Monocortical Miniplate Fixation of Mandibular Angle Fractures Frederic E.
Levy, MD; Robert W. Smith, MD; Rick
\s=b\ Noncompression monocortical miniplate fixation of mandibular fractures has become a reliable method of providing rigid fixation and eliminating the need for intermaxillary fixation. Recent studies, using a variety of internal fixation techniques, have described high complication rates at the mandibular angle. This article compares the use of one miniplate vs two miniplates in treatment of angle fractures. Since September 1985, 61 patients with 63 mandibular angle fractures have been treated with miniplates. Forty-four fractures were fixed with two miniplates. Six complications (3.1%) occurred, five of which were in the one-miniplate group. The complication rate in the double\x=req-\ miniplate group is the lowest reported of any plating technique. The use of two miniplates has proved to be an effective method of treating mandibular angle frac-
tures.
(Arch Otolaryngol Head Neck Surg. 1991;117:149-154)
Accepted for publication September 4, 1990. From the Department of Otolaryngology, University of Minnesota Medical Center, Minneapolis (Drs Levy, Smith, and Marentette), and the Division of Otolaryngology\p=n-\Headand Neck Surgery, Loma Linda (Calif) University Medical Center (Dr Odland). Presented at the annual spring meeting of the American Academy of Facial Plastic and Reconstructive Surgery, Palm Beach, Fla, May 5,1990. Reprint requests to Department of Otolaryngology, Box 396, University of Minnesota Medical Center, Minneapolis, MN 55455 (Dr Levy).
M.
Odland, MD; Lawrence J. Marentette, MD
Traditional
open methods of man¬ dible fracture fixation included wire osteosynthesis and intermaxil¬ lary fixation (IMF).1 Plating tech¬ niques, the current state of the art, achieves rigid fixation and obviates the need for IMF. Both compression and
noncompression plating systems are currently in use. Proponents of compression plating systems claim that rigid fixation can¬ not be attained without bicortical screw
The frequent involvement of the mandibular angle in jaw fractures (up to 28.5%) can be attributed to its thin cross-sectional bone area and the pres¬ ence of the third molar tooth socket.8 Several recent studies have docu¬ mented high complication rates for internal fixation of the mandibular angle.9 '2 At the University of Minne¬ sota-affiliated hospitals, a twominiplate technique has been devel¬ oped for angle fracture stabilization.
engagement.24 Nevertheless,
Michelet et al5 and Champy et al6 have documented low complication rates with noncompression monocortical miniplate fixation. Through an in¬ traoral approach, miniplates can be applied to fractures at all points of the mandible. Fractures between the men¬ tal foramina are approached with a standard genioplasty incision. Angle fractures are accessed via a sagittal split osteotomy incision. The advan¬ tages of miniplates include: (1) avoid¬ ing an external incision, (2) eliminat¬ ing potential for inferior alveolar and marginal mandibular nerve damage, and (3) simultaneous surveillance of fracture line reduction and occlusal relationships. For these reasons, miniplate osteosynthesis has become the plating method of choice at our in¬ stitution. Overall complication rates for compression and noncompression fixation of mandible fractures have been the same.3-7
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MATERIALS AND METHODS Materials Mandibular angle fractures treated at the University of Minnesota-affiliated hos¬ pitals between September 1985 and October 1989 were reviewed retrospectively. Only those fractures repaired with monocortical miniplate fixation technique were included in the study. Infected or comminuted frac¬ tures were not treated with miniplates. The number and sites of fractures were recorded, as well as the presence or absence of IMF, duration of IMF, number of miniplates used, and whether or not teeth were extracted. Complications were tabu¬ lated; these were defined as infection, malocclusion, delayed union or nonunion, dehiscence, osteomyelitis, and nerve injury
secondary to surgical manipulation. The following treatment categories were established: (1) one miniplate/no IMF, (2) one miniplate/IMF, (3) two miniplates/no IMF, and (4) two miniplates/IMF. Postoperative follow-up examinations were typically performed at 1,2,4,6, and 12
Table 1.—Associated Fractures Observed in 61 Patients With Mandibular Angle Fractures Site
Ipsilateral
Contralateral
2
3
0
4
Subcondylar Angle Body
2
3
Parasymphyseal
3
19
Ramus
0
1
weeks, with additional examinations if nec¬ essary. Postreduction panoramic radio¬ graphs were taken in most cases. Surgical Technique The surgical procedure is undertaken as soon as possible after the injury. General anesthesia is administered with nasotracheal intubation. Intravenous antibiotics, usually penicillin G or cefazolin, are given preoperatively. The teeth are brushed, and the mouth is irrigated with chlorhexidine rinse. Dental extraction with meticulous mucosal closure is carried out on nonviable teeth in the fracture line. Premorbid occlu¬ sion is reestablished via bimanual manipu¬ lation. This is secured through either clas¬ sic arch bar fixation, Ivy loops, or Gilmer
Fig 1.—Location of miniplates used in treatment of mandibular angle fractures, superimposed Champy's ideal line of osteosynthesis.
Table 2.—Results of Treatment of Mandibular Angle Fractures, Through October 1989'
ligatures. An incision identical to that for sagittal split osteotomy is made over the external oblique line, beginning from the first molar tooth to halfway up the ascending ramus on
the buccal side. If the third molar tooth was extracted, the incision incorporates the split mucosa of the tooth socket. The peri¬ osteum is then elevated off the mandible exposing the fracture site. Bone holding forceps are applied, if necessary, to realign and stabilize the fragments. Through the intraoral incision, a four-,
five-, or six-hole, noncompression monocor¬ tical miniplate (Champy, Martin Co, Tüb¬ ingen, Federal Republic of Germany, or Würzburg, Oswald-Leibinger Co, Tübingen, Federal Republic of Germany) is carefully contoured to the superior buccal cortical of the mandible across the fracture line (Fig 1). The miniplate must contact the bone surface throughout its length. The screw holes are created, drilling through a trocar inserted through the skin adj acent to the fracture. A low-speed drill is employed, and copious irrigation is used to prevent thermal bone injury. The drill holes are secured with self-tapping monocortical screws applied through the trocar. The second miniplate (a four-, five-, or six-hole plate) is then contoured to the mandibular surface along the external oblique line (Fig 1). Through the intraoral incision, the miniplate is held along the mandibular surface. The screw holes are area
September
on
1985
No. of Fractures Mandibular
Group One miniplate/no IMF
Associated
Angle 10; 6 left and 4 right
Complications Infection—drained, in¬
miniplate/IMF (average IMF, 23 days)
6
open-bite
mal-
occlusion—orthodontla Infection—drained, in¬ travenous antibiotics
9; 3 left and
right
22
travenous antibiotics
Anterior
One
Complication Rate, %
30
Infection—drained, in¬ travenous antibiotics screw,
Nonunion—lag
external fixation
re¬
quired Total Two
miniplates/no IMF
18; 4
Two
miniplates/IMF (average IMF, 23.5 days)
0.0
14 left and
right
14; 11 left and 3 right
Infection / abscess— drained, packed, In¬ travenous antibiotics
3.1
Total 12
patients
7.1
with
inadequate follow-up.
