schimming, eckelt e kittner (1999) the value of coronal computer tomograms in fractures of the...

Fractures of the mandibular condylar process as a resultof direct or indirect trauma to the mandible play a majorrole in maxillofacial traumatology. They account for21% to 52% of all mandibular fractures.1 No other frac-ture in the maxillofacial region has been so controver-sial in the literature with respect to classification, diag-nosis, and therapeutic management. More than 80papers relating to this injury have been published inEnglish during the last 50 years.2 Different surgicalprocedures using functionally stable osteosynthesismethods and nonsurgical strategies have beendescribed,3-12 and distinct classification systems havebeen suggested.13,14

In our department, treatment strategy is based on theclassification of Spiessl and Schroll.13 All fractures inchildren less than 12 years of age are at first managed

conservatively and subsequently treated functionallywith orthognathic devices, in accordance with recom-mendations in numerous studies.11,15-17 However, thechoice of therapeutic management in adults is contro-versial. Indications and contraindications for varioustreatment modalities have been described by Zide andKent.18 In our department, all fractures involvingdislocation of the condyle and angulation (displace-ment) of the condyle of more than 30 degrees aretreated with open reduction through use of a functionalstable lag screw osteosynthesis system described byEckelt.6 Diacapitular (sagittal/intraarticular) fracturesof the mandibular condyle are treated either conserva-tively or with pin fixation. Fractures with angulationsof less than 30 degrees are treated conservatively andsubsequently treated functionally.

The recent expansion of surgical treatment fordislocated fractures of the mandibular condyledescribed in the literature1,19 should rely on preciseand careful preoperative clinical and radiologicassessment. Clinical signs such as jaw deviation andlimitation during mouth opening, changes in occlu-sion, and extraoral swelling of the preauricular region

632

The value of coronal computer tomograms in fractures of themandibular condylar processRonald Schimming, MD, DDS,a Uwe Eckelt, MD, DDS, PhD,b and Thomas Kittner, MD,cDresden, GermanyUNIVERSITY OF DRESDEN

Objective. A prospective investigation designed to compare the diagnostic accuracy of conventional panoramic and pos-teroanterior mandibular radiographs with that of coronal computed tomography scans in cases of fracture of the mandibularcondylar process was conducted.Study design. In all, 182 patients with a total of 249 fractures (some unilateral and some bilateral) of the mandibular condylereceived conventional radiographs and coronal computed tomography scans as diagnostic procedures. The ability of theseprocedures to detect and correctly classify these fractures was determined, and their importance for therapeutic decision-making is described.Results. All clinically identified fractures were detected by means of both conventional and computed tomography imaging.However, only computed tomography scanning could correctly classify high condylar neck fractures.Conclusions. Especially in cases of high condylar neck fracture, coronal computed tomography scans were more useful thanconventional radiographs in the determination of type of condylar fracture so that a correct treatment decision could be made.(Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1999;87:632-9)

aResearch Assistant, Department of Oral and Maxillofacial Surgery.bProfessor and Head, Department of Oral and Maxillofacial Surgery.cResearch Assistant, Department of Diagnostic Radiology.Received for publication July 23, 1998; returned for revision Sept 28,1998; accepted for publication Jan 10, 1999.Copyright 1999 by Mosby, Inc.1079-2104/99/$8.00 + 0 7/16/97858

ORAL AND MAXILLOFACIAL RADIOLOGY Editor: Sharon L. Brooks

ORAL SURGERY

ORAL MEDICINE

ORAL PATHOLOGY

Vol. 87 No. 5 May 1999

can be indicative of unilateral or bilateral fractures ofthe condylar process.20 Panoramic radiographs(OPGs) and posteroanterior mandibular radiographs(PAMRs) are the conventional forms of radiographythat are used. They provide an overall view of thefractured mandible and indicate displacement of thefractured condylar process in the anteroposterior andlateromedial directions. Two different goals must beachieved with these radiographs: first, the diagnosisof a condylar fracture must be confirmed; second, thefracture must be described and classified to determinewhether surgery is indicated and to choose the bestosteosynthesis technique or select a conservativealternative.

