SURGICAL CORRECTION OF FACIAL DEFORMITY Postgraduate Lecture delivered at the Royal College of Surgeons of England on 25th April 1969 by J. H. Hovell, T.D., F.D.S.R.C.S. St. Thomas's and Royal Dental Hospitals THFE SURGICAL CORRECTION of facial skeletal deformity is a very large subject and in this paper only those deformities which can best be described as excessive degrees of normal variation will be discussed at any length. The majority of these deformities are associated with malocclusion of the teeth and, in fact, it is the variation of the facial skeletal pattern within a 'normal' range which gives rise to many of the malocclusions which are treated by the orthodontist. The orthodontist can alter the facial growth pattern only to a limited extent and this only in the maxilla. Even in the maxilla this can be done only to a small extent and many of the border-line cases at present treated by the orthodontist would be better treated by surgical correction of the underlying skeletal defect. Bilateral abnormalities These comprise all the commoner types of case which need surgery and can be divided into four main groups. Mandibular protrusion. Mandibular retrusion. Maxillary protrusion. Maxillary retrusion. These groups are not mutually exclusive and any two may coexist. The worst deformities occur when a retrusion of one jaw is associated with protrusion of the other, e.g. mandibular prognathism and maxillary retrognathism. Treatment planning In all these deformities it is essential to work out a complete treatment plan taking into account all the morphological and functional abnormal- ities which are present, and thus arriving at a corrected position of the facial skeleton which will not only satisfy aesthetic and functional criteria but will also be stable. Two factors influence stability of the treated case: continued growth of the facial skeleton and the effect of the soft tissue environment. These factors are to a certain extent interdependent and there is in fact a considerable body of opinion that ' growth centres ' are merely areas in which bony growth occurs to keep pace with the development of the associated soft tissues. Certainly traumatic bony morphological abnormalities in children which do not involve soft tissues or growth areas will correct themselves with subsequent growth. Similarly surgical correction of facial skeletal abnormalities in growing children will revert to the 'normal' pattern for the child, to a greater (1970, vol. 46) 92 SURGICAL CORRECTION OF FACIAL DEFORMITY or lesser degree, according to the amount of uncompleted growth at the time of operation. For the same reason any reposition of bony fragments which alters the length of muscles or the direction of muscle pull will be unstable, and in addition to correction of the bony deformity muscle attachments must be repositioned to maintain their correct length and direction of pull. Finally, the investing soft tissues must be adequate to accommodate the repositioned bones, or again relapse will occur. This is readily seen in the correction of receding chins or saddle noses by means of onlay grafts. In the absence of adequate investing tissue bony autografts are resorbed and allelografts are actually pushed back and embedded into the bone behind them if they do not ulcerate through the skin. The position of the teeth themselves, i.e. the form and size of the dental arches, while partly dependent upon the size, form and relationship of the jaws is also determined very considerably by the morphology of the soft tissues. In this respect, from a practical point of view, the tongue is the most important element in the formation of the dental arches, which can be regarded as being moulded around it by the action of the soft tissues of the lips and cheeks. Normally the tongue at rest fills almost the entire oral cavity and if such is the case any procedure which enlarges or diminishes the latter's size will be followed by alteration in the shape of the dental arches and relationship of the teeth, sometimes beneficial, sometimes adverse. From the foregoing statements it is evident that treatment planning in these cases is far from being a matter of bony carpentry. In the early days of this type of surgery many poor results were obtained through disregard of all factors other than skeletal. In dental surgery ortho- dontics is the specialty in which a thorough appreciation of all soft tissue patterning factors is fundamental in treatment. Teamwork between orthodontist and oral surgeon is therefore usual in the assessment of these cases. The application ofthe above principles in treatment planning in the various deformities will now be considered. Mandibular prognathism This is the commonest variation of the facial skeleton which presents for surgical correction. In many other abnormalities the orthodontist by movement of the teeth on the bony bases can produce a stable result which is aesthetically and functionally if not perfect at least acceptable. This is not the case with mandibular prognathism. Apart from aesthetic considerations function may be severely disrupted. The incisor teeth cannot be brought into contact and incision is impossible. In the patient shown in Figure 1 the only teeth to occlude were the lower third molars which met the upper incisors during lateral excursions. Speech also may be affected. In some of these cases there is an associated maxillary retrognathism, which may indeed be the sole cause of the deformity. It would appear to be ideal that in such cases correction of the maxillary 93 J. H. HOVELL deformity should be part of the treatment. For the following reasons this is seldom the case. First, an aesthetically acceptable and functionally excellent result can usually be obtained by mandibular surgery alone. Secondly, the investing soft tissues are inadequate to accommodate a forwardly displaced maxilla and relapse occurs. (This is not the case in facial deformity secondary to craniostenosis, e.g. Crouzon's disease.) /101I