IMF indicates
created transorally with the low-speed drill. At least two screws are used on each side of the fracture line. Again, liberal irri¬ gation is employed. Once IMF is released, the fracture line is checked for mobility, and occlusion is ex¬ amined to see that premorbid relationships have been restored. Copious irrigation is performed to clear bony and/or metallic particles. A 0.25-in Penrose drain is placed through the intraoral incision. Mucosa is
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intermaxillary fixation.
reapproximated using 3-0 and 4-0 polyglactin 920 suture (Vicryl). When IMF is un¬ necessary for associated fracture stabiliza¬ tion, arch bars or wires are removed from the teeth. The external stab incision is closed with 5-0 chromic suture. A postreduction panoramic radiograph (Panorex) is taken, and the patient is administered intravenous antibiotics. Discharge from the hospital usually occurs on the first day postoperatively.
Fig 2.—Panoramic radiograph (preoperative) dibular angle fracture.
of
patient
with left man¬
Fig 3.—Panoramic radiograph (3 months postoperatively) depicting healed angle fracture with miniplates in position. The oblique line plate spans the third molar tooth socket. This case nicely depicts the stability provided by two miniplates when a third molar tooth involved in the frac¬ ture line is extracted.
RESULTS
Sixty-one patients with 63 mandib¬ ular angle fractures were reviewed in this study. There were 52 men and nine women ranging in age from 18 to 47 years
(mean
age, 28.6
years). Thirty-
patients had one associated man¬ dible fracture, and three patients had two associated fractures. The most common location of associated mandi¬ ble fractures was the contralateral
one
parasymphyseal area (51%) (Table 1). Forty-five patients (71.4% ) had a leftsided angle fracture and 18 patients (28.6%) had a right-sided fracture. Two patients sustained bilateral angle
fractures. Nine of 19 patients with adequate follow-up in the one-miniplate group had associated mandible fractures. Contralateral fractures included four
parasymphyseal, two body, one ramus, and one subcondylar fracture. One pa¬ tient sustained an ipsilateral ramus
Twenty-two associated frac¬ tures were noted in the patients in the two-miniplate group with adequate follow-up. Contralateral fractures in¬ cluded 11 parasymphyseal, four angle, two body, and two subcondylar frac¬ tures. Two patients had ipsilateral subcondylar fractures, and one patient had an ipsilateral body fracture (Table fracture.
1).
patients were dentulous. Twelve patients had teeth extracted, all of All
which were either No. 17,18, 30, or No. 32. The average follow-up time was 19 weeks; 39 patients (75% ) were followed up for at least 3 months. The majority
(seven) of the 12 patients with 6 to 12 weeks of follow-up had later clinic vis¬ its other than in the otolaryngology department. Complaints referrable to their jaw fracture were registered in none of the clinic visit notes. A mini¬ mum follow-up time of 6 weeks was accepted, thus excluding 12 patients from the statistically analyzed group. Only two patients had their miniplates removed. Two overall categories were estab¬ lished. The first category, representing early experience with miniplates, de¬ scribes patients receiving one miniplate. The second category describes
patients receiving These
were
two
miniplates.
further divided into the
following groups: (1) one miniplate/no IMF, (2) one miniplate/IMF, (3) two miniplates/no IMF, and (4) two miniplates/IMF. Associated mandibular fractures were treated with miniplate fixation, except for subcondylar frac¬ tures that necessitated IMF only. Ini¬ tially, patients treated with two miniplates were alternately assigned IMF or no IMF. Thus, five patients were en¬ tered into the two-miniplate/IMF
group who did not have associated fractures. No difference in therapeutic outcome was noted. All subsequent patients with isolated angle fractures
received miniplates only. The average duration of IMF was 23 days in the one-miniplate category and 23.5 days in the two-miniplate category. Complications were defined as infec¬ tion, malocclusion, delayed union or
nonunion, dehiscence, osteomyelitis, and nerve injury secondary to surgical
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manipulation. In the one-miniplate category, five of 19 patients experienced complications (Table 2). These included three infec¬ tions, one delayed union, and one an¬ terior open-bite malocclusion. All of
the infections were noted within the first week postoperatively. Two of the three patients who developed infec¬ tions were in the one-miniplate/IMF group. Treatment in all three cases of infection consisted of intraoral inci¬ sion and drainage and intravenous an¬ tibiotics. Two of three patients in the one-miniplate category who had a tooth extracted developed an infection. These patients without further was noted in one
proceeded
to union
problems. Nonunion patient at 3.5 months
postoperatively, on removal of his miniplate. This patient removed his IMF within the first postoperative week. A lag screw was placed, and bi¬ phase external fixation was main¬
tained for 2 months. He eventually achieved union. The patient who de¬ veloped an anterior open-bite malocclusion responded well to orthodontic
manipulation. Only one of 32 patients receiving two miniplates experienced a complication (Table 2). One of eight patients in the two-miniplate category who had a tooth extracted developed an infection. This patient was in the two-miniplate/ IMF group. An infection occurred, which was successfully managed with incision and drainage and intravenous antibiotics. Uneventful healing en¬ sued. There
were no
instances of
delayed
Table
3.—Comparison
of Results of Recent Studies
on
Mandibular Angle Fixation*
Technique Two miniplates One minlplate One angled DCP One miniplate Lag screw
Source /Year/Location Present study, 1990, Minneapolis, Minn Strelzow and Strelzow, " 1983, St Louis, Mo Wald et al,15 1988, Los Angeles, Calif Niederdellmann and Shetty,! 1987, Federal Republic of Germany_
One One
Cawood,'0 1985, England Theriot et al," 1987, San Antonio, Tex Mommaerts and Engelke,12 1985,
One
IMF
miniplate straight DCP miniplate
Complications No. (%) 1/32 (3.1) 5/19 (26.3) 1/14 (7.1) 3/36 (8.3) 8/50 (16.0) 5/27 4/21 4/15
(18.5) (19.0) (26.6)
Switzerland
*DCP Indicates dynamic compression plate; IMF, intermaxillary fixation; plus sign, sign, IMF absent.
union, dehiscence, osteomyelitis, or in¬
due to
injury surgical manipulation in either group. evidence Statistical ( 2 6.16, < .025) indicates that the higher number of complications observed in the one-miniplate group was not merely due to chance (Figs 2 and 3).
