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A comparison of two classification systems for hemifacial microsomia
A comparison of two classification systems for hemifacial microsomia R. R. J. Couslcy School of Clinical Dentistry, The Queen’s University of’ Belfast, Northern Ireland
SUMMA
R Y. The classification of hemifacial microsomia (I-IFM) aids in diagnosis, treatment planning, prognostic predictions and data evaluation. The aetiological and phenotypic heterogeneities of HFM, however, make its classification problematic. This study used data from 50 patients to examine the classification of HFM and to compare two systems: OMENS and SAT. The results were concordant with current literature and demonstrated the phenotypic heterogeneity of HFM. Essentially, both classifications embody the major craniofacial defects, but the OMENS system appears to be further refined by its differentiation between soft tissue and nerve defects, and between orbital and mandibular defects. Neither system, however, records deafness or grades auricular tags, although tags occurred in 34% of cases and two patients with otherwise ‘normal’ ears had tags. Therefore, it is suggested that auricular tags be graded as minor ear malformations. Furthermore, the OMENS system could be strengthened by the addition of an asterisk to the acronym in cases with serious non-craniofacial anomalies, for example OMENS*. This adds little complexity to the acronym, but immediately indicates when a patient’s features lie towards the more generalised oculoauriculovertebral end of the phenotypic spectrum.
INTRODUCTION
METHODS
Craniofacial malformations are relatively uncommon, but HFM is perhaps the most significant asymmetrical complex (Poswillo, 1988) its incidence having been estimated at 1 in 5600 live births (Grabb, 1965; Gorlin et al., 1990). HFM displays wide phenotypic variation involving asymmetrical hypoplasia and dysmorphogenesis of the first and second branchial arch derivatives. In particular, mandibular malformation results from hypoplasia of the ramus, condyle, and in sevcrc cases, the temporomandibular joint. Skeletal growth on the less affected side (which is ‘normal’ in 70% of cases) further accentuates the resultant asymmetrical retrognathia and occlusal canting. Other features of HFM include maxillary and zygomatic hypoplasia; external and middle ear malformations; partial paresis of masticatory and facial muscles; and anomalous tooth development. The nomenclature and classifications of HFM have been reviewed by several authors, but remain complex and diverse (Rollnick, 1988; Cohen et al., 1989; Vento et al., 1991). This may add to problems in data evaluation, diagnosis and treatment planning. In an effort to overcome such difficulties, Vento et al. (199 I) introduced the OMENS system as a definitive classification. The aim of the present study was firstly to evaluate a representative sample of HFM cases available in the Australian Craniofacial Unit. This data was then used to assess the OMENS classification, and to compare it to the SAT system devised previously in Adelaide (David et al., 1987).
A total of 50 cases of HFM were chosen at random from 95 such patients referred to the Adelaide unit between 1975 and 1991. It was ensured that complete records were available for the selected cases including notes, clinical photographs (frontal, lateral, chin-up, occlusal views) and radiographs (panoramic, lateral skull, anteroposterior, basal views). Pre- and postoperative three dimensional CT scans were also available for many patients. A variety of significant features was noted for each patient and they were classified according to the OMENS and SAT criteria (listed below). In those patients with bilateral HFM, the two sides were classified separately and included in the results. It is important to note that the patients were graded using pre-treatment records in order to reduce the effects of therapy on the severity (and hence the initial classification) of the condition. SAT classification (David et al., 1987) Skeletal categories: s,: small mandible with normal shape S2: condyle, ramus and sigmoid notch identifiable, but grossly distorted s,: mandible severely malformed, ranging from poorly identifiable ramal components to complete agenesis of the ramus S,: S, mandible plus orbital involvement with gross posterior recession of lateral and inferior orbital rims sg: S, defects plus orbital dystopia and frequently hypoplasia and asymmetry of the neurocranium, with a flat temporal fossa 78
A comparison
Auricle categories: A,: normal A,: small malformed auricle retaining characteristic features A,: rudimentary auricle with a hook at the cranial end correspontiing to the helix A,: malformed lobule with the rest of the pinna absent Tissue (soft) categories: -I-,: minimal contour defect with no cranial nerve involvement T,: moderate defect T,: major defect with obvious facial scoliosis; possibly severe hypoplasia of cranial nerves, the parotid gland, muscles of mastication; eye involvement; a.qd clefts of the face or lips
of two classification
systems
for hemifacial
79
RESULTS The recorded defects and their distribution within each category of the SAT and OMENS classifications are illustrated (Figs 1 & 2). The spectrum of associated anomalies recorded in this sample of 50 HFM cases SKELETAL
DEFECTS
4
CATEGORY 3
OMENS classification (Vent0 et al., 1991) Orbit categories: 0,: normal orbital size and position 0,: abnormal orbil al size 0,: abnormal orbital position (O,, or 0,: depending on horizontal position of orbit relative to less affected side) 0,: abnormal orbir.al size and position
t.
