ORIGINAL ARTICLE
Unilateral Mandibular Hypoplasia in Adult Patients: Distraction Osteogenesis and Conventional Osteotomies in a Standardized Sequence Giovanni Gerbino, MD, DDS,* Francesca Antonella Bianchi, MD,* Laura Verzé, MD,† and Guglielmo Ramieri, MD, DDS* Introduction: This study analyzed the outcomes of nongrowing patients with unilateral mandibular hypoplasia treated according to a specific protocol, which combines distraction osteogenesis, orthodontic treatment, and conventional osteotomies. Materials and Methods: The patients treated were objectively evaluated. Patient’s satisfaction was assessed by questionnaire. Surgical changes were analyzed using cephalometry and three-dimensional facial surface data before surgery (T0) and at long-term (T1) follow-up. Results: Four patients were included in this study. The normalization of facial proportion and a high increase in symmetry were evident. Residual defects were documented in the postoperative symmetry of the chin. In the questionnaire, all patients gave favorable responses to their facial changes; for most of the objective parameters, all patients improved. Conclusions: A multistage treatment protocol for the correction of facial deformities in patients with unilateral mandibular hypoplasia is a valid procedure for skeletal and occlusal stability. An evident improvement of the facial appearance is also achieved. Key Words: Unilateral mandibular hypoplasia, facial asymmetry, osteogenesis, conventional orthognathic surgery, three-dimensional surface laser scanner
resulting in facial deviation with a combination of a retrognathic mandible deviated toward the ipsilateral side with chin point deviation, canting of the occlusal plane with hypoplasia of the ipsilateral maxilla, gonion, and lips asymmetry. These clinical features can be found both in patients with lack of neural crest cells migration, such as hemifacial microsomia (HFM) types 2a to 2b,1–3 and in patients with growth abnormalities due to trauma, infections, or surgical iatrogenic deformities, which occurred in the condylar region during late fetal or postnatal development.4,5 Restoration of facial symmetry, in adult patients with UMH, regardless of the etiology (ie, congenital, developmental, or acquired) continues to be a challenging procedure for craniofacial surgeons.6 Autogenous bone grafts,7–12 conventional orthognathic surgery,13,14 distraction osteogenesis,15–19 and temporomandibular joint (TMJ) prostheses20,21 have been proposed as surgical solutions for the correction of a curvilinear facial profile. The purpose of this prospective study was to evaluate the outcomes of nongrowing patients with UMH treated according to a specific protocol, which combines, in a standardized sequence, distraction osteogenesis, orthodontic treatment, and conventional maxillomandibular osteotomies. The specific aim of the study was to assess the amount of correction achieved by cephalometric analysis, three-dimensional analysis of the soft tissue changes, and clinical evaluation.
MATERIALS AND METHODS
(J Craniofac Surg 2014;25: 1959–1966)
U
nilateral mandibular hypoplasia (UMH) is characterized by asymmetric underdevelopment of the mandibular condyle and ramus What Is This Box? A QR Code is a matrix barcode readable by QR scanners, mobile phones with cameras, and smartphones. The QR Code links to the online version of the article.
From the *Division of Maxillofacial Surgery, Surgical Sciences Department, San Giovanni Battista Hospital, and †Department of Science of Public Health and Pediatrics, University of Turin, Turin, Italy. Received July 28, 2013. Accepted for publication March 13, 2014. Address correspondence and reprint requests to Francesca Antonella Bianchi, MD, Division of Maxillofacial Surgery, Surgical Sciences Department, San Giovanni Battista Hospital, University of Turin, Corso A.M. Dogliotti 14, 10126 Torino, Italy; E-mail: [email protected] The manuscript is not under consideration by another journal, nor has it been previously published. The authors report no conflicts of interest. Copyright © 2014 by Mutaz B. Habal, MD ISSN: 1049-2275 DOI: 10.1097/SCS.0000000000000975
From January 2004 to June 2010, 6 patients with UMH received a specific treatment protocol, which combined distraction osteogenesis, orthodontic treatment, and conventional orthognathic surgery at the Division of Maxillofacial Surgery, San Giovanni Battista Hospital, University of Turin, Turin, Italy. All patients had the following features: (1) hypoplasia of the mandibular condyle and ramus, (2) retrognathic mandible deviated toward the ipsilateral side, (3) canting of the occlusal plane and lips, and (4) hyperdivergent facial morphology (Fig. 1). Inclusion criteria were nongrowing patients with UMH and complete records before surgery (T0), after each phase of surgical protocol (Tx), and at the longest follow-up (T1). Exclusion criteria were evidence of continued growth; hystory of craniofacial injury or craniofacial syndrome; and incomplete clinical and radiologic records at T0, Tx, and T1. Thus, 4 white adult subjects with UMH were enrolled in the study. Patients presented UMH with right (1 patient) or left (3 patients) lateral (L) deviation. Sagittal and vertical jaws’ discrepancies and malocclusion are described in Tables 1 and 2. The treatment protocol consisted of (1) intraoral distraction of the ascending ramus with the support of individual prefabricated occlusal splint and guiding elastics, (2) postdistraction orthodontic treatment to prepare for conventional osteotomies, (3) conventional orthognathic surgery (combined Le Fort I osteotomy, bilateral sagittal split osteotomy) at least 1 year after completion of the distraction period, and (4) postsurgical orthodontic treatment.
The Journal of Craniofacial Surgery • Volume 25, Number 6, November 2014
Copyright © 2014 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
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Surgical Procedures Three-dimensional multislices computerized tomography scans were used for planning the distraction phase. In the first 2 cases, stereolithographic models were used for the simulation of distraction vector and the resulting mandibular repositioning. Under general anesthesia, a unidirectional distraction device was positioned, through an intraoral approach, on the L face of the ascending ramus, with screws placed through a transbuccal trocar. The distraction vector was vertical to achieve elongation of the ascending ramus, that is, the major axis of the distractor was parallel or with an angle inferior to 45 degrees to the posterior border of the ascending ramus. The planned osteotomy line was perpendicular to the distraction vector. After a corticotomy of the posterior border, lateral cortex, and anterior border, complete fracture of the ascending ramus was performed, leaving the neurovascular bundle intact and the lingual periosteum attached. The internal distraction device was fit in place, fixed, and activated to ensure free movement of the bone segment. The wound was closed in layers. All patients were treated with oral antibiotics for 6 postoperative days. Distraction was begun after a latency period of 6 days; performed at a rate 0.4 mm, 2 times daily; and continued until the planned position, including overcorrection, was achieved. During the activation phase, an individual prefabricated occlusal splint was used to support the development of an ipsilateral open bite. Guiding elastics were used to avoid a midline shift to the controlateral side. At the weekly control visits during the active distraction phase, the stabilization splint was corrected. During the distraction phase, radiographic and clinical examinations were done at follow-up visits. The consolidation period was 9 weeks (range, 6–12 w), after which the distraction devices were removed under general anesthesia. During the consolidation phase, the supporting occlusal splint with bite blocks was used to mantain the unilateral open bite. A conventional postdistraction presurgical fixed orthodontic treatment was started. Treatment objectives were leveling and alignment of the maxilla and elimination of dental compensations with coincidence of the dental midline with the bony mandibular midline. At least 1 year after completion of the distraction period and after an adequate orthodontic preparation, conventional orthognathic surgery was performed to adjust three-dimensional residual dentoskeletal discrepancies. In all patients, combined Le Fort I osteotomy, bilateral sagittal split osteotomy, and additional procedures (genioplasty and/or rhinoplasty) were required to correct any maxillary and mandibular
FIGURE 1. Patient 2. A and B, A 17-year-old female adolescent had the clinical features of the right-side UMH (facial asymmetry, retrognathic mandible deviated toward the ipsilateral side with chin point deviation, canting of the occlusal plane, gonion, and lips asymmetry). C and D, Three-dimensional and coronal computerized tomography scans showing asymmetric underdevelopment of the right mandibular condyle and ramus.
Additional procedures (genioplasty and/or rhinoplasty) were performed at the same surgical time of conventional maxillomandibular osteotomies or delayed (6 months later) (Table 1). Posteroanterior (PA) and L cephalometry and three-dimensional facial surface data were obtained before distraction (T0) and at the longest follow-up (T1). Clinical evaluation was performed at T0 and T1, and patients’ satisfaction with facial appearance after surgery was subjectively evaluated by a questionnaire. Informed consent was obtained from all participants. This study was performed in agreement with a local institutional review board. We followed the Helsinki Declaration guidelines.
