.I Oral Maxillofac 48:1258-1262,
Surg
1990
Conventional Radiographic and Computed Tomographic Findings in Cases of Fracture of the Mandibular Condylar Process AUNE
KY&T1
DDS, PHD,* JUHANI PYHTINEN, MD, PHD,t DDS, PHD,+ AND MIKKO ALTONEN, DDS, MD, PHD§
M. RAUSTIA,
S. OIKARINEN
A total of 40 patients with 46 fractures of the mandibular condylar process were examined an average of 47 months after the injury. The conventional radiologic examination consisted of panoramic radiography and lateral transcranial view of the fracture in the mouth-open and mouth-closed positions. Sixteen patients with 21 fractures of the condylar process were examined additionally by computed tomography (CT) because of temporomandibular joint problems in the sagittal and coronal projection. Computed tomography revealed bony changes in the fractured mandibular condyle and its position in the mandibular fossa more exactly than conventional radiographic examinations. Furthermore, the results showed that disturbances in the position and function of the articular disc may be more common than was earlier anticipated, suggesting the more frequent use of CT examinations to evaluate temporomandibular joint changes after condylar process fractures.
cess in the anterioposterior direction, but not in the lateromedial direction. Additional exposures, such as a lateral transcranial view or anteroposterior exposures, are imprecise in the condylar region due to the complicated anatomical bone structures in the area.’ Computed tomography (CT) has been used primarily for the diagnosis of internal derangements of the temporomandibular joint (TMJ), but is also a highly suitable method for examining fractures of the mandibular condylar process because it has the advantage of revealing bony and soft-tissue changes at the same time and allowing the use of various projections. 3-5The aim of the present study was to compare findings related to fractures of the mandibular condylar process as seen in conventional radiographs and CT.
The diagnosis of fracture of the mandibular condylar process is based on clinical and radiologic findings. Clinical signs such as jaw deviation and limitation during mouth opening, changes in occlusion, or extraoral swelling of the preauricular region can be indicative of unilateral or bilateral fractures of the condylar process.’ The panoramic radiograph is the conventional form of radiography used, giving an overall view of the fractured mandible and showing the displacement of the fractured condylar proReceived from the University of Oulu, Finland. * Assistant Teacher, Department of Prosthodontics and Stomatognathic Physiology. t Associate Professor, Department of Diagnostic Radiology. $ Assistant Teacher, Department of Oral and Maxillofacial Surgery. $ Professor and Head, Department of Oral and Maxillofacial Surgery. Address correspondence and reprint requests to Dr Raustia: Department of Prosthodontics and Stomatognathic Physiology, Institute of Dentistry, University of Oulu, Aapistie 3, SF-90220 Oulu, Finland. 0 1990 American geons
Association
of Oral and Maxillofacial
Materials and Methods A total of 40 patients with 46 fractures of the mandibular condylar process were examined an average of 47 months after the injury (range, 9 to 106 months). The mean age of the patients, 29 men and
Sur-
0278-2391/90/4812-0004$3.00/0
1258
1259
RAUSTIA ET AL
11 women, was 29 years (range, 16 to 45 years). All the fractures were treated conservatively by maxillomandibular fixation (MMF), the duration of which varied between 16 to 45 days (mean, 30 days). All patients were examined clinically and radiologically by the authors. The radiologic examination consisted of panoramic radiography and a lateral transcranial view of the fractured condylar process in the mouth-open and mouth-closed positions. In addition, 16 patients with 21 fractured condylar processes were examined by CT (Toshiba TCT-80 A) in sagittal and coronal projection an average of 32 months after the injury (range, 6 to 85 months) because of TMJ problems. Direct sagittal CT of the fractured condylar process was performed with the patient lying supine on a stretcher placed lateral to the gantry. The fractured TMJ was then scanned from the medial to the lateral direction using continuous 2-mm slices. The scans were usually obtained with the mouth in closed, semiclosed, and maximally open positions. The slice thickness in coronal projection was 5 mm, and sufficient slices were taken (usually 2 to 4) for both condylar processes to be seen. Results
