Treatment of chronic mandibular dislocations using miniplates: follow-up of 8 cases and literature review

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J Oral Maxillofac Surg67:2599-2604, 2009

Treatment of Chronic MandibularDislocations: A Comparison Between

Eminectomy and MiniplatesBelmiro Cavalcanti do Egito Vasconcelos, DDS, PhD,* and

Gabriela Granja Porto, DDS, MSc†

Purpose: Temporomandibular joint dislocation is defined as an excessive forward movement of thecondyle beyond the articular eminence with complete separation of the articular surfaces and fixation inthat position. The purpose of this study was to compare 2 types of treatment for chronic mandibulardislocations, eminectomy and miniplates, evaluate the results of these surgeries, and make a criticalreview of the literature.

Patients and Methods: The sample was obtained from the records of Oswaldo Cruz Hospital(Recife, Brazil) and comprised cases submitted to chronic mandibular dislocation treatment byeminectomy and by use of miniplates between 2000 and 2006. Preoperative and postoperativeassessment included a thorough history and physical examination to determine the maximal mouthopening, presence of pain and sounds, frequency of dislocations, recurrence rate, and presence offacial nerve paralysis.

Results: After eminectomy, the mean maximal mouth opening was 48.4 � 8.5 mm preoperatively and41.3 � 5.0 mm postoperatively. After the use of miniplates, it was 42.75 � 11.53 and 45.62 � 8.52 mm,respectively. There was no facial nerve paralysis after either treatment. Recurrence occurred withminiplates (11.11%) but not with eminectomy.

Conclusion: Eminectomy had less chance of recurrence without creating articular damage, and withminiplates, the chance of recurrence increased because there is always the possibility of the miniplatefracturing.© 2009 American Association of Oral and Maxillofacial Surgeons

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emporomandibular joint (TMJ) dislocation is defined asn excessive forward movement of the condyle beyondhe articular eminence with complete separation of therticular surfaces and fixation in that position.1,2 It isommonly associated with poor development of therticular fossa, laxity of the temporomandibular liga-

eceived from the University of Pernambuco, Recife, Brazil.

*Senior Lecturer, Department of Oral and Maxillofacial Surgery,

nd Director, Master’s and PhD Programs in Oral and Maxillofacial

urgery.

†Postgraduate Student, PhD Program in Oral and Maxillofacial

urgery.

Address correspondence and reprint requests to Dr Vasconcelos:

aculdade de Odontologia de Pernambuco, Departamento de Cirurgia

Traumatologia BMF, Av General Newton Cavalcanti, 1650 Cama-

agibe PE, Brazil; e-mail: [email protected]

2009 American Association of Oral and Maxillofacial Surgeons

278-2391/09/6712-0008$36.00/0

oi:10.1016/j.joms.2009.04.113

2599

ent or joint capsule, and excessive activity of theateral pterygoid and infrahyoid muscles due to drugse or disease.1,2

A variety of therapeutic approaches designed toimit the forward excursion of the condylar head haveeen applied, such as intracapsular injection of scle-osing solutions,3 intramuscular injection of botuli-um toxin type A,4 lateral pterygoid myotomy,5 scar-

fication of the temporalis tendon,6 and bone graftingugmentation or application of a well-designed allo-lastic impediment with vitallium mesh or titaniumlates.3,7 Another type of treatment is reduction ofhe eminence, thereby permitting free movement ofhe condyle.7 Each form of treatment has its owndvantages and disadvantages.

The aim of this study is to compare 2 techniques usedor the treatment of chronic mandibular dislocation:minectomy and miniplates. A descriptive statisticalnalysis is also presented, as well as a critical review ofhe literature stating and discussing the advantages and

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2600 CHRONIC MANDIBULAR DISLOCATION

atients and Methods

A retrospective evaluation of 10 patients treated byminectomy and 8 treated by use of miniplates withhronic mandibular dislocations was conducted at theivision of Oral and Maxillofacial Surgery, Oswaldoruz Hospital–University of Pernambuco, Recife, Bra-il, between 2000 and 2006.