ferior alveolar
nerve
=
COMMENT The mandibular angle is that por¬ tion of the jaw which is interposed be¬ tween the thicker tooth-bearing man¬ dibular body and the thinner ascend¬ ing ramus.13 The masseter muscle covers this area laterally, inserting at the body-angle interface, as well as at the angle itself. In the angle region, the
cross-sectional bone
area
decreases
as
the alveolar ridge becomes more me¬ dial. The third molar tooth is located precisely at this point of angulation between the posterior body and the ramus.' Unerupted or impacted wis¬ dom teeth create an area of weakness, thus, the fracture line often encom¬ passes the third molar tooth socket. These two anatomic factors account for the frequent involvement of the angle in jaw fractures.914 A fracture of the angle is termed fa¬ vorable or unfavorable, depending on the direction of the fracture line in the horizontal and vertical plane and the consequent potential for displacement. Most mandibular angle fractures ex¬ tend from the surgical angle down¬ ward and backward.9 An upward, for¬ ward, and medial displacement of the ramus occurs due to the pull of the el¬ evator group of muscles, ie, the mas¬ seter, medial and lateral pterygoids, and the temporalis muscles. The ante-
IMF present; and minus
rior fragment is displaced downward and inward by the depressor group, ie, the geniohyoid, genioglossus, mylohyoid, and digastric muscles. The result¬ ing forces are tensile at the upper bor¬ der and compressive at the lower bor¬ der of the mandibular angle. The traditional open method of mandible fracture treatment consists of wire osteosynthesis of bone frag¬ ments and 4- to 8-week IMF.13 Poten¬ tial problems of IMF are well known and include compromised oral airway, inadequate nutritional intake with weight loss, social inconvenience, tem¬ poromandibular joint articular carti¬ lage thinning or ankylosis, and patient noncompliance with frequent removal of arch bars.111416 Metal plate stabili¬ zation, either by compression or noncompression technique, is now consid¬ ered the state of the art. Plating achieves rigid fixation and obviates the need for IMF. Proponents of compres¬ sion systems suggest that rigid fixa¬ tion cannot be achieved without bicor¬ tical engagement of screws.24 None¬ theless, Michelet et al5 and Champy et al6 have obtained superb results with monocortical fixation techniques.5-6 Experiments conducted by Champy and associates6 in Strasbourg, France, enabled modification of a monocortical miniplate fixation technique intro¬ duced by Michelet in 1973.s Champy and coworkers6 acknowledged that healing had been achieved for decades with noncompressive methods (eg, IMF). Their biomechanical studies re¬ sulted in the concept of an ideal line of osteosynthesis and led to consistent success in mandible fracture treat¬ ment. Taking into account torsional,
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tensile, and compressive forces at all points of the mandible, the ideal lines of osteosynthesis were described (Fig 1). This corresponded to a line of ten¬
sion at the base of the alveolar pro¬ While bending moments in¬ crease from the symphysis to the an¬ gle, torsional forces decrease.17 Miniplates were designed to be well tolerated, adaptable, and strong enough to counter forces up to 60 to 100 decanewtons (daN)/mm2. Their elastic limit of flexibility was 70 to 80 daN/ mm2, and the rupture point was 95 to 110 daN/mm2. One or two miniplates across a fracture of any mandibular area could guarantee stability. Ten¬ sion and compression lines of the man¬ dible have also been described by other investigators.18 Furthermore, Worthington and Champy19 considered the concept of "stress shielding." They stated, "physiologic stresses can stim¬ ulate osteogenic cells, either by a pi¬ ezoelectric effect or a mechanochemical effect. Conversely, lack of physio¬ logic stimulation may lead to bone loss. A too rigid plate may exert what is known as a 'stress shielding' effect. With a very rigid plate, lines of tension and compression may be seen experi¬ mentally to pass through the plate rather than through the bone, thus, a 'stress shielding' effect is noted on the bone."19 A small, thin miniplate with monocortical screws can be fixed subapically as a tension band (Fig 1). The angle region, according to Worthington and Champy, is best fixed along the oblique line, as high as possible. In the anterior region, between the mental foramina, two miniplates are necessary: one is fixed at the inferior border, and the second is fixed 5 mm above the first, at least 5 mm below the level of the alve¬ olar processes. Intraoral miniplate ap¬ plication eliminates visible external scars, diminishes the potential for in¬ ferior alveolar and marginal mandib¬ ular nerve damage, and allows simul¬ taneous observation of fracture line reduction and occlusal relationships. Major complications occurring with mandible fracture fixation include in¬ fection, malocclusion, delayed union or nonunion, osteomyelitis, and inferior alveolar or marginal mandibular nerve injury due to surgical manipu-
cesses.
lation.8'9·20 Infection is the most fre¬ quent problem and may lead to the
more serious consequences of non¬ union and osteomyelitis. We were able to find six reports an¬ alyzing results of mandibular angle fracture fixation. Complication rates varied with technique (Table 3). Strel¬ zow and Strelzow14 achieved a 7.1% complication rate through the use of
externally applied angled compres¬ sion plate. No IMF was employed. One
an
infection occurred where an involved third molar tooth was not extracted at the time of surgery. Uneventful heal¬ ing occurred after tooth extraction and antibiotic administration. Wald et al15 used one minifragment compression plate without IMF to treat angle frac¬ tures. Three of 36 patients developed infections, all of which were treated with drainage and antibiotics. Union occurred in all three patients. This in¬ traoral method resulted in an 8.3% rate of infection.15 Niederdellmann and Shetty9 summarized their results of lag screw fixation of noncomplicated angle fractures. Their intraoral method featured a 16.0% complication rate and required reoperation for screw removal at six months. Two in¬ fections occurred, including a perimandibular abscess and a case of os¬ teomyelitis at the fracture line. Three persistent sensory deficits were noted, presumably of the inferior alveolar nerve. Malocclusion or malposition of the fragments was seen in three more patients. The authors stated that 96% of patients showed "uneventful" heal¬ ing. Cawood10 placed one noncompres¬ sion miniplate, without IMF, through a buccal incision to achieve an 18.5% major complication rate at the angle. Complications included three wound dehiscences, one infection, and one malocclusion. Final outcomes were not available. Theriot et al" employed one
straight dynamic compression plate, placed intraorally for angle fracture stabilization. Due to a complication rate of 19%, this group switched to using two miniplates (Synthes), one of
which is fixed with bicortical screws, and 3- to 6-week IMF.11-21 Four of 21 patients developed infections. Third molar teeth were removed in all of these patients. Following removal of the compression plates, healing was
uneventful.
Finally, Mommaerts and Engelke12 applied one noncompression miniplate to the external oblique line.
The authors described the results of miniplate fixation of 42 mandible frac¬ tures at all locations. Four of 15 pa¬ tients with angle fractures developed complications; however, delineation of the specific problems in these individ¬ uals was not available. Their 26.6% complication rate at the angle proved similar to our experience with one
plate.12
Recently, biomechanical studies of Kroon22 have shown that axial loading in the molar region produced inferior splaying in a model of a single miniplated angle fracture. This exper¬ imental situation correlates with chewing of food in the molar area. With one miniplate fixed along the oblique line, an axial load shifts the tension side to the caudal margin of the mandible. This in vitro observation may explain the relatively poor results obtained in our one-miniplate group. Two miniplates, fixed along the dual lines of osteosynthesis at the angle successfully overcome this effect. At the University of Minnesotaaffiliated hospitals, the Champy tech¬ nique was first used in September 1985. Initially, the classic principles of the
Champy technique were employed in treating angle fractures. One miniplate was secured along the oblique line, using a minimum of two screws on
either side of the fracture line. After using this technique in 19 patients, it became clear that it was yielding an
unacceptably high (26.3%) complica¬ tion rate. Regardless of the presence of IMF, five of 19 patients developed a complication. Notable was that two of the three patients in the one-miniplate category who had a tooth extracted developed an infection. When a frac¬ ture is treated with traditional meth¬
ods of IMF and wire osteosynthesis, tooth extraction can lead to destabilization.23 This could result in postop¬ erative infection. If rigid fixation tech¬ niques are properly applied, extraction should not result in destabilization.24 Extraction of grossly carious teeth in a fracture line can result in a higher in¬ cidence of infection, but the infection rate is even higher if these teeth are retained in the fracture line. The
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higher infection rate in the oneminiplate group reflects the fact that one patient had exposed necrotic pulp with periosteal pathology and that in this series one miniplate did not pro¬ vide adequate stability. Furthermore, noncompliance in the postoperative period is a factor in this predomi¬ nantly indigent population.
