J Oral Maxillofac 4S:1254-1257.
Surg
1990
The Problem of the Bifid Mandibular Condyle ANDRAS SZENTPE!TERY, DDS, PHD,* GABOR KOCSIS, DDS,t AND ANTbNlA MARCSIK, DBS, PHD* In a survey of 1,882 prehistoric and historic skulls with 2,077 condyles, 7 double (bifid) mandibular condyles were found. One mandible with bilaterally bifid condyles is presented in detail. Possible causes and consequences of the anomaly are discussed. It is assumed that bifid mandibular condyles with anteroposteriorly situated heads are caused by early childhood fractures, whereas those with mediolaterally situated heads are caused by the persistence of connective tissue septa.
To the present, 16 cases of double-headed (bifid) mandibular condyles have been reported in living persons and 25 in skeletal specimens (Table 1). The first and, to the present, most comprehensive description of such cases was made by Hrdlicka’ on 20 human and one gorilla mandible with bifid condyles from the collection of the Smithsonian Institution. Of the cases detected in living persons, some were found during a radiologic survey carried out because of temporomandibular joint (TMJ) complaints,* swelling,3 ankylosis,4 or traumatic fracture5; others were discovered during some other kind of dental survey.6-‘0 Of a total of 41 cases reported in the literature, 4 were bilateral,1~6 and 37 unilateral.1-5,7-14 The splitting of the condyles ranged from a shallow groove6 to two distinct condyles with separate necks.* The orientation of the two heads may be mediolatera12’6*10’11or anteroposterior.3-5*10 Blackwood” and Mofett” have postulated that the retention of connective tissue septa normally
present at an early prenatal age is the cause of the problem. Stadnicki4 thought that the fibrous and subsequent bony ankylosis in his case with a left bifid condyle had been caused by forceps delivery. Thomason and Yusufs observed two cases of traumatic condyle fracture (bicycle accident) that later resulted in both patients developing bifid condyles. These are perhaps the only two cases where the cause is so clearly proved. Gundlach et allo believed that the condition might be caused by maldirected muscle pull. A survey of the literature leads to the conclusion that bifid condyle is a relatively rare phenomenon. However, because of the lack of epidemiologic data, there is no information about the real incidence of this malformation. Therefore, it may be possible that the condition is more frequent than supposed. To assess the prevalence of this phenomenon, we carried out an investigation on skulls from the collection of the Department of Anthropology, Attila J6zsef University, Szeged, Hungary. This article reports the results of that study.
* Head, Preclinic Dentistry, Department of Dentistry and Oral Surgery, Albert Szent-Gyijrgyi Medical University, Szeged, Hungary. t Head, Orthodontics, Department of Dentistry and Oral Surgery, Albert Szent-Gyijrgyi Medical University, Szeged, Hungary. $ Department of Anthropology, Attila J6zsef University, Szeged, Hungary. Address correspondence and reprint requests to Dr Szentp6tery: Prothetische Abteilung, Klinik und Poliklinik fiir Zahn-, Mund-, und Kieferkrankheiten der Universitiit Marburg, Georg-Voigt-Strape 3, D-3550 Marburg 1, Germany.
Materials and Methods
0 1990 geons
American
Association
of Oral
and Maxillofacial
A total of 1,882 skulls with mandibles were studied. The distribution of the mandibles according to the presence or absence of the condyles is shown in Table 2. The skulls were derived essentially from the entire territory of present-day Hungary and date from the Neolithic period to the 18th century. The dating of the skull sample is given in Table 3. All the condyles were assessed macroscopically for signs of doubling. A distinction was made between true doubling (bifid condyle) and cases with only early
Sur-
0278-2391/90/4812-0003$3.00/O
1254
SZENTPGTERY
1255
ET AL
Table 1. Bifid Condyies Reported the Literature
Table 3.