Seventy-two percent of the fractured condylar processes examined in conventional radiographs were estimated to be in normal position in relation to the mandibular fossa, whereas 17% were in an anterior position and 11% in an anteroinferior position (Table 1). Typical bony changes diagnosed on the fractured side at the follow-up examination were flattening, erosion, osteophytes, and sclerosis of the condyle (Table 1). Most of the condyles were diagnosed as having movement within the normal limits, but 20% had restricted excursion and 6% had abnormally wide excursion. Table 1. Summary of Conventional Radiographic Findings in 46 TMJs (40 Patients) Mandibular condyle Position in mandibular fossa (mouth closed) Normal position Situated anteriorly Situated anteroinferiorly Bone changes Flattening Erosion Osteophytes Sclerosis Function Normal excursion Restricted excursion Greater than normal excursion
33 8 5 9 3 3 7 34 9 3
Comparison of the direct sagittal slices of 21 TMJs with the results of the lateral transcranial radiographs showed that the position of the condyle and the bony changes and restrictions in movement were illustrated more exactly by CT than by lateral transcranial radiography (Table 2, Figs 1 and 2). Small bony changes in the condyle, such as erosion, cortical bone loss, and osteophytes, were diagnosed only by CT in these 21 TMJs. A summary of the direct sagittal CT findings concerning the position and function of the TMJ disc is given in Table 3. The disc was seen in 19 of the 21 TMJs scanned and was in the normal position between the articular surfaces in the mouth-closed position in 12 cases and was functioning normally in 8 cases. An abnormal position of the disc, situated either anteriorly, anteromedially, or posteriorly in the mouth-closed position, was visible in 7 of the 11 cases with abnormal function of the disc (Figs 2 to 4). Clear anterior displacement with reduction was observed in 4 and anterior displacement of the disc without reduction in 3 TMJs. In two cases, the function of the disc was not visible because of severely restricted movement of the condyle. In addition to abnormal position and function of the disc, soft-tissue changes resembling adhesions between the fractured condyle and the articular tubercle were documented in eight cases (Figs 2 to 4). Computed tomography scans in coronal projection showed that the condyle was turned medially in Table 2. Comparison of Direct Sagittal CT Bone Findings With Lateral Tnnacranial Radiographic Findings in 21 TMJs (16 Patients) Mandibular Condyle Position in mandibular fossa (mouth closed) Normal position Situated anteriorly Situated anterorinferiorly Situated posteriorly Bone changes Flattening Erosion Cortical bone loss Osteophytes Sclerosis Deformation of the condylei condylar neck Function Normal excursion Restricted excursion Greater than normal excursion Not seen
CT Findings
I
X-Ray Findings
II
9 4
5 5
7 10 4 -
12 5 3
I
1260
RADIOGRAPHIC
AND CT IN CONDYLAR PROCESS FRACTURES
FIGURE 1. A, Panoramic radiograph of a patient with a fracture of the right mandibular condylar process. The condyle is situated anteriorly in the mandibular fossa and flattening is seen. B, Coronal projection of the right and left condylar process of the same patient. The fractured condylar process is situated medially in relation to the mandibular fossa.
half of the 21 TMJs (Table 4). Other marked deformation of the condyle, the mandibular neck, and flattening, sclerosis of the condyle (Figs 1B and
findings were shortening of erosion, and 4A).
