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Condylar growth arrest—early versus late treatment
Symposium of Facial Asymmetry 11 The role of interceptive treatment employing condylectomy has been described. Interceptive treatment has been reported where overgrowth has occurred both horizontally and vertically. Recommendations as to the amount of condyle that should be resected vary. Excision of the condyle including a portion of the condylar neck to bring the mandible into the midline of the face has been suggested when treating the adult with condylar hyperplasia/osteochondroma. Does interceptive condylar surgery for the adolescent require excision of a sufficient amount of condyle to bring the mandible to midline? Is high condylectomy a ' better' alternative, relying upon subsequent growth to 'correct' itself? There are no guidelines in the literature to assist the clinician in these decisions. When overgrowth is limited to the horizontal plane, condylectomy for interceptive treatment may be ineffective. In actively growing primates, condylar regeneration has been documented (Sorensen and L a s k i n , 1975). Similarly, the report of A d l e r (1976), relating to Class III adolescent treatment, employing bilateral condylectomies, documents eventual reformation of the condyles within 3-4 years. Thus, if the individual is still growing, following condylar reformation, additional mandibular growth can be anticipated. The concept of high condylectomy for the adolescent with combined horizontal and vertical overgrowth raises the question as to the nature of the growth disturbance. In instances of hemimandibular hyperplasia, the vertical height of the body on the effected side can be viewed as primarily due to compensatory alveolar growth. It does not, however, explain the 'bowing' that is characteristic of the inferior border nor the morphological changes that terminate in the midline of the mandibular symphysis. In contrast, the patient with a hypoplastic condyle has pronounced 'antegonial notching'. Thus, the interrelationship between condylar growth and changes at the inferior border of the mandible are not understood.
Conclusions Hemimandibular hyperplasia, hemimandibular elongation and condylar hyperplasia are reported as a single entity with different manifestations. Characteristics of the 'pure forms', however, distinguish hemimandibular hyperplasia from hemimandibular elongation. Differentiation between condylar hyperplasia with gross enlargement o f the condyle vs. osteochondroma is perhaps the most controversial area. Treatment approaches, however, may be similar. Interceptive surgery appears to be advisable for the adolescent showing combined vertical and horizonal overgrowth. This may allow for 'self correction' or simplify treatment in the future by modifying the unfavourable growth pattern. References Adams, R.: Case history of Mary Keefe, medical section of the
British Association. Bristol Meeting, Sept. 1836, Quoted by Adams, R. (1873) Adler, E. A : Early condylectomyto prevent prognathism: A preliminary report. J. Oral Surg. 34 (1976) 702 Beirne, O. R., D. L. Lake: Technetium 99M pyrophosphate uptake in a case of unilateral condylar hyperplasia. J. Oral Surg. 38 (1980) 385 Cernea, P. : Unilateral hypertrophy of the mandibular condyle. In: E. Husted and E. Hjorting-Hansen (eds.) Oral surgery. Int. Conf., Copenhagen 1967, 255 De Burg, J. E. Norman, D. M. Painter: Hyperplasia of the mandibular condyle. A historical review of important early cases with a presentation and analysis of 12 patients. J. MaxFac. Surg. 8 (1980) 161 Gottlieb, O.." Hyperplasia of the mandibular condyle. J. oral Surg. 9 (1951) 118 Harnpt, G., A. Tasanen, S. Nordling : Surgery in mandibular condylar hyperplasia. J. max-Fac. Surg. 13 (1985) 74 Hovell, J. H. : Condylar hyperplasia. Br. J Oral Surg. 1 (1963) 105 Obwegeser H. L., M. S. Makek : Hemimandibular hyperplasia--Hemimandibular elongation. J. Max-Fat. Surg. 14 (1986) 183 Sorensen, D. C., D. M. Laskin: Facial growth after condylectomy or ostectomy in the mandibular ramus. J. Oral Surg. 33 (1975) 746 Walker, R. V.: Personal Communication
Condylar growth arrest--early versus late treatment J. Bowerman N o r m a n R o w e M a x i l l o f a c i a l Unit, Q u e e n M a r y ' s University H o s p i t a l . L o n d o n , U K
Mandibular growth is a complex multifactorial mechanism; whereas the disciples of the functional matrix theory postulated by M o s s (1968) may question the role of the mandibular condyle as a 'growth centre', the author is of the belief that the mandibular condyle does play an important role in mandibular and facial growth. Acquired condylar growth arrest can occur as a result of trauma, infection, inflammatory diseases and
tumors. The commonest cause is trauma, resulting in ankylosis of the temporomandibular joint and it has been the authors privilege to treat more than a 100 such patients, mainly children from less privileged countries. The ultimate effect of acquired condylar growth arrest depends on the age of onset and whether one condyle or both is involved. In this communication, bilateral condylar growth arrest will not be discussed
12
Journalof Cranio-Maxillo-Facial Surgery
A B C (A) Typical facial asymmetrydue to ankylosis of the right mandibular condylein a child aged 8 years. (B) Result 1 year after one stage reconstruction by costochondral graft and contralateral mandibular osteotomy.(C) Symmetricalfacial appearance at age 17 years, (no further surgical proceduresplanned).