TABLE 1. Patient’s Pathology Description and Problems Concerning Their Occlusion and Surgical Treatment Pathology Etiology of facial Patients Sex Age, Y asymmetry
Mandible L Direction of Maxilla Inclination of Anterior Posterior Trasversal Vertical problems palatal Deviation (mm) mandible L superior the occlusal crossbite crossbite defect plane deviation rotation
1
F
18
Congenital: HFM 2a
11
2
F
17
7
3
M
19
4
M
17
Acquired: neonatal arthritis Acquired: neonatal arthritis Acquired: neonatal arthritis
11
6
Left (left mandibular hypoplasia) Right (right mandibular hypoplasia) Left (left mandibular hypoplasia) Left (left mandibular hypoplasia)
Yes
Yes
-
-
-
-
Yes
Yes
-
-
-
Yes
Yes
-
Yes
Yes
Yes
-
-
Surgery
Follow-Up (T1), Mo
Left MD, C, G + RSP
32
Deep bite
Right MD, C+G
24
Yes
-
Left MD, C+G
49
-
Deep bite
Left MD, C + G + RSP
40
Hyphen (-) indicates absence of some defects. MD, mandible distraction; C, combined maxilla-mandible surgery; RSP, rhinoplasty; G, genioplasty.
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© 2014 Mutaz B. Habal, MD
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The Journal of Craniofacial Surgery • Volume 25, Number 6, November 2014
Unilateral Mandibular Hypoplasia
TABLE 2. Measurements of L and PA Cephalograms Patient 1
L Cephalometry
PA Cephalometry
Posterior facial height (Go-CF), mm Ramus position, degrees Maxillary depth (FH-NA)N, degrees Facial angle (FH-Npo), degrees Facial axis-Ricketts (NaBa-PtGn), degrees Convexity (A-Npo), mm U-incisor protusion (U1-Apo), mm U1-FH, degrees U-incisor inclination (U1-Apo), degrees L1 protrusion (L1-Apo), mm L1 to A-Po, degrees Mandibular incisor extrusion, mm Overjet, mm Overbite, mm Dental midline discrepancy, mm Maxillomandibular midline, mm Occlusal plane tilt, degrees Postural symmetry, degrees Maxillary width, mm Mandibular width, mm Facial width, mm A-Me-MSR, degrees
Patient 2
Patient 3
Patient 4
Normal Values*
T0
T1
T0
T1
T0
T1
T0
T1
60.1 (3.3) 76 (3) 90 (3) 88.6 (3) 90 (3.5) 0.7 (2) 3.5 (2.3) 111 (6) 28 (4) 1 (2.3) 22 (4) 1.2 (2) 2.5 (2.5) 2.5 (2) 0 (1.5) 0 (2) 0 (2) 0 (2)
48.8 61.9 81.5 76.2 78.4 5 8 100.3 29.6 3.1 26.6 1.6 4.5 3.1 −0.1 12.6 −8.7 −0.4 64 83 118.9 11
62.2 75.1 92.3 85.2 82 7.6 10.9 108.6 30.9 4.9 26.3 −0.2 3 0.5 −0.6 5.9 0 −1.4 60.1 89 117.8 2
53.6 70.9 92.1 84 79.6 7.7 9.3 103.2 27.5 3.9 26.4 2.6 5 5.2 1.8 −6.2 8.6 2.6 61.1 83.7 117.5 7
64.1 83 94.7 87.6 83.9 7.1 8.9 114.3 34.9 6.6 33.2 1.6 2 3 −0.6 0.5 0 −1.2 52.3 77.4 98.9 0.5
62.4 61.9 79.2 70.8 77.5 10 17.3 112 51.5 −1.8 13.4 3.6 10 3 0.8 10.8 −3.8 −6.6 57.3 92.9 118.6 11
74.3 69.5 78 70.8 79.9 8.5 7.3 88.6 26.7 1.7 24.4 0.9 5 2 −0.2 −1.4 0 −4.2 62.8 92.3 119.8 2
59.8 54.3 73.3 68.4 78.7 5.5 10.2 86.5 23.5 7.3 27.3 1.3 3 4.6 0.7 6 −8.7 −1.5 75.5 102.3 144.2 6
75.6 61.6 79.4 73.7 80.2 6.8 4.7 87.1 20 2.4 34.7 0.1 2 2 −0.4 3.1 0 1.8 70.5 104.2 141.4 3
0 (2)
*Values are mean (SD).
deformities and to achieve better symmetry. Postsurgical orthodontic treatment was essential for all patients to attain optimal results.
30.000 points. Facial surface reconstruction, multiple scan alignment, and measurements were carried out using Rapid Form 2004 software (INUS Technologies Inc, Seoul, South Korea).
Cephalometric Measurements The PA and L cephalograms were traced by 1 examiner using the software Dolphin 11.0 Premium (Dolphin Imaging, Chatsworth, CA). The following measurements were obtained to assess sagittal, vertical, and transversal skeletal and dental movements: posterior facial height (Go-CF), ramus position, maxillary depth (FH-NA) N, facial angle (FH-NPo), facial axis-Ricketts (NaBa-PtGn), convexity (A-NPo), U-incisor protusion (U1-APo), U1-FH, U-incisor inclination (U1-APo), L1 protrusion (L1-APo), L1 to A-Po, mandibular incisor extrusion, overjet, overbite, dental midline discrepancy, maxillomandibular midline, occlusal plane tilt, postural symmetry, maxillary width, mandibular width, facial width, and A-Me-MSR (Table 2). A subsample of 8 randomly selected radiographs were retraced and digitized 1 month later to calculate the systematic errors. All the angular and linear measurements were compared between the 2 time sets by paired t-test. All the measurements presented no significant difference at retracing.
Facial Scan and Data Processing Facial surface data were acquired using a Head and Face Color 3D Scanner (3030RGB; Cyberware, Inc, Monterey, CA). All subjects were registered with the head in natural position, the eyes closed, and the teeth in occlusion. The scanning method took into consideration previous observations concerning the positioning of the subject and environmental conditions. The detailed protocol to reduce the artifacts was previously described.22 The acquired data were transferred to a graphics workstation for viewing and elaboration with Cyberware Echo software (Cyberware Inc, Monterey, CA). Scanned data sets were first restricted to the facial area and then reduced from around 160.000 to
FIGURE 2. Top, Virtual optimal female face F. Bottom, Virtual optimal male face M. A and C, Frontal views with horizontal and vertical reference planes. B and D, Profile views.
© 2014 Mutaz B. Habal, MD
Copyright © 2014 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
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TABLE 3. Point-to-Point Distances of the Landmarks Considered Patient 1 Distances Symmetry
Vertical
Transversal
Angles
enr–alr enl–all enr–chr enl–chl alr–chr all–chl sn–chr sn–chl alr–x all–x chr–x chl–x sn–ls li–pg sn–pg pg–x chr–sn–chl chr–pg–chl alr–y all–y chr–y chl–y pg–y Nasolabial angle Labial-mental angle
Patient 2
Patient 3
Patient 4
F
T0
T1
T0
T1
M
T0
T1
T0
T1
36.33 36.93 62.98 63.05 31.35 31.50 37.82 37.71 36.35 36.05 61.27 61.21 13.78 22.69 50.03 89.24 85.68 81.24 14.25 14.98 25.66 26.02 0 132.83 143.55
36.48 37.28 63.80 59.57 35.02 26.63 35.52 33.52 32.66 30.93 62.95 57.25 15.77 20.15 50.07 86.26 80.78 76.69 13.80 15.55 19.53 26.86 12.18 136.76 126.76
35.64 36.66 64.91 64.92 30.72 31.18 37.36 36.60 35.77 35.60 64.98 64.34 17.17 18.97 52.47 90.14 84.36 78.64 16.87 16.95 24.54 23.53 2.76 138.38 136.11
37.64 40.93 60.64 65.49 25.41 30.75 35.15 37.21 32.49 35.58 59.03 61.52 15.68 21.81 55.39 88.66 77.68 69.02 18.24 13.57 27.81 21.49 4.42 159.49 124.48
41.27 40.26 66.58 65.56 30.11 28.57 37.95 38.58 36.69 36.50 64.85 64.50 14.33 25.36 54.92 91.16 86.17 77.96 17.03 17.15 25.18 26.01 1.10 138.66 140.64
38.17 38.90 68.98 69.09 33.31 33.28 40.81 40.96 38.16 38.54 68.30 68.42 15.69 22.38 54.80 98.84 86.31 83.87 18.37 17.92 26.73 26.91 0 134.57 139.06
40.98 44.39 70.89 68.93 32.80 31.70 38.66 37.99 38.40 36.80 69.25 65.19 17.17 22.17 53.06 93.41 78.40 77.99 16.79 23.01 18.31 30.04 11.88 137.45 109.40
39.44 40.17 72.44 72.10 34.36 34.19 40.62 39.70 37.76 37.05 69.09 68.11 19.02 23.47 57.30 99.76 87.51 85.22 17.94 18.51 26.36 27.01 3.21 127.35 118.26
39.96 39.11 69.60 65.75 30.85 29.79 39.09 37.36 35.22 32.24 65.98 60.71 14.91 22.10 52.55 88.83 81.81 78.63 18.04 20.13 19.10 29.25 9.10 143.91 116.56
42.72 42.46 71.26 70.74 33.27 33.19 41.16 40.41 37.01 36.62 69.02 68.10 16.86 22.42 54.98 98.36 84.89 83.47 19.38 20.04 27.20 27.25 4.30 139.73 122.45
Values are in millimeters. F, virtual optimal female face; M, virtual optimal male face.