Discussion Computed tomography is a suitable method for diagnosing high condylar process and other facial fractures not seen in conventional radiographs.6‘8 It reveals bone abnormalities in the TMJ, eg, cortical bone loss or sclerosis, and changes in joint morphology and condyle position in the mandibular fossa three-dimensionally without any other structures projected over them.’ Comparison of the results of conventional radiography and CT regarding 21 TMJs (Table 2) showed that an anterior position of the condyle and restricted movements were more
often diagnosed from the CT scan than from the conventional radiograph, probably because conventional radiography of the condylar area is unclear to some extent due to the complicated bony anatomy (Fig 2). Computed tomography revealed smaller bony changes better than conventional radiographic examinations, because there must be at least 40% loss of bony substance before any noticeable changes will be seen in plain radiographs.” A coronal CT projection is very suitable for evaluating the position of the condyle in the mandibular fossa in a mediolateral direction (Figs 1B and 4A). In addition, coronal slices of the TMJ visualize well the superior and medial parts of the condyle and the mandibular fossa. ‘I The bony changes seen in this projection are more accurately diagnosed than with a conventional posteroanterior view due to the excellent resolution of CT. Apart from magnetic res-
1261
RAUSTIA ET AL
FIGURE 2. A. Lateral transcranial radiograph of the fractured malndibular condylar process of the same patient as in Figure 1. B, Direct sagittal CT of the same TMJ in mouth-closed position (bone window view). The condyle is situated anteriorly and flattening is obvious. C, In mouth-closed position (soft-tissue window), the disc is seen in an abnormal position, posteriorly in relation to the condyle (white arrow). D, In maximal mouth-open position (soft-tissue window), a soft-tissue mass resembling an adhesion is seen between the articular surfaces (arrows).
Table 3. timmary of Direct 8rglttal CT Findings Regarding the Disc (21 TMJs) Position of the disc Normal position Situated anteriorly Situated posteriorly Not seen Function of the disc Normal function Abnormal function Anterior displacement Anterior displacement Not seen Adhesions
12 6
1 2
with reduction without reduction
8 11 4 3 2 8
onance imaging (MRI), CT is the only noninvasive modality that can show changes of the position and function of the disc without contrast medium.3*12*13 Few reports are available on the TMJ disc in patients with mandibular condylar process fractures,5 but the present results suggest that disturbances in the position and function of the articular disc may be more common than was earlier anticipated, and speak in favor of using CT scanning more often to evaluate changes in TMJs after condylar process fractures. Furthermore, soft-tissue changes resembling adhesions are also detectable by CT (Table 3). The patient whose fractured condyle is seen in Fig-
1262
RADIOGRAPHIC
AND CT IN CONDYLAR PROCESS FRACTURES
FIGURE 3. Direct sagittal CT of the fractured mandibular condylar process showing anterior disc displacement with reduction. A, In mouth-closed position (soft-tissue window), the disc is situated anteriorly in relation to the condyle (white arrow). B, In maximal mouth-open position, the disc is in a reduced normal position posterior to the condyle (arrow). Normal condylar excursion is seen. Insertion of the lateral pterygoid muscle (arrowheads).
ure 4 had severely and continual pain The TMJ was later adherent disc and
limited mouth-opening capacity in the region of the right TMJ. exposed surgically and a totally partially fibrous ankylosis were
found. In addition to these features, changes in the size and density of the masticatory muscles . ,have been observed in CT scans of such patients.” It can be concluded that CT is able to reveal bony
FIGURE 4. A, Coronal CT of the right and left TMJs of a patient with severely limited mouth opening. The fractured condyle (on the right) is turned medially and a lateral osteophyte is seen (arrow). B, Direct sagittal CT of the same TMJ. The condyle is situated anteriorly against the articular tubercle in the mouth-closed position (bone window). C, The disc is seen posterior to the condyle (white arrow) (soft-tissue window). D, In maximal mouth-open position (bone window), the condyle has moved just a little.
1263
AMIL J. GERLOCK JR
Table 4.