Conventional radiodiagnosis (with OPGs andPAMRs) is helpful in describing the position of thecondylar process fracture. However, in our experiencesconventional radiodiagnosis has not always allowedcorrect assessment of fracture position. This has espe-cially been true for some cases of high condylar neckfracture and diacapitular fracture in which additionalfracture lines and definitive classification of the frac-ture type could not be determined. In such cases,coronal computed tomography (CT) is recom-mended.21-25 These findings were confirmed by aninvestigation of 40 patients with 46 fractures of themandibular condylar process.26 However, only 16 ofthose patients received additional examinations withCT. The CT scans were done between 9 and 106 weeksafter the primary injury. No further investigationcomparing conventional radiodiagnosis and coronalCT scan in a large number of fractures of themandibular condylar process has been done to date.

The purpose of this prospective investigation wasto compare conventional radiographs (OPGs andPAMRs) and coronal computed tomographs withrespect to diagnostic precision for the sake of inves-tigating their effects on the analysis of those dimen-sions that determine the indication for surgical treat-ment (condylar fragment orientation, course of thefracture line, angulation degree, and dislocation ofthe condyle). Our hypothesis was that coronal CTscans may improve the diagnosis of fractures of themandibular process and thus lead to more exactanalyses of fracture lines and fracture types, therebyleading to more effective therapy.

MATERIAL AND METHODSFor this prospective study, we examined 182 patients

who between January 1992 and December 1997 hadexperienced various injuries that resulted in unilateralor bilateral fractures of the mandibular condyle (n =249 fractures). All patients were treated consecutivelyin our department. The inclusion and exclusion criteriafor this investigation were as follows:

Inclusion criterion: Clinical diagnosis of a unilateralor bilateral condylar neck fracture based on clinicalexamination20

Exclusion criterion: Contraindications for directcoronal CT scanning of the condylar process(injuries of the cervical spine or severe intracranialinjuries). Thirty-one patients who were treatedduring the same period for unilateral or bilateralcondylar neck fractures did not fulfill the studyprotocol because of the severity of their injuries.

For every patient in the study, the following radio-

ORAL SURGERY ORAL MEDICINE ORAL PATHOLOGY Schimming, Eckelt, and Kittner 633Volume 87, Number 5

Fig 1. Distribution of fracture frequency (n = 249).

logic examinations were carried out: (1) OPG with anOrthophos Plus (Siemens, Germany); PAMR (caudaleccentric posteroanterior skull examination withmaximum opening of the mouth) with a Super 50 CP-D (Philips). The technical data of investigation (kilo-voltages, milliamperages, and time) were dependent onpatient age and gender and were standardized for expo-sures. The specific doses were 8-30 mGy (surfacedose) for the OPG and 1.3-10 mGy for the PAMR. Allradiographs were of acceptable quality. In addition, adirect coronal CT scan of each fracture region wasmade with a Tomoscan SR 7000 (Philips). For thisstudy, reconstruction of coronal cuts from axial scanswas not done because a thinner slice (ie, a higher radi-ation dose) would then have been necessary.27

The following parameters were used for the coronalCT scan: mode, helical; kV, 120; mA, 200; field ofview, 210; slice thickness, 3 mm; table feed, 3 mm;reconstruction index increment (RI), 3 mm; specificdose, 80-90 mGy.

Two independent observers (one for each method)interpreted the results of the conventional radiologic

examinations and the coronal CT scans. In every case,the conventional investigation was done first. No infor-mation about the results from the conventional radi-ographs was available to the CT observer before thecoronal CT scan was assessed.