Champy et al17 described two lines of
osteosynthesis at the mandibular an¬ gle. In addition to the external oblique line, a second line is located at the level of the dento-alveolar junction and an¬
terior to the canal of the inferior alve¬ olar nerve. The senior author (L.J.M.) began using miniplates in these loca¬ tions on angle fractures that were not infected or comminuted. The subse¬ quent use of two miniplates in man¬ dibular angle fractures has resulted in a 3.1% complication rate, with one complication in 32 fractures that were operated on. Eight patients in the two-miniplate group had dental ex¬ traction at the fracture site. One pa¬ tient developed an infection. With drainage and antibiotics, this patient proceeded to union. The presence or absence of IMF had no effect on the outcome in patients treated with two miniplates. The distribution of associ¬ ated fractures was proportionally sim¬ ilar in both the one- and two-miniplate groups of patients. Statistical evidence ( 2 6.16, < .025) indicates that the higher number of complications ob¬ served in the patients treated with one miniplate was not merely due to chance. We conclude that two miniplates, rather than a single miniplate, are a more effective method of treating mandibular angle fractures in our pop¬ ulation. This study represents the first published report of the use of two miniplates in the angle region. The 3.1% complication rate for this method is lower than for the other se¬ ries reviewed. The miniplate technique for stabili¬ zation of mandible fractures produces results comparable to compression os¬ teosynthesis. Although some studies have shown high complication rates in mandibular angle fracture fixation, the use of two miniplates at the angle achieves acceptable results. =
We thank Molly Driscoll and CiderPress Pub¬ lishing, St Paul, Minn, for production assistance.
References 1. Rowe NL, Killey HC. Fractures of the Facial Skeleton. 2nd ed. Edinburgh, Scotland: E & S Livingstone; 1970. 2. Schilli W. Compression osteosynthesis. J Oral Surg. 1977;35:802-808. 3. Luhr HG. Compression plate osteosynthesis through the Luhr system. In: Kruger E, Schilli W, eds. Oral and Maxillofacial Traumatology. Chicago, Ill: Quintessence; 1982:319-348. 4. Becker R. Stable compression plate fixation of mandibular fractures. Br J Oral Surg. 1974; 12:13-23. 5. Michelet FX, Deymes J, Dessus B. Osteosynthesis with miniaturized screwed plates in maxillofacial surgery. J Maxillofac Surg. 1973;1:79-84. 6. Champy M, Lodde JP, Schmitt R, et al. Mandibular osteosynthesis by miniaturized screwed plate via a buccal approach. J Maxillofac Surg.
1978;6:14-21.
7. Gerlach KL, Khouri M, Pape HD, Champy M. Die Ergebnisse der Miniplattenosteosynthese bei 1000 Unterkieferfrakturen in der K\l=o"\lnerund Strassburger Klinik. Dtsch Zahnarztl Z. 1983; 38:363-366. 8. Mathog RH, Boies LR, Nonunion of the mandible. Laryngoscope. 1976;86:908-920. 9. Niederdellmann H, Shetty V. Solitary lag screw osteosynthesis in the treatment of frac-
angle of the mandible: a retrospective study. Plast Reconstr Surg. 1987;80:68-74. 10. Cawood JI. Small plate osteosynthesis of mandibular fractures. Br J Oral Maxillofac Surg.
Strasbourg miniplate osteosynthesis. In: Kruger E, Schilli W, eds. Oral and Maxillofacial Traumatology. Chicago, Ill: Quintessence; 1986:
tures of the
JP. The
1985;23:77-91.
19-43. 18. Tillmann B, Harle F, Schleicher A. Biomechanik des Unterkiefers. Dtsch Zahnartztl Z.
11. Theriot BA, Van Sickels JE, Triplett RG, Nishioka GJ. Intraosseous wire fixation versus rigid osseous fixation of mandibular fractures. J Oral Maxillofac Surg. 1987;45:577-582. 12. Mommaerts MY, Engelke W. Erfahrungen mit der Osteosynthese-Platte nach Champy/ Lodde bei Unterkieferfrakturen. Dtsch Z Mund Kiefer Gesichts Chir. 1986;10:94-101. 13. Dingman RO, Natvig P. Surgery of Facial Fractures. Philadelphia, Pa: WB Saunders Co; 1964. 14. Strelzow VV, Strelzow AG. Osteosynthesis of mandibular fractures in the angle region. Arch
Otolaryngol. 1983;109:403-406. 15. Wald RM, Abemayor E, Zemplenyi J, et al.
The transoral treatment of mandibular fractures
using noncompression miniplates: a prospective study. Ann Plast Surg. 1988;20:409-413. 16. Glineburg RW, Laskin DM, Blaustein DI. The effects of immobilization on the primate temporomandibular joint. J Oral Maxillofac Surg. 1982;40:1, 3-8. 17.
Champy M, Pape HD, Gerlach KL, Lodde
1983;38:285-293. 19. Worthington P, Champy M. Monocortical miniplate osteosynthesis. Otolaryngol Clin North Am. 1987;20:607-620. 20. Giordano AM, Foster CA, Boies LR, Maisel RH. Chronic osteomyelitis following mandibular fractures and its treatment. Arch Otolaryngol. 1982;108:30-33. 21. Nishioka GJ, Van Sickels JE. Transoral plating of mandibular angle fractures: a technique. Oral Surg. 1988;5:531-535.
22. Kroon F. Effects of three dimensional loadon stability of internal fixation of mandible fractures. In: Spiessl B, ed. Internal Fixation of the Mandible. Berlin, Federal Republic of Germany: Springer-Verlag; 1989:26-27. 23. Schetty V, Freymiller E. Teeth in the line of fracture: a review. J Oral Maxillofac Surg. 1989; 47:1303-1306. 24. Spiessl B, ed. Internal Fixation of the Mandible. Berlin, Federal Republic of Germany: Springer-Verlag; 1989:230-236.
ing
In Other AMA Journals AJDC
Women in Medicine: Fantasies, Dreams, Myths, and Realities Catherine DeAngelis, MD (AJDC. 1991;145:49-52). Influence of Otitis Media on the Correlation Between Rectal and Auditory Canal Temperatures Thomas E. Terndrup, MD, Agnes Wong, MD (AJDC. 1991;145:75-78). Cat-Scratch Disease: Acute Encephalopathy and Other Neurologic Manifestations Hugh A. Carithers, MD, A. M. Margileth, MD (AJDC. 1991;145:98-101).