Main CoronalCT Findings(21 TMJs) N
Condyle turned medially Deformation of the condyle Shortening of the condylar neck Erosion Flattening Sclerosis
12 4 4 5 3
1
condylar changes following fractures, as well as changes in relation of the condyle to the mandibular fossa, more exactly than conventional radiographic examinations. The direction of displacement of the fractured condyle, both anteroposteriorly and mediolaterally, is also seen better by CT than by conventional radiographs. Changes in the position and function of the disc are not seen in conventional radiographs without contrast medium, but are illustrated by CT. Magnetic resonance imaging may complement CT in the future for the diagnosis of disc dysfunction and other structural changes in the TMJ. References 1. Rowe NL, Williams JLC: Maxillofacial Injuries, vol I. New York, NY, Churchill Livingstone, 1985 2. Ekerdal 0: Tomography of the temporomandibular joint: Correlation between tomographic image and histologic
sections in a three-dimensional system. Acta Radio1 329:1, 1973 (suppl) 3. Raustia AM, Pyhtinen J, Virtanen KK: Examination of the temporomandibular joint by direct sagittal computed tomography. Clin Radio1 36:291, 1985 4. Wegener OH, Balan EH, Bier J: Das Computertmogramm zur Beurteilung des Kiefergelenkes. Dtsch Z MundKiefer-Gesichts-Chir 2:30, 1978 5. Christiansen EL, Thompson JR, Hasso AN: CT evaluation of trauma to the temporomandibular joint. J Oral Maxillofac Surg 45:920, 1987 6. Fujii N, Yamasiro M: Computed tomography for the diagnosis of facial fractures. J Oral Surg 39:735, 1981 7. Htils A, von Ehrlich V, Haase S, et al: Computertomographie des frakturierten Unterkiefergelekfortsatzes. Dtsch Zahnartzl Z 38:333, 1983 8. Davis WM Jr: An interesting condylar fracture revealed by use of computed tomography. Oral Surg 67:3 1, 1989 9. Raustia AM, Pyhtinen J: Computed tomography of the masticatory system-A review. Comput Med Imaging Graph 12:97, 1988 10. Stoker DJ: Skeletal disorders of metabolic and endocrine origin, in Sutton D (ed): A Textbook of Radiology and lmaging (ed 3). New York, Churchill Livingstone. 1980. p 166 11. Raustia AM, Pyhtinen J: Morphology of the caput mandibulae and mandibular fossa as seen by computed tomography. J Prosthet Dent 63:77, 1990 12. Raustia AM, Pyhtinen J: Direct sagittal computed tomography as a diagnostic aid in the treatment of an anteriorly displaced temporomandibular joint disc by splint therapy. J Craniomandibular Practice 5:240, 1987 13. Schellehas KP, Wilkes CH, Fritts HM, et al: Temporomandibular joint: MR imaging of internal derangements and postoperative changes. AJNR 8:1093, 1987 14. Oikarinen KS, Raustia AM, Pyhtinen J: CT of main masticatory muscles after mandibular condyle fracture. J Dent Res 68: 1003, 1989 (IADR abstr 1094)
J Oral MaxillofacSurg 46:1X+1264.1990
Discussion Conventional Radiographic and Computed Tomographic Findings in Cases of Fracture of the Mandibular Condylar Process Amil J. Gerlock Jr, MD University of Texas Medical School, Hermann Houston
Hospital,
As stated by these authors, “the aim of the present study was to compare findings related to fractures of the mandibular condylar process as seen in conventional radiographs and computed tomography.” They concluded “that CT is able to reveal bony condylar changes following fractures, as well as changes in relation of the condyles to the mandibular fossa, more exactly than conventional radiographic examination.” This does not represent a new concept or come as any great surprise. Furthermore, these authors performed computed tomography (CT) on 16 patients with 21 fractured condylar processes an average of 32 months after the injury. The indication for CT was temporomandibular joint (TMJ)
problems. From these data, the authors suggest that disturbances in the position and function of the articular disc from trauma may be more common than was earlier anticipated. Again, this comes as no surprise. Previous reports have identified trauma as a major antecedent of TMJ derangement. ‘-I3 This study would have been more informative if it focused on which imaging modalities to use and when to use them. The increased interest in TMJ dysfunction in the past 3 to 5 years has produced a flurry of reports in the literature concerning a wide variety of imaging modalities. These include plain radiography, tomography, arthrography, CT, magnetic resonance imaging (MRI) and radionuclide imaging. Because all of these examinations cannot be used, imaging algorithms should be developed that allow early diagnosis of TMJ internal derangements to be made and corrected before they produce progressive joint degeneration and clinical disability. Presently, early imaging with MR (or arthrography if MRI cannot be performed) and TMJ radiographytomography have been advocated to assess the type and extent of injury to the TMJ after injury.i4 Perhaps early
Surg
1990
Conventional Radiographic and Computed Tomographic Findings in Cases of Fracture of the Mandibular Condylar Process AUNE
KY&T1
DDS, PHD,* JUHANI PYHTINEN, MD, PHD,t DDS, PHD,+ AND MIKKO ALTONEN, DDS, MD, PHD§
M. RAUSTIA,
S. OIKARINEN
A total of 40 patients with 46 fractures of the mandibular condylar process were examined an average of 47 months after the injury. The conventional radiologic examination consisted of panoramic radiography and lateral transcranial view of the fracture in the mouth-open and mouth-closed positions. Sixteen patients with 21 fractures of the condylar process were examined additionally by computed tomography (CT) because of temporomandibular joint problems in the sagittal and coronal projection. Computed tomography revealed bony changes in the fractured mandibular condyle and its position in the mandibular fossa more exactly than conventional radiographic examinations. Furthermore, the results showed that disturbances in the position and function of the articular disc may be more common than was earlier anticipated, suggesting the more frequent use of CT examinations to evaluate temporomandibular joint changes after condylar process fractures.
