Pierre Robin syndrome is a genetically determined anomaly characterized by hypoplasia of the mandible, palatine cleft and glossoptosis. The combination of MFR causes difficulty in feeding, obstructive apnea, diffuse cyanosis, the risk of food aspiration and asphyxia. Pathology is diagnosed according to radiography and CT of the jaw, fibrolaryngoscopy, polysomnography, genodiagnostics. Conservative tactics include positional therapy, CPAP, orthodontic treatment. Methods of surgical correction of the defect are represented by glossopexy, palate plasty, compression-distraction osteosynthesis.
Q87.0 Syndromes of congenital anomalies affecting mainly the appearance of the face
Robin’s syndrome (sequence, anomaly) includes a triad of signs: micrognathia, glossoptosis, splitting of the hard and soft palate. Congenital anatomical deformity was described in 1923 by the French dentist Pierre Robin. According to various estimates, children with this anomaly are born with a population frequency of 1:8500-30000, regardless of gender. The leading problem of infants with Robin syndrome is obstruction of the upper respiratory tract and critical respiratory failure due to underdevelopment of the lower jaw and displacement of soft tissues deep into the oral cavity.
Pierre Robin sequence can occur as an isolated syndrome (20-40%) or as part of other genetic pathologies. In the first case, the maxillofacial anomaly is formed under the influence of unfavorable conditions of intrauterine development, among which there may be:
- mechanical compression of the fetus in the uterine cavity, limiting the growth of the jaw (scars, amniotic cords, tumors or other fetus in multiple pregnancies);
- intrauterine infections;
- folic acid deficiency in the pregnant woman’s body;
- teratogenic effects on the fetus caused by harmful environmental factors, radiation, chemicals, taking drugs.
In addition, Pierre Robin’s anomaly is found in the structure of genetic syndromes with multiple malformations. In total, there are about 300 such diseases, including Stickler, Hangart, Edwards syndromes, campomelic dysplasia, etc. In more than 30% of cases, Pierre Robin syndrome is combined with CHD, skeletal abnormalities, defects in the development of eyes and auricles.
Sporadic cases occur as a result of de novo genetic mutations. The syndromic sequence is inherited according to the same principle as the pathology with which it is associated (an autosomal recessive, autosomal dominant, X-linked variant is reported). According to research, genetic mutations affect regions of chromosomes 2 (2q24.1-33.3), 4 (4q32-qter), 11 (11q21-q23.1) and 17 (17q21-q24.3).
Pierre Robin syndrome is commonly referred to as a “sequence”, since its signs are a chain of mutually influencing events. Violation of the development of the lower jaw in the fetus occurs between the 7th and 11th weeks of gestation under the influence of genetic mutations or exogenous factors. Hypoplasia of the jaw contributes to the incorrect position of the tongue between the palatine plates, which prevents their timely closure and causes the formation of a cleft.
The lower retrognathia and the small volume of the oral cavity create conditions for the displacement of the tongue towards the posterior wall of the pharynx and the occurrence of glossoptosis. The tongue pulled back causes serious breathing difficulties in the newborn, as a result of which inspiratory obstruction of the VDP often occurs.
Depending on the severity of swallowing and breathing disorders, there are three degrees of severity of Pierre Robin syndrome:
- light – breathing is not disturbed, there are minor difficulties when feeding the baby, which are eliminated by conservative methods at home;
- average – breathing and feeding difficulties are moderate, the child needs inpatient care, probe nutrition;
- severe – severe breathing difficulties and self-feeding, requiring the installation of a tracheostomy and a gastric probe.
Newborns with Pierre Robin syndrome have a characteristic “bird-like” face caused by hypoplasia of the mandible (micrognathia) and its displacement backwards (retrognathia). The volume of the oral cavity is reduced, the tongue is pulled deep (glossoptosis). As a rule, patients have a U-shaped submucous cleft of the soft palate, and a Gothic palate is also found.
The displacement of the tongue posteriorly causes problems with sucking at an early age, which is why the child has a delay in growth and weight gain, a lag in motor development. The severity of respiratory disorders varies from snoring to dangerous episodes of obstructive apnea. In mild cases, respiratory disorders occur only in the position on the back and when the child is worried, they pass on their own. In more serious situations, respiratory arrest attacks are prolonged (up to 20 seconds. and more), leading to the development of hypoxia and hypercapnia.
Severe episodes of apnea are accompanied by acrocyanosis or diffuse cyanosis. The constant involvement of the auxiliary respiratory muscles contributes to the formation of a funnel-shaped deformation of the chest.