A virtual optimal male face M was constructed by averaging the scans of 40 healthy adult men, and a virtual optimal female face F was constructed by averaging the scans of 40 healthy adult women (Fig. 2).T0-T1, T0-F (for patients n = 1–2), T0-M (for patients n = 3–4), T1-F (for patients n = 1–2), and T1-M (for patients n = 3–4) were registered on homologous points. Reference vertical (midline through the glabella) and horizontal (through the right and left endocanthion) planes were constructed on the models (Fig. 2). Different linear and angular measurements were calculated for comparison of the T0 and T1 models using 10 landmarks taken from classic anthropometry. The landmarks were enr, right endocanthion; enl, left endocantion; alr, right alar crest point; all, leflt alar crest point; sn, subnasale; chr, righ cheilion; chl, left cheilion; ls, labialis superior; li, labialis inferior; and pg, pogonion (Table 3).
Clinical Evaluation and Patients’ Satisfaction At T0 and T1, all patients underwent a standardized evaluation consisted of aesthetic evaluation (facial symmetry, maxillomandibular chin position, lips posture, etc) and dental-periodontal assessment (clinical evaluation, periodontal probing, thermal test). At T0 and T1, each patient was asked to compare the photographs of their own face with the virtual optimal face F (patients 1 and 2) or M (patients 3 and 4) and then to complete a questionnaire to subjectively assess the perceptions of their facial appearance. The patients were invited to evaluate the following 5 parameters: (1) facial symmetry, (2) gonion symmetry, (3) chin position in frontal view, (4) chin position in profile, and (5) lips posture. All items were evaluated on numerical rating scales ranging from 1 to 10 (with 10 indicating the best imaginable appearance). The total patient score is obtained by adding the scores of each of the 5 items (range, 5–50), with higher
TABLE 4. Results of Surgical Treatment Pathology Patients 1 2 3 4
Mandible L Deviation, mm
Maxilla Superior Rotation
Inclination of the Occlusal Plane
Anterior Crossbite
Posterior Crossbite
Trasversal Palatal Defect
5* 0.5* 2* 3*
Yes
-
-
-
-
Vertical Problems Slight deep -
Absence (-) or persistence of some defects (*).
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The Journal of Craniofacial Surgery • Volume 25, Number 6, November 2014
FIGURE 3. Facial surface reconstruction of all 4 patients, at T0 and T1. Morphologic changes between T0 and T1 were investigated grossly as shell-to-shell deviation. The areas with major movement were represented in red; little movement, in green; and no movement, in blue. This provided information on local changes, as a false-color map (clearance vector map).
scores indicating the best imaginable facial appearance. The patients finally gave an overall opinion on their own facial appearance, with a score ranging from 1 to 10.
RESULTS Four patients, 2 women and 2 men, fullfilled inclusion criteria for the study. All patients were white adult subjects (mean age, 17.7 y; range, 17–19 y) with UMH. The mean follow-up duration was 36 months (range, 24–49 mo) (Table 1).
Cephalometric Measurements Cephalometric changes and clinical outcomes are summarized in Tables 2 and 4. The L measurements showed an increase in the posterior facial height and in ramus position and an improvement of the overjet and overbite. All patients had high values of convexity both at T0 and T1 (Table 2). The PA measurements revealed a normalization of the occlusal plane tilt and an improvement of maxillomandibular midline alignment and of the A-Me-MSR values (Table 2).
Unilateral Mandibular Hypoplasia
FIGURE 4. Patient 1. Left to right, Full face front view, front view with smile, and profile view. A–C, An 18-year-old woman had left-side UHM. D–F, Clinical views after unilateral mandibular distraction. G–I, The patient was seen at T1, after conventional orthognathic surgery and ancillary procedures (rhinoplasty and genioplasty).
Facial Scan and Data Processing The comparison of facial surface at T0 and T1 showed an overall increase in symmetry for all patients. Normalizations of the vertical and transversal positions of the labial commissures and of the nasal alae were evident. Increase in the sagittal projection of the lips and of the chin was also noticed. Reduced but still noticeable deviation of the chin on the symmetry axis (Y) was observed (Fig. 3). Measurements at T0 and T1 documented that the major postsurgical changes were in the lower area of the face (Table 3). After treatment, the distances of the lips from en (en-ch) were increased, and the distances of the lips from the columella (sn-ch) were normalized; a symmetrization between the 2 sides (right and left) was also evident. At T0, the al and ch points of the 2 sides demonstrated both vertical and horizontal asymmetries, particularly noticeable concerning the lips’ position. Symmetry of these measurements was significantly improved at T1 (Table 3).
TABLE 5. Subjective Evaluations Chin Facial Gonion Chin Position Position Symmetry Symmetry in Frontal View in Profile T0
T1
T0
T1
T0
T1
2.1 Range 1–4
7.2 6–8
1.9 1–3
6.8 5–8
2.8 1–5
8.2 6–10
Mean
T0
T1
Lips Posture T0
T1
Overall Opinion T0
T1
1.4 8.9 2.6 9.4 2.4 9.1 1–3 7–10 2–5 8–10 1–5 8–10
FIGURE 5. Patient 1. A, Occlusion before treatment. B, After distraction osteogenesis, bite blocks and occlusal splint were fundamental to achieve a good consolidation of the distracted bone before proceeding with leveling of the maxilla and with the latest surgical step. C, Occlusion at 32 months after treatment (T1).
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FIGURE 8. Patient 4. A, Occlusion before treatment. B, After distraction osteogenesis, bite blocks and occlusal splint were used before proceeding with the latest surgical step. C, Occlusion at 40 months after treatment (T1).
Clinical Evaluation and Patients’ Satisfaction
FIGURE 6. Patient 1. Left to right, PA cephalogram (top) and L cephalogram (bottom) before surgery (A and D), at the end of the distraction phase (B and E), and immediately after conventional osteotomies (C and F).
The long-term aesthetic result was satisfactory in all 4 patients. In particular, the positions of the labial commissures and the nasal alae were correct, and a great improvement of facial symmetry was evident. No tooth mobility, gingival bleeding, and nonvital teeth were noted. Two patients had evidence of varying degrees of gingival recession and radicular resorption. The results provided by patient score showed a substantial increase (from T0 to T1) of the scores of almost all of the items. In particular, all patients gave favorable scores to their postoperative chin position in profile, lips posture, and overall facial symmetry. Subjective evaluation results are reported in Table 5.
DISCUSSION Increased sustaining of the lips was also evident, without a visible enlargement of the intercommissural distance (chr-chl); instead, a slight nasal base flaring was observable (Table 3).
FIGURE 7. Patient 4. Left to right, Full face front view, front view with smile, and profile view. A–C, A 17-year-old male adolescent had left-side UHM. D–F, Clinical views after unilateral mandibular distraction. G–I, The patient was seen at T1, after conventional orthognathic surgery and ancillary procedures (rhinoplasty and genioplasty).
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An adverse event to the condylar region during late postfetal or early postnatal growth can result in abnormal growth and malformation of the mandible with UMH and facial deviation as a combination of tilted occlusal plane, chin point deviation, curved facial midline, gonion, and/or lips asymmetry. The mandibular shape in this group of patients is very similar to each other depending mainly on degree of the damage and the developmental stage of the mandible and seems almost independent of the type of the adverse event.4 The clinical skeletal features are very similar either to HFM 2a to 2b or pseudo-HFM. For this reason, we included in our study 3 patients who had condilar damage after neonatal infection arthritis and 1 patient with HFM 2a. All patients included in our study were referred to our institution after completion of the growth, and the protocol applied was designed for this kind of patients. Many options have been proposed for the surgical correction of HFM or pseudo-HMF. Conventional orthognathic surgery causes a high risk of relapse because of the large amount of movement23,24; furthermore, the pterygomasseteric sling prevents the successful mandibular vertical ramus lengthening and leads to unpleasant results.24,25
FIGURE 9. Patient 4. Left to right, PA cephalogram (top) and L cephalogram (bottom) before surgery (A and D), at the end of the distraction phase (B and E), and immediately after conventional osteotomies (C and F).
