Evaluation of stability after orthognathic surgery with minimal orthodontic preparation: comparison according to 3 types of fixation.

CLINICAL STUDY

Evaluation of Stability After Orthognathic Surgery With Minimal Orthodontic Preparation: Comparison According to 3 Types of Fixation Ji-Young Lee, DDS,* Young-Kyun Kim, DDS, PhD,*Þ Pil-Young Yun, DDS, PhD,* Nam-Ki Lee, DDS, PhD,þ Jong-Wan Kim, DDS, PhD,þ and Joon-Ho Choi

Abstract: This study was performed to evaluate the patterns and amount of postsurgical relapse after mandibular setback surgery with minimal orthodontic preparation. We also compared the stability of plate according to types. From January 2009 to February 2012, 26 patients (13 males, 13 females) at Seoul National University Bundang Hospital were identified. All patients underwent presurgical orthodontic treatment in less than 6 months and had mandibular setback surgery. Lateral cephalograms were taken presurgically (T0), immediately after surgery (T1), and 6 months after surgery (T2). To evaluate surgical change and surgical relapse, linear and angular measurements were performed, and results were analyzed. Comparison of the vertical and horizontal relapses between groups (group 1: sliding plate, group 2: conventional metal plate, group 3: resorbable plate) was also performed. The overall mandibular relapse was 2.80 (SD, 3.86) mm (pogonion) and 3.85 (SD, 4.44) mm (menton) anteriorly, and 1.2 (SD, 3.39) (pogonion) and 1.47 (SD, 3.48) mm (menton) superiorly. There was no significant difference among the 3 groups, however (P 9 0.05). When mandibular setback surgery was performed, surgical relapse would occur anteriorly and superiorly. Significant difference can hardly be found among the 3 groups in terms of the amount of vertical and horizontal relapses. Key Words: Minimal orthodontic, plate, relapse, setback

orthognathic surgery is done smoothly by leveling and adjusting the width of the maxillary and mandibular arches. However, most of the patients consider it to be most uncomfortable because of the orthodontic appliance’s poor aesthetics, pain, and long duration of treatment.1,2 Nowadays, doctors often perform orthognathic surgery first or early surgery wherein such uncomfortable orthodontic treatment before surgery is eliminated or minimized. These procedures shorten the total treatment duration significantly and have none of the problems such as deterioration of facial deformity. In addition, it can also improve the face of the patient rapidly by performing orthognathic surgery first.3 Previous studies show that orthognathic surgery first or early surgery has shortened the total treatment duration and proven to be very satisfactory in rapidly improving the faces of patients.3,4 Many kinds of methods and materials were introduced to fix the proximal segment after implementing bilateral sagittal splitting ramus osteotomy (BSSRO). Although each of them has its pros and cons, many studies in the past have reported that monocortical plate fixation was similar to bicortical fixation in terms of stability.5,6 For the fixation plate, metal plate or resorbable plate was widely used; a sliding plate with a sliding hole on the mesial side has been introduced.7 There are studies that researched on the stability of each plate, but few comparative studies on the stability of the plate in early surgery. This study aims to evaluate facial vertical and horizontal changes after early orthognathic surgery and analyze stability of 3 kinds of plates.

(J Craniofac Surg 2014;25: 911Y915)

MATERIALS AND METHODS

O

rthognathic surgery consists of 3 steps: presurgical orthodontic treatment, orthognathic surgery, and then postsurgical orthodontic treatment. In particular, orthodontic treatment requires a long period, although orthodontic treatment before surgery arranges teeth ideally, removes dental compensation, and ensures that the process of

From the Departments of *Oral and Maxillofacial Surgery and †School of Dentistry, Seoul National University; and ‡Orthodontics, Section of Dentistry, Seoul National University Bundang Hospital, Seoul, Korea. J.-H.C. is a 10th-grade student at The Hill School, Pottstown, Pennsylvania. Received June 21, 2013. Accepted for publication November 17, 2013. Address correspondence and reprint requests to Young-Kyun Kim, DDS, PhD, Department of Oral and Maxillofacial Surgery, Section of Dentistry, Seoul National University Bundang Hospital, 300 Gumi-dong, Bundang-gu, Seongnam city, Gyunggi-do, Korea; E-mail: [email protected] The authors report no conflicts of interest. Copyright * 2014 by Mutaz B. Habal, MD ISSN: 1049-2275 DOI: 10.1097/SCS.0000000000000609

