the comprehensive aocmf classiﬁcation system: mandible ... · head & neck surgery, geisinger...

The Comprehensive AOCMF ClassificationSystem: Mandible Fractures- Level 2 TutorialCarl-Peter Cornelius, MD, DDS1 Laurent Audigé, DVM, PhD2,3 Christoph Kunz, MD, DDS4

Randal Rudderman, MD, FACS5 Carlos H. Buitrago-Téllez, MD6,7 John Frodel, MD, FACS8

Joachim Prein, MD, DDS4

1Department of Oral and Maxillofacial Surgery, Ludwig MaximiliansUniversität, München, Germany

2AO Clinical Investigation and Documentation, AO Foundation,Düebendorf, Switzerland

3Research and Development Department, Schulthess Clinic, Zürich,Switzerland

4Clinic for Oral and Craniomaxillofacial Surgery, University HospitalBasel, Basel, Switzerland

5Plastic, Reconstruction and Maxillofacial Surgery, Alpharetta, Georgia6 Institute of Radiology, Zofingen Hospital, Zofingen, Switzerland7Hightech Research Center for CMF Surgery, University of Basel, Basel,Switzerland

8Division of Facial Plastic Surgery, Department of Otolaryngology-Head & Neck Surgery, Geisinger Medical Center, Danville,Pennsylvania

Craniomaxillofac Trauma Reconstruction 2014;7(Suppl 1):S15–S30

Address for correspondence Carl-Peter Cornelius, MD, DDS,Department of Oral and Maxillofacial Surgery, Ludwig MaximiliansUniversität, Lindwurmstrasse 2A, D-80337 München, Germany(e-mail: [email protected]).

The level 1 as the most elementary CMF classification servesto identify the presence ofmandibular fractures,1 irrespectiveof their description in location, number, pattern, or morphol-ogy. The level 2 classification system sets minimal standardsfor the assessment and documentation of CMF fractures,allowing the description of the fracture topography within

defined regions based on the examination of diagnosticX-rays and/or CT imaging. This tutorial focuses on noncon-dylar mandibular fractures. It is organized in a sequence ofsections starting with the imaging anatomy and its nomen-clature, followed by a description of the classification systemwith illustrations of the topographical mandibular regions.

Keywords

► fracture classification► mandible► anatomic regions► transition zones► confined fractures

Abstract This tutorial outlines the details of the AOCMF image-based classification system forfractures of the mandible at the precision level 2 allowing description of theirtopographical distribution. A short introduction about the anatomy is made. Mandibu-lar fractures are classified by the anatomic regions involved. For this purpose, themandible is delineated into an array of nine regions identified by letters: the symphysis/parasymphysis region anteriorly, two body regions on each lateral side, combined angleand ascending ramus regions, and finally the condylar and coronoid processes. A precisedefinition of the demarcation lines between these regions is given for the unambiguousallocation of fractures. Four transition zones allow an accurate topographic assignmentif fractures end up in or run across the borders of anatomic regions. These zones aredefined between angle/ramus and body, and between body and symphysis/para-symphysis. A fracture is classified as “confined” as long as it is located within a region,in contrast to a fracture being “nonconfined” when it extents to an adjoining region.Illustrations and case examples of mandible fractures are presented to become familiarwith the classification procedure in daily routine.

Copyright © 2014 by AO FoundationAOCMFClavadelerstrasse 87270 DavosSwitzerlandTel: +41 44 200 24 20.

DOI http://dx.doi.org/10.1055/s-0034-1389557.ISSN 1943-3875.

Tutorial Article S15

Dow

nloa

ded

by: T

hiem

e V

erla

gsgr

uppe

. Cop

yrig

hted

mat

eria

l.

mailto:[email protected]

http://dx.doi.org/10.1055/s-0034-1389557

http://dx.doi.org/10.1055/s-0034-1389557

Rules for fracture location and coding are defined alongwith aseries of case examples with clinical imaging. Finally, thedesign of this classification system is discussed. The moredetailed level 3 classification system (dentition, atrophy,fracture morphology) is presented in a subsequent paper.2

Anatomical and Diagnostic ImagingConsiderations

Current CT imaging modalities (helical or cone beam scans)are capable of providing detailed information on the internaland external anatomic bony features in two-dimensionalsuperimposed transparent views, in multiplanar cross-sec-tional slices,3 or in three-dimensional (3D) visualization aftervolume or surface rendering.4 3D outer surface displays of theskeleton are considered as the modern correspondence tonormal macroscopic textbook anatomy or surgical exposure.They commonly serve as reference for a differentiated label-ing of the topography and structural elements using consen-sus-based nomenclature.5 In the mandible, internalstructures such as the mandibular canal or the tooth rootsare utilized as additional markers to relate to regional topog-raphy in addition to the external features such as the jugaalveolaria.

Panoramic X-ray views are a reliable mode for an overallscreening of the mandible for pathology and in particularfractures. The outstretched images have a great impact on thevisual perception of surgeons. The unrolled display, however,does not reflect the true curvature and shaping of themandible, which can trouble the transfer into surgery, inparticular with a varying magnification factor. Nevertheless,schemes of the mandible in panoramic style have become thepreeminent iconography to describe and document fracturelines/zones in clinical work-up, textbooks, and scientificarticles, what has been pursued in this tutorial.

Level 2 Mandibular Fracture ClassificationSystem

The level 2 focuses on the topographic location of fractureswithin the anatomical regions of themandible. According to theusual course of fractures, the mandibular regions are arrangedin a vertically oriented framework, which relates to the toothroot positions of the canines and the thirdmolars (►Fig. 1). Theboundaries of these regions are defined as follows.

Symphysis/Parasymphysis RegionThe symphysis/parasymphysis region is the single centralunit of the mandibular arch. Its lateral edges are determinedby the roots of the lower canines and thus this regionmatcheswith the intercanine bone portion. For the purpose of thisclassification, we will refer to it as the symphysis region.

Two anterior transitional zones (numbered 1 in ►Fig. 1)are defined along the contours of the canine roots as verticalstrips in the width of the adjacent interdental spaces. In thecase of an edentulous mandible, the anterior transitionalzone is located �5 mm (¼ width of a premolar) in front ofthe mental foramen. These anterior transitional zones are

defined to facilitate the location of fractures within thesymphysis region depending on their extension into thesezones or across to an adjoining body region (►Fig. 2). If afracture within the symphysis region extends into one ante-rior transitional zone without crossing it, the fracture isconsidered confined within the symphysis region.

