Postgraduate Medical School, University of London

Transcription

1 THE COMPARATIVE ANATOMY OF CLEFT LIP AND PALATE Part I Classification of Cleft Lip and Palate in Dogs By JAMES CALNAN, F.R.C.S., M.R.C.P. Postgraduate Medical School, University of London IN the veterinary literature there are a few papers on cleft lip and palate but no publication has attempted to define and classify these deformities. In very marked contrast, publications on the condition in humans are commonplace. Yet in order to understand the comparative anatomy of clefts, classification is essential: this has been well shown in man and there is every reason to believe that it will apply equally to animals. The object of this paper is to suggest a classification of cleft lip and palate applied to dogs. Classification of Clefts in Man.--Akhough the first publication drawing attention to the condition was by Roux in 1825, no attempt was made at classification until the earlier part of the present century. Indeed, the realisation that hare lip and cleft palate, occurring alone or together, represent variations of one deformity is of quite recent origin and this is reflected in some of the classifications that have been proposed. In 1923 Brophy suggested that defts could be sorted out into fifteen sub-groups, a somewhat cumbersome classification, although it did include clefts of the lip as well as palate. Veau in 1931 simplified the dassification of deft palate into four groups but failed to provide for lip deformities. Probably the most versatile classification was that of Davis and Ritchie (I922), which proposed three main groups to cover all clefts. The value of this was immediately realised and has become the most widely used classification in this country and is as follows :- Group I. Pre-alveolar clefts (i.e., cleft lip only)-- 2. Midline (rare). Group II. Post-alveolar clefts (i.e., cleft palate only), sub-grouped according to degree as defts of soft palate only (described as 1/3, 2/3, 3/3 as measured from behind forwards) or as clefts of soft and hard palate (the latter being treated in thirds, as for the soft palate). Group III. Alveolar clefts (i.e., clefts of lip, gum, and palate)-- 2. Midline (rare). By making the alveolus the focal point of the classification, " the keystone of the arch," the advantages to surgical treatment became evident. Hence Group I cases could suckle, would not get worse with growth, and technical excellence in 18o

2 THE COMPARATIVE ANATOMY" OF CLEFT LIP AND PALATE I8I repair of the lip was likely to produce a result which was permanent. In Group n cases, repair of the palate before the development of speech appears to increase the chances of obtaining normal speech later, and leaves the patient with no outward sign of deformity. In Group III cases, the problem of treatment is quite different so that even now all are not agreed on the technique of therapy in the bes[ intcrest~ of the growing patient. It is common practice to repair the lip cleft early, at about 2 to 3 months, in order to mould the malposed alveolar elements, and to repair the palate cleft at about I year, as in Group U clefts. Subsequent surgical treatment is usually required either to correct residual deformity of the lip and nose, which was uncorrected by earlier operation, or to correct deformity which becomes evident during growth of the face. The value of a classification in communication should not be underestimated~ and many of the improved results of surgical repair bear mute evidence of this Clearly it is valuable to speak of a Group III I L. patient to a colleague, realising that he has the same exact mental image of the condition, while outlining a method of treatment and the results. More recently, criticism has been levelled at the classification of Davis and Ritchie, because it presents no place for the patient with a cleft lip and alveolus but no cleft palate. To overcome this, Ritchie (1941) suggested that such clefts should form a special sub-group in Group III. Ritchie considered this sub-group relatively unimportant since less than 5 per cent. of all clefts seen would be of this type. From the point of view of treatment these patients present certain unusual problems : frequently there is quite marked deformity of the nostril on the cleft side which is not completely corrected by repair of the lip--and hence the patient differs from Group I cases : also the malposition of the alveolus on the uncleft side is such that there is often insufficient room for it to fit snugly into the correct contour of the alveolar arch--and in this manner the patient differs from Group III cases. As a result some surgeons have classified such patients as Group I cases (with a poor result from the lip repair), while others classified them as Group III cases (with, of course, excellent (normal) speech, because there was no palate cleft, which is usual in this group). Studies by Veau (I937), Stark (1954), and Tondury (1955) indicated that, from the developmental point of view, it was the incisor foramen and not the alveolus which separated lip clefts from palate clefts. Kernahan and Stark (1958), therefore, proposed a classification based on embryological considerations. They classify lip and palate clefts with three groups as before :m Group I. Clefts of primary palate (lip and alveolus only)m ' 2. Medial.,~Total or subtotal. J Group II. Clefts of secondary palate only-- I. Total. 2. Subtotal. 3. Submucous. Group III. Clefts of primary and secondary palates-- 2. Median.,~Total or subtotal. J