Downloaded From: http://archotol.jamanetwork.com/ by a Oakland University User on 05/31/2015
Levy, MD; Robert W. Smith, MD; Rick
\s=b\ Noncompression monocortical miniplate fixation of mandibular fractures has become a reliable method of providing rigid fixation and eliminating the need for intermaxillary fixation. Recent studies, using a variety of internal fixation techniques, have described high complication rates at the mandibular angle. This article compares the use of one miniplate vs two miniplates in treatment of angle fractures. Since September 1985, 61 patients with 63 mandibular angle fractures have been treated with miniplates. Forty-four fractures were fixed with two miniplates. Six complications (3.1%) occurred, five of which were in the one-miniplate group. The complication rate in the double\x=req-\ miniplate group is the lowest reported of any plating technique. The use of two miniplates has proved to be an effective method of treating mandibular angle frac-
tures.
(Arch Otolaryngol Head Neck Surg. 1991;117:149-154)
Accepted for publication September 4, 1990. From the Department of Otolaryngology, University of Minnesota Medical Center, Minneapolis (Drs Levy, Smith, and Marentette), and the Division of Otolaryngology\p=n-\Headand Neck Surgery, Loma Linda (Calif) University Medical Center (Dr Odland). Presented at the annual spring meeting of the American Academy of Facial Plastic and Reconstructive Surgery, Palm Beach, Fla, May 5,1990. Reprint requests to Department of Otolaryngology, Box 396, University of Minnesota Medical Center, Minneapolis, MN 55455 (Dr Levy).
M.
Odland, MD; Lawrence J. Marentette, MD
Traditional
open methods of man¬ dible fracture fixation included wire osteosynthesis and intermaxil¬ lary fixation (IMF).1 Plating tech¬ niques, the current state of the art, achieves rigid fixation and obviates the need for IMF. Both compression and
noncompression plating systems are currently in use. Proponents of compression plating systems claim that rigid fixation can¬ not be attained without bicortical screw
The frequent involvement of the mandibular angle in jaw fractures (up to 28.5%) can be attributed to its thin cross-sectional bone area and the pres¬ ence of the third molar tooth socket.8 Several recent studies have docu¬ mented high complication rates for internal fixation of the mandibular angle.9 '2 At the University of Minne¬ sota-affiliated hospitals, a twominiplate technique has been devel¬ oped for angle fracture stabilization.
engagement.24 Nevertheless,
Michelet et al5 and Champy et al6 have documented low complication rates with noncompression monocortical miniplate fixation. Through an in¬ traoral approach, miniplates can be applied to fractures at all points of the mandible. Fractures between the men¬ tal foramina are approached with a standard genioplasty incision. Angle fractures are accessed via a sagittal split osteotomy incision. The advan¬ tages of miniplates include: (1) avoid¬ ing an external incision, (2) eliminat¬ ing potential for inferior alveolar and marginal mandibular nerve damage, and (3) simultaneous surveillance of fracture line reduction and occlusal relationships. For these reasons, miniplate osteosynthesis has become the plating method of choice at our in¬ stitution. Overall complication rates for compression and noncompression fixation of mandible fractures have been the same.3-7
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MATERIALS AND METHODS Materials Mandibular angle fractures treated at the University of Minnesota-affiliated hos¬ pitals between September 1985 and October 1989 were reviewed retrospectively. Only those fractures repaired with monocortical miniplate fixation technique were included in the study. Infected or comminuted frac¬ tures were not treated with miniplates. The number and sites of fractures were recorded, as well as the presence or absence of IMF, duration of IMF, number of miniplates used, and whether or not teeth were extracted. Complications were tabu¬ lated; these were defined as infection, malocclusion, delayed union or nonunion, dehiscence, osteomyelitis, and nerve injury
secondary to surgical manipulation. The following treatment categories were established: (1) one miniplate/no IMF, (2) one miniplate/IMF, (3) two miniplates/no IMF, and (4) two miniplates/IMF. Postoperative follow-up examinations were typically performed at 1,2,4,6, and 12
Table 1.—Associated Fractures Observed in 61 Patients With Mandibular Angle Fractures Site
Ipsilateral
Contralateral
2
3
0
4
Subcondylar Angle Body
2
3
Parasymphyseal
3
19
Ramus
0
1
weeks, with additional examinations if nec¬ essary. Postreduction panoramic radio¬ graphs were taken in most cases. Surgical Technique The surgical procedure is undertaken as soon as possible after the injury. General anesthesia is administered with nasotracheal intubation. Intravenous antibiotics, usually penicillin G or cefazolin, are given preoperatively. The teeth are brushed, and the mouth is irrigated with chlorhexidine rinse. Dental extraction with meticulous mucosal closure is carried out on nonviable teeth in the fracture line. Premorbid occlu¬ sion is reestablished via bimanual manipu¬ lation. This is secured through either clas¬ sic arch bar fixation, Ivy loops, or Gilmer
Fig 1.—Location of miniplates used in treatment of mandibular angle fractures, superimposed Champy's ideal line of osteosynthesis.
Table 2.—Results of Treatment of Mandibular Angle Fractures, Through October 1989'
ligatures. An incision identical to that for sagittal split osteotomy is made over the external oblique line, beginning from the first molar tooth to halfway up the ascending ramus on
the buccal side. If the third molar tooth was extracted, the incision incorporates the split mucosa of the tooth socket. The peri¬ osteum is then elevated off the mandible exposing the fracture site. Bone holding forceps are applied, if necessary, to realign and stabilize the fragments. Through the intraoral incision, a four-,
five-, or six-hole, noncompression monocor¬ tical miniplate (Champy, Martin Co, Tüb¬ ingen, Federal Republic of Germany, or Würzburg, Oswald-Leibinger Co, Tübingen, Federal Republic of Germany) is carefully contoured to the superior buccal cortical of the mandible across the fracture line (Fig 1). The miniplate must contact the bone surface throughout its length. The screw holes are created, drilling through a trocar inserted through the skin adj acent to the fracture. A low-speed drill is employed, and copious irrigation is used to prevent thermal bone injury. The drill holes are secured with self-tapping monocortical screws applied through the trocar. The second miniplate (a four-, five-, or six-hole plate) is then contoured to the mandibular surface along the external oblique line (Fig 1). Through the intraoral incision, the miniplate is held along the mandibular surface. The screw holes are area
September
on
1985
No. of Fractures Mandibular
Group One miniplate/no IMF
Associated
Angle 10; 6 left and 4 right
Complications Infection—drained, in¬
miniplate/IMF (average IMF, 23 days)
6
open-bite
mal-
occlusion—orthodontla Infection—drained, in¬ travenous antibiotics
9; 3 left and
right
22
travenous antibiotics
Anterior
One
Complication Rate, %
30
Infection—drained, in¬ travenous antibiotics screw,
Nonunion—lag
external fixation
re¬
quired Total Two
miniplates/no IMF
18; 4
Two
miniplates/IMF (average IMF, 23.5 days)
0.0
14 left and
right
14; 11 left and 3 right
Infection / abscess— drained, packed, In¬ travenous antibiotics
3.1
Total 12
patients
7.1
with
inadequate follow-up.
