girth protection can increase the stability of the lumbar spine to reduce pain, but should be applied for a short period of time to avoid lumbar muscle atrophy.
Epidural hormone closure for lumbar spinal stenosis remains controversial and is generally considered to be less effective for the treatment of radicular pain. cuckler et al. prospectively studied a group of patients for the relief of radicular pain, and the results of a double-blind crossover comparison study showed no significant difference between the control group (epidural saline injection) and the experimental group (epidural hormone injection). rosen et al. retrospectively studied a group of patients treated with epidural hormone therapy, 60% had short-term relief of pain symptoms and only 25% had long-term relief of pain symptoms.
The results of Derby et al. showed that good response to epidural hormone closure therapy and satisfactory results of its surgical treatment, and poor response to epidural hormone closure therapy and unsatisfactory results of its surgical treatment, caused instability in 50% of radicular pain, and spinal fusion should be performed simultaneously to prevent postoperative spinal instability or pain. The stability of the spine can be maintained if the integrity of at least one small joint is preserved. However, biomechanical studies have shown that after unilateral subtotal joint resection (indicating a significant increase in joint step mobility), instability will occur even with good integrity on the other side and unilateral or bilateral subtotal joint medial partial resection.