Fig. 1. -
because it does not produce facial asymmetry. Unlike the congenital defect there is no inherent deficiency of associated soft tissue but there is alteration in soft tissue bulk, particularly muscular tissue as a result of disuse and changed action. Interference in condylar growth activity, particularly when due to ankylosis before the age of 5 years, results in severe and progressive facial deformity. Acceleration of the deformity occurs during the growth spurt of puberty and the eruption of the secondary dentition. When the condition is unilateral, dsymmetry of the face is the principle feature due to relative overgrowth of the normal side, the chin becoming deviated towards the affected side. The mandible is short and retruded with decreased vertical ramus height on the affected side, this results in secondary deformity of the maxilla with a tilted transverse occlusal plane. Late treatment
The result of late reconstruction of severe facial asymmetry when growth is complete, is rewarding because of the dramatic improvement in facial appearance which can be achieved. In addition, the normal mechanism of the unaffected temporomandibular joint can be re-educated when mandibular function has been restored but there is always restricted movement in this joint. A one stage surgical procedure is advocated, comprising temporomandibular joint and condyle reconstruction, maxillary osteotomy to correct the occlusal plane, contralateral mandibular osteotomy to facilitate advancement and rotation together with chin augmentation by genioplasty. However, early intervention before facial growth is complete can eliminate the need for such extensive surgery.
Early treatment
The principal procedure is reconstruction of the temporomandibular joint by costochondral graft and associated temporalis muscle pedicle flap and this was reported in a preliminary communication by the author and the criteria for success and the surgical technique was later described (Bowerman, 1976, 1987). In the young child with disease of short duration and minimal asymmetry before development of the secondary dentition, all that may be required is the reconstruction of the temporomandibular joint with restoration of jaw function. Growth at puberty and the eruption of the secondary dentition will then frequently self-correct any residual deformity. In the more advanced condition with marked facial asymmetry, reconstruction of the affected temporomandibular joint, together with a contralateral mandibular osteotomy to facilitate mandibular advancement with rotation and to increase ramus height is invariably required. Subsequent orthodontic control during the eruption of the secondary dentition is desirable to align teeth and obviate maxillary deformity. Results of early restoration of mandibular function and growth can be shown to be significant (Fig. 1A, B, C). Some authors, including Rowe (1983), advocate release of the ankylosis as soon as possible but advise delay in reconstruction of the temporomandibular joint by costochondral graft until the period of maximum facial growth velocity occurs at about the age of 11 years. The author has found that there is no advantage in waiting until this age and it can be a positive disadvantage. Thus, early intervention to reconstruct the temporomandibular joint by costochondral graft is advocated to reduce primary mandibular and secondary facial deformity; improve speech and nutrition; reduce malocclusion and dental
Symposiumof Facial Asymmetry 13 disease and obviate upper respiratory tract obstruct tion in patients with ankylosis. Patients will be shown to illustrate the results of both early and late treatment by one stage total reconstruction. Radiographs will demonstrate reformation of a new functional mandibular condyle as early as nine months after initial reconstruction in the child and the resulting mandibular and facial growth.