The Pierre Robin syndrome sequence is usually combined with congenital anomalies of other organs: hearing loss and underdevelopment of the hearing aid, pathology of the visual analyzer (myopia, cataract), skeletal deformities (polydactyly, congenital amputations), heart defects. Approximately half of the patients have CNS defects: microcephaly, hydrocephalus, epilepsy, delayed speech development, oligophrenia.
Almost all children with Pierre Robin syndrome suffer from speech defects (open rhinolalia), malocclusion, recurrent ear infections. Against the background of prolonged attacks of obstructive apnea, hypoxic encephalopathy, pulmonary heart is gradually formed. In some cases, the child may die from asphyxia. Dysphagic disorders can lead to aspiration of saliva, food, gastric contents during regurgitation, which is fraught with the development of aspiration pneumonia. The mortality rate of children is about 16%, and in the presence of combined defects reaches 41%.
Currently, Pierre Robin syndrome is diagnosed prenatally by screening ultrasound at 11-12 weeks of pregnancy. After birth, the diagnosis is confirmed by the data of the clinical picture and instrumental studies. Necessary diagnostics:
- X-ray methods. For the initial assessment of the anatomy of the maxillofacial zone, radiography of the lower jaw, larynx and trachea is performed. As part of the preoperative examination, CT scans of the jaws, facial skull, and soft tissues of the neck are mandatory. X-ray imaging helps to determine the degree of micro- and retrognathia, airway obstruction, and calculate distraction parameters.
- Laryngeal endoscopy. With the help of fibrolaryngoscopy, the condition of the nasopharynx, larynx and the initial trachea is clarified. The level and degree of obstruction of the VDP are assessed, other anomalies of the ENT organs are detected.
- Polysomnography. It is considered the “gold standard” for determining the severity of obstructive apnea syndrome. With its help, the frequency and duration of episodes of respiratory arrest are found out, the optimal therapy is selected.
- Other methods. Blood gas composition and pulse oximetry are regularly examined. Before the planned operation, a photo fixation of the child’s appearance in the full face and profile, bite registration is performed. In the syndromic forms of Robin’s anomaly, gene diagnostics is indicated.
Therapeutic tactics for Robin’s anomaly depends on the severity of respiratory and dysphagic disorders. It may consist in carrying out positional therapy, auxiliary therapy, surgical treatment. At various stages of life, the child needs the support of an otolaryngologist, maxillofacial surgeon, orthodontist, speech therapist.
With a mild degree of respiratory obstruction, postural therapy is recommended. The child is laid out on his stomach or on his side with his head raised or fixed, ensuring that the tongue and lower jaw are pushed forward. Persistent obstruction can be stopped with the help of a nasopharyngeal duct. One of the methods with proven effectiveness is CPAP therapy, which allows noninvasive mask ventilation under constant positive pressure.
If it is impossible to self-feed, the baby is fed through a nasogastric probe. Severe degrees of Pierre Robin syndrome require the installation of a tracheostomy or tracheal intubation with the connection of the child to a ventilator.
Conservative methods allow you to stop the symptoms, but none of them eliminates the existing congenital anomalies. Therefore, such treatment should be carried out for a very long time, as long as the size of the child’s airways does not allow him to breathe independently without the risk of obstruction. After normalization of vital functions, orthodontic treatment and speech therapy correction are performed.
Elimination of the palatine cleft is carried out in stages: velopharyngoplasty is performed in 6-8 months, uranoplasty – in 12-18 months. As a temporary measure in preparation for radical treatment, glossopexy can be performed – fixing the tongue to the lower lip, alveolar process. Previously used methods of stretching the mandible, transposition of the masticatory muscles are not sufficiently effective.
A radical surgical intervention that allows to lengthen the lower jaw is compression-distraction osteosynthesis. The operation consists in performing a bilateral osteotomy of the lower jaw with fixation on bone fragments of a special device. Activation of the device provides gradual movement of the lower jaw along with the complex of soft tissues of the bottom of the oral cavity anteriorly. The distraction process takes about 3 months, as a result of which independent breathing becomes possible first, and then nutrition.
Prognosis and prevention
Isolated Robin syndrome has a more favorable prognosis than the syndromic forms associated with multiple defects and mental retardation. The timeliness and radicality of treatment is also essential. At the same time, at the moment, the mortality rate from asphyxia, other complications and concomitant anomalies remains quite high.
To reduce the risk of having a child with Pierre Robin syndrome, it is recommended to avoid exposure to teratogens, infection, and micronutrient deficiency during gestation. Pregnant women need to undergo genetic and ultrasound prenatal screenings in time.