Mandibular Body RegionThemandibular body refers to each of the lateral bony regionsbetween the canines and the angle. In the dentate mandible,the anterior edge of the mandibular body goes through theroot of the lower canines. Thus, the anterior border of thebody is congruent with the anterior transitional zone. Afracture line fully located within the anterior transitionalzone is assigned to the respective body region; however, if itcrosses into the symphysis region, it will be assigned also tothat latter region (►Fig. 2). Two posterior transitional zones(numbered 2 in ►Fig. 1) are defined along the outlines of thethirdmolar roots as vertical strips in thewidth of the crownofthe third molar. In the edentulous mandibular body, theposterior transitional zone must be placed in an approximatemanner to incorporate the retromolar area. The verticalborders of the mandibular body are limited by the anteriorand the posterior transitional zones.

The posterior transitional zones are considered whenlocating fractures within the area between body and theangle/ramus region. A fracture line in a body region extendinginto the posterior transitional zone is considered confined tothe body region. No distinction is made in this classificationhere between anterior and posterior body fractures. Allfracture courses within the mandibular body are equallyclassified as body fractures and check marked accordingly.

Angle/Ramus RegionThe angle region and the ramus region excluding the condy-lar and the coronoid processes are merged into a singleregion. It has an irregular pentagonal shape and extendsfrom a vertical line behind the third molar to the outermandibular angle at the inferoposterior margin, to themandibular notch and the bases of the condylar and thecoronoid process superiorly.

Figure 1 Mandible (91) panorama-style overview with layout ofanatomical regions and transitional zones. Note: Four transitionalzones between adjacent symphysis and body subdivisions (1 ¼ ante-rior transitional zones), and between adjacent body and angle/ramussubdivisions (2 ¼ posterior transitional zones) are defined as de-scribed in the text. Applied rules for classification of fracture locationand continuity across subdivisions are described in ►Fig. 2.

Craniomaxillofacial Trauma and Reconstruction Vol. 7 Suppl. 1/2014

AOCMF Level 2 Classification System for Mandibular Fractures Cornelius et al.S16

Dow

nloa

ded

by: T

hiem

e V

erla

gsgr

uppe

. Cop

yrig

hted

mat

eria

l.

The anterior boundary of the angle/ramus region is congru-ent with the posterior transitional zone; hence, the retromolararea is included within the angle/ramus region. A fracture linefully located within the posterior transitional zone is assignedto the angle/ramus region; however, if it extends into the bodyregion, it is assigned to that region (►Fig. 2).

The superior boundary of the angle/ramus region has agable-shaped configuration with two straight lines divergingfrom the middle of the mandibular notch. These lines delimitthe base of the condylar process and the coronoid process,respectively. Fractures pertaining to the angle/ramus regionextend from the inner angle of the mandible (third molar or

Figure 2 Rules to assign fracture lines within the reach of transitional zones. (A) Fracture entirely located within a transition zone. (B) Fractureextending into the anterior transition zone. (C) Fracture extending into a posterior transition zone. (D) Fracture running across a transition zone.Note: The illustrations were created with the AOCOIAC software.1


AOCMF Level 2 Classification System for Mandibular Fractures Cornelius et al. S17

Dow

nloa

ded

by: T

hiem

e V

erla

gsgr

uppe

. Cop

yrig

hted

mat

eria

l.

retromolar area) or the anterior border of the ramus under-neath the subcoronoid notch to the inferoposterior margin ofthe ramus (i.e., the outer angle).

Coronoid ProcessThe coronoid (muscular process) is the insertion site for thetemporal muscle. The posterior concave border of the sharp-tipped triangular coronoid bone plate coincides with theanterior arc of the mandibular notch. The convex anteriorcrescent-shaped edge of the coronoid ends in the subcoronoidindentation. The base of the coronoid process corresponds toa line passing from the mandibular notch to the subcoronoidindentation.

The coronoid is regarded as fractured only if the coronoidis fully separated from the mandibular ramus. Even if thecourse of the fracture line does not sharply adhere to theboundaries of the coronoid and runs inferiorly into theadjacent angle/ramus region, it is still accounted as a coronoidprocess fracture.

Condylar ProcessThe condylar process is a major region comprising the base,neck, and head subregions. The borderline between the base

of the condylar process and the adjacent angle/ramus isoblique and runs inferiorly and posteriorly from the lowestpoint of the mandibular notch to the masseteric tuberositynotch.6 In a condylar process fracture, the bony continuitymay be lost along this borderline to the ramus; however, if afracture line exits the posterior margin of the ramus belowthe masseteric tuberosity notch, the fracture is allotted to theangle/ramus region. A more detailed description of the sub-regions of the condylar process follows in a separate Level 3tutorial article fractures in this area.6

Confinement—Fractures Located within AnatomicalRegionsTwo fracture patterns are discerned with regard to theiranatomical location within regions:

• “Confined” fracture pattern: the fracture, irrespective of itsmorphology, remainswithin an anatomical region (includ-ing a transition zone) and does not extend into an adjoin-ing region across a transition zone.

• “Nonconfined” fracture pattern: the fracture crosses atleast one transition zone andmay extend over one or moreadjoining region.

Figure 3 Anterior transition zone determination in edentulous mandible. (A) Imaging: Computed tomography scans 3D reformatted, overviewswith location of anterior transitional zone, 3D reformation in detail: anterior and inside (lingual) view, axial, and coronal slices, description:edentulous mandible with parasymphyseal fracture (left). (B) Level 2 code: 91 S. This case example CMTR-91-002 is made available electronicallyfor viewing using the AOCOIAC software at www.aocmf.org/classification. 3D, three-dimensional.



Dow

nloa

ded

by: T

hiem

e V

erla

gsgr

uppe

. Cop

yrig

hted

mat

eria

l.

Fracture Coding and Topographical DistributionAccording to the general scheme of the AO/OTA classificationsystem,7 craniomaxillofacial fractures are assigned with theone-digit code 9. In the CMF system, fractures of themandibleare identified with the two-digit code 91.1 In coding the

fractures according to their location in the level 2 system, eachfractured region is identified by a letter (►Fig. 1):

• S ¼ Symphysis/parasymphysis• B ¼ Body• A ¼ Angle/ramus• C ¼ Coronoid process• P ¼ Condylar process

The letters specifying the involved regions are addedafter the initial 91. The regions are coded in the order fromthe patient’s right side to the patient’s left side. In theoverall fracture code, the small letter “m” (abbreviation for“middle”), or the letter “S” if the symphysis region isfractured, marks the limit between the two sides. Hence,letters specified before and after the “m” or “S” refer to thepatient’s right and left side, respectively. A hyphen sign “-”is inserted in between region letters to indicate that afracture extends into an adjoining region (nonconfined).The hyphen is replaced by a point “.” between two letters toindicate the related regions are involved with separatefractures.