in
Historical Age
No. of Bitid Condyles in Living Persons Skeletons
Author(s)
-
Hrdlicka (1941)’ Sicher (1948)’ Moffett (1966)” Hovinga (1968)” Honde & Bloem (1969)” Stadnicki (1971)“ Lysell & Oberg (1975)’ Farmand (1981)’ Hiils et al (1984)” Forman & Smith (1984)” Balciunas (I 985j9 Thomason & Yusuf (1986)’ Gundlach et al (1987)‘” Sahm & Witt (1989)14 Totals
21
-
1 -
1 -
1 -
1 1
1
1
-
1 1 2 1 2 4 1
-
16
Dating of the Sample N
Neolithic period Copper Age Bronze Age Iron Age 1st to 3rd century (Sarmatians) 7th to 8th century (Avar period) 9th to 10th century (Hungarian Conquest) 11th to 13th century (Arpadian age) 14th to 18th century (Middle Ages) Total
Bitid Condyles
89 263 227 199
-
loo
-
263
2 (in one mandible)
224
-
I
200 244 I.882
4 7
1 f
25 = 41
of different depth and width. No mediolaterally divided condyles were found in this skull collection. Discussion
signs of doubling in the form of some kind of a groove. Results
Among the 1,882 skulls (2077 condyles), 7 cases with signs of a bifid condyle were found. No completely bifd condyles were seen. Of these 7 cases, 2 were left and 5 were right partially bifid condyles; 2 were found in males, 5 in females. In all 7 cases, the grooving was anteroposteriorly directed, dividing the condyles in a medial and a lateral half. One mandible with bilateral signs of grooving is shown in Figures 1 and 2. On the right side, a groove 3 mm deep and wide divides the condyle in a smaller medial and a larger lateral part. On the left side, there are two distinct parts of the articular surface without, however, a distinct groove as on the contralateral side. It appears as if a former split has been partially filled with bone, growing from both sides towards the middle. This repair has been incomplete, however, leaving the remnants of the former groove. The other five partially bifid condyles were split similarily in an anteroposterior direction by grooves
According to our findings, the bifid condyle is a rare phenomenon. Partial division was found on 0.34% of the 2,077 condyles investigated, or on 0.48% of the 1,261 skulls with at least one condyle. However, because of the potential 3,764 condyles of the 1,882 skulls only 2,077 were present, a precise determination of the frequency of the phenomenon is impossible. Two main causes of bifid condyle have been suggested: a developmental cause postulated by Blackwood” and by Moffett” (retention of connective tissue septa), and the traumatic cause suggested by Thomason and Yusur (condylar fracture and subsequent incomplete remodeling). According to Blackwood’s theory, well-vascularized fibrous septa appear in the condylar cartilage at approximately 20 weeks of intrauterine life, extending into the medullary cavity of the developing ascending ramus. Toward the end of the 2nd year of life, these structures become fewer in number and disappear
Table 2. Presence and Absence of Condyies in the investigated Skull Sample N (% Total) Mandibles investigated Mandibles without condyles Mandibles with at least one condyle Mandibles with both condyles Number of condyles
1,882 (100) 621 (33) 1,261 (67) 816 (43) 2,077 (55)
FIGURE 1. Posterior view of right condyle. Note the long and curved groove dividing the condyle in two.
1256
FIGURE 2. Posterior view of left condyle. There is only a shallow remnant of a former groove, filled from both sides by the proliferating medial and lateral parts.
by the 19th month. The presence of one of these septa, or the possible rupture of some of its blood vessels, might impair ossification of the condyle and cause bifid development.” Our bilateral case with an open groove on the right side and a partially filled groove on the left, both running in an anteroposterior direction, might be a good example of Blackwood’s theory. Thomason and Yusufs described two cases of traumatic condyle fracture (bicycle accident) with subsequent unilateral formation of bitid condyles. One of the two heads of these bitid condyles had a normal distal position in the glenoid fossa, whereas the other one was more anteriorly situated, in the position where first dislocated.5 Hotz16 observed radiologically the different stages of condylar remodeling (reformation) after fractures in early childhood. He reports the formation of a new condyle in normal position and the resorption of the fractured one. He supports the idea that the fractured condyle will never form a callus with the rest of the mandible, but undergoes total resorption, and an entirely new condyle is formed in normal position in the glenoid fossa. We have to support his concept, as the development of a new functional condyle has been shown’ and because no functional force would be able to reposition the fractured condyle. Walker” sectioned and dislocated the condyle in Mucaca mulatta monkeys and was able to show development of a remarkedly morphologically identifiable condyle in the upright position. These studies demonstrate good growth potential of the mandibular condyle following fractures in early childhood. However, there is no information concerning the age up to which the formation of a new condyle can occur. The reason why the fractured condyle remains unresorbed in some cases is unknown. Sahm and Witt14 could observe by computed tomography a high degree of remodeling, with a slight notching in