All fractures of the mandibular condyle werecompared with respect to frequency and localitythrough use of the classification system described bySpiessl and Schroll13 in 1972. They distinguish thefollowing fracture types:

Spiessl I: fracture without angulation and dislocationSpiessl II: fracture at the basis of the condylarprocess with angulation

Spiessl III: fracture at the condylar neck with angu-lation (high condylar neck fracture)

Spiessl IV: fracture at the basis of the condylarprocess with dislocation

Spiessl V: fracture at the condylar neck with disloca-tion (high condylar neck fracture)

Spiessl VI: diacapitular fracture (intraarticular).The term diacapitular fracture was confirmed by

Rasse et al in 1993.28 They performed an anatomical

634 Schimming, Eckelt, and Kittner ORAL SURGERY ORAL MEDICINE ORAL PATHOLOGYMay 1999

Fig 2. Analysis of fracture lines (n = 249).

Table I. Accuracy of conventional radiologic examinationsType of fracture*

Spiessl I Spiessl II Spiessl III Spiessl IV Spiessl V Spiessl VI

Detection (%) 100 100 100 100 100 100Correct classification (%) 100 100 70 100 75 100*Fracture classification according to Spiessl and Schroll.13

study in which the temporomandibular joints (TMJs) of20 human cadavers were sectioned to control the clinicalfindings. All fractures studied proved to be intracapsularand extracapsular and always involved the insertion ofthe lateral pterygoid muscle at the mandibular condyle.

To ascertain whether there were any importantdifferences among the different radiologic examina-tions, the ability of conventional techniques both todetect and to classify condylar fractures was deter-mined. In all cases, the evaluation of detection wasbased on the clinical examination and clinical diag-

nosis of a unilateral or bilateral condylar neck fracture.The gold standard for fracture classification was thecoronal CT image.

RESULTSIn all, 182 patients with a total of 249 fractures of the

mandibular condyle (some unilateral, some bilateral)entered our study. The average age of the 136 male and46 female patients was 28.1 years; the subjects rangedin age from 12 to 82 years. There were 67 patients withbilateral fractures and 115 patients with unilateral frac-tures. Fig 1 shows the frequency of the distribution of


Fig 3. OPG and PAMR show 4-fold mandibular fracture.

Fig 4. Coronal CT scan shows bilateral fracture of mandibularcondyle in patient of Fig 3.

Fig 5. OPG (A) and PAMR (B) show unilateral (right)condylar neck fracture.

A

B

fractures according to coronal CT scan. The distribu-tion was as follows: Spiessl I fractures, 8.0%, Spiessl IIfractures, 32.1%; Spiessl III fractures, 3.2%; Spiessl IVfractures, 16.9%; Spiessl V fractures, 12.2%; SpiesslVI fractures, 27.6%.

Using the coronal CT scans, we determined that mostfractures (81.5%) exhibited oblique fracture lines (Fig2). This is of importance for all types of fractures of thecondylar process. In high fractures of the condylarneck (Spiessl III, V, and VI), horizontal fracture lineswere revealed in 5.6% of the cases.

Conventional radiologic examinations (OPGs andPAMRs) detected all clinically diagnosed fractures ofthe mandibular condylar process. However, as shownin Table I, conventional radiologic examinations did

not correctly classify all fractures, particularly in thecase of high condylar neck fractures (Spiessl III andV). In 18 cases (6 Spiessl III and 12 Spiessl V) inwhich the fractures had been classified by conven-tional radiology, the oblique fracture line was firstdiagnosed in the coronal CT scan. The fracture lineled to an inclusion of the condyle of the mandible andthus to a change in the fracture classification and thetherapeutic procedure. The diagnosis and fractureclassification by coronal CT scan was confirmedintraoperatively in each patient who received openfracture reduction. Furthermore, the coronal CT scandisplayed a better overview of the fracture area and


Fig 6. Coronal CT scan shows unilateral fracture of rightmandibular condyle in patient of Fig 5.

Fig 7. OPG and PAMR show unilateral (right) condylar neckfracture.

Fig 8. Coronal CT scan shows unilateral fracture of rightmandibular condyle in patient of Fig 7.