IMF indicates
created transorally with the low-speed drill. At least two screws are used on each side of the fracture line. Again, liberal irri¬ gation is employed. Once IMF is released, the fracture line is checked for mobility, and occlusion is ex¬ amined to see that premorbid relationships have been restored. Copious irrigation is performed to clear bony and/or metallic particles. A 0.25-in Penrose drain is placed through the intraoral incision. Mucosa is
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intermaxillary fixation.
reapproximated using 3-0 and 4-0 polyglactin 920 suture (Vicryl). When IMF is un¬ necessary for associated fracture stabiliza¬ tion, arch bars or wires are removed from the teeth. The external stab incision is closed with 5-0 chromic suture. A postreduction panoramic radiograph (Panorex) is taken, and the patient is administered intravenous antibiotics. Discharge from the hospital usually occurs on the first day postoperatively.
Fig 2.—Panoramic radiograph (preoperative) dibular angle fracture.
of
patient
with left man¬
Fig 3.—Panoramic radiograph (3 months postoperatively) depicting healed angle fracture with miniplates in position. The oblique line plate spans the third molar tooth socket. This case nicely depicts the stability provided by two miniplates when a third molar tooth involved in the frac¬ ture line is extracted.
RESULTS
Sixty-one patients with 63 mandib¬ ular angle fractures were reviewed in this study. There were 52 men and nine women ranging in age from 18 to 47 years
(mean
age, 28.6
years). Thirty-
patients had one associated man¬ dible fracture, and three patients had two associated fractures. The most common location of associated mandi¬ ble fractures was the contralateral
one
parasymphyseal area (51%) (Table 1). Forty-five patients (71.4% ) had a leftsided angle fracture and 18 patients (28.6%) had a right-sided fracture. Two patients sustained bilateral angle
fractures. Nine of 19 patients with adequate follow-up in the one-miniplate group had associated mandible fractures. Contralateral fractures included four
parasymphyseal, two body, one ramus, and one subcondylar fracture. One pa¬ tient sustained an ipsilateral ramus
Twenty-two associated frac¬ tures were noted in the patients in the two-miniplate group with adequate follow-up. Contralateral fractures in¬ cluded 11 parasymphyseal, four angle, two body, and two subcondylar frac¬ tures. Two patients had ipsilateral subcondylar fractures, and one patient had an ipsilateral body fracture (Table fracture.
1).
patients were dentulous. Twelve patients had teeth extracted, all of All
which were either No. 17,18, 30, or No. 32. The average follow-up time was 19 weeks; 39 patients (75% ) were followed up for at least 3 months. The majority
(seven) of the 12 patients with 6 to 12 weeks of follow-up had later clinic vis¬ its other than in the otolaryngology department. Complaints referrable to their jaw fracture were registered in none of the clinic visit notes. A mini¬ mum follow-up time of 6 weeks was accepted, thus excluding 12 patients from the statistically analyzed group. Only two patients had their miniplates removed. Two overall categories were estab¬ lished. The first category, representing early experience with miniplates, de¬ scribes patients receiving one miniplate. The second category describes
patients receiving These
were
two
miniplates.
further divided into the
following groups: (1) one miniplate/no IMF, (2) one miniplate/IMF, (3) two miniplates/no IMF, and (4) two miniplates/IMF. Associated mandibular fractures were treated with miniplate fixation, except for subcondylar frac¬ tures that necessitated IMF only. Ini¬ tially, patients treated with two miniplates were alternately assigned IMF or no IMF. Thus, five patients were en¬ tered into the two-miniplate/IMF
group who did not have associated fractures. No difference in therapeutic outcome was noted. All subsequent patients with isolated angle fractures
received miniplates only. The average duration of IMF was 23 days in the one-miniplate category and 23.5 days in the two-miniplate category. Complications were defined as infec¬ tion, malocclusion, delayed union or
nonunion, dehiscence, osteomyelitis, and nerve injury secondary to surgical
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manipulation. In the one-miniplate category, five of 19 patients experienced complications (Table 2). These included three infec¬ tions, one delayed union, and one an¬ terior open-bite malocclusion. All of
the infections were noted within the first week postoperatively. Two of the three patients who developed infec¬ tions were in the one-miniplate/IMF group. Treatment in all three cases of infection consisted of intraoral inci¬ sion and drainage and intravenous an¬ tibiotics. Two of three patients in the one-miniplate category who had a tooth extracted developed an infection. These patients without further was noted in one
proceeded
to union
problems. Nonunion patient at 3.5 months
postoperatively, on removal of his miniplate. This patient removed his IMF within the first postoperative week. A lag screw was placed, and bi¬ phase external fixation was main¬
tained for 2 months. He eventually achieved union. The patient who de¬ veloped an anterior open-bite malocclusion responded well to orthodontic
manipulation. Only one of 32 patients receiving two miniplates experienced a complication (Table 2). One of eight patients in the two-miniplate category who had a tooth extracted developed an infection. This patient was in the two-miniplate/ IMF group. An infection occurred, which was successfully managed with incision and drainage and intravenous antibiotics. Uneventful healing en¬ sued. There
were no
instances of
delayed
Table
3.—Comparison
of Results of Recent Studies
on
Mandibular Angle Fixation*
Technique Two miniplates One minlplate One angled DCP One miniplate Lag screw
Source /Year/Location Present study, 1990, Minneapolis, Minn Strelzow and Strelzow, " 1983, St Louis, Mo Wald et al,15 1988, Los Angeles, Calif Niederdellmann and Shetty,! 1987, Federal Republic of Germany_
One One
Cawood,'0 1985, England Theriot et al," 1987, San Antonio, Tex Mommaerts and Engelke,12 1985,
One
IMF
miniplate straight DCP miniplate
Complications No. (%) 1/32 (3.1) 5/19 (26.3) 1/14 (7.1) 3/36 (8.3) 8/50 (16.0) 5/27 4/21 4/15
(18.5) (19.0) (26.6)
Switzerland
*DCP Indicates dynamic compression plate; IMF, intermaxillary fixation; plus sign, sign, IMF absent.
union, dehiscence, osteomyelitis, or in¬
due to
injury surgical manipulation in either group. evidence Statistical ( 2 6.16, < .025) indicates that the higher number of complications observed in the one-miniplate group was not merely due to chance (Figs 2 and 3).