THE PROBLEM OF THE BIFID MANDIBULAR
CONDYLE
the lateral aspect in cases with high condylar fractures, and an unfavorable remodeling in low fractures with luxation of the mandibular head. One of their cases with a low condylar fracture appeared later as a bifid condyle. Therefore, it also may be the site of the fracture and, most probably, its relation to the insertion of the lateral pterygoid muscle that determines the future development of a normal or a bitid condyle. All these findings support the assumption that in the bifid cases where an anterior (anteromedial) and a posterior (posterolateral) condyle is present, the condition has a traumatic origin, namely, early childhood fracture with subsequent incomplete remodeling. It is also very probable that the two forms of bifid condyle, one anteroposterior and one mediolateral, arise on entirely different principles. Whereas anteroposteriorly placed bifid condyles are, most probably, the consequence of early childhood fractures, mediolaterally split ones are more likely the consequence of persisting developmental septa. Whether the changes in the form seen in this investigation have any consequences to the individual is unknown. In the cases with known previous fractures, only a few complaints were detected at the time of observation. A slight restriction of mandibular mobility and facial asymmetry were reported by Thomason and Yusuf.’ In two of the five fracture cases observed by Sahm and Witt,14 soft-tissue ankylosis occurred, with severe limitation of mandibular mobility. In a third case, however, that later developed into a bifid condyle, only a limited restriction of mandibular mobility occurred. The outcome of the condition-normal morphology and function after total remodeling, bifid condyle without functional disturbances, or severe limitation through ankylosis-is probably dependent on the type of the injury (direct or indirect, “high” or “low” fracture), the extent of the damage to the joint structures (disc, capsule, articular surfaces), the presence or absence of inflammation, hemarthrosis, and the age of the patient at the time of the injury. References 1. Hrdlicka A: Lower jaw: Double condyles. Am J Phys AnthropoI2875, 1941 2. Lysell G, Gberg T: Unilateral doubling of mandibular condyle. DentomaxiIlofac Radio1 4:95, 1975 3. Farmand M: Mandibular condylar head duplication. J Maxillofac Surg 959, 1981 4. Stadnicki G: Congenital double condyle of the mandible causing temporomandibuhu ankylosis: Report of case. J Oral Surg 29:208, 1971 5. Thomason JM, Yusuf H: Traumatically induced bifid mandibular condyle: Report of two cases. Br Dent J 161:291, 1986
SZENTPETERY
ET AL
6. Huls A, Walter E, Siiss CH: Anwendungsbereiche der computertomographischen Gelenkdiagnostik. Dtsch Zahnarztl Z 39:933, 1984 7. Sicher MBA: The temporomandibular joint. A consideration of its probable functional and dysfunctional sequelae and report: Condyle-double head-In a living person. Dental Items Interest 70: 1100, 1948 a. Forman GH, Smith NJD: Bifid mandibular condyle. Oral Surg 57:371, 1984 9. Balciunas BA: BiIid mandibular condyle. J Oral Maxillofac Surg 441324, 1986 10. Gundlach KKH, Fuhrman A, Beckmann-Van der Ven G: The double-headed mandibular condyle. Oral Surg Oral Med Oral Path01 ti249, 1987 11. Moffett B: The morphogenesis of the mandibular joint. Am J Orthod 52401, 1966
1257
12. Hovinga J: Verdubbeling van het kaakkopje na een trauma. Ned T Tankleek 11:773, 1%8 13. Ho&e GLJM, Bloem NJBM: Bicondylair caput mandibulae; Een anatomische variatie in het kaakgewricht. Ned T Tandleek 76:894, 1%9 14. Sahm G, Witt E: Long-term results after childhood condylar fractures. A computer-tomographic study. Eur J Orthod 11: 154, 1989 15. Blackwood HJJ: The double-headed mandibular condyle. Am J Phys Anthropol lS:l, 1957 16. Hotz RP: Functional jaw orthopedics in the treatment of condylar fractures. Am J Orthod 73:365, 1978 17. Walker RV: Traumatic mandibular condyle fracture dislocations. Effect on growth in the Macacn rhesus monkey. Am J Surg 100:850, 1960
Surg
1990
The Problem of the Bifid Mandibular Condyle ANDRAS SZENTPE!TERY, DDS, PHD,* GABOR KOCSIS, DDS,t AND ANTbNlA MARCSIK, DBS, PHD* In a survey of 1,882 prehistoric and historic skulls with 2,077 condyles, 7 double (bifid) mandibular condyles were found. One mandible with bilaterally bifid condyles is presented in detail. Possible causes and consequences of the anomaly are discussed. It is assumed that bifid mandibular condyles with anteroposteriorly situated heads are caused by early childhood fractures, whereas those with mediolaterally situated heads are caused by the persistence of connective tissue septa.
