Pierre Robin sequence
Pierre Robin sequence | |
---|---|
Other names | Pierre Robin syndrome, Pierre Robin malformation, Pierre Robin anomaly, Pierre Robin anomalad |
Usual onset | During gestation, present at birth |
Causes | intrauterine compression of fetal mandible or de-novo mutations (on chromosomes 2, 4, 11, or 17) |
Diagnostic method | Physical examination |
Treatment | Craniofacial surgery, oral and maxillofacial surgery |
Frequency | 1 in 8,500 to 14,000 people[2] |
Pierre Robin sequence
Signs and symptoms
PRS is characterized by an unusually small mandible, posterior displacement or retraction of the tongue, and upper airway obstruction. Cleft palate (incomplete closure of the roof of the mouth) is present in the majority of patients. Hearing loss and speech difficulty are often associated with PRS.[citation needed]
Causes
Mechanical basis
The physical craniofacial deformities of PRS may be the result of a mechanical problem in which intrauterine growth of certain facial structures is restricted, or mandibular positioning is altered.[4] One theory for the etiology of PRS is that, early in the first trimester of gestation, some mechanical factor causes the neck to be abnormally flexed such that the tip of the mandible becomes compressed against the sternoclavicular joint. This compression of the chin interferes with development of the body of the mandible, resulting in micrognathia. The concave space formed by the body of the hypoplastic mandible is too small to accommodate the tongue, which continues to grow unimpeded. With nowhere else to go, the base of the tongue is downwardly displaced, which causes the tip of the tongue to be interposed between the left and right palatal shelves. This in turn may result in failure of the left and right palatal shelves to fuse in the midline to form the hard palate.[1] This condition manifests as a cleft palate. Later in gestation (at around 12 to 14 weeks), extension of the neck of the fetus releases the pressure on the mandible, allowing it to grow normally from this point forward. At birth, however, the mandible is still much smaller (hypoplastic) than it would have been with normal development. After the child is born, the mandible continues to grow until the child reaches maturity.[citation needed]
Genetic basis
Alternatively, PRS may also be caused by a
PRS may occur in isolation, but it is often part of an underlying disorder or syndrome.
Diagnosis
PRS is generally diagnosed clinically shortly after birth. The infant usually has respiratory difficulty, especially when supine. The palatal cleft is often U-shaped and wider than that observed in other people with cleft palate.[citation needed]
Management
The goals of treatment in infants with PRS focus upon breathing and feeding, and optimizing growth and nutrition despite the predisposition for breathing difficulties. If there is evidence of airway obstruction (snorty breathing, apnea, difficulty taking a breath, or drops in oxygen), then the infant should be placed in the sidelying or prone position, which helps bring the tongue base forward in many children. One study of 60 infants with PRS found that 63% of infants responded to prone positioning.[10] Fifty-three percent of the infants in this study required some form of feeding assistance, either nasogastric tube or gastrostomy tube feedings (feeding directly into the stomach). In a separate study of 115 children with the clinical diagnosis of PRS managed at two different hospitals in Boston,[11] respiratory distress was managed successfully in 56% without an operation (either by prone positioning, short-term intubation, or placement of a nasopharyngeal airway). In this study, gastrostomy tube feeding were placed in 42% of these infants due to feeding difficulties.[citation needed]
In nasopharyngeal cannulation (or placement of the nasopharyngeal airway or tube), the infant is fitted with a blunt-tipped length of surgical tubing (or an endotracheal tube fitted to the child), which is placed under direct visualization with a laryngoscope, being inserted into the nose and down the pharynx (or throat), ending just above the vocal cords. Surgical threads fitted through holes in the outside end of the tube are attached to the cheek with a special skin-like adhesive material called 'stomahesive', which is also wrapped around the outside end of the tube (but not over the opening at the end) to keep the tube in place. This tube or cannula, which itself acts as an airway, primarily acts as a sort of "splint" which maintains patency of the airway by keeping the tongue from falling back on the posterior pharyngeal wall and occluding the airway, therefore preventing airway obstruction, hypoxia and asphyxia. Nasopharyngeal airways are not available at every center; however, when available, nasopharyngeal cannulation should be favored over the other treatments mentioned in this article, as it is far less invasive; it allows the infant to feed without the further placement of a nasogastric tube. This treatment may be utilized for multiple months, until the jaw has grown enough so that the tongue assumes a more normal position in the mouth and airway (at birth, the jaws of some infants are so underdeveloped that only the tip of the tongue can be seen when viewed in the throat). Some institutions discharge the infant home with a nasopharyngeal tube in place.[13]
Distraction osteogenesis (DO), also called a "Mandibular Distraction", can be used to correct abnormal smallness of one or both jaws seen in patients with PRS. Enlargement of the lower jaw brings the tongue forward, preventing it from obstructing the upper airway. The process of DO begins with preoperative assessment. Doctors use three-dimensional imaging to identify the parts of the patient's facial skeleton that need repositioning and determine the magnitude and direction of distraction. They may then select the most appropriate distraction device or sometimes have custom devices fabricated. When possible, intraoral devices are used.