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The Journal of Craniofacial Surgery • Volume 25, Number 6, November 2014
The results, using autogenous bone grafts to increase the volume and size of hypoplastic ascending ramus, are often unpredictable.23 Undesirable remodeling of the graft can decrease the volume and strength of the reconstructed area.23 The grafting technique requires an extraoral approach and causes morbidity at the donor site26,27; moreover, this procedure is limited in volume and is often complicated by infection when alloplastic grafts are inserted.20,23 The distraction osteogenesis, first described for orthopedic surgery,28 has become increasingly popular for the treatment of facial asymmetries during the last 2 decades.15,16,29–31 One of the most significant advantages of distraction is the gradual lengthening of both hard and surrounding soft tissue envelopes.13,16,24,32–35 In growing patients, distraction osteogenesis with proper distraction vector planning, overcorrection, bite block, and guiding elastics can reestablish mandibular symmetry and prevent either occlusal canting or the restriction of vertical maxillary growth.15,17,24,34,36 Recently, studies based on cephalometric data showed that early distraction is successful in the short-term follow-up but leads to a gradual return to the original facial proportion at the long-term follow-up, expecially in true HFM.5,34,37–39 In adults, dental occlusion can be changed drastically by distraction osteogenesis and unacceptably prolonged, and difficult orthodontic treatment is required to achieve a satisfactory result.30,40–43 Scolozzi et al44 proposed the use of 2 independent distractors for a simultaneous maxillomandibular distraction osteogenesis without the use of intermaxillary fixation in the restorative treatment of HFM in adults, to avoid occlusal problems. Because our patients presented a retrognathic mandible, they would not have obtained a satisfactory correction of all the aesthetic defects by resorting to combined maxillomandibular distraction. Recently, Wolford et al21 reported the recostruction of the ipsilateral TMJ and mandibular advancement with a patient-fitted total joint prosthesis in combination with controlateral bilateral sagittal split osteotomy and maxillary osteotomies, to limit the correction to 1 major operation, in adult patients with HFM types 2b to 3. Nevertheless, we feel that, in young patients with normal mandibular function, as in our sample, this procedure should not be considered because of the unknown service life of total TMJ prosthesis. For all these abovementioned reasons, we were encouraged to develop our treatment strategy based on 2 major surgical stages with 2 different techniques. In the first stage, we aimed to restore a normal skeletal pattern in the frontal plane correcting the posterior height of the ramus condyle unit with osteodistraction of the ascending ramus. Distraction osteogenesis is supposed to overcome the tension in pterygomasseteric sling, potentially reducing the overload on the affected joint in comparison with conventional orthognatic surgery. In the second surgical stage, we opted to conventional orthognatic osteotomies to achieve definitive three-dimensional dentoskeletal relationship correction and skeletal expansion to improve facial aesthetics. Bite blocks and occlusal splint were fundamental to achieve a good consolidation of the distracted bone before proceeding with leveling of the maxilla. Figures 4 to 9 show clinical, occlusal, and radiologic records of patients 1 and 4 before surgery, after distraction osteogenesis, and after conventional osteotomies. Postdistraction (Tx, measurements not included in this study) PA and L cephalograms, three-dimensional facial surface data, and clinical examination showed an increase in height of the ascending ramus on the affected side and an improvement of the chin position in the frontal view. Instead, lips posture and chin position in profile were still inadequate. This supports the design of a multistage treatment protocol. Orthognatic surgery planning was adequate to correct these remaining morphofunctional defects.
Unilateral Mandibular Hypoplasia
Therefore, during the second major stage of the treatment protocol, our patients underwent combined maxillomandibular osteotomies. Osteotomies realized in a well-consolidated bone (at least 1 year after the completion of the distraction) are easier and present the same issue in planning, surgical technique, and stability of the conventional orthognathic osteotomies. Preoperative (T0) and long-term (T1) PA and L cephalograms and three-dimensional facial surface data were studied to objectively assess hard and soft tissue changes after completion of the standardized protocol. In L cephalograms, an increase in posterior facial height and ramus position and a normalization of overjet and overbite were observed. These effects were likely due to the mandibular vertical lengthening on the deficient side and to sagittal maxillomandibular repositioning. Comparing the PA measurements between T0 and T1, normalization of maxillomandibular dental midline alignment and occlusal plane tilt and a great improvement of L deviation of the chin were observed. These effects may be attributed to the surgical maxillomandibular complex roll, which restores mouth and chin skeletal symmetry.45 To evaluate the efficacy of treatment on the soft tissue symmetry, a presurgical face and a postsurgical face were obtained for each patient and compared with a virtual optimal face (F for patients 1 and 2 and M for patients 3 and 4). The comparison of measurements of the cutaneous landmark distances on T0 and T1 revealed no modification in the upper region of the face and that the major postsurgical changes were in the lower face.45 In the frontal view, an improvement of symmetry of the nasal base and an important correction of the lips, both vertically and horizontally, were observed. Increased support of the lips and increase in the nasal base were also shown. Although a significant normalization of soft tissue profiles was generally observed, residual defects were documented in the postoperative symmetry of the chin, as evidenced by other authors.46 The comparison of cephalometric skeletal measurements and scanner soft tissue data evidenced incomplete cutaneous symmetry achievement despite acceptable bone repositioning. All the patients expressed high levels of satisfaction with the aesthetic outcomes. This was probably due to the favorable final facial appearance achieved with the conventional osteotomies. In 3 of the 4 patients, the maxillomandibular complex was advanced leading to an increased soft tissue support due to skeletal expansion.47 The weaknesses of this protocol were the required number of surgical procedures and the total length of the treatment (mean, 32 mo; range, 24–40 mo). The small sample and the differences in length of follow-up (mean, 36 mo; range, 24–49 mo) were the main limitations of the study. More experience and further long-term follow-up studies are needed to evaluate a much larger patient population with better control over the variables.
REFERENCES 1. Pruzansky S. Not all dwarfed mandibles are alike. Birth Defects 1969;5:120–129 2. Murray JE, Kaban LB, Mulliken JB. Analysis and treatment of hemifacial microsomia. Plast Reconstr Surg 1984;74:186–199 3. Kaban LB, Moses MH, Mulliken JB. Surgical correction of hemifacial microsomia in the growing child. Plast Reconstr Surg 1988;82:9–19 4. Obwegeser HL. Mandibular growth anomalies. Terminology, aetiology, diagnosis, treatment. New York: Springer-Verlag Berlin Heidelberg, 2001:43–117 5. Meazzini MC, Brusati R, Caprioglio A, et al. True hemifacial microsomia and hemimandibular hypoplasia with condylar-coronoid collapse: diagnostic and prognostic differences. Am J Orthod Dentofacial Orthop 2011;139:e435–e447
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Copyright © 2014 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
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6. Cheong YW, Lo LJ. Facial asymmetry: etiology, evaluation and management. Chang Gung Med J 2011;34:341–351 7. Poswillo D. Experimental reconstruction of the mandibular joint. Int J Oral Surg 1974;3:400–411 8. Taylor GI. Reconstruction of the mandible with free composite iliac bone graft. Ann Plast Surg 1982;9:361–376 9. Guelnick PJ, Sinsel NK. The “Eve” procedure: the transfer of vascularized seventh rib, fascia, cartilage and serratus muscle to reconstruct different defects. Plast Reconstr Surg 1996;97:527–535 10. Samman N, Cheung LK, Tideman H. Variations in costochondral grafting of the mandibular ramus. Ann R Australas Coll Dent Surg 1996;13:144–153 11. Padwa BL, Mulliken JB, Maghen A, et al. Midfacial growth after costochondral graft construction of the mandibular ramus in hemifacial microsomia. J Oral Maxillofac Surg 1998;56:122–127 12. Wax MK, Winslow CP, Hansen J, et al. A retrospective analysis of temporomandibular joint reconstruction with free fibula microvascular flap. Laryngoscope 2000;110:977–981 13. Ortiz-Monasterio F. Early mandibular and maxillary osteotomies for the correction of hemifacial microsomia: a preliminary report. Clin Plast Surg 1982;9:509–517 14. Zanardi G, Parente EV, Esteves LS, et al. Orthodontic and surgical treatment of a patient with hemifacial microsomia. Am J Orthod Dentofacial Orthop 2012;141:S130–S139 15. Mc Carthy JG, Schreiber J, Karp N, et al. Lengthening of the human mandible by gradual distraction. Plast Reconstr Surg 1992;89:1–10 16. Molina F, Ortiz Monasterio F. Mandibular elongation and remodeling by distraction: a farewell to major osteotomies. Plast Reconstr Surg 1995;96:825–842 17. Kaban LB, Padwa BL, Mulliken JB. Surgical correction of mandibular hypoplasia in hemifacial microsomia: the case for treatment in early childhood. J Oral Maxillofac Surg 1998;56:628–638 18. McCarthy JG, Staffenberg DA, Wood RJ, et al. Introduction of an intraoral bone-lengthening device. Plast Reconstr Surg 1995;96:978–981 19. Diner PA, Kollan EM, Martinez H, et al. Intraoral distraction for mandibular lengthening: a technical innovation. J Craniomaxillofac Surg 1996;24:92–95 20. Mercuri LG, Swift JQ. Considerations for the use of alloplastic temporomandibular joint replacement in the growing patient. J Oral Maxillofac Surg 2009;67:1979–1990 21. Wolford LM, Bourland C, Rodrigues D, et al. Successful reconstruction of nongrowing hemifacial microsomia patients with unilateral temporomandibular joint total joint prosthesis and orthognathic surgery. J Oral Maxillofac Surg 2012;70:2835–2853 22. Ramieri GA, Spada MC, Nasi A, et al. Reconstruction of facial morphology from laser scanned data. Part I: reliability of the technique. Dentomaxillofac Radiol 2006;35:158–164 23. Yamauchi K, Takahashi T. Maxillary distraction osteogenesis combined with mandibular osteotomy to correct asymmetry of the maxillomandibular complex. Plast Reconstr Surg 2006;118:39e–45e 24. Kofod T, Norholt SE, Pedersen TK, et al. Reliability of distraction vector transfer in unilateral vertical distraction of the mandibular ramus. J Craniofac Surg 2005;16:15–22 25. Proffit WR, Turvey TA, Phillips C. Orthognathic surgery: a hierarchy of stability. Int J Adult Orthodon Orthognath Surg 1996;11:191–204 26. Whitaker LA, Munro IR, Salyer KE, et al. Combined report of problems and complications in 793 craniofacial operations. Plast Reconstr Surg 1979;64:198–203