Case Examples

In a series of three case examples, we illustrate the coding of afracture confined within the symphysis (►Fig. 3), a double-fracture pattern confined within body and angle/ramus re-gions (►Fig. 4), and a nonconfined fracture locatedwithin thesymphysis and one body region (►Fig. 5). A range of addi-tional fracture patterns is presented online in a special case

Figure 4 Double fracture. (A) Imaging: Panorama X-ray. Description:Fracture confinedwithin the body region, including the transition zonewiththe symphysis region on the right side, and second fracture located withinthe angle/ramus region on the left side. (B) Level 2 code: 91 B.m.A. This caseexample CMTR-91-015 ismade available electronically for viewing using theAOCOIAC software at www.aocmf.org/classification.

Figure 5 Nonconfined fracture over symphysis and body. (A) Imaging: 3D CT reconstruction. Description: Fracture located across the symphysisand body regions on the right side. (B) Level 2 code: 91 B-S. This case example CMTR-91-013 is made available electronically for viewing using theAOCOIAC software at www.aocmf.org/classification. CT, computed tomography; 3D, three- dimensional.



Dow

nloa

ded

by: T

hiem

e V

erla

gsgr

uppe

. Cop

yrig

hted

mat

eria

l.

appendix as electronic supplement (www.cmf.aofoundation.org/classification).

This coding system allows description of the topographicaldistribution of fractures, such as unilateral or bilateral frac-ture patterns. In accord with the areas of mechanical weak-ness in the mandible, there are some typical topographicfracture site combinations. Fractures in the anterior arc arefrequently associatedwith posterior fracture sites in the angleor in one or both condylar processes. Typical examples forbilateral double fracture are symphysis or body fracturesconjoined with a contralateral condylar process fracture(►Fig. 6A). Another common bilateral fracture is a symphysisfracture combined with an angle/ramus region fracture(►Fig. 6B). It should be noted that a double unilateral fracturemay occur within the body or the ramus/angle region(►Fig. 6C); in the level 2 system, such a pattern is documentedas one fracture. In the level 3 system describing the morphol-ogy of the fracture, it is described as a severe fragmentationpattern.2Other fracture patterns are presented inAppendix 1.

Discussion

There are no natural lines in themandible allowing for a clear-cut distinction of anatomic regions, therefore / or/ that is whya uniformly agreed upon anatomic or surgical terminologydetailing the interregional borders and margins is missing. A

topographic classification of the mandible fractures requiresthe implementation of a conclusive visual framework incombination with written definitions to enable a reliableassignment of injuries.

For the anatomical location of fractures, a set of verticalborderlines divides the mandibular arch into three regions:the symphysis and the body on the left and on the right.Each ramus also consists of three regions (angle/ramus,coronoid process, and condylar process); hence, theentire mandible is conceptualized into nines principaltopographic regions.

Existing classification schemes have sorted mandible frac-tures under multiple aspects by topographic location, dentalocclusion and state of dentition, course, number and overallpattern of fracture lines, relation to masseter, pterygoidmuscle sling, displacement of bone ends, dislocation ofcondylar head out of the fossa, fragmentation and comminu-tion, and bone atrophy or loss and associated soft tissueinjuries within the overlying oral mucosa and/or throughthe facial skin.8–10

For this level 2 mandible fracture classification, onlyformer attempts with topographic implications will be dis-cussed in a chronological literature review (►Table 1).

Topographic classifications of mandible fractures are com-monly used to conduct epidemiologic surveys and to describethe predilection in the anatomical regions depending on the

Figure 6 Level 2 coding examples of mandibular fractures. (A) Level 2 code: 91-A-m-B. Bilateral double fracture: Right angle combined with bodyregion on the left. Both fracture lines are confined to the transitional zones. (B) Level 2 code: 91-P-m-B. Double mandible fracture: Body andcontralateral condylar process. (C) Level 2 code: 91-m-B. Unilateral double mandible fracture within the anterior and posterior body.



Dow

nloa

ded

by: T

hiem

e V

erla

gsgr

uppe

. Cop

yrig

hted

mat

eria

l.

Table 1 Overview of the chronology of mandible fracture classifications pertaining to topography

Author(s) Textbook orJournal article

Database Classification by topography:fracture location, regions, subre-gions, units, zones, areas

Distinctive features

Rowe and Killey17,18

Rowe and Williams47TextbookEmpiric level

638 mandibular frac-tures occurring in 376patients

Two major categories: basal bonevs. nonbasal boneSix topographic regions in basalbone/hemimandible: symphysis,canine, angle and body, ramus,coronoid, condyle

Boundaries between theregions are arbitrary or refer tothe position of teeth

Huelke et al19,20 Journal articleEpidemiologicstudy

319 patients Four major locations/hemimandi-ble: chin, angle–body (betweenmental foramen and gonial angle),subcondylar, “others”

Mental foramen and line ante-rior to ramus as landmarks

Dingman and Natvig8 TextbookEmpiric level

Seven regions/hemimandible:symphysis (¼ intercanine region),body, alveolar process, angle,ramus, condyle process, coronoidprocess

Halazonetis22 Journal article 881 mandibular frac-tures occurring in 560patients

Seven regions/hemimandible:symphysis (lower incisors), canineincluding first premolar, molarregion (second premolar, first andsecond molar), angle regionincluding third molar, ramus, co-ronoid, condyle

Combination of Rowe/Killey,Dingman/Natvig, and land-marks of Huelke et al20

Spiessl and Schroll10 TextbookEmpiric level

Eight regions/hemimandibleBasic scheme based on Dingman/Natvig

Addition of glenoid fossa

Kelly and Harrigan11 Journal articleEpidemiologicstudy

4,317 facial fractures(associated with 3,329mandibular fractures)occurring in 3,324patients

Six categories/hemimandible:symphysis (lower incisors), body(mesial aspect of canine to distalaspect of second molar), angle(retromolar area distal to secondmolar to inferior border of the bodyand posterior border of the ramus),ascending ramus (horizontal frac-tures through anterior and poste-rior borders or vertical from thenotch to inferior mandible border),coronoid, condyle

Arbitrary setup of categories byvertical or oblique borderlinesoriginating from interdentalspaces, no consideration ofalveolar process

Krüger23 TextbookEmpiric level

Fracture localization in sevenregions/hemimandible: symphysis(between canines), canine, body(between canines and angle),angle(¼ third molar region), ramus(between angle and sigmoid/man-dibular notch), coronoid, condyle