Fig 9. OPG and PAMR show bilateral condylar neck fracture.

revealed additional fracture lines, particularly in casesof high condylar neck fracture (Spiessl III and V) anddiacapitular fracture (Spiessl VI). A clinical exampleof this is shown in Figs 3 and 4, which illustrate thecase of a patient with a 4-fold mandibular fracture,including a Spiessl II fracture on the right side and aSpiessl V fracture on the left side. Whereas conven-tional radiodiagnosis (Fig 3) for the deep fracture ofthe condylar process clearly indicated surgicaltherapy, it was nonetheless insufficient for the highfracture of the condylar neck. Only the coronal CTscan (Fig 4) revealed the exact location of the fracturefragment, thereby ruling out an additional fracture ofthe left condyle.

A unilateral condylar neck fracture is displayed inFigs 5 and 6. Conventional radiographs (Fig 5) allowedthe diagnosis of a high condylar neck fracture (SpiesslVI) on the right hand side, but only the coronal CT scan(Fig 6) could give the indication for subsequentsurgical therapy (pin fixation) for this Spiessl VI frac-ture. Figs 7 and 8 show a unilateral fracture (SpiesslVI) of the right condylar neck. The coronal CT scan(Fig 8) revealed a comminuted fracture of the condyle,whereas conventional radiographs (Fig 7) only allowedthe diagnosis of a Spiessl VI fracture. In this case, thecoronal CT scan clearly indicates conservative func-tional fracture treatment. Figs 9 and 10 show a bilateralcondylar neck fracture, with a Spiessl VI fracture onthe left side and a Spiessl II fracture on the right side.The conventional radiographs (Fig 9) indicated theneed for surgical treatment of the Spiessl II fracture(lag screw osteosynthesis); the coronal CT scan (Fig10) revealed additional information that was necessaryfor pin fixation of the fracture on the right side.

DISCUSSIONCT is a suitable method of diagnosing high

condylar process fractures and other facial fracturesnot seen in conventional radiographs.21-25 It allowsvisualization of anatomical structureseg, corticalbone loss, sclerosis, and changes in joint morphologyand condyle position in the mandibular fossafreeof superimposition, providing the viewer with 3-dimensional information if sequential images arereconstructed (either mentally or pictorially by thecomputer). The usefulness of CT scans in follow-upinvestigations of fractures of the mandibular condyleand for investigation of morphologic changes hasbeen described.26,29-33

Comparison of the results of conventional radi-ographs (OPGs and PAMRs) and coronal CT scans of249 fractures of the mandibular condylar process

showed that coronal CT scans should be performed inall cases of high fracture of the mandibular condyle.In 18 cases of this fracture type, the fracture line wasexactly determined only by coronal CT scan. The newfracture classification led to a new therapeuticapproach in each of these cases. Instead of lag screwosteosynthesis, either conservative functional treat-ment or pin fixation of the fracture was undertaken.

Coronal CT scans should be performed in cases ofdiacapitular fracture of the mandibular condylebecause additional fractures of the condyle (Fig 4)were found only in coronal CT scans. The so-calledchip fracture of the mandibular condyle was firstdescribed by Avrahami and Horowitz34 in 1984.However, the authors could not find the describedfracture by means of conventional radiographicprocedures. Moreover, in cases of diacapitular frac-ture the coronal CT scan allows an exact descriptionof the TMJ and the fractured fragments. The CT scanis a requirement for open reduction of this fracturetype and subsequent fixation of the fracture withpins. In the case of conservative functional treatment,the CT scan may give additional information thatwould be useful in the planning of subsequent func-tional treatment.

Despite their disadvantages, conventional radi-ographs allowed accurate diagnosis of low condylarfractures. In our opinion, a coronal CT scan should bedone in all cases involving suspected fractures in theTMJ area, including high fractures of the condylarneck, so that all information necessary for treatmentplanning can be gathered.


Fig 10. Coronal CT scan shows bilateral condylar neck frac-ture in patient of Fig 9.

mandibular condylar process. J Craniomaxillofac Surg1992;20:348-53.

9. MacArthur CJ, Donal PJ, Knowless J, Moore HC. Open reduc-tion-fixation of mandibular subcondylar fractures: a review.Arch Otolaryngol Head Neck Surg 1993;119:403-6.