Ib)

(a)

(c)

Fig. 1. Severe case of mandibular prognathism. Pre- and post-operative. (a) Photographs. (b) Models. (c) Radiographs. Gillies reported this many years ago and abandoned the procedure. It is fallacious to think that autogenous bone placed behind the maxilla will prevent this relapse. It will prevent relapse only in the treatment of Crouzon's or similar facial deformities by filling dead space and preventing relapse due to fibrous tissue contraction. Thirdly, a second major pro- cedure is most undesirable. Various techniques have been described for the treatment of this 94 SURGICAL CORRECTION OF FACIAL DEFORMITY abnormality. The two which now gain most general acceptance are those which move back the entire horizontal ramus of the mandible in relation to an undisplaced ascending ramus. These procedures have several considerable advantages. The operative approach is such that the elevator muscles can readily be detached from their mandibular insertions and the pterygo-masseteric sling divided, thus preventing relapse due to adverse muscle pull. These muscles re-attach in the new position of the bone. At the same time that the muscles are detached so also is the deep cervical fascia, which is also divided at the same time as the pterygo-masseteric sling. The deep cervical fascia forms a tense

(a) (b) Fig. 2. Line drawings. (a) Vertical subsigmoid osteotomy for correction of mandibular prognathism. (b) Intra-oral sagittal split for correction of both mandibular prognathism and retrognathism. inelastic sheath around the posterior and inferior borders of the mandible and, unless divided, often forms an insuperable obstacle to backward reposition without tension of the distal fragment of the divided mandible. Backward movement of the entire horizontal ramus moves back all the mandibular attachments of the tongue and floor of the mouth, thus limiting dental relapse due to tongue pressure which is a feature of horizontal ramus ostectomies: also investing tissues readapt more readily with no fear of a 'double chin ' and the intact horizontal ramus forms a better denture base should the patient ultimately become edentulous. Figure 2 illustrates these two techniques. The vertical subsigmoid J. H. HOVELL osteotomy is performed via an extra-oral approach and the sagittal split intra-orally (Obwegeser, 1957). These two techniques are virtually interchangeable and the author has used no other for any case during at least the past three years. Cases occur in which, with only a mild degree of skeletal mandibular prognathism, there is a prognathic relationship of the mandibular to the maxillary dentition due to an abnormal path of closure ofthe mandible secondary to premature dental contacts. This is a very traumatic dental relationship, leading to attrition of the incisor teeth and loosening of these with early loss due to alveolar recession. In children this situation is readily correctible orthondontically, but in adults operative treatment is necessary. This is not surgical correction of the skeletal pattern, which in fact is almost normal, but repositioning of blocks of teeth with their supporting bone. Such segmental surgical movement of teeth is frequently used in conjunction with correction of the skeletal pattern, in order to obtain the best functional occlusal relationship of the teeth. Not only is it used in the correction of severe ' normal ' variations of the facial skeleton, but it is invaluable in the correction of the bony deformities associated with repaired clefts of the lips and palate. Often bony defects are produced in repositioning the segments and these are filled by iliac crest cancellous bone. Mandibular retrognathism or maxillary prognathics While fewer patients with this deformity are referred for its surgical correction, a larger proportion of those who reach the oral surgeon do so because of the traumatic effect of the resultant incisor relationship. In the Class II, Division I incisor relationship with proclined upper incisors, the lower incisors not infrequently traumatize the palatal gingival margin of these teeth with stripping of the gum, alveolar recession and early loss. Orthodontic treatment to retract the incisors, unless accompanied by apical torquLe, will often not abolish this trauma and in the more severe cases sufficient orthodontic distal movement of the upper incisors may be impossible to achieve. In the Class II, Division Il incisor relationship, with retroclined upper incisors and a very deep overbite, not only is the palatal mucosa trauma- tized but also the lower labial mucosa. Again the amount of apical torque needed to correct this condition may not be orthodontically feasible (nor aesthetically desirable). Another feature of the patients referred for surgical treatment is the low Frankfurt mandibular, low gonial angled type of skeletal morphology. These cases not only produce the most traumatic incisor relationship but also are the most difficult to treat orthodontically and the most prone to relapse. This is because the vertical height of the face anteriorly is much reduced, and insufficient bone height is available to accommodate the incisor roots in such position that a normal axial relationship of upper to lower incisors can be achieved. It is not possible orthodontically to 96 SURGICAL CORRECTION OF FACIAL DEFORMITY