The Journal of Craniofacial Surgery

We secured radiographs before surgery, immediately after surgery, and 6 months after surgery of patients who had mandibular orthognathic surgery for mandible setback from January 2009 to February 2012 at Seoul National Bundang Hospital. The study involved 26 patients (men, 26; women, 13) who went through early surgery wherein the duration of treatment before surgery was less than 6 months. This study was conducted with the approval of Seoul National University Bundang Hospital’s institutional review board (IRB:b-1111-139-114). The surgeries were performed by 2 oral and maxillofacial surgeons whose clinical career exceeded 15 years; orthodontic treatment was performed by 2 orthodontists whose clinical career exceeded 10 years. The average age of the patients was 25.73 (SD, 5.19) years. After giving patients general anesthetic and orofacial painting, surgeons placed 8 titanium screws into the maxillary and mandibular buccal cortical bone (Dual top anchor system; Jeil Medical Corporation, Seoul, Korea/ screw, APIS plate; Tradimedics, Gwang-Ju, Korea). The surgical method was BSSRO.8,9 After the setback of the mandible, wafer was mounted, and intermaxillary fixation was done by wire. After manual repositioning was performed without condyle positioning devices, monocortical fixation was done using 3 kinds of plates in proximal and distal segments. Following the trimming of the ramus anterior border and

& Volume 25, Number 3, May 2014

Copyright © 2014 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.

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Lee et al


FIGURE 1. Reference planes: FH plane (Or-Por), S-perp. Por indicates porion; Or, orbitale.

removal of intermaxillary fixation, wound closure was performed. On the next day of the surgery, intermaxillary fixation was done by wire on 8 titanium screws that had been implanted into the maxillary and mandibular buccal cortical bone. The intermaxillary fixation period was 2 to 3 weeks, with orthodontic treatment performed immediately after the removal of the intermaxillary fixation. Lateral cephalometric analysis was done based on radiographs taken 1 month before surgery (T0), immediately after surgery (T1), and 6 months after surgery (T2). The radiological measurement was analyzed using V-ceph program (Cybermed, Seoul, Korea). Lateral cephalometric analysis was performed by the first author (J.-Y.L.), who did not perform the surgery to avoid the observer bias; the average value of the 2 measurements was then used. The change after surgery (T1YT0) and relapse 6 months after surgery (T2YT1) were evaluated through vertical, horizontal, and angle measurements on the radiograph (Figs. 1Y3).


FIGURE 3. Angular measurement: angles between the selected planes and FH plane: 1. FH to Ar-Pog, 2. FH to Ar-Me.

As the measuring point that evaluates the horizontal and vertical locations of the mandible, pogonion (Pog) and menton (Me) were used. For vertical measurement, the distances from the Frankfort horizontal (FH) plane to Pog and Me were measured; for horizontal measurement, the distances from Pog to S-perp (perpendicular line of sella to FH plane) and from Me to S-perp were measured. For angle measurement, the angle made by FH plane, articulare (Ar)YPog plane, and Ar-Me plane was measured. According to plate, they were divided into the first group (sliding plate, APIS plate; Tradimedics, Gwang-Ju, Korea), second group (conventional metal plate, Leforte system; Jeil Medical Corporation, Seoul, Korea), and third group (resorbable plate, Biosorb FX; ConMed Linvatec Biomaterials Ltd, Largo, FL); the horizontal and vertical relapses were then compared (Figs. 4Y6). The comparison of changes after surgery (T1YT0) and relapse after surgery (T2YT1) in each group were examined using the KruskalWallis test (SPSS version 15.0; SPSS, Chicago, IL) with significance level of P G 0.05.

RESULTS The average duration of treatment before surgery was 2.72 (SD, 1.82) months. The test subjects were as follows: 8 patients in the first group, 10 patients in the second group, and 8 patients in the third group. Table 1 shows the skeleton pattern before surgery. The measurement values of each group did not have a statistically significant difference (P 9 0.05). The average orthodontic treatment duration before surgery was 3.07 (SD, 1.91) months for group 1, 2.75

FIGURE 2. Horizontal measurement (in mm) and vertical measurement (in mm)Vdistances between the selected points and line perpendicular to FH plane from sella (S): 1. S-perp to Pog, 2. S-perp to Me; distances from FH plane to the selected points: 3. FH to Pog, 4. FH to Me.