10. Walker RV. Condylar fractures: non-surgical management. JOral Maxillofac Surg 1994;52:1185-8.

11. Holl MB. Condylar fractures: surgical management. J OralMaxillofac Surg 1994;52:1189-92.

12. Ziccardi VB, Schneider RE, Kummer FJ. Wurzburg lag screwplate versus four-hole miniplate for the treatment of condylarprocess fractures. J Oral Maxillofac Surg 1997;55:602-7.

13. Spiessl B, Schroll K. Gesichtsschdel. In: Ningst H, editor.Spezielle Frakturen- und Dislocationslehre. Stuttgart and NewYork: Thieme; 1972. Bd. I/1.

14. Lindahl L. Condylar fractures of the mandible, I: classficationand relation to age, occlusion and concomitant injuries of teethsupporting structures and fractures of the mandibular body. Int JOral Surg 1977;6:12-21.

15. Chalmers J Lyons Club (Members of). Fractures involving themandibular condyle: a post treatment survey of 120 cases. J OralSurg 1947;5:45-73.

16. Dahlstrm L, Kahnberg KE, Lindahl L. Fifteen year follow upon condylar fractures. Int J Oral Maxillofac Surg 1989;18:18-23.

17. Leake D, Douglas J, Habal MB, Murray JE. Long term followup of fractures of the mandibular condyle in children. PlastReconstr Surg 1971;47:127-31.

18. Zide MF, Kent JN. Indications for open reduction of mandibularcondyle fractures. J Oral Maxillofac Surg 1983;41:89-98.

19. Eckelt U, Hlawitschka M, Feller KU, Schimming R. Comparativestudies on the treatment of fractures of the mandibular jointprocess. In: Ravindranathan R, editor. Maxillofacial surgery. Vol.3. Bologna: Monduzzi Editore; 1997. p. 379-83.

20. Rowe NL, Williams JLC, editors. Maxillofacial injuries. Vol. I.New York: Churchill Livingstone; 1985.

21. Fujii N, Yamasiro M. Computed tomography for the diagnosis offacial fractures. J Oral Surg 1981;39:735-41.

22. Davis WM Jr. An interesting condylar fracture revealed by useof computed tomography. Oral Surg Oral Med Oral Pathol1989;67:31-2.

23. Zller J, Mende U, Eitel B. Diagnosis of dislocation-fracture ofmandibular condyle. ZWR 1989;98:771-3.

24. Yamaoka M, Furusuwa K, Iguchi K, Tanaka M, Okuda D. Theassessment of fracture of the mandibular condyle by use ofcomputerized tomography: incidence of sagittal split fracture.Br J Oral Maxillofac Surg 1994;32:77-9.

25. Laine FJ, Conway WF, Laskin DM. Radiology of maxillofacialtrauma. Curr Probl Diagn Radiol 1993;22:145-88.

26. Raustia AM, Phytinen J, Oikarinen KS, Altonen M.Conventional radiographic and computed tomographic findingsin cases of fracture of the mandibular condylar process. J OralMaxillofac Surg 1990;48:1258-62.

27. Drexler D, Panzer W, Widemann L, Williams G, Zanki M. DieBestimmung von Organdosen in der Rntgendiagnostik. Berlin:H. Hoffmann; 1985.

28. Rasse M, Koch A, Traxler H, Mallek R. Der Frakturverlauf vondiakapitulren Frakturen der Mandibula: eine klinische Studiemit anatomischer Korrelation. Z Stomatol 1993;90:119-25.

29. Avrahami E, Frishman E, Weiss-Peretz J, Horowitz I. Computedtomography of healing condylar fractures with some clinicalcorrelations. Clin Radiol 1993;47:269-73.

30. De Bont LG, van der Kuijl B, Stegenga B, Vencken LM, BoeringG. Computed tomography in differential diagnosis of temporo-mandibular joint disorders. Int J Oral Maxillofac Surg1993;22:200-9.

31. Choi BH. Comparison of computed tomography imaging beforeand after functional treatment of bilateral condylar fractures inadults. Int J Oral Maxillofac Surg 1996;25:30-3.