(i :f: .. (b

(c) (d)

(e) (f)

(g)

Fig. 3. (a and b) Lateral skull X-ray and photograph showing position of lower incisors which produces trauma to palatal mucosa. (c and d) Photographs showing lateral and full-face views with typical shortening of lower third of face. (e andf) Photographs and (g) X-ray showing aesthetic and occlusal improvement obtained by surgical lengthening of the mandible. 97 J. H. HOVELL alter the vertical height of the face. Surgically, however, this can be done. The supporting bone (alveolar bone) of the teeth is laid down around the teeth as they erupt. As a result, if the vertical height of the anterior part of the lower part of the facial skeleton is increased by surgical alteration of mandibular morphology, the incisor teeth are permitted to erupt further, the bone follows them and their axial inclina- tion can be corrected to give a normal incisor relationship. When, as is frequently the case, the deep overbite is accompanied by over-eruption of the incisor teeth relative to the anterior cheek teeth, surgical correction of the mandibular morphology to produce a normal incisor relationship in a stable position brings the anterior cheek teeth out of occlusion. These teeth will then erupt, alveolar bone following them, to produce normal vertical arch form. Two illustrative cases follow. The first (Fig. 3) is a Class II, Division I malocclusion with trauma to the palate (Fig. 3a and b). The profile and full face pictures (Fig. 3c and d) show the puckering of the lips associated with this shortening of the lower part of the face. Surgical lengthening of the mandible and opening of the gonial angle has corrected the incisor relationship, eliminating the traumatic occlusion, and has also produced a considerable aesthetic improvement.

(a)