0
I.
10
,.
20
I.
30
I
40
.
.
,
50
60
PERCENTAGE OF AFFECTED SIDES
AURICLE
Mandible categories: MO: normal mandible M,: small mandible and glcnoid fossa with a short ramus M,: short and abnormally shaped ramus (M2, if the glenoid fossa is in a similar position to the opposite TMJ, M2, if the TMJ is inferiorly, medially and anteriorly displaced with a sevcrcly hypoplastic co,ndylc) M,: complete absence of ramus, glenoid fossa and TMJ
microsomia
DEFECTS
3
Ear categories: E,: normal ear E,: mild hypoplasia and cupping with all structures present E,: absence of external auditory canal with variable hypoplasia of the concha E,: malpositioned lobule with absent auricle
PERCENTAGE OF AFFECTU) SDES
TISSUE
DEFECTS
Nerve (VIIth) categories: N,: normal facial nerve N,: upper facial nerve involvement (temporal and zygomatic branches) N,: lower facial nerve involvement (buccal, mandibular and cervical branches) N,: all branches 01‘ the facial nerve affected Soft so: s,: s,: s,:
tissue categories: no obvious soft tissue or muscle deficiency minimal subcc.taneous/muscle deficiency moderate deficiency severe deficiency due to subcutaneous and muscular hypoplasia
0
10 20 30 40 PERCENTAGE OF AFFECTED SIDES
Fig. I - Histograms showing the range of severity defects in 50 patients (53 affected sides) as graded system.
50
of the major by the SAT
80
British
Journal
of Oral
and Maxillofacial ORBIT
Surgery
DEFECTS
MANDIBLE
CATEGWW
2A
0
0 0
10
20
30
PERCENTAGE
40
50
OF AFFECTED
6C
0
SIDES
10
20
10
20
PERCENTAGE
EAR DEFECTS
PERCENTAGE
NERVE
30
40
OF AFFECTED
d
50
SIDES
30
40
OF AFFECTED
(Vllth)
23 a
50
60
SIDLS
DEFECTS
*0
FEFVZENTAGE
SOFT TISSUE
DEFECTS
60 AFFECTED
80
SlDES
DEFECTS
3
2 u\TECXXY 1
0
0
10 PERCENTAGE
Fig. 2 - Histograms
showing
the range
of scvcrity
of the major
defects
is also shown (Fig. 3). The total number of affected sides represented is 53, since three (6”/0) of the cases were bilateral. Overall, 58% of the patients had the right side predominantly affected (54% from unilateral and 4% from bilateral cases). The male: female ratio was 29 : 2 1. No clear genetic history of HFM was substantiated in this sample, although one patient had a brother with facial asymmetry, and one patient and his grandmother both had brachydactyly (an autosomal dominant bilateral thumb anomaly). Facial asymmetry distinguished this phenotype from that of the Nager syndrome. Auricular tags occurred
20 OF AFFECTED
in 50 patients
30
40
SIDES
(53 alfectcd
sides) as graded
by the OMENS
system.
in I7 cases (34%). The tags were multiple in nine such patients and bilateral in three patients (although the major defects were unilaterally distributed). Twice in the case of tags, the ear on the affected side was otherwise normal (AJE,). Three cases suffered a mixed hearing defect, a conductive loss being superimposed unilaterally on a bilateral sensorineural deficit. Hence, normal hearing was present in 34% of the sample. Orbital involvement was seen only in those cases with mandibular malformation and similarly nerve defects did not occur in the absence of soft tissue deficiency.