cess in the anterioposterior direction, but not in the lateromedial direction. Additional exposures, such as a lateral transcranial view or anteroposterior exposures, are imprecise in the condylar region due to the complicated anatomical bone structures in the area.’ Computed tomography (CT) has been used primarily for the diagnosis of internal derangements of the temporomandibular joint (TMJ), but is also a highly suitable method for examining fractures of the mandibular condylar process because it has the advantage of revealing bony and soft-tissue changes at the same time and allowing the use of various projections. 3-5The aim of the present study was to compare findings related to fractures of the mandibular condylar process as seen in conventional radiographs and CT.
The diagnosis of fracture of the mandibular condylar process is based on clinical and radiologic findings. Clinical signs such as jaw deviation and limitation during mouth opening, changes in occlusion, or extraoral swelling of the preauricular region can be indicative of unilateral or bilateral fractures of the condylar process.’ The panoramic radiograph is the conventional form of radiography used, giving an overall view of the fractured mandible and showing the displacement of the fractured condylar proReceived from the University of Oulu, Finland. * Assistant Teacher, Department of Prosthodontics and Stomatognathic Physiology. t Associate Professor, Department of Diagnostic Radiology. $ Assistant Teacher, Department of Oral and Maxillofacial Surgery. $ Professor and Head, Department of Oral and Maxillofacial Surgery. Address correspondence and reprint requests to Dr Raustia: Department of Prosthodontics and Stomatognathic Physiology, Institute of Dentistry, University of Oulu, Aapistie 3, SF-90220 Oulu, Finland. 0 1990 American geons
Association
of Oral and Maxillofacial
Materials and Methods A total of 40 patients with 46 fractures of the mandibular condylar process were examined an average of 47 months after the injury (range, 9 to 106 months). The mean age of the patients, 29 men and
Sur-
0278-2391/90/4812-0004$3.00/0
1258
1259
RAUSTIA ET AL
11 women, was 29 years (range, 16 to 45 years). All the fractures were treated conservatively by maxillomandibular fixation (MMF), the duration of which varied between 16 to 45 days (mean, 30 days). All patients were examined clinically and radiologically by the authors. The radiologic examination consisted of panoramic radiography and a lateral transcranial view of the fractured condylar process in the mouth-open and mouth-closed positions. In addition, 16 patients with 21 fractured condylar processes were examined by CT (Toshiba TCT-80 A) in sagittal and coronal projection an average of 32 months after the injury (range, 6 to 85 months) because of TMJ problems. Direct sagittal CT of the fractured condylar process was performed with the patient lying supine on a stretcher placed lateral to the gantry. The fractured TMJ was then scanned from the medial to the lateral direction using continuous 2-mm slices. The scans were usually obtained with the mouth in closed, semiclosed, and maximally open positions. The slice thickness in coronal projection was 5 mm, and sufficient slices were taken (usually 2 to 4) for both condylar processes to be seen. Results