Fig. 4. Class II, Division II malocclusion. (a) Models before and after one year of combined orthodontic and surgical treatment. (b) X-ray before treatment showing traumatic incisor relationship. (c) X-ray after orthodontic treatment to procline upper incisors. (d) X-ray after mandibular lengthening. 98 SURGICAL CORRECTION OF FACIAL DEFORMITY Figure 4a shows models of the occlusion in a Class II, Division IL case, and the lateral skull radiograph (Fig. 4b) demonstrates clearly how the lower incisors are biting up into the palate, producing trauma in this region. (This is the reason for the referral of this patient for treatment, not the incisor irregularity.) Preliminary orthodontic treatment is necessary in such cases to procline the upper incisors to a normal axial inclination. This permits lengthening of the mandible and opening of the gonial angle as in a Class II, Division I case. Figure 4c shows a lateral skull X-ray of this patient after ortho- dontic treatment, and Figure 4d one year post-operatively. Patients such as these are by far the most satisfactory to treat as the functional far outweighs the sometimes slight aesthetic improvement which is achieved. When Frankfort-mandibular and gonial angles are high there is plenty of vertical bone available within which the orthodontist can place the incisors into a stable, not traumatic, relationship. Such cases, while not aesthetically perfect, are nevertheless acceptable within the norm of population. There are cases, however, in which the antero-posterior discrepancy between mandible and maxilla is so great that the result of orthodontic treatment is not aesthetically acceptable, and others in which owing to this discrepancy it has failed, or no orthodontic treatment has been undertaken. Figure 5a illustrates such a case, which gives an appearance of mental subnormality and may cause severe psychological trauma to the patient. Whereas the ethics of carrying out fairly major oral surgical procedures purely for minor aesthetic reasons is open in the author's opinion to question, in cases such as this, in which severe deformity is allied to poor function, surgery is far from being purely cosmetic. It must be borne in mind also that these patients if they become edentulous present severe, sometimes insuperable, prosthetic problems, and surgical procedures may be needed at a much less favourable age to enable the fitting of dentures. Early loss of teeth is common owing to poor lip seal and occlusal relationship. In the high or normal gonial angle case it is more common to find that the maxilla is more at fault than the mandible. In planning the correction of this skeletal deformity it is essential first to determine whether mandible or maxilla is at fault. If it is the mandible, then this must be lengthened. If it is the maxilla, then a maxillary ostectomy must be carried out to set back the premaxilla. When, as is more often the case than in mandibular prognathism, both are at fault a compromise of maxillary orthondontics and mandibular surgery may well be desirable. Again this must be a joint decision taken by ortho- dontist and oral surgeon. The method of determining which jaw is at fault is essentially a matter of clinical judgement. Tracings from lateral skull radiographs are used 99 J. H. HOVELL by some orthodontists as a basis for diagnosis and treatment. It is, however, becoming more and more accepted in this country that such an approach is purely mechanistic and that stability of the treated case is dependent entirely upon the position of the crowns of the teeth within their soft tissue environment. The main use of cephalometric surveys is assessment of the changes in tooth position and inclination occurring during treatment, and changes occurring in the facial skeletal pattern with or without orthodontic treatment during the growth period.

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(b)

(a)

