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Craniosynostosis for orthodontist by almuzian

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Craniosynostosis for orthodontist by almuzian

  1. 1. Craniosynostosis Definition 1. A syndrome is the association of severalclinically recognizable signs and symptoms, which can occur together in an affected individual. A large number of syndromic conditions involve the craniofacial region (Gorlin et al, 2001). 2. Abnormal growth pattern of the skull o skull cannot expand perpendicular to the fused suture o compensates by growing more in the direction perpendicular to the open sutures (Virchow’s Law= Virchow'sLaw,duringcraniosynostosis,skull growthis restrictedtoa plane perpendiculartothe affected,prematurelyfusedsutureandis enhancedina plane parallel toit.) o growth pattern provides the necessary space for the growing brain, but results in an abnormal head shape and facial features Classification according to mode of inheritance 1. Familial syndrome: Those that occur as part of a characterized Mendelian disorder, resulting from a single gene defect: • Autosomal dominant • Autosomal recessive; • X-linked dominant • X-linked recessive 2. Sporadic syndrome: Those arising from structural abnormalities of the chromosomes; due to teratogenic agents like: • Teratogen: eg Drugs (alcohol, phenytoin, thalidomide); Physical agents (radiation, intrauterine mechanical restraint). • Maternal illness: eg Infections (cytomegalovirus, rubella, syphilis); • Nutritional 3. Idiopathic Classification according to clinical features I. Craniosynostoses • Isolated craniosynostosis 70% • Syndromic craniosynostosis a. Apert's syndrome b. Crouzon's syndrome
  2. 2. c. Pfeiffer syndrome II. Orofacial clefting syndromes • Cleft lip and palate • Pierre-Robin syndrome III. Brachial arch disorders • Craniofacial microsomia • Auriclo-oclu -vertebral syndrom (Goldenhar syndrome) • Di George's syndrome • Mandibulofacial dysplasia (Treacher Collins syndrome) • Oro-facial-digital syndrome IV. Syndromes affecting bone / cartilage • Achondroplasia • Cleido-cranial dysplasia V. Neural tube defect • Anencephaly • Encephaloceles • Holoproscencephaly • Hydrocephaly • Foetal alcohol syndrome (FAS) • Binder's syndromes (maxillonasal dysplasia) • Spina bifida Craniosynostosis The craniosynostoses are a heterogenous group of disorders characterized by premature fusion of the cranial sutures. This can occur in isolation or in association with other anomalies (17%), in a number of well-characterized syndromes. CRANIAL ANATOMY The newborn infant's skull is composed of bony plates separated by sutures. This arrangement accommodates transient skull distortion during birth and permits future growth of the brain, the volume of which quadruples during the first two years of life. There are four major sutures: the metopic, coronal, sagittal, and lambdoid. Three additional sutures that contribute to calvarial development are considered minor: the frontonasal, temporosquamosal, and frontosphenoidal. The sagittal, coronal, and metopic sutures meet at
  3. 3. the anterior of the skull to form the anterior fontanelle, palpable just behind the forehead at the midline. The posterior fontanelle is formed by the intersection of the sagittal and lambdoid sutures Aetiology Syndromic Craniosynostosis - Genetic mutations  Fibroblast Growth Factor Receptor FGFR 1, 2,3 and TWIST genes  FGFR 2 90% of the syndromic craniosynostoses (Apert, Crouzon, Peiffer)  The mutations can be divided into mutations that lead to; o Gain of function (in FGFR genes) o Loss of function (in TWIST genes) 2° effects on ↓FGFR function Nonsyndromic Craniosynostosis - greatly unknown hypotheses are; 1. Biomechanical factors Fetal head constraint during pregnancy ↓expression of Indian Hedgehog protein and noggin = factors influencing bone development. 2. Teratogens (Environmental factors)  Maternal smoking  Maternal exposure to amine-containing drugs. 3. Maternal illness (Hormonal factors) Hyperthyroid induced craniosynostosis - bone matures faster due to high levels of thyroid hormone 4. Genetic factors o In 6 - 11% (bilateral >unilateral) familyhistory o FGFR3 - 31% of the caseswithnonsyndromiccoronal synostosis Diagnosis The diagnosis in cases of syndromic craniosynostosis may require  phenotypic assessment  radiologic (computed tomographic scan)  genotypic (chromosomal and molecular) investigations, Craniosynostosis may be classified according to  the number of involved sutures (single or multiple),  location (sagittal, metopic, unilateral or bilateral coronal, lambdoid, or minor sutures),  as an isolated event (nonsyndromic, simple) Affect FGFR Genes