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27. James DR, Irvine GH. Autogenous rib grafts in maxillofacial surgery. J Maxillofac Surg 1983;11:201–203 28. Ilizarov GA. The principles of the Ilizarov method. Bull Hosp Jt Dis Orthop Inst 1988;48:1–11 29. Rachmiel A, Levy M, Laufer D. Lengthening of the mandible by distraction osteogenesis: report of cases. J Oral Maxillofac Surg 1995;53:838–846 30. Ortiz-Monasterio F, Molina F, Andrade L, et al. Simultaneous mandibular and maxillary distraction in hemifacial microsomia in adults: avoiding occlusal disasters. Plast Reconstr Surg 1997; 100:852–861 31. Grayson BH, Santiago PE. Distraction osteogenesis. Semin Orthod 1999;5:1–73 32. McCarthy JG. The role of distraction osteogenesis in the reconstruction of the mandible in unilateral craniofacial microsomia. Clin Plast Surg 1994;21:625–631 33. Swennen G, Schliephake H, Dempf R, et al. Craniofacial distraction osteogenesis: a review of the literature: part 1. Clinical studies. Int J Oral Maxillofac Surg 2001;30:89–103 34. Mommaerts M, Nagy K. Is early osteodistraction a solution for the ascending ramus compartment in hemifacial microsomia? A literature study. J Craniomaxillofac Surg 2002;30:201–207 35. Venditelli BL, Dec W, Warren SM, et al. The importance of vector selection in preoperative planning of bilateral mandibular distraction. Plast Reconstr Surg 2008;122:1144–1153 36. Mulliken JB, Kaban LB. Analysis and treatment of hemifacial microsomia in childhood. Clin Plast Surg 1987;14:91–100 37. Hollier LH, Kim JH, Grayson B, et al. Mandibular growth after distraction in patients under 48 months of age. Plast Reconstr Surg 1999;103:1361–1370 38. Huisinga-Fischer CE, Vaandrager JM, Prahl-Andersen B. Longitudinal results of mandibular distraction osteogenesis in hemifacial microsomia. J Craniofac Surg 2003;14:924–933 39. Meazzini MC, Mazzoleni F, Canzi G, et al. Mandibular distraction osteogenesis in hemifacial microsomia: long-term follow-up. J Craniomaxillofac Surg 2005;33:370–376 40. Padwa BL, Kearns GJ, Todd R, et al. Simultaneous maxillary and mandibular distraction osteogenesis with a semiburied device. Int J Oral Maxillofac Surg 1999;28:2–8 41. Cho BC, Shin DP, Park JW, et al. Bimaxillary osteodistraction for treatment of facial asymmetry in adults. Br J Plast Surg 2001;54:491–498 42. Matsumoto K, Nakanishi H, Koizumi Y, et al. Occlusal difficulties after simultaneous mandibular and maxillary distraction in an adult case of hemifacial microsomia. J Craniofac Surg 2004;15:464–468 43. Shehata EAA, Medra AMM. Modified bimaxillary distraction osteogenesis: a technique to correct facial asymmetry. Br J Oral Maxillofac Surg 2007;45:471–477 44. Scolozzi P, Herzog G, Jaques B. Simultaneous maxillo-mandibular distraction osteogenesis in hemifacial microsomia: a new technique using two distractors. Plast Reconstr Surg 2006;117:1530–1542 45. Verzè L, Bianchi FA, Schellino E, et al. Soft tissue changes after orthodontic-surgical correction of jaws asymmetry evaluated by 3D surface laser scanner. J Craniofac Surg 2012;23:1448–1452 46. Ko EW, Huang CS, Chen YR. Characteristics and corrective outcome of face asymmetry by orthognathic surgery. J Oral Maxillofac Surg 2009;67:2201–2209 47. Rosen HM. Facial skeletal expansion: treatment strategies and rationale. Plast Reconstr Surg 1992;89:798–808
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Copyright © 2014 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
Unilateral Mandibular Hypoplasia in Adult Patients: Distraction Osteogenesis and Conventional Osteotomies in a Standardized Sequence Giovanni Gerbino, MD, DDS,* Francesca Antonella Bianchi, MD,* Laura Verzé, MD,† and Guglielmo Ramieri, MD, DDS* Introduction: This study analyzed the outcomes of nongrowing patients with unilateral mandibular hypoplasia treated according to a specific protocol, which combines distraction osteogenesis, orthodontic treatment, and conventional osteotomies. Materials and Methods: The patients treated were objectively evaluated. Patient’s satisfaction was assessed by questionnaire. Surgical changes were analyzed using cephalometry and three-dimensional facial surface data before surgery (T0) and at long-term (T1) follow-up. Results: Four patients were included in this study. The normalization of facial proportion and a high increase in symmetry were evident. Residual defects were documented in the postoperative symmetry of the chin. In the questionnaire, all patients gave favorable responses to their facial changes; for most of the objective parameters, all patients improved. Conclusions: A multistage treatment protocol for the correction of facial deformities in patients with unilateral mandibular hypoplasia is a valid procedure for skeletal and occlusal stability. An evident improvement of the facial appearance is also achieved. Key Words: Unilateral mandibular hypoplasia, facial asymmetry, osteogenesis, conventional orthognathic surgery, three-dimensional surface laser scanner
resulting in facial deviation with a combination of a retrognathic mandible deviated toward the ipsilateral side with chin point deviation, canting of the occlusal plane with hypoplasia of the ipsilateral maxilla, gonion, and lips asymmetry. These clinical features can be found both in patients with lack of neural crest cells migration, such as hemifacial microsomia (HFM) types 2a to 2b,1–3 and in patients with growth abnormalities due to trauma, infections, or surgical iatrogenic deformities, which occurred in the condylar region during late fetal or postnatal development.4,5 Restoration of facial symmetry, in adult patients with UMH, regardless of the etiology (ie, congenital, developmental, or acquired) continues to be a challenging procedure for craniofacial surgeons.6 Autogenous bone grafts,7–12 conventional orthognathic surgery,13,14 distraction osteogenesis,15–19 and temporomandibular joint (TMJ) prostheses20,21 have been proposed as surgical solutions for the correction of a curvilinear facial profile. The purpose of this prospective study was to evaluate the outcomes of nongrowing patients with UMH treated according to a specific protocol, which combines, in a standardized sequence, distraction osteogenesis, orthodontic treatment, and conventional maxillomandibular osteotomies. The specific aim of the study was to assess the amount of correction achieved by cephalometric analysis, three-dimensional analysis of the soft tissue changes, and clinical evaluation.
MATERIALS AND METHODS
(J Craniofac Surg 2014;25: 1959–1966)
U
nilateral mandibular hypoplasia (UMH) is characterized by asymmetric underdevelopment of the mandibular condyle and ramus What Is This Box? A QR Code is a matrix barcode readable by QR scanners, mobile phones with cameras, and smartphones. The QR Code links to the online version of the article.
From the *Division of Maxillofacial Surgery, Surgical Sciences Department, San Giovanni Battista Hospital, and †Department of Science of Public Health and Pediatrics, University of Turin, Turin, Italy. Received July 28, 2013. Accepted for publication March 13, 2014. Address correspondence and reprint requests to Francesca Antonella Bianchi, MD, Division of Maxillofacial Surgery, Surgical Sciences Department, San Giovanni Battista Hospital, University of Turin, Corso A.M. Dogliotti 14, 10126 Torino, Italy; E-mail: [email protected] The manuscript is not under consideration by another journal, nor has it been previously published. The authors report no conflicts of interest. Copyright © 2014 by Mutaz B. Habal, MD ISSN: 1049-2275 DOI: 10.1097/SCS.0000000000000975
From January 2004 to June 2010, 6 patients with UMH received a specific treatment protocol, which combined distraction osteogenesis, orthodontic treatment, and conventional orthognathic surgery at the Division of Maxillofacial Surgery, San Giovanni Battista Hospital, University of Turin, Turin, Italy. All patients had the following features: (1) hypoplasia of the mandibular condyle and ramus, (2) retrognathic mandible deviated toward the ipsilateral side, (3) canting of the occlusal plane and lips, and (4) hyperdivergent facial morphology (Fig. 1). Inclusion criteria were nongrowing patients with UMH and complete records before surgery (T0), after each phase of surgical protocol (Tx), and at the longest follow-up (T1). Exclusion criteria were evidence of continued growth; hystory of craniofacial injury or craniofacial syndrome; and incomplete clinical and radiologic records at T0, Tx, and T1. Thus, 4 white adult subjects with UMH were enrolled in the study. Patients presented UMH with right (1 patient) or left (3 patients) lateral (L) deviation. Sagittal and vertical jaws’ discrepancies and malocclusion are described in Tables 1 and 2. The treatment protocol consisted of (1) intraoral distraction of the ascending ramus with the support of individual prefabricated occlusal splint and guiding elastics, (2) postdistraction orthodontic treatment to prepare for conventional osteotomies, (3) conventional orthognathic surgery (combined Le Fort I osteotomy, bilateral sagittal split osteotomy) at least 1 year after completion of the distraction period, and (4) postsurgical orthodontic treatment.