References Moss, M. L. : The primacyof functionalmatrices in orofacial
growth. Den Practioner 19 (1968) 65 Bowerman, J. E. : Reconstructionof the TMJ by osteochondral
rib graft,.Abstracts Third CongressEuropeanAssociationfor MaxillofacialSurgery(1976) 33 Bowerman, J. E.: Reconstructionof the temporomandibularjoint for acquired and conjenitalmalformation.Br. J Oral Maxiliofac, Surg. 25 (1987) 14%160 Rowe, N. L: Ankylosisof the temporomandibularjoint. J. Royal College Surg. Edinburgh27 (1983) 209
Contouring of the gonial angle H. Tideman Dept. o f Oral and maxillofacial Surgery, University o f Hong Kong, Hong Kong
The gonial angle is an important part of the profile of the human being, well researched but not well understood. The angular process is a component of the composite mandible which is dependent upon muscle function for development and presumably for its maintenance afterwards. The angle of the jaw appears not only as bone but as an indicator of muscle, motion and way of life and has changed from lower animal, through ancient man, to modern man. A marked gonial angle is present in all terrestrial mammals. During primate evolution, the facial skeleton becomes gradually more bent downwards until, in man, it lies below the overhanging frontal region of the cranium. These changes are associated both with the increasing relative predominance of the brain and a bending of the axis of the cranial base in the region of the pituitary gland. The direction of facial growth throughout the primate series, and especially in man, becomes more vertical. In man the vertical component of facial growth is greater than the forward component. The greatest part of the reduction in size of the jaw bones occurred around the medieval and the 17th Century periods, being closely correlated in time with changes in diet involving the consumption of increasing amounts of refined foodstuffs. The development of the mandible is unusual in that, after the bone has been mapped out in membrane, secondary cartilages appear between the 10th and 14th weeks of the intrauterine life to form the head of the condyle, part of the coronoid process, the mental protuberance and the mandibular angle. Each of these skeletal units is influenced in its growth pattern by a functional matrix that acts upon the bone. The angular process of the human mandible alters its inclination with age, changing from a medial to a lateral flare, during transition from the neonatal to the adult stages. The morphological change in the mandibular angle is shown to be associated with a change in orientation of the masseter muscle. This change to an oblique line of action from the originally vertical one is associated with an increase in the
functional movement of protraction at the temporo mandibular joint. The angle provides attachment for the masseter and medial pterygoid muscles and for the stylomandibular ligament, and has a regional blood supply. The primary blood supply in the region of the angle is derived from the overlying muscles of mastication through the periosteum. In regard to the ramus, the facial and the transverse facial arteries form an arterial plexus within the superficial fibres of the masseter muscle which they supply. The masseteric arterial plexus supplies the coronoid process and the lateral wall of the ramus, The angle forms an integral part of modern analysis of the face and plays a role in the growth prognosis. A large angle indicates more of a tendency to posterior rotation of the mandible, with condylar growth directed posteriorly. A small gonial angle on the other hand indicates vertical growth of the condyles, giving a tendency to anterior rotation with growth of the mandible. The magnitude of the gonial angle seems to be determined by the relation between anterior face height and the length of the ramus. Disharmony between these two dimensions will produce extreme variation in the angle. With a relative increase in anterior face height, the angle will tend to obtuse, as with skeletal open bite, whilst with a relatively small anterior face height, it is more likely to be acute. In syndromes and acquired conditions with excessive growth, such as hemimandibular hyperplasia, or impaired growth such as ankylosis, the features of the gonial angle can differ enormously from the norm. In hemi-mandibular hyperplasia for example, the angle is rounded off and the mandibular lower border is bowed downwards, while in ankylosis the angle is situated at a higher level and the lower border of the mandible is curved to a greater degree than normal, with an antegonial directly in front of the masseter muscle. Changing the angle of the mandible by surgery has been unsatisfactory and controversial, with unstable results in the long-term.
Conclusions Hemimandibular hyperplasia, hemimandibular elongation and condylar hyperplasia are reported as a single entity with different manifestations. Characteristics of the 'pure forms', however, distinguish hemimandibular hyperplasia from hemimandibular elongation. Differentiation between condylar hyperplasia with gross enlargement o f the condyle vs. osteochondroma is perhaps the most controversial area. Treatment approaches, however, may be similar. Interceptive surgery appears to be advisable for the adolescent showing combined vertical and horizonal overgrowth. This may allow for 'self correction' or simplify treatment in the future by modifying the unfavourable growth pattern. References Adams, R.: Case history of Mary Keefe, medical section of the