Fig. 5. (a) Profile photograph of case of severe mandibular retrognathism. (b and c) Wassmund premaxillary set-back. (b) Removal of buccal bone and access for midline split if necessary. (c) Removal of palatal bone and midline split to permit repositioning of fragments. Similarly it is not possible to tell from lateral skull radiographs which jaw needs correction. For example, the patient shown in Figure 1, although he is obviously clinically flattened in the middle half of the face, had on cephalometric analysis a maxillary protrusion (S.N.A. angle of 920). In the Class II, Division I case it is possible, however, to obtain an accurate picture of the post-operative appearance when the mandible is lengthened by causing the patient to protrude the lower jaw to a normal incisor relationship. If this results in a normal profile, mandibular lengthening is the correct procedure. The production of an unsightly appearance of bimaxillary protrusion points to the need for maxillary surgery. The half-way case may be treated by a combination of ortho- dontics and operation or, if the discrepancy is not too severe, by ortho- dontic means only. The orthodontist, not the oral surgeon, is the right 100 SURGICAL CORRECTION OF FACIAL DEFORMITY person to assess these cases. The author always refers children who may at a later age need operative treatment to an orthodontist for him to treat if possible. In the Class II, Division II case the retroclination of the upper incisors prevents this means of assessment. It is necessary, however, prior to either mandibular or maxillary surgery that the upper incisors should in these cases be in correct axial inclination. Orthodontic treatment is therefore necessary to procline the upper incisors to the required position, subsequent to which assessment can be carried out as in the Class II, Division I case. Mandibular retrognathism As in the correction of mandibular prognathism, many techniques have been used in the treatment of these cases. It has been found that in order to prevent lingual tilting of the lower incisors post-operatively it is necessary to move forward all the mandibular tongue attachments and floor of the mouth, just as it is necessary to move them back in pro- gnathism. This means that the surgical procedure must be behind the mylohyoid ridge. The sagittal splitting operation as used in prognathism, but with the slide in the opposite direction, is ideal for this purpose, and is now the only operation used by the author for mandibular lengthening in this type of case. All other procedures entail the use of autogenous bone grafts in the defect formed. As in prognathism all elevator muscle attachments and deep cervical fascia must be freed. Pre-operative orthodontic treatment is often needed to correct upper incisor inclinations, increase the upper inter-canine width and intrude the lower labial segment. The latter procedure is not infrequently better carried out surgically as a preliminary procedure by setting down the lower labial segment, together with an adequate amount of supporting bone. There is always plenty of bone available between tooth apices and lower border for this to be done in the high gonial angle cases. Maxillary osteotomy This can either be for the correction of maxillary prognathism, maxillary retrognathism or errors in vertical development. Maxillary prognathism Surgically, it would be virtually impossible to set back the entire maxilla. Since, however, the prognathism is largely confined to the tooth-bearing area this portion of the maxilla could be detached and moved distally, removing bone posteriorly. The far simpler procedure first described by Wassmund in 1935 is always used. Essentially it con- sists ofremoving bone from both buccal and palatal aspects of the maxilla, usually in the first premolar region, in correct amount to allow the pre- 101 J. H. HOVELL maxillary segment, after separation from the nasal septum, to be set back as desired. Extraction of teeth must be carried out at the proposed site of bone removal, or pre-existing gaps can be utilized. Ideally the upper incisors should be placed orthodontically in such axial inclination that little maxillary rotation (always palate upwards) is needed, otherwise the bone ends do not meet. A palatal ledge will result and pressure necrosis of overlying mucous membrane may result in an oro-nasal fistula. Accurate pre-operative planning and firm positive post-operative fixation are necessary. Cap splints are undoubtedly ideal for the latter purpose. Two factors must particularly