  4. 4. Isolated craniosynostosis  Several additional hypotheses regarding the mechanisms underlying premature closure of cranial sutures in nonsyndromic craniosynostosis have been proposed 1. Systemic factors I. Craniosynostosis is associated with endocrine abnormalities, such as hyperthyroidism, and warfarin or valproate use during pregnancy [7,8]. II. There is an increased incidence of isolated craniosynostosis in multiple pregnancies and in the presence of uterine abnormalities, such as bicornuate uterus, implying that compression of the fetal skull during pregnancy can contribute to craniosynostosis. III. Mutations in fibroblast growth factor receptor (FGFR) family [10] may also be found in patients with nonsyndromic craniosynostosis. 2. Local factors I. According to Moss's dural hypothesis, abnormal dural attachments exert restrictive tensile forces that arrest bone growth and lead to premature suture closure II. alternative theory is that an intrinsic abnormality in the cranial suture cells. produces early fusion. These cells demonstrate prolonged doubling time and are inhibited by exposure to osteoblast growth factor  Around 1 : 2,000 children are born with premature fusion of a cranial suture  These cases usually occur sporadically but can also be familial  Fibroblast growth factor receptor (FGFR) and TWIST mutations are the most commonly associated with Craniosynostosis syndromes.  Most commonly the sagittal; but the coronal, metopic (frontonasal suture) and lambdoid sutures can also be affected.  The craniofacial features are dependent upon which suture is affected but usually involve distortion of the skull due to excessive compensatory growth in unaffected regions. Examples include: I. True craniocynostosis A. trigonocephaly (fusion of the metopic suture), B. Brachycephaly (fusion of the coronal suture and lambdoid suture bilaterally) C. Dolichocephaly or Scaphocephaly (fusion of the sagittal suture),
  5. 5. D. Plagiocephaly (fusion of coronal and lambdoidal sutures unilaterally), Lambdoid synostosis was a focus of interest after the impact of the Back to Sleep campaign (supine sleeping is better than prone sleep as it has less effect on cranium, less SID and longer stage 3 Non-REM and shorter REM which all good) initiated by the American Academy of Pediatrics in 1994 resulted in an epidemic of infants with posterior plagiocephaly. E. Oxycephaly conical or pointed skull, delayed onset bilateral coronal synostosis. II. Deformational Plagiocephaly o No fusionof the sutures o Skull changesshape due toextrinsicforces o No bulgingof the mastoid o Skull base notaffected o Positionof the earsislevel anddisplacementof one earto the frontis characteristic for deformational plagiocephaly. III. Primary microcephaly o Absence of growthof the brain → renderingthe suturesof the cranial vaultuseless → the suturesclose o Pansynostosislike image. o Differentiationbetweenthesetwoconditionscanbe made witha computed tomography(CT) scan. o
  6. 6. Medical history  Risk factors during pregnancy  Familial rate  Presence of symptoms of elevated intracranial pressure (ICP). Physical examination  Fundoscopy → papilledema (optic disc swelling 2° to ↑ICP)  Measurement of the head circumference + growth curve  Assess skull deformity Supplemental analysis  3D CT - gold standard for diagnosing craniosynostosis  Allows for surgical planning and 3D reconstruction/stereolithographic modeling as required  MRI scans  Genetic testing Apert's syndrome Aetiology: • acrocephalopolysyndactyly type I (typoe II and III are below) • Autosomal dominant • It is due to paternal mutation • Defect in the FGF receptor 2 gene • Prevalence of the disease (1 in 100,000) Extraoral sign and symptoms • Premature fusion of the coronal and frontosphenoidal sutures and the sphenoethmoidal synchondrosis  Syndactyly of hand and feet (soft tissue and bone). Syndactylyof the handsand feet= Failure of programmedcell deathorapoptosiswhichnormallycausesseparationof the digits→ skin,and rarelybone,betweenthe fingersandtoesfuses.Especiallymediatedgreat toesand thumbs. Fusionof fingersortoeswithanequal numberonbothsidesof the body.(symmetrical).Itistypical forthe middle 3fingerstobe fusedtogether.The thumband bigtoe maybe broadand malformed.Abnormalshortnessiscalledbrachydactyly. Cohen (1984) Classification I. Type 1: thumband little fingernotfused II. Tpye 2: onlythumbisfree III. Type 3: all fused