DO surgery starts with an osteotomy (surgical division or sectioning of bone) followed by the distraction device being placed under the skin and across the osteotomy. A few days later, the two ends of the bone are very gradually pulled apart through continual adjustments that are made to the device by the parents at home. The adjustments are made by turning a small screw that protrudes through the skin, usually at a rate of 1 mm per day. This gradual distraction leads to formation of new bone between the two ends. After the process is complete, the osteotomy is allowed to heal over a period of six to eight weeks. A small second surgery is then performed to remove the device.
The cleft palate is generally repaired between the ages of 6½ months and 2 years by a plastic surgeon, an
A cleft palate (PRS or not) makes it difficult for individuals to articulate speech sounds, which may be due to the physical nature of cleft palate or the hearing loss that is associated with the condition.[14] This is typically why a speech language pathologist and/or audiologist is involved with the patient. Hearing should be checked by an audiologist regularly and can be treated with hearing amplification such as hearing aids. Because middle ear effusion is found in many patients with PRS, tympanostomy (ventilation) tubes are often a treatment option.[15]
One study with children showed that patients with PRS displayed a moderate and severe hearing loss most frequently.
Prognosis
Children affected with PRS usually reach full development and size. However, it has been found internationally that children with PRS are often slightly below average size, raising concerns of incomplete development due to chronic
The most important medical problems are difficulties in breathing and feeding. Affected infants very often need assistance with feeding, for example needing to stay in a lateral (on the side) or prone (on the tummy) position which helps bring the tongue forward and opens up the airway. Babies with a cleft palate will need a special cleft feeding device (such as the
Epidemiology
The prevalence of PRS is estimated to be 1 in 5,400 to 14,000 people.[2][16]
Hearing loss has a higher incidence in those with cleft palate versus non-cleft palate. One study showed hearing loss in PRS at an average of 83%, versus an average of 60% of individuals with cleft without PRS.[17] Another study with children showed that hearing loss was found more frequently with PRS (73.3%) compared to those with cleft and no PRS (58.1%).[15] Hearing loss with PRS typically is a bilateral, conductive loss (affecting the outer/middle portion of the ear).[17]
History
The condition is named for the French dental surgeon Pierre Robin.[18][19]
It is thought that
See also
References
- ^ PMID 4016420.
- ^ a b "Isolated Pierre Robin sequence". Genetics Home Reference. Bethesda, Maryland: United States National Library of Medicine. 2019. Retrieved May 11, 2019.
- ^ "merriam-webster.com – Pierre Robin syndrome". Retrieved 30 June 2019.
- ^ PMID 23633934.
- S2CID 25888887.
- PMID 23826492.
- PMID 17551083.
- S2CID 35802241. Archived from the originalon 2001-03-09.
- S2CID 12421132.
- ^ Smith and Senders, 2006, Int J Pediatr Oto
- ^ Evans et al., 2006, In J Pediatr Oto
- ^ Dudkiewicz, March 2000, CPCJ
- ^ KD Anderson, May 2007, CPCJ
- ^ Pierre Robin Syndrome - Birth Defect Fact Sheet, 2020
- ^ a b c d e Handžić-Ćuk, 2007
- S2CID 238532372.
- ^ a b Handžić et al, 1995
- Who Named It?
- ^ Pierre Robin. La glossoptose. Son diagnostic, ses consequences, son traitement. Bulletin de l’Académie nationale de médecine, Paris, 1923, 89: 37. Journal de médecine de Paris, 1923, 43: 235-237
- ^ "Noel Rosa 100 anos". O Página Cultural. Archived from the original on April 2, 2015. Retrieved March 1, 2015.
- JSTOR 3513674.
Handžić-Ćuk, J., Ćuk, V., Rišavi, R., Katić, V., Katušić, D., Bagatin, M., ... Gortan, D. (2007, June 29). Pierre Robin syndrome: characteristics of hearing loss, effect of age on hearing level and possibilities in therapy planning: The Journal of Laryngology & Otology. Retrieved from https://www.cambridge.org/core/journals/journal-of-laryngology-and-otology/article/pierre-robin-syndrome-characteristics-of-hearing-loss-effect-of-age-on-hearing-level-and-possibilities-in-therapy-planning/6DD871B7BD583AD124C1EE0A3538FCCD
Handzic, J., Bagatin, M., & Subotic, R. (1995, February). Hearing Levels in Pierre Robin Syndrome. Retrieved March 11, 2020, from https://www.researchgate.net/publication/15470673_Hearing_Levels_in_Pierre_Robin_Syndrome
Pierre Robin Syndrome - Birth Defect Fact Sheet. (2020, March 11). Retrieved from https://www.birthdefects.org/pierre-robin-syndrome
Pierre Robin Sequence (PRS). (2020). Retrieved from http://craniofacialteamtexas.com/pierre-robin-sequence-prs/