Seventy-two percent of the fractured condylar processes examined in conventional radiographs were estimated to be in normal position in relation to the mandibular fossa, whereas 17% were in an anterior position and 11% in an anteroinferior position (Table 1). Typical bony changes diagnosed on the fractured side at the follow-up examination were flattening, erosion, osteophytes, and sclerosis of the condyle (Table 1). Most of the condyles were diagnosed as having movement within the normal limits, but 20% had restricted excursion and 6% had abnormally wide excursion. Table 1. Summary of Conventional Radiographic Findings in 46 TMJs (40 Patients) Mandibular condyle Position in mandibular fossa (mouth closed) Normal position Situated anteriorly Situated anteroinferiorly Bone changes Flattening Erosion Osteophytes Sclerosis Function Normal excursion Restricted excursion Greater than normal excursion
33 8 5 9 3 3 7 34 9 3
Comparison of the direct sagittal slices of 21 TMJs with the results of the lateral transcranial radiographs showed that the position of the condyle and the bony changes and restrictions in movement were illustrated more exactly by CT than by lateral transcranial radiography (Table 2, Figs 1 and 2). Small bony changes in the condyle, such as erosion, cortical bone loss, and osteophytes, were diagnosed only by CT in these 21 TMJs. A summary of the direct sagittal CT findings concerning the position and function of the TMJ disc is given in Table 3. The disc was seen in 19 of the 21 TMJs scanned and was in the normal position between the articular surfaces in the mouth-closed position in 12 cases and was functioning normally in 8 cases. An abnormal position of the disc, situated either anteriorly, anteromedially, or posteriorly in the mouth-closed position, was visible in 7 of the 11 cases with abnormal function of the disc (Figs 2 to 4). Clear anterior displacement with reduction was observed in 4 and anterior displacement of the disc without reduction in 3 TMJs. In two cases, the function of the disc was not visible because of severely restricted movement of the condyle. In addition to abnormal position and function of the disc, soft-tissue changes resembling adhesions between the fractured condyle and the articular tubercle were documented in eight cases (Figs 2 to 4). Computed tomography scans in coronal projection showed that the condyle was turned medially in Table 2. Comparison of Direct Sagittal CT Bone Findings With Lateral Tnnacranial Radiographic Findings in 21 TMJs (16 Patients) Mandibular Condyle Position in mandibular fossa (mouth closed) Normal position Situated anteriorly Situated anterorinferiorly Situated posteriorly Bone changes Flattening Erosion Cortical bone loss Osteophytes Sclerosis Deformation of the condylei condylar neck Function Normal excursion Restricted excursion Greater than normal excursion Not seen
CT Findings
I
X-Ray Findings
II
9 4
5 5
7 10 4 -
12 5 3
I
1260
RADIOGRAPHIC
AND CT IN CONDYLAR PROCESS FRACTURES
FIGURE 1. A, Panoramic radiograph of a patient with a fracture of the right mandibular condylar process. The condyle is situated anteriorly in the mandibular fossa and flattening is seen. B, Coronal projection of the right and left condylar process of the same patient. The fractured condylar process is situated medially in relation to the mandibular fossa.
half of the 21 TMJs (Table 4). Other marked deformation of the condyle, the mandibular neck, and flattening, sclerosis of the condyle (Figs 1B and
findings were shortening of erosion, and 4A).
