29. Craniofacial Clefts
- Plato said that matter is a geometrical expression of space.
- Faraday, in fact a book binder by profession and later a physicist remarked that space was too wonderful a thing to be empty and described energy fields within them.
- Einstein showed that these fields were not only dynamic in relation to each other but the energy within them was the progenitor of matter.
- Higgs conceptualized the first bit of matter, now proved in the tunnels of Switzerland and this matter was called a Boson because Bose in his mind created the mathematical basis for this occurrence which Einstein had endorsed. Bose and Einstein were contemporaries.
- In the Geeta the body is called the field (kshetra) and it is averred that the one who knows the field is the knower (kshetradnya, dn, gn, gnosis to know). This idea was put forward by a sage called Kapil.
- It so happens that this theory fits the three dimensional development of the craniofacial region in which fields grow independently and then aggregate. This development is programmed by the genes (the knower of point 5 above), and occurs between the fourth and the eighth week of gestation which is the fourth dimension, that of time.
- Either when fields are deficient or they do not aggregate according to the pre-determined genetic plan or when the fields are dysplastic, a congenital malformation results (a cleft or an abnormality of volume or dystopia).
- This three dimensional development of the ecto-mesenchyme also encloses spaces which are lined by the entoderm (the mouth, the nose, the pharynx and the cranial cavity) (please see Dr. Suramani’s work at the end of this chapter). To begin with the spaces are in continuity but get sealed off in the normal course. If the sealing process fails a cleft results for e.g. a craniopharyngeal cleft with or without herniation of the intra-cranial contents.
- In addition to an inherently abnormal genetic pattern the genetic motivation can also be altered by way of a genetic mutation caused by environmental factors. Abnormalities can also occur in the craniofacial region by purely mechanical factors such as amniotic bands.
- What matters on the ground is proper growth of cells and their timely migration and interaction followed by aggregation. As the events unfold, equally crucial is apoptosis, the normal programmed death of a certain number of cells. In the absence of apoptosis the resultant dysplastic event is likely to cause formation of excess tissue.
- A bare minimum of five field areas in the craniofacial region need to be understood by a practicing plastic surgeon. Of these five, three migrate and grow from the lateral side viz. themandibular and the maxillary which are easy to understand and are usually known. The third is the optic vesicle which to begin with is both more cranial and lateral. Development of the eye has its own independent course but as it migrates medially it is enclosed in a bony cavity which in part arises from the maxillary field. Therefore clefts in the region can affect the orbit and its surroundings (of ecto-mesenchymal origin) e.g. eyelids but not the eye itself which will be abnormal only when the optic vesicle is abnormal (micro-ophthalmia, anophthalmia). The other two fields are the median field from which forms the filtrum and the nasal septum as also the ethmoids. The fifth field is the lateral nasal or the fronto nasal field from which form for e.g. the nasal bones and the forehead. The last two the median and the fronto-nasal mainly migrate caudally but also grow laterally to join the mandibular and maxillary fields to complete the jig-saw.
- This development also goes by the name of neuromeric developmental theory because of the well substantiated assumption that the events in the cranio-facial region are controlled by the development of the neural tissue which is growing pari-passu. Lack of development of the fore-brain for e.g., by whatever cause will not allow the development of the fronto-nasal process and can lead to an anencephalic skull in the anterior region (probably not compatible with life). Though named holoprosencephaly this event is in fact an extreme form of a cleft caused by agenesis.
- Reproduced below are diagrams to show how and where craniofacial clefts can occur and their numbers as given by Tessier who originally classified these clefts. The figures to the left are drawn on a dry skull by way of Photoshop. These clefts transcend all three layers of embryological development i.e. ecto, meso and entoderm and occur with varying degrees of severity and may be unilateral or bilateral or may also present as syndromes; for example, Treacher Collins’ Syndrome (please see chapter 26, paragraph 2) where deficiencies are restricted to the mesoderm with secondary changes in the other two layers. The subject of syndromes is covered later in these short notes.
Modified drawings from The Atlas of Craniomaxillofacial Surgery by messers Jackson, Munroe, Salyer and Whitaker (Mosby, 1982) and the numbers of clefts are marked on the skull and later depicted by photoshopping the figure of the skull.
Prof. Ramesh Sharma, Chandigarh, adds his understanding of the Tessier classification with the help of following diagrams which are numbered according to the cleft.
A note from Dr. Subramani from Bangalore, edited by Ravin Thatte, the compiler of these short notes is reproduced below.
“The well known classification of craniofacial clefts by Tessier is based on embryology but is restricted to the anterior cranium and the whole of the face up to the mandible. Our classification is different. We hope to call it the “Bangalore” classification and it extends the embryological boundaries to the vault as well as the occiput and also the back (the notocordal element) and includes the neck in front because all these parts develop in the same embryological space. The mandibular and the maxillary arches for example are closely associated with the pharyngeal arches which are related to the neck and these pharyngeal arches, when they get invaginated by the entoderm, form important constituents of the hollow parts of the face and the neck. Some of these linger on as sinuses (e.g. branchial sinus with tracts leading up to the tonsil). We have therefore made a comprehensive new classification of craniofacial clefts in which we have deviated from the Tessier classification by putting the oral cavity as the central point from which clefts radiate. It so happens that in our collection of 147 plus cases the majority did occur around the oral cavity. It is true that clefts 9, 10 and 11 as per the Tessier classification do not regularly involve the tissue around the oral cavity. But a wider scrutiny of many of these cases have evidence of Tessier clefts 3, 4 and 5 and line drawings in the atlas of Cranio-maxillofacial surgery by M/s Jackson, Munroe, Salyer and Whitaker (Mosby, 1982) bears testimony to this inference. What are called in general parlance as clefts of the lip and palate do not strictly fall in this classification because they constitute facial clefts and occur following local causes and are usually called anomalies.”
Dr. Subramani has his own classification of clefts (the Bangalore classification) which is more exhaustive and includes the posterior part of the skull as well as the front and the back of the neck and in fact the classification extends to the cervical and upper dorsal spine. A pictorial description of the classification follows.
Dr. Subramani’s Bangalore classification as mentioned earlier also encompasses the vault, the occiput as well as the cervical and the upper dorsal spine. Since these conditions are more often than not treated by spinal or neurosurgeons, only figures are reproduced without any legends at the bottom but the description within the figure has been retained. This has been downloaded from The July-December 2005 Vol. 38, Issue 2 of the Indian Journal of Plastic Surgery (editor MR Thatte). All further clarification of Subramani’s classification can be obtained from him personally (email: email@example.com).
Please note that Dr. Subramani’s classification begins with the number 1 because he states that 0 is an idea and not a number.