A comparison
G
70
SC
NUMBEROF 1ATIENl-S
Fig. 3 - Histogram showing some of the associated present in the 50 HFM c~scs studied.
anomalies
DISCUSSIOK The results of this s,rudy are concordant with current literature and demonstrate the phenotypic heterogencity of HFM. Indeed, auriculofacial defects, although being the predominant and pathognomonic features of this condition: are frequently accompanied by a variety of other anomalies (Fig. 3), resulting in further complexity in the task of grading HFM. Any broad classification should embody the major defects, but attempts to include a large number of factors would result in confusion. On review of the literature and their own study of 154 patients, Vcnto et al. (1991) concluded that the fundamental anatomical variables in HFM were the orbit, mandible, external ear. cranial nerves and facial soft tissues. They claimed that the OMENS system is comprehensive, yet Cohen (1991) pointed out that particular specialists may be biased towards other problems, such as cardiac and hearing anomalies. I suggest that the addition of an asterisk to the OMENS acronym would distinguish those cases with serious dcfccts not already covered. This modification is successfully used in other coding systems such as the (CPITN classification of periodontal disease (Ainamo et ul., 1982). For example, if a patient had an extra-craniofacial defect such as a cardiac lesion, he would be graded with an asterisk: OMENS*. This approach adds little complexity to the acronym, but immediately indicates when a patient’s features lie towards the broader oculoauriculovertebral end of the phenotypic spectrum. Does the 0MEN:S system provide any useful information not summa:-ised by other classifications such as the SAT one? Firstly, in common with many other HFM analyses (Longacre et al., 1963; Grabb, 1965; Converse et al.. 1974; Edgerton & Marsh, 1977; Tenconi & Hall, 1983; Murray et al., 1984; Lauritzen et al., 1985; David et al., 1987; Rollnick et al., 1987; Kaban et al., 1988) the mandibular grading is based on Pruzansky’s (1969) original descriptions. The SAT and OMENS systems are also similarly based on
of two
classification
systems
for hcmifacial
microsomia
81
Meurman’s (1957) analysis of ear defects, giving the same grades (Figs 1 & 2). Neither classification, however, has adopted Pruzansky’s modification by including tags as ear anomalies. This is unfortunate since auricular tags may be one of the fundamental markers of HFM. Therefore, the total ear defects in this .study should probably be recorded as 89% (rather than 85%). It is proposed that in future tags be included in the category for minor ear malformation (A,/E,). Vento et al. (1991) chose to distinguish orbital anomalies completely from mandibular defects, with 15% of their cases exhibiting dystopia. In this study, dystopia was present in 43% of affected sides, but the SAT classification of the same data underestimates this by limiting the recording of orbital involvement to the S4 and S, categories (7% of sides). Although there was some disparity between clinical and radiographic dystopia, and orbital anomalies were corrected directly in only a few severe cases, it may still be useful to register dystopia as a measure of skeletal asymmetry. Hence, dystopia may be a secondary defect rather than a primary one. This is in accordance with a recent pathogenic model centred on auriculofacial cartilage deformity (Cousley & Wilson, 1992) and the clinical evidence in both this study and the OMENS one. The SAT soft tissue category has also been split up and modified in the OMENS system. This appears to be helpful since seventh cranial nerve involvement was recorded in 21% of the affected sides. The addition of a So tissue type also refines the classification. Similarly, the addition of a M, grade and the splitting of the M, category into A and R types further clarifies the degree of mandibular deformity. For instance, although mandibular malformation is considered to be the cornerstone of HFM there may bc occasions when it is minimal on the affected side, or more commonly, absent on one side of a bilateral case. These category alterations enable better distinction between the different skeletal and soft tissue deficiency causes of facial scoliosis. which is reflected in subsequent treatment. A classification based on skeletal dysmorphology and its surgical management has been outlined previously (Lauritzcn et al., 1985). Although prognostic and postoperative predictions may be made using this system alone. the broad analytical nature of the OMENS system may improve predictions since it appears to be more sensitive to the wide phenotypic heterogeneity of HFM. Acknowledgements The author thanks Professor Andrew Richardson (Belfast) organisational help, and Mr David J. David, Dr Richard and the rest of the staff and visiting surgeons in Adelaide warmth and assistance during his visit there. He is grateful MIA;BDA Foundation for Elcctivc Awards, the Queen’s sity of Belfast and the Wisdom Dental Student Award for assistance.
for his Harries for their to the Univerfinancial
References Ainamo, J., Barmcs, D., Bcagrie, G., Cutress, T.. Martin, J. & Sardo-Intirri, J. (1982). Development of the World Health
82
British
Journal
Organisation Treatment
of Oral
and Maxillofacial
Surgery
(WHO) Community Periodontal Index of Needs (CPITN). Inrernaiianul Dental Journal.
