Caudal regression syndrome is a congenital pathology resulting from dysembriogenesis of the lower parts of the spinal column and spinal cord. It is clinically manifested by a decrease in the height of the lumbar spine and sacrum, hip dislocations, muscle weakness and hypotrophy of the legs, pelvic dysfunction. It is diagnosed according to the examination, neurological examination, spondylography, MRI of the spine and spinal cord. In order to improve the supporting function of the pelvis, prevent compression of organs, restore the ability to move, a phased surgical correction of existing deformities is carried out.
ICD 10
Q 76.4 Other congenital spinal anomalies not associated with scoliosis
Meaning
Caudal regression syndrome (caudal dysgenesis, lumbosacral agenesis) is a severe underdevelopment of the lower half of the body resulting from disorders of embryogenesis. Pathology includes a wide range of congenital anomalies affecting the distal part of the spine and spinal cord, large intestine, genitourinary system. The syndrome occurs in one in 25,000 newborns. The prevalence among children from mothers with diabetes is 1 case per 350 newborns. The extreme form of this pathology is sirenomyelia (mermaid syndrome) — fusion of the lower extremities, described in detail in 1961 in the UK by pediatrician B. Duhamel.
Causes
The etiofactors leading to the occurrence of regression have not been definitively determined. The vast majority of cases are sporadic. Some researchers point to the detection of mutations in the VANGL 1 gene in some patients that were inherited by an autosomal dominant type.
Risk factors for the appearance of a gene mutation and sporadic cases of embryogenesis pathology are teratogens that affect the mother’s body during pregnancy. Many medications, toxic and narcotic substances, increased radiation background, viruses have a teratogenic effect. Insulin-dependent diabetes mellitus in the mother is recognized as the most significant teratogenic factor in the occurrence of the syndrome. Fluctuations in blood glucose levels, the presence of diabetic angiopathy lead to a violation of blood supply in such cases.
Pathogenesis
The above-mentioned etiofactors lead to violations of the embryogenesis process, as a result of which an abnormal vessel develops in the fetus, shunting blood from the upper half of the trunk directly into the placenta. Blood discharge leads to a lack of adequate blood supply to the lower part of the body, which entails multiple malformations.
The underdevelopment of the vertebrae is combined with a violation of the differentiation of the caudal cell mass of the embryo, giving rise to the spinal cord cone, thread and distal nerve roots. The resulting spinal regression is accompanied by a disorder of innervation of developing tissues and internal organs of the affected area, which acts as an additional factor of dysgenesis.
Classification
Since caudal regression has a wide range of variability, it is necessary to divide it into clinical forms. Several classifications have been proposed throughout the history of the study of the disease. The first one was created in 1978 and identifies 4 variants of pathology:
- 1 – unilateral sacral agenesis;
- 2 – bilateral sacral agenesis;
- 3 – lumbosacral agenesis, accompanied by the junction of the iliac bones with the lateral surfaces of the last available vertebra;
- 4 — lumbosacral agenesis, in which the iliac bones are located under the lowest vertebra.
The classification of 2002 is considered to be more perfect, taking into account not only the clinical and radiological picture, but also the prospect of independent movement of the patient. According to this classification , the caudal regression syndrome is divided into 3 types:
- Type A — agenesis of 1-2 lumbar vertebrae, fusion of the iliac bones or a small distance between them. The sacral vertebra connects to the pelvis in the middle.
- Type B — absence of several lumbar segments, complete connection of the iliac bones, the sacral vertebra is attached to one of them.
- Type C — total agenesis of the lumbar vertebrae, pronounced distance between the pelvis and the thoracic region.
Symptoms
The clinic of the syndrome depends on its type, the degree of spinal dysplasia. Patients have hypoplasia of the legs and shortening of the trunk, which leads to low growth. With partial agenesis of type A, the patient retains the ability to walk. The other types are accompanied by the inability to fully stand, walk.
The higher position of the iliac bones leads to congenital dislocations in the hip joints. Equinovarus deformation of the feet is observed. Severe caudal regression is characterized by a “frog pose” in which the hips are rotated outward and retracted, the legs are bent at the knee joints.
The underdevelopment of the lower spinal segments leads to a violation of the innervation of the muscles of the lower extremities, the perineum with their hypotrophy, a decrease in muscle strength. There is a flattening of the buttocks, a conical shape of the legs. In some cases, there is a bend of the popliteal fossa. Sensory disorders are possible. A typical violation of pelvic functions: urinary incontinence, less often — feces. Often, caudal regression is accompanied by other malformations: atresia of the anus, omphalocele, kidney defects, diastematomyelia.
Complications
Caudal regression syndrome is a disabling disease. In the absence of surgical correction of the defect and rehabilitation measures, muscle hypotrophy develops into irreversible atrophy. The lack of motor activity in the joints of the legs leads to their flexion contractures. The proximity of the pelvis to the chest leads to the development of kyphoscoliotic curvature. Vertebral-pelvic instability is complicated by compression and deformation of internal organs.