Precursor version to AO CMFManual Conception,199826

Spiessl9 Textbook/manualon mandibularfracture careEmpiric level

Based on a medicalthesis (Grätz, 1986,University of Basel,Switzerland)

FLOSA formula/hemimandible (seetext for details): L ¼ localization,L1 ¼ precanine, L2 ¼ canine, L3¼ postcanine, L4 ¼ angular,L5 ¼ supraangulär, L6 ¼ condylarprocess,L7 ¼ coronoid process,L8 ¼ alveolar process

Visually based intuitive schemeof the areas. No verbal definitionof the borderlines. Allocation ofa fracture to a region dependson its position in the basal zone(“determining zone”)

Cooter and David27

David47Journal articleEmpiric level

Presentation of thesystem, one CT scancase example

Graphical facial fracture codingform with 10 bilateral major zoneseach composed of a series of minorzones: MD for mandible consistingof: D (dentoalveolar), S (symphy-seal), B (body), A (angle), R (ra-mus), P (coronoid process), C(condyle)

Visual-based form of the zonesonly. Severity grading using acraniofacial disruption scorebased on the number ofinvolved major zones

Gola et al28 Journal articleEmpiric level

Review of embryologi-cal mandibular subu-nits, anatomiclandmarks,

Three major units and subunits inthe entire mandible:• One body unit consisting of:median and paramedian symphy-sis, rhomboid-shaped body,

Oblique “separation lines” inparallel arrangement:• Canine–foramen• Interbody–ramus

(Continued)



Dow

nloa

ded

by: T

hiem

e V

erla

gsgr

uppe

. Cop

yrig

hted

mat

eria

l.

Table 1 (Continued)




biomechanics, epide-miological surveys

pentagonal angle, dentoalveolarprocess• Two ramus units each consistingof: condylar base, neck, head, andcoronoid

• Interangle–condylar(Interangle–coronoid)

Joos et al29 Journal articleScientific level

76 patients, preopera-tive and clinical follow-up evaluation

Various pre- and intraoperativescore parameters per fracture lineamounting to a possible maximumof 15 points. Contribution of aso-called Anatomic Location Scorefrom 0 to 3 points depending onthe involved region: symphysis¼ 0; premolar region ¼ 1; molarregion ¼ 2; angle/ramus ¼ 3

Presentation of a MandibleFracture (Severity) Score as sumof individual fracture features

Pankratov andRobustova30

PaperEmpiric level

Formula of a theoreti-cal case example

FTLDOSIA formula/hemimandible:F (fracture), T (teeth), L (localiza-tion), D (displacement), O (occlu-sion), S (soft tissue), I (infection),A (associated fractures)Localization: L1–L8: identical toSpiessl32

FLOSA formula reloaded withclinical information—far beyondimaging; leads to overload andinapplicability in routine clinicaluse

Roth et al4 Scientific paperSensitivity/specifici-tyof HCT vs. PT scanstoidentify mandibularfractures

80 patients Division of each hemimandibleinto: anterior mandible;symphysis, parasymphysis, body,posterior mandible, angle, ramus,subcondylar, condylar

Anatomical diagram of themandibular regions visuallybased only, no writtencomments on borderlines

Shetty et al31 Journal articleScientific levelProspective studyStatisticalevaluation

336 patients, assess-ment of contributionof FLOSID items tocomposite MandibularInjury Severity Score(MISS)

FLOSID taxonomy quoting thework of Grätz26:Exchange of A to I and DI ¼ infection; D ¼ dislocation;L ¼ locationLocation areas not completelyidentical to FLOSA. Modification inextent of angle and ramus unit andmodified naming in sequence. Al-location to left and righthemimandible

Conversion of FLOSA intoFLOSID; transfer of these fea-tures into a Mandible Injury Se-verity Score (MISS). Assignmentof fractures over contiguousregions to the predominantlyinvolved basal portion

Follmar et al32 Journal articleEmpiric level

illustrative case of apanfacial fracture

Site-specific radiographic classifi-cation of simple fracture types inthe entire mandible: symphyseal(¼ midline), parasymphyseal(¼ between canines; in edentu-lism ¼ between mental foramina),body (¼ between canine and sec-ond molar), angle, ramus, subcon-dylar, condylar, coronoid

Hierarchically structured uni-form reporting system of com-plex and simple fractures tostreamline communicationamong clinicians

Buitrago-Téllez et al33 (100 patients)Imaging analysis

Division of mandible: two verticalunits (¼ condylar/subcondylarregion, ascending ramus, angle);two lateral horizontal units(¼ lateral mandibular bone anddentoalveolar components); cen-tral mandibular unit (¼ symphysealand parasymphyseal regions)

Tripartite AO/ASIF schemeapplied to mandible compart-ments/units.Sophisticated typecasting,grouping and subgrouping withselected and varying categoriesfor each compartment

Carinci et al34 Journal articleDescriptivestatistics

128 patients Horizontal and vertical subunitgrid/hemimandible: teeth contain-ing alveolar process and basalbone. Six topographical sites:symphysis (¼ interforaminal area),body, angle, ramus, coronoid,condyle

Staging severity using fracturesite and number (single, double,triple) among other variables



Dow

nloa

ded

by: T

hiem

e V

erla

gsgr

uppe

. Cop

yrig

hted

mat

eria

l.

etiology (i.e., motor vehicle accident vs. physical assault) andgender.11–16

Rowe and Killey, in their textbook,17,18 suggested a divi-sion ofmandibular fracture sites into twomain categories: (1)alveolar fractures not involving the basal bone and (2)fractures involving the basal bone. The great majority offractures were attributed to the second category. Singleunilateral basal bone fractures were further subdivided intosix regions (symphysis, canine, angle and body combined,ramus, coronoid, condyle). Fracture combinations within anyof these regions were distinguished into double unilateral,bilateral, and multiple fractures. Curiously enough the bor-derlines of the topographic regions were neither noted inwriting nor schematically specified. Instead of exactly indi-cating the involved area, representative fracture lines passingthrough each of the suggested regions were demonstratedusing plastic models, clinical photographs, or a variety of X-rays.