32.
Cohen, M. M. Jr. (lY91). A critique of the OMENS classification of hemifacial microsomia. Cleft P&/e-Craniofacial Journal, 28, 77. Cohen. M. M. Jr.: Rollnick, B. R. & Kayc, C. 1. (1989). Oculoauriculovertebral spectrum: an updated critique. Cteji Pa&e Journal. 26,276. Convcrsc. J. M., Wood-Smith. D.. McCarthy, J. G., Coccaro, P. J. & Becker. M. I-I. (1974). Bilateral facial microsomia: diagnosis. classification. treatment. Plasric and Reconstrucrive Surgery. 54,413. Cousley. R. R. J. & Wilson, D. J. (1992). Hemifacial microsomia: a developmental consequence of perturbation of the auriculofacial cartilage model. American Journal of’Medicu1 Geneiics, 42,46 I. David. D. J., Mahatumarat, C. & Cootcr, R. D. (1987). Hcmifacial microsomia: a multisystem classification. Plu.sric and Reconsrrucii~e Surgery. 80, 525. Edgcrton, M. T. & Marsh. J. L. (1977). Surgical treatment of hcmifacial microsomia. Plastic und Reconsrrucrive Surgery, SY, 653. Gorlin, R. J.. Cohen. M. M. Jr. & Levin. L. S. (1990). Syzdromes of the Head and ;Veck. 3rd Ed.. t-m . . 641 652. Oxford: Oxford ijniversity Press. Grabb. W. C. (1965). The first and second branchial arch syndrome. Plastic und Reconslrucrive Surgery, 36,485. Kaban, L. B., Moses. M. H. & Mulliken, J. B. (1988). Surgical correction of hemifacial microsomia in the growing child. Plaslic and Reconsrrucrive Surgery, 82, 9. Lauritzen. C.. Munro. I. R. L Ross, R. B. (1985). Classification and treatment of hemifacial microsomia. Scandunavian Journul of Plusric and Reconsrrucrive Surgery. 19, 33. Longacre, J. J.. Dcstefano. G. A. & Holmstrand. K. E. (1963). The surgical management of first and second brdnchial arch syndromes. Plastic and Reconstructive Surgery, 31, 507. .Meurman. Y. (1957). Congenital microtia and mcatal atresia. Archives of Ololuryngolo~y, 66,443.
Murray, J. E., Kaban, L. B. & Mulliken, J. B. (1984). Analysis and treatment of hemifacial microsomia. Plus/it and Recvnsrrucrire Surgery, 74, 186. Poswillo, D. (1988). The actiology and pathogenesis of CrdniOfaCial deformity. Developmenr Supplemenl, 103,207. Pruzansky. S. (1969). Not all dwarfed mandibles are alike Birfh D&q 1, 120. Rollnick, B. R. (1988). Oculoauriculovertcbral anomaly: variability and causal heterogeneity. American Journul of Medico1 Genetics Supplement, 4,41. Rollnick, B. R., Kaye: C. I., Nagatoshi, K.. Hauck. W. & Martin A. 0. (1987). Oculoauriculovertcbral dysplasia and vjariants: phcnotypic characteristics of 294 patients. American Joumul of Medical Genetics, 26,361. Tcnconi, R. & Hall, B. D. (1983). Hemifacial microsomia: phenotypic classification. clinical implications, and genetic aspects. Trealment of Hemifuciul Microsomia. pp 39 49. New York: Alan R Liss. Vento, A. R.. LaBric. R. A. & Mulliken, J. B. (1991). The OMENS classitication of hemifacial microsomia. Cleft PulureCruniojacial Journal, 28,68.