be borne in mind when planning the new position of the upper incisors. The first is their stability in an antero- posterior direction in their new position. The normal position of the upper incisors being produced by them assuming a position of balance between lower lip and tongue, this is the position which must be aimed at, and is always completely back into occlusion with the lower incisors. However aesthetically desirable it may be to bring them only half-way back, if this is done they will not be stable. Either the lower lip will get behind them and push them forward again, or in front of them and pull them right back. The second consideration is maintenance of a correct overbite. Incisor overbite is determined by the angle between the long axes of upper and lower incisors. This should be between 135° and 140° and is not only occlusally but usually aesthetically the best. Since in these cases the lower incisors are already in a position of stability this angle must be achieved by the correct repositioning of the premaxilla. If to obtain it undue anteroposterior rotation of the maxilla is needed, preliminary orthodontic treatment to alter the upper incisor inclinations must be carried out so that the pre-maxilla can be set straight back in order to get good bony apposition. As well as soft tissue morphology, variations of patterns of muscular behaviour may produce alterations in inclination and mal-relationships of the incisors. If these patterns of behaviour are ignored by the surgeon, varying degrees of relapse will occur. This emphasizes the need for orthodontic and surgical co-operation in the diagnosis and treatment planning of these cases. Figure 5b and c shows diagrammatically the operative procedure. It is noted that a midline split of the pre-maxilla permits canine widening without the need for preliminary orthodontic treatment. The blood supply to the maxilla is so good that some Continental surgeons leave it attached by the labio-buccal mucosa only, freeing all other attachments. Personal communications to the author regarding loss of teeth and bone when this has been done have led him always to leave the palatal mucosa intact, in order to preserve extra blood supply to the premaxillary fragment. Using this technique there is no danger of loss of vitality of teeth or bone. 102 SURGICAL CORRECTION OF FACIAL DEFORMITY Although a simpler procedure than mandibular lengthening, because mandibular retrognathism is commoner than maxillary prognathism in adults presenting for surgical treatment, it is less frequently carried out. Also in patients for whom, owing to a low gonial angle and short lower third of the face, orthodontic treatment was impossible or has failed, the same skeletal defect makes it impossible to correct the malocclusion by maxillary surgery alone. It is necessary to lengthen the lower third of the face by mandibular surgery, opening the gonial angle. This also swings the chin distally, which enables the mandible to be lengthened at the same time without producing an unduly prominent chin. Maxillary retrognathism This most commonly occurs as an extreme natural variation of facial skeletal morphology. In these cases it is confined mainly to the lower tooth-bearing area of the maxilla. This can readily be separated from the main body of the maxilla. The bony incision is at a high level, being just below the infra-orbital foramen, and can be made either by bur or chisel. The posterior attachment of this segment to the pterygoid plates is severed by a curved chisel. The equivalent of a le Fort I fracture of the maxilla is thus produced. The detached fragment can then be repositioned in a forward direction and retained in this position until united. Relapse, either total or partial, is unfortunately not uncommon after this procedure and is due to two factors. One is the formation of scar tissue in the dead space which is produced posteriorly. This can be overcome by completely filling this space with iliac crest cancellous bone. The other is inadequate facial soft tissue to accommodate forward positioning of the fragment. If the soft tissues are put under tension, relapse is certain and will occur in spite of bone placed posteriorly, and however long fixation is maintained. Pre-operative assessment of the quantity of soft tissue available to cover the repositioned maxilla without tension is therefore necessary. Brief mention must be made of a similar deformity occurring in clefts of lip and palate. This is always (unless the basic skeletal pattern should also be