ferior alveolar
nerve
=
COMMENT The mandibular angle is that por¬ tion of the jaw which is interposed be¬ tween the thicker tooth-bearing man¬ dibular body and the thinner ascend¬ ing ramus.13 The masseter muscle covers this area laterally, inserting at the body-angle interface, as well as at the angle itself. In the angle region, the
cross-sectional bone
area
decreases
as
the alveolar ridge becomes more me¬ dial. The third molar tooth is located precisely at this point of angulation between the posterior body and the ramus.' Unerupted or impacted wis¬ dom teeth create an area of weakness, thus, the fracture line often encom¬ passes the third molar tooth socket. These two anatomic factors account for the frequent involvement of the angle in jaw fractures.914 A fracture of the angle is termed fa¬ vorable or unfavorable, depending on the direction of the fracture line in the horizontal and vertical plane and the consequent potential for displacement. Most mandibular angle fractures ex¬ tend from the surgical angle down¬ ward and backward.9 An upward, for¬ ward, and medial displacement of the ramus occurs due to the pull of the el¬ evator group of muscles, ie, the mas¬ seter, medial and lateral pterygoids, and the temporalis muscles. The ante-
IMF present; and minus
rior fragment is displaced downward and inward by the depressor group, ie, the geniohyoid, genioglossus, mylohyoid, and digastric muscles. The result¬ ing forces are tensile at the upper bor¬ der and compressive at the lower bor¬ der of the mandibular angle. The traditional open method of mandible fracture treatment consists of wire osteosynthesis of bone frag¬ ments and 4- to 8-week IMF.13 Poten¬ tial problems of IMF are well known and include compromised oral airway, inadequate nutritional intake with weight loss, social inconvenience, tem¬ poromandibular joint articular carti¬ lage thinning or ankylosis, and patient noncompliance with frequent removal of arch bars.111416 Metal plate stabili¬ zation, either by compression or noncompression technique, is now consid¬ ered the state of the art. Plating achieves rigid fixation and obviates the need for IMF. Proponents of compres¬ sion systems suggest that rigid fixa¬ tion cannot be achieved without bicor¬ tical engagement of screws.24 None¬ theless, Michelet et al5 and Champy et al6 have obtained superb results with monocortical fixation techniques.5-6 Experiments conducted by Champy and associates6 in Strasbourg, France, enabled modification of a monocortical miniplate fixation technique intro¬ duced by Michelet in 1973.s Champy and coworkers6 acknowledged that healing had been achieved for decades with noncompressive methods (eg, IMF). Their biomechanical studies re¬ sulted in the concept of an ideal line of osteosynthesis and led to consistent success in mandible fracture treat¬ ment. Taking into account torsional,
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tensile, and compressive forces at all points of the mandible, the ideal lines of osteosynthesis were described (Fig 1). This corresponded to a line of ten¬
sion at the base of the alveolar pro¬ While bending moments in¬ crease from the symphysis to the an¬ gle, torsional forces decrease.17 Miniplates were designed to be well tolerated, adaptable, and strong enough to counter forces up to 60 to 100 decanewtons (daN)/mm2. Their elastic limit of flexibility was 70 to 80 daN/ mm2, and the rupture point was 95 to 110 daN/mm2. One or two miniplates across a fracture of any mandibular area could guarantee stability. Ten¬ sion and compression lines of the man¬ dible have also been described by other investigators.18 Furthermore, Worthington and Champy19 considered the concept of "stress shielding." They stated, "physiologic stresses can stim¬ ulate osteogenic cells, either by a pi¬ ezoelectric effect or a mechanochemical effect. Conversely, lack of physio¬ logic stimulation may lead to bone loss. A too rigid plate may exert what is known as a 'stress shielding' effect. With a very rigid plate, lines of tension and compression may be seen experi¬ mentally to pass through the plate rather than through the bone, thus, a 'stress shielding' effect is noted on the bone."19 A small, thin miniplate with monocortical screws can be fixed subapically as a tension band (Fig 1). The angle region, according to Worthington and Champy, is best fixed along the oblique line, as high as possible. In the anterior region, between the mental foramina, two miniplates are necessary: one is fixed at the inferior border, and the second is fixed 5 mm above the first, at least 5 mm below the level of the alve¬ olar processes. Intraoral miniplate ap¬ plication eliminates visible external scars, diminishes the potential for in¬ ferior alveolar and marginal mandib¬ ular nerve damage, and allows simul¬ taneous observation of fracture line reduction and occlusal relationships. Major complications occurring with mandible fracture fixation include in¬ fection, malocclusion, delayed union or nonunion, osteomyelitis, and inferior alveolar or marginal mandibular nerve injury due to surgical manipu-
cesses.
lation.8'9·20 Infection is the most fre¬ quent problem and may lead to the
more serious consequences of non¬ union and osteomyelitis. We were able to find six reports an¬ alyzing results of mandibular angle fracture fixation. Complication rates varied with technique (Table 3). Strel¬ zow and Strelzow14 achieved a 7.1% complication rate through the use of
externally applied angled compres¬ sion plate. No IMF was employed. One
an
infection occurred where an involved third molar tooth was not extracted at the time of surgery. Uneventful heal¬ ing occurred after tooth extraction and antibiotic administration. Wald et al15 used one minifragment compression plate without IMF to treat angle frac¬ tures. Three of 36 patients developed infections, all of which were treated with drainage and antibiotics. Union occurred in all three patients. This in¬ traoral method resulted in an 8.3% rate of infection.15 Niederdellmann and Shetty9 summarized their results of lag screw fixation of noncomplicated angle fractures. Their intraoral method featured a 16.0% complication rate and required reoperation for screw removal at six months. Two in¬ fections occurred, including a perimandibular abscess and a case of os¬ teomyelitis at the fracture line. Three persistent sensory deficits were noted, presumably of the inferior alveolar nerve. Malocclusion or malposition of the fragments was seen in three more patients. The authors stated that 96% of patients showed "uneventful" heal¬ ing. Cawood10 placed one noncompres¬ sion miniplate, without IMF, through a buccal incision to achieve an 18.5% major complication rate at the angle. Complications included three wound dehiscences, one infection, and one malocclusion. Final outcomes were not available. Theriot et al" employed one
straight dynamic compression plate, placed intraorally for angle fracture stabilization. Due to a complication rate of 19%, this group switched to using two miniplates (Synthes), one of
which is fixed with bicortical screws, and 3- to 6-week IMF.11-21 Four of 21 patients developed infections. Third molar teeth were removed in all of these patients. Following removal of the compression plates, healing was
uneventful.
Finally, Mommaerts and Engelke12 applied one noncompression miniplate to the external oblique line.
The authors described the results of miniplate fixation of 42 mandible frac¬ tures at all locations. Four of 15 pa¬ tients with angle fractures developed complications; however, delineation of the specific problems in these individ¬ uals was not available. Their 26.6% complication rate at the angle proved similar to our experience with one
plate.12
Recently, biomechanical studies of Kroon22 have shown that axial loading in the molar region produced inferior splaying in a model of a single miniplated angle fracture. This exper¬ imental situation correlates with chewing of food in the molar area. With one miniplate fixed along the oblique line, an axial load shifts the tension side to the caudal margin of the mandible. This in vitro observation may explain the relatively poor results obtained in our one-miniplate group. Two miniplates, fixed along the dual lines of osteosynthesis at the angle successfully overcome this effect. At the University of Minnesotaaffiliated hospitals, the Champy tech¬ nique was first used in September 1985. Initially, the classic principles of the
Champy technique were employed in treating angle fractures. One miniplate was secured along the oblique line, using a minimum of two screws on
either side of the fracture line. After using this technique in 19 patients, it became clear that it was yielding an
unacceptably high (26.3%) complica¬ tion rate. Regardless of the presence of IMF, five of 19 patients developed a complication. Notable was that two of the three patients in the one-miniplate category who had a tooth extracted developed an infection. When a frac¬ ture is treated with traditional meth¬
ods of IMF and wire osteosynthesis, tooth extraction can lead to destabilization.23 This could result in postop¬ erative infection. If rigid fixation tech¬ niques are properly applied, extraction should not result in destabilization.24 Extraction of grossly carious teeth in a fracture line can result in a higher in¬ cidence of infection, but the infection rate is even higher if these teeth are retained in the fracture line. The
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higher infection rate in the oneminiplate group reflects the fact that one patient had exposed necrotic pulp with periosteal pathology and that in this series one miniplate did not pro¬ vide adequate stability. Furthermore, noncompliance in the postoperative period is a factor in this predomi¬ nantly indigent population.