British Association. Bristol Meeting, Sept. 1836, Quoted by Adams, R. (1873) Adler, E. A : Early condylectomyto prevent prognathism: A preliminary report. J. Oral Surg. 34 (1976) 702 Beirne, O. R., D. L. Lake: Technetium 99M pyrophosphate uptake in a case of unilateral condylar hyperplasia. J. Oral Surg. 38 (1980) 385 Cernea, P. : Unilateral hypertrophy of the mandibular condyle. In: E. Husted and E. Hjorting-Hansen (eds.) Oral surgery. Int. Conf., Copenhagen 1967, 255 De Burg, J. E. Norman, D. M. Painter: Hyperplasia of the mandibular condyle. A historical review of important early cases with a presentation and analysis of 12 patients. J. MaxFac. Surg. 8 (1980) 161 Gottlieb, O.." Hyperplasia of the mandibular condyle. J. oral Surg. 9 (1951) 118 Harnpt, G., A. Tasanen, S. Nordling : Surgery in mandibular condylar hyperplasia. J. max-Fac. Surg. 13 (1985) 74 Hovell, J. H. : Condylar hyperplasia. Br. J Oral Surg. 1 (1963) 105 Obwegeser H. L., M. S. Makek : Hemimandibular hyperplasia--Hemimandibular elongation. J. Max-Fat. Surg. 14 (1986) 183 Sorensen, D. C., D. M. Laskin: Facial growth after condylectomy or ostectomy in the mandibular ramus. J. Oral Surg. 33 (1975) 746 Walker, R. V.: Personal Communication
Condylar growth arrest--early versus late treatment J. Bowerman N o r m a n R o w e M a x i l l o f a c i a l Unit, Q u e e n M a r y ' s University H o s p i t a l . L o n d o n , U K
Mandibular growth is a complex multifactorial mechanism; whereas the disciples of the functional matrix theory postulated by M o s s (1968) may question the role of the mandibular condyle as a 'growth centre', the author is of the belief that the mandibular condyle does play an important role in mandibular and facial growth. Acquired condylar growth arrest can occur as a result of trauma, infection, inflammatory diseases and
tumors. The commonest cause is trauma, resulting in ankylosis of the temporomandibular joint and it has been the authors privilege to treat more than a 100 such patients, mainly children from less privileged countries. The ultimate effect of acquired condylar growth arrest depends on the age of onset and whether one condyle or both is involved. In this communication, bilateral condylar growth arrest will not be discussed
12
Journalof Cranio-Maxillo-Facial Surgery
A B C (A) Typical facial asymmetrydue to ankylosis of the right mandibular condylein a child aged 8 years. (B) Result 1 year after one stage reconstruction by costochondral graft and contralateral mandibular osteotomy.(C) Symmetricalfacial appearance at age 17 years, (no further surgical proceduresplanned).
Fig. 1. -
because it does not produce facial asymmetry. Unlike the congenital defect there is no inherent deficiency of associated soft tissue but there is alteration in soft tissue bulk, particularly muscular tissue as a result of disuse and changed action. Interference in condylar growth activity, particularly when due to ankylosis before the age of 5 years, results in severe and progressive facial deformity. Acceleration of the deformity occurs during the growth spurt of puberty and the eruption of the secondary dentition. When the condition is unilateral, dsymmetry of the face is the principle feature due to relative overgrowth of the normal side, the chin becoming deviated towards the affected side. The mandible is short and retruded with decreased vertical ramus height on the affected side, this results in secondary deformity of the maxilla with a tilted transverse occlusal plane. Late treatment
The result of late reconstruction of severe facial asymmetry when growth is complete, is rewarding because of the dramatic improvement in facial appearance which can be achieved. In addition, the normal mechanism of the unaffected temporomandibular joint can be re-educated when mandibular function has been restored but there is always restricted movement in this joint. A one stage surgical procedure is advocated, comprising temporomandibular joint and condyle reconstruction, maxillary osteotomy to correct the occlusal plane, contralateral mandibular osteotomy to facilitate advancement and rotation together with chin augmentation by genioplasty. However, early intervention before facial growth is complete can eliminate the need for such extensive surgery.
Early treatment
The principal procedure is reconstruction of the temporomandibular joint by costochondral graft and associated temporalis muscle pedicle flap and this was reported in a preliminary communication by the author and the criteria for success and the surgical technique was later described (Bowerman, 1976, 1987). In the young child with disease of short duration and minimal asymmetry before development of the secondary dentition, all that may be required is the reconstruction of the temporomandibular joint with restoration of jaw function. Growth at puberty and the eruption of the secondary dentition will then frequently self-correct any residual deformity. In the more advanced condition with marked facial asymmetry, reconstruction of the affected temporomandibular joint, together with a contralateral mandibular osteotomy to facilitate mandibular advancement with rotation and to increase ramus height is invariably required. Subsequent orthodontic control during the eruption of the secondary dentition is desirable to align teeth and obviate maxillary deformity. Results of early restoration of mandibular function and growth can be shown to be significant (Fig. 1A, B, C). Some authors, including Rowe (1983), advocate release of the ankylosis as soon as possible but advise delay in reconstruction of the temporomandibular joint by costochondral graft until the period of maximum facial growth velocity occurs at about the age of 11 years. The author has found that there is no advantage in waiting until this age and it can be a positive disadvantage. Thus, early intervention to reconstruct the temporomandibular joint by costochondral graft is advocated to reduce primary mandibular and secondary facial deformity; improve speech and nutrition; reduce malocclusion and dental
Symposiumof Facial Asymmetry 13 disease and obviate upper respiratory tract obstruct tion in patients with ankylosis. Patients will be shown to illustrate the results of both early and late treatment by one stage total reconstruction. Radiographs will demonstrate reformation of a new functional mandibular condyle as early as nine months after initial reconstruction in the child and the resulting mandibular and facial growth.