The Journal of Craniofacial Surgery • Volume 25, Number 6, November 2014
Copyright © 2014 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
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Surgical Procedures Three-dimensional multislices computerized tomography scans were used for planning the distraction phase. In the first 2 cases, stereolithographic models were used for the simulation of distraction vector and the resulting mandibular repositioning. Under general anesthesia, a unidirectional distraction device was positioned, through an intraoral approach, on the L face of the ascending ramus, with screws placed through a transbuccal trocar. The distraction vector was vertical to achieve elongation of the ascending ramus, that is, the major axis of the distractor was parallel or with an angle inferior to 45 degrees to the posterior border of the ascending ramus. The planned osteotomy line was perpendicular to the distraction vector. After a corticotomy of the posterior border, lateral cortex, and anterior border, complete fracture of the ascending ramus was performed, leaving the neurovascular bundle intact and the lingual periosteum attached. The internal distraction device was fit in place, fixed, and activated to ensure free movement of the bone segment. The wound was closed in layers. All patients were treated with oral antibiotics for 6 postoperative days. Distraction was begun after a latency period of 6 days; performed at a rate 0.4 mm, 2 times daily; and continued until the planned position, including overcorrection, was achieved. During the activation phase, an individual prefabricated occlusal splint was used to support the development of an ipsilateral open bite. Guiding elastics were used to avoid a midline shift to the controlateral side. At the weekly control visits during the active distraction phase, the stabilization splint was corrected. During the distraction phase, radiographic and clinical examinations were done at follow-up visits. The consolidation period was 9 weeks (range, 6–12 w), after which the distraction devices were removed under general anesthesia. During the consolidation phase, the supporting occlusal splint with bite blocks was used to mantain the unilateral open bite. A conventional postdistraction presurgical fixed orthodontic treatment was started. Treatment objectives were leveling and alignment of the maxilla and elimination of dental compensations with coincidence of the dental midline with the bony mandibular midline. At least 1 year after completion of the distraction period and after an adequate orthodontic preparation, conventional orthognathic surgery was performed to adjust three-dimensional residual dentoskeletal discrepancies. In all patients, combined Le Fort I osteotomy, bilateral sagittal split osteotomy, and additional procedures (genioplasty and/or rhinoplasty) were required to correct any maxillary and mandibular
FIGURE 1. Patient 2. A and B, A 17-year-old female adolescent had the clinical features of the right-side UMH (facial asymmetry, retrognathic mandible deviated toward the ipsilateral side with chin point deviation, canting of the occlusal plane, gonion, and lips asymmetry). C and D, Three-dimensional and coronal computerized tomography scans showing asymmetric underdevelopment of the right mandibular condyle and ramus.
Additional procedures (genioplasty and/or rhinoplasty) were performed at the same surgical time of conventional maxillomandibular osteotomies or delayed (6 months later) (Table 1). Posteroanterior (PA) and L cephalometry and three-dimensional facial surface data were obtained before distraction (T0) and at the longest follow-up (T1). Clinical evaluation was performed at T0 and T1, and patients’ satisfaction with facial appearance after surgery was subjectively evaluated by a questionnaire. Informed consent was obtained from all participants. This study was performed in agreement with a local institutional review board. We followed the Helsinki Declaration guidelines.
TABLE 1. Patient’s Pathology Description and Problems Concerning Their Occlusion and Surgical Treatment Pathology Etiology of facial Patients Sex Age, Y asymmetry
Mandible L Direction of Maxilla Inclination of Anterior Posterior Trasversal Vertical problems palatal Deviation (mm) mandible L superior the occlusal crossbite crossbite defect plane deviation rotation
1
F
18
Congenital: HFM 2a
11
2
F
17
7
3
M
19
4
M
17
Acquired: neonatal arthritis Acquired: neonatal arthritis Acquired: neonatal arthritis
11
6
Left (left mandibular hypoplasia) Right (right mandibular hypoplasia) Left (left mandibular hypoplasia) Left (left mandibular hypoplasia)
Yes
Yes
-
-
-
-
Yes
Yes
-
-
-
Yes
Yes
-
Yes
Yes
Yes
-
-
Surgery
Follow-Up (T1), Mo
Left MD, C, G + RSP
32
Deep bite
Right MD, C+G
24
Yes
-
Left MD, C+G
49
-
Deep bite
Left MD, C + G + RSP
40
Hyphen (-) indicates absence of some defects. MD, mandible distraction; C, combined maxilla-mandible surgery; RSP, rhinoplasty; G, genioplasty.
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© 2014 Mutaz B. Habal, MD
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Unilateral Mandibular Hypoplasia
TABLE 2. Measurements of L and PA Cephalograms Patient 1
L Cephalometry
PA Cephalometry
Posterior facial height (Go-CF), mm Ramus position, degrees Maxillary depth (FH-NA)N, degrees Facial angle (FH-Npo), degrees Facial axis-Ricketts (NaBa-PtGn), degrees Convexity (A-Npo), mm U-incisor protusion (U1-Apo), mm U1-FH, degrees U-incisor inclination (U1-Apo), degrees L1 protrusion (L1-Apo), mm L1 to A-Po, degrees Mandibular incisor extrusion, mm Overjet, mm Overbite, mm Dental midline discrepancy, mm Maxillomandibular midline, mm Occlusal plane tilt, degrees Postural symmetry, degrees Maxillary width, mm Mandibular width, mm Facial width, mm A-Me-MSR, degrees
Patient 2
Patient 3
Patient 4
Normal Values*
T0
T1
T0
T1
T0
T1
T0
T1
60.1 (3.3) 76 (3) 90 (3) 88.6 (3) 90 (3.5) 0.7 (2) 3.5 (2.3) 111 (6) 28 (4) 1 (2.3) 22 (4) 1.2 (2) 2.5 (2.5) 2.5 (2) 0 (1.5) 0 (2) 0 (2) 0 (2)
48.8 61.9 81.5 76.2 78.4 5 8 100.3 29.6 3.1 26.6 1.6 4.5 3.1 −0.1 12.6 −8.7 −0.4 64 83 118.9 11
62.2 75.1 92.3 85.2 82 7.6 10.9 108.6 30.9 4.9 26.3 −0.2 3 0.5 −0.6 5.9 0 −1.4 60.1 89 117.8 2
53.6 70.9 92.1 84 79.6 7.7 9.3 103.2 27.5 3.9 26.4 2.6 5 5.2 1.8 −6.2 8.6 2.6 61.1 83.7 117.5 7
64.1 83 94.7 87.6 83.9 7.1 8.9 114.3 34.9 6.6 33.2 1.6 2 3 −0.6 0.5 0 −1.2 52.3 77.4 98.9 0.5
62.4 61.9 79.2 70.8 77.5 10 17.3 112 51.5 −1.8 13.4 3.6 10 3 0.8 10.8 −3.8 −6.6 57.3 92.9 118.6 11
74.3 69.5 78 70.8 79.9 8.5 7.3 88.6 26.7 1.7 24.4 0.9 5 2 −0.2 −1.4 0 −4.2 62.8 92.3 119.8 2
59.8 54.3 73.3 68.4 78.7 5.5 10.2 86.5 23.5 7.3 27.3 1.3 3 4.6 0.7 6 −8.7 −1.5 75.5 102.3 144.2 6
75.6 61.6 79.4 73.7 80.2 6.8 4.7 87.1 20 2.4 34.7 0.1 2 2 −0.4 3.1 0 1.8 70.5 104.2 141.4 3
0 (2)
*Values are mean (SD).
deformities and to achieve better symmetry. Postsurgical orthodontic treatment was essential for all patients to attain optimal results.
30.000 points. Facial surface reconstruction, multiple scan alignment, and measurements were carried out using Rapid Form 2004 software (INUS Technologies Inc, Seoul, South Korea).
Cephalometric Measurements The PA and L cephalograms were traced by 1 examiner using the software Dolphin 11.0 Premium (Dolphin Imaging, Chatsworth, CA). The following measurements were obtained to assess sagittal, vertical, and transversal skeletal and dental movements: posterior facial height (Go-CF), ramus position, maxillary depth (FH-NA) N, facial angle (FH-NPo), facial axis-Ricketts (NaBa-PtGn), convexity (A-NPo), U-incisor protusion (U1-APo), U1-FH, U-incisor inclination (U1-APo), L1 protrusion (L1-APo), L1 to A-Po, mandibular incisor extrusion, overjet, overbite, dental midline discrepancy, maxillomandibular midline, occlusal plane tilt, postural symmetry, maxillary width, mandibular width, facial width, and A-Me-MSR (Table 2). A subsample of 8 randomly selected radiographs were retraced and digitized 1 month later to calculate the systematic errors. All the angular and linear measurements were compared between the 2 time sets by paired t-test. All the measurements presented no significant difference at retracing.