Champy et al17 described two lines of
osteosynthesis at the mandibular an¬ gle. In addition to the external oblique line, a second line is located at the level of the dento-alveolar junction and an¬
terior to the canal of the inferior alve¬ olar nerve. The senior author (L.J.M.) began using miniplates in these loca¬ tions on angle fractures that were not infected or comminuted. The subse¬ quent use of two miniplates in man¬ dibular angle fractures has resulted in a 3.1% complication rate, with one complication in 32 fractures that were operated on. Eight patients in the two-miniplate group had dental ex¬ traction at the fracture site. One pa¬ tient developed an infection. With drainage and antibiotics, this patient proceeded to union. The presence or absence of IMF had no effect on the outcome in patients treated with two miniplates. The distribution of associ¬ ated fractures was proportionally sim¬ ilar in both the one- and two-miniplate groups of patients. Statistical evidence ( 2 6.16, < .025) indicates that the higher number of complications ob¬ served in the patients treated with one miniplate was not merely due to chance. We conclude that two miniplates, rather than a single miniplate, are a more effective method of treating mandibular angle fractures in our pop¬ ulation. This study represents the first published report of the use of two miniplates in the angle region. The 3.1% complication rate for this method is lower than for the other se¬ ries reviewed. The miniplate technique for stabili¬ zation of mandible fractures produces results comparable to compression os¬ teosynthesis. Although some studies have shown high complication rates in mandibular angle fracture fixation, the use of two miniplates at the angle achieves acceptable results. =
We thank Molly Driscoll and CiderPress Pub¬ lishing, St Paul, Minn, for production assistance.
References 1. Rowe NL, Killey HC. Fractures of the Facial Skeleton. 2nd ed. Edinburgh, Scotland: E & S Livingstone; 1970. 2. Schilli W. Compression osteosynthesis. J Oral Surg. 1977;35:802-808. 3. Luhr HG. Compression plate osteosynthesis through the Luhr system. In: Kruger E, Schilli W, eds. Oral and Maxillofacial Traumatology. Chicago, Ill: Quintessence; 1982:319-348. 4. Becker R. Stable compression plate fixation of mandibular fractures. Br J Oral Surg. 1974; 12:13-23. 5. Michelet FX, Deymes J, Dessus B. Osteosynthesis with miniaturized screwed plates in maxillofacial surgery. J Maxillofac Surg. 1973;1:79-84. 6. Champy M, Lodde JP, Schmitt R, et al. Mandibular osteosynthesis by miniaturized screwed plate via a buccal approach. J Maxillofac Surg.
1978;6:14-21.
7. Gerlach KL, Khouri M, Pape HD, Champy M. Die Ergebnisse der Miniplattenosteosynthese bei 1000 Unterkieferfrakturen in der K\l=o"\lnerund Strassburger Klinik. Dtsch Zahnarztl Z. 1983; 38:363-366. 8. Mathog RH, Boies LR, Nonunion of the mandible. Laryngoscope. 1976;86:908-920. 9. Niederdellmann H, Shetty V. Solitary lag screw osteosynthesis in the treatment of frac-
angle of the mandible: a retrospective study. Plast Reconstr Surg. 1987;80:68-74. 10. Cawood JI. Small plate osteosynthesis of mandibular fractures. Br J Oral Maxillofac Surg.
Strasbourg miniplate osteosynthesis. In: Kruger E, Schilli W, eds. Oral and Maxillofacial Traumatology. Chicago, Ill: Quintessence; 1986:
tures of the
JP. The
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11. Theriot BA, Van Sickels JE, Triplett RG, Nishioka GJ. Intraosseous wire fixation versus rigid osseous fixation of mandibular fractures. J Oral Maxillofac Surg. 1987;45:577-582. 12. Mommaerts MY, Engelke W. Erfahrungen mit der Osteosynthese-Platte nach Champy/ Lodde bei Unterkieferfrakturen. Dtsch Z Mund Kiefer Gesichts Chir. 1986;10:94-101. 13. Dingman RO, Natvig P. Surgery of Facial Fractures. Philadelphia, Pa: WB Saunders Co; 1964. 14. Strelzow VV, Strelzow AG. Osteosynthesis of mandibular fractures in the angle region. Arch
Otolaryngol. 1983;109:403-406. 15. Wald RM, Abemayor E, Zemplenyi J, et al.
The transoral treatment of mandibular fractures
using noncompression miniplates: a prospective study. Ann Plast Surg. 1988;20:409-413. 16. Glineburg RW, Laskin DM, Blaustein DI. The effects of immobilization on the primate temporomandibular joint. J Oral Maxillofac Surg. 1982;40:1, 3-8. 17.
Champy M, Pape HD, Gerlach KL, Lodde
1983;38:285-293. 19. Worthington P, Champy M. Monocortical miniplate osteosynthesis. Otolaryngol Clin North Am. 1987;20:607-620. 20. Giordano AM, Foster CA, Boies LR, Maisel RH. Chronic osteomyelitis following mandibular fractures and its treatment. Arch Otolaryngol. 1982;108:30-33. 21. Nishioka GJ, Van Sickels JE. Transoral plating of mandibular angle fractures: a technique. Oral Surg. 1988;5:531-535.
22. Kroon F. Effects of three dimensional loadon stability of internal fixation of mandible fractures. In: Spiessl B, ed. Internal Fixation of the Mandible. Berlin, Federal Republic of Germany: Springer-Verlag; 1989:26-27. 23. Schetty V, Freymiller E. Teeth in the line of fracture: a review. J Oral Maxillofac Surg. 1989; 47:1303-1306. 24. Spiessl B, ed. Internal Fixation of the Mandible. Berlin, Federal Republic of Germany: Springer-Verlag; 1989:230-236.
ing
In Other AMA Journals AJDC
Women in Medicine: Fantasies, Dreams, Myths, and Realities Catherine DeAngelis, MD (AJDC. 1991;145:49-52). Influence of Otitis Media on the Correlation Between Rectal and Auditory Canal Temperatures Thomas E. Terndrup, MD, Agnes Wong, MD (AJDC. 1991;145:75-78). Cat-Scratch Disease: Acute Encephalopathy and Other Neurologic Manifestations Hugh A. Carithers, MD, A. M. Margileth, MD (AJDC. 1991;145:98-101).
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