The Author H. R. J. Cousley BSc, BDS School of Clinical Dentistry The Queen’s I!niversity of Belfast Belfast BTl2 6BP Northern Ireland Correspondence and requests for offprints to Mr R.R.J. Cousley, IIousc Surgeon, Department of Oral and Maxillofacial Surgery. St. Thomas’ IIospital, London SEI 7EII Paper received 29 June 1992 Accepted 28 August 1992
SUMMA
R Y. The classification of hemifacial microsomia (I-IFM) aids in diagnosis, treatment planning, prognostic predictions and data evaluation. The aetiological and phenotypic heterogeneities of HFM, however, make its classification problematic. This study used data from 50 patients to examine the classification of HFM and to compare two systems: OMENS and SAT. The results were concordant with current literature and demonstrated the phenotypic heterogeneity of HFM. Essentially, both classifications embody the major craniofacial defects, but the OMENS system appears to be further refined by its differentiation between soft tissue and nerve defects, and between orbital and mandibular defects. Neither system, however, records deafness or grades auricular tags, although tags occurred in 34% of cases and two patients with otherwise ‘normal’ ears had tags. Therefore, it is suggested that auricular tags be graded as minor ear malformations. Furthermore, the OMENS system could be strengthened by the addition of an asterisk to the acronym in cases with serious non-craniofacial anomalies, for example OMENS*. This adds little complexity to the acronym, but immediately indicates when a patient’s features lie towards the more generalised oculoauriculovertebral end of the phenotypic spectrum.
INTRODUCTION
METHODS
Craniofacial malformations are relatively uncommon, but HFM is perhaps the most significant asymmetrical complex (Poswillo, 1988) its incidence having been estimated at 1 in 5600 live births (Grabb, 1965; Gorlin et al., 1990). HFM displays wide phenotypic variation involving asymmetrical hypoplasia and dysmorphogenesis of the first and second branchial arch derivatives. In particular, mandibular malformation results from hypoplasia of the ramus, condyle, and in sevcrc cases, the temporomandibular joint. Skeletal growth on the less affected side (which is ‘normal’ in 70% of cases) further accentuates the resultant asymmetrical retrognathia and occlusal canting. Other features of HFM include maxillary and zygomatic hypoplasia; external and middle ear malformations; partial paresis of masticatory and facial muscles; and anomalous tooth development. The nomenclature and classifications of HFM have been reviewed by several authors, but remain complex and diverse (Rollnick, 1988; Cohen et al., 1989; Vento et al., 1991). This may add to problems in data evaluation, diagnosis and treatment planning. In an effort to overcome such difficulties, Vento et al. (199 I) introduced the OMENS system as a definitive classification. The aim of the present study was firstly to evaluate a representative sample of HFM cases available in the Australian Craniofacial Unit. This data was then used to assess the OMENS classification, and to compare it to the SAT system devised previously in Adelaide (David et al., 1987).
A total of 50 cases of HFM were chosen at random from 95 such patients referred to the Adelaide unit between 1975 and 1991. It was ensured that complete records were available for the selected cases including notes, clinical photographs (frontal, lateral, chin-up, occlusal views) and radiographs (panoramic, lateral skull, anteroposterior, basal views). Pre- and postoperative three dimensional CT scans were also available for many patients. A variety of significant features was noted for each patient and they were classified according to the OMENS and SAT criteria (listed below). In those patients with bilateral HFM, the two sides were classified separately and included in the results. It is important to note that the patients were graded using pre-treatment records in order to reduce the effects of therapy on the severity (and hence the initial classification) of the condition. SAT classification (David et al., 1987) Skeletal categories: s,: small mandible with normal shape S2: condyle, ramus and sigmoid notch identifiable, but grossly distorted s,: mandible severely malformed, ranging from poorly identifiable ramal components to complete agenesis of the ramus S,: S, mandible plus orbital involvement with gross posterior recession of lateral and inferior orbital rims sg: S, defects plus orbital dystopia and frequently hypoplasia and asymmetry of the neurocranium, with a flat temporal fossa 78
A comparison
Auricle categories: A,: normal A,: small malformed auricle retaining characteristic features A,: rudimentary auricle with a hook at the cranial end correspontiing to the helix A,: malformed lobule with the rest of the pinna absent Tissue (soft) categories: -I-,: minimal contour defect with no cranial nerve involvement T,: moderate defect T,: major defect with obvious facial scoliosis; possibly severe hypoplasia of cranial nerves, the parotid gland, muscles of mastication; eye involvement; a.qd clefts of the face or lips
of two classification
systems
for hemifacial
79
RESULTS The recorded defects and their distribution within each category of the SAT and OMENS classifications are illustrated (Figs 1 & 2). The spectrum of associated anomalies recorded in this sample of 50 HFM cases SKELETAL
DEFECTS
4
CATEGORY 3
OMENS classification (Vent0 et al., 1991) Orbit categories: 0,: normal orbital size and position 0,: abnormal orbil al size 0,: abnormal orbital position (O,, or 0,: depending on horizontal position of orbit relative to less affected side) 0,: abnormal orbir.al size and position
t.