Facial Scan and Data Processing Facial surface data were acquired using a Head and Face Color 3D Scanner (3030RGB; Cyberware, Inc, Monterey, CA). All subjects were registered with the head in natural position, the eyes closed, and the teeth in occlusion. The scanning method took into consideration previous observations concerning the positioning of the subject and environmental conditions. The detailed protocol to reduce the artifacts was previously described.22 The acquired data were transferred to a graphics workstation for viewing and elaboration with Cyberware Echo software (Cyberware Inc, Monterey, CA). Scanned data sets were first restricted to the facial area and then reduced from around 160.000 to
FIGURE 2. Top, Virtual optimal female face F. Bottom, Virtual optimal male face M. A and C, Frontal views with horizontal and vertical reference planes. B and D, Profile views.
© 2014 Mutaz B. Habal, MD
Copyright © 2014 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
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TABLE 3. Point-to-Point Distances of the Landmarks Considered Patient 1 Distances Symmetry
Vertical
Transversal
Angles
enr–alr enl–all enr–chr enl–chl alr–chr all–chl sn–chr sn–chl alr–x all–x chr–x chl–x sn–ls li–pg sn–pg pg–x chr–sn–chl chr–pg–chl alr–y all–y chr–y chl–y pg–y Nasolabial angle Labial-mental angle
Patient 2
Patient 3
Patient 4
F
T0
T1
T0
T1
M
T0
T1
T0
T1
36.33 36.93 62.98 63.05 31.35 31.50 37.82 37.71 36.35 36.05 61.27 61.21 13.78 22.69 50.03 89.24 85.68 81.24 14.25 14.98 25.66 26.02 0 132.83 143.55
36.48 37.28 63.80 59.57 35.02 26.63 35.52 33.52 32.66 30.93 62.95 57.25 15.77 20.15 50.07 86.26 80.78 76.69 13.80 15.55 19.53 26.86 12.18 136.76 126.76
35.64 36.66 64.91 64.92 30.72 31.18 37.36 36.60 35.77 35.60 64.98 64.34 17.17 18.97 52.47 90.14 84.36 78.64 16.87 16.95 24.54 23.53 2.76 138.38 136.11
37.64 40.93 60.64 65.49 25.41 30.75 35.15 37.21 32.49 35.58 59.03 61.52 15.68 21.81 55.39 88.66 77.68 69.02 18.24 13.57 27.81 21.49 4.42 159.49 124.48
41.27 40.26 66.58 65.56 30.11 28.57 37.95 38.58 36.69 36.50 64.85 64.50 14.33 25.36 54.92 91.16 86.17 77.96 17.03 17.15 25.18 26.01 1.10 138.66 140.64
38.17 38.90 68.98 69.09 33.31 33.28 40.81 40.96 38.16 38.54 68.30 68.42 15.69 22.38 54.80 98.84 86.31 83.87 18.37 17.92 26.73 26.91 0 134.57 139.06
40.98 44.39 70.89 68.93 32.80 31.70 38.66 37.99 38.40 36.80 69.25 65.19 17.17 22.17 53.06 93.41 78.40 77.99 16.79 23.01 18.31 30.04 11.88 137.45 109.40
39.44 40.17 72.44 72.10 34.36 34.19 40.62 39.70 37.76 37.05 69.09 68.11 19.02 23.47 57.30 99.76 87.51 85.22 17.94 18.51 26.36 27.01 3.21 127.35 118.26
39.96 39.11 69.60 65.75 30.85 29.79 39.09 37.36 35.22 32.24 65.98 60.71 14.91 22.10 52.55 88.83 81.81 78.63 18.04 20.13 19.10 29.25 9.10 143.91 116.56
42.72 42.46 71.26 70.74 33.27 33.19 41.16 40.41 37.01 36.62 69.02 68.10 16.86 22.42 54.98 98.36 84.89 83.47 19.38 20.04 27.20 27.25 4.30 139.73 122.45
Values are in millimeters. F, virtual optimal female face; M, virtual optimal male face.
A virtual optimal male face M was constructed by averaging the scans of 40 healthy adult men, and a virtual optimal female face F was constructed by averaging the scans of 40 healthy adult women (Fig. 2).T0-T1, T0-F (for patients n = 1–2), T0-M (for patients n = 3–4), T1-F (for patients n = 1–2), and T1-M (for patients n = 3–4) were registered on homologous points. Reference vertical (midline through the glabella) and horizontal (through the right and left endocanthion) planes were constructed on the models (Fig. 2). Different linear and angular measurements were calculated for comparison of the T0 and T1 models using 10 landmarks taken from classic anthropometry. The landmarks were enr, right endocanthion; enl, left endocantion; alr, right alar crest point; all, leflt alar crest point; sn, subnasale; chr, righ cheilion; chl, left cheilion; ls, labialis superior; li, labialis inferior; and pg, pogonion (Table 3).
Clinical Evaluation and Patients’ Satisfaction At T0 and T1, all patients underwent a standardized evaluation consisted of aesthetic evaluation (facial symmetry, maxillomandibular chin position, lips posture, etc) and dental-periodontal assessment (clinical evaluation, periodontal probing, thermal test). At T0 and T1, each patient was asked to compare the photographs of their own face with the virtual optimal face F (patients 1 and 2) or M (patients 3 and 4) and then to complete a questionnaire to subjectively assess the perceptions of their facial appearance. The patients were invited to evaluate the following 5 parameters: (1) facial symmetry, (2) gonion symmetry, (3) chin position in frontal view, (4) chin position in profile, and (5) lips posture. All items were evaluated on numerical rating scales ranging from 1 to 10 (with 10 indicating the best imaginable appearance). The total patient score is obtained by adding the scores of each of the 5 items (range, 5–50), with higher
TABLE 4. Results of Surgical Treatment Pathology Patients 1 2 3 4
Mandible L Deviation, mm
Maxilla Superior Rotation
Inclination of the Occlusal Plane
Anterior Crossbite
Posterior Crossbite
Trasversal Palatal Defect
5* 0.5* 2* 3*
Yes
-
-
-
-
Vertical Problems Slight deep -
Absence (-) or persistence of some defects (*).
1962
© 2014 Mutaz B. Habal, MD
Copyright © 2014 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
The Journal of Craniofacial Surgery • Volume 25, Number 6, November 2014
FIGURE 3. Facial surface reconstruction of all 4 patients, at T0 and T1. Morphologic changes between T0 and T1 were investigated grossly as shell-to-shell deviation. The areas with major movement were represented in red; little movement, in green; and no movement, in blue. This provided information on local changes, as a false-color map (clearance vector map).
scores indicating the best imaginable facial appearance. The patients finally gave an overall opinion on their own facial appearance, with a score ranging from 1 to 10.
RESULTS Four patients, 2 women and 2 men, fullfilled inclusion criteria for the study. All patients were white adult subjects (mean age, 17.7 y; range, 17–19 y) with UMH. The mean follow-up duration was 36 months (range, 24–49 mo) (Table 1).
Cephalometric Measurements Cephalometric changes and clinical outcomes are summarized in Tables 2 and 4. The L measurements showed an increase in the posterior facial height and in ramus position and an improvement of the overjet and overbite. All patients had high values of convexity both at T0 and T1 (Table 2). The PA measurements revealed a normalization of the occlusal plane tilt and an improvement of maxillomandibular midline alignment and of the A-Me-MSR values (Table 2).
Unilateral Mandibular Hypoplasia
FIGURE 4. Patient 1. Left to right, Full face front view, front view with smile, and profile view. A–C, An 18-year-old woman had left-side UHM. D–F, Clinical views after unilateral mandibular distraction. G–I, The patient was seen at T1, after conventional orthognathic surgery and ancillary procedures (rhinoplasty and genioplasty).
Facial Scan and Data Processing The comparison of facial surface at T0 and T1 showed an overall increase in symmetry for all patients. Normalizations of the vertical and transversal positions of the labial commissures and of the nasal alae were evident. Increase in the sagittal projection of the lips and of the chin was also noticed. Reduced but still noticeable deviation of the chin on the symmetry axis (Y) was observed (Fig. 3). Measurements at T0 and T1 documented that the major postsurgical changes were in the lower area of the face (Table 3). After treatment, the distances of the lips from en (en-ch) were increased, and the distances of the lips from the columella (sn-ch) were normalized; a symmetrization between the 2 sides (right and left) was also evident. At T0, the al and ch points of the 2 sides demonstrated both vertical and horizontal asymmetries, particularly noticeable concerning the lips’ position. Symmetry of these measurements was significantly improved at T1 (Table 3).
TABLE 5. Subjective Evaluations Chin Facial Gonion Chin Position Position Symmetry Symmetry in Frontal View in Profile T0
T1
T0
T1
T0
T1
2.1 Range 1–4
7.2 6–8
1.9 1–3
6.8 5–8
2.8 1–5
8.2 6–10
Mean
T0
T1
Lips Posture T0
T1
Overall Opinion T0
T1
1.4 8.9 2.6 9.4 2.4 9.1 1–3 7–10 2–5 8–10 1–5 8–10
FIGURE 5. Patient 1. A, Occlusion before treatment. B, After distraction osteogenesis, bite blocks and occlusal splint were fundamental to achieve a good consolidation of the distracted bone before proceeding with leveling of the maxilla and with the latest surgical step. C, Occlusion at 32 months after treatment (T1).