912

FIGURE 4. Sliding plate used in group 1 (APIS plate; Tradimedics).

* 2014 Mutaz B. Habal, MD




Stability After Orthognathic Surgery

TABLE 1. Comparison of Horizontal and Vertical Positions of the Mandible in the Presurgical (T0) Stage and Duration of Presurgical Orthodontics Between Groups Group 1 (n = 8)

FIGURE 5. Metal plate used in group 2 (Leforte system; Jeil Medical Corporation).

(SD, 1.82) months for group 2, and 2.34 (SD, 1.89) months for group 3. Again, the orthodontic durations before the surgery of each group did not have a statistically significant difference (P 9 0.05). Change after surgery (T1YT0, surgical change) was evaluated with the average value of 2 items ($S-perp to Pog, $S-perp to Me). Postsurgery horizontal changes were j12.99 (SD, 3.23) mm for the first group, j9.64 (SD, 1.53) mm for the second group, and j13.59 (SD, 1.45) mm for the third group. There was no significant difference among those 3 groups as a result of the statistical examination of each item, however. For vertical changes, the first group showed j0.14 mm; the second group, 0.53 mm; and the third group, j1.82 mm. Angle changes were 4.23 degrees for the first group, 2.81 degrees for the second group, and 3.57 degrees for the third group in $FH to Ar-Pog. There was no statistically significant difference among the 3 groups, however (P 9 0.05, Table 2). The relapse after surgery was 2.45 (SD, 3.27) mm (Pog) and 3.55 (SD, 4.12) mm (Me) frontward and 1.2 (SD, 3.39) (Pog) and 1.47 (SD, 3.48) mm (Me) upward. Frankfort horizontal to Ar-Me showed reduction of 1.47 (SD, 3.48) degrees. In other words, the mandible moved forward-upward as postsurgery relapse. Horizontal relapse (T2YT1) was 2.97 mm in the first group and 3.86 and 1.94 mm in the second and third groups, respectively. There was no statistically significant difference among the 3 groups, however (P 9 0.05, Table 3). Vertical relapse (T2YT1) was j1.72 mm in the first group and j1.44 and j0.92 mm in the second and third groups, respectively. As a result of angle measurement, the first and second groups turned forward-upward by j1.64 and j1.72 degrees, and the third group, by j0.41 degrees. There was no significant difference among the 3 groups, however (P 9 0.05, Table 3).

DISCUSSION Although there are many complications such as temporomandibular joint (TMJ) dysfunction, paresthesia, and unsatisfactory aesthetic result, relapse is one of the most serious complications. Relapse

S-perp to Pog, mm S-perp to Me, mm FH to Pog, mm FH to Me, mm FH to Ar-Pog, degrees FH to Ar-Me, degrees Presurgical orthodontic period, mo

Group 2 (n = 10)

Group 3 (n = 8)

Mean

SD

Mean

SD

Mean

SD

P*

76.27 70.64 97.2 104.58 43.18

3.75 4.19 2.23 2.04 1.34

75.7 67.34 97.46 104.95 42.92

1.94 2.16 2.39 2.24 1.01

81.38 73.49 101.4 110.48 41.97

3.4 3.35 2.94 2.57 1.9

NS NS NS NS NS

47.52

1.53

48.1

0.95

47.2

1.73

NS

3.07 (1.91)

2.75 (1.82)

2.34 (1.89)

NS

*Kruskal-Wallis test. NS indicates nonsignificant.