Diagnostics
Examination of a patient with caudal regression syndrome allows a neurologist to identify characteristic dysemriogenetic signs, a disturbed ratio of the chest and pelvis, the presence of flexor contractures. In the neurological status, there is lower paraparesis or plegia, a decrease in muscle tone, a decrease in tendon reflexes. Hypesthesia is not observed in all cases of the syndrome. To confirm the diagnosis, clarify the degree of morphological abnormalities and the level of spinal cord damage, the following instrumental studies are necessary:
- Spondylography. The most accessible diagnostic method. Allows to evaluate morphological deviations in the structure of bone structures: the level of the end of the spine, concomitant pathology, stenosis of the dural sac.
- CT of the spine. Allows you to visualize bone anomalies in more detail, to identify stenosis of the distal spinal canal.
- MRI of the spine. Along with the visualization of bone structures, it is more informative in the diagnosis of the state of the spinal cord. In most cases, it demonstrates the end of the brain above the level of the abnormal vertebra. The final part of the brain is visualized in the form of an onion or a bend.
Caudal regression syndrome can be suspected when an abnormally shortened sacrum is detected during ultrasound in the first trimester of pregnancy. Ultrasound in the second or third trimester may show the absence of the sacrum, shortening of the femurs, clubfoot, concomitant abnormalities of the kidneys and intestines.
Differential diagnosis
In patients with caudal regression syndrome, there is no motor function below the level of the remaining normal spine, there is a violation of the pelvic organs, which is typical for myelomeningocele. However, with myelomeningocele, there is a herniated protrusion in the spine, the function of the sensitive nerves is disrupted below the level of the affected vertebrae. In caudal regression syndrome, sensitivity tends to persist much higher than the caudal level.
Treatment
Caudal dysgenesis requires an interdisciplinary complex and step-by-step approach in therapy. The choice of therapeutic tactics is carried out individually and is aimed at improving the quality of life of the patient. Drug therapy is necessary to prevent complications and compensate for disorders caused by abnormalities of organs and systems. Rehabilitation measures should be carried out constantly.
Surgical treatment
Most specialists in the field of neurology and orthopedics advise using active surgical tactics in patients with pelvic-vertebral instability, considering its elimination necessary to prevent deformation of internal organs. Some doctors consider the preservation of instability more convenient for a sitting position in patients with the inability to restore walking. In general, surgical interventions performed with caudal regression include:
- Vertebral-pelvic fixation. Involves fixing the pelvic bones to the spinal column. It is carried out with the use of metal structures. The operation involves the elimination of spinal canal stenosis and correction of concomitant spinal anomalies, which leads to an improvement in nerve functions.
- Elimination of hip dislocations. It is necessary for patients with potentially possible restoration of walking function, as well as to facilitate sitting in a wheelchair. The most common technique is considered to be a subtrochanteric osteotomy. In the early period, it is possible to carry out an open reduction.
- Elimination of knee contractures. It is performed with the installation of a Z-shaped popliteal plate and the imposition of a distraction apparatus for gradual extension of the knee. After surgical treatment, relapses are possible.
- Correction of clubfoot. It is carried out by triple arthrodesis. Allows you to restore the foot supportability.
Experimental treatment
Since multiple pathology of the lower extremities (dislocations, contractures, clubfoot) requires numerous surgical operations, prosthetics of the legs was proposed as a new approach in the treatment of the syndrome. Many authors consider bilateral subtrochanteric amputation or dearticulation at the knee joint level with subsequent prosthetics to be a promising method. According to the researchers, this method of treatment will allow patients to sit without support on their hands, to move independently.
Prognosis and prevention
Severe forms of caudal regression syndrome, combined with pathology of internal organs, can lead to early neonatal death due to problems with the heart, kidneys and respiratory tract. The degree of recovery of motor function and reduction of neurological deficit as a result of surgical interventions depends on the type of syndrome and the quality of postoperative rehabilitation. Prevention is aimed at protecting pregnant women from exposure to potential teratogens, maintaining normal glucose levels in patients with diabetes mellitus, especially at the beginning of pregnancy.
Literature
- Duhamel B. From the mermaid to anal imperforation: The syndrome of caudal regression. Arch. Dis. Child. 1961;36:152–155. link
- Ferrer-Vaquer A., Hadjantonakis A.-K. Birth defects associated with perturbations in preimplantation, gastrulation, and axis extension: From conjoined twinning to caudal dysgenesis. Wiley Interdiscip Rev. Dev. Biol. 2012;2:427–442. link
- Singh S.K., Singh R.D., Sharma A. Caudal regression syndrome—Case report and review of literature. Pediatr. Surg. Int. 2005;21:578–581. doi: 10.1007/s00383-005-1451-4. – DOI – PubMed
- Thottungal A.D., Charles A.K., Dickinson J.E., Bower C. Caudal dysgenesis and sirenomelia-single centre experience suggests common pathogenic basis. Am. J. Med. Genet. Part A. link
- Garrido-Allepuz C., Haro E., González-Lamuño M., Martínez-Frías M.L., Bertocchini F., Ros M.A. A clinical and experimental overview of sirenomelia: Insight into the mechanisms of congenital limb malformations. Dis. Model. Mech. link