Huelke et al,19,20 in their studies on 319 case histories ofmandibular fractures from Ann Arbor, Michigan, reportedon 4 major locations: (1) chin fractures, between themental foramina or the corners of the mouth, (2) angle–body, fractures located between the gonial angle and themental foramen, (3) subcondylar, at the neck of the mandi-ble, and (4) “other” fractures, comprising the ramus, alveo-lar bone alone, and the coronoid process. The angle–bodyregion in this approach is of extensive width and offers azone for plenty of fracture assignments. In contrast, thelarge and undifferentiated category “other fracture” wasused, because there were no fractures in the ramus orcoronoid occurring in the study sample. Despite the some-what coarse and subjective categorization, the introductionof anatomic landmarks independent of the presence ofteeth was a novelty. Apart from the mental foramen, aline anterior to the ramus downwards to the mandibularbase was applied to delineate the regions in edentuloussubjects.

Dingman and Natvig8 have classified seven regions forfracture allocation (symphysis, body, alveolar process, an-gle, ramus, condyle process, coronoid process) with acartographic mapping of the sites displayed on a hemi-mandible in their early textbook article. The roots of the

lower canines and the borderlines of the angle region arethe essential markers to delineate these regions. The angleregion or the surgical angle conforms to a triangular areabounded by the anterior margin of themasseter muscle andby a line from the retromolar trigone to the “posterior-superior attachment of the masseter to the ramus.” Thebody region of the mandible spans between the canine andthe anterior boundary of the angle accordingly. The so-called “symphysis” refers to the intercanine area of themandible as adopted in this AO level 2 mandible fractureclassification system. The ramus region is bounded by thesuperior demarcation of the angle to two lines forming anapex at the sigmoid notch.8

The Dingman and Natvig classification and also the Roweand Killey classification are still the most popularly usedschemes around the world today.21 A major difference be-tween them is in the size of the angle region being notablywider in the Rowe and Killey classification due to a combina-tion with the body region. With the aim to determine the“weak” regions of the mandible with regard to the state ofdentition, Halazonetis22 used elements of both these classi-fications as well as Huelke landmarks20 to match identicalregions in dentulous and edentulous jaws.

Spiessl and Schroll10 added the glenoid fossa which is partof the temporal bone to a first classification layout whichessentially was adopted from Rowe and Killey,17 as well asDingman and Natvig.8

Kelly and Harrigan23 adhered to the prototypical mandib-ular divisions of former classifications; however, they devisedan arbitrary scheme of vertical or oblique fracture linecourses and simply defined their interdental origin for theirallocation.

Krüger23 devised a fracture classification and terminologythat entered into the AO CMFManual later years24,25with thefracture sites borrowed from Dingman and Natvig8 again.Based on the preparatorywork of Grätz26 the acronym FLOSAwas introduced by Spiessl9 to feed the numerous features ofmandibular fractures into a single concise formula (F ¼ frac-ture category; L ¼ localization/fracture site; O ¼ occlusion,S ¼ soft tissue involvement; A¼ associated fractures). A newsite-specific terminology (►Table 1) was created to label theanatomic regions, which essentially reproduced the Dingman

Table 1 (Continued)




Catapano et al35 Journal articleStatisticalevaluation

63 panfacial traumapatients retrospectiveanalysis using surro-gate parameters tovalidate the severityscore

Topographical fracture location inthe entire mandible: parasymphy-seal (¼ intercanine area), body,angle (¼ strip with the width of thethird molar), vertical ramus(¼ retromolar area behind thirdmolar to sigmoid notch), condylarhead and neck (extraarticular),condylar head and neck(intra-articular), glenoid fossa(intra-articular)

Facial Fracture Severity Score(FFSS) based on 41 facialregions and 3 grades of severity(displacement, number offractures, comminution,bone loss)



Dow

nloa

ded

by: T

hiem

e V

erla

gsgr

uppe

. Cop

yrig

hted

mat

eria

l.

and Natvig scheme as previously mentioned.10 The allocationof a fracture line to a region was determined by its course inthe basal zone of the mandible, irrespective of the dentoal-veolar or interdental pathway.

In a computer-based coding system of craniofacial frac-tures, Cooter and David27 defined each hemimandible as oneof 10 major unilateral anatomical zones and divided itostensibly into 7 subzones (►Table 1). Accounting for embry-ological, developmental, biomechanical, etiopathogenic, andepidemiological background knowledge, Gola et al28 remod-eled existing classifications with the claim to preclude termi-nological imprecision and to better comply the borderlinesbetween the regions with the variation in anatomic andclinical reality of mandibular fractures. They designedstraight “interregional” lines with angulation both in thefrontal and the sagittal plane. The lines pass through dentalcrowns (canine and third molar), bony landmarks (mentalforamen, preangular, and sigmoid notch), or the margins ofthe masseter muscle. In the sagittal plane, the three linesthrough the canine andmental foramen (¼ symphysis–ramusboundary), from the retromolar fossa to the preangular notchor the anteroinferior masseter insertion, respectively (¼“interbody–ramus” border), and from the sigmoid notch tothe posteroinferior masseter insertion (¼ “interangle–con-dyle” demarcation) are arranged in parallel. Thus, in theedentulous mandible the interregional separation lines canbe elegantly installed in a posterior–anterior fashion withthese parallels just touching bony landmarks. Likewise, in thislevel 2 proposal the angle is regarded as single centralconstituent of the anatomical ramus with its upper bordersshifted toward the condylar and coronoid base, resulting in apentagonal shape. A separate surgical ramus region is notdemarcated. In the first approach to establish a mandibularfracture severity score, Joos et al29 attributed a value rangingfrom 0 to 3 points depending on the anatomic location (fordetails, see ►Table 1) into the summation of the total scorewith a possible maximum of 15 points. The angle/ramus wasgrouped as a single anatomic constituent with three points asthe highest location score.

A reappraisal of Spiessl FLOSA classification equippedwithsurplus features (T ¼ teeth, D ¼ dislocation, I ¼ infection)was proposed by Pankratov and Robustova30 but ended upin information overload and inapplicability for routinepurposes.

In a study on the comparative performance of helical CTversus panorex tomography, Roth et al4 relied on an anatom-ical diagram of themandibular regions to identify the fracturelocation. The borders of the topographical division intoregions were not described.

With the aim to set up an improved “Mandible InjurySeverity Score” (MISS), Shetty et al31 made use of most of theindividual FLOSA components.9 Instead of recording associ-ated fractures (A), they includedmeasures for infection (I) andinterfragmentary displacement (D) modifying the previousacronym into FLOSID. The relative impact on the clinicaloutcome of each individual component was multiplied by acorresponding weighting factor and the resulting points wereadded to a summary score rating the injury severity. Apart

from a graphical scheme displaying the anatomic regionssimilarly to Spiessl proposal, the borderlines were not ver-bally specified. The interregional demarcations of this schemeare self-explaining if they extend from interdental spaces butthey appear at random in the anatomical ramus due to thelack of definite landmarks. A valuable remark is made, onwhere to assign fractures which extend across two adjoininganatomic regions. Referring to Spiessl “determining zone,”such fractures are suggested to be allocated to the basalregion that is predominantly involved.