occurs when the mandible moves forward by more than 1.5 mm than the maxillary dentition in normal occlusion after surgical treatment in the case of mandibular prognathic.10 Relapse is influenced by various factors such as presurgical orthodontic treatment, accuracy of osteotomy, amount of movement, tension of muscle, location change of the mandibular condyle, and fixation method of bone fragment.11,12 Moreover, some studies show that most of the changes of Pog occur within 6 months of surgery.13 As a result of the comparison using lateral cephalometric analysis 6 months after the surgery in this study, the first group (sliding plate) showed 15% horizontal movement as relapse, with the second group (conventional metal plate) and the third group (resorbable plate) exhibiting 30% and 14%, respectively. Studies in the past showed the relapse rate after BSSRO to be 6% to 70%, although it varies by study design or researcher.14Y16 According to 1 research, the miniplate group showed 2% to 18% relapse, whereas the bicortical screw exhibited 10% to 17%.17 The result of this study was similar to those of the past studies. It is noteworthy, however, that the conventional metal plate group’s relapse rate was a little higher than those of the other groups. This is due to the small number of evaluation subjects and variations in numbers. Likewise, Rodrı´guez and Gonza´lez18 reported the relapse rate 6 months after surgery to be about 26% of the setback amount in mandible setback surgery. As a result of evaluation of the relapse rate 6 months after the surgery, there was no statistically significant difference among the plates.

TABLE 2. Surgical Change (T1YT0) Cephalometric Analysis Group 1 (n = 8)

$S-perp to Pog, mm $S-perp to Me, mm $FH to Pog, mm $FH to Me, mm $FH to Ar-Pog, degrees $FH to Ar-Me, degrees

FIGURE 6. Resorbable plate used in group 3 (Biosorb FX; ConMed Linvatec Biomaterials Ltd).

Group 2 (n = 10)

Group 3 (n = 8)

Mean

SD

Mean

SD

Mean

SD

P*

j12.79 j13.2 j0.25 j0.04 4.23 4.74

3.05 3.41 1.62 1.59 1.51 1.71

j9.59 j9.69 0.65 0.41 2.81 3.07

1.51 1.55 1.6 1.58 0.65 0.59

j13.97 j13.22 j1.7 j1.95 3.57 3.67

1.39 1.51 1.68 0.99 1.06 0.88

NS NS NS NS NS NS




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Lee et al

TABLE 3. Relapse Change (T2YT1) Cephalometric Analysis Group 1 (n = 8)

$S-perp to Pog, mm $S-perp to Me, mm $FH to Pog, mm $FH to Me, mm $FH to Ar-Pog, degrees $FH to Ar-Me, degrees

Group 2 (n = 10) Mean

SD

Group 3 (n = 8)

Mean

SD

Mean

2.3 3.65 j1.36 j2.07 j1.26

1.06 3.02 1.05 1.89 1.14 4.71 1.33 2 0.93 j1.51 1.56 j0.83 0.7 j1.37 1.66 j1.01 0.79 j1.39 0.48 j0.33

SD

Total (n = 26) Mean

SD

P*

1.33 2.45 3.27 NS 1.68 3.55 4.12 NS 0.53 j1.20 3.39 NS 0.61 j1.47 3.48 NS 0.85 j1.03 2.03 NS

j2.01 0.85 j2.05 0.47 j0.49 0.95 j1.47 3.48 NS


The overall directions of relapse were forward or upward, with the mandible showing a tendency toward counterclockwise rotation. According to Lee et al,19 as a result of the study on the relapse tendency of 15 patients who underwent mandible setback surgery after minimum orthodontic treatment, the relapse direction was forward-upward, and the vertical relapse was caused by rotation with mandibular horizontal relapse. Therefore, they stressed that this should be considered during presurgical orthodontic treatment.19 The titanium plate is widely used in fixation because of its resistance to corrosion and high biocompatibility as well as minimal scatter in computer tomography.20,21 Still, some were of the opinion that titanium particles were found in the upper soft tissue or surrounding lymphatic tissue and that the plate should be removed after stabilizing the fracture fragment. Studies also suggested long-term complications such as thermal conductivity and unacceptable palpability in sensitive patients, possibility of antritis, allergic response, or infection.22Y28 Therefore, it has a drawback; that is, a second surgery is needed to remove the plate. Matthew and Frame29 reported the plate removal rate to be an average of 13% (minimum of 5%, maximum of 40%) from a survey of 23 oral and maxillofacial surgeons. Resorbable materials, which were developed to overcome the drawback of the metal plate, has an advantage of eliminating the need for a second surgery for removal. There is also less risk of weakening of the fixed bone due to stress shielding and no risk of metallic corrosion.30,31 Nonetheless, there is a high risk of micromovement in fixed bone due to delayed foreign body reaction, osteolytic change, mechanical weakness, and relatively low stability.32Y34 According to Wittwer et al,35 there was no significant difference between resorbable and titanium fixation materials in terms of fracture cure and result of surgery. Moreover, Bos et al36 reported that resorbable PLLA plate could maintain good stability during sufficient period of fracture healing. Harada and Enomoto37 stated that there was no significant difference between resorbable plate and metal plate as a result of studying the relapse after orthognathic surgery. The 2.4-mm resorbable plate used in this study was composed of PDLLA (70L/30DL polymer). Mechanical strength was maintained for about 22 weeks, with absorption proceeding for about 24 to 30 months. In the cases of this study, complications such as infection or early plate fracture were not observed. The sliding plate was designed to compensate for early relapse with its oval-type holes that suit distal segment; thus, the mislocated condyle during surgery moves through. According to Baek and Lee,7 they had obtained a stable surgery result without any complication such as early relapse of TMJ when they performed mandible setback surgery using a sliding plate on 23 patients. They also claimed that the sliding plate minimized early relapse by allowing the mislocated