  7. 7. • Exophthalmos is always present, largely because of orbital hypoplasia with retruded supraorbital, infraorbital, and lateral orbital rims. • The widened cranial base can result in hypertelorism. orbital dystopia and develop optic atrophy • Proptosis • Midface hypoplasia • Maxillary hypoplasia • Class III malocclusion • Mental retardation more common than in Crouzon syndrome • Hearing loss common • Cardiovascular/genitourinary anomalies w10% • Cervical spine anomalies (C5 and C6 fusion) common Intraoral sign and symptoms • High arched and narrow palate • CLP • Bulbous lateral palatal swellings – containing hyaluronic acid • AOB • Crowding • micro and hypodontia • Delayed eruption Crouzon's syndrome • It is due to paternal mutation of fibroblast growth factor receptor 3 (FGFR3) • Prevalence 1.6:100,000 • Premature fusion of the coronal and frontosphenoidal sutures and the sphenoethmoidal synchondrosis • Other same as Apert • Differential diagnosis - Aperts has syndactyly • Normal IQ and limbs • Less neuro deficit & less incidence of CP
  8. 8. Pfeiffer syndrome • Prevalence 1.6:100,000 • It is due to paternal mutation of fibroblast growth factor receptor 1 (FGFR1) • Premature fusion of the coronal and frontosphenoidal sutures and the sphenoethmoidal synchondrosis • Similar to Apert in addition, the syndrome includes abnormalities of the hands (such as wide and deviated thumbs) and feet (such as wide and deviated big toes). • Skeletal (eg, radiohumeral synostosis of the elbow), central nervous system (CNS; eg, hydrocephalus), and gastrointestinal abnormalities (eg, imperforate anus) also frequently occur [44]. • The most widely accepted clinical classification of Pfeiffer syndrome was published by M. Michael Cohen in 1993 by broad thumbs, broad great toes, brachydactyly, and possibly syndactyly:[3] I. Type 1, also known as classic Pfeiffer syndrome, includes craniosynostosis and "midface deficiency." This type is inherited in an autosomal dominant pattern. Most individuals with type 1 Pfeiffer syndrome have normal intelligence and a normal life span. II. Type 2 includes a cloverleaf-shaped skull (Kleeblattschädel) due to extensive fusion of bones, as well as severe proptosis. This type occurs sporadically (i.e., does not appear to be inherited) and has "a poor prognosis and severe neurological compromise, generally with early death." III. Type 3 includes craniosynostosis and severe proptosis. This type occurs sporadically (i.e., does not appear to be inherited) and has "a poor prognosis and severe neurological compromise, generally with early death." Carpenter syndrome  Carpenter syndrome, also known as acrocephalopolysyndactyly type II  It is associated with mutations in RAB23 (RAS-associated protein), a guanosine triphosphate hydrolase (GTPase) involved in intracellular membrane trafficking regulation  Similar to Apert but with concurrent coronal, sagittal, and lambdoid craniosynostosis [50] and hypoplastic mandible and/or maxilla and poludyctyle
  9. 9. Saethre-Chotzen Syndrome  Saethre-Chotzen syndrome, also known as acrocephalosyndactyly type III (MIM #101400), is an autosomal dominant disorder [51]. Mutations in the TWIST gene, which is located on chromosome 7p21.1  Patients affected by Saethre-Chotzen syndrome typically have craniosynostosis of coronal, lambdoid, and/or metopic sutures  The characteristic facial appearance includes a towering (turricephalic) forehead, low-set hairline, facial asymmetry with septal deviation, and ptosis of the upper eyelids [57,58].  Cutaneous syndactyly, usually partial, frequently occurs and involves the second and third fingers and/or the third and fourth toes [44]. Most patients have normal intelligence. Treatment considerations in craniosynostosis syndromes Vargervik et al 2012 The interdisciplinary teams can be comprised of professionals from the fol-lowing disciplines:  Craniofacial surgery,  Hand surgery,  Neurosurgery,  Ophthalmology,  Oral and maxillofacial surgery,  Orthodontics,  Otolaryngology,  Pediatrics
  10. 10.  Pediatric dentistry,  Prosthodontics,  Psychology,  Radiology,  Social work,  Anesthesiology,  Genetics,  Intensive care,  Nursing,  Speech and language pathology. I. Airway and feeding Obstructive sleep apnea is common due to: • Midface deficiency, • Choanal stenosis or atresia, • Long thick velum, • Laryngotracheal anomalies, • Central apneas Management • As lymphoid tissue reaches its peak size tonsillectomy or adenoidectomy may not be indicated. • Nasopharyngeal tubes • Continuous positive airway pressure • Tracheostomy are sometimes required. • Midfacial advancement may prove helpful for children and adolescents. • Assessment for central apnea begins in infancy; reassessment frequency is determined by diagnosis and individual features.