3 I82 BRITISH JOURNAL OF PLASTIC SURGERY It will be seen that this classification differs little in its grouping from that of Davis and Ritchie of 1922 ; but it does accommodate the person with cleft lip and alveolus without cleft palate in the group for cleft lip. From the surgical aspect there are two criticisms. As Ritchie has already pointed out, clefts of the lip which involve the gum as far back as the incisor foramen are not common, and certainly not the usual condition. In a survey of 444 primary patients seen in the Nuffield Department of Plastic Surgery at Oxford, Fraser and Calnan (196o) found only eighteen with cleft alveolus without cleft palate of ninety-two Group I cases, an incidence of 19"5 per cent. Yet fundamentally a classification is meant to delineate and sort out the " typical" conditions. Secondly, the terminology is unfortunate because the terms are already used in a different context. In surgical practice, "primary palate" refers to a cleft of the hard and/or soft palate which has not previously been treated--a fresh case--whereas "secondary palate" refers to a patient with a cleft which requires further treatment. In spite of this, there are clearly advantages to be gained by having a surgical classification which can also be used by the embryologist and by the anatomist, at a time when experimental teratology has begun to make great strides towards an explanation for the cause of clefts. Classification of Clefts in Dogs.--Having briefly discussed the classification of clefts in man, the problem of classification of clefts in dogs can be resolved very simply by one question, " similar or dissimilar? " Although clefts in dogs are frequently mirror images of those in the human, important differences do occur. Lip clefts appear usually to involve the alveolus as far as the incisor foramen, in contrast to the human where such is uncommon. The incisor foramen in the dog is large, many times larger than in the human, and as a result of this complete clefts of the hard palate, not involving the gum, appear to end proximally in a gentle sinus and not the more pointed V-shaped termination found in the human. Palate clefts are frequently very wide in dogs, probably because of this, whereas wide horseshoe-shaped clefts in man represent only IO. 4 per cent. of postalveolar clefts. Perhaps the most important difference between the two species lies in the cleft lip cases where an associated cleft of the alveolus is the usual defect in the dog. The classification of cleft lip and palate proposed for dogs can therefore be based on the work of Kernahan and Stark :- Group I. Clefts of lip and gum as far as incisor foramen only-- I. Unilateral, right or left side (Fig. I, A and B). ~Total or 2. Midline. L jsubtotal. 3. Bilateral (Fig. 2, A and B). Group II. Clefts posterior to the incisor foramen-- I. Total (Fig. 3). 2. Subtotal. 3. Submucous. Group III. Clefts of lip, gum, and palate-- I. Unilateral, right or left side (Fig. 4). 2. Midline. it tal or subtotal. Photographs of newborn puppies with clefts are shown to illustrate the various groups.

4 THE COMPARATIVE A ANATOMY CLEFT LIP FIG. I Group I I L. (total). A OF Dachshund, male. AND B PALATE 18 3

5 184 BRITISH JOURNAL OF PLASTIC SURGERY Fro. 3 Group III (total). Pekinese, female. FIG. 4 Group III I L. (total). Bulldog, male. DISCUSSION There is little to add to the classification proposed. Although it is suggested that this method of grouping clefts of the lip and palate applies to dogs, a somewhat limited survey of clefts in other species indicates that it probably covers clefts in all mammals ; that all mammals should develop in a similar manner is not unexpected ; that there should be a universal classification of clefts is a logical sequel. A classification, of itself, is of little practical interest unless it can be put to use in the a~tiology, diagnosis, treatment, or prognosis of this congenital abnormality. Work is progressing along these lines as and when material becomes available. It is a pleasure to record with gratitude the help provided by the many veterinary surgeons, in busy practices, who took the trouble to send me specimens and information. Mr IV. H. Brackenbury is responsible for the excellent photographs. REFERENCES BROPHY, T. W. (1923). " Cleft Lip and Palate." Philadelphia : Blakiston. DAvis, J. S., and RITCHIE, H. P. (I922). ft. Amer. med. Ass., 79, FRASER, G. R., and CALNAN, J. S. (196o). In press. KERNAHAN, D. A., and STARK, R. B. (1958). Plast. reconstr. Surg., 22, 435. RITCHIE, H. P. (1941). Surg. Gynec. Obstet., 73, 645. Roux, P. J. (1825). " Memoire sur la Staphylorraphie ou suture du voile du palms." Paris : Chande. STARK, R. B. (1954). Plast. reconstr. Surg., 13, 20. TONDURY, G. (1955). In " Fortschritte der Kiefer und Gesichts-Chirurgie," vol. I, p. 1. Stuttgart : Thieme. VEAU, V. (193I). " Division Palatine." Paris : Masson. -- (I937). Z. ges. Anat. I. Z. Anat. EntwGesch., Io8, 459.