abnormal) associated with tissue shortage in lip and palate and scar tissue. There is frequently vertical and lateral as well as forward underdevelopment of the maxilla. An Abbe flap to introduce extra tissue into the upper lips is a prerequisite in these cases. In facial deformity due to craniostenosis and some other syndromes the deformity of the upper facial skeleton may not be associated with con- comitant soft tissue underdevelopment. Tessier et al. (1967) have successfully undertaken heroic surgical procedures in these cases, not only to advance the whole of the upper facial skeleton, but also to remove midline ethmoidal bone from the base of the skull downwards, narrowing the intra-ocular width and rotating the orbits medially to correct hypertelorism. 103 J. H. HOVELL Anterior open bite This is the condition in which there is lack of occlusal contact anteriorly extending distally a variable amount. On occasion the only teeth occluding may be upper and lower third molars. This condition may be due to skeletal factors, i.e. very high gonial and Frankfort-mandibular angles and a long lower third of the face. It may be due to soft tissue patterning factors, either morphological or abnormalities of function, or it may be a mixture of the two. Because of the high incidence of soft tissue patterning factors and the difficulty when these are associated with an abnormal skeletal pattern of recognizing their presence (abnormal habit activities of no aetiological significance are often due to this and other malocclusions), surgical treatment of these cases has been followed by an extremely high relapse rate. It is not possible to cover this problem completely in a short review of this nature but a few pointers can be given. 1. A tongue seen on lateral skull X-ray to be filling the entire oral cavity will certainly give trouble. 2. An open bite with a normal or low Frankfort-mandibular angle is unlikely to be of skeletal origin. 3. A severe lisp and proclination of both upper and lower incisors in a case in which the tongue is not filling the entire oral cavitv raises a strong suspicion of primary abnormal tongue activity. Correction of the bony abnormality is a straightforward matter of simple mechanics. There are, however, several procedures which can be used. 1. When tongue activity is normal and size small in relation to the oral cavity. (a) When the open bite extends forward from the last occluding molar tooth. In this case it is usually possible, by dividing the mandible behind the tooth-bearing area, to reposition the entire distal fragment in correct relationship to the maxilla. Minor irregularities of occlusion can be ignored: they will correct themselves post-operatively. The sagittal split is the best procedure for obtaining this result, because not only does it give the maximum area of bony contact between the fragments with no need for grafting, but it also gives the best access for detachment of the lingula. When the front of the distal fragment is raised the back drops down, pivoting on the last molar tooth. This puts the spheno- mandibular ligament on stretch and may prevent repositioning or produce relapse. To divide the spheno-mandibular ligament without damage to mandibular nerve or artery is difficult, but to knock off the lingula via the intra-oral approach is simple. (b) When the open bite is confined to the front of the dental arches. In this case only that part of the jaws carrying teeth which are out of occlusion needs correction. Often in these cases the maxillary teeth as well as the mandibular need repositioning. The K6le procedure (1959) 104 SURGICAL CORRECTION OF FACIAL DEFORMITY is undoubtedly the best (Fig. 6). The faulty lower segment of teeth and supporting bone is elevated to the correct position and the defect produced filled with bone removed from the lower border of the mandible anteriorly. The upper teeth and bone can be similarly replaced and sufficient bone is available for grafting here also. There is no loss of continuity of the mandible. This operation is superior to and is replacing the body osteotomy in which the entire horizontal ramus is divided on both sides. Union is rapid and certain. A graft from the iliac crest is unnecessary. The floor of the mouth is not raised anteriorly and the amount of space available for the tongue is not reduced. 2. When the tongue is large. In these cases the arches are wide, with crenations on the lateral margins of the tongue produced by the teeth. The open bite is almost always confined to the front of the mouth.