The following criteria were used for inclusion inhe study: at least 5 episodes of dislocation peronth; inability to perform jaw movements to smile,

peak, or eat; and failure of conservative treatmentethods, such as orientation to self-limit jaw move-ents and the use of a chin cup.Radiographic examination included panoramic ra-

iographs and conventional tomography to determinehe height of the articular eminence. Preoperativessessment included a thorough history and physicalxamination to determine the maximal mouth open-ng (MMO) and frequency of dislocations; in addition,he patient’s age and gender were recorded. Theatients were preoperatively and postoperatively ex-mined and classified according to the grading systemf House and Brackmann8 to detect any signs of facialerve paralysis or paresthesia. The period of recoveryrom any paralysis was also observed.

Magnetic resonance imaging was used to determinehether 3 patients treated by eminectomy, with the

ongest follow-up, had articular damage.

SURGICAL PROCEDURES FOR EMINECTOMY

Exposure of the TMJ was done by the preauricularpproach described by Ellis and Zide9 with the pa-ient under general anesthesia. After exposure anddentification of the articular eminence, it was re-

oved with a No. 703 drill. The jaw movements werehen checked for interference and any required ad-ustments made (Fig 1).

IGURE 1. Surgical procedure for eminectomy. A, Identification ofrill.

asconcelos and Porto. Chronic Mandibular Dislocation. J Oral Maxillofac

SURGICAL PROCEDURES FOR MINIPLATES

The same exposure of the TMJ was done for thelacement of miniplates. After exposure and identifi-ation of the articular eminence, an L-shaped 2.0-mminiplate was used, where the short arm of the plateas fixed with two 6-mm screws and the long arm

erved as a mechanical obstacle in the condylar pathlaced inferior and anterior to the articular eminence.he jaw movements were then checked for interfer-nce and any required adjustments made (Fig 2).

esults

EMINECTOMY

The data of the patients treated by eminectomy,ncluding age, gender, MMO, presence of preopera-ive and postoperative pain and sounds, length ofollow-up, and frequency of dislocations are shown inable 1.The mean age of the patients in this group was 31.4

ears (range, 22-52 years). The mean duration of post-perative follow-up was 37.4 months (range, 2-63onths). There were a total of 20 eminectomies for

he treatment of chronic mandibular dislocation in 10atients.The mean preoperative and postoperative MMOas 48.4 � 8.5 mm and 41.3 � 5.0 mm, respectively.There were sounds in the TMJ in 4 patients preop-

ratively, and 2 continued to have this sign afterurgery. In 1 patient with no preoperative sounds,repitation was observed postoperatively.Of the 4 patients who reported pain preoperatively,

nly 1 continued to have this symptom. One patientho did not report pain preoperatively felt some pain

n the postoperative period.The magnetic resonance images in 3 patients

reated by eminectomy showed that there was norticular damage in any of them (Fig 3).

ar eminence. B, C, Removal of articular eminence with a No. 703

Surg 2009.

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VASCONCELOS AND PORTO 2601

No nerve paralysis or recurrence of mandibularislocation was observed in any patient.

MINIPLATES

The data of the patients treated by use ofiniplates, including age, gender, preoperative and

IGURE 2. Surgical procedure for miniplates. A, Placement of anide. C, Panoramic radiograph showing placement of miniplate in

asconcelos and Porto. Chronic Mandibular Dislocation. J Oral

Table 1. DATA OF PATIENTS TREATED BY EMINECTOMY

Patient No. Gender Age (yr)

MMO (mm)

Preop Postop

1 M 24 53 462 F 24 52 473 M 40 47 454 M 27 55 455 F 24 51 446 F 22 50 417 F 52 61 328 F 29 30 369 F 27 43 40

10 F 45 42 37

Abbreviations: Preop, preoperatively; Post, postoperative

asconcelos and Porto. Chronic Mandibular Dislocation. J Oral Maxillo

ostoperative MMO, follow-up and facial nerve injury,re shown in Table 2.