Follmar et al32 get back to established facial fractureclassifications to offer an organized uniform reporting systemwhich seeks to avoid redundancies and improve communi-cation. A color-marking superimposed on the photograph of amacerated mandibula is used to specify the topographicalregions; their borderlines were defined with regard to inter-dental spaces (►Table 1).

A classification scheme in accordance with the AO/ASIF“Tripartite”— principle used in long bones and pelvis (seeAudigé et al1 in this Supplement)—was reported by Buitrago-Téllez et al.33 It was exclusively based on imaging analysis anddivided the mandible into two vertical compartments (ana-tomical ramus right/left), two lateral horizontal compart-ments (mandibular body and dentoalveolar process right/left), and one central compartment (symphysis and twoparasymphyseal regions). A region-specific 3 � 3 � 3 gridof categories (e.g., displacement type, multifragmentation,single fracture vs. fracture combinations) and specifications(e.g., fracture pattern—basal triangle, separate fracture lines,atrophy of the alveolar process, condylar head dislocation outof the fossa) was then imposed onto each of the threecompartments and transferred into a single fracture formula.While this ambitious proposal consisting of 75 items and thepossible permutations thereof was rather complex andmemo-technically demanding, the separation lines betweenthe compartments were kept easy and skimped. The bound-ary between the central and the horizontal compartmentswas placed on a vertical line through the apices of the canineroots. A vertical line in the interdental space between thesecond and third molar was suggested for the division of thehorizontal from the vertical compartments. Formal instruc-tions on how to split the compartments into their subunitswere not mentioned.

Carinci et al34 cameupwith a Facial Fracture Severity Score(FFSS) “scoring” method to stage mandibular fractures.Besides the anatomic sites (►Table 1), they essentiallyaccounted for the type (incomplete/complete) and numberof fracture lines in the alveolar process and/or the basal arch(single/double/triple) to indicate the severity stage.

Catapano et al35 styled an “FFSS” for the comprehensivedocumentation of panfacial fractures applying 41 anatomicalregions on the face and quantifying the severity in terms of adisruption grade within each of these regions. The extent ofthe regions in the mandible basically resembles FLOSA loca-tions9 andMISS taxonomy31 but the size ratio of the angle andthe ramus regionwas altered in favor of the latter (►Table 1).The angle region was confined to an area inferior to the thirdmolar, whereas the anteroinferior border of the ramus lies



Dow

nloa

ded

by: T

hiem

e V

erla

gsgr

uppe

. Cop

yrig

hted

mat

eria

l.

just posterior to the lower wisdom tooth. The superiorboundary of the ramus region corresponds to a horizontalline passing through the lowest point of themandibular notchas a tangent. In their specific classification of mandibularcondylar process fractures, Loukota et al37 already had re-ferred to the same line as reference to distinguish betweenfracture of the condylar neck and the condylar base (see Neffet al6 in this issue).

Besides the typical elements, this brief chronology of theexisting mandibular fracture classification systems showsinconsistencies and shortcomings of the evolving conceptsto this day. The topography of the anatomic regions hasusually been referred to the hemimandible, whereas morerecent classification attempts look at the entire mandible as asingle block28,31,35 (►Table 1). This level 2 proposal alsoregards the entire mandible, viewed in panorama style, toimprove comprehensiveness, to preclude mix-up of the rightand left mandibular halves, and to allow for a symphysisregion.

Two of four topographical regions of the mandible, respec-tively, continuously attracted particular attention: one, theturning points of the U-shaped mandibular arch from thelateral limbs into the anterior partition in the axial plane and,second, the corners between the lateral horizontal limbs andthe vertical posterior extensions in the sagittal plane, knownas the angle region or the surgical angle of the mandible.Further increased by the long canine roots and the lowerwisdom teeth, both regions are weak spots22,38,39 or “break-points” biomechanically, where the majority of fracturesusually occur. However, the determination of the accordingregions and borderlines has been a constant source of dis-crepancies. The lower canines, the mental foramen, or even acombination of both28 were used to delineate the symphysisto make up an intercanine or interforaminal unit (►Table 1).In anatomical/embryological terms, the symphysis refers tothe midline only; however, in this proposal it should be

understood that it includes the left and right parasymphysealarea. A true symphysis fracture might be conceived as avertical linear fracture in themidsagittal plane of the anteriormandible reminding to infantile development status of themandible, when it consisted of a pair of bones with a medianfibrous union. Yet, no difference is made in the level 2between median, paramedian, or any alternative fracturecourse within the symphysis, because only the region accom-modating a single or a multiple fractures is denominated as awhole. In level 2, the symphysis region corresponds to theintercanine area in between the two anterior transitionalzones.

The body region spreads from the anterior to the poste-rior transitional zone, which is the connection to the angle/ramus region. The extent and shaping of the angle regionwere subject to substantial variations (see ►Table 1

and ►Fig. 7). In the initial classification attempts, the angleconformed to a triangular-shaped area and was spacedapart from the ramus region; later, it was merged withthe body or with the ramus region to a singular unit. In thepast, the borders of these regions were hardly ever definedprecisely in writing or text form. Instead, it was relied onillustrative schemes and a sign language. So it is notsurprising that even key papers on the osteosynthesis inthe mandibular angle go without sparing a word to definethe involved region.39–45

In this level 2 classification attempt, the angle and theramus region are incorporated into a sole large unit, compa-rable to Gola et al.28 The anterior (and inferior) boundary ofthis angle/ramus region runs almost vertically from the distalaspect of the third molar to the inferior margin of themandible. The gable-shaped top end of the region coincideswith the base of the condylar process and the base of thecoronoid process, with both borderlines defined throughanatomical landmarks (mandibular notch, masseteric tuber-osity notch, subcoronoid indentation).

Figure 7 Variations in the extent of angle and ramus regions. (A) Region of the angle8,11,23; (B) body/angle region19,20; (C) location L4 (angular)31 angle34;(D) angle/ramus region28; (E) location L5 [R5] and L6 [R6]31 or angle and vertical ramus35; (F) posterior transition zone and angle/ramus region (AOmandible fracture classification level 2).



Dow

nloa

ded

by: T

hiem

e V

erla

gsgr

uppe

. Cop

yrig

hted

mat

eria

l.