Discussion Computed tomography is a suitable method for diagnosing high condylar process and other facial fractures not seen in conventional radiographs.6‘8 It reveals bone abnormalities in the TMJ, eg, cortical bone loss or sclerosis, and changes in joint morphology and condyle position in the mandibular fossa three-dimensionally without any other structures projected over them.’ Comparison of the results of conventional radiography and CT regarding 21 TMJs (Table 2) showed that an anterior position of the condyle and restricted movements were more
often diagnosed from the CT scan than from the conventional radiograph, probably because conventional radiography of the condylar area is unclear to some extent due to the complicated bony anatomy (Fig 2). Computed tomography revealed smaller bony changes better than conventional radiographic examinations, because there must be at least 40% loss of bony substance before any noticeable changes will be seen in plain radiographs.” A coronal CT projection is very suitable for evaluating the position of the condyle in the mandibular fossa in a mediolateral direction (Figs 1B and 4A). In addition, coronal slices of the TMJ visualize well the superior and medial parts of the condyle and the mandibular fossa. ‘I The bony changes seen in this projection are more accurately diagnosed than with a conventional posteroanterior view due to the excellent resolution of CT. Apart from magnetic res-
1261
RAUSTIA ET AL
FIGURE 2. A. Lateral transcranial radiograph of the fractured malndibular condylar process of the same patient as in Figure 1. B, Direct sagittal CT of the same TMJ in mouth-closed position (bone window view). The condyle is situated anteriorly and flattening is obvious. C, In mouth-closed position (soft-tissue window), the disc is seen in an abnormal position, posteriorly in relation to the condyle (white arrow). D, In maximal mouth-open position (soft-tissue window), a soft-tissue mass resembling an adhesion is seen between the articular surfaces (arrows).
Table 3. timmary of Direct 8rglttal CT Findings Regarding the Disc (21 TMJs) Position of the disc Normal position Situated anteriorly Situated posteriorly Not seen Function of the disc Normal function Abnormal function Anterior displacement Anterior displacement Not seen Adhesions
12 6
1 2
with reduction without reduction
8 11 4 3 2 8
onance imaging (MRI), CT is the only noninvasive modality that can show changes of the position and function of the disc without contrast medium.3*12*13 Few reports are available on the TMJ disc in patients with mandibular condylar process fractures,5 but the present results suggest that disturbances in the position and function of the articular disc may be more common than was earlier anticipated, and speak in favor of using CT scanning more often to evaluate changes in TMJs after condylar process fractures. Furthermore, soft-tissue changes resembling adhesions are also detectable by CT (Table 3). The patient whose fractured condyle is seen in Fig-
1262
RADIOGRAPHIC
AND CT IN CONDYLAR PROCESS FRACTURES
FIGURE 3. Direct sagittal CT of the fractured mandibular condylar process showing anterior disc displacement with reduction. A, In mouth-closed position (soft-tissue window), the disc is situated anteriorly in relation to the condyle (white arrow). B, In maximal mouth-open position, the disc is in a reduced normal position posterior to the condyle (arrow). Normal condylar excursion is seen. Insertion of the lateral pterygoid muscle (arrowheads).
ure 4 had severely and continual pain The TMJ was later adherent disc and
limited mouth-opening capacity in the region of the right TMJ. exposed surgically and a totally partially fibrous ankylosis were
found. In addition to these features, changes in the size and density of the masticatory muscles . ,have been observed in CT scans of such patients.” It can be concluded that CT is able to reveal bony
FIGURE 4. A, Coronal CT of the right and left TMJs of a patient with severely limited mouth opening. The fractured condyle (on the right) is turned medially and a lateral osteophyte is seen (arrow). B, Direct sagittal CT of the same TMJ. The condyle is situated anteriorly against the articular tubercle in the mouth-closed position (bone window). C, The disc is seen posterior to the condyle (white arrow) (soft-tissue window). D, In maximal mouth-open position (bone window), the condyle has moved just a little.
1263
AMIL J. GERLOCK JR
Table 4.