  11. 11. II. Central nervous system Increased intracranial pressure (ICP) is a concern whenever sutures fuse prematurely Signs and symptoms of increased ICP include • a bulging fontanelle • radiographic beaten copper skull appearance • headaches, • nausea • vomiting, • irritability; • diagnosis can be challenging, especially in the very young Management • a ventriculoperitoneal shunt, • endoscopic third ventriculostomy, • early/repeat cranial decompression. III. Other systems • Exophthalmos increases risk for corneal abrasion, exposure keratitis, and globe trauma. Ocular lubrication, tarsorrhaphy, or early fronto-orbital advancement are strategies to protect the globes. • Patients require regular evaluation for middle ear disorders and hearing loss, which are common. • Timing of cleft palate repair depends on speech acquisition; it may be delayed relative to routine cleft management. • Dental development should be monitored by a pediatric dentist and an orthodontist. • Limb anomalies are managed by pediatric orthopedists. • Visceral anomalies are managed by the appropriate specialists. • Genetic evaluation and counselling are crucial. • The potential psychosocial and educational impact of these conditions necessitates ongoing monitoring by a trained psychiatrist or psychologist. IV. Dental, orthodontic and craniofacial surgery
  12. 12. The roles of orthodontist are:  Coordinate dental care across primary and secondary care as needed  Review the development and eruption of the dentition and establishment of the occlusion from birth onwards  Provide or oversee orthodontic treatment to: align the dentition, create interdental space for osteotomies and prepare for orthognathic surgery A stagedapproach 1. 1st -2nd year of life:  Baseline diagnostic records (eg, full head CT scans; cephalograms; intraoral, facial, and head photographs)  Fronto-orbital advancement, involving fused suture release,  anterior vault and orbital expansion,  forehead and orbital bandeau reshaping, is typically performed in the first year of life.  Posterior vault expansion  Caries risk assessment  Anticipatory guidance or counseling (oral hygiene, dietary, injury prevention, non-nutritive habits)  Fluoride supplementation assessment  Dental prophylaxis and topical fluoride  Monitor craniofacial growth and development, including the deciduous dentition 2. Mixed dentition:  Baseline diagnostic records (eg, full head CT scans; cephalograms; intraoral, facial, and head photographs)  Midfacial advancement to address orbital and zygomatic deformities is performed in early childhood (after 5e7 years of age), at which time the cranial vault and orbits approximate 90% of adult size. Midfacial advancement techniques include: http://download.lww.com/wolterskluwer_vitalstream_com/PermaLink/PRS/A/PRS_131_1_2 012_11_29_FORREST_205023_SDC2.flv.html a. Monobloc advancement, this is indicated only if at least 3 of the following are
  13. 13. present:  increased ICP  risk of ocular damage  respiratory problem  speech  aesthetic  occlusion b. facial bipartition,  The facial bipartition. Moving the orbits into the correct position results in a transverse expansion of upper dental arch and creates midline diastema the size of which is determined by the amount of orbital movement and the point of rotation.  For the FFA mortality rates as high as 4.5% have been reported mainly due to CS fluid leakage, bleeding or infection. c. subcranial Le Fort III osteotomy; a technique is selected based on the individual patient’s situation.  Caries risk assessment  Periodontal disease assessment  Anticipatory guidance or counseling (oral hygiene, dietary, injury prevention, nonnutritive habits)  Fluoride supplementation assessment  Dental prophylaxis and topical fluoride Evaluation of molar positions before surgical procedures and planning with surgeon for the best approach to prevent damage to unerupted teeth  Pit and fissure sealant assessment  Phase 1 orthodontic treatment
  14. 14.  Provide active eruption guidance for permanent teeth that are severely delayed Retention between active orthodontic treatment phases 3. 12-21 years:  Baseline diagnostic records (eg, full head CT scans; cephalograms; intraoral, facial, and head photographs)  Further midfacial advancement and onlay grafting is nearly always required at skeletal maturity  Orthodontic decompensation and orthognathic surgery are then performed.  Esthetic nasal and soft tissue surgery are best delayed until after orthognathic surgery.  Caries risk assessment  Periodontal disease assessment  Fluoride supplementation assessment  Dental prophylaxis and topical fluoride Pit and fissure sealant assessment  Management of dental impactions with surgical exposure and orthodontic assisted eruption  Phase 2 orthodontic treatment

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