The transitional zones introduced in this level 2 proposalrepresent cross-border areas between the adjoining regions ofthe mandibular arch. They are located in the two vulnerablezones of the mandibular arch already described. A transitionalzone has the function of a corridor, adding to the spatial extentof adjacent regions following clear rules to allocate fractures(►Fig. 2).

While a fracture course confined within a transition zoneis allocated to the adjoining posterior region, fractures cross-ing a transitional zone are allocated to both juxtaposedregions. Spiessl’s basal “determining zone” along the basalborder9 can be regarded as a precursor of the “transitionalzone” concept in this level 2 system. In contrast to Spiessl’shorizontally oriented ribbon-like zone, the transitional zonesare vertical strips in the width of the lower canine and thethird molar. Retrospectively, it may be assumed that Spiesslintended to avoid a reference to the teeth, since the state ofdentition and the degree of alveolar atrophy can vary. Inter-estingly, most of the existing classifications make use of thedentition to determine the anatomic distribution of fractureline courses. However none of the classifications had a designto record the actual tooth condition at all or in particulardetail, just as this level 2.

Concluding Note

The proposed system is simple enough for daily routine;however, it allows description of manifold fractures. Theoccurrence of single, double, triple, or multiple fractures iswell portrayed in the coding. A pure topographical classifica-tion system ultimately will not be suitable to portray thediversity and the overall complexities of a mandibular trau-ma. Nevertheless, the allocation of a fracture to an anatomicregion or site is deemed the initial step prior to more refinedways of analysis and orderly documentation as offered in thesubsequent level 3 article.2

AcknowledgmentsThis CMF classification project was funded by the AOFoundation and its AOCMF Specialty. Illustrations wereprepared byAO Education (publishing) by Jecca Reichmuthand her colleagues. The authors are grateful to all surgeons(as listed Audigé et al1 in this issue in alphabetic order)who participated in the successive classification sessionsand provided their fruitful support in the developmentand validation of this mandibular fracture classificationsystem.

References1 Audigé L, Cornelius CP, Di Ieva A, Prein J, CMF Classification Group.

The first comprehensive AO classification system for fractures ofthe craniomaxillofaxial skeleton: rationale, methodological back-ground, developmental process and objectives. CraniomaxillofacTrauma Reconstr 2014;7(Suppl 1):S6–S14

2 Cornelius CP, Audigé L, Kunz C, et al. The comprehensive AOCMFclassification system: mandible fractures - level 3 tutorial. Cra-niomaxillofac Trauma Reconstr 2014;7(Suppl 1):S31–S43

3 Buitrago-Téllez CH, Cornelius CP, Prein J, et al. The comprehensiveAOCMF classification system: radiological issues and systematicapproach. Craniomaxillofac Trauma Reconstr 2014;7(Suppl 1):S123–S130

4 Roth FS, Kokoska MS, Awwad EE, et al. The identification ofmandible fractures by helical computed tomography and panorextomography. J Craniofac Surg 2005;16(3):394–399

5 Anatomica T. International Anatomical Terminology. 1st ed. NewYork, NY: Thieme Medical Publishers; 1998

6 Neff A, Cornelius CP, Rasse M, et al. The comprehensive AOCMFclassification system: condylar process fractures - level 3 tutorial.Craniomaxillofac Trauma Reconstr 2014;7(Suppl 1):S44–S58

7 Marsh JL, Slongo TF, Agel J, et al. Fracture and dislocation classifi-cation compendium - 2007: Orthopaedic Trauma Associationclassification, database and outcomes committee. J Orthop Trauma2007;21(10, Suppl):S1–S133

8 Dingman RO, Natvig P. Surgery of Facial Fractuers. Philadelphia,PA: WB Saunders; 1964

9 Spiessl B. AO classification of mandibular fractures. In: Spiessl B,ed. Internal Fixation of the Mandible-A Manual of AO/ASIF Prin-ciples. 2nd ed. Berlin, Heidelberg, NewYork, London, Paris, Tokyo:Springer Verlag; 1989

10 Spiessl B, Schroll K. Unterkieferfrakturen, Vorbemerkungen. In:Nigst H, ed. Spezielle Frakturen-und Luxationslehre. 1st ed.Stuttgart New York: Thieme Verlag; 1972:102–107

11 Kelly DE, Harrigan WF. A survey of facial fractures: BellevueHospital, 1948-1974. J Oral Surg 1975;33(2):146–149

12 Bormann KH, Wild S, Gellrich NC, et al. Five-year retrospectivestudy of mandibular fractures in Freiburg, Germany: incidence,etiology, treatment, and complications. J Oral Maxillofac Surg2009;67(6):1251–1255

13 Meaders RA, Sullivan SM. The development and use of a comput-erized database for the evaluation of facial fractures incorporatingaspects of the AAOMS Parameters of Care. J Oral Maxillofac Surg1998;56(8):924–929

14 Olson RA, Fonseca RJ, Zeitler DL, Osbon DB. Fractures of themandible: a review of 580 cases. J Oral Maxillofac Surg 1982;40(1):23–28

15 Ellis E III,Moos KF, el-Attar A. Tenyears ofmandibular fractures: ananalysis of 2,137 cases. Oral Surg OralMedOral Pathol 1985;59(2):120–129

16 Chrcanovic BR, AbreuMH, Freire-Maia B, Souza LN. 1,454 mandib-ular fractures: a 3-year study in a hospital in BeloHorizonte, Brazil.J Craniomaxillofac Surg 2012;40(2):116–123

17 Rowe NL, Killey HC. Fractures of the facial skeleton. Baltimore:Williams & Wilkins; 1968

18 Rowe NL, Killey HC. General considerations and classification ofmandibular fractures. Baltimore: Williams & Wilkins; 1955

19 Huelke DF, Burdi AR, Eyman CE. Association between mandibularfractures and site of trauma, dentition and age. J Oral Surg AnesthHosp Dent Serv 1962;20:478–481

20 Huelke DF, Burdi AR, Eymen C. Mandibular fractures as related tosite of trauma and state of dentition. J Dent Res 1961;40(6):1262–1266

21 Luyk NH, Ferguson JW. The diagnosis and initial management ofthe fractured mandible. Am J Emerg Med 1991;9(4):352–359

22 Halazonetis JA. The ‘weak’ regions of the mandible. Br J Oral Surg1968;6(1):37–48

23 Krüger E. Mandibular fractures, 1. Classification, diagnosis andfundamentals of treatment. In: Krüger E, Schilli W. eds. Oral andMaxillofacial Traumatology. Chicago: Quintessence PublishingCompany; 1982:211–223

24 Prein J. Manual of Internal Fixation in the Cranio-Facial Skeleton.New York, NY: Springer; 1998

25 Schilli W, Stoll P, BährW, Prein J. Mandibular fractures. In: Prein J,ed. Manual of Internal Fixation in the Cranio-Facial Skeleton. NewYork, NY: Springer; 1998:86–87



Dow

nloa

ded

by: T

hiem

e V

erla

gsgr

uppe

. Cop

yrig

hted

mat

eria

l.