Main CoronalCT Findings(21 TMJs) N
Condyle turned medially Deformation of the condyle Shortening of the condylar neck Erosion Flattening Sclerosis
12 4 4 5 3
1
condylar changes following fractures, as well as changes in relation of the condyle to the mandibular fossa, more exactly than conventional radiographic examinations. The direction of displacement of the fractured condyle, both anteroposteriorly and mediolaterally, is also seen better by CT than by conventional radiographs. Changes in the position and function of the disc are not seen in conventional radiographs without contrast medium, but are illustrated by CT. Magnetic resonance imaging may complement CT in the future for the diagnosis of disc dysfunction and other structural changes in the TMJ. References 1. Rowe NL, Williams JLC: Maxillofacial Injuries, vol I. New York, NY, Churchill Livingstone, 1985 2. Ekerdal 0: Tomography of the temporomandibular joint: Correlation between tomographic image and histologic
sections in a three-dimensional system. Acta Radio1 329:1, 1973 (suppl) 3. Raustia AM, Pyhtinen J, Virtanen KK: Examination of the temporomandibular joint by direct sagittal computed tomography. Clin Radio1 36:291, 1985 4. Wegener OH, Balan EH, Bier J: Das Computertmogramm zur Beurteilung des Kiefergelenkes. Dtsch Z MundKiefer-Gesichts-Chir 2:30, 1978 5. Christiansen EL, Thompson JR, Hasso AN: CT evaluation of trauma to the temporomandibular joint. J Oral Maxillofac Surg 45:920, 1987 6. Fujii N, Yamasiro M: Computed tomography for the diagnosis of facial fractures. J Oral Surg 39:735, 1981 7. Htils A, von Ehrlich V, Haase S, et al: Computertomographie des frakturierten Unterkiefergelekfortsatzes. Dtsch Zahnartzl Z 38:333, 1983 8. Davis WM Jr: An interesting condylar fracture revealed by use of computed tomography. Oral Surg 67:3 1, 1989 9. Raustia AM, Pyhtinen J: Computed tomography of the masticatory system-A review. Comput Med Imaging Graph 12:97, 1988 10. Stoker DJ: Skeletal disorders of metabolic and endocrine origin, in Sutton D (ed): A Textbook of Radiology and lmaging (ed 3). New York, Churchill Livingstone. 1980. p 166 11. Raustia AM, Pyhtinen J: Morphology of the caput mandibulae and mandibular fossa as seen by computed tomography. J Prosthet Dent 63:77, 1990 12. Raustia AM, Pyhtinen J: Direct sagittal computed tomography as a diagnostic aid in the treatment of an anteriorly displaced temporomandibular joint disc by splint therapy. J Craniomandibular Practice 5:240, 1987 13. Schellehas KP, Wilkes CH, Fritts HM, et al: Temporomandibular joint: MR imaging of internal derangements and postoperative changes. AJNR 8:1093, 1987 14. Oikarinen KS, Raustia AM, Pyhtinen J: CT of main masticatory muscles after mandibular condyle fracture. J Dent Res 68: 1003, 1989 (IADR abstr 1094)
J Oral MaxillofacSurg 46:1X+1264.1990
Discussion Conventional Radiographic and Computed Tomographic Findings in Cases of Fracture of the Mandibular Condylar Process Amil J. Gerlock Jr, MD University of Texas Medical School, Hermann Houston
Hospital,
As stated by these authors, “the aim of the present study was to compare findings related to fractures of the mandibular condylar process as seen in conventional radiographs and computed tomography.” They concluded “that CT is able to reveal bony condylar changes following fractures, as well as changes in relation of the condyles to the mandibular fossa, more exactly than conventional radiographic examination.” This does not represent a new concept or come as any great surprise. Furthermore, these authors performed computed tomography (CT) on 16 patients with 21 fractured condylar processes an average of 32 months after the injury. The indication for CT was temporomandibular joint (TMJ)
problems. From these data, the authors suggest that disturbances in the position and function of the articular disc from trauma may be more common than was earlier anticipated. Again, this comes as no surprise. Previous reports have identified trauma as a major antecedent of TMJ derangement. ‘-I3 This study would have been more informative if it focused on which imaging modalities to use and when to use them. The increased interest in TMJ dysfunction in the past 3 to 5 years has produced a flurry of reports in the literature concerning a wide variety of imaging modalities. These include plain radiography, tomography, arthrography, CT, magnetic resonance imaging (MRI) and radionuclide imaging. Because all of these examinations cannot be used, imaging algorithms should be developed that allow early diagnosis of TMJ internal derangements to be made and corrected before they produce progressive joint degeneration and clinical disability. Presently, early imaging with MR (or arthrography if MRI cannot be performed) and TMJ radiographytomography have been advocated to assess the type and extent of injury to the TMJ after injury.i4 Perhaps early