0
I.
10
,.
20
I.
30
I
40
.
.
,
50
60
PERCENTAGE OF AFFECTED SIDES
AURICLE
Mandible categories: MO: normal mandible M,: small mandible and glcnoid fossa with a short ramus M,: short and abnormally shaped ramus (M2, if the glenoid fossa is in a similar position to the opposite TMJ, M2, if the TMJ is inferiorly, medially and anteriorly displaced with a sevcrcly hypoplastic co,ndylc) M,: complete absence of ramus, glenoid fossa and TMJ
microsomia
DEFECTS
3
Ear categories: E,: normal ear E,: mild hypoplasia and cupping with all structures present E,: absence of external auditory canal with variable hypoplasia of the concha E,: malpositioned lobule with absent auricle
PERCENTAGE OF AFFECTU) SDES
TISSUE
DEFECTS
Nerve (VIIth) categories: N,: normal facial nerve N,: upper facial nerve involvement (temporal and zygomatic branches) N,: lower facial nerve involvement (buccal, mandibular and cervical branches) N,: all branches 01‘ the facial nerve affected Soft so: s,: s,: s,:
tissue categories: no obvious soft tissue or muscle deficiency minimal subcc.taneous/muscle deficiency moderate deficiency severe deficiency due to subcutaneous and muscular hypoplasia
0
10 20 30 40 PERCENTAGE OF AFFECTED SIDES
Fig. I - Histograms showing the range of severity defects in 50 patients (53 affected sides) as graded system.
50
of the major by the SAT
80
British
Journal
of Oral
and Maxillofacial ORBIT
Surgery
DEFECTS
MANDIBLE
CATEGWW
2A
0
0 0
10
20
30
PERCENTAGE
40
50
OF AFFECTED
6C
0
SIDES
10
20
10
20
PERCENTAGE
EAR DEFECTS
PERCENTAGE
NERVE
30
40
OF AFFECTED
d
50
SIDES
30
40
OF AFFECTED
(Vllth)
23 a
50
60
SIDLS
DEFECTS
*0
FEFVZENTAGE
SOFT TISSUE
DEFECTS
60 AFFECTED
80
SlDES
DEFECTS
3
2 u\TECXXY 1
0
0
10 PERCENTAGE
Fig. 2 - Histograms
showing
the range
of scvcrity
of the major
defects
is also shown (Fig. 3). The total number of affected sides represented is 53, since three (6”/0) of the cases were bilateral. Overall, 58% of the patients had the right side predominantly affected (54% from unilateral and 4% from bilateral cases). The male: female ratio was 29 : 2 1. No clear genetic history of HFM was substantiated in this sample, although one patient had a brother with facial asymmetry, and one patient and his grandmother both had brachydactyly (an autosomal dominant bilateral thumb anomaly). Facial asymmetry distinguished this phenotype from that of the Nager syndrome. Auricular tags occurred
20 OF AFFECTED
in 50 patients
30
40
SIDES
(53 alfectcd
sides) as graded
by the OMENS
system.
in I7 cases (34%). The tags were multiple in nine such patients and bilateral in three patients (although the major defects were unilaterally distributed). Twice in the case of tags, the ear on the affected side was otherwise normal (AJE,). Three cases suffered a mixed hearing defect, a conductive loss being superimposed unilaterally on a bilateral sensorineural deficit. Hence, normal hearing was present in 34% of the sample. Orbital involvement was seen only in those cases with mandibular malformation and similarly nerve defects did not occur in the absence of soft tissue deficiency.
A comparison
G
70
SC
NUMBEROF 1ATIENl-S
Fig. 3 - Histogram showing some of the associated present in the 50 HFM c~scs studied.
