25. Pathophysiological changes due to (severe) craniofacial anomalies
- At this stage it is necessary to introduce the term ‘craniofacial dysostosis’, also called syndromic craniosynostosis in which sutural abnormalities are widespread including at the cranial base (mainly around the sphenoid) and this is accompanied by maxillofacial dysgenesis which leads to a variety of abnormalities of the face and also include congenital abnormalities in discontinuous parts for e.g. as in the hand as in the Apert’s syndrome. The presence of abnormalities in the limbs (syndactaly of the hand) together with craniofacial synostosis is usually called acrocephalosyndactaly (see under Syndrome in previous chapter).
- The perisphenoidal sutural abnormalities lead to a contracted cranial base. When this is combined with coronal and lambdoid sutural abnormalities the skull fails to grow in the anterio-posterior dimension as well. This causes abnormal temporo-parietal bulging but in addition the brain tends to rise in the vertical direction as it grows mainly in the region of the metopic suture and the anterior fontanelle leading to a tower like appearance and the condition is called turribrachycephaly. This kind of skull is also called a clover leaf skull.
- When this is combined with growth abnormalities of the maxillofacial skeleton (dysgenesis), a variety of changes will be evident from above to downwards.
- A prominent forehead in the upper part but hypoplastic supraorbital ridges.
- Shallow orbits (exorbitism), proptosis and sometimes hypertelorism
- Retruded maxillae
- Underdeveloped mandible
- And the effects on the soft tissue within and around these structures
- This in turn will lead to the following:
- Raised intra-cranial tension
- Corneal exposure in the eye which is proptosed but which is inadequately covered with eyelids which hang from a posterior location
- Narrowed nasopharyngeal space in all dimensions
- And gross occlusal abnormalities which become obvious over a period of years
Note: It also must be noted that the child may have dysmorphism of neuronal tissue and this may also be accompanied by cranio-spinal skeletal abnormalities as well as the Arnold-Chiary syndrome leading to hydrocephalus because of obstruction of the circulation of cerebrospinal fluid at the aqueduct between the ventricles.
- In view of the above,
- Raised intra-cranial tension might need a ventriculo-peritoneal or a ventriculo-venous shunt pending definitive surgery to increase cranial capacity.
- The problems of airway obstruction at the level of the naso-pharyngeal isthmus might be compounded by choanal atresia above and tracheomalacia below and the effects of the airway obstruction appear classically at night when the parapharyngeal muscles tend to relax and act as a passive block. The conditions created are not dissimilar to adult sleep apnoea. There is lack of restful sleep and carboxemia which affects cardiac function and may also lead to neuronal damage. The quality of life during the non-sleeping hours is therefore poor and nutrition suffers. In extreme cases a tracheostomy might require to b performed if relief cannot be obtained by suitable positioning or a nasopharyngeal airway (please see chapter 1, Nature of Plastic Surgery, Life threatening situations).
- The proptotic eyes will sometimes need to be protected with a tarsoraphy if protective spectacles and local lubricants fail to prevent corneal damage.
- Occlusal abnormalities usually follow in older children. In addition to orthodontia individual bones might need to be treated by distraction after a suitable osteotomy, or multiple bone segments might have to be moved en bloc after suitable osteotomies. For example, moving the maxilla and the orbits together will serve a dual purpose, to improve the orbital dimension and location and also correct the maxillary deformity (caused by retrusion) and move the maxillary teeth for better occlusion.
- Children with craniofacial dysostosis undergo treatment for several years because surgery might have to be repeated as the dysgenetic elements both in the cranial and facial components fail to grow like in normal children in spite of surgery. Of these two, the facial component may be operated in later years (for e.g. maxillomandibular deformities). Also, these children might be neuronally deficient, may not have a normal IQ and their appearance attracts unfavourable attention. In the event, not only the children but also their parents need someone to counsel them over the years and therefore any craniofacial team (neuro and plastic surgery, paediatrician, ophthalmologist, ENT surgeon, respiratologist, orthodontist) must also include a sympathetic counselor (preferably a trained psychologist or an empathetic social worker).