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...... '. .. .. (a) (b) Fig. 6. Photographs of anterior open bite corrected by Kole procedure. (a) Pre-operative. (b) Post-operative. The Kole procedure is used here, but there is always some degree of post-operative relapse with proclination of the incisors. A pre-operative tongue reduction, removing tissue both from tip and dorsum, will prevent this relapse. The author prefers to wait until after bony surgery for this, and if relapse commences to carry it out immediately, which reverses the relapse. Unnecessary operations upon the tongue are thus not per- formed. Speech assessed by pre- and post-operative tape recordings is not affected, and in fact with a large tongue may be improved by tongue reduction. 3. When an abnormal pattern of activity with an anterior tongue thrust is present. Bony surgery is as before. Tongue reduction will not alter the activity, but will by shortening it reduce its effect upon the anterior teeth. Only a wedge tip reduction needs to be carried out in these cases. Van Zyle says that division of the genioglossus attachment limits forward thrust of the tongue and will allow an anterior open bite due to tongue thrust to correct itself. Mandibular asymmetries Though not extremes of normal variation these are sufficiently common to merit brief discussion. 105 J. H. HOVELL 1. Unilateral hyperplasia In this condition excessive growth occurs on one side of the mandible. This growth may commence at varying ages. The author has seen onset between the ages of 7 to 35 years. Two main and clearly distinguishable types of deformity are produced. (a) A lateral deviation of the mandible to the normal side with increased prognathism and no increase in the vertical dimension. This is by far the commoner type. (b) Increase in the vertical height of the mandible on the affected side. The condylar neck and ascending ramus are lengthened and the lower border is bowed downwards, losing its normal convexity. Although the symphyseal region of the mandible is tilted, displacing the lower border to the normal side, there is no displacement of the mandible as a whole to this side, and no increase in mandibular prognathism. This type of deformity was present in only 12 per cent of the author's cases. The aetiology of what are probably two separate conditions is not known, although a hereditary factor has occasionally been demonstrated (Hudson, 1968). Treatment is to arrest growth by removal of the condylar growth centre either at once or, if growth is not complete, when the affected side has reached what is estimated to be its ultimate adult length. This operation of high condylar shave (Henny, 1967) has replaced condylec- tomy as it leaves a normally functioning joint. No long-term joint morbidity in patients treated this way has yet been seen. Should excessive growth have already occurred it should first be arrested if, as above, it is continuing, and the asymmetry corrected surgically, should it be sufficiently severe to warrant this, by subsequent operation. 2. Unilateral hypoplasia This is due to damage to the condylar growth centre in infancy or childhood by trauma or infection. It produces shortening of the mandible with deviation to the affected side and mandibular retrognathia. It may be accompanied by partial or complete limitation of movement of the jaw due to fibrous or bony ankylosis of the temporo-mandibular joint. If ankylosis is complete the joint must first be freed at the age of about six years. Should ankylosis be incomplete and some growth still present it may be better to defer correction of the ankylosis. Correction of the asymmetry in these cases should not await cessation of growth. The soft tissue environment and growth is normal and in fact probably fails to carry the mandible forward because of its attach- ment to the base of the skull. There is no compensatory centre at the other end (symphysis) and therefore, in order to prevent the production of secondary deformities of maxilla and soft tissue, the mandible should be lengthened in the ascending ramus during the growth period by grafts, usually from rib. According to the degree of underdevelopment this may need to be done up to three times during the growth period. 106 SURGICAL CORRECTION OF FACIAL DEFORMITY If this is not done the secondary deformities produced may be so severe as to make difficult or even impossible complete correction of the deformity. Unilateral micrognathia associated with the so-called ' first arch dysplasia' is quite different from this. The environment is abnormal and the soft tissues are affected equally with the bone. Maxillary deformity is primary-part of the syndrome-and not secondary to mandibular underdevelopment. Serial bone grafting, if attempted, fails. Grafts resorb and no correction of the asymmetry during the growth period is possible. Masking procedures should be carried out if necessary when growth has ceased. ACKNOWLEDGEMENTS Mr. P. Barton is thanked for permission to copy the line drawings in Figure 5b and c. REFERENCES HENNY, F. (1967) Tomes Lecture (unpublished). HUDSON, A. (1968) Unpublished data. KOLE, H. (1959) Oral Surg. 12. 277, 413, 515. OBWEGESER, H. (1957) Oral Surg. 10, 7. TESSIER, P., GUIOT, G., ROUGERIE, J., DELBET, J. P., and PASTORIZA, J. (1967) Ann. Chir. plast. 12, 103. VAN ZYLE, W. Personal communication. WASSMUND, M. (1935) Lerbuch der Praktischen Chirurgie des Mundes und der Kiefer. Vol. I. Leipzig, Barth. LIVES OF THE FELLOWS OF THE ROYAL COLLEGE OF SURGEONS OF ENGLAND PUBLICATION HAS RECENTLY been announced of the volume of the Lives of the Fellows of the Royal College of Surgeons ofEngland which contains the biographies of Fellows who died between 1951 and 1964. The College now announces that arrangements have been made with S. R. Publishers for assuring a facsimile reprint of the Thelwall Thomas Memorial Plarr's Lives of the Fellows of the Royal College of Surgeons of England, from the two-volume edition revised in 1930 by Sir D'Arcy Power, K.B.E. (Mil.), F.R.C.S.Eng. (Hon. Librarian of the Royal College of Surgeons), with the assistance of W. G. Spencer, O.B.E., M.S., F.R.C.S.Eng., and Professor G. E. Gask, C.M.G., D.S.O., F.R.C.S.Eng. A supplementary edition containing biographies of Fellows from 1930 to 1951 was published in 1953, but the original edition has been out of print since the destruction of the stock during bombing raids on Bristol in 1940. An indication of the scope and importance of this volume can be seen from the following extract from the Preface to the 1930 edition: ' It had long been thought desirable to issue a biographical record of the Fellows of the Royal College of Surgeons of England. In 1912 Sir John Bland-Sutton, Bart., suggested that the work should be under- taken by Mr. Victor G. Plarr, Librarian of the College. Mr. Plarr 107