The mean age of the patients in this group was 29.3ears (range, 22-42 years). The mean duration of post-perative follow-up was 59.75 months (range, 48-69onths). There were a total of 16 placements of

d 2.0-mm miniplate on right side. B, Placement of miniplate on leftnd anterior to articular eminence.

fac Surg 2009.

ain SoundFollow-Up

(mo)

DislocationFrequency

(mo)Postop Preop Postop

N N N 63 2N N N 62 40N N Y 62 3N Y N 61 3Y N N 53 28N Y Y 38 14N Y N 17 21N N N 5 21N N N 10 7Y Y Y 3 1

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2602 CHRONIC MANDIBULAR DISLOCATION

iniplates for the treatment of chronic mandibularislocation in 8 patients.The mean preoperative and postoperative MMOas 42.75 � 11.53 mm and 45.62 � 8.52 mm, re-

pectively.The major complication found was unilateraliniplate fracture in 2 patients (Fig 2). In one of theseatients there was recurrence of the mandibular dis-

ocation. Both patients were treated by removal of theilateral miniplates and bilateral eminectomy, and atresent, they have shown no recurrence. No nervearalysis was observed in any patient.Comparisons of both treatments are shown in Ta-

les 3 and 4.

iscussion

Surgery is often appropriate when dislocation isrolonged or recurrent.10 Numerous surgical proce-ures for habitual dislocation have been described inhe literature based on the creation of a mechanicalbstacle in the condylar path, such as positioning theisc anterior to the condyle, downfracturing of theygomatic arch and fixation medial to the eminence,r insertion of implants into the eminence.10,11 In

FIGURE 3. Magnetic resonance images showing plac

asconcelos and Porto. Chronic Mandibular Dislocation. J Oral

Table 2. DATA OF PATIENTS TREATED WITH MINIPLATE

Patient No. Gender Age (yr)

MMO (mm)

Preop Postop

1 M 30 39 352 F 42 24 453 F 22 57 414 M 40 40 375 F 26 40 526 F 24 34 50

7 F 32 57 618 F 24 51 44

Abbreviations: Preop, preoperatively; Post, postoperative

asconcelos and Porto. Chronic Mandibular Dislocation. J Oral Maxillo

ddition, there are other modes of treatment that aimo restrict movement of the condyle such as the in-ection of sclerosing substances or even the inductionf fibrosis in the tissues adjacent to the joint.11,12

nother type of treatment is removal of the mechan-cal obstacles in the condylar path; one such proce-ure is eminectomy, which was introduced byyrhaug in 19511,10 and has been used with satisfac-

ory results and efficacy according to the litera-ure.13-15

Each form of treatment has its own advantages andisadvantages. The placement of a titanium miniplate

n the articular eminence aims to prevent hyperexcur-ion of the condyle, thereby avoiding its displace-ent. It has the advantage of being a reversible and

ess invasive method, but it has the disadvantage ofeading to a decrease in MMO,11,12 which was seen innly 4 patients (50%) of our series (Table 2). Thether 2 who had an increase in mouth opening hadlso the plate fracture. The possibility of plate fractur-ng is another disadvantage, requiring a further oper-tion for removal of the device and choice of a newreatment, which occurred in 2 cases in our series.ccording to the results of this study, we suggest thatlate fracturing could be explained by material fa-

of articular disc on left side (A) and on right side (B).

fac Surg 2009.

ComplicationsFollow-Up

(mo)Facial Nerve

Paralysis

e 67 Ne 67 Ne 48 Ne 69 Ne 67 Nrrence and plate fractureright side

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VASCONCELOS AND PORTO 2603

igue, where the plate was bent during the adaptationo the articular eminence during surgery. Thereforehe plate is not proper for the treatment of condylarislocation, which is in agreement with the findingsf Kuttenberger and Hardt.11

