Most patients with degenerative scoliosis are older than 50 years old, and with the aging of our population, adult scoliosis will become more common. The main focus is on symptom relief, and as much as possible, simple, convenient, and less invasive treatment methods are chosen as long as they can ensure a certain quality of life for the patient. This issue will detail the various diagnostic modalities for degenerative scoliosis, including symptoms, physical examinations, and imaging tests.
Symptoms
The main symptoms of patients with degenerative scoliosis are low back pain, radiating pain in the lower extremities and intermittent claudication most often.
1.Lower back pain
Low back pain is the most common first and main symptom, which can last for months to decades. Back pain occurs in the upright position with weight, and cannot be relieved by sitting and squatting, but can be significantly relieved by lying down, so it is also called “postural back pain”. The pain of DS can be mechanical pain, spinal stenosis pain, or a combination of both. it is generally accepted that it is not easy to determine the exact site of origin of the pain, and that scoliosis may be only one of the causes of the pain. Muscle fatigue and strain on the convex side may be the most important cause of pain, and symptoms can be significantly aggravated when lumbar extension activities are performed; while when pain appears on the concave side, symptoms mainly originate from degeneration of the intervertebral discs, small joints, etc. The pain is more obvious when scoliosis combined with the anterior lumbar convexity angle becomes small.
2.Scoliosis
Most patients have lumbar curvature and thoracolumbar segment curvature, with lumbar curvature being the most frequent. In male DS patients, the left-sided convexity of the main curve is roughly equivalent to the right-sided convexity, and female patients have significantly more left-sided convexity than right-sided convexity. The lateral convexity angle is smaller than that of adults, and the involved segments are usually smaller; the location of the parietal vertebrae is usually located in L2~L3 or L3~L4, but may also be located in L1 and L2, mostly accompanied by intervertebral lateral displacement, vertebral body rotation and spinal stenosis.
3.Nerve root compression symptoms
Nerve root symptoms such as radiating pain, numbness and weakness of the lower extremities can occur in both lower extremities. Radiating pain is usually seen in the convex lower extremity, and the rest of the symptoms are seen in the concave lower extremity; L4/L5 nerve root compression is the most common. Nerve root compression may be caused by nerve root pulling and compression due to arch root displacement, vertebral body rotation, lateral slipped articular proliferation, lateral saphenous fossa stenosis, disc herniation and negative gravity line change. Clarifying the cause of nerve root compression can help clarify the scope of surgical decompression.
4.Neural claudication
It is caused by the combination of degeneration and scoliosis deformity resulting in lumbar spinal stenosis. Spinal stenosis most often occurs in the parietal segment of the lateral main bend (either concave or convex) and is associated with varying degrees of structural rotational deformity.
Characteristically, patients cannot achieve symptomatic relief by anterior lumbar flexion alone or by adopting a sitting position; these patients need to support their trunk with their upper extremities or adopt a supine position, which allows them to achieve symptomatic relief from neurologic claudication. The symptoms of neurologic claudication and vascular claudication may overlap and require careful evaluation.
Physical examination
In addition to the general condition, standing posture and gait, whether the shoulders and pelvis are tilted or horizontal, whether there is a flat back or kyphotic deformity of the low back, razorback deformity when bending, abdominal collapse, skin folds, etc. A detailed neurological examination, including muscle strength, sensation, physiological and pathological reflexes, straight leg raise test, femoral nerve pull test, etc., is also required. The pulsatility of the distal limb must be checked to help rule out peripheral vascular disease and vascular claudication.
Imaging examinations
1.X-ray examination
A standing full spine image is required routinely. Degenerative scoliosis is well defined, with isolated lumbar scoliosis and degenerative disc degeneration. In some patients, there may be a reduction in normal lumbar lordosis and significant lumbar rotational subluxation with varying degrees of lateral displacement of the vertebrae. Lateral flexion films can provide additional information when planning surgery. Lateral flexion-extension films can show lumbar instability, and Ferguson anteroposterior images can show significant degenerative changes in the lumbosacral joint and better visualize the transverse processes of L5. The presence of transverse process hypoplasia also suggests consideration of interbody fusion, as the implant bed is too small for intertransverse process grafting in this case, especially in lumbosacral fusion.
2.CT and MRI examination
can provide reliable information on the internal diameter of the spinal canal, the degree and extent of spinal cord and nerve root compression, and the degeneration of the intervertebral disc in the relevant segment, which is indispensable for the diagnosis and treatment of the disease.
CT myelography (CTM): Since it is difficult to obtain images parallel to the intervertebral disc space when MRI is performed in patients with scoliosis, myelography is better used in showing the spinal canal and nerve roots. A myelogram should be taken of the patient in the standing position in flexion and extension, which must be followed by a CT examination. Images in the power position can show compression of the nerve roots that cannot be shown in the supine position.
3.Other
Electromyography (EMG) and nerve conduction velocity examinations are helpful in differentiating peripheral neuropathy from other diseases, especially in diabetic patients. In addition, arterial Doppler and angiography are required in some patients, and the use of the bike-plate test, a non-invasive functional test, is also helpful in differentiating neurological and vascular claudication.
Diagnosis and differential diagnosis
Based on the clinical features of degenerative scoliosis, a detailed history of the patient should be taken, focusing on the presence of a family history of scoliosis, the presence of back pain, the presence of neurogenic claudication, the presence of spinal imbalance or significant deformity, and the time of appearance of these symptoms.
Physical examination should include, in addition to a complete neurological examination, an examination of the pelvis, low back, trunk, and shoulders, and measurement of range of motion and lower extremity length. Imaging examinations should firstly take anterior and lateral radiographs after uprighting, followed by anterior flexion, posterior extension and lateral flexion position films to further assess the flexibility of scoliosis and the stability of motor segments. Myelography, CT or MRI can be used to diagnose spinal canal or intervertebral foraminal stenosis, etc.
It needs to be differentiated from adult idiopathic scoliosis (IS). IS is more common before the age of 30 years and is more common in the thoracic segment, followed by the thoracolumbar segment, and less common in the lumbar segment site alone. IS can involve 7-11 segments and the Cobb angle is often larger, but often without neurological symptoms. In addition, in elderly patients who have recently developed symptoms of low back pain, despite the presence of degenerative scoliosis, tumors or other diseases such as osteoporosis, diabetes mellitus, and cardiopulmonary disease should still be excluded.