914


condyle during the TMJ positioning of the surgery to be repositioned through the gap of its distal area.7 Similarly, in this study, 8 patients on whom the sliding plate was used did not exhibit complications such as TMJ pain or early relapse but exhibited stable results after the surgery. In this study, for horizontal and vertical relapses, linear and angular measurements were taken based on Pg and Me. As a reference point, existing studies were used; the aforesaid method was used because it was considered a relatively reasonable tool in evaluating sagittal skeletal changes and vertical location changes.19 One drawback of this study was the difficulty in obtaining a statistically significant result due to the small number of cases per group. Moreover, the influence of operators could not be excluded because 2 surgeons and 2 orthodontists were involved in the treatment. Therefore, future analysis should be based on multiple cases handled by 1 surgeon and 1 orthodontist. Relapse after surgery is deemed to occur forward-upward while performing mandible setback surgery using BSSRO; for relapse after surgery, using 3 kinds of plates can be expected to obtain a stable result.

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Stability After Orthognathic Surgery

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Orthodontic preparation for orthognathic surgery.

Evaluation of stability after pre-orthodontic orthognathic surgery using cone-beam computed tomography: A comparison with conventional treatment.

Anchor Plate Efficiency in Postoperative Orthodontic Treatment Following Orthognathic Surgery via Minimal Presurgical Orthodontic Treatment.

Stability after Cleft Maxillary Distraction Osteogenesis or Conventional Orthognathic Surgery.

Skeletal stability of bioresorbable fixation in orthognathic surgery: a systemic review.

Evaluation of the nasal shape after orthognathic surgery.

Evaluation of Patients' Satisfaction after Class III Orthognathic Surgery.

Evaluation of pharyngeal airway space changes after bimaxillary orthognathic surgery with a 3-dimensional simulation and modeling program.

Incidence of bracket failure during orthognathic surgery: a comparison of two techniques to establish interim maxillomandibular fixation.

Steroid acne after orthognathic surgery.

A 3-year evaluation of skeletal stability of mandibular advancement with rigid fixation.

Esthetic arch bar for maxillomandibular fixation in orthognathic surgery.

Three-dimensional investigation of facial surface asymmetries in skeletal malocclusion patients before and after orthodontic treatment combined with orthognathic surgery.

Maxillary hypoplasia in the cleft patient: contribution of orthodontic dental space closure to orthognathic surgery.

Rigid fixation in orthognathic surgery: a personal appraisal.

A method for evaluating skeletal relapsing force during maxillomandibular fixation after orthognathic surgery: a preliminary report.

Miniscrews versus surgical archwires for intermaxillary fixation in adults after orthognathic surgery.

Fixation Stability Measurement Using Two Types of Microperimetry Devices.

Comparison between efficacy of four different types of orthodontic separators.

Satisfaction of skeletal class III patients treated with different types of orthognathic surgery.

Comparison of Anesthetic Administration According to Method of Hip Surgery.

Comparative study of postoperative stability between conventional orthognathic surgery and a surgery-first orthognathic approach after bilateral sagittal split ramus osteotomy for skeletal class III correction.

Biodegradable and Titanium Osteosynthesis Provide Similar Stability for Orthognathic Surgery.

Comparison of Different Types of Complications in the Phacoemulsification Surgery Learning Curve According to Number of Operations Performed.