To the present, 16 cases of double-headed (bifid) mandibular condyles have been reported in living persons and 25 in skeletal specimens (Table 1). The first and, to the present, most comprehensive description of such cases was made by Hrdlicka’ on 20 human and one gorilla mandible with bifid condyles from the collection of the Smithsonian Institution. Of the cases detected in living persons, some were found during a radiologic survey carried out because of temporomandibular joint (TMJ) complaints,* swelling,3 ankylosis,4 or traumatic fracture5; others were discovered during some other kind of dental survey.6-‘0 Of a total of 41 cases reported in the literature, 4 were bilateral,1~6 and 37 unilateral.1-5,7-14 The splitting of the condyles ranged from a shallow groove6 to two distinct condyles with separate necks.* The orientation of the two heads may be mediolatera12’6*10’11or anteroposterior.3-5*10 Blackwood” and Mofett” have postulated that the retention of connective tissue septa normally
present at an early prenatal age is the cause of the problem. Stadnicki4 thought that the fibrous and subsequent bony ankylosis in his case with a left bifid condyle had been caused by forceps delivery. Thomason and Yusufs observed two cases of traumatic condyle fracture (bicycle accident) that later resulted in both patients developing bifid condyles. These are perhaps the only two cases where the cause is so clearly proved. Gundlach et allo believed that the condition might be caused by maldirected muscle pull. A survey of the literature leads to the conclusion that bifid condyle is a relatively rare phenomenon. However, because of the lack of epidemiologic data, there is no information about the real incidence of this malformation. Therefore, it may be possible that the condition is more frequent than supposed. To assess the prevalence of this phenomenon, we carried out an investigation on skulls from the collection of the Department of Anthropology, Attila J6zsef University, Szeged, Hungary. This article reports the results of that study.
* Head, Preclinic Dentistry, Department of Dentistry and Oral Surgery, Albert Szent-Gyijrgyi Medical University, Szeged, Hungary. t Head, Orthodontics, Department of Dentistry and Oral Surgery, Albert Szent-Gyijrgyi Medical University, Szeged, Hungary. $ Department of Anthropology, Attila J6zsef University, Szeged, Hungary. Address correspondence and reprint requests to Dr Szentp6tery: Prothetische Abteilung, Klinik und Poliklinik fiir Zahn-, Mund-, und Kieferkrankheiten der Universitiit Marburg, Georg-Voigt-Strape 3, D-3550 Marburg 1, Germany.
Materials and Methods
0 1990 geons
American
Association
of Oral
and Maxillofacial
A total of 1,882 skulls with mandibles were studied. The distribution of the mandibles according to the presence or absence of the condyles is shown in Table 2. The skulls were derived essentially from the entire territory of present-day Hungary and date from the Neolithic period to the 18th century. The dating of the skull sample is given in Table 3. All the condyles were assessed macroscopically for signs of doubling. A distinction was made between true doubling (bifid condyle) and cases with only early
Sur-
0278-2391/90/4812-0003$3.00/O
1254
SZENTPGTERY
1255
ET AL
Table 1. Bifid Condyies Reported the Literature
Table 3.