32. Kahl B, Fischbach R, Gerlach KL. Temporomandibular joint


When the problem of radiologic diagnosis is beingdiscussed, it should be mentioned that some patientswith maxillofacial injuries receive these injuries duringmultitraumas, and direct coronal CT scans thus some-times cannot be performedeg, when there arecervical spine injuries or intracranial injuries accompa-nied by high intracranial pressure. In these cases, axialCT scans are usually performed to obtain informationabout intracranial injuries. A coronal reconstruction ofaxial CT scans should be done to gather the informa-tion necessary for subsequent treatment in the case of aclinically diagnosed condylar neck fracture.

Any comparison of CT and conventional radiog-raphy (OPGs and PAMRs) with respect to radiationrisk is problematic, but it would appear from theliterature that the risk is 1 order, if not 2 orders, ofmagnitude greater with the former.35,36 Therefore,the clinician must weigh these risks against the bene-fits in diagnostic yield in making the therapeuticdecision.

To reduce the radiation dose, a coronal CT scanwithout additional conventional radiographs shouldbe performed in cases of clinically diagnosed iso-lated unilateral or bilateral condylar neck fracture. Incases of combined fracture of the mandible, conven-tional radiographs should be done first; coronal CTscanning should follow only when a high condylarneck fracture is likely. A coronal reconstruction ofaxial CT scans is recommended in cases of panfacialfracture for the sake of obtaining the equivalentinformation for subsequent midface and skull basereconstruction.

REFERENCES1. Silvennoinen U, Iizuka T, Lindquist C, Oikarinen K. Different

patterns of condylar fractures: an analysis of 382 patients in a 3year period. J Oral Maxillofac Surg 1992;50:1032-7.

2. Mitchell DA. A multicentric audit of unilateral fractures of themandibular condyle. Br J Oral Maxillofac Surg 1997;35:230-6.

3. Pape HD, Haustein H, Gerlach KL. Chirurgische Versorgung derGelenkfortsatzfrakturen mit Miniplatten: Indikationen - Technik- erste Ergebnisse und Grenzen. Fortschr Kiefer GesichtsChir1980;25:81-7.

4. Petzel JR, Bulles G. Stability of the mandibular condylarprocess after functionally stable traction-screw-osteosynthesis(TSO) with a self-tapping screw-pin. J Maxillofac Surg1982;10:149-54.

5. Habel G, ORegan B, Hidding J, Eissing A. A transcoronoidalapproach of fractures of the condylar neck. J CraniomaxillofacSurg 1990;18:348-51.

6. Eckelt U. Zugschraubenosteosynthese bei Untekiefergelenkfort-satzfrakturen. Dtsch Z Mund Kiefer GesichtsChir 1991;15:51-7.

7. Stewart A, Bowerman JE. A technique for control of thecondylar head during open reduction of the fractured mandibularcondyle. Br J Oral Maxillofac Surg 1991;49:989-95.

8. Krenkel C. Axial anchor screw (lag screw with bioconcavewasher) or slanted-screw for osteosynthesis of fractures of the

morphology in children after treatment of condylar fractureswith functional appliance therapy: a follow-up study usingcomputed tomography. Dentomaxillofac Radiol 1995;24:37-45.

33. Dahlstrm L, Lindvall AM. Assessment of temporomandibularjoint disease by panoramic radiography: reliability and validity inrelation to tomography. Dentomaxillofac Radiol 1996;25:197-201.

34. Avrahami E, Horowitz I. Chip fracture of the mandibularcondyle. Head Neck Surg 1984;6:978-81.

35. Huda W, Sandison GA. The use of the effective dose equivalentas a risk parameter in computed tomography. Br J Radiol1986;59:2136-8.

36. Gibbs SJ, Pujol A, McDavid WD, Welander U, Tronje G. Patientrisk from rational panoramic radiography. DentomaxillofacRadiol 1988;17:25-32.

Reprint requests:Uwe Eckelt, MD, DDS, PhDDepartment of Oral and Maxillofacial SurgeryUniversity of DresdenFetscherstr. 74D-01307 DresdenGermany


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