Sacralization is a congenital anomaly of the spine, in which the V lumbar vertebra fully or partially fuses with the sacrum. It is the opposite of lumbalization and together with it refers to malformations of the “transitional lumbosacral vertebra” type. It is widespread, often asymptomatic, less often accompanied by pain syndrome. It can provoke accelerated development of osteochondrosis and spondyloarthrosis. The diagnosis is made on the basis of radiography and CT. Treatment is usually conservative: physical therapy, physiotherapy, massage.
Q76.4 Other congenital spinal anomalies not related to scoliosis
Sacralization is a congenital malformation, a decrease in the number of lumbar vertebrae due to the fusion of the V lumbar vertebra with the sacrum. The opposite of lumbarization, in which the I sacral vertebra does not fuse with the rest, and the patient forms six lumbar and 4 sacral vertebrae. Sacralization is a fairly widespread anomaly and is often combined with other malformations of the spine.
Various forms of sacralization are detected in 15% of men and 7% of women, and the tendency to sacralization is seen in almost half of people who have undergone radiography of the lumbar and sacral spine. At the same time, this pathology is asymptomatic in most cases and causes the development of pain syndrome in only 2% of the total number of patients who sought medical help due to back pain. Treatment of sacralization is carried out by doctors-vertebrologists, orthopedists-traumatologists.
The immediate cause of the occurrence of transitional lumbosacral vertebrae (sacralization and lumbalization) has not yet been precisely established. Some researchers believe that these developmental anomalies are formed as a result of violation of the bookmarks of ossification points in the embryonic period. If there are extra ossification points, sacralization is formed, if there are a lack of such points, lumbalization is formed.
In traumatology and orthopedics , the following forms of sacralization are distinguished:
- Bony bilateral – both transverse processes of the V lumbar vertebra fuse with the lateral masses of the sacrum.
- Bone unilateral – one transverse process merges with the lateral mass of the sacrum, and synchondrosis (cartilaginous fusion) is formed on the other side, or the transverse process remains free.
- Cartilaginous bilateral – both transverse processes form synchondrosis with lateral sacral masses.
- Cartilaginous unilateral – one transverse process forms synchondrosis with the lateral mass of the sacrum, the second remains free.
- Articular bilateral – both transverse processes form abnormal joints (neoarthrosis), connecting with the lateral masses of the sacrum.
- Articular unilateral – one transverse process forms neoarthrosis with the lateral mass of the sacrum, the second remains free.
With bone sacralization, the intervertebral disc is either absent or presented in a rudimentary form, the arch-process joints are overgrown. Due to one- or two-sided bone fusion, movements in the segment are completely excluded. In the cartilaginous form of pathology, the intervertebral disc is usually present, but has a rudimentary appearance. Cartilage fusion, especially bilateral, in most cases ensures the immobility of the segment.
With articular sacralization, the intervertebral disc is present, its height is slightly reduced compared to the norm. Arch-process joints are preserved. The segment retains mobility in most cases. With unilateral cartilaginous and, especially, articular sacralization, scoliosis is often observed due to the wedge-shaped lateral deformation of the body of the V lumbar vertebra, there is a higher predisposition to the early occurrence of dystrophic changes in the vertebrae and intervertebral discs.
In addition to true sacralization, in some cases, false sacralization may be detected due to pathological processes in the lumbar spine and accompanied by ossification of the ligaments. The characteristic features of this form of sacralization are the senile age of the patient, the late onset of symptoms and the presence of previous spinal diseases (fracture of the lumbar spine, spinal osteochondrosis, lumbar spondylosis or spondyloarthrosis).
There are three possible variants of the course of pathology: asymptomatic (the anomaly becomes an accidental finding during radiography for another reason), with early and late onset. Asymptomatic course, as a rule, is observed with a fixed vertebra. With a movable vertebra, clinical manifestations occur early enough, sciatic or mixed form is more often detected, due to pinching or bruising of the nerve. The onset occurs at the age of about 20 years, for the first time the pain syndrome appears after excessive physical exertion, a sharp lateral inflection of the trunk, falling to the feet or jumping.
Early onset is characterized by pain radiating to the lower extremities, sometimes pain is preceded by paresthesia. A typical sign is a weakening of pain when lying down and an increase in pain syndrome when lowering on the heels, jumping or staying in a standing position. The later occurrence of pain syndrome is caused by secondary changes in the joints and vertebra. Pains appear in middle or old age and, unlike the previous variant, are localized only in the lumbar region. Ischialgic syndrome is rarely observed.
The main technique used to confirm the diagnosis of sacralization is radiography of the lumbosacral spine. It should be borne in mind that radiologically sacralization and lumbarisation look almost identical, to determine the type of transitional vertebra, it is necessary to count the number of lumbar and sacral vertebrae. The forms of sacralization can be different, the images may reveal an increase in transverse processes that take the form of a butterfly wing or fan, a complete or partial connection of the body and processes with the sacrum.
A characteristic feature is a decrease in the height of the transitional vertebra and a narrowing or absence of the gap between the transitional vertebra and the sacrum. A shortening of the spinous process is revealed, which may rest against the crest of the sacrum or merge with it together with the supporting arch. The nerve outlet spaces may remain unchanged or take the form of holes similar to the holes in the sacrum. In the presence of neoarthrosis in newly formed joints, signs of arthrosis, degeneration of articular processes and the formation of ossifications at the edges of the articulation are often revealed. These pathological changes are especially pronounced in scoliosis.
Using X-rays, it is possible to differentiate true sacralization from pseudo-sacralization. With false sacralization, the intervertebral space is preserved, partially obscured by ossified ligaments. The radiographs show the shadows of ossified ligaments extending from the iliac bones to the transverse processes. Multiple ossifications are detected on the vertebral body.
With an asymptomatic course, special treatment is not required. With pain syndrome, conservative measures are carried out: physiotherapy procedures are prescribed (electrophoresis with novocaine, ultrasound, paraffin applications), physical therapy and massage of the lumbosacral region, blockades with novocaine and corticosteroid drugs are performed. If possible, the patient is referred for sanatorium treatment. It is recommended to use a special corset and exclude heavy physical labor. If necessary, anti-inflammatory and painkillers are prescribed.
Indications for surgery are persistent pain that cannot be corrected using conservative methods of treatment. Surgical intervention is carried out as planned in the conditions of an orthopedic or vertebrological department. During the operation, the doctor removes the enlarged transverse process that forms a movable joint with the sacrum, and performs spinal fusion using a bone graft. In the postoperative period, physiotherapy, physical therapy, antibiotics and painkillers are prescribed.