The way of placing the miniplate may influence thenal result. As described by Buckley and Terry,16 inur study the short arm of the miniplate was fixed inhe zygomatic arch, and the long arm served as aechanical barrier to condyle movement. With the

im of increasing the articular eminence, Puelachernd Waldhart12 and Bakardjiev3 used the miniplateontouring it, thus creating a mechanical obstacle inhe condylar path. Bakardjiev3 stated that placing bi-ortical screws in the zygomatic arch may decreasehe chance of loosening of the miniplate. In this studyhe miniplates were placed according to the tech-iques used in these studies: the short arm of thelate was fixed with two 6-mm screws, and the longrm served as a mechanical obstacle in the condylarath placed inferior and anterior to the articular em-

nence.The placement of an obstacle in the articular emi-

ence may result in some degree of limitation ofouth opening. Removing the eminence (ie, eminec-

omy) may lead to hypermobility, which may cause aegeneration of the joint and excessive mouth open-

ng10; however, according to our study, this was notound to be true. All the joints in 3 patients treated byminectomy appeared normal on magnetic resonancemages. This being so, it was to be expected that the

ean preoperative MMO would be lower than theostoperative MMO. Nevertheless, the opposite wasbserved in this study, which might be accounted fory the presence of fibrosis, resulting from the surgicalrocedure itself.Eminectomy, even when performed with rotary

nstruments, may leave rugged areas that could lead torepitation of the bone during the movement ofouth opening. This is the likely explanation for theresence of crepitation in the TMJ only postopera-ively in patient 3. The major complaint of patients ishe condyle locking anterior to the eminence itself,

Table 3. PREOPERATIVE AND POSTOPERATIVEMAXIMAL INTERINCISAL OPENING IN EMINECTOMYAND MINIPLATE GROUPS

Treatment

Mean Maximal Interincisal Opening(mm)

Preoperatively Postoperatively

minectomy 48.4 � 8.5 41.3 � 5.0iniplate 42.75 � 11.53 45.62 � 8.52

asconcelos and Porto. Chronic Mandibular Dislocation. J Oralaxillofac Surg 2009.

ecause it leads to a stretching of articular compo-ents, causing pain. As a result, there is a completeemission of the symptoms after treatment. No causalelationship was found for the pain reported by pa-ient 5, and the pain that failed to subside in patient0 was likely because of this patient’s short postop-rative follow-up.Regardless of the surgical approach used to gain

ccess to the TMJ, the final dissection places the facialerve at risk for damage.17,18 A loss of function of therontalis and orbicularis oculi muscles is always aossibility.17 The prevalence of complications, suchs injury to the facial nerve, is very low,19,20 with ratesarying from 9% to 18%21 and 1.5% to 32%,18 and anyesulting lesion usually disappears within 6 months.hus the correct choice of technique for making thepproach to the TMJ in this study was seen to haveeen made, because no facial nerve paralysis wasbserved in any of the cases. The chosen technique9

llows protection to the nerve since a subperiostealissection along the lateral face of the zygomatic arch

s made, leaving the temporal branches of the facialerve located within the substance of the retractedap.Eminectomy had less chance of recurrence without

reating articular damage, and by use of miniplates,he chance of recurrence increased because there islways the possibility of the miniplate fracturing, re-uiring a further operation for removal of the devicend choice of a new treatment. Thus eminectomy washown to be more efficient in the treatment ofhronic mandibular dislocations than the use ofiniplates in relation to postoperative MMO, recur-

ence, and articular function.

eferences1. Cardoso AB, Vasconcelos BCE, Oliveira DM: Comparative study

of eminectomy and use of bone miniplate in the articulareminence for the treatment of recurrent temporomandibularjoint dislocation. Braz J Otorhinolaryngol 71:32, 2005

2. Hale RH: Treatment of recurrent dislocation of the mandible:

Table 4. RECURRENCE IN EMINECTOMY ANDMINIPLATE GROUPS

Total [n (%)]

WithRecurrence

[n (%)]

WithoutRecurrence

[n (%)]

reatmentEminectomy 10 (55.56) 0 (0) 10 (55.55)Miniplate 8 (44.44) 2 (11.11) 6 (33.33)

otal 18 (100) 2 (11.11) 16 (88.89)

asconcelos and Porto. Chronic Mandibular Dislocation. J Oralaxillofac Surg 2009.

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2604 CHRONIC MANDIBULAR DISLOCATION

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5. Laskin DM: Myotomy for management of recurrent and pro-tracted mandibular dislocation. Trans Int Conf Oral Surg 4:264,1973

6. Gould JF: Shortening of the temporalis tendon for hypermo-bility of the temporomandibular joint. J Oral Surg 36:781,1978

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