anomalies
DISCUSSIOK The results of this s,rudy are concordant with current literature and demonstrate the phenotypic heterogencity of HFM. Indeed, auriculofacial defects, although being the predominant and pathognomonic features of this condition: are frequently accompanied by a variety of other anomalies (Fig. 3), resulting in further complexity in the task of grading HFM. Any broad classification should embody the major defects, but attempts to include a large number of factors would result in confusion. On review of the literature and their own study of 154 patients, Vcnto et al. (1991) concluded that the fundamental anatomical variables in HFM were the orbit, mandible, external ear. cranial nerves and facial soft tissues. They claimed that the OMENS system is comprehensive, yet Cohen (1991) pointed out that particular specialists may be biased towards other problems, such as cardiac and hearing anomalies. I suggest that the addition of an asterisk to the OMENS acronym would distinguish those cases with serious dcfccts not already covered. This modification is successfully used in other coding systems such as the (CPITN classification of periodontal disease (Ainamo et ul., 1982). For example, if a patient had an extra-craniofacial defect such as a cardiac lesion, he would be graded with an asterisk: OMENS*. This approach adds little complexity to the acronym, but immediately indicates when a patient’s features lie towards the broader oculoauriculovertebral end of the phenotypic spectrum. Does the 0MEN:S system provide any useful information not summa:-ised by other classifications such as the SAT one? Firstly, in common with many other HFM analyses (Longacre et al., 1963; Grabb, 1965; Converse et al.. 1974; Edgerton & Marsh, 1977; Tenconi & Hall, 1983; Murray et al., 1984; Lauritzen et al., 1985; David et al., 1987; Rollnick et al., 1987; Kaban et al., 1988) the mandibular grading is based on Pruzansky’s (1969) original descriptions. The SAT and OMENS systems are also similarly based on
of two
classification
systems
for hcmifacial
microsomia
81
Meurman’s (1957) analysis of ear defects, giving the same grades (Figs 1 & 2). Neither classification, however, has adopted Pruzansky’s modification by including tags as ear anomalies. This is unfortunate since auricular tags may be one of the fundamental markers of HFM. Therefore, the total ear defects in this .study should probably be recorded as 89% (rather than 85%). It is proposed that in future tags be included in the category for minor ear malformation (A,/E,). Vento et al. (1991) chose to distinguish orbital anomalies completely from mandibular defects, with 15% of their cases exhibiting dystopia. In this study, dystopia was present in 43% of affected sides, but the SAT classification of the same data underestimates this by limiting the recording of orbital involvement to the S4 and S, categories (7% of sides). Although there was some disparity between clinical and radiographic dystopia, and orbital anomalies were corrected directly in only a few severe cases, it may still be useful to register dystopia as a measure of skeletal asymmetry. Hence, dystopia may be a secondary defect rather than a primary one. This is in accordance with a recent pathogenic model centred on auriculofacial cartilage deformity (Cousley & Wilson, 1992) and the clinical evidence in both this study and the OMENS one. The SAT soft tissue category has also been split up and modified in the OMENS system. This appears to be helpful since seventh cranial nerve involvement was recorded in 21% of the affected sides. The addition of a So tissue type also refines the classification. Similarly, the addition of a M, grade and the splitting of the M, category into A and R types further clarifies the degree of mandibular deformity. For instance, although mandibular malformation is considered to be the cornerstone of HFM there may bc occasions when it is minimal on the affected side, or more commonly, absent on one side of a bilateral case. These category alterations enable better distinction between the different skeletal and soft tissue deficiency causes of facial scoliosis. which is reflected in subsequent treatment. A classification based on skeletal dysmorphology and its surgical management has been outlined previously (Lauritzcn et al., 1985). Although prognostic and postoperative predictions may be made using this system alone. the broad analytical nature of the OMENS system may improve predictions since it appears to be more sensitive to the wide phenotypic heterogeneity of HFM. Acknowledgements The author thanks Professor Andrew Richardson (Belfast) organisational help, and Mr David J. David, Dr Richard and the rest of the staff and visiting surgeons in Adelaide warmth and assistance during his visit there. He is grateful MIA;BDA Foundation for Elcctivc Awards, the Queen’s sity of Belfast and the Wisdom Dental Student Award for assistance.
for his Harries for their to the Univerfinancial
References Ainamo, J., Barmcs, D., Bcagrie, G., Cutress, T.. Martin, J. & Sardo-Intirri, J. (1982). Development of the World Health
82
British
Journal
Organisation Treatment
of Oral
and Maxillofacial
Surgery
(WHO) Community Periodontal Index of Needs (CPITN). Inrernaiianul Dental Journal.
32.
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The Author H. R. J. Cousley BSc, BDS School of Clinical Dentistry The Queen’s I!niversity of Belfast Belfast BTl2 6BP Northern Ireland Correspondence and requests for offprints to Mr R.R.J. Cousley, IIousc Surgeon, Department of Oral and Maxillofacial Surgery. St. Thomas’ IIospital, London SEI 7EII Paper received 29 June 1992 Accepted 28 August 1992