References Moss, M. L. : The primacyof functionalmatrices in orofacial
growth. Den Practioner 19 (1968) 65 Bowerman, J. E. : Reconstructionof the TMJ by osteochondral
rib graft,.Abstracts Third CongressEuropeanAssociationfor MaxillofacialSurgery(1976) 33 Bowerman, J. E.: Reconstructionof the temporomandibularjoint for acquired and conjenitalmalformation.Br. J Oral Maxiliofac, Surg. 25 (1987) 14%160 Rowe, N. L: Ankylosisof the temporomandibularjoint. J. Royal College Surg. Edinburgh27 (1983) 209
Contouring of the gonial angle H. Tideman Dept. o f Oral and maxillofacial Surgery, University o f Hong Kong, Hong Kong
The gonial angle is an important part of the profile of the human being, well researched but not well understood. The angular process is a component of the composite mandible which is dependent upon muscle function for development and presumably for its maintenance afterwards. The angle of the jaw appears not only as bone but as an indicator of muscle, motion and way of life and has changed from lower animal, through ancient man, to modern man. A marked gonial angle is present in all terrestrial mammals. During primate evolution, the facial skeleton becomes gradually more bent downwards until, in man, it lies below the overhanging frontal region of the cranium. These changes are associated both with the increasing relative predominance of the brain and a bending of the axis of the cranial base in the region of the pituitary gland. The direction of facial growth throughout the primate series, and especially in man, becomes more vertical. In man the vertical component of facial growth is greater than the forward component. The greatest part of the reduction in size of the jaw bones occurred around the medieval and the 17th Century periods, being closely correlated in time with changes in diet involving the consumption of increasing amounts of refined foodstuffs. The development of the mandible is unusual in that, after the bone has been mapped out in membrane, secondary cartilages appear between the 10th and 14th weeks of the intrauterine life to form the head of the condyle, part of the coronoid process, the mental protuberance and the mandibular angle. Each of these skeletal units is influenced in its growth pattern by a functional matrix that acts upon the bone. The angular process of the human mandible alters its inclination with age, changing from a medial to a lateral flare, during transition from the neonatal to the adult stages. The morphological change in the mandibular angle is shown to be associated with a change in orientation of the masseter muscle. This change to an oblique line of action from the originally vertical one is associated with an increase in the
functional movement of protraction at the temporo mandibular joint. The angle provides attachment for the masseter and medial pterygoid muscles and for the stylomandibular ligament, and has a regional blood supply. The primary blood supply in the region of the angle is derived from the overlying muscles of mastication through the periosteum. In regard to the ramus, the facial and the transverse facial arteries form an arterial plexus within the superficial fibres of the masseter muscle which they supply. The masseteric arterial plexus supplies the coronoid process and the lateral wall of the ramus, The angle forms an integral part of modern analysis of the face and plays a role in the growth prognosis. A large angle indicates more of a tendency to posterior rotation of the mandible, with condylar growth directed posteriorly. A small gonial angle on the other hand indicates vertical growth of the condyles, giving a tendency to anterior rotation with growth of the mandible. The magnitude of the gonial angle seems to be determined by the relation between anterior face height and the length of the ramus. Disharmony between these two dimensions will produce extreme variation in the angle. With a relative increase in anterior face height, the angle will tend to obtuse, as with skeletal open bite, whilst with a relatively small anterior face height, it is more likely to be acute. In syndromes and acquired conditions with excessive growth, such as hemimandibular hyperplasia, or impaired growth such as ankylosis, the features of the gonial angle can differ enormously from the norm. In hemi-mandibular hyperplasia for example, the angle is rounded off and the mandibular lower border is bowed downwards, while in ankylosis the angle is situated at a higher level and the lower border of the mandible is curved to a greater degree than normal, with an antegonial directly in front of the masseter muscle. Changing the angle of the mandible by surgery has been unsatisfactory and controversial, with unstable results in the long-term.