© 2014 Mutaz B. Habal, MD
Copyright © 2014 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
1963
Gerbino et al
The Journal of Craniofacial Surgery • Volume 25, Number 6, November 2014
FIGURE 8. Patient 4. A, Occlusion before treatment. B, After distraction osteogenesis, bite blocks and occlusal splint were used before proceeding with the latest surgical step. C, Occlusion at 40 months after treatment (T1).
Clinical Evaluation and Patients’ Satisfaction
FIGURE 6. Patient 1. Left to right, PA cephalogram (top) and L cephalogram (bottom) before surgery (A and D), at the end of the distraction phase (B and E), and immediately after conventional osteotomies (C and F).
The long-term aesthetic result was satisfactory in all 4 patients. In particular, the positions of the labial commissures and the nasal alae were correct, and a great improvement of facial symmetry was evident. No tooth mobility, gingival bleeding, and nonvital teeth were noted. Two patients had evidence of varying degrees of gingival recession and radicular resorption. The results provided by patient score showed a substantial increase (from T0 to T1) of the scores of almost all of the items. In particular, all patients gave favorable scores to their postoperative chin position in profile, lips posture, and overall facial symmetry. Subjective evaluation results are reported in Table 5.
DISCUSSION Increased sustaining of the lips was also evident, without a visible enlargement of the intercommissural distance (chr-chl); instead, a slight nasal base flaring was observable (Table 3).
FIGURE 7. Patient 4. Left to right, Full face front view, front view with smile, and profile view. A–C, A 17-year-old male adolescent had left-side UHM. D–F, Clinical views after unilateral mandibular distraction. G–I, The patient was seen at T1, after conventional orthognathic surgery and ancillary procedures (rhinoplasty and genioplasty).
1964
An adverse event to the condylar region during late postfetal or early postnatal growth can result in abnormal growth and malformation of the mandible with UMH and facial deviation as a combination of tilted occlusal plane, chin point deviation, curved facial midline, gonion, and/or lips asymmetry. The mandibular shape in this group of patients is very similar to each other depending mainly on degree of the damage and the developmental stage of the mandible and seems almost independent of the type of the adverse event.4 The clinical skeletal features are very similar either to HFM 2a to 2b or pseudo-HFM. For this reason, we included in our study 3 patients who had condilar damage after neonatal infection arthritis and 1 patient with HFM 2a. All patients included in our study were referred to our institution after completion of the growth, and the protocol applied was designed for this kind of patients. Many options have been proposed for the surgical correction of HFM or pseudo-HMF. Conventional orthognathic surgery causes a high risk of relapse because of the large amount of movement23,24; furthermore, the pterygomasseteric sling prevents the successful mandibular vertical ramus lengthening and leads to unpleasant results.24,25
FIGURE 9. Patient 4. Left to right, PA cephalogram (top) and L cephalogram (bottom) before surgery (A and D), at the end of the distraction phase (B and E), and immediately after conventional osteotomies (C and F).
© 2014 Mutaz B. Habal, MD
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The Journal of Craniofacial Surgery • Volume 25, Number 6, November 2014
The results, using autogenous bone grafts to increase the volume and size of hypoplastic ascending ramus, are often unpredictable.23 Undesirable remodeling of the graft can decrease the volume and strength of the reconstructed area.23 The grafting technique requires an extraoral approach and causes morbidity at the donor site26,27; moreover, this procedure is limited in volume and is often complicated by infection when alloplastic grafts are inserted.20,23 The distraction osteogenesis, first described for orthopedic surgery,28 has become increasingly popular for the treatment of facial asymmetries during the last 2 decades.15,16,29–31 One of the most significant advantages of distraction is the gradual lengthening of both hard and surrounding soft tissue envelopes.13,16,24,32–35 In growing patients, distraction osteogenesis with proper distraction vector planning, overcorrection, bite block, and guiding elastics can reestablish mandibular symmetry and prevent either occlusal canting or the restriction of vertical maxillary growth.15,17,24,34,36 Recently, studies based on cephalometric data showed that early distraction is successful in the short-term follow-up but leads to a gradual return to the original facial proportion at the long-term follow-up, expecially in true HFM.5,34,37–39 In adults, dental occlusion can be changed drastically by distraction osteogenesis and unacceptably prolonged, and difficult orthodontic treatment is required to achieve a satisfactory result.30,40–43 Scolozzi et al44 proposed the use of 2 independent distractors for a simultaneous maxillomandibular distraction osteogenesis without the use of intermaxillary fixation in the restorative treatment of HFM in adults, to avoid occlusal problems. Because our patients presented a retrognathic mandible, they would not have obtained a satisfactory correction of all the aesthetic defects by resorting to combined maxillomandibular distraction. Recently, Wolford et al21 reported the recostruction of the ipsilateral TMJ and mandibular advancement with a patient-fitted total joint prosthesis in combination with controlateral bilateral sagittal split osteotomy and maxillary osteotomies, to limit the correction to 1 major operation, in adult patients with HFM types 2b to 3. Nevertheless, we feel that, in young patients with normal mandibular function, as in our sample, this procedure should not be considered because of the unknown service life of total TMJ prosthesis. For all these abovementioned reasons, we were encouraged to develop our treatment strategy based on 2 major surgical stages with 2 different techniques. In the first stage, we aimed to restore a normal skeletal pattern in the frontal plane correcting the posterior height of the ramus condyle unit with osteodistraction of the ascending ramus. Distraction osteogenesis is supposed to overcome the tension in pterygomasseteric sling, potentially reducing the overload on the affected joint in comparison with conventional orthognatic surgery. In the second surgical stage, we opted to conventional orthognatic osteotomies to achieve definitive three-dimensional dentoskeletal relationship correction and skeletal expansion to improve facial aesthetics. Bite blocks and occlusal splint were fundamental to achieve a good consolidation of the distracted bone before proceeding with leveling of the maxilla. Figures 4 to 9 show clinical, occlusal, and radiologic records of patients 1 and 4 before surgery, after distraction osteogenesis, and after conventional osteotomies. Postdistraction (Tx, measurements not included in this study) PA and L cephalograms, three-dimensional facial surface data, and clinical examination showed an increase in height of the ascending ramus on the affected side and an improvement of the chin position in the frontal view. Instead, lips posture and chin position in profile were still inadequate. This supports the design of a multistage treatment protocol. Orthognatic surgery planning was adequate to correct these remaining morphofunctional defects.
Unilateral Mandibular Hypoplasia
Therefore, during the second major stage of the treatment protocol, our patients underwent combined maxillomandibular osteotomies. Osteotomies realized in a well-consolidated bone (at least 1 year after the completion of the distraction) are easier and present the same issue in planning, surgical technique, and stability of the conventional orthognathic osteotomies. Preoperative (T0) and long-term (T1) PA and L cephalograms and three-dimensional facial surface data were studied to objectively assess hard and soft tissue changes after completion of the standardized protocol. In L cephalograms, an increase in posterior facial height and ramus position and a normalization of overjet and overbite were observed. These effects were likely due to the mandibular vertical lengthening on the deficient side and to sagittal maxillomandibular repositioning. Comparing the PA measurements between T0 and T1, normalization of maxillomandibular dental midline alignment and occlusal plane tilt and a great improvement of L deviation of the chin were observed. These effects may be attributed to the surgical maxillomandibular complex roll, which restores mouth and chin skeletal symmetry.45 To evaluate the efficacy of treatment on the soft tissue symmetry, a presurgical face and a postsurgical face were obtained for each patient and compared with a virtual optimal face (F for patients 1 and 2 and M for patients 3 and 4). The comparison of measurements of the cutaneous landmark distances on T0 and T1 revealed no modification in the upper region of the face and that the major postsurgical changes were in the lower face.45 In the frontal view, an improvement of symmetry of the nasal base and an important correction of the lips, both vertically and horizontally, were observed. Increased support of the lips and increase in the nasal base were also shown. Although a significant normalization of soft tissue profiles was generally observed, residual defects were documented in the postoperative symmetry of the chin, as evidenced by other authors.46 The comparison of cephalometric skeletal measurements and scanner soft tissue data evidenced incomplete cutaneous symmetry achievement despite acceptable bone repositioning. All the patients expressed high levels of satisfaction with the aesthetic outcomes. This was probably due to the favorable final facial appearance achieved with the conventional osteotomies. In 3 of the 4 patients, the maxillomandibular complex was advanced leading to an increased soft tissue support due to skeletal expansion.47 The weaknesses of this protocol were the required number of surgical procedures and the total length of the treatment (mean, 32 mo; range, 24–40 mo). The small sample and the differences in length of follow-up (mean, 36 mo; range, 24–49 mo) were the main limitations of the study. More experience and further long-term follow-up studies are needed to evaluate a much larger patient population with better control over the variables.
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Copyright © 2014 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