26 Grätz K. Eine neue Klassifikation zur Einteilung von Unterkiefer-frakturen Universität Basel; 1986

27 Cooter RD, David DJ. Computer-based coding of fractures in thecraniofacial region. Br J Plast Surg 1989;42(1):17–26

28 Gola R, Cheynet F, Carreau JP, Amrouche M. Proposal of a newtopographic classification of mandibular fractures [in French]. RevStomatol Chir Maxillofac 1996;97(2):59–71

29 Joos U, Meyer U, Tkotz T, Weingart D. Use of a mandibular fracturescore to predict the development of complications. J Oral Max-illofac Surg 1999;57(1):2–5, discussion 5–7

30 Pankratov AS, Robustova TG. A classification of mandibular frac-tions [in Russian]. Stomatologia (Mosk) 2001;80(2):29–32

31 Shetty V, Atchison K, Der-Matirosian C, et al. The mandible injuryseverity score: development and validity. J Oral Maxillofac Surg2007;65(4):663–670

32 Follmar KE, Baccarani A, Das RR, et al. A clinically applicablereporting system for the diagnosis of facial fractures. Int J OralMaxillofac Surg 2007;36(7):593–600

33 Buitrago-Téllez CH, Audigé L, Strong B, et al. A comprehensiveclassification of mandibular fractures: a preliminary agreementvalidation study. Int J OralMaxillofac Surg 2008;37(12):1080–1088

34 Carinci F, Arduin L, Pagliaro F, et al. Scoringmandibular fractures: atool for staging diagnosis, planning treatment, and predictingprognosis. J Trauma 2009;66(1):215–219

35 Catapano J, Fialkov JA, Binhammer PA, et al. A new system forseverity scoring of facial fractures: development and validation. JCraniofac Surg 2010;21(4):1098–1103

36 Loukota RA, Eckelt U, De Bont L, Rasse M. Subclassification offractures of the condylar process of the mandible. Br J OralMaxillofac Surg 2005;43(1):72–73

37 Ichim I, Swain MV, Kieser JA. Mandibular stiffness in humans:numerical predictions. J Biomech 2006;39(10):1903–1913

38 Craig M, Bir C, Viano D, Tashman S. Biomechanical response of thehuman mandible to impacts of the chin. J Biomech 2008;41(14):2972–2980

39 Bell RB, Wilson DM. Is the use of arch bars or interdental wirefixation necessary for successful outcomes in the open reductionand internal fixation of mandibular angle fractures? J Oral Max-illofac Surg 2008;66(10):2116–2122

40 Ellis E III. Management of fractures through the angle of themandible. OralMaxillofac Surg Clin North Am 2009;21(2):163–174

41 Fox AJ, Kellman RM. Mandibular angle fractures: two-miniplatefixation andcomplications. Arch Facial Plast Surg2003;5(6):464–469

42 Gear AJ, Apasova E, Schmitz JP, Schubert W. Treatment modalitiesfor mandibular angle fractures. J Oral Maxillofac Surg 2005;63(5):655–663

43 Haug RH, Serafin BL. Mandibular angle fractures: a clinical andbiomechanical comparison-the works of Ellis and Haug. Cranio-maxillofac Trauma Reconstr 2008;1(1):31–38

44 Haug RH, Peterson GP, Goltz M. A biomechanical evaluation ofmandibular condyle fracture plating techniques. J Oral MaxillofacSurg 2002;60(1):73–80, discussion 80–81

45 Schierle HP, Schmelzeisen R, Rahn B, Pytlik C. One- or two-platefixation of mandibular angle fractures? J Craniomaxillofac Surg1997;25(3):162–168

46 Rowe NL, Williams JL. Maxillofacial Injuries. Vol. 1. Edinburgh:Churchill Livingstone; 1985

47 David DJ. Facial fracture classification: current thoughts andapplications. J Craniomaxillofac Trauma 1999;5(4):31–36, discus-sion 37–38



Dow

nloa

ded

by: T

hiem

e V

erla

gsgr

uppe

. Cop

yrig

hted

mat

eria

l.

Appendix 1 Additional level 2 coding examples of mandibular fractures. (A) Level 2 code: 91 S. Fracture in the symphysis/parasymphysissubdivision. (B) Level 2 code: 91 m.B. Isolated body fracture. (C) Level 2 code: 91 m.B-A. Unilateral double mandibular fracture: Anterior body andangle/ramus region. (D) Level 2 code: 91 A.m. Isolated/single fracture in the mandibular angle/ramus region (vertical). (E) Level 2 code: 91 A.m.Isolated/single fracture in the mandibular angle/ramus region (horizontal). (F) Level 2 code: 91 A.m. Isolated/single fracture in the mandibularangle/ramus region (vertical in transition zone). (G) Level 2 code: 91 P.m. Isolated/single condylar base fracture on the right side with extensioninto the coronoid. There is however no coronoid fracture. (H) Level 2 code: 91 B-S. Fracture with contiguous involvement of two subdivisions; thebody on the right and the symphysis subdivision. The right angle is not included, since the fracture is centered in the body with a single lineterminating within the posterior transition zone. (I) Level 2 code: 91 C.S-B. Coronoid fracture on the right side combined with a contiguousfracture in the symphysis subdivision and body region on the left side (i.e. a non-cofined fracture). (J) Level 2 code: 91 P.S.P. Triple mandiblefracture: symphysis and condylar process bilaterally. (K) Level 2 code: 91 A.m.B. Bilateral double mandible fracture: Anterior body andcontralateral angle/ramus. (L) Level 2 code: 91 S. Bilateral double mandible fracture at the outer ends of the symphysis subdivision.



Dow

nloa

ded

by: T

hiem

e V

erla

gsgr

uppe

. Cop

yrig

hted

mat

eria

l.

Appendix 1 (Continued)



Dow

nloa

ded

by: T

hiem

e V

erla

gsgr

uppe

. Cop

yrig

hted

mat

eria

l.

the comprehensive aocmf classiﬁcation system: mandible ... · head & neck surgery, geisinger...

Documents