in
Historical Age
No. of Bitid Condyles in Living Persons Skeletons
Author(s)
-
Hrdlicka (1941)’ Sicher (1948)’ Moffett (1966)” Hovinga (1968)” Honde & Bloem (1969)” Stadnicki (1971)“ Lysell & Oberg (1975)’ Farmand (1981)’ Hiils et al (1984)” Forman & Smith (1984)” Balciunas (I 985j9 Thomason & Yusuf (1986)’ Gundlach et al (1987)‘” Sahm & Witt (1989)14 Totals
21
-
1 -
1 -
1 -
1 1
1
1
-
1 1 2 1 2 4 1
-
16
Dating of the Sample N
Neolithic period Copper Age Bronze Age Iron Age 1st to 3rd century (Sarmatians) 7th to 8th century (Avar period) 9th to 10th century (Hungarian Conquest) 11th to 13th century (Arpadian age) 14th to 18th century (Middle Ages) Total
Bitid Condyles
89 263 227 199
-
loo
-
263
2 (in one mandible)
224
-
I
200 244 I.882
4 7
1 f
25 = 41
of different depth and width. No mediolaterally divided condyles were found in this skull collection. Discussion
signs of doubling in the form of some kind of a groove. Results
Among the 1,882 skulls (2077 condyles), 7 cases with signs of a bifid condyle were found. No completely bifd condyles were seen. Of these 7 cases, 2 were left and 5 were right partially bifid condyles; 2 were found in males, 5 in females. In all 7 cases, the grooving was anteroposteriorly directed, dividing the condyles in a medial and a lateral half. One mandible with bilateral signs of grooving is shown in Figures 1 and 2. On the right side, a groove 3 mm deep and wide divides the condyle in a smaller medial and a larger lateral part. On the left side, there are two distinct parts of the articular surface without, however, a distinct groove as on the contralateral side. It appears as if a former split has been partially filled with bone, growing from both sides towards the middle. This repair has been incomplete, however, leaving the remnants of the former groove. The other five partially bifid condyles were split similarily in an anteroposterior direction by grooves
According to our findings, the bifid condyle is a rare phenomenon. Partial division was found on 0.34% of the 2,077 condyles investigated, or on 0.48% of the 1,261 skulls with at least one condyle. However, because of the potential 3,764 condyles of the 1,882 skulls only 2,077 were present, a precise determination of the frequency of the phenomenon is impossible. Two main causes of bifid condyle have been suggested: a developmental cause postulated by Blackwood” and by Moffett” (retention of connective tissue septa), and the traumatic cause suggested by Thomason and Yusur (condylar fracture and subsequent incomplete remodeling). According to Blackwood’s theory, well-vascularized fibrous septa appear in the condylar cartilage at approximately 20 weeks of intrauterine life, extending into the medullary cavity of the developing ascending ramus. Toward the end of the 2nd year of life, these structures become fewer in number and disappear
Table 2. Presence and Absence of Condyies in the investigated Skull Sample N (% Total) Mandibles investigated Mandibles without condyles Mandibles with at least one condyle Mandibles with both condyles Number of condyles
1,882 (100) 621 (33) 1,261 (67) 816 (43) 2,077 (55)
FIGURE 1. Posterior view of right condyle. Note the long and curved groove dividing the condyle in two.
1256
FIGURE 2. Posterior view of left condyle. There is only a shallow remnant of a former groove, filled from both sides by the proliferating medial and lateral parts.
by the 19th month. The presence of one of these septa, or the possible rupture of some of its blood vessels, might impair ossification of the condyle and cause bifid development.” Our bilateral case with an open groove on the right side and a partially filled groove on the left, both running in an anteroposterior direction, might be a good example of Blackwood’s theory. Thomason and Yusufs described two cases of traumatic condyle fracture (bicycle accident) with subsequent unilateral formation of bitid condyles. One of the two heads of these bitid condyles had a normal distal position in the glenoid fossa, whereas the other one was more anteriorly situated, in the position where first dislocated.5 Hotz16 observed radiologically the different stages of condylar remodeling (reformation) after fractures in early childhood. He reports the formation of a new condyle in normal position and the resorption of the fractured one. He supports the idea that the fractured condyle will never form a callus with the rest of the mandible, but undergoes total resorption, and an entirely new condyle is formed in normal position in the glenoid fossa. We have to support his concept, as the development of a new functional condyle has been shown’ and because no functional force would be able to reposition the fractured condyle. Walker” sectioned and dislocated the condyle in Mucaca mulatta monkeys and was able to show development of a remarkedly morphologically identifiable condyle in the upright position. These studies demonstrate good growth potential of the mandibular condyle following fractures in early childhood. However, there is no information concerning the age up to which the formation of a new condyle can occur. The reason why the fractured condyle remains unresorbed in some cases is unknown. Sahm and Witt14 could observe by computed tomography a high degree of remodeling, with a slight notching in
THE PROBLEM OF THE BIFID MANDIBULAR
CONDYLE
the lateral aspect in cases with high condylar fractures, and an unfavorable remodeling in low fractures with luxation of the mandibular head. One of their cases with a low condylar fracture appeared later as a bifid condyle. Therefore, it also may be the site of the fracture and, most probably, its relation to the insertion of the lateral pterygoid muscle that determines the future development of a normal or a bitid condyle. All these findings support the assumption that in the bifid cases where an anterior (anteromedial) and a posterior (posterolateral) condyle is present, the condition has a traumatic origin, namely, early childhood fracture with subsequent incomplete remodeling. It is also very probable that the two forms of bifid condyle, one anteroposterior and one mediolateral, arise on entirely different principles. Whereas anteroposteriorly placed bifid condyles are, most probably, the consequence of early childhood fractures, mediolaterally split ones are more likely the consequence of persisting developmental septa. Whether the changes in the form seen in this investigation have any consequences to the individual is unknown. In the cases with known previous fractures, only a few complaints were detected at the time of observation. A slight restriction of mandibular mobility and facial asymmetry were reported by Thomason and Yusuf.’ In two of the five fracture cases observed by Sahm and Witt,14 soft-tissue ankylosis occurred, with severe limitation of mandibular mobility. In a third case, however, that later developed into a bifid condyle, only a limited restriction of mandibular mobility occurred. The outcome of the condition-normal morphology and function after total remodeling, bifid condyle without functional disturbances, or severe limitation through ankylosis-is probably dependent on the type of the injury (direct or indirect, “high” or “low” fracture), the extent of the damage to the joint structures (disc, capsule, articular surfaces), the presence or absence of inflammation, hemarthrosis, and the age of the patient at the time of the injury. References 1. Hrdlicka A: Lower jaw: Double condyles. Am J Phys AnthropoI2875, 1941 2. Lysell G, Gberg T: Unilateral doubling of mandibular condyle. DentomaxiIlofac Radio1 4:95, 1975 3. Farmand M: Mandibular condylar head duplication. J Maxillofac Surg 959, 1981 4. Stadnicki G: Congenital double condyle of the mandible causing temporomandibuhu ankylosis: Report of case. J Oral Surg 29:208, 1971 5. Thomason JM, Yusuf H: Traumatically induced bifid mandibular condyle: Report of two cases. Br Dent J 161:291, 1986
SZENTPETERY
ET AL
6. Huls A, Walter E, Siiss CH: Anwendungsbereiche der computertomographischen Gelenkdiagnostik. Dtsch Zahnarztl Z 39:933, 1984 7. Sicher MBA: The temporomandibular joint. A consideration of its probable functional and dysfunctional sequelae and report: Condyle-double head-In a living person. Dental Items Interest 70: 1100, 1948 a. Forman GH, Smith NJD: Bifid mandibular condyle. Oral Surg 57:371, 1984 9. Balciunas BA: BiIid mandibular condyle. J Oral Maxillofac Surg 441324, 1986 10. Gundlach KKH, Fuhrman A, Beckmann-Van der Ven G: The double-headed mandibular condyle. Oral Surg Oral Med Oral Path01 ti249, 1987 11. Moffett B: The morphogenesis of the mandibular joint. Am J Orthod 52401, 1966
1257
12. Hovinga J: Verdubbeling van het kaakkopje na een trauma. Ned T Tankleek 11:773, 1%8 13. Ho&e GLJM, Bloem NJBM: Bicondylair caput mandibulae; Een anatomische variatie in het kaakgewricht. Ned T Tandleek 76:894, 1%9 14. Sahm G, Witt E: Long-term results after childhood condylar fractures. A computer-tomographic study. Eur J Orthod 11: 154, 1989 15. Blackwood HJJ: The double-headed mandibular condyle. Am J Phys Anthropol lS:l, 1957 16. Hotz RP: Functional jaw orthopedics in the treatment of condylar fractures. Am J Orthod 73:365, 1978 17. Walker RV: Traumatic mandibular condyle fracture dislocations. Effect on growth in the Macacn rhesus